Commit Graph
155 Commits
Author SHA1 Message Date
Frédéric Desbiens ca62edd27d Swept the stack-heavy measurement across placements, and qualified its result (#638)
#636 reported that a stack in BTCM gave a threefold tighter spread than DRAM0
for stack-heavy work. That measurement used a single code placement, which is
the methodology #631 and #633 exist to correct: the cache benchmark got an
alignment sweep and the interrupt handler got one, and this measurement never
did. It was noticed when #637 added two threads to the same image and the figure
moved -- both spreads came out near 6500 and the minima rose 15%.

The recursive body is now generated at four placements and all four are
measured, per placement, in one image.

    placement    BTCM min / spread     DRAM0 min / spread
    offset 0      41854 / 6850          42036 / 6880
    offset 16     48670 / 1946          48792 / 1978
    offset 32     42388 / 6914          42752 / 7018
    offset 48     48914 / 1860          49198 / 6786

Reproducible across runs to within a few hundred cycles.

Spread is dominated by code placement rather than by the memory holding the
stack. It ranges from 1860 to 6914 depending on where the body falls in a cache
line, and placement also moves the minimum by 17%, from 41854 to 49214. Against
that, the memory contributes a consistent but small advantage: BTCM's minimum is
lower at all four placements, by 0.4% to 0.9%.

BTCM's spread beats DRAM0's decisively at one placement of the four, offset 48,
at 1860 against 6786. At the other three the two are within 2% of each other.
So the effect #636 reported is real where it occurs and is not a property of the
part: quoting it as one invited the reader to expect it everywhere.

#636's claim should be read as qualified by this. A stack in BTCM buys a small
consistent improvement in the best case and a large improvement in spread at
some code placements and not others. Anyone building a determinism argument on
it needs the placement sweep in the loop, not a single figure.

The pad nops that displace each placement execute on every recursion level
rather than once, so each placement carries a slightly different constant cost,
about 0.6% at the widest. That cancels in the BTCM against DRAM0 comparison,
which is made at the same placement, and does not affect spread within one.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>
2026-08-18 08:51:49 -04:00
Frédéric Desbiens 1ef49338e9 Gave each thread its own MPU window, and made a violation fault (#637)
First step towards a ThreadX module port for this core: establish that PMSAv8-R
regions can be switched per thread on this part, what that costs, and that a
violation actually faults. Those are the questions worth answering before
writing a module manager on top of them.

Two threads each own a 4 KB window at the top of DRAM2. The windows are carved
out of the broad data region in mpu.c, because isolation is only meaningful in
memory no other region already covers -- every other region in that map is a
wide RW window, so a private buffer inside one of them would be reachable by
every thread whatever else was programmed.

Each thread writes its own window, which must succeed, and then reaches for the
other thread's, which must fault. The second half is the part that matters: a
test that only shows a thread reaching its own memory would pass just as well
with no protection at all.

Measured on the S32Z280-594EVB, reproducible across three runs:

    thread 0 window 0x3187E000  own: reachable  other: faulted
    thread 1 window 0x3187F000  own: reachable  other: faulted
    region switch cost: 562 to 604 cycles

The cost is worth noting for the module port to come. A context switch on this
part is about 1400 cycles, so switching one region adds roughly 40% to it, and
most of that is the dsb and isb rather than the register writes. A module switch
programming several regions should therefore batch the barriers once at the end
rather than per region.

Scope, stated plainly. The window is applied by the thread calling
thread_mpu_activate, not by the scheduler. The port's scheduler does call
_tx_execution_thread_enter under TX_ENABLE_EXECUTION_CHANGE_NOTIFY, which would
make it automatic, but that macro is read by port assembly compiled into the
shared threadx library, so enabling it would oblige all nine example targets in
this port to supply the four execution hooks. A ThreadX module port carries its
own copies of the port assembly for exactly that reason, and that is where the
switch belongs. There is no user mode, no syscall boundary and no loader here.

The fault is survivable the same way the boot probes make it survivable:
fault_expected tells the data abort handler to record the violation and resume
after the faulting access. That works in thread context because the handler
returns where it came from rather than to a fixed recovery point.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>
2026-08-17 17:59:12 -04:00
Frédéric Desbiens f535a4ec67 Measured stack-heavy work against the memory holding the stack (#636)
#635 found BTCM worth about 7.4% on a context switch with no determinism
advantage, and said why: a switch saves sixteen registers, roughly one cache
line, so the stack's cache state has almost nothing to contribute. It named the
interesting case as work with a large stack working set, said it had not been
measured, and said it should not be assumed. This measures it, and the answer
inverts the earlier one.

deep_touch recurses 24 frames, writing a frame on the way down and reading it on
the way up, so the working set is the whole descent. The cache is cleaned and
invalidated before each sample, so every descent starts cold. Two threads, one
stack in BTCM and one in DRAM0, no partner threads and no relinquish: the timed
region is entirely within one thread.

Reproducible across runs:

                      min      mean      max     spread
    stack in BTCM   42868     43031    44890       2020
    stack in DRAM0  42982     43291    49842       6860

The mean is the same to within 0.6%. The worst case is 10% lower for BTCM and
the spread is 3.4 times tighter. No sample in either configuration exceeded
twice the minimum, so these maxima are the workload rather than a timer tick --
which is the mistake that produced a false jitter result in #635 and is why the
count of interrupted samples is printed.

Put beside #635 the two measurements say opposite things and both are true.
For a context switch, a small footprint touched every time, BTCM buys throughput
and no determinism. For stack-heavy work, a large footprint touched once, it
buys determinism and almost no throughput.

The reason is that this workload is compute bound at the optimisation level this
BSP builds at: 43000 cycles for 24 frames is dominated by call and loop overhead,
so line fills are a few percent of the total and barely move the mean. What they
do is vary, and that variance is what a bank with no cache in the path removes.

So the determinism argument for TCM holds here, but it is worth 10% of worst case
and a threefold narrowing of spread, not an order of magnitude. Anyone citing
this in a safety argument should cite those numbers and not a larger claim.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>
2026-08-17 17:26:08 -04:00
Frédéric Desbiens 367d91880b Measured context-switch cost against the memory holding the stack (#635)
#634 placed a thread stack in BTCM and deliberately claimed no timing benefit,
because none had been measured. This measures it.

Two pairs of equal-priority threads hand control back and forth with
tx_thread_relinquish. One pair has both stacks in BTCM, the other in DRAM0, and
the measuring thread of each pair times the round trip in PMU cycles. Both pairs
run in one image from one copy of the measuring code, which is what makes the
comparison safe: the alignment trap that invalidated earlier work here bites
when two builds with different layouts are compared, and a code shift moves both
pairs equally.

Reproducible to the cycle across runs:

                        min    mean    max
    BTCM stacks        1370    1379   1402
    DRAM0 stacks       1476    1480   1508

BTCM is about 7.4% faster, or 110 cycles on a round trip of two switches.

Three findings that bound the claim, and the last one deflates it.

The figure holds whether the cache is warm or cold. Cleaning and invalidating
the data cache before every timed switch costs both configurations about 40
cycles and leaves the gap at 7.4%: warm it is 1334 against 1440, cold 1370
against 1476. So the advantage comes from BTCM's zero wait states, not from
avoiding cache misses.

That is because a context switch touches almost no stack -- sixteen registers,
about one cache line -- so the stack's cache state has little to contribute
either way. TCM should matter much more for threads with deep call chains or
large locals, where the stack working set is big enough for cache state to
dominate. That is not measured here and should not be assumed.

There is no determinism benefit visible in this test. Excluding preempted
samples, jitter is 32 cycles for BTCM and 28 to 34 for DRAM0 -- comparable, not
better. A first version of this measurement appeared to show BTCM with 16 times
less jitter, and that was wrong: max was reporting whichever pair a timer tick
had landed on. Across three runs the outlier appeared in the BTCM pair once and
the DRAM0 pair twice. Samples past 2000 cycles are now counted separately and
excluded from min, mean and max alike, and the count is printed so the reader
can see how many there were.

Also tried and discarded: loading the partner thread with a cache walk to create
pressure. The timed round trip includes the partner, so the walk dominated every
sample and put all 256 past the outlier threshold. The per-sample flush replaced
it and sits outside the timestamps.

The demo also starts the PMU cycle counter, which bsp_boot.c does for the probe
image and this image never ran. Without it every reading would have been zero,
which reads as a free context switch rather than as a dead counter.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>
2026-08-17 17:08:29 -04:00
Frédéric Desbiens 62e966f6bf Enabled BTCM, measured it, and put a ThreadX thread stack in it (#634)
* Enabled BTCM and measured what it offers as a data store

BTCM was disabled because of a regression that turned out not to exist; the
claim was retracted in the previous commit. It is enabled now, and this
measures why that is worth doing: 16 KB at zero wait states, where ATCM has
one, and no cache in the path at all.

Enabling it needs three things, all of which existed for ATCM already: the
region register write at EL2, an MPU region, and an ECC preload before any read
(TRM 6.2.2). BTCM accepts 32-bit stores where ATCM needs 64-bit, which
tcm_preload already handles.

The cache benchmark now sweeps three memories rather than one, four loop
alignments each. At the alignments where the loop is not instruction-fetch
bound:

    memory              cold (uncached)   warm (cached)   gain
    DRAM2 half-speed            857,540         651,436   24.0%
    DRAM0 full-speed            797,824         651,297   18.3%
    BTCM  zero wait             694,689         651,369    6.2%

Three things follow.

Warm times are identical across all three memories, within 0.02%. Once the data
cache is working the backing store barely matters, because the working set fits
in it.

Cold times rank as the reference manual predicts: BTCM fastest, then DRAM0,
then DRAM2 at half the core frequency (S32Z2 RM 6.3.6).

BTCM still shows a 6.2% gain when the caches are enabled, and that cannot be
the data cache, because an enabled TCM is Non-cacheable Non-shareable Normal
memory whatever the MPU says. It is the instruction cache on the timing loop.
This probe has always measured both caches together; three memories side by
side is what makes that visible.

The number that matters for placing data in BTCM: uncached BTCM is within 6.6%
of the best cached case, where uncached DRAM0 is 22% off it. Data in BTCM runs
at close to cache-hit speed with no cache to miss, which is the determinism
argument stated as a measurement rather than an assertion.

DRAM2's sweep is unchanged with BTCM enabled, 0 and 0 and 240 and 240, which
independently confirms the retraction.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>

* Put a ThreadX thread stack in BTCM

The code side of TCM was done in #630; this is the data side. One of the demo's
three thread stacks now lives in BTCM and the other two stay in DRAM0, so a run
exercises both paths and a mistake in either shows up.

link.lds gains a BTCM region and a .btcm_bss NOLOAD section, so a stack is an
ordinary C array with a section attribute and the linker checks it fits, rather
than a hardcoded address that silently overflows the bank.

entry.S preloads the whole bank at EL2, and that is not optional. ECC is enabled
on this part, so a TCM location must be written before it can be read (TRM
6.2.2), and a stack is read before the program writes it -- the first context
restore pops what tx_thread_create built into it. The preload has to happen
before any C runs, because the demo images do not run bsp_boot.c, which is where
the ATCM preload lives. 32-bit stores suffice for BTCM where ATCM needs 64-bit.

Why BTCM for a stack: 16 KB at zero wait states where ATCM has one, and never
cached whatever the MPU says about it. Measured in the previous commit, uncached
BTCM comes within 6.6% of the best cached case while uncached DRAM0 is 22% off
it, so stack access runs at close to cache-hit speed without depending on a line
being resident. That is the property a determinism argument needs.

What this commit does not claim: no thread-level timing improvement has been
measured. The case for BTCM here rests on the memory characterisation and on
removing the cache from the path, not on a measured context-switch figure. That
measurement is worth doing and has not been done.

Verified on the S32Z280-594EVB. The demo reports its stack addresses so the
placement is visible rather than implied -- sleeper at 0x30100000 in BTCM,
spinner and judge in DRAM0 -- and passes with 100 ticks, 20 sleeper wakeups and
20 preemptions, so a real thread schedules, preempts and context-switches on a
tightly-coupled-memory stack. The boot image still passes six of six probes.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>
2026-08-17 16:33:55 -04:00
Frédéric Desbiens 35de56853c Retracted the claim that a second TCM bank costs the data cache (#633)
entry.S and readme_s32z280.txt both stated that enabling any second TCM bank
removes all measurable data-cache benefit on this part, and gave five
configurations as evidence: ATCM alone at a 24% cache gain, four combinations
involving a second bank at none. Both concluded the cause was not a particular
bank, not its address and not the ECC preload, but enabling a second bank at
all. Both cited the Cortex-R52 and S32Z2 errata as not covering it and offered
a shared RAM pool between the LLC and the TCMs as an explanation. A defect
report went to NXP on that basis.

It was an artifact of the benchmark. That benchmark was bimodal with respect to
where its timing loop fell inside a 64-byte cache line, reporting either 24% or
nothing at all for identical silicon, and every one of those five
configurations was an edit to entry.S, so every one shifted the code that
followed and moved the loop between modes. Adding two nop instructions
reproduces the "second bank" figure exactly, to the digit. The report to NXP
has been withdrawn.

Re-measured with the alignment sweep added in #631, one bank and two are
indistinguishable:

    loop offset in line      ATCM only      ATCM + CTCM
    0                        gain 0         gain 0
    16                       gain 0         gain 0
    32                       gain 240/1000  gain 240/1000
    48                       gain 240/1000  gain 240/1000

So enabling a second bank costs nothing measurable. The banks stay disabled,
but for the ordinary reason that nothing in this example uses them, and both
texts now say that instead. Enabling one is a single line, with the ECC preload
before any read (TRM 6.2.2) and an MPU region as the only prerequisites, both
already handled for ATCM.

The readme also now states the general point, which outlasts the TCM detail: a
single-figure timing result from this example cannot be compared across builds
unless the timed loop's alignment is controlled, because almost any change
shifts code.

Comments and documentation only; no generated code changes. Verified on the
board regardless, since entry.S was touched: six of six probes pass and the
sweep is unchanged.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>
2026-08-17 13:46:33 -04:00
Frédéric Desbiens 3aaaa6700d Revalidated the ATCM handler result across four placements, and it holds (#632)
The handler comparison in #630 measured one alignment, which is the mistake
that made the cache benchmark in this example report 24% or 0% for identical
silicon. The handler body is now generated at four offsets within a cache
line, all four are measured, and the figures are reported per placement.

The claim survives. Mean cycles for the handler body:

    loop offset      code RAM    ATCM
    0                     523     383
    16                    534     377
    32                    539     375
    48                    521     383

ATCM is faster at every placement, by about 28%, and the two sets of means do
not overlap. Worst case improves as well, 510 against 694.

Two things worth recording beyond the headline.

The handler measurement is only mildly alignment sensitive, 3.5% across
placements in code RAM and 2% in ATCM, quite unlike the cache loop's two
modes. So this comparison was less fragile than the cache one, and #630's
direction was right even though its method was not defensible. The absolute
numbers differ from #630 because the body now sits behind a placement wrapper
that adds a call; the comparison is internally consistent either way.

Both variants also report identical cache sweeps, 0 and 0 and 240 and 240,
which settles the regression this branch's predecessor appeared to show. That
apparent regression was the single-alignment probe moving between its two
modes, not anything about ATCM.

One copy of the logic is kept: the wrappers inline a single always_inline
implementation, so the four placements cannot drift apart.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>
2026-08-17 13:33:43 -04:00
Frédéric Desbiens 1d3f3f8e4c Measured the cache benchmark at four alignments, because one is not enough (#631)
This benchmark was bimodal and reported a single number, which made it worse
than no benchmark. The same workload on the same silicon reports either 24%
cache benefit or none at all, decided only by where the loop falls inside a
64-byte line -- and therefore by any unrelated change that shifts code
ahead of it. Two nop instructions added to entry.S were enough to flip it.

That is not a hypothetical. A run of conclusions drawn from this probe turned
out to be measuring code layout: an interrupt-handler comparison, a claim that
enabling a second TCM bank costs all cache benefit, and a follow-up claim that
what mattered was when the TCM region register was written rather than what it
contained. The last of those was reported to NXP as a defect and has had to be
withdrawn. Enabling CTCM and adding two nops produce identical results, to the
digit, because the only measurable consequence of the enable was the eight
bytes of instructions it added.

Four copies of the loop are now generated at different offsets within a cache
line, all four are measured, and the low and high gains are both reported.
Pinning a single alignment was tried first and is not a fix: it silently picks
one of the two modes -- aligned to 64 the loop sits permanently in the low one.

Measured on the S32Z280-594EVB, reproducing exactly across runs:

    loop offset in line    cold      warm      gain
    0                      890,302   890,035   0%
    16                     890,208   889,976   0%
    32                     857,439   651,390   24.0%
    48                     857,631   651,571   24.0%

The cold pass differs between the modes as well, 890k against 857k, so the
loop is slower even with both caches off. The cold pass is instruction-fetch
bound out of code RAM at half the core frequency (S32Z2 RM 6.3.6), and how the
loop straddles lines decides how much of the data cache's contribution is
visible at all. This probe therefore measures both caches together and always
did; the sweep at least makes the variation visible instead of letting one
arbitrary placement stand in for the part.

C4 now passes if any alignment shows a 10% speedup, and says so explicitly
when the low mode does not, so the sensitivity appears in the log rather than
being discovered later.

Verified: with the sweep in place, adding 0, 8, 12 or 20 bytes of nops to
entry.S leaves the reported low and high gains unchanged. Before it, the same
shifts read 24.0%, 0%, 0% and 0%.

Also adds cache_disable_all, which the sweep needs: cache_enable was one-way,
so a second cold reading in one run was impossible.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>
2026-08-17 13:14:16 -04:00
Frédéric Desbiens b2983c08d3 Ran the interrupt handler from ATCM, and measured what that buys (#630)
The TCM work so far enabled ATCM and left it empty, which buys nothing.
This places code in it and measures the result.

link.lds gains an ATCM region and an .atcm_text section whose run address
is in the bank and whose load address is in CODE. tcm_copy_atcm_text
moves it, using 64-bit stores because ECC is enabled on this part and
ATCM requires them (Cortex-R52 TRM 6.2.2); both ends of the section are
8-byte aligned so there is no narrower tail to leave without check bits.
The copy runs after T4 and T5, which write test patterns to the first and
last words of the bank and would otherwise land on top of the code.

s32z280_atcm.elf is the same image as s32z280_boot.elf with the interrupt
service body placed in ATCM. Both targets exist so the comparison can be
repeated on one board in one session without reconfiguring. The service
routine is split into a timed wrapper that stays in .text and a body that
moves, so the wrapper's own cost appears in both measurements and cancels.

Measured in PMU cycles over 64 samples, caches enabled in both:

                 code RAM    ATCM    change
    min               454     334    -26.4%
    mean              458     340    -25.8%
    max               612     466    -23.9%
    spread            158     132    -16.5%

CNTPCT is not used for this: at 8 MHz it cannot resolve a handler body,
let alone the variation in one.

The level shift is the solid part. ATCM is a quarter faster even though
the caches were on and code RAM had the instruction cache available,
which says the handler does not stay resident between interrupts 10 ms
apart -- so each one pays a cold fetch from code RAM, which runs at half
the core frequency where ATCM runs at full speed with one wait state
(S32Z2 RM 6.3.6).

The determinism claim deserves less weight than the numbers first
suggest. The spread narrows by only 16%, and ATCM's worst case still sits
slightly above code RAM's best case, so the two distributions overlap at
the tails rather than separating. Whatever jitter remains is not
dominated by instruction fetch.

Both images pass six of six boot probes.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>
2026-08-17 09:21:27 -04:00
Frédéric Desbiens ff638dae71 Configured the LINFlexD console twice, because once is not enough at -O2 (#629)
The console driver runs its configuration sequence a single time, and that
works only because this BSP is built without an optimisation flag. Compiled
at -O2 the same sequence leaves the line corrupted: every character
partially wrong, in the pattern the file already describes for a
misconfigured module.

What makes it worth guarding against is that the failure is invisible.
UARTCR reads back exactly the value written. LINIBRR and LINFBRR read back
exactly the values written. linflexd_init returns LINFLEXD_INIT_OK. The
registers are right and the line is wrong, so nothing in the returned
status tells the caller the console cannot be trusted.

Localised by bisection: with every other file at -O2 and this one at -O0
the output is clean, and with only linflexd_init at -O2 it is corrupted,
so the fault is in the configuration sequence rather than in the per-byte
transmit path.

The mechanism is not understood, and this commit does not claim to explain
it. Tested and rejected: a 100x larger bound on the wait for
initialisation mode, a settling delay before the first LINSR read, a
settling delay after leaving initialisation mode, a barrier and read-back
between the two UARTCR writes, and waiting for LINSR to report the exit
from initialisation mode. None of those makes a single pass work at -O2.
A second pass does, at both optimisation levels, which is what this does.

Instrumented with a duplicate of the sequence forced to -O2 and reported
through a console repaired afterwards, which is how the register read-backs
above were obtained.

Verified on the S32Z280-594EVB. The boot image passes six of six probes
with the console status still reporting 0x00000000, and the reproducer
builds clean and prints correctly at both -O0 and -O2.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>
2026-08-17 07:59:23 -04:00
Frédéric Desbiens 0e7db2bf79 Stopped the generated Armv8-M readmes claiming a false origin date (#623)
Every Armv8-M port readme ends with

    09-30-2020  Initial ThreadX 6.1 version for Cortex-M85 using GNU tools.

with the core name substituted in by scripts/copy_armv8_m.sh. The date is the
shared port's, so each core inherits it whatever its own history: Cortex-M85 was
announced in 2022 and its readme claims a 2020 origin, and any core added later
gets the same treatment the moment its name joins the generator's list.

The rest of the history block is accurate, since it records changes to the shared
files. Only the closing line asserts something per-core. Reword it to describe
the Armv8-M port itself, and say where a given core's real starting point is.

Regenerating updates the twelve readmes for cortex_m33, cortex_m52, cortex_m55
and cortex_m85 across the three toolchains.

Cortex-M52 makes the point: it arrived in #519 and its readme immediately claimed
a 2020 origin for a core announced in 2023.

The ARMv7-M templates say "Initial ThreadX version 6.1.7 for Cortex-M", with no
placeholder to substitute, so they make no per-core claim and are left alone.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>
2026-08-16 08:42:53 -04:00
Armchina_JidongMeiandFrédéric Desbiens 090f8edc56 Added Cortex-M52 (Armv8.1-M) port (#519)
* ports: add Cortex-M52 (Armv8.1-M) port support

Add ThreadX port for Cortex-M52, supporting three toolchains:
- GNU (GCC)
- AC6 (Arm Compiler 6)
- IAR

Cortex-M52 is an Armv8.1-M Mainline processor sharing the same
architecture profile as Cortex-M55 and Cortex-M85. The port is
functionally identical to the existing Cortex-M85 port.

* ports: update cortex_m52 port copy script,using it update content

-Add cortex_m52 in threadx/scriprts/copy_armv8m.sh
-Using updated copy_armv8m.sh to generate new cortex_m52 port content

* Regenerated the Cortex-M52 port against dev and wired it into the checks

The port was generated from ports_arch/ARMv8-M as it stood on master, which has
since moved on. Rebasing onto dev and running scripts/copy_armv8_m.sh again
brings the twelve stale files into line, which is the point of generating them:
the core picks up every ARMv8-M fix made since without anyone porting it by hand.

Among what it picks up: "MOV r0, 0" becomes "MOV r0, #0" in the schedule and
system-return paths, the non-canonical immediate form that GNU as tolerates and
LLVM's assembler rejects; and gnu/src/tx_initialize_low_level.S goes away, since
the shared source no longer has it.

Two integration points exist only on dev, so the original change could not have
included them.

cmake/cortex_m52.cmake, so the port can be selected the documented way. Every
other Cortex-M core has one. It uses the hard float ABI, as Cortex-M55 and
Cortex-M85 do.

An entry in scripts/check_clang.sh, likewise with -mfloat-abi=hard. That flag is
not decoration: -mcpu=cortex-m52 implies Helium, and building it soft-float ends
in "multilib configuration error: No library available for MVE with soft-float
ABI" on every file, which reads as a broken port rather than a missing flag.

Verified after regenerating: scripts/copy_armv8_m.sh is a no-op, so the tree
matches its source; all 14 assembly sources and 188 C sources compile for
cortex-m52 with Arm Toolchain for Embedded 22.1.0.

Note for anyone building with GNU tools: arm-none-eabi-gcc 13.2.1 rejects
-mcpu=cortex-m52 outright. Support arrives in GCC 14.

---------

Co-authored-by: Frédéric Desbiens <frederic.desbiens@eclipse-foundation.org>
Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>
2026-08-16 08:29:46 -04:00
Frédéric Desbiens 09c190a71d Added a CMake target for the Linux sample program (#622)
The CMake build produced libthreadx.a and nothing else, so trying ThreadX on
Linux meant using the Makefile beside the port instead. Build the demo the
Makefile builds, for the linux port and its SMP counterpart.

The target is behind an option that defaults off, so an ordinary build is
unchanged and still produces just the library. -DTHREADX_SAMPLE=ON adds it:

    cmake -S . -B build -DTHREADX_ARCH=linux -DTHREADX_TOOLCHAIN=gnu \
          -DTHREADX_SAMPLE=ON
    cmake --build build --target sample_threadx

The include path uses TX_COMMON_DIR rather than naming common or common_smp,
since the top level already resolves which of the two applies.

Verified by building and running both variants. Non-SMP prints

    **** ThreadX Linux Demonstration **** (c) 1996-2020 Microsoft Corporation

and SMP prints the SMP banner, both with the demo's thread counters advancing. A
default configure with no THREADX_SAMPLE has no sample_threadx target and still
produces libthreadx.a, so nothing existing moves.

Derived from the two example_build files in #404 by Yanfeng Liu, which had the
same goal. That change also rewrote the top level's SMP selection, added
common_smp/CMakeLists.txt and added ports_smp/linux/gnu/CMakeLists.txt; all three
have since arrived on dev by other routes, so only the sample targets were still
missing. The include path needed adjusting because the original depended on
THREADX_SMP being a string suffix, which it no longer is.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>
2026-08-15 17:28:33 -04:00
Frédéric Desbiens 1296cf1740 Corrected the S32Z280 data SRAM map against the Reference Manual and the part (#621)
The RTU has 1 MB of data SRAM in three contiguous banks, and this port
described it wrongly in both directions.

  DRAM0  0x31780000  256 KB  full core speed
  DRAM1  0x317C0000  256 KB  full core speed
  DRAM2  0x31800000  512 KB  half core speed

DRAM1 was not declared at all, so 256 KB of full-speed memory went unused
and the linker's DATA region stopped at 256 KB. DRAM2 was declared as
2 MB when it is 512 KB, which mattered more: the MPU mapped 1.5 MB past
the end of the bank, and that range aliases back onto its base. Anything
placed above 0x31880000 would have shared storage with the bottom of the
region silently -- no fault, two objects at one address. Nothing was
placed there yet, so this was a trap rather than a live defect.

Sources: S32Z2 Reference Manual Rev. 5, section 6.3.6 and Table 13, and
the board. Writing distinct values to all three banks and reading them
back shows 1 MB of independent storage, and the first word past DRAM2
returns the value written to its base, which is what fixes the size.

Note that NXP's own debugger memory map, s32z2e2_memory_regions.py in
S32 Design Studio, calls the last bank 2 MB. The Reference Manual and the
silicon agree it is 512 KB.

Also corrected the description of these banks throughout. They are all
RTU-local; the earlier comments treated locality as the thing that
distinguishes them, when the actual difference is clock speed. That is
why the cache benchmark uses DRAM2 -- caching a bank that already runs at
core speed shows nothing, which is a real effect the old wording
explained with the wrong cause.

Verified on the S32Z280-594EVB: builds clean, and the boot probes pass
six of six with the MPU, GIC, interrupts, caches and both protection
faults exercised.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>
2026-08-15 17:02:01 -04:00
Frédéric Desbiens 358e7a9ea5 Stopped the remaining example scripts naming archives that were deleted (#620)
#618 fixed the arm9 and arm11 shell scripts, but not their .bat counterparts,
and did not look at cortex_r4 and cortex_r5 at all. An audit of every build
script against the files actually present in its directory found the rest.

The .bat scripts for arm9, arm11, cortex_r4 and cortex_r5 still linked libc.a,
libgcc.a and, for arm11, libnosys.a from their own example_build directories,
and the cortex_r4 and cortex_r5 shell scripts did too. Those archives went in
6.1.10 under "Removal of unneeded files", so on Windows all four examples failed
exactly as the shell versions did before #618, and on Linux the two R-profile
ones still did.

Link through the compiler driver, as the other examples have since #594.

This does not make the examples link, and the change stops there deliberately.
All four now fail the same way,

    undefined reference to `_fini'

because their linker scripts define the .init and .fini sections but not the
_init and _fini symbols, which live in crti.o and crtn.o and are omitted by
-nostartfiles. Reviving four very old cores is separate work.

Correct the comment on EXAMPLES_EXPECTED_TO_FAIL again. It had cortex_r4 and
cortex_r5 failing for want of newlib multilib variants; they do not. All four
share the single cause above, and the multilib explanation was wrong for the
R-profile pair just as it was for arm9 and arm11.

Verified by running each shell script: cortex_r4 and cortex_r5 fail on _fini
rather than on missing files, matching arm9 and arm11. The .bat changes mirror
link lines proven that way in the same directories; they cannot be run here.

Three scripts are left alone and reported instead, because a blind edit could not
be verified: ports_module/cortex_m3 and cortex_m4 have Windows-only .bat scripts
that also name sources which are absent or differ in case, and
ports_smp/mips32_interaptiv_smp needs a MIPS toolchain.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>
2026-08-15 16:58:59 -04:00
Frédéric Desbiens 20d4b977f2 Removed generated build output and per-user IDE state, and fixed two stale link lines (#618)
* Removed generated build output and stopped two scripts naming deleted archives

Three kinds of file in the tree are produced by a build rather than written by
hand, and one pair of scripts still links archives that were deleted years ago.

Keil writes ThreadX_Library.plg on every build; the two committed copies are
HTML build logs from someone's machine. Code Composer generates the makefiles
under ports/c667x/ccs/example_build/tx/Release from the project files beside
them, so makefile, objects.mk, sources.mk, subdir_rules.mk, subdir_vars.mk and
ccsObjs.opt are all regenerated output.

The arm9 and arm11 sample builds link libc.a, libgcc.a and, for arm11,
libnosys.a from their own example_build directories. Those archives were removed
in 6.1.10 under "Removal of unneeded files", and libnosys.a in #594, but the link
lines were never updated, so both examples fail immediately with

    arm-none-eabi-ld: cannot find libc.a: No such file or directory

Link through the compiler driver instead, the shape every other example in the
tree uses since #594: the driver supplies libc and libgcc, and SYSCALL_LIB is
already defined in both scripts.

That does not make either example link, and the fix stops short of that on
purpose. With the archives no longer named, both now fail on

    undefined reference to `_fini'

because their linker scripts define the .init and .fini sections but not the
_init and _fini symbols, which live in crti.o and crtn.o and are omitted by
-nostartfiles. Making those two old cores build is a separate question from
removing a stale reference, so they stay in EXAMPLES_EXPECTED_TO_FAIL, with the
comment there corrected: it blamed newlib multilib packaging, which is true of
cortex_r4 and cortex_r5 but was never the reason for arm9 and arm11.

Reproduced throughout with arm-none-eabi-gcc 13.2.1.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>

* Removed the Keil per-user state files and ignored them

Every Keil project in the tree carried a second file holding per-user state:
25 .uvoptx beside the 25 .uvprojx, 9 .uvopt beside the 9 .uvproj, and 3 .uvgui
multi-project workspace files. uVision rewrites all of them whenever a project is
opened, so they record whoever last had it open rather than anything about the
port: debugger selection, breakpoints, watch windows, window geometry.

Nothing in the tree references them, and every affected directory keeps its
.uvprojx or .uvproj, which is the file that actually describes the project.

Add ignore rules so they do not come back the next time someone opens a project
and commits.

1.4 MB across 37 files.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>
2026-08-15 16:40:19 -04:00
Frédéric Desbiens b1a48824ea Enabled ATCM on S32Z280, and left the other two banks off for a measured reason (#617)
entry.S programs ATCM to 0x30000000 and enables it at both exception levels. This
happens at EL2 deliberately: writing ENABLEEL2 from EL1 is silently ignored, which
was measured on BTCM and CTCM -- the base took and ENABLEEL10 took while
ENABLEEL2 stayed clear -- and the same write from EL2 sticks. tcm_enable() keeps
ENABLEEL10 as its success criterion for the same reason, since requiring both
would report failure for a bank that is usable at the level the caller runs at.

Programming ATCM also moves it off address 0, where CFGTCMBOOTx leaves it, so a
null-pointer write now faults instead of quietly landing in tightly-coupled
memory.

The boot image verifies rather than programs, preloads ATCM because ECC is enabled
and the check bits are not initialised by the core, and proves the bank holds data
both before the MPU is enabled and after. One MPU region covers it: the TRM
requires a region before an enabled TCM can be used, and an enabled TCM always
behaves as Non-cacheable Non-shareable Normal memory whatever the region says, so
only the permissions there matter.

BTCM and CTCM are left disabled, and that is a measurement rather than caution.
Enabling any second bank removes all measurable data-cache benefit:

    ATCM only                      cache gain 24%
    ATCM + BTCM                    cache gain  0%
    ATCM + BTCM + CTCM             cache gain  0%
    ATCM + BTCM at another base    cache gain  0%
    ATCM + CTCM, BTCM disabled     cache gain  0%

Five configurations, one variable. Not a particular bank, not its address, and not
the ECC preload: enabling a second bank at all. The benchmark buffer is in
non-RTU-local SRAM at 0x31800000, outside every TCM window, and CCSIDR reports the
same 16KB four-way cache throughout. I was wrong twice while narrowing this --
first blaming the preload, then blaming BTCM specifically -- and each was settled
by a run rather than by argument.

No erratum covers it. Checked the Cortex-R52 errata notice SDEN-857344 issue 19,
all twenty-five entries, and the S32Z2 0P91J mask set errata, whose RTU and R52
entries are ERR050509, ERR051107, ERR051153, ERR051441, ERR051613, ERR051614 and
ERR052126. A RAM pool shared between the RTU's last-level cache and the TCMs would
explain it, the LLC being documented as allocating ways to specific domains, but
that is a guess and it belongs with the other questions for NXP.

Little is lost meanwhile. The reference manual describes TCM_A as the bank
"optimized for small, regularly executed code such as interrupt service routines
or OS kernels", which is what a TCM is wanted for here, and enabling the other two
is one line each in entry.S once there is an answer.

Two checks were also wrong and are fixed. T5 reported every bank accessible while
two were disabled, because a disabled TCM's address range is serviced through AXIM
and memory answering there says nothing about the TCM; it now requires the bank to
be enabled as well. And T2 called tcm_enable() from EL1 for all three banks, which
would have switched on the very banks entry.S leaves off.

Verified on S32Z280 silicon: ATCM enabled and holding data before and after the
MPU, the cache benchmark back to 24%, protection checks X2 and X4 unchanged, and
the ThreadX demo still reporting 100 ticks with 20 preemptions.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>
2026-08-14 16:14:24 -04:00
Frédéric Desbiens 27891f3b84 Read the TCM configuration off the part, and corrected what we thought we knew (#615)
The BSP has recorded since bring-up that the TCMs are inaccessible at reset
"because nothing has programmed the TCM region registers yet". Reading those
registers shows the reason was wrong.

    ATCM  0x0000011F   64KB, 1 wait state, ENABLED at EL2 and EL1/EL0
    BTCM  0x00000014   16KB, 0 wait states, disabled
    CTCM  0x00000114   16KB, 1 wait state, disabled

Every BASEADDRESS field is zero, so ATCM is live as 64KB at address 0x00000000,
not at the 0x30000000 the reference manual documents. The reads that faulted were
of an address the TCM is not at. ATCM's enables reset set because CFGTCMBOOTx is
tied high on this part, which the Cortex-R52 TRM gives as the one exception to
"at reset all bits are 0 apart from SIZE and WAITSTATES". BTCM and CTCM really
are disabled.

The sizes and wait states match the S32Z2 reference manual exactly -- TCMA 64KB
with one wait state, TCMB 16KB with none, TCMC 16KB with one -- so the TRM's field
layout, NXP's documented configuration and the silicon all agree. That agreement
is the point of reading before writing.

ECC is implemented and enabled: IMP_MEMPROTCTLR reads 0x00000011, both RAMPROTIMP
and RAMPROTEN set. TRM 6.2.2 therefore applies rather than being hypothetical: a
TCM location must be written before it is read, or the read reports an error --
which looks exactly like "the TCM is not accessible" and sends the reader back to
region registers that were already correct. The preload widths differ too, ATCM
needing 64-bit aligned STRD or STM where BTCM and CTCM accept 32-bit stores, so a
C loop over unsigned int would leave ATCM's check bits invalid.

tcm.c reads and decodes only; nothing is programmed here. The layouts in tcm.h are
quoted from TRM r1p3 section 3.3.94 table 3-136 and section 3.3.76 table 3-114,
not inferred from a neighbouring register: BASEADDRESS is [31:13] where
IMP_PERIPHPREGIONR uses [31:12], and assuming the analogy would have been wrong by
one bit in the same way the PRBAR shift was.

The boot image reports all of it and flags any size that disagrees with the
reference manual, so a part configured differently says so rather than being
silently assumed to match this one.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>
2026-08-14 14:18:50 -04:00
Frédéric Desbiens ea91beae42 Verified nested FIQ handling on S32Z280 silicon (#614)
#613 exercised the FIQ nesting routines on the FVP. What the model could not show
is whether a real GIC-600 routes Group 0 to FIQ the same way, which is the reason
to run it here. It does, and the counts match the model exactly.

The Group 0 support ports across unchanged: IGRPEN0 and BPR0 on the CPU interface,
Group 0 in the distributor, gicv3_enable_sgi_group0, gicv3_send_sgi_group0 through
ICC_SGI0R, and the separate Group 0 acknowledge and end-of-interrupt pair. entry.S
routes the EL1 FIQ vector into _tx_thread_fiq_context_save with the acknowledge
before nesting starts, and leaves FIQ unmasked on the drop to EL1 when FIQ support
is compiled in, for the same reason as on the FVP: tx_thread_stack_build only
clears a thread's F bit in that configuration.

One structural difference from the FVP cost a link. This example reports faults
through FAULT_TAIL rather than FAULT_REPORT, so the vector table needed a new
el1_fiq_entry label that falls back to fault_el1_fiq. Placing that label inside the
TX_R52_USE_THREADX_IRQ guard broke s32z280_boot.elf, which does not define it: the
vector reference is unconditional, so the label has to be too. It now sits outside
the guard and carries its own, the same shape the demo_m2 link break in #613
forced on the FVP side.

Verified on S32Z280 silicon:

    F1 FIQ delivered and dispatched            PASS
    low-priority FIQ count  = 0x00000015       21
    high-priority FIQ count = 0x00000014       20
    nested FIQ count        = 0x00000014       20 of 20 nested
    max FIQ depth           = 0x00000002
    FIQ depth now           = 0x00000000
    F2 FIQ nested inside an FIQ handler        PASS
    F3 FIQ nesting unwound to depth zero       PASS
    F4 IRQ tick undisturbed by FIQ work        PASS
    F5 lower-priority thread still scheduled   PASS
    F6 no unexpected Group 0 INTID             PASS

No regression, both configurations checked on the board. In the FIQ build the
ThreadX demo still reports 100 ticks with 20 preemptions and the boot image still
passes its cache and protection checks. In the default build the demo is unchanged
and the image links no FIQ or Group 0 symbol at all, so the work is absent rather
than dormant where it is not wanted -- worth confirming on hardware rather than
reasoning about, because the default build now reaches the FIQ vector through a new
label even though that label only branches to the fault reporter.

entry.S assembles in all four combinations of TX_R52_USE_THREADX_IRQ and FIQ
support, on both toolchains, and every file builds with GNU without warnings and
with Arm Toolchain for Embedded 22.1.0.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>
2026-08-14 13:34:34 -04:00
Frédéric Desbiens 19d90a49c4 Exercised the nested FIQ path, the last pair nothing had ever called (#613)
_tx_thread_fiq_nesting_start and _tx_thread_fiq_nesting_end complete the set:
after #611 and #612 covered IRQ nesting on the model and on silicon, these two
were the remaining routines compiled into every build and entered by nothing.
demo_fiq.elf enters them.

FIQ needs more of the GIC than IRQ does. With a single security state the
controller delivers Group 0 as FIQ and Group 1 as IRQ, so an interrupt only
arrives as an FIQ if it has been moved into Group 0, the distributor and the CPU
interface both have Group 0 enabled, and it is acknowledged through the Group 0
registers. Group 1's acknowledge returns the spurious INTID for a Group 0
interrupt and leaves it pending, which would present as a storm rather than as an
error. gicv3.c gains IGRPEN0, BPR0, gicv3_enable_sgi_group0,
gicv3_send_sgi_group0 and the Group 0 acknowledge and EOI pair. ICC_SGI0R differs
from ICC_SGI1R only in opc1, 2 against 0, and each raises into its own group.

entry.S routes the EL1 FIQ vector into _tx_thread_fiq_context_save with the same
ordering the IRQ path needed: acknowledge in FIQ mode before nesting starts, then
nesting_start, service, nesting_end, and end-of-interrupt last. It also leaves
FIQ unmasked on the drop to EL1 when FIQ support is compiled in, because
tx_thread_stack_build only clears a thread's F bit in that configuration and
nothing else ever clears it, so an FIQ raised before the first thread ran would
otherwise be silently ignored.

Nesting an FIQ means taking an FIQ while an FIQ handler runs, which one source
cannot show, so two Group 0 SGIs are used with the second at a numerically lower
priority. The low one's handler raises the high one.

One mistake worth recording, because the guard it needed is not obvious.
TX_ENABLE_FIQ_SUPPORT is PUBLIC on the threadx target, so it reaches every image
as soon as the library is built with FIQ -- including images that link no
interrupt controller at all. demo_m2 is one of those: no gicv3.c, no
irq_dispatch.c. Referencing gicv3_acknowledge_group0 and board_fiq_service from
the FIQ vector broke its link outright. The vector is now gated on
TX_R52_USE_THREADX_IRQ as well, which is how the IRQ vector has always been
gated, and images without the infrastructure keep the fault reporter.

Verified on FVP_BaseR_AEMv8R. F1 covers the whole Group 0 chain on its own --
IGRPEN0, the ICC_SGI0R encoding, IAR0 and EOIR0, the EL1 vector and F being
unmasked -- so a failure there points somewhere other than the nesting routines.
The demo reports 21 low-priority FIQs, 20 high-priority, 20 of them nested, max
depth 2, depth unwound to zero, the IRQ tick undisturbed, threads still
scheduled and no unexpected Group 0 INTID.

All six images pass in the FIQ configuration, and the default build links no FIQ
or Group 0 symbol at all, so the work is absent rather than dormant where it is
not wanted. Both toolchains build every file, GNU with no warnings and Arm
Toolchain for Embedded 22.1.0 as well.

Not done here: the S32Z280 example is untouched, so FIQ on silicon is a separate
change, as IRQ nesting was.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>
2026-08-14 11:42:59 -04:00
Frédéric Desbiens 5a7f4f8f7c Verified nested IRQ handling on S32Z280 silicon (#612)
#611 exercised the nesting routines on the FVP and established what breaks them:
the interrupt must be acknowledged before nesting starts, or the still-pending
level-asserted timer is retaken the moment IRQ is enabled and recurses until the
stacks are gone. entry.S here carries the same ordering for the same reason, and
irq_dispatch.c splits the same way, board_irq_service taking an
already-acknowledged INTID while board_irq_handler keeps its old shape as the
non-nesting entry point.

What the model could not answer is whether a real GIC-600 agrees, and two things
could have differed.

The first is the number of implemented priority bits. Equal priorities do not
preempt and it is the low bits that vanish, so if the timer and the SGI collapse
to one value after truncation then nesting cannot happen at all -- and the test
would fail without saying why. gicv3_priority_bits discovers the count by writing
0xFF to a priority byte and reading back which bits stick, board_init records the
two effective values, and check P1 requires the SGI to still outrank the timer.
This silicon keeps five bits, the same as the FVP, so 0xA0 and 0x50 stay distinct;
that is now measured and reported rather than assumed.

The second is whether an SGI raised on real hardware is delivered at all. ICC_SGI1R
is a 64-bit AArch32 CP15 register whose encoding does not transcribe from the
AArch64 alias, so check N1 raises one from thread context and requires delivery
before nesting is involved. It arrives.

Verified on S32Z280 silicon:

    priority bits   = 0x00000005
    timer effective = 0x000000A0    sgi effective = 0x00000050
    P1 SGI outranks timer after truncation     PASS
    N1 SGI delivered and dispatched            PASS
    max depth = 0x00000002   nested SGIs = 0x00000032   depth now = 0x00000000
    N2 SGI nested inside another handler       PASS
    N3 nesting unwound to depth zero           PASS
    N4 tick still advancing after nesting      PASS
    N5 lower-priority thread still scheduled   PASS
    N6 no spurious or unexpected interrupts    PASS

Fifty nested SGIs across fifty ticks, one per tick, and depth never exceeded two.

No regression, checked in both configurations on the board. In the nesting build
the ThreadX demo still reports 100 ticks with 20 preemptions and the boot image
still passes its cache and protection checks. In the default build the image links
no nesting symbols at all and the demo is unchanged. Both toolchains compile every
file, GNU with no warnings and Arm Toolchain for Embedded 22.1.0 as well.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>
2026-08-14 11:07:06 -04:00
Frédéric Desbiens 559460bed9 Exercised the nested IRQ path, which had never once been entered (#611)
_tx_thread_irq_nesting_start and _tx_thread_irq_nesting_end have shipped in this
port since it was written, compiled into every build, and nothing had ever called
either one. Not on the model, not on silicon, not in any demo. demo_nesting.elf
enters them.

Provoking nesting needs two sources with different priorities. The generic timer
PPI was already there; the second is an SGI, which a core can raise on itself.
gicv3.c gains gicv3_enable_sgi and gicv3_send_sgi for that. ICC_SGI1R is 64-bit,
so in AArch32 it is an MCRR rather than an MCR, and the AArch64 name the
Cortex-A72 example uses, S3_0_C12_C11_5, does not transcribe to the AArch32 CP15
space. The encoding here is confirmed by check N1 in the demo, which raises an SGI
from thread context and requires it to be delivered and dispatched.

The order of the pairing is the whole difficulty, and getting it wrong does not
fail gracefully. The interrupt must be acknowledged BEFORE nesting starts. Reading
ICC_IAR1 is what raises the GIC running priority to this interrupt's own, which
masks it and everything of equal or lower priority; only then is re-enabling IRQ
safe. My first attempt called nesting_start first and acknowledged inside the
handler, so the still-pending, still-level-asserted timer was taken again the
instant IRQ was enabled, and again, until the IRQ and System stacks were
destroyed. It presented as garbage on the console and a hang with no fault to
point at, and it broke demo_m3 and demo_threadx while leaving boot_check, demo_m2
and demo_mpu passing, because only the first two depend on the tick advancing. The
Cortex-R5 example BSP states the requirement in one line: "ensure all IRQ
interrupts are cleared prior to enabling nested IRQ interrupts."

So entry.S now acknowledges in IRQ mode, carries the INTID in r4 -- which survives
the mode switch, since only SP and LR are banked -- and also pushes it on the IRQ
stack so a nested level reusing r4 cannot lose the outer level's value.
End-of-interrupt waits until after nesting_end, in IRQ mode with interrupts
masked, so dropping the running priority cannot re-admit the same interrupt.

board_irq_handler splits in two. board_irq_service does the middle part on an
already-acknowledged INTID and neither acknowledges nor EOIs; board_irq_handler
keeps its old shape as the non-nesting entry point, so images built without
TX_ENABLE_IRQ_NESTING behave exactly as before.

The nesting instrumentation in irq_dispatch.c is inert unless an image asks for
it. board_nest_provoke gates the SGI that the timer handler raises, so every other
image sees the handler it always had.

Verified on FVP_BaseR_AEMv8R. The nesting demo reports max depth 2, fifty nested
SGIs across fifty ticks, depth unwound to zero, the tick still advancing, the
low-priority thread still scheduled, and no spurious or unexpected INTIDs. In the
same nesting configuration the five existing images all pass, so the split did not
disturb the ordinary path. Both toolchains build it, GNU with no warnings and Arm
Toolchain for Embedded 22.1.0 as well.

Not done here: the S32Z280 example keeps its own irq_dispatch.c and entry.S and is
untouched, so nesting on silicon is a separate change.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>
2026-08-13 17:13:34 -04:00
Frédéric Desbiens b877305d13 Verified lazy VFP context switching on S32Z280 silicon (#609)
The FVP proved the lazy save and restore path at AR1/M5, but the board had never
run it. Doing so needed one thing the model did not: the FPU has to be turned on.

entry.S opens CPACR for CP10/CP11 and sets FPEXC.EN at EL1, guarded by __ARM_FP.
EL2 already cleared HCPTR.TCP10/TCP11, but both of the EL1 gates read 0 out of
reset, so a floating-point instruction raised an Undefined Instruction exception
before this. tx_thread_vfp_enable() does not help: it sets the per-thread software
flag that makes the context switch save and restore the registers, and never
touches the hardware. Enabling it is the BSP's job. The __ARM_FP guard is what
keeps a soft-float build assemblable, since "vmsr fpexc" is not a valid
instruction for that target at all.

demo_vfp_s32z280.c is the FVP's demo_m5.c test design over the LINFlexD console.
The design is kept deliberately, because the two halves of the VFP context path
need separate provocation: "fp check" holds eight live doubles across
tx_thread_sleep, eight being enough to force the callee-saved D8-D15 bank that a
solicited switch must preserve, while "fp busy" sits at the lowest priority and
never sleeps, so the tick interrupts it mid-computation and exercises the
interrupt half, D0-D15 plus FPSCR. Only these two threads opt in, so the test
also shows that opting in is what does the work.

s32z280_vfp.elf is gated on TX_R52_ENABLE_VFP, as demo_m5.elf is in the FVP
example, since the image is meaningless unless the library was built with a
floating-point ABI.

Also made this example's -Wl,--no-warn-rwx-segments conditional on the compiler
being GNU. #604 did that for the FVP example and this file still carried the
literal, so ld.lld failed the link with "unknown argument". With that fixed the
S32Z280 images build with Arm Toolchain for Embedded too.

Verified on S32Z280 silicon:

    V2 D8-D15 bank preserved across switches   PASS   50 solicited switches
    iterations = 0x000140A8                           82,088 interrupted rounds
    corruptions = 0x00000000
    V3 interrupted FP thread made progress     PASS
    V4 no FP corruption across interrupts      PASS
    filex_ptr = 0xF11EF11E
    V5 VFP flag did not alias filex_ptr        PASS
    PASS lazy VFP context switch verified on silicon

No regression: the soft-float build is warning-free and its image contains no vmsr
at all, confirming the guard elides the block, and the existing demo still reports
100 ticks with 20 preemptions on the board. Both S32Z280 images also build with
Arm Toolchain for Embedded 22.1.0, the hard-float VFP image included. No FVP file
is touched.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>
2026-08-13 17:07:36 -04:00
Frédéric Desbiens acdc02b2fc Assembled the code behind feature macros, and fixed the POP it found (#608)
scripts/check_clang.sh assembled every source with default flags, so the
preprocessor discarded each #ifdef block before the assembler saw it. Nothing in
the tree had ever assembled a guarded path. That covers the VFP context save and
restore in ten ports, and 218 files carrying TX_LOW_POWER or
TX_ENABLE_EXECUTION_CHANGE_NOTIFY.

Turning those on found a defect. The Cortex-M0 and Cortex-M23 execution-profile
paths bracket their call with

    PUSH    {r0, lr}
    BL      _tx_execution_isr_enter
    POP     {r0, lr}

and the last of those is invalid on Armv6-M and Armv8-M Baseline, where the
16-bit Thumb POP takes r0-r7 and pc and nothing else. GNU rejects it as well --
"cannot honor width suffix" -- so TX_ENABLE_EXECUTION_CHANGE_NOTIFY and
TX_EXECUTION_PROFILE_ENABLE have never been buildable on either port with either
toolchain. Four files, all the same shape.

The fix pops into a scratch register and moves it, MOV to a high register being
permitted where POP is not. r1 is free: the BL may clobber r0-r3, which is the
reason r0 is saved in the first place. Disassembling the result gives
push {r0, lr} / bl / pop {r0, r1} / mov lr, r1 / bx lr, one 16-bit instruction
more than before and otherwise the same.

Two findings that were not defects, recorded in the script so they are not
rediscovered:

Cortex-R4 needs an -mfpu to assemble its VFP path, because its FPU is an option
rather than part of the core. GNU fails identically without one, so this is a
flags requirement and not a toolchain divergence.

The A profile ports must not be given one. Adding -mfpu=vfpv3-d16 uniformly broke
28 files with "register expected", because those ports save D16-D31 and a -d16
FPU does not have those registers. Their defaults were already right.

The new stage runs under --asm-only as well, needing no target C library, and
reports 37 of 37 VFP files, 8 of 8 TX_LOW_POWER and 218 of 218
TX_ENABLE_EXECUTION_CHANGE_NOTIFY. Restoring the POP for one run makes it fail
with 217 of 218 and name the file and the error, so the stage is not vacuous.
The other four stages are unchanged: 711 of 711 assembled, 185 of 185 common C
sources for each of nine cores, 42 of 42 script-driven examples and 5 of 5 CMake
images.

The fixed code is verified to assemble with both toolchains and to encode as
intended. It is not verified running: there is no Cortex-M0 or Cortex-M23 model
here, and these are context save and restore paths, so that gap is worth stating.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>
2026-08-13 10:14:53 -04:00
Frédéric Desbiens 010a6c9fbb Gave the gnu ports a CMake build, which most of them lacked (#607)
The project guidelines ask for CMake and Ninja, but only 15 of the 59 gnu port
directories had a CMakeLists.txt. None of the 27 AArch64 ports had one, so the
architecture whose examples were repaired over the last few changes still could
not be built the way the project says to build it, and nothing in CI could
compile it.

Add a CMakeLists.txt to the 44 that lacked one. Three of them are templates in
ports_arch, because 34 of the 44 are generated: the ARMv7-A and AArch64 source
lists are uniform within each family, so one template per family serves every
core in it and update.sh distributes it. The other 10 ports have no generator
and get their own file.

Add the toolchain files those ports select, following the shape of
cmake/cortex_a9.cmake. AArch64 needs a base file of its own rather than a
variant of arm-none-eabi.cmake: it has no -marm or -mthumb to choose between and
no -mfloat-abi, and aarch64-none-elf-gcc rejects -mlong-calls outright, so that
flag cannot be carried across. The tools are named without a path, unlike
cmake/cortex_r52.cmake which pins one, because pinning 30 files to a single
machine's directory layout is the problem the previous change removed from the
launch configurations.

Three toolchain files cover ports that already had a CMakeLists.txt but no way
to select it: the Armv8-M mainline gnu ports, cortex_m33, cortex_m55 and
cortex_m85. Without cmake/<arch>.cmake the documented invocation cannot reach
them.

The top level needed one fix. It derives the SMP port directory as
<arch>_smp, but ports_smp/linux and ports_smp/win64 predate that convention and
carry no suffix, so those two could never be configured. Fall back to the bare
name when the suffixed directory is absent. The check only fires when the
suffixed directory does not exist, so no port that already resolved changes
behaviour, and ports_smp/win64's existing CMakeLists.txt becomes reachable too.

Verified by configuring and building every one: 53 of 53 static libraries build
with cmake -G Ninja, using Arm GNU Toolchain 14.3.Rel1 for both arm-none-eabi
and aarch64-none-elf. That covers the 44 new ports plus the 9 that already
worked, and includes ports_smp/linux, which failed before the fallback.
scripts/check_ports.sh passes, so the three templates and their 34 generated
copies agree.

Six gnu ports are still outside the CMake build, all for want of a compiler
rather than a CMakeLists.txt: rxv1, rxv2 and rxv3 need the Renesas RX GNU
toolchain and mips32_interaptiv_smp needs a MIPS one, neither of which is
available here, so writing toolchain files for them would mean shipping
untested guesses. risc-v32 and risc-v64 already build through their own
differently named toolchain files.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>
2026-08-12 12:43:57 -04:00
Frédéric Desbiens 990d51b65d Brought up ThreadX on S32Z280 silicon and fixed the MPU encoding it exposed (#606)
* Added an S32Z280-594EVB example build for the Cortex-R52 port

First silicon bring-up for the Cortex-R52 port: an image that boots RTU0 core 0
on the NXP S32Z280-594EVB, drops from EL2 to EL1 and reports what the core says
about itself.  Gated behind TX_R52_BUILD_S32Z280_EXAMPLE, separate from the FVP
example option so that FVP regression is unaffected by bring-up work and the
two boards' differing reset states cannot interact.

Verified on the board.  The image runs from reset and reaches its completion
breakpoint, and the two CPSR values are the point of the exercise: mode 0x1A
(Hyp) at EL2 then 0x13 (Supervisor) at EL1, i.e. the EL2 to EL1 drop performed
by this code on silicon rather than on a model.

    MIDR      0x411FD133   Cortex-R52 r1p3, part 0xD13
    MPUIR     0x00001400   20 MPU regions at EL1
    HMPUIR    0x00000014   EL2
    CTR       0x8144C004
    MPIDR     0x80000000
    ID_PFR0   0x00000131
    ID_PFR1   0x10111001   virtualisation field 1: EL2 implemented
    SCTLR     0x70C50838   MPU, D-cache and I-cache all off at reset
    CNTFRQ    0x00000000

The FVP reports MIDR 0x410FD0F0, part 0xD0F, which is an architecture envelope
model and not a Cortex-R52 -- so these are the first implementation-specific
numbers the port has had.

Three silicon facts the code exists to encode, each of which presents as
working hardware that quietly does the wrong thing:

  - The core resets in THUMB state.  CPSR reads 0x1FA out of reset because the
    boot instruction NXP plants at the boot address is a T32 branch, so _start
    is T32 and switches to A32 itself.  An A32 entry would execute the first
    halfword of its own instruction as Thumb.

  - The debugger holds every core in debug state.  NXP's
    _reset_to_first_instruction() asserts MDM_AP CONTROL2[19:16] =
    CR52_RTU0_{3,2,1,0}_EDBGREQ and never clears them, though its own comment
    says start_debug_by_core_name() does.  While asserted the core executes
    nothing, yet registers and memory still respond and MC_ME/RGM report the
    core released and clocked.  tools/read_identity.gdb clears core 0's bit and
    verifies the clear took.

  - CNTFRQ reads zero, exactly as on the FVP, and is writable only at the
    highest implemented exception level.  entry.S records it rather than
    writing a value, because the correct frequency for this board is not yet
    established and a wrong one would silently mis-scale every derived
    interval.  Timer work must program it first.

Memory map: .text is linked and loaded at 0x79900000, the instruction-fetch
window and the reset address (MC_ME_PRTN0_CORE0_ADDR reads exactly that).  It
is writable over the debug AXI port despite NXP's map declaring it read-only,
so no load-address alias is needed for a debugger-loaded image; a flash-booted
one would use the data alias at 0x32100000, which is the same physical SRAM as
confirmed by a sentinel write.  Data, bss and the per-mode stacks go to
RTU-local data SRAM at 0x31780000.  The TCMs are absent on purpose: they are
inaccessible at reset until their region registers are programmed, so nothing
needed for early boot can live there.

Reporting is built so that a failure cannot read as a success: boot_stage
distinguishes a fault from a hang and fault handlers record vector, syndrome
and address before parking; r52_identity.magic is written last so a
half-filled structure is detectable; and bsp_done() is a deliberate breakpoint
target so completion is observed rather than inferred from a timeout.

The image does not link ThreadX, so a failure here is unambiguously a boot or
board problem rather than a kernel one -- the same reasoning as the FVP's
boot_check.elf.

Not included: console, timer, GIC, MPU programming.  LIN9 reaches the host
through the daughtercard USB-UART, which is LINFlex_9 at 0x42980000 and not
LINFlex_0; what is missing is the clock configuration needed to compute a baud
rate, and a console at the wrong rate produces garbage indistinguishable from a
crash.  Hence reporting through memory for now.

FVP example builds and passes 6/6 unchanged.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>

* Added a LINFlexD console to the S32Z280-594EVB example

Polled transmit console on LINFlex_9, which is the instance wired to the
daughtercard USB-UART through jumper J248.  Not LINFlex_0: that is merely the
first instance in the Reference Manual's list and reaches no connector on this
board.  bsp_boot.c now prints the identity registers as well as recording them
in memory; the memory copy stays, because it is what proved the boot path
before a console existed and it still works if the console is misconfigured.

The baud rate was derived rather than assumed, which mattered because a console
at the wrong rate produces garbage indistinguishable from a crash:

  - LINFlex_9 is clocked by P5_LIN_BAUD_CLK, driven by MC_CGM_5 MUX 2.
  - Read from the board: MUX_2_CSS selects source 2, MUX_2_DC_0 divides by 1.
  - The EVB carries a 40 MHz crystal (UG10268 section 3.3.1.1), so 40 MHz.
  - LFDIV = 40000000 / (16 * 115200) = 21.7014, giving LINIBRR 21 and
    LINFBRR 11, for an actual 115274 baud -- 0.06% error.

Those are exactly the values the BootROM had already left in the registers,
which is the corroboration for the 40 MHz figure rather than merely a
plausible-looking calculation.

They are programmed here anyway instead of inherited, for two reasons.
Inheriting register state makes this image's behaviour depend on how the board
was last booted.  And the BootROM's own configuration is wrong for a console:
it leaves PCE set and TxEn clear, because it is listening for a serial-boot
download rather than printing, so a host terminal on 8N1 would see framing
errors.

Verified on the board: the image reaches its completion breakpoint with the
console calls in the path, so every byte was accepted and UARTSR.DTF was set
for each -- the transmitter is configured, enabled and clocked.  That does not
by itself prove the rate, since DTF sets at any baud; the rate rests on the
arithmetic above and the BootROM's independently matching divisors.  Observing
the text needs the daughtercard USB-UART connected to a host terminal at
115200 8N1.

Register offsets and bit positions are from Reference Manual section 75.5.1
and the UARTCR/UARTSR diagrams.  PCE at bit 2 and TxEn at bit 4 are called out
in the source because they are easy to transpose and the failure is silent.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>

* Fixed two silent failures in the S32Z280 LINFlexD console

The console transmitted from the first attempt, but what arrived on the wire
was wrong in two independent ways, neither of which the target could detect.
Both are now fixed and the output is byte-for-byte correct, captured from the
USB-UART rather than read off a terminal.

1.  UARTCR was written outside initialisation mode.

    Setting LINCR1.INIT does not put the module in initialisation mode in the
    same cycle, and most of UARTCR is writable only there.  Configuring
    immediately after the LINCR1 write half-worked: bits being *set* took
    effect while bits being *cleared* did not.  TxEn came on, but PCE stayed
    on, so the line ran 8E1 against a host expecting 8N1.  That corrupts only
    those characters whose parity bit happens to be 0 and leaves the rest
    readable, which looks like a marginal baud rate rather than a framing
    error -- and would have sent the next hour into the clock tree.

    linflexd_init() now polls LINSR[LINS] until the module reports
    initialisation mode, reads UARTCR back afterwards, and returns a status
    mask.  bsp_boot.c records it and prints it as CONSOLE; 0 means both the
    mode entry and every field write were confirmed rather than assumed.

2.  DTF was cleared after the byte rather than waited on.

    DTF is write-one-to-clear and does not de-assert in the same cycle as the
    clearing write, so the next byte's poll could observe the previous byte's
    flag, conclude the line was free while it was still busy, and have its own
    write silently discarded.  That cost exactly one character after every
    "\r\n" pair -- the only place two bytes go out back to back -- so the
    first letter of every line went missing: MIDR read as IDR, SCTLR as CTLR.

    The transmit sequence is now write, wait for DTF, clear DTF, then wait for
    the clear to take effect, with the same bounded guard as the init loop so
    a stuck flag degrades to slow output rather than a hung boot.

    Clearing before the write was tried and is worse, not better: the write
    then lands while the previous byte is still shifting and is dropped, and
    the poll afterwards sees the previous byte's completion, so most of the
    output disappears.  That failure is what established that the transmitter
    discards writes while busy, which is the fact both bugs turn on.  The
    source says so, because the ordering looks arbitrary otherwise.

Verified end to end on the board, with the USB-UART passed through to WSL2 so
the received bytes could be compared against what the code intended to send:

    === ThreadX Cortex-R52 :: NXP S32Z280-594EVB ===
    MIDR      = 0x411FD133
    MPUIR     = 0x00001400
    HMPUIR    = 0x00000014
    CTR       = 0x8144C004
    MPIDR     = 0x80000000
    ID_PFR0   = 0x00000131
    ID_PFR1   = 0x10111001
    SCTLR     = 0x70C50838
    CNTFRQ    = 0x00000000
    CPSR@EL2  = 0x000001DA
    CPSR@EL1  = 0x600001D3
    EL1 MPU regions: 00000014
    CONSOLE   = 0x00000000
    === boot complete ===

Reaching the completion breakpoint proved only that the transmitter ran; it
could not have caught either fault.  Comparing bytes is what did.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>

* Added generic timer support to the S32Z280-594EVB example

The Arm generic timer now runs on silicon: CNTFRQ is programmed at EL2 and a
one-shot compare fires when it should.

    CNTFRQ programmed = 0x007A1200 (8000000)
    elapsed counts    = 8000043   (requested 8000000, +0.001%)
    host interval     = 1.0033 s

Both halves matter.  The elapsed count shows the counter and the compare agree
with each other; the host interval shows the rate is actually 8 MHz rather than
merely self-consistent, which a wrong CNTFRQ would also produce.  The residual
43 counts is about 5 us of polling overhead.

CNTFRQ reads zero out of reset here, exactly as on the Armv8-R AEM FVP -- so
that FVP behaviour is real silicon behaviour, not a model artefact, and the
port readme's warning to re-verify it was well placed.  The parallel stops
there: the FVP also leaves the system counter itself stopped and its BSP must
start it, whereas on this board the BootROM has the counter running and only
the software-declared constant was missing.  CNTFRQ is writable only at the
highest implemented exception level, so entry.S programs it before the drop to
EL1.

8 MHz was established three independent ways rather than assumed:

  - Measured: CNTPCT sampled against host wall-clock time over a 32-second
    interval gave 8.0227 MHz.
  - Derived: RTU.GPR CFG_CNTDV reads 4, so the divider is (4+1) = 5, and the
    board's FXOSC is 40 MHz -- itself already corroborated by the LINFlexD
    baud divisors the BootROM left behind.  40 / 5 = 8.
  - Confirmed: the one-shot compare above.

The compare is polled with the interrupt masked, deliberately.  There is no
GIC configured yet, and proving the timer counts and fires first means a later
interrupt failure cannot be confused with the timer itself being wrong -- the
same staging that made the console tractable.

Also recorded, from a detour that cost a run: RTU0.GPR CFG_CNTDV at 0x76120010
is readable by the debugger, which returns 4, but a load from the core at EL1
kills the image.  No fault handler runs, boot_stage stays at 4, and the debug
connection drops -- the signature of a stalled bus access rather than an abort,
and a failure mode that leaves nothing on-target to inspect.  The debugger
reaches that window over the AXI-AP, which does not go through whatever gates
the core's own access to RTU peripheral space.  The image no longer touches it;
the value lives in platform.h instead.  This is the second address on this part
that is debugger-visible but not core-reachable, so peripheral windows are now
worth probing from the core before relying on them.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>

* Enabled the R52 peripheral port and located the GIC on S32Z280

Two peripheral windows on this part stalled the core outright when read: no
abort, no fault handler, boot_stage frozen at its last value, and the debug
connection dropping with it.  A stall gives you nothing on-target to inspect,
so both were found by printing a marker before each access and seeing which
marker came last.  The Cortex-R52 TRM r1p3 (100026_0103_00_en) explains both;
NXP's reference manual mentions neither.

1.  The low-latency peripheral port is disabled at reset.

    IMP_PERIPHPREGIONR (TRM 3.3.80) describes a region at 0x76000000 of 4 MB
    on this part -- the RTU peripheral space -- with separate enables for EL2
    and EL1/0.  Read from the board it was 0x76000034: base 0x76000000, size
    0b01101 = 4 MB, and both enable bits clear.  The TRM is explicit that each
    "resets to 0".  Until they are set, every access in that window stalls.

    entry.S now sets both at EL2, which is also where it has to happen: EL1
    writes to this register trap to EL2 when HACTLR.PERIPHPREGIONR is clear.
    PERIPHPRG now reads 0x76000037 and the core reads RTU0.GPR CFG_CNTDV = 4
    for itself -- the same value the debugger saw, which independently
    confirms the divider behind the 8 MHz counter rate from the core's own
    view rather than the debug path's.

2.  The GIC is where NXP says, and needs an MPU mapping to reach.

    IMP_CBAR (TRM 3.3.17) holds the physical base of the memory-mapped GIC
    distributor in bits [31:21], its reset value wired from CFGPERIPHBASE.
    Read from the board it is 0x47800000, confirming NXP's memory map from the
    hardware rather than from a vendor debugger script -- the reference manual
    contains no GIC base address anywhere.  NXP's cryptic note that the "R52
    Cluster set addr [31:21]" is just CFGPERIPHBASE[31:21] restated.

    TRM Table 9-1 gives the frame layout relative to that base: distributor at
    +0x000000, redistributor control at +0x100000, redistributor SGI/PPI at
    +0x110000, then +0x20000 per further core.  That matches what the FVP
    example's driver already assumes, so it should port with address changes.

    The distributor still stalls, and the TRM says why: "Ensure that the memory
    region used for the GIC Distributor is configured as Device nGnRnE."  The
    MPU is disabled here -- SCTLR.M reads 0 -- so nothing maps that region.
    Enabling the peripheral port does not help, the GIC being outside that
    window and reached over AXIM.  Reading it waits on MPU programming, which
    is the next piece of work; the probe is removed rather than left in, since
    while present it stalled every run and cost the console and timer results
    that precede it.

gic_probe.c holds the two system-register reads.  They cannot hang the bus,
unlike the memory accesses they diagnose, which is the point of them.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>

* Reached the GIC on S32Z280 by mapping it Device nGnRnE

The GIC distributor and redistributor now respond on silicon:

    MPU rgns   = 0x00000003
    SCTLR      = 0x70C50839      (M set; caches still off)
    GICD_PIDR2 = 0x0000003B      architecture revision 3 = GICv3
    GICD_TYPER = 0x0248001E
    GICR_PIDR2 = 0x0000003B      redistributor at base + 0x100000

Three independent sources had to agree to get here, and NXP's reference manual
supplied none of them.  IMP_CBAR reports the distributor base from the hardware
(0x47800000).  Cortex-R52 TRM Table 9-1 gives the frame layout: distributor at
+0x000000, redistributor control at +0x100000, SGI/PPI at +0x110000, then
+0x20000 per further core -- the layout the FVP example's gicv3.c already
assumes.  And the TRM requires the region be Device nGnRnE, which was confirmed
rather than taken on faith: mapped Normal write-back the distributor stalls the
core outright, mapped Device it reads 0x3B.

mpu.c is ported from the FVP example, keeping its PRBAR/PRLAR encoding and the
reversed-AP-bit-order finding, with an S32Z280 region table.  Caches are left
off: the point of this pass was reaching the GIC, and the debugger writes this
image straight into SRAM behind the caches, so enabling C and I deserves its own
step and its own check.

Diagnosis needed two new pieces of machinery, both kept:

  - Memory-resident progress markers (probe_stage), mirroring the console
    markers.  Enabling the MPU can take the core down in a way that records no
    fault AND takes the console with it, so boot_stage alone could not say how
    far a risky sequence got.  With markers inside mpu_init the failure went
    from "somewhere in the MPU code" to "the SCTLR.M write itself" in one run.

  - Resolving symbol addresses from the current ELF with nm on every
    post-mortem.  Adding probe_stage to the .data block shifted fault_vector,
    so reusing addresses across builds reads the wrong words -- which nearly
    produced a conclusion from a stale read.

OPEN QUESTION, recorded in mpu.c rather than papered over.  A five-region map
that adds a second Device window for the RTU peripheral space (0x76000000, 4 MB)
makes the SCTLR.M write kill the core: all regions program without error,
probe_stage reaches 0x42, and the marker one instruction later never lands.  No
exception is taken, so it stalls rather than aborts.  Coverage is not the
explanation -- that map spanned the whole address space, and an earlier comment
of mine claiming otherwise was wrong and has been corrected.  The cause is not
known.  Consequence: RTU peripheral access after the MPU is enabled is untested;
the CFG_CNTDV read this image does happens before the enable.

Also not tightened yet: code is writable and data executable in this map.  Wrong
for a protection demo, right for bring-up where an unmapped address costs a
silent stall rather than a fault.  Narrowing it belongs with the ThreadX
integration, which can verify it.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>

* Fixed an out-of-bounds MPU table write that made enabling the MPU stall the core

The five-region map now programs correctly and the MPU enables with the GIC
reachable:

    R  idx  PRBAR      PRLAR
    R  0    00000000   477FFFC1
    R  1    47800002   479FFFC3    GIC, XN, Device nGnRnE
    R  2    47A00000   75FFFFC1
    R  3    76000002   763FFFC3    RTU peripherals, XN, Device nGnRnE
    R  4    76400000   FFFFFFC1
    MPU rgns = 5, SCTLR = 0x70C50839 (M set)
    GICD_PIDR2 = 0x3B, GICD_TYPER = 0x0248001E, GICR_PIDR2 = 0x3B

The bug was mine and it was simple: mpu_regions[] is declared with a fixed
size, and the FVP example this file came from sized it [3] to match the three
regions it programs.  A five-region table wrote mpu_regions[3] and [4] past the
end of the array.

What made it hard to see is what the corruption produced.  Every region
appeared to program without error, and the failure was a stall on the SCTLR.M
write -- no abort, no fault handler, no exception, and the debug connection
dropping.  Reading the regions back out of the hardware, with the MPU
deliberately left disabled so the readback could not itself stall, showed
region 3 with base 0x00000000 instead of 0x76000000.  With its correct limit
that region spanned 0x00000000-0x763FFFFF and overlapped regions 0 to 2, and
PMSAv8-R leaves overlapping regions UNPREDICTABLE -- so stalling was permitted
behaviour rather than a hardware fault.

One bug accounts for every observation: three regions worked, five failed, and
it failed identically whether the extra window was Device or Normal, because
the memory type was never involved.

Fixes: the table capacity is now named (MPU_TABLE_REGIONS) and sized 16, and
mpu_init checks mpu_regions_used against it as well as against MPUIR.  The
existing check only compared against the hardware's region count, which said 20
and told us nothing about the array.

Two earlier claims of mine, corrected here rather than left standing.  A comment
asserting "narrow coverage was the problem" was wrong: the failing map covered
the whole address space.  And this is NOT a defect inherited from the FVP
example -- that code declares [3] and uses three regions, entirely
self-consistent.  Worth offering upstream only as hardening: the bare [3] with
no bound check is what let a growing map overrun it silently.

The region readback is kept in the image.  It costs eight lines a boot and
verifies the map against the hardware every time, which is precisely what
turned an unexplained stall into a one-line diagnosis.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>

* Enabled interrupt-driven ticks by clearing SCTLR.TE

Timer interrupts are delivered, acknowledged and re-armed on silicon:

    SCTLR       = 0x30C50838 -> 0x30C50839   (TE cleared, M set)
    IRQ count   = 7
    timer INTID = 30                          measured, not assumed
    spurious    = 0
    unexpected  = 0

SCTLR.TE -- Thumb Exception enable -- RESETS SET on this part.  Every vector
table in entry.S is A32, so the core entered each exception in T32 state,
decoded an A32 branch as Thumb, landed mid-instruction at a misaligned address
and took an undefined-instruction exception, which repeated the same way.  No
handler ever ran.  entry.S now clears it at EL1 and clears HSCTLR.TE at EL2.

The consequence was worse than a crash: it made every fault invisible.
boot_stage stayed at its last value, fault_vector stayed zero, and the core sat
at el1_vectors+4.  A data abort from an unmapped peripheral, an abort from an
overlapping MPU region, and a correctly delivered timer interrupt all presented
identically -- an unexplained hang with nothing recorded.  What gave it away was
reading the banked registers: LR_irq and SPSR_irq showed an IRQ had been taken
from SVC with interrupts enabled, CPSR showed UND mode with T set, and LR_und
pointed at a misaligned address inside the A32 vector table.

The Armv8-R AEM FVP resets with TE clear, which is why the same vector tables
work there and why nothing in the FVP work anticipated this.

This commit also corrects earlier comments of mine.  Several places described
these failures as "a stalled bus access rather than an abort", with the absence
of a recorded fault as the evidence.  That was wrong: they were ordinary
exceptions whose handlers were unreachable.  The two underlying bugs -- the
peripheral port disabled at reset, and the out-of-bounds MPU table write -- were
real and are correctly fixed, but the explanation for why they presented so
mutely was not.  Fixed in platform.h, mpu.c and bsp_boot.c.

Interrupt plumbing: gicv3.c is ported from the FVP example with the frame bases
in platform.h, derived from IMP_CBAR and TRM Table 9-1.  el1_irq_entry in
entry.S uses the classic A32 form rather than ThreadX's context save/restore,
since this image does not link the kernel.  irq_dispatch.c counts ticks instead
of calling _tx_timer_interrupt, and keeps separate spurious and unexpected-INTID
counters so that "no interrupt arrived" and "an interrupt arrived and was
mishandled" cannot be confused.  timer_start_oneshot_irq arms with IMASK clear;
the polled timer_start_oneshot keeps IMASK set, and the two are separate
functions because either mistake is silent.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>

* Ran ThreadX on S32Z280 silicon with threads, tick and preemption

The kernel runs on the board:

    === ThreadX Cortex-R52 :: S32Z280-594EVB ===
    console   = 0x00000000
    entering kernel

    === ThreadX on S32Z280: results ===
    ticks     = 0x00000064      100 ticks
    sleeper   = 0x00000014       20 wakeups
    spinner   = 0x00159B48    1415496 iterations
    preempt   = 0x00000014       20 preemptions
    PASS threads, tick and preemption all verified

The figures are internally consistent, which is what makes them evidence rather
than encouragement: 100 ticks elapsed for a 100-tick sleep, so the tick rate is
exactly as configured; 20 sleeper wakeups is precisely 100/5 for a 5-tick sleep;
and 20 preemptions means every wakeup took the core from a runnable
lower-priority thread rather than receiving it by cooperative handoff.

This validates the context-switch assembly merged in #579 on real Cortex-R52
silicon.  Until now it had only run against the Armv8-R AEM FVP, which reports
MIDR part 0xD0F -- an architecture envelope model, not an R52 implementation.

The demo judges four things separately because on first silicon they fail
independently: that time advanced (the GIC delivers the timer PPI and
_tx_timer_interrupt is reached), that tx_thread_sleep returned (tick-driven
scheduling, not merely the interrupt), that the lowest-priority thread ran (the
sleeper actually yielded), and that the sleeper resumed while the spinner was
runnable (preemption).  A demo that only counted whether both threads ran would
pass with a broken tick if they happened to yield to each other.

Integration pieces, all from the FVP example with the board's differences:

  - tx_initialize_low_level.S publishes the system stack and the first free
    address, then calls board_init().  Shorter than the A-profile reference
    ports because entry.S has already given every mode its own stack from
    dedicated linker regions.

  - entry.S routes the IRQ vector through _tx_thread_context_save and
    _tx_thread_context_restore under TX_R52_USE_THREADX_IRQ, keeping the
    standalone A32 handler for s32z280_boot.elf, which does not link the kernel
    so that a boot failure there stays unambiguous.

  - board_init() runs mpu_init() FIRST.  The GIC distributor is unreachable
    until its region is mapped Device nGnRnE, so any GIC access before the MPU
    is enabled aborts.

  - link.lds provides _end as well as end; _tx_initialize_low_level publishes
    unused memory from _end.

  - bsp_done() is defined in the demo rather than shared from bsp_boot.c, whose
    bsp_main would collide with the demo's.

s32z280_boot.elf still builds and the FVP example still passes 6/6.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>

* Tightened the S32Z280 MPU map and verified protection is enforced

The map now carries real permissions -- code read-only and executable, data
writable and never executable, peripherals Device nGnRnE and never executable,
everything else unmapped -- and the enforcement is demonstrated rather than
asserted:

    X1 write to read-only code region
    faults     = 0x00000001
    fault DFSR = 0x00000A0C      bit 11 (WnR) set: a write fault
    fault addr = 0x79900000      the address written
    X2 PASS write to code faulted and was recovered

Exactly one fault, identified as a write, at the precise address, followed by
successful resumption.  ThreadX still passes on the same map: ticks 100,
sleeper 20, spinner ~1e6, preempt 20, and IRQ count keeps advancing during the
protection test.

Reading SCTLR back or listing the programmed regions would only show what was
configured.  Provoking the violation shows it is enforced, which is the claim
that matters for a protection story.

entry.S gains a recoverable data-abort path, gated on a fault_expected flag the
test arms.  It records DFSR and DFAR, counts the fault, and resumes at the
instruction after the faulting access -- lr on data-abort entry is the faulting
address plus 8, so subs pc, lr, #4 skips the access instead of retrying it
forever.  Unarmed, a data abort stays fatal and reported, which is what a real
bug should get.

This supersedes the permissive bring-up map, and the reason that map existed is
worth recording: a narrow map had failed earlier and the cause was unknown, so
coverage was blamed.  Coverage was never the problem.  An out-of-bounds write to
a [3]-sized region table put a region at base 0 overlapping everything, and
SCTLR.TE being set meant the resulting abort could not reach a handler.  With
both fixed a narrow map works first time, and -- more usefully -- a mistake in it
now reports vector, syndrome and faulting address instead of hanging mutely.

Until TE was cleared no fault handler on this board could run, so no protection
claim about it could be tested at all.  This is the first one that could.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>

* Enabled the S32Z280 caches, with an honest effectiveness result

Both caches are on and verified from SCTLR:

    CLIDR      = 0x09200003
    SCTLR      = 0x30C50839 -> 0x30C5183D    (C and I set)
    cachesOn   = 1
    counts off = 0x00094DF4
    counts on  = 0x00094CC8
    gain/1000  = 0
    C3 PASS caches enabled (SCTLR.C and SCTLR.I set)
    C4 no significant speedup -- expected here, the workload is already
       in fast local SRAM

cache.c supplies what the FVP example explicitly deferred to silicon: a
data-cache set/way sweep that reads CLIDR and CCSIDR and walks every set and
way the hardware reports, rather than assuming a geometry.  The FVP file notes
that this "belongs with the silicon bring-up where it can be verified against
the real cache geometry"; this is that.  The sweep matters because caches are
not architecturally guaranteed invalid out of reset, and enabling a write-back
data cache holding stale valid lines would evict them over live memory.

The effectiveness result is reported separately from the enable, and that
separation was earned.  The first version of this test passed on warm < cold and
printed "caches on and the workload got faster" for 609904 counts against
609686 -- a 0.036% difference that is measurement noise.  That criterion was
worthless and the PASS was misleading.  It now reports the gain as a fraction
and only claims a speedup above 10%.

No speedup here is a plausible result rather than a defect: both the code and
the data this workload touches live in RTU-local low-latency SRAM, close to core
speed already.  There is no slow memory on this board to demonstrate a cache
against -- DDR would be the place, and DDR is not initialised.  So the honest
claim is "enabled and harmless", not "enabled and beneficial".

cache_clean_all() is called before parking, and this is not optional.  With a
write-back data cache, values this image writes can sit dirty in cache where a
debugger reading SRAM cannot see them -- and the memory-resident progress
markers and fault records this bring-up depends on are read exactly that way.
Without the clean, a post-mortem read could report stale values and look like a
fault that never happened.

ThreadX still passes on the same configuration and the protection test still
faults correctly: write to the read-only code region takes exactly one write
fault at the written address and recovers.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>

* Made the cache benchmark actually measure the cache

The caches now show a real effect instead of noise:

    D line     = 64 bytes
    D ways     = 4
    D sets     = 64
    D bytes    = 0x4000    16 KB L1 data cache, read from CCSIDR
    bench wds  = 0x800     8 KB working set, half the cache
    counts off = 0x000D1B87   858503
    counts on  = 0x0009F515   652053
    gain/1000  = 0xF0         24% faster
    C4 PASS caches measurably faster (>=10%)

The previous benchmark could not have measured anything, and its 0.036%
"speedup" was noise.  Two things were wrong with it.

It used a static buffer in the RTU-local fast-data bank.  That memory is close
to core speed already, so caching it saves almost nothing -- there is no latency
to hide.  The benchmark now runs over the extended SRAM at S32Z_EXT_SRAM_BASE,
which the Reference Manual describes as NOT RTU-local, and mpu.c gains a sixth
region to map it Normal write-back and never executable.

And its working set was a guessed 4 KB constant.  It is now sized at run time
from CCSIDR to half the reported data cache, so it fits and is revisited every
pass.  A set larger than the cache would stream through and evict, showing
little benefit even over slow memory -- a guess could have produced a null
result for a reason that has nothing to do with whether the cache works.

24% on this loop is a believable figure rather than a suspiciously large one:
the workload is a store-heavy read-modify-write over a write-back cache, so part
of the cost is write traffic that still has to reach SRAM.

Useful by-product: the L1 data cache geometry is now read and printed rather
than assumed.  Nothing in the SoC reference manual gives it, and the set/way
invalidate sweep in cache.c depends on it being right.

ThreadX still passes and the protection test still faults correctly.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>

* Fixed the PRBAR field encoding and proved execute-never enforcement

program_region() shifted every PRBAR field one bit too far left: SH<<4,
AP<<2 and XN<<1, where the Cortex-R52 TRM (r1p3 figure 3-39, table 3-80)
places BASE[31:6], RES0[5], SH[4:3], AP[2:1] and XN[0].  The intended XN
therefore landed in AP[1] -- the EL0-access bit -- and no region was ever
execute-never.  On this board the core ran instructions straight out of
.data with LR_abt at 0x3178000c to prove it.

The write-to-read-only test passed throughout, which is why this survived:
under the old shift the AP value's low bit happened to land in the real
AP[2], the read-only bit, so permissions came out right by accident while
XN was silently discarded.  Only an instruction fetch from a region marked
non-executable could distinguish the two.

The AP macros in mpu.h go back to the architectural encoding, AP[2] for
read-only and AP[1] for EL0 access.  No calibration is needed; the values
were correct as published all along.

Verified on S32Z280 silicon: the data region now reads back PRBAR
0x31780001 with XN set, a write to the read-only code region faults with
DFSR 0xA0C, execution from the data region takes a prefetch abort with
IFSR 0x20C at 0x31780000, both faults recover, and the ThreadX demo still
reports 100 ticks with 20 preemptions.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>

* Corrected the same PRBAR encoding bug in the FVP MPU example

The FVP example carries the identical off-by-one shift that the S32Z280
bring-up exposed, so no region there was execute-never either: the data
region and the whole peripheral region were both freely executable, and
each also gained unintended EL0 access from the misplaced XN bit.

This also retires the "PRBAR.AP bit order is reversed" claim in mpu.h.
That note rested on a real measurement -- four regions, one per AP
encoding, privileged write attempted on each, writes faulting for 0b01 and
0b11 -- but the cause was the shift, not the bit order.  With AP written
into bits[3:2], its low bit lands in the real AP[2], the read-only bit, so
writes fault exactly when that bit is set.  The "high bit grants EL0
access" half of the conclusion was never tested; under the old shift that
bit landed in SH[0], programming a shareability the TRM calls
UNPREDICTABLE.  The architectural encoding needs no calibration.

demo_mpu.c gains the check that would have caught this: an instruction
fetch from the execute-never data region must take a prefetch abort.
Recovering from one cannot work the way the data-abort path does, since
skipping the faulting instruction is impossible when the instruction is
what could not be fetched, so entry.S gains a recoverable prefetch-abort
path that returns to a landing point recorded by mpu_try_execute.

Verified both ways.  All five FVP images pass, and the new check reports
prefetch aborts 0 -> 1.  Restoring the old shift for one run makes it fail
with 0 -> 0, so the check is not vacuous.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>

* Removed the unassemblable .arch directive from the S32Z280 example

GNU as accepts ".arch armv8-r"; LLVM's integrated assembler accepts no spelling
of it -- not armv8-r, not armv8r, not armv8-r+crc -- and stops with "Unknown
Arch: armv8-r". There is nothing to substitute, so the directive goes. The
architecture comes from -mcpu=cortex-r52 on the command line, which every
toolchain file passes, so it only restated it.

entry.S in this example never had one. The two equivalents in the FVP example are
handled separately, in the change that brings those images under the LLVM check.

Verified: both S32Z280 assembly sources now assemble with Arm Toolchain for
Embedded 22.1.0, and the GNU build of s32z280_boot.elf and s32z280_demo.elf is
unchanged with no warnings.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>

* Stopped read_identity.gdb reporting failure after a successful demo run

The script reads r52_identity, which only the boot image defines. The kernel demo
shares the same bsp_done breakpoint and the same boot_stage marker, so it is
convenient to point the same script at either image -- but against the demo the
lookup raised and gdb exited 1, after the demo had already printed
"PASS threads, tick and preemption all verified" over the console. A tool that
reports failure on success is worse than one that prints nothing.

The lookup is now guarded, and says which image it is looking at rather than
falling over. Everything after it is skipped when the structure is absent.

Verified against both images on S32Z280 silicon: the demo exits 0 and reports its
own PASS, and the boot image still prints the full identity report with MIDR
0x411FD133 and C3, C4, X2 and X4 all passing.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>
2026-08-12 10:25:35 -04:00
Frédéric Desbiens b0ad67bae9 Brought the Cortex-R52 examples under the LLVM check, and fixed two blockers (#604)
#600 added a line reporting which example builds the LLVM check passes over, and
cortex_r52 was on it: its examples are driven by CMake rather than by a
build_threadx.sh pair, so the linking stage never touched them. Covering them
turned up two reasons they could not have been built with anything but GNU.

.arch armv8-r has no portable spelling. GNU as accepts it, and LLVM's integrated
assembler rejects every variant -- armv8-r, armv8r, armv8-r+crc -- with "Unknown
Arch: armv8-r". There is nothing to substitute, so the directive is gone from
entry.S and tx_initialize_low_level.S; -mcpu=cortex-r52 already selects the
architecture, both toolchain files pass it, and the directive only restated it.
Worth noting where this hid: the assembly stage walks ports/*/gnu/src, so example
assembly had never been assembled by LLVM at all.

-Wl,--no-warn-rwx-segments is GNU ld only, added in binutils 2.39. ld.lld does
not warn about RWX segments and rejects the flag outright, failing the link with
"unknown argument". It is now selected on CMAKE_C_COMPILER_ID rather than spelled
into all six targets, and the reason it exists at all -- a bare-metal image has
one flat DRAM region and leaves access control to the MPU -- moves to the one
place that sets it.

cmake/cortex_r52_clang.cmake is the toolchain file. It names the tools as found
on PATH, which is what CI uses, then pins $HOME/toolchains if that directory
exists, mirroring how cortex_r52.cmake pins the GNU toolchain and for the same
reason. Falling back rather than requiring the pinned path keeps the file usable
on a machine that keeps clang elsewhere. THREADX_TOOLCHAIN stays "gnu": there is
no clang port directory, this builds the gnu sources with a different compiler,
which is what the whole check does for every other Arm port.

check_clang.sh gains a fourth stage for CMake-driven examples, and no longer
reports cortex_r52 as a gap. It reads the image list out of the generated ninja
graph rather than repeating it, so adding a target cannot escape the check, and
filters out the cmake_object_order_depends_target_* phonies -- counting those
reported ten images where there are five.

Verified with Arm Toolchain for Embedded 22.1.0, the version the workflow pins.
All five images link, and all five then run and pass on FVP_BaseR_AEMv8R:
boot_check, demo_m2, demo_m3, demo_threadx and demo_mpu. That is a step beyond
the AArch64 examples, which are link-verified only. The full check reports 711 of
711 assembly sources, 185 of 185 common C sources for each of nine cores, 42 of 42
script-driven examples and 5 of 5 CMake images, leaving only cortex_a5_smp,
cortex_a7_smp and cortex_a9_smp listed as having no driver.

GNU is unaffected: the same five images build with no warnings and the FVP test
suite passes 5 of 5.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>
2026-08-11 19:53:11 -04:00
Frédéric Desbiens 31fbe21d20 Removed developer machine paths from the shipped project files (#603)
The Arm Development Studio launch configurations and the IAR project files
carried absolute paths from the machines they were last opened on: four
individuals' home directories, a Broadcom support build tree, and directories
such as C:\release\threadx, C:\temp1702\tx and D:\threadx. They are published in
the repository and none of them resolves for anyone else.

In the launch files all of it is saved session state, which files that were never
opened in a debugger simply do not have:

  breakpoints                  72 files, saved breakpoints anchored to source
                               paths under cortex_a35 on one machine. Emptied
                               rather than deleted, matching the 27 launch files
                               that already carry an empty list.
  scripts_view_script_links    70 files, a scripts view cache. The script the
                               launch actually runs is named one line earlier
                               through ${workspace_loc:...}, which is portable.
  substitutePath               65 files, source lookup remapping. 30 map a path
                               to itself, and the rest point at one machine's
                               copy of libgloss or a build directory.
  TREE_NODE_PROPERTIES         39 files, which rows the variables view had
                               expanded.
  DebugCommandLine.History      2 files, the debug console command history,
                               including a typed absolute path.

The two IAR cases are not session state and are corrected rather than removed:

  IarchiveOutput               23 files. The librarian output path pointed at
                               another machine, so the library was written
                               outside the project. Set to ###Unitialized###,
                               which 86 other option blocks already use, letting
                               IAR derive $EXE_DIR$\$PROJ_FNAME$.a.
  IlinkIcfFile                  1 file. The linker configuration file is load
                               bearing, so the file name is kept and the path
                               made project relative, as 33 other option blocks
                               spell it.

Seven of the files are ports_arch templates, so the generators would otherwise
have copied the paths back.

Verified: all 162 launch and IAR project files in the tree parse as well-formed
XML afterwards, no tracked launch or project file mentions any of the four user
names, and scripts/check_ports.sh passes, so the templates and their generated
copies still agree.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>
2026-08-11 19:39:41 -04:00
Frédéric Desbiens c78c080139 Made the ARMv8-A debug launch configurations name their own core (#602)
Two identifiers in the Arm Development Studio launch configurations still said
A35 in every AArch64 port, because the generator's patch table could not reach
them.

The config database taxonomy id is spelt in lower case in the launch files,
/platform/armfvp/base_a35x4, but the search string read base_A35x4. Both
generators are case sensitive here, sed in update.sh and -creplace in
update.ps1, so the rule matched nothing and all 27 ports kept the A35 taxonomy
id while the platform name and model beside it named the right core. That the
rule exists at all shows the substitution was intended, and the ARMv7-A
generator does the same thing correctly, which is why its ports carry a per-core
ve_cortex_a<n>x1 id.

The SMP launch files name the activity "Cortex-A35x4 SMP" where the ThreadX ones
say "Debug Cortex-A35", so the existing activity rule reached the ThreadX ports
only and every SMP port advertised an A35 activity. Add a rule that matches the
" SMP" suffix, which also keeps it from rewriting the FVP model name that the
line above already handles.

Both changes are mirrored in update.ps1, which stays equivalent to update.sh.

Verified by regenerating: 50 launch files change and nothing else, 100 lines of
taxonomy id across 24 ThreadX and 26 SMP files, and 52 lines of activity name
across the 26 SMP files. No other attribute in those files moves, so the new
" SMP" rule does not touch the model name. The two Cortex-A35 ports are
untouched, as they must be, since substituting A35 for A35 is a no-op.
scripts/check_ports.sh passes, so the result is reproducible.

This cannot be exercised here: confirming that Arm Development Studio resolves
the per-core taxonomy ids needs Arm Development Studio. The change rests on the
platform name and model already naming the core, on the patch rule's existence,
and on the ARMv7-A ports having shipped per-core ids all along.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>
2026-08-11 16:20:48 -04:00
Frédéric Desbiens 96b1638fe4 Gave the Armv8-M examples a linkable sample and fixed what stopped them (#601)
The Cortex-M23, M33, M55 and M85 examples each shipped a build_threadx.sh with
no build_threadx_sample.sh, so scripts/check_clang.sh skipped all four at its
linking stage: the whole Armv8-M family had no example-link coverage. Adding the
missing script surfaced five separate reasons why none of them could have linked.

ports/cortex_m23/gnu/src/tx_initialize_low_level.S referenced
Image$$ARM_LIB_STACK$$ZI$$Limit and __Vectors, which are Arm toolchain
scatter-load names that no GNU linker defines. This is a GNU port, so it now
uses __RAM_segment_used_end__ and _vectors, as the Cortex-M33 version already
does. The Cortex-A ports mention Image$$ZI$$Limit only inside a comment; this
was a live relocation.

The Cortex-M23 crt0 needed unified assembler syntax. The Armv7-M file it derives
from carries no .syntax directive, so GNU as reads it in the legacy divided
syntax, where a Thumb data-processing instruction sets the flags whether or not
the mnemonic says so, and "mov r2, #0" assembles to 2200, MOVS. LLVM implements
unified syntax only, where those mnemonics mean the non-flag-setting forms that
Armv8-M Baseline does not have. Disassembling the Cortex-M4 object confirms GNU
already emits 2200 movs, 1a52 subs and 3001 adds, so spelling them out changes
no encoding. The flags carry meaning: crt0_memory_copy branches on the result of
"subs r2, r2, r1" and again on "subs r2, #1".

Cortex-M23 has no SVC_Handler to name in its vector table. Its library is built
-DTX_SINGLE_MODE_NON_SECURE, and tx_thread_schedule.S defines that handler only
when neither TX_SINGLE_MODE_SECURE nor TX_SINGLE_MODE_NON_SECURE is set, so the
SVCall slot takes __tx_BadHandler. The table also uses the CMSIS handler names
throughout, because that is what the Armv8-M ports export: the Armv7-M table
references __tx_SVCallHandler and __tx_SysTickHandler, which resolve to nothing
here.

The other three needed a C library. tx_thread_secure_stack.c calls malloc and
free, which pulls the allocator in, and the sample scripts already defined
SYSCALL_LIB for exactly that without ever passing it to the linker. Their linker
scripts now also provide end and _end, which newlib's libnosys _sbrk wants, and
__heap_start and __heap_end, which picolibc wants instead.

Cortex-M55 and M85 build with the hard-float ABI now, in both the library and
the sample. Arm Toolchain for Embedded ships no soft-float MVE multilib and says
so plainly: "No library available for MVE with soft-float ABI." The library and
the sample have to agree, and -mfloat-abi=hard is what check_clang.sh already
uses for these two cores in PORT_TARGET.

Verified with GNU 13.2.1 and Arm Toolchain for Embedded 22.1.0. Every port links
under both: Cortex-M23 at 206,136 and 312,636 bytes, M33 at 305,856 and 320,696,
M55 at 306,228 and 320,664, M85 at 306,240 and 320,668. check_clang.sh now
reports 42 of 42 example builds linking, up from 38, and no longer lists any port
as carrying build_threadx.sh without build_threadx_sample.sh. The images are
link-verified only and have not been executed, as with the AArch64 examples.

Only .sh drivers are added. Cortex-M23 has a build_threadx.bat with no sample
counterpart and the other three have no .bat at all; adding untested Windows
scripts belongs in its own change.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>
2026-08-11 14:00:54 -04:00
Frédéric Desbiens b87a62d218 Brought Cortex-A34 and the A78 SMP port under the ARMv8-A generator (#599)
ports/cortex_a34, ports_smp/cortex_a34_smp and ports_smp/cortex_a78_smp were
absent from the ARMv8-A generator's core list, so ports_arch never reached them
and scripts/check_ports.sh could not detect that they had drifted. They had.

The two Cortex-A34 ports sat two releases behind the shared sources, at 6.1.10
against 6.3.0. The difference is not only banners: tx_initialize_low_level.S
lacked the SUB x1, x1, #15 that precedes the BIC when the system stack pointer
is recorded, so the value stored was the incoming SP rather than the first
16-byte boundary below it. The Arm Development Studio example was missing
GICv3_aliases.h, which every other port's GICv3_gicc.h includes to reach the
interrupt controller registers through the stringify indirection.

The Cortex-A78 SMP port had never had its debug launch configuration patched at
all. It still named the A35 platform and model, so Debug Cortex-A35,
Base_A35x4 and FVP_Base_Cortex-A35x4 would have started an A35 model for an A78
port.

Add cortex_a34 to the core list. Cortex-A78 cannot go in the same list, because
the generator walks cores against port sets and would then create a
ports/cortex_a78 that the tree has never had; give it a separate SMP-only list
consulted only for the tx_smp port set. Both changes are mirrored in update.ps1,
which stays equivalent to update.sh.

Verified by regenerating: exactly these three port directories change, 116 files
modified and 13 added, and no already-covered core moves, so the core list was
the only thing holding them back. scripts/check_ports.sh passes, which now means
these three are checked for reproducibility for the first time.
scripts/check_clang.sh reports 38 of 38 example builds linked, the three new
ports included.

readme_threadx.txt is not added here. Only the two Cortex-A35 template ports
carry it; the other 23 AArch64 ports do not, so its absence from Cortex-A34 is
the tree's norm rather than drift, and supplying it everywhere is separate work.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>
2026-08-11 09:57:55 -04:00
Frédéric Desbiens 51ca412b36 Added build scripts for the AArch64 examples, which had none (#597)
The AArch64 examples could only be built through the Arm Development Studio
project files beside them. There was no script, so nothing in CI or on a
developer's machine could build them, and the sources they need were never
named anywhere: vectors.S, v8_aarch64.S and v8_utils.S were present but
unreferenced, which is why a hand written link failed on GetCPUID, GetAffinity,
InvalidateUDCaches and ZeroBlock. Those four are defined in v8_aarch64.S and
v8_utils.S, in the tree all along.

Add one pair of scripts, in ports_arch so every AArch64 port receives them.
Both derive the -mcpu value and the kernel source directory from the port
directory they sit in, so a single pair serves the twelve ThreadX ports and the
twelve SMP ports, the latter building against common_smp and picking up the C
sources those ports carry alongside the assembly. TOOLCHAIN=atfe selects Arm
Toolchain for Embedded in place of the GNU toolchain, as it does for the ARMv7
example scripts.

One symbol genuinely had no definition. startup.S calls
initialise_monitor_handles to open the standard file handles over a debugger
connection; the GNU toolchain provides it in libgloss through
--specs=rdimon.specs, while picolibc has no equivalent and neither does the
LLVM toolchain's semihosting library. semihost_stub.S supplies a weak no-op,
linked for that toolchain only, so a real definition always wins.

Extend scripts/check_clang.sh to cover ports_smp as well as ports, since the
example builds now exist there too.

Verified by building every AArch64 example with Arm Toolchain for Embedded:
twelve ThreadX ports at 314,744 to 315,256 bytes of text and twelve SMP ports
at 325,304 to 325,880. scripts/check_clang.sh now reports 35 of 35 example
builds linking with none failing, the twenty-four new ones plus the eleven that
already built. The images have not been executed: the sample
targets the Base platform peripheral addresses, which the available emulator
does not provide.

Cortex-A34, and the Cortex-A34 and A78 SMP ports, are left out. They are not in
the generator's core list, so they receive nothing from ports_arch and cannot be
checked for reproducibility either. Bringing them in rewrites 114 files in those
three directories, which deserves its own change.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>
2026-08-11 08:54:04 -04:00
Frédéric Desbiens 08eff8061c Made the Cortex-A12, A15 and A17 examples link with an LLVM toolchain (#596)
Those three sample scripts compiled crt0.S and reset.S but named neither on the
link line, and omitted -nostartfiles, so the toolchain was also free to link its
own startup. Under GNU that produced a working image; under an LLVM toolchain
picolibc's crt0 was pulled in and wanted __data_start, __data_source,
__data_size, __bss_size, __stack, __tls_base and __arm32_tls_tcb_offset, none of
which the linker script defines.

Defining picolibc's contract in the shared linker script was tried first and
abandoned: it reaches into ABI constants that cannot be verified here, and it is
unnecessary, because the in-tree crt0.S is already a complete startup for this
script. It sets up the stack and zeroes BSS between __bss_start__ and
__bss_end__, and .data carries no AT() so there is nothing to copy.

So the three scripts now pass -nostartfiles and name crt0.o and reset.o, which
is what the four sibling A profile cores already do and what these scripts were
evidently compiling those files for.

Both the old and the new GNU images contain the in-tree startup, __vectors from
reset.S and _mainCRTStartup from crt0.S, so the startup was already being used
through implicit startup file resolution rather than an explicit operand. How
that resolution happened without the objects being named is not accounted for
here, which is itself the argument for naming them: the same implicit behaviour
does not hold across toolchains, and that is why the LLVM link failed.

Add a readme to each of the three example directories. Their
tx_initialize_low_level.S is the generic ARMv7-A skeleton, 300 lines and
identical across all three, with no interrupt controller programming, no timer
and no vector table installation, where the A5, A7, A8 and A9 examples have all
three and ship the matching Versatile Express support files. These three
therefore demonstrate that the port builds; they will not receive a timer tick.
Nothing in the tree said so, which invites the assumption that they are
equivalent.

Verified with both toolchains for all three cores. GNU links at 41,276 bytes of
text, down from 41,768 because the unused toolchain startup is no longer
included, and Arm Toolchain for Embedded links at 37,982 where it previously
could not link at all. The resulting image is structurally sound: entry at
_start, __vectors at address zero, and a BSS range in RAM. It has not been
executed. scripts/check_clang.sh now links eleven of eleven example builds.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>
2026-08-10 17:41:23 -04:00
Frédéric Desbiens a8aebc5206 Completed the Cortex-M0 barriers and made its example build with both toolchains (#595)
Two unrelated Cortex-M0 gaps, both left over from earlier work.

The memory barriers from #523 reached the Cortex-M0 gnu port but not its ac6 or
iar siblings, in either the inline system return in tx_port.h or the assembly
routine. Both take the same GNU or IAR code path, and iar already carried the
entry barrier, so the missing pieces were the entry pair for ac6 and the barrier
after restoring the interrupt posture for both. All three tools now match.

The Cortex-M0 example could not link with any toolchain. cortexm0_crt0.S
references 23 linker script symbols and the script defined only 12 of them, so
__text_start__, __text_end__, __text_load_start__, the rodata and fast section
symbols, and the ctors and dtors load addresses were all unresolved. The
Cortex-M4 script defines all 23, including a .fast section with no content whose
symbols exist so that the startup copy is a no-op, and its comment says as much.
The Cortex-M0 script is brought to that same shape.

That left the example failing under LLVM only, on instructions that ARMv6-M can
encode just one way. The file declared .code 16 but no syntax mode, so GNU as
used the legacy divided syntax in which a plain add or sub sets the flags
implicitly, while LLVM implements unified syntax only and rejected the
non-flag-setting spelling. Declaring .syntax unified and writing movs, adds and
subs makes both assemblers agree, and the encodings GNU produces are byte
identical before and after, verified by disassembling both objects.

The Cortex-M0 example now links with GNU at 22,520 bytes of text and with Arm
Toolchain for Embedded at 22,866, so it comes off the list of examples not
expected to link and scripts/check_clang.sh now links eight of eight.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>
2026-08-10 17:34:13 -04:00
Frédéric Desbiens f3ab36dacc Made the example builds work with LLVM, and fixed four that were broken on Linux (#594)
* Made the example builds work with LLVM, and fixed four that were broken on Linux

The gnu example builds are the natural LLVM path: Arm Toolchain for Embedded is
LLVM based, consumes GNU ld linker scripts, and needs none of the scatter files
or Arm DS projects the ac6 examples carry. So rather than port the ac6 examples,
teach the gnu scripts to drive either toolchain.

Each script now selects the toolchain from a TOOLCHAIN variable that defaults to
gnu, so every existing invocation behaves exactly as before. TOOLCHAIN=atfe
switches the compiler, adds the target triple, passes the entry symbol through
to the linker rather than to the driver, and links the toolchain's own
semihosting library in place of --specs=nosys.specs, which is a GCC spec file
mechanism with no LLVM equivalent. That last choice avoids adding a syscall stub
source to every example.

The scripts are parameterised rather than duplicated. Copies of build scripts
would drift the first time one side was edited, which is the failure this
repository has just spent several changes recovering from.

Four sample scripts could not run on a case-sensitive filesystem at all. They
compiled MP_PrivateTimer.s and V7.s while the files on disk are
MP_PrivateTimer.S and v7.s, and the Cortex-A5 and A9 scripts named MP_GIC.s
where the file is MP_GIC.S. The link lines named V7.o accordingly. Corrected to
match the files, which is why the Cortex-A5, A7, A8 and A9 examples now build on
Linux where before they could not.

Extend scripts/check_clang.sh to link the example builds as well as compile the
sources, since compiling proves the sources parse while only linking exercises
entry symbols, linker scripts and the C library together.

Eight examples are listed as not expected to link, each with its reason, so the
gaps stay visible rather than being silently skipped. Five of them fail with the
GNU toolchain too and are therefore not LLVM problems: the Cortex-M0 example's
crt0 references __text_load_start__, __text_start__ and __text_end__, which its
linker script never defines, while the Cortex-M4 script defines the equivalents;
the arm9, arm11, Cortex-R4 and Cortex-R5 examples need newlib multilib variants
that are not present in every GNU toolchain packaging. The Cortex-A12, A15 and
A17 examples fail only with LLVM, because their link line omits -nostartfiles so
the toolchain's own crt0 is linked and wants picolibc's __data_start,
__data_source, __data_size and __bss_size, which their linker script does not
define.

Verified by building every example with both toolchains. Seven link with both:
Cortex-A5, A7, A8, A9, M3, M4 and M7. The GNU results are unchanged where they
worked before, and now also succeed for the four scripts with the case bug.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>

* Resolved the compiler path before running the example builds

The example stage runs each build script from inside its own directory, so a
relative path passed with --clang stopped resolving there and every example
build failed instantly. Local runs passed an absolute path and did not show it;
the CI job passes a path relative to the workspace root, which did.

Resolve the compiler to an absolute path once, before any directory change, and
print it so the toolchain in use is visible in the log.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>

* Parameterised the archiver as well, and stopped the check hiding failures

The toolchain selection covered the compiler but not arm-none-eabi-ar, which the
scripts invoke 628 times to assemble the library archive. A machine with an LLVM
toolchain and no GNU one therefore could not build any example, which is exactly
the situation in CI: the runner has no Arm GNU toolchain installed. Local runs
had one, so this only appeared once the job ran.

Select the archiver alongside the compiler, taking llvm-ar from beside clang in
the toolchain. The four scripts that call arm-none-eabi-ld directly are left
alone: they are arm9, arm11, Cortex-R4 and Cortex-R5, all already listed as not
expected to link, and their invocations are specific to GNU ld in ways that
parameterising would not resolve.

The check reported "example build produced no image" and then filtered the log
for lines containing "error", which hid the actual cause, since a missing tool
reports "command not found" or "No such file or directory". It now prints the
tail of the log. That filtering cost two CI round trips to diagnose something
the first run already knew.

Verified by shadowing arm-none-eabi-gcc, arm-none-eabi-ar, arm-none-eabi-ld and
the aarch64 equivalents with stubs that fail loudly, then running the whole
check: all 711 sources assemble, all eight profiles compile and all seven
example builds link without any GNU tool being invoked. The GNU default path
still produces an identical image. The diagnostics were confirmed by pointing
the archiver at a name that does not exist and checking that the reason appears.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>
2026-08-10 15:10:34 -04:00
Frédéric Desbiens 68eb205768 Made the Arm ports build with LLVM, and added a check that keeps them that way (#593)
The gnu ports are only ever built with GNU tooling, and GNU as accepts several
non-canonical forms that LLVM's assembler rejects. Nothing noticed, because
nothing built them with anything else. This matters beyond clang itself: Arm
Toolchain for Embedded is LLVM based and is the successor to Arm Compiler 6, so
these are the code paths ac6 users move onto.

Seven files needed changing, none of which alters the emitted code:

LDREX and STREX take no offset in A32 state; the #imm form is Thumb-2 only. GNU
as drops the redundant zero, LLVM rejects it. Removed from the Cortex-A5, A7 and
A9 SMP protect routines.

ARMv8-M Baseline has no flag-preserving MOV immediate, so GNU as already emits
MOVS. Writing MOVS in the two Cortex-M23 sources says what the assembler was
doing anyway. One of them sits in a branch only compiled for the single mode
secure configurations, which is why it had never surfaced.

The Cortex-M0 schedule routine wrote LDR r0, =#0x10000000 with a stray hash,
which its own sibling file already wrote correctly.

The Cortex-M0 system return routine selected the numbered subsection .text 32,
which makes LLVM place the constant pool beyond the range a Thumb-1 PC relative
load can reach. Plain .text fixes it and GNU accepts either form. The reason is
recorded in the file, since 32 files pair a numbered subsection with a literal
pool load and the rest only escape because Thumb-2 and A32 have far more range.

Add scripts/check_clang.sh, which assembles every Arm gnu port source and
compiles the common C sources for one core per architecture profile, and a
clang_check workflow that installs Arm Toolchain for Embedded and runs it. The
toolchain version is pinned and checksum verified, for the same reason the
runner image is pinned.

The port directory to target mapping in that script is explicit rather than
prefix matched. Prefix matching is what makes cortex_a5 also match cortex_a53
and cortex_a55, which are AArch64, and assembling those as ARM32 produces
hundreds of misleading errors; that mistake cost real time while measuring this,
so the reason is recorded next to the table.

Verified with Arm Toolchain for Embedded 22.1.0: 711 of 711 assembly sources
assemble and 185 of 185 C sources compile for all eight profiles, against 6
assembly failures before the change. arm-none-eabi-gcc still assembles all 315
ARM32 sources, so nothing regressed for GNU. The check was confirmed to fail
when any one of the fixes is reverted.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>
2026-08-10 11:40:54 -04:00
Frédéric Desbiens f23a1807a2 Added bash A profile update scripts and restored ports_arch as their source (#592)
The ARMv7-A and ARMv8-A ports are generated by update.ps1, which needs
PowerShell, so the cortex-a job in ports_arch_check ran on a Windows image and
nobody could reproduce it locally on Linux. Add update.sh beside each
update.ps1, with the same cores, compilers, copy sets and patches, and move the
job to the same Linux image as everything else.

The bash scripts were checked against the PowerShell ones by comparing what
each reports as drifted. They agree exactly on the 63 files the Windows job
last reported, and differ on 12 more, which turn out to be a defect in
update.ps1 rather than in the port. Its two .cproject patterns are written as
'value=`"cortex-a7`"' with backticks that survive into the pattern, so that
replacement has never matched, while the neighbouring Cortex-A7.NoFPU pattern
has no backticks and always worked. The result is that the AC6 example builds
for the A5, A8, A9, A12, A15 and A17 cores name cortex-a7 as their CPU while
their FPU string is correct. The bash scripts do what the PowerShell ones
intended, so regenerating corrects those twelve files.

Restore ports_arch as the source for the rest. The implementation of
_tx_thread_smp_time_get from #555 was applied to the twenty four generated SMP
ports and never to ports_arch, which still held MOV x0, #0 with a FIXME
comment, so regenerating would have replaced a working generic timer read with
a stub. That implementation now lives in the source. The remaining differences
are cosmetic and resolve in favour of the source: a trailing blank line in 38
copies of tx_thread_schedule.S and comment spacing in one tx_port.h.

Note that the Cortex-A VFP fix is already present in ports_arch and was never
at risk, contrary to what the description of the port consistency checks change
said before this was measured.

Extend scripts/check_ports.sh to run the A profile generators too, and make it
fail when a generator fails or is missing rather than reporting a clean tree,
which would have been a false pass.

Pin every workflow to ubuntu-24.04. ubuntu-latest already resolves to that
image, so nothing changes today, but a future migration becomes a deliberate
commit rather than something that happens underneath the -m32 builds.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>
2026-08-09 10:55:29 -04:00
Frédéric Desbiens eb4ec4e3b5 Restored ports_arch as the source of truth for the Cortex-M ports (#590)
The Cortex-M ports under ports/ are generated. scripts/copy_armv7_m.sh copies
one tx_port.h and the per tool sources to fifteen M3, M4 and M7 targets, and
scripts/copy_armv8_m.sh does the same for nine M33, M55 and M85 targets. The
ports_arch_check workflow runs both scripts and fails if the tree is not
reproducible, so those copies are meant never to be edited directly.

They were. Every Cortex-M fix since #523 was applied to the generated copies
and not to the source, so the source fell behind and the check went red:
running the three scripts on dev changes 35 files. The check triggers only on
pull requests targeting master, which is why nothing caught it while the fixes
were merged into dev.

Left alone, the next run of these scripts would have reverted three separate
pieces of work: the memory barriers and clobbers from #523, the correction of
the IAR assembly header to use the assembler's own comment syntax, and the move
of tx_initialize_low_level.S into example_build for the M33, M55 and M85 GNU
ports from #514.

Bring the sources up to what the ports carry today, and regenerate. Two
behavioural changes come with that, both deliberate. The barriers from #523
reach the ac5 and keil variants of M3, M4 and M7, which were outside the scope
of that fix and never received it. The barrier that follows restoring the
interrupt posture, which #523 gave only to the GNU ports because GNU was the
only toolchain that could be tested, now applies to every tool; the identical
asm statement already shipped in the AC6 and IAR ports, so this adds a pipeline
flush rather than any new compiler exposure.

Regenerating also drops a stray #endif at the end of the Cortex-M85 IAR
tx_port.h, added by #523, which left that header with one more #endif than #if
and unable to compile. Every other ARMv8-M port was balanced.

Verified that the scripts are idempotent afterwards, that ports_arch_check
would pass, that no port loses a barrier or a clobber, that every regenerated
header is preprocessor balanced, and that every Cortex-M port covered by the
two scripts now carries the entry barrier.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>
2026-08-09 10:42:54 -04:00
Frédéric Desbiens cbdf924d6b Removed the duplicated function body in the Cortex-M4 AC6 port (#589)
_tx_thread_system_return_inline() in the Cortex-M4 AC6 tx_port.h was followed
by a second, orphaned copy of its own body. The copy had no function header, so
it declared interrupt_save at file scope and then placed statements there,
which does not compile. It is also the older version of the body, without the
dsb and isb barriers, so it was left behind rather than intended: the barriers
were added by commit 33efad3f and the previous text was not removed.

Delete the orphaned copy. What remains is the same body every sibling port
carries: after this change ports/cortex_m4/ac6/inc/tx_port.h differs from
ports/cortex_m4/iar/inc/tx_port.h and ports/cortex_m7/ac6/inc/tx_port.h only in
the port name in the banner and the version string, as it should.

Verified by compiling the function in isolation, which fails on the file scope
statements before the change and is clean afterwards, and by a structural scan
of all 208 tx_port.h files in the repository confirming this was the only
occurrence.

Fixes https://github.com/eclipse-threadx/threadx/issues/569

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>
2026-08-09 10:12:09 -04:00
Frédéric Desbiens f84dd3d2aa Added Cortex-R52 port with Armv8-R AEM FVP example build (#579)
Added a ThreadX port for Arm Cortex-R52 with the GNU toolchain

Adds ports/cortex_r52/gnu together with a CMake build, an example build for the
freely available Armv8-R AEM FVP, and an automated test suite.

The port is EL2-aware by construction.  Cortex-R52 always implements EL2 and
resets into it, so the reset path configures EL2, installs both the EL2 and EL1
vector tables, and only then drops to EL1 to run the kernel.  Keeping that
structure from the start lets partitioning work reuse the boot path rather than
replace it; TX_R52_BOOT_AT_EL1 skips the EL2 stage where a vendor monitor has
already dropped privilege.

This is also the first R-profile port in the tree with a working CMake build.
cmake/cortex_a9.cmake exists but ports/cortex_a9/gnu/CMakeLists.txt is empty, so
no A- or R-profile port could be built this way before.

Contents:

  - Kernel port: 16 assembly sources plus tx_port.h, seeded from the
    Cortex-R5/GNU port.
  - Build: cmake/cortex_r52.cmake and the port CMakeLists.txt, with soft/hard
    float, VFP, FIQ and IRQ/FIQ nesting options.
  - Example BSP: EL2 to EL1 boot, GICv3, generic timer, PMSAv8-R MPU,
    semihosting and PL011 consoles.
  - Tests: six images registered with CTest, each judging itself and
    terminating the model.
  - tx_port_offset_check.c: compile-time assertions on the TX_THREAD offsets
    the assembly reaches by hard-coded displacement.  This is the same defect
    class fixed for Cortex-R4/R5 in #578; nothing in the toolchain ties those
    literals to the C structure.

Two facts were established by experiment rather than taken from documentation,
and are recorded in the code and the readme because both are traps:

  - PRBAR.AP bit order is reversed relative to th
    AArch64 macro set: the low bit is read-only and the high bit grants EL0
    access.  Programming four disjoint regions, one per encoding, and
    attempting a privileged write to each gave 0b
    and 0b10 allowed.  Using the AArch64 ordering
    as read-only and silently accept writes, because region coverage is still
    enforced: an unmapped address faults while a "read-only" region does not.
  - The generic timer PPI is INTID 30, recorded from ICC_IAR1 after enabling
    the whole PPI range 25-31, rather than assume

Model behaviour that a silicon port must revisit: the FVP leaves CNTFRQ at zero
with the system counter stopped, so the BSP programs both; CNTHCTL.PL1PCTEN,
CNTHCTL.PL1PCEN and ICC_HSRE must be set at EL2 or EL1 accesses trap; and
tx_thread_vfp_enable() sets only a per-thread software flag, so enabling the FPU
hardware (CPACR, FPEXC.EN) is the board support package's responsibility, not
the kernel's.  The FVP reports MIDR 0x410FD0F0, an architecture envelope model
rather than a Cortex-R52, so it validates architecture and not implementation.
Nothing in the port is gated on MIDR.

Changes outside ports/cortex_r52, three and all small: cmake/cortex_r52.cmake is
a new toolchain file; CMakeLists.txt gains enable_testing() at the top level,
without which add_test() in a subdirectory generat
the root never references, so ctest reports no tests from the build root; and
.gitignore covers build directories and __pycache__.

Verification: all six images build warning-free a
FVP_BaseR_AEMv8R in three configurations -- protection off, protection and
caches on, and both together with hard-float VFP.  Six build-option
combinations build clean and pass the tick-and-preemption demo at run time.

The tests assert behaviour rather than configuration, which is what caught the
problems above: the cooperative demo asserts the order of execution, because
counting alone cannot distinguish working context switches from one thread
running to completion, and the MPU test provokes real faults, because reading
SCTLR back only proves a bit was set.

The 96-test regression suite is host-side and pas
configurations on the Linux port.  It is not cross-run here: it validates
portable kernel logic, while the port-specific risk is the assembly, which the
FVP images exercise.  Structural coverage is therefore not claimed.

Deliberate deviations: passing a string literal to tx_thread_create reports a
discarded const qualifier from common/inc/tx_api.
CHAR *; demo_threadx.c keeps the shipped sample's int main() so the demo body
stays byte-identical to it; and the floating-point test compares exactly on
purpose, since a tolerance would mask a restored
wrong.

Not included: modules support, split-mode SMP and
support. The example targets the FVP only, and NXP S32Z280 bring-up is
separate work; the readme flags what to re-verify there.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>
2026-08-08 08:00:01 -04:00
Frédéric Desbiens 2baae7c57f Fixed VFP issues on Cortex-R4 and R5 ports (#578)
* Fixed missing VFP thread extension on Cortex-R4 and R5 ports

Building cortex_r4/gnu, cortex_r5/gnu or cortex_r5/ac6 with
TX_ENABLE_VFP_SUPPORT corrupts memory. The assembly in
tx_thread_schedule, tx_thread_system_return and tx_thread_context_restore
reads and writes a per-thread VFP enable flag as [thread, #144], but every
TX_THREAD_EXTENSION in these ports' tx_port.h was empty, so no such member
existed.

Offset 144 in the resulting TX_THREAD is tx_thread_filex_ptr, so the
damage runs both ways:

  - tx_thread_vfp_enable() stores 1 into tx_thread_filex_ptr, after which
    FileX dereferences 0x1;
  - conversely, once FileX sets that pointer the context switch reads it as
    "floating point enabled" and starts pushing about 132 bytes of
    floating-point context onto a thread stack never sized for it, then
    restores unrelated data into the D registers.

sizeof(TX_THREAD) is 180 on these ports, so 144 is a live member rather
than padding past the end of the structure.

What makes this dangerous is that it is silent. The defect was reproduced
at runtime by reverting the Cortex-R52 port -- which inherited the same
assembly and the same hard-coded 144 from the R5 port -- to this state and
running its floating-point demo on the Armv8-R AEM FVP. Every
floating-point value was still preserved exactly and no corruption was
reported across interrupts, because a non-zero filex_ptr reads as "enabled"
and the context switch dutifully saves and restores. The only visible
damage was tx_thread_filex_ptr reading 0x00000001. In other words the
feature you enabled appears to work, and what breaks is an unrelated
pointer that nothing notices until FileX is introduced. With the field
present the same demo reports the sentinel intact.

This appears to be drift rather than a deliberate limitation. All fourteen
Armv7-A port and toolchain combinations define the field and contain the
VFP code paths. The R-profile family is inconsistent in both directions:
these three have the code paths without the field, while cortex_r4/ac5,
cortex_r4/ac6, cortex_r4/iar, cortex_r5/ghs, cortex_r5/iar, cortex_r7/ghs
and cortex_r8_smp/ac5 define the field but contain no VFP code paths.

The fix follows the Armv7-A ports exactly: TX_THREAD_EXTENSION_2 carries
tx_thread_vfp_enable, and tx_thread_vfp_enable/disable are declared. The
field is defined unconditionally rather than under TX_ENABLE_VFP_SUPPORT
because the offset is hard-coded in assembly, so a conditional member
would shift every following field and be correct in only one
configuration. No assembly changes are needed: 144 is already correct once
the member exists.

Verified with GCC 14.3: on all three ports tx_thread_vfp_enable now lands
at exactly offset 144, matching the assembly, with tx_thread_filex_ptr
moved to 148. The library builds cleanly for cortex_r4/gnu and
cortex_r5/gnu both with and without TX_ENABLE_VFP_SUPPORT, and the VFP
save and restore instructions appear in the port assembly only when it is
requested. cortex_r5/ac6 is verified by offset and inspection only, as
that toolchain was not available here. Runtime verification was performed
on Armv8-R as described above rather than on R4/R5 silicon; upstream QEMU's
xlnx-zcu102 machine holds its Cortex-R5F cores in reset, so no R5 target
was available.

ABI note for release documentation: adding the member moves
tx_thread_filex_ptr and everything after it by four bytes and grows
TX_THREAD from 180 to 184 bytes. This is the layout the Armv7-A ports
already have, so the change aligns R-profile with A-profile rather than
introducing a new one, but kernel awareness and TraceX tooling that
hard-codes offsets will need rebuilding.

Follow-up worth considering separately: nothing in the toolchain ties the
literal 144 in the assembly to the C structure, which is what allowed this
to go unnoticed. A compile-time assertion per port turns any recurrence
into a build failure -- when the experiment above reverted the field, that
assertion failed the build before a corrupting binary could be produced.
ports/cortex_r52/gnu/src/tx_port_offset_check.c is a working reference.


* Added compile-time offset checks to the Cortex-R4 and R5 ports

Nothing in the toolchain connects the structure offsets hard-coded in the
port assembly to the C definition of TX_THREAD, which is what allowed the
missing VFP thread extension to go unnoticed. These files assert the
offsets that the context-switch path depends on, so a recurrence becomes a
build failure instead of memory corruption discovered later at runtime.

Three offsets are asserted: the VFP enable flag at 144, the thread stack
pointer at 8 and the run counter at 4. The stack pointer and run counter
precede every extension macro in TX_THREAD, so they are stable by
construction. Offset 144 was checked against the build options that could
plausibly move it -- stack checking, event trace, event logging,
performance info and TX_NOT_INTERRUPTABLE -- and is unchanged by all of
them, because the only conditional member nearby guards
tx_thread_filex_ptr, which follows the extension, and
TX_THREAD_USER_EXTENSION appears much later in the structure. The
assertions therefore cannot misfire on a legitimate configuration.

C99 has no _Static_assert, so a negative array dimension is used. Each
file compiles clean under -std=c99 -pedantic -Wall -Wextra and emits zero
bytes of code or data.

Verified that the checks actually catch regressions rather than merely
compiling: asserting a deliberately wrong offset is rejected on all three
ports, and removing the VFP field again fails the build outright with a
message naming the missing member.

These ports have no CMake build of their own, so the files take effect
only in builds that compile everything under src/. That is still
worthwhile given they cost nothing and emit nothing. Extending the same
technique to the remaining ports is deliberately left as separate work: it
requires reading each port's assembly to attribute every hard-coded
literal to the right structure, and copying assertions without that
analysis would risk asserting wrong offsets.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>
2026-08-06 10:05:33 -04:00
Frédéric DesbiensandCodex a33f6efc48 Updated Cortex-R4 Thumb bit immediates (#565)
Use explicit immediate syntax when testing the Thumb bit in AC6 Cortex-R4 stack build assembly.

Co-authored-by: Codex <codex@openai.com>
2026-06-29 16:22:52 -04:00
Frédéric DesbiensandCodex 3fcfb4e4c9 Updated Cortex-M BASEPRI zero immediates (#564)
Use explicit immediate syntax when clearing BASEPRI in GNU and AC6 Cortex-M scheduler assembly.

Co-authored-by: Codex <codex@openai.com>
2026-06-29 16:07:12 -04:00
d9e7dfea89 Add SysTick counter reset in Cortex-M ports (#561)
* Add SysTick counter reset in Cortex-M ports

The SysTick counter value (SYST_CVR @0xE000E018) is indeterminate after
reset. Without clearing it prior to enabling the counter, the first tick
interval becomes unpredictable.

* Fixed missing comment and added generated-by header in Cortex-M0/AC6 port

Added the missing inline comment on the LDR r1, =0 instruction
(Build value for SysTick reset) and the required AI-generated
attribution comment under the copyright header.

---------

Co-authored-by: Frédéric Desbiens <frederic.desbiens@eclipse-foundation.org>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
2026-06-24 12:16:51 -04:00
franco 859c098747 Fix nested comment warning in RX GCC ports (#550)
The RX GCC assembly port contains an unclosed C-style comment in tx_thread_context_save.S. Because .S files are passed through the C preprocessor before assembly, the nested comment can trigger GCC warnings.

Close the affected comment block without changing assembly instructions or runtime behavior.

Signed-off-by: FranCDoc <fchiesadoc@gmail.com>
2026-06-16 10:26:26 -04:00
Frédéric DesbiensandCopilot df30b8b96e Release 6.5.1.202602a preparation (#547)
* Updated version number constants

* Updated port version strings

---------

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
2026-06-08 16:59:04 +02:00
Frédéric Desbiens 5a07bdac35 Fix/issue 545 basepri endif (#546)
* Fixed #else replaced with #endif in tx_port.h for cortex_m3/m4/m7 gnu/ac6/iar ports

In the __set_basepri_value/#ifdef TX_PORT_USE_BASEPRI block, an #else
directive was incorrectly replaced with #endif in a prior commit.
This caused the TX_PORT_USE_BASEPRI guard to close prematurely and
left __enable_interrupts unconditionally visible (or triggered an
orphaned #endif / missing #endif error at compile time).

Affected ports: cortex_m3/ac6, cortex_m3/iar, cortex_m4/ac6,
cortex_m4/gnu, cortex_m4/iar, cortex_m7/ac6, cortex_m7/gnu,
cortex_m7/iar.

For cortex_m3/gnu and cortex_m4/gnu the fix restores the #else and
the existing second #endif now correctly closes the block.
For the ac6/iar variants of m3/m4 and all m7 variants, the #else is
restored and a missing closing #endif is added after __enable_interrupts.

Also adds Linux shell build scripts (build_threadx.sh and
build_threadx_sample.sh) for the cortex_m3/gnu, cortex_m4/gnu, and
cortex_m7/gnu example_build directories as Linux equivalents of the
existing .bat files.


* Fixed missing linker script symbols in cortex_m4/gnu example_build

cortexm4_crt0.S references several symbols that were absent from
sample_threadx.ld, causing undefined-reference linker errors when
building the sample:

- __text_load_start__, __text_start__, __text_end__
- __rodata_load_start__, __rodata_start__, __rodata_end__
- __fast_load_start__, __fast_start__, __fast_end__
- __ctors_load_start__, __dtors_load_start__

Changes:
- Added __text_start__/__text_end__ bounds to the .text section and
  __text_load_start__ via LOADADDR(.text).
- Moved .rodata out of .text into its own section with start/end/load
  
- Added __ctors_load_start__ and __dtors_load_start__ markers within
  .text (load address == VMA since the section is XIP in FLASH; the
  crt0 copy call becomes a no-op).
- Added an empty .fast section in RAM with __fast_load_start__ pointing
  to __fast_start__ so the crt0 fast-copy call is a no-op.


* Added Linux build scripts and fixed path bug in cortex_m23 for all ports changed between v6.5.0 and v6.5.1

Added build_threadx.sh (and build_threadx_sample.sh where applicable)
as Linux equivalents of the Windows .bat scripts for all GNU-toolchain
ports touched between v6.5.0.202601_rel and v6.5.1.202602_rel:

  arm9, arm11, cortex_a5/a7/a8/a9/a12/a15/a17,
  cortex_m0, cortex_m23, cortex_r4, cortex_r5

For cortex_m33/m55/m85 (which had no .bat equivalent), build_threadx.sh
was written from scratch using the port CMakeLists.txt source lists and
the correct CPU flags (-mcpu=cortex-m33/m55/m85 -mthumb).

Also fixed a pre-existing bug in cortex_m23/gnu/example_build/
build_threadx.bat (and the generated .sh): tx_thread_stack_error_handler.c
and tx_thread_stack_error_notify.c were referenced as ../src/ (port
directory) instead of ../../../../common/src/ where they actually live.

All 16 newly added build_threadx.sh scripts were verified to compile
successfully with arm-none-eabi-gcc 13.2.1.

---------
Closes #545
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
2026-06-08 16:51:08 +02:00
Frédéric DesbiensandCopilot 730b61874b Added copyright headers to files missing them
Applied the standard MIT license header to all project-owned C, header,
assembly, shell, and Python files that were missing a copyright notice.
Third-party, toolchain startup, and auto-generated files were excluded.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
2026-06-06 21:48:06 +02:00
Frédéric DesbiensandCopilot de1c6e9bbe Release 6.5.1.202602 preparation (#543)
* Updated version number constants
* Updated port version strings

---------

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
2026-06-03 16:55:01 -04:00
Frédéric DesbiensandCopilot d4b9448f84 Added riscv-none-elf-rv32imc toolchain file for xPack (risc-v32) (#539)
Add cmake/riscv-none-elf-rv32imc.cmake targeting the xPack
riscv-none-elf-gcc toolchain with rv32imc_zicsr/ilp32 ABI for
bare-metal CORE-V MCU builds.

Update cmake/riscv32-unknown-elf-rv32imc.cmake to correctly target
rv32gc/ilp32d (matching riscv-collab riscv32-elf ABI) for QEMU
regression tests.

Update cmake/riscv64-gcc-rv32imc.cmake compat alias to include
the new riscv-none-elf-rv32imc.cmake.

Update CORE-V MCU example_build: build.sh exports xPack PATH,
install_deps.sh downloads xPack 15.2.0-1, README.md reflects new
toolchain name/path.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
2026-05-27 17:06:37 -04:00