If atomic_try_cmpxchg_xxxx runs on LL/SC architectures (e.g.ARMv7,
ARMv8, RISC-V), the weak CAS expands to a single LDREX/STREX pair.
If the CPU takes an IRQ/FIQ/SVC between the two instructions,
hardware performs an implicit CLREX and the following STREX returns
1, therefore atomic_try_cmpxchg_xxxx return failure even though
*addr* still holds the expected value.
So let's retry atomic_try_cmpxchg_xxxx in this case.
Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
The fast path can be used also for counting semaphores when the priority
inheritance is disabled.
Signed-off-by: Jukka Laitinen <jukka.laitinen@tii.ae>
This enables the mutex fast path for nxsem_wait, nxsem_trywait and nxsem_post also when
the priority inheritance is enabled.
Signed-off-by: Jukka Laitinen <jukka.laitinen@tii.ae>
This puts the mutex support fully inside nxsem, allowing
locking the mutex and setting the holder with single atomic
operation.
This enables fast mutex locking from userspace, avoiding taking
critical_sections, which may be heavy in SMP and cleanup
of nxmutex library in the future.
Signed-off-by: Jukka Laitinen <jukka.laitinen@tii.ae>
This reverts commit 300992203a to
fix a problem with `esp32-devkitc:blewifi`, which fails to boot up
if `CONFIG_DEBUG_ASSERTIONS=y`.
Introduced by https://github.com/apache/nuttx/pull/16176 with the
following description:
> The DEBUGASSERTS in nxsem_wait and nxsem_trywait are
non-functional, they don't check anything. These were broken in
previous commits.
The above statements are not valid. Originally, there was no
problem calling `nxsem_trywait` from the interrupt and the
`DEBUGASSERT` simply checked a corner case: if ran from the
interrupt context, the current (interrupted) task may be the idle
task. This case is allowed only if called from an interrupt and
that's what the original commit checks with:
```
DEBUGASSERT(!OSINIT_IDLELOOP() || !sched_idletask() ||
up_interrupt_context());
```
The DEBUGASSERTS in nxsem_wait and nxsem_trywait were non-functional, they
didn't check anything.
Signed-off-by: Jukka Laitinen <jukka.laitinen@tii.ae>
This avoids unnecessary syscalls in memory protected builds, when mutex
lock/unlock can be done with only atomic counter access
Signed-off-by: Jukka Laitinen <jukka.laitinen@tii.ae>
Most tools used for compliance and SBOM generation use SPDX identifiers
This change brings us a step closer to an easy SBOM generation.
Signed-off-by: Alin Jerpelea <alin.jerpelea@sony.com>
This moves all the public POSIX semaphore functions into libc and with
this most of the user-space logic is also moved; namely cancel point and
errno handling.
This also removes the need for the _SEM_XX macros used to differentiate
which API is used per user-/kernel mode. Such macros are henceforth
unnecessary.
hujun5
Xiang Xiao
Jukka Laitinen
Tiago Medicci Serrano
Alin Jerpelea
Ville Juven