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arch/arm/src/armv7-a: Port the SMP change by Masayuki Ishikawa to the ARMv7-A family.

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This commit is contained in:
Gregory Nutt
2018-02-14 08:36:34 -06:00
parent d7fae340c1
commit 3ddea73dc1
2 changed files with 53 additions and 48 deletions
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arch/arm/src/armv7-a/arm_schedulesigaction.c
+52 -47
View File
@@ -1,7 +1,7 @@
/**************************************************************************** /****************************************************************************
* arch/arm/src/armv7-a/arm_schedulesigaction.c * arch/arm/src/armv7-a/arm_schedulesigaction.c
* *
* Copyright (C) 2013, 2015-2017 Gregory Nutt. All rights reserved. * Copyright (C) 2013, 2015-2018 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org> * Author: Gregory Nutt <gnutt@nuttx.org>
* *
* Redistribution and use in source and binary forms, with or without * Redistribution and use in source and binary forms, with or without
@@ -116,7 +116,7 @@ void up_schedule_sigaction(struct tcb_s *tcb, sig_deliver_t sigdeliver)
if (tcb == this_task()) if (tcb == this_task())
{ {
/* CASE 1: We are not in an interrupt handler and a task is /* CASE 1: We are not in an interrupt handler and a task is
* signalling itself for some reason. * signaling itself for some reason.
*/ */
if (!CURRENT_REGS) if (!CURRENT_REGS)
@@ -133,7 +133,7 @@ void up_schedule_sigaction(struct tcb_s *tcb, sig_deliver_t sigdeliver)
* *
* Hmmm... there looks like a latent bug here: The following logic * Hmmm... there looks like a latent bug here: The following logic
* would fail in the strange case where we are in an interrupt * would fail in the strange case where we are in an interrupt
* handler, the thread is signalling itself, but a context switch * handler, the thread is signaling itself, but a context switch
* to another task has occurred so that CURRENT_REGS does not * to another task has occurred so that CURRENT_REGS does not
* refer to the thread of this_task()! * refer to the thread of this_task()!
*/ */
@@ -166,7 +166,7 @@ void up_schedule_sigaction(struct tcb_s *tcb, sig_deliver_t sigdeliver)
/* Otherwise, we are (1) signaling a task is not running from an /* Otherwise, we are (1) signaling a task is not running from an
* interrupt handler or (2) we are not in an interrupt handler and the * interrupt handler or (2) we are not in an interrupt handler and the
* running task is signalling some other non-running task. * running task is signaling some other non-running task.
*/ */
else else
@@ -222,7 +222,7 @@ void up_schedule_sigaction(struct tcb_s *tcb, sig_deliver_t sigdeliver)
cpu = tcb->cpu; cpu = tcb->cpu;
/* CASE 1: We are not in an interrupt handler and a task is /* CASE 1: We are not in an interrupt handler and a task is
* signalling itself for some reason. * signaling itself for some reason.
*/ */
if (cpu == me && !CURRENT_REGS) if (cpu == me && !CURRENT_REGS)
@@ -238,51 +238,36 @@ void up_schedule_sigaction(struct tcb_s *tcb, sig_deliver_t sigdeliver)
* CPU. In the former case, we will have to PAUSE the other CPU * CPU. In the former case, we will have to PAUSE the other CPU
* first. But in either case, we will have to modify the return * first. But in either case, we will have to modify the return
* state as well as the state in the TCB. * state as well as the state in the TCB.
*
* Hmmm... there looks like a latent bug here: The following logic
* would fail in the strange case where we are in an interrupt
* handler, the thread is signalling itself, but a context switch
* to another task has occurred so that CURRENT_REGS does not
* refer to the thread of this_task()!
*/ */
else else
{ {
/* If we signalling a task running on the other CPU, we have /* If we signaling a task running on the other CPU, we have
* to PAUSE the other CPU. * to PAUSE the other CPU.
*/ */
if (cpu != me) if (cpu != me)
{ {
/* Pause the CPU */
up_cpu_pause(cpu); up_cpu_pause(cpu);
}
/* Save the return lr and cpsr and one scratch register /* Wait while the pause request is pending */
* These will be restored by the signal trampoline after
* the signals have been delivered.
*/
tcb->xcp.sigdeliver = sigdeliver; while (up_cpu_pausereq(cpu))
tcb->xcp.saved_pc = CURRENT_REGS[REG_PC]; {
tcb->xcp.saved_cpsr = CURRENT_REGS[REG_CPSR]; }
/* Increment the IRQ lock count so that when the task is restarted, /* Now tcb on the other CPU can be accessed safely */
* it will hold the IRQ spinlock.
*/
DEBUGASSERT(tcb->irqcount < INT16_MAX); /* Copy tcb->xcp.regs to tcp.xcp.saved. These will be restored
tcb->irqcount++; * by the signal trampoline after the signal has been delivered.
*/
/* Handle a possible race condition where the TCB was suspended tcb->xcp.sigdeliver = sigdeliver;
* just before we paused the other CPU. The critical section tcb->xcp.saved_pc = tcb->xcp.regs[REG_PC];
* established above will prevent new threads from running on tcb->xcp.saved_cpsr = tcb->xcp.regs[REG_CPSR];
* that CPU, but it will not guarantee that the running thread
* did not suspend itself (allowing any threads "assigned" to
* the CPU to run).
*/
if (tcb->task_state != TSTATE_TASK_RUNNING)
{
/* Then set up to vector to the trampoline with interrupts /* Then set up to vector to the trampoline with interrupts
* disabled * disabled
*/ */
@@ -292,23 +277,26 @@ void up_schedule_sigaction(struct tcb_s *tcb, sig_deliver_t sigdeliver)
} }
else else
{ {
/* Then set up to vector to the trampoline with interrupts /* tcb is running on the same CPU */
* disabled
/* Save the return PC, CPSR and either the BASEPRI or PRIMASK
* registers (and perhaps also the LR). These will be
* restored by the signal trampoline after the signal has been
* delivered.
*/
tcb->xcp.sigdeliver = (FAR void *)sigdeliver;
tcb->xcp.saved_pc = CURRENT_REGS[REG_PC];
tcb->xcp.saved_cpsr = CURRENT_REGS[REG_CPSR];
/* Then set up vector to the trampoline with interrupts
* disabled. The kernel-space trampoline must run in
* privileged thread mode.
*/ */
CURRENT_REGS[REG_PC] = (uint32_t)up_sigdeliver; CURRENT_REGS[REG_PC] = (uint32_t)up_sigdeliver;
CURRENT_REGS[REG_CPSR] = (PSR_MODE_SVC | PSR_I_BIT | PSR_F_BIT); CURRENT_REGS[REG_CPSR] = (PSR_MODE_SVC | PSR_I_BIT | PSR_F_BIT);
/* In an SMP configuration, the interrupt disable logic also
* involves spinlocks that are configured per the TCB irqcount
* field. This is logically equivalent to enter_critical_section().
* The matching call to leave_critical_section() will be
* performed in up_sigdeliver().
*/
spin_setbit(&g_cpu_irqset, cpu, &g_cpu_irqsetlock,
&g_cpu_irqlock);
/* And make sure that the saved context in the TCB is the same /* And make sure that the saved context in the TCB is the same
* as the interrupt return context. * as the interrupt return context.
*/ */
@@ -316,6 +304,23 @@ void up_schedule_sigaction(struct tcb_s *tcb, sig_deliver_t sigdeliver)
up_savestate(tcb->xcp.regs); up_savestate(tcb->xcp.regs);
} }
/* Increment the IRQ lock count so that when the task is restarted,
* it will hold the IRQ spinlock.
*/
DEBUGASSERT(tcb->irqcount < INT16_MAX);
tcb->irqcount++;
/* In an SMP configuration, the interrupt disable logic also
* involves spinlocks that are configured per the TCB irqcount
* field. This is logically equivalent to enter_critical_section().
* The matching call to leave_critical_section() will be
* performed in up_sigdeliver().
*/
spin_setbit(&g_cpu_irqset, cpu, &g_cpu_irqsetlock,
&g_cpu_irqlock);
/* RESUME the other CPU if it was PAUSED */ /* RESUME the other CPU if it was PAUSED */
if (cpu != me) if (cpu != me)
@@ -327,7 +332,7 @@ void up_schedule_sigaction(struct tcb_s *tcb, sig_deliver_t sigdeliver)
/* Otherwise, we are (1) signaling a task is not running from an /* Otherwise, we are (1) signaling a task is not running from an
* interrupt handler or (2) we are not in an interrupt handler and the * interrupt handler or (2) we are not in an interrupt handler and the
* running task is signalling some other non-running task. * running task is signaling some other non-running task.
*/ */
else else
sched/signal/sig_dispatch.c
+1 -1
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@@ -413,7 +413,7 @@ int nxsig_tcbdispatch(FAR struct tcb_s *stcb, siginfo_t *info)
* Description: * Description:
* This is the front-end for nxsig_tcbdispatch that should be typically * This is the front-end for nxsig_tcbdispatch that should be typically
* be used to dispatch a signal. If HAVE_GROUP_MEMBERS is defined, * be used to dispatch a signal. If HAVE_GROUP_MEMBERS is defined,
* then function will follow the group signal delivery algorthrims: * then function will follow the group signal delivery algorithms:
* *
* This front-end does the following things before calling * This front-end does the following things before calling
* nxsig_tcbdispatch. * nxsig_tcbdispatch.