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arch/xtensa/common: Port the SMP change by Masayuki Ishikawa to the Xtensa family.

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This commit is contained in:
Gregory Nutt
2018-02-14 08:58:22 -06:00
parent 3ddea73dc1
commit c260ef5d59
1 changed files with 61 additions and 52 deletions
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arch/xtensa/src/common/xtensa_schedsigaction.c
+61 -52
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@@ -1,7 +1,7 @@
/**************************************************************************** /****************************************************************************
* arch/xtensa/src/common/arm_schedulesigaction.c * arch/xtensa/src/common/arm_schedulesigaction.c
* *
* Copyright (C) 2016-2017 Gregory Nutt. All rights reserved. * Copyright (C) 2016-2018 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
@@ -114,7 +114,7 @@ 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)
@@ -131,7 +131,7 @@ 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()!
*/ */
@@ -169,7 +169,7 @@ 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 non-running task. * running task is signaling some non-running task.
*/ */
else else
@@ -230,7 +230,7 @@ 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)
@@ -246,61 +246,38 @@ 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 pc and ps. These will be restored by the /* Wait while the pause request is pending */
* signal trampoline after the signals have been delivered.
*
* NOTE: that hi-priority interrupts are not disabled.
*/
tcb->xcp.sigdeliver = sigdeliver; while (up_cpu_pausereq(cpu))
tcb->xcp.saved_pc = CURRENT_REGS[REG_PC]; {
tcb->xcp.saved_ps = CURRENT_REGS[REG_PS]; }
/* 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.
*
* NOTE: that hi-priority interrupts are not disabled.
*/
/* 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_ps = tcb->xcp.regs[REG_PS];
* 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)
{
tcb->xcp.regs[REG_PC] = (uint32_t)_xtensa_sig_trampoline;
#ifdef __XTENSA_CALL0_ABI__
tcb->xcp.regs[REG_PS] = (uint32_t)(PS_INTLEVEL(XCHAL_EXCM_LEVEL) | PS_UM);
#else
tcb->xcp.regs[REG_PS] = (uint32_t)(PS_INTLEVEL(XCHAL_EXCM_LEVEL) | PS_UM | PS_WOE);
#endif
}
else
{
/* Then set up to vector to the trampoline with interrupts /* Then set up to vector to the trampoline with interrupts
* disabled * disabled
*/ */
@@ -311,16 +288,31 @@ void up_schedule_sigaction(struct tcb_s *tcb, sig_deliver_t sigdeliver)
#else #else
CURRENT_REGS[REG_PS] = (uint32_t)(PS_INTLEVEL(XCHAL_EXCM_LEVEL) | PS_UM | PS_WOE); CURRENT_REGS[REG_PS] = (uint32_t)(PS_INTLEVEL(XCHAL_EXCM_LEVEL) | PS_UM | PS_WOE);
#endif #endif
/* In an SMP configuration, the interrupt disable logic also }
* involves spinlocks that are configured per the TCB irqcount else
* field. This is logically equivalent to enter_critical_section(). {
* The matching call to leave_critical_section() will be /* tcb is running on the same CPU */
* performed in up_sigdeliver().
/* Copy tcb->xcp.regs to tcp.xcp.saved. These will be restored
* by the signal trampoline after the signal has been delivered.
*
* NOTE: that hi-priority interrupts are not disabled.
*/ */
spin_setbit(&g_cpu_irqset, cpu, &g_cpu_irqsetlock, tcb->xcp.sigdeliver = sigdeliver;
&g_cpu_irqlock); tcb->xcp.saved_pc = CURRENT_REGS[REG_PC];
tcb->xcp.saved_ps = CURRENT_REGS[REG_PS];
/* Then set up to vector to the trampoline with interrupts
* disabled
*/
CURRENT_REGS[REG_PC] = (uint32_t)_xtensa_sig_trampoline;
#ifdef __XTENSA_CALL0_ABI__
CURRENT_REGS[REG_PS] = (uint32_t)(PS_INTLEVEL(XCHAL_EXCM_LEVEL) | PS_UM);
#else
CURRENT_REGS[REG_PS] = (uint32_t)(PS_INTLEVEL(XCHAL_EXCM_LEVEL) | PS_UM | PS_WOE);
#endif
/* 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.
*/ */
@@ -328,6 +320,23 @@ void up_schedule_sigaction(struct tcb_s *tcb, sig_deliver_t sigdeliver)
xtensa_savestate(tcb->xcp.regs); xtensa_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)
@@ -339,7 +348,7 @@ 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