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nuttx/arch/xtensa/src/common/xtensa_schedsigaction.c

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/****************************************************************************
* arch/xtensa/src/common/arm_schedulesigaction.c
*
* Copyright (C) 2016-2018 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <stdint.h>
#include <sched.h>
#include <debug.h>
#include <nuttx/irq.h>
#include <nuttx/arch.h>
#include "sched/sched.h"
#include "xtensa.h"
#include "irq/irq.h"
#ifndef CONFIG_DISABLE_SIGNALS
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: up_schedule_sigaction
*
* Description:
* This function is called by the OS when one or more
* signal handling actions have been queued for execution.
* The architecture specific code must configure things so
* that the 'sigdeliver' callback is executed on the thread
* specified by 'tcb' as soon as possible.
*
* This function may be called from interrupt handling logic.
*
* This operation should not cause the task to be unblocked
* nor should it cause any immediate execution of sigdeliver.
* Typically, a few cases need to be considered:
*
* (1) This function may be called from an interrupt handler
* During interrupt processing, all xcptcontext structures
* should be valid for all tasks. That structure should
* be modified to invoke sigdeliver() either on return
* from (this) interrupt or on some subsequent context
* switch to the recipient task.
* (2) If not in an interrupt handler and the tcb is NOT
* the currently executing task, then again just modify
* the saved xcptcontext structure for the recipient
* task so it will invoke sigdeliver when that task is
* later resumed.
* (3) If not in an interrupt handler and the tcb IS the
* currently executing task -- just call the signal
* handler now.
*
****************************************************************************/
#ifndef CONFIG_SMP
void up_schedule_sigaction(struct tcb_s *tcb, sig_deliver_t sigdeliver)
{
irqstate_t flags;
sinfo("tcb=0x%p sigdeliver=0x%p\n", tcb, sigdeliver);
/* Make sure that interrupts are disabled */
flags = enter_critical_section();
/* Refuse to handle nested signal actions */
if (!tcb->xcp.sigdeliver)
{
/* First, handle some special cases when the signal is being delivered
* to the currently executing task.
*/
sinfo("rtcb=0x%p CURRENT_REGS=0x%p\n", this_task(), CURRENT_REGS);
if (tcb == this_task())
{
/* CASE 1: We are not in an interrupt handler and a task is
* signaling itself for some reason.
*/
if (!CURRENT_REGS)
{
/* In this case just deliver the signal now.
* REVISIT: Signal handler will run in a critical section!
*/
sigdeliver(tcb);
}
/* CASE 2: We are in an interrupt handler AND the interrupted
* task is the same as the one that must receive the signal, then
* we will have to modify the return 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 signaling itself, but a context switch
* to another task has occurred so that CURRENT_REGS does not
* refer to the thread of this_task()!
*/
else
{
/* Save the return pc and ps. These will be restored by the
* signal trampoline after the signals have been delivered.
*
* NOTE: that hi-priority interrupts are not disabled.
*/
tcb->xcp.sigdeliver = sigdeliver;
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
* as the interrupt return context.
*/
xtensa_savestate(tcb->xcp.regs);
}
}
/* 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
* running task is signaling some non-running task.
*/
else
{
/* Save the return pc and ps. These will be restored by the
* signal trampoline after the signals have been delivered.
*
* NOTE: that hi-priority interrupts are not disabled.
*/
tcb->xcp.sigdeliver = sigdeliver;
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
*/
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
}
}
leave_critical_section(flags);
}
#endif /* !CONFIG_SMP */
#ifdef CONFIG_SMP
void up_schedule_sigaction(struct tcb_s *tcb, sig_deliver_t sigdeliver)
{
irqstate_t flags;
int cpu;
int me;
sinfo("tcb=0x%p sigdeliver=0x%p\n", tcb, sigdeliver);
/* Make sure that interrupts are disabled */
flags = enter_critical_section();
/* Refuse to handle nested signal actions */
if (!tcb->xcp.sigdeliver)
{
/* First, handle some special cases when the signal is being delivered
* to task that is currently executing on any CPU.
*/
sinfo("rtcb=0x%p CURRENT_REGS=0x%p\n", this_task(), CURRENT_REGS);
if (tcb->task_state == TSTATE_TASK_RUNNING)
{
me = this_cpu();
cpu = tcb->cpu;
/* CASE 1: We are not in an interrupt handler and a task is
* signaling itself for some reason.
*/
if (cpu == me && !CURRENT_REGS)
{
/* In this case just deliver the signal now.
* REVISIT: Signal handler will run in a critical section!
*/
sigdeliver(tcb);
}
/* CASE 2: The task that needs to receive the signal is running.
* This could happen if the task is running on another CPU OR if
* we are in an interrupt handler and the task is running on this
* 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
* state as well as the state in the TCB.
*/
else
{
/* If we signaling a task running on the other CPU, we have
* to PAUSE the other CPU.
*/
if (cpu != me)
{
/* Pause the CPU */
up_cpu_pause(cpu);
/* Wait while the pause request is pending */
while (up_cpu_pausereq(cpu))
{
}
/* Now tcb on the other CPU can be accessed safely */
/* 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.
*/
tcb->xcp.sigdeliver = sigdeliver;
tcb->xcp.saved_pc = tcb->xcp.regs[REG_PC];
tcb->xcp.saved_ps = tcb->xcp.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
}
else
{
/* tcb is running on the same CPU */
/* 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.
*/
tcb->xcp.sigdeliver = sigdeliver;
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
* as the interrupt return context.
*/
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 */
if (cpu != me)
{
up_cpu_resume(cpu);
}
}
}
/* 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
* running task is signaling some other non-running task.
*/
else
{
/* Save the return pc and ps. These will be restored by the
* signal trampoline after the signals have been delivered.
*
* NOTE: that hi-priority interrupts are not disabled.
*/
tcb->xcp.sigdeliver = sigdeliver;
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,
* it will hold the IRQ spinlock.
*/
DEBUGASSERT(tcb->irqcount < INT16_MAX);
tcb->irqcount++;
/* Then set up to vector to the trampoline with interrupts
* disabled
*/
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
}
}
leave_critical_section(flags);
}
#endif /* CONFIG_SMP */
#endif /* !CONFIG_DISABLE_SIGNALS */
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