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Correct stack handling is signal deliver to user processes

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This commit is contained in:
Gregory Nutt 2014-09-16 13:33:13 -06:00
parent 0bedf06b49
commit 058229b626
1 changed files with 13 additions and 23 deletions
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36
arch/arm/src/armv7-a/arm_syscall.c
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@ -352,10 +352,6 @@ uint32_t *arm_syscall(uint32_t *regs)
case SYS_signal_handler:
{
FAR struct tcb_s *rtcb = sched_self();
#ifdef CONFIG_ARCH_KERNEL_STACK
int depth;
#endif
/* Remember the caller's return address */
DEBUGASSERT(rtcb->xcp.sigreturn == 0);
@ -384,20 +380,19 @@ uint32_t *arm_syscall(uint32_t *regs)
regs[REG_R3] = *(uint32_t*)(regs[REG_SP]+4);
#ifdef CONFIG_ARCH_KERNEL_STACK
/* If this is a nested SYSCALL and if there is an allocated kernel
* stack, then we must be operating on the kernal stack now. We
* need to switch back to the user stack before dispatching the
* signal handler to the user code.
/* If we are signalling a user process, then we must be operating
* on the kernel stack now. We need to switch back to the user
* stack before dispatching the signal handler to the user code.
* The existence of an allocated kernel stack is sufficient
* information to make this decision.
*/
depth = rtcb->xcp.nsyscalls;
if (depth > 0 && rtcb->xcp.kstack != NULL)
if (rtcb->xcp.kstack != NULL)
{
DEBUGASSERT(rtcb->xcp.kstkptr == NULL &&
rtcb->xcp.ustkptr[depth - 1] != 0);
DEBUGASSERT(rtcb->xcp.kstkptr == NULL && rtcb->xcp.ustkptr != NULL);
rtcb->xcp.kstkptr = (FAR uint32_t *)regs[REG_SP];
regs[REG_SP] = (uint32_t)rtcb->xcp.ustkptr[depth - 1];
regs[REG_SP] = (uint32_t)rtcb->xcp.ustkptr;
}
#endif
}
@ -417,9 +412,6 @@ uint32_t *arm_syscall(uint32_t *regs)
case SYS_signal_handler_return:
{
FAR struct tcb_s *rtcb = sched_self();
#ifdef CONFIG_ARCH_KERNEL_STACK
int depth;
#endif
/* Set up to return to the kernel-mode signal dispatching logic. */
@ -431,17 +423,15 @@ uint32_t *arm_syscall(uint32_t *regs)
rtcb->xcp.sigreturn = 0;
#ifdef CONFIG_ARCH_KERNEL_STACK
/* If this is a nested SYSCALL and if there is an allocated kernel
* stack, we must be using the user stack to dispatch to the signal
* handler. We need to switch to back to the kernel user stack
* before returning to the kernel mode signal trampoline.
/* We must enter here be using the user stack. We need to switch
* to back to the kernel user stack before returning to the kernel
* mode signal trampoline.
*/
depth = rtcb->xcp.nsyscalls;
if (depth > 0 && rtcb->xcp.kstack != NULL)
if (rtcb->xcp.kstack != NULL)
{
DEBUGASSERT(rtcb->xcp.kstkptr != NULL &&
(uint32_t)rtcb->xcp.ustkptr[depth - 1] == regs[REG_SP]);
(uint32_t)rtcb->xcp.ustkptr == regs[REG_SP]);
regs[REG_SP] = (uint32_t)rtcb->xcp.kstkptr;
rtcb->xcp.kstkptr = NULL;