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Fix hard coded values in dispatch_sysall inline assembly. Back out/corect part of last change; that was going the wrong direction.

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This commit is contained in:
Gregory Nutt 2014-08-29 10:10:47 -06:00
parent 48c2c9ed08
commit 67721c50f1
1 changed files with 15 additions and 42 deletions
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57
arch/arm/src/armv7-a/arm_syscall.c
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@ -76,6 +76,9 @@
****************************************************************************/
/****************************************************************************
* Name: dispatch_syscall
*
* Description:
* Call the stub function corresponding to the system call. NOTE the non-
* standard parameter passing:
*
@ -90,6 +93,8 @@
* The values of R4-R5 may be preserved in the proxy called by the user
* code if they are used (but otherwise will not be).
*
* WARNING: There are hard-coded values in this logic!
*
* Register usage:
*
* R0 - Need not be preserved.
@ -122,8 +127,8 @@ static void dispatch_syscall(void)
" ldr lr, [sp, #12]\n" /* Restore lr */
" add sp, sp, #16\n" /* Destroy the stack frame */
" mov r2, r0\n" /* R2=Save return value in R2 */
" mov r0, #3\n" /* R0=SYS_syscall_return */
" svc 0" /* Return from the SYSCALL */
" mov r0, #0\n" /* R0=SYS_syscall_return */
" svc #0x900001" /* Return from the SYSCALL */
);
}
#endif
@ -158,13 +163,7 @@ uint32_t *arm_syscall(uint32_t *regs)
/* Nested interrupts are not supported */
DEBUGASSERT(regs && current_regs == NULL);
/* Current regs non-zero indicates that we are processing an interrupt;
* current_regs is also used to manage interrupt level context switches.
*/
current_regs = regs;
DEBUGASSERT(regs);
/* The SYSCALL command is in R0 on entry. Parameters follow in R1..R7 */
@ -311,7 +310,7 @@ uint32_t *arm_syscall(uint32_t *regs)
#if defined(CONFIG_NUTTX_KERNEL) && !defined(CONFIG_DISABLE_SIGNALS)
case SYS_signal_handler:
{
struct tcb_s *rtcb = sched_self();
struct tcb_s *rtcb = sched_self();
/* Remember the caller's return address */
@ -355,7 +354,7 @@ uint32_t *arm_syscall(uint32_t *regs)
#if defined(CONFIG_NUTTX_KERNEL) && !defined(CONFIG_DISABLE_SIGNALS)
case SYS_signal_handler_return:
{
struct tcb_s *rtcb = sched_self();
struct tcb_s *rtcb = sched_self();
/* Set up to return to the kernel-mode signal dispatching logic. */
@ -413,39 +412,13 @@ uint32_t *arm_syscall(uint32_t *regs)
break;
}
/* Report what happened. That might difficult in the case of a context switch */
/* Report what happened */
#if defined(CONFIG_DEBUG_SYSCALL)
if (regs != current_regs)
{
svcdbg("SYSCALL Return: current_regs: %p\n", current_regs);
svcdbg(" R0: %08x %08x %08x %08x %08x %08x %08x %08x\n",
current_regs[REG_R0], current_regs[REG_R1],
current_regs[REG_R2], current_regs[REG_R3],
current_regs[REG_R4], current_regs[REG_R5],
current_regs[REG_R6], current_regs[REG_R7]);
svcdbg(" R8: %08x %08x %08x %08x %08x %08x %08x %08x\n",
current_regs[REG_R8], current_regs[REG_R9],
current_regs[REG_R10], current_regs[REG_R11],
current_regs[REG_R12], current_regs[REG_R13],
current_regs[REG_R14], current_regs[REG_R15]);
svcdbg("CPSR: %08x\n", current_regs[REG_CPSR]);
}
else
{
svcdbg("SYSCALL Return: %d\n", regs[REG_R0]);
}
#endif
svcdbg("SYSCALL Return: %d \n", regs[REG_R0]);
/* Set current_regs to NULL to indicate that we are no longer in an
* interrupt handler.
*/
regs = (uint32_t *)current_regs;
current_regs = NULL;
/* Return the last value of curent_regs. This will determine if any
* context switch will be performed on the return from the exception.
/* Return the last value of curent_regs. This supports context switchs
* on return from the exception. That capability is not used here,
* however.
*/
return regs;