diff options
-rw-r--r-- | nuttx/arch/arm/src/armv7-a/arm_syscall.c | 57 |
1 files changed, 15 insertions, 42 deletions
diff --git a/nuttx/arch/arm/src/armv7-a/arm_syscall.c b/nuttx/arch/arm/src/armv7-a/arm_syscall.c index f79b0df6a..542f9c7d0 100644 --- a/nuttx/arch/arm/src/armv7-a/arm_syscall.c +++ b/nuttx/arch/arm/src/armv7-a/arm_syscall.c @@ -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 */ - -#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 - - /* Set current_regs to NULL to indicate that we are no longer in an - * interrupt handler. - */ + /* Report what happened */ - regs = (uint32_t *)current_regs; - current_regs = NULL; + svcdbg("SYSCALL Return: %d \n", regs[REG_R0]); - /* 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; |