sh: Fix up spurious syscall restarting.

The T-bit manipulation for syscall error checking had the side effect of
spuriously returning ERESTART* errno values over EINTR. So, we simplify
the error checking a bit and leave the T-bit alone.
Reported-by: Kaz Kojima <kkojima@rr.iij4u.or.jp>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

arch/sh/include/asm/syscall_32.h

@@ -21,23 +21,10 @@ static inline void syscall_rollback(struct task_struct *task,
 	 */
 }
 
-static inline bool syscall_has_error(struct pt_regs *regs)
-{
-	return (regs->sr & 0x1) ? true : false;
-}
-static inline void syscall_set_error(struct pt_regs *regs)
-{
-	regs->sr |= 0x1;
-}
-static inline void syscall_clear_error(struct pt_regs *regs)
-{
-	regs->sr &= ~0x1;
-}
-
 static inline long syscall_get_error(struct task_struct *task,
 				     struct pt_regs *regs)
 {
-	return syscall_has_error(regs) ? regs->regs[0] : 0;
+	return IS_ERR_VALUE(regs->regs[0]) ? regs->regs[0] : 0;
 }
 
 static inline long syscall_get_return_value(struct task_struct *task,
@@ -50,13 +37,10 @@ static inline void syscall_set_return_value(struct task_struct *task,
 					    struct pt_regs *regs,
 					    int error, long val)
 {
-	if (error) {
-		syscall_set_error(regs);
+	if (error)
 		regs->regs[0] = -error;
-	} else {
-		syscall_clear_error(regs);
+	else
 		regs->regs[0] = val;
-	}
 }
 
 static inline void syscall_get_arguments(struct task_struct *task,

arch/sh/include/asm/syscall_64.h

@@ -21,23 +21,10 @@ static inline void syscall_rollback(struct task_struct *task,
 	 */
 }
 
-static inline bool syscall_has_error(struct pt_regs *regs)
-{
-	return (regs->sr & 0x1) ? true : false;
-}
-static inline void syscall_set_error(struct pt_regs *regs)
-{
-	regs->sr |= 0x1;
-}
-static inline void syscall_clear_error(struct pt_regs *regs)
-{
-	regs->sr &= ~0x1;
-}
-
 static inline long syscall_get_error(struct task_struct *task,
 				     struct pt_regs *regs)
 {
-	return syscall_has_error(regs) ? regs->regs[9] : 0;
+	return IS_ERR_VALUE(regs->regs[9]) ? regs->regs[9] : 0;
 }
 
 static inline long syscall_get_return_value(struct task_struct *task,
@@ -50,13 +37,10 @@ static inline void syscall_set_return_value(struct task_struct *task,
 					    struct pt_regs *regs,
 					    int error, long val)
 {
-	if (error) {
-		syscall_set_error(regs);
+	if (error)
 		regs->regs[9] = -error;
-	} else {
-		syscall_clear_error(regs);
+	else
 		regs->regs[9] = val;
-	}
 }
 
 static inline void syscall_get_arguments(struct task_struct *task,

arch/sh/kernel/signal_32.c

@@ -510,7 +510,6 @@ handle_syscall_restart(unsigned long save_r0, struct pt_regs *regs,
 		case -ERESTARTNOHAND:
 		no_system_call_restart:
 			regs->regs[0] = -EINTR;
-			regs->sr |= 1;
 			break;
 
 		case -ERESTARTSYS:
@@ -589,8 +588,7 @@ static void do_signal(struct pt_regs *regs, unsigned int save_r0)
 
 	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 	if (signr > 0) {
-		if (regs->sr & 1)
-			handle_syscall_restart(save_r0, regs, &ka.sa);
+		handle_syscall_restart(save_r0, regs, &ka.sa);
 
 		/* Whee!  Actually deliver the signal.  */
 		if (handle_signal(signr, &ka, &info, oldset,

arch/sh/kernel/signal_64.c

@@ -60,7 +60,6 @@ handle_syscall_restart(struct pt_regs *regs, struct sigaction *sa)
 		case -ERESTARTNOHAND:
 		no_system_call_restart:
 			regs->regs[REG_RET] = -EINTR;
-			regs->sr |= 1;
 			break;
 
 		case -ERESTARTSYS:
@@ -109,8 +108,7 @@ static int do_signal(struct pt_regs *regs, sigset_t *oldset)
 
 	signr = get_signal_to_deliver(&info, &ka, regs, 0);
 	if (signr > 0) {
-		if (regs->sr & 1)
-			handle_syscall_restart(regs, &ka.sa);
+		handle_syscall_restart(regs, &ka.sa);
 
 		/* Whee!  Actually deliver the signal.  */
 		if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {