From: Stephen Rothwell <sfr@canb.auug.org.au>
Date: Fri, 6 Jul 2012 00:32:57 +0000 (+1000)
Subject: Revert "arm: get rid of TIF_SYSCALL_RESTARTSYS"
X-Git-Tag: next-20120724~4^2~2
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=fcfc819686ce6edf70f4ddfb5e16f0f036c2797c;p=karo-tx-linux.git

Revert "arm: get rid of TIF_SYSCALL_RESTARTSYS"

This reverts commit 76c3f4da3ee47b68304dbe0f64e86562e7945bf3.

requested by Russell King.
---

diff --git a/arch/arm/include/asm/thread_info.h b/arch/arm/include/asm/thread_info.h
index b2d6b412172d..8564a6dcb0bc 100644
--- a/arch/arm/include/asm/thread_info.h
+++ b/arch/arm/include/asm/thread_info.h
@@ -148,6 +148,7 @@ extern int vfp_restore_user_hwstate(struct user_vfp __user *,
 #define TIF_NOTIFY_RESUME	2	/* callback before returning to user */
 #define TIF_SYSCALL_TRACE	8
 #define TIF_SYSCALL_AUDIT	9
+#define TIF_SYSCALL_RESTARTSYS	10
 #define TIF_USING_IWMMXT	17
 #define TIF_MEMDIE		18	/* is terminating due to OOM killer */
 #define TIF_RESTORE_SIGMASK	20
@@ -161,9 +162,11 @@ extern int vfp_restore_user_hwstate(struct user_vfp __user *,
 #define _TIF_SYSCALL_AUDIT	(1 << TIF_SYSCALL_AUDIT)
 #define _TIF_USING_IWMMXT	(1 << TIF_USING_IWMMXT)
 #define _TIF_SECCOMP		(1 << TIF_SECCOMP)
+#define _TIF_SYSCALL_RESTARTSYS	(1 << TIF_SYSCALL_RESTARTSYS)
 
 /* Checks for any syscall work in entry-common.S */
-#define _TIF_SYSCALL_WORK (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT)
+#define _TIF_SYSCALL_WORK (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \
+			   _TIF_SYSCALL_RESTARTSYS)
 
 /*
  * Change these and you break ASM code in entry-common.S
diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S
index 45046b5506eb..0e647da6a792 100644
--- a/arch/arm/kernel/entry-common.S
+++ b/arch/arm/kernel/entry-common.S
@@ -54,10 +54,10 @@ work_pending:
 	mov	r0, sp				@ 'regs'
 	mov	r2, why				@ 'syscall'
 	bl	do_work_pending
-	cmp	r0, #0
+	tst	r0, #1
 	beq	no_work_pending
-	movlt	scno, #(__NR_restart_syscall - __NR_SYSCALL_BASE)
-	ldmia	sp, {r0 - r5}			@ have to reload r0 - r5
+	mov	r0, sp				@ pointer to regs
+	ldmia	r0, {r0 - r5}			@ have to reload r0 - r5
 	b	local_restart			@ ... and off we go
 
 /*
diff --git a/arch/arm/kernel/ptrace.c b/arch/arm/kernel/ptrace.c
index fc86b76537ee..5700a7ae7f0b 100644
--- a/arch/arm/kernel/ptrace.c
+++ b/arch/arm/kernel/ptrace.c
@@ -918,6 +918,8 @@ asmlinkage int syscall_trace(int why, struct pt_regs *regs, int scno)
 		audit_syscall_entry(AUDIT_ARCH_ARM, scno, regs->ARM_r0,
 				    regs->ARM_r1, regs->ARM_r2, regs->ARM_r3);
 
+	if (why == 0 && test_and_clear_thread_flag(TIF_SYSCALL_RESTARTSYS))
+		scno = __NR_restart_syscall - __NR_SYSCALL_BASE;
 	if (!test_thread_flag(TIF_SYSCALL_TRACE))
 		return scno;
 
diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c
index 56f72d257ebd..c4368c67b042 100644
--- a/arch/arm/kernel/signal.c
+++ b/arch/arm/kernel/signal.c
@@ -590,7 +590,7 @@ static int do_signal(struct pt_regs *regs, int syscall)
 		 */
 		switch (retval) {
 		case -ERESTART_RESTARTBLOCK:
-			restart -= 2;
+			restart++;
 		case -ERESTARTNOHAND:
 		case -ERESTARTSYS:
 		case -ERESTARTNOINTR:
@@ -628,9 +628,13 @@ static int do_signal(struct pt_regs *regs, int syscall)
 		return 0;
 	}
 
-	restore_saved_sigmask();
-	if (unlikely(restart))
+	if (unlikely(restart)) {
+		if (restart > 1)
+			set_thread_flag(TIF_SYSCALL_RESTARTSYS);
 		regs->ARM_pc = continue_addr;
+	}
+
+	restore_saved_sigmask();
 	return restart;
 }
 
@@ -645,14 +649,13 @@ do_work_pending(struct pt_regs *regs, unsigned int thread_flags, int syscall)
 				return 0;
 			local_irq_enable();
 			if (thread_flags & _TIF_SIGPENDING) {
-				int restart = do_signal(regs, syscall);
-				if (unlikely(restart)) {
+				if (unlikely(do_signal(regs, syscall))) {
 					/*
 					 * Restart without handlers.
 					 * Deal with it without leaving
 					 * the kernel space.
 					 */
-					return restart;
+					return 1;
 				}
 				syscall = 0;
 			} else {