From 075ca8c179a1381269b1a8d75162345af53541e5 Mon Sep 17 00:00:00 2001
From: Will Deacon <will.deacon@arm.com>
Date: Wed, 4 Jul 2012 18:16:30 +0100
Subject: [PATCH] --- yaml --- r: 311720 b: refs/heads/master c:
 3b0c06226783ffc836217eb34f7eca311b1e63f7 h: refs/heads/master v: v3

---
 [refs]                         |  2 +-
 trunk/arch/arm/kernel/signal.c | 13 +++++++++++++
 trunk/arch/arm/kernel/signal.h |  2 ++
 trunk/arch/arm/kernel/traps.c  |  2 ++
 4 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/[refs] b/[refs]
index e3a0bb4eb78e..24d6a3f83962 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 82401bf105495c593544375b4748f48fce70d9c4
+refs/heads/master: 3b0c06226783ffc836217eb34f7eca311b1e63f7
diff --git a/trunk/arch/arm/kernel/signal.c b/trunk/arch/arm/kernel/signal.c
index fd2392a17ac1..6d3bce5bd7bc 100644
--- a/trunk/arch/arm/kernel/signal.c
+++ b/trunk/arch/arm/kernel/signal.c
@@ -27,6 +27,7 @@
  */
 #define SWI_SYS_SIGRETURN	(0xef000000|(__NR_sigreturn)|(__NR_OABI_SYSCALL_BASE))
 #define SWI_SYS_RT_SIGRETURN	(0xef000000|(__NR_rt_sigreturn)|(__NR_OABI_SYSCALL_BASE))
+#define SWI_SYS_RESTART		(0xef000000|__NR_restart_syscall|__NR_OABI_SYSCALL_BASE)
 
 /*
  * With EABI, the syscall number has to be loaded into r7.
@@ -46,6 +47,18 @@ const unsigned long sigreturn_codes[7] = {
 	MOV_R7_NR_RT_SIGRETURN, SWI_SYS_RT_SIGRETURN, SWI_THUMB_RT_SIGRETURN,
 };
 
+/*
+ * Either we support OABI only, or we have EABI with the OABI
+ * compat layer enabled.  In the later case we don't know if
+ * user space is EABI or not, and if not we must not clobber r7.
+ * Always using the OABI syscall solves that issue and works for
+ * all those cases.
+ */
+const unsigned long syscall_restart_code[2] = {
+	SWI_SYS_RESTART,	/* swi	__NR_restart_syscall */
+	0xe49df004,		/* ldr	pc, [sp], #4 */
+};
+
 /*
  * atomically swap in the new signal mask, and wait for a signal.
  */
diff --git a/trunk/arch/arm/kernel/signal.h b/trunk/arch/arm/kernel/signal.h
index 5ff067b7c752..6fcfe8398aa4 100644
--- a/trunk/arch/arm/kernel/signal.h
+++ b/trunk/arch/arm/kernel/signal.h
@@ -8,5 +8,7 @@
  * published by the Free Software Foundation.
  */
 #define KERN_SIGRETURN_CODE	(CONFIG_VECTORS_BASE + 0x00000500)
+#define KERN_RESTART_CODE	(KERN_SIGRETURN_CODE + sizeof(sigreturn_codes))
 
 extern const unsigned long sigreturn_codes[7];
+extern const unsigned long syscall_restart_code[2];
diff --git a/trunk/arch/arm/kernel/traps.c b/trunk/arch/arm/kernel/traps.c
index 4928d89758f4..3647170e9a16 100644
--- a/trunk/arch/arm/kernel/traps.c
+++ b/trunk/arch/arm/kernel/traps.c
@@ -820,6 +820,8 @@ void __init early_trap_init(void *vectors_base)
 	 */
 	memcpy((void *)(vectors + KERN_SIGRETURN_CODE - CONFIG_VECTORS_BASE),
 	       sigreturn_codes, sizeof(sigreturn_codes));
+	memcpy((void *)(vectors + KERN_RESTART_CODE - CONFIG_VECTORS_BASE),
+	       syscall_restart_code, sizeof(syscall_restart_code));
 
 	flush_icache_range(vectors, vectors + PAGE_SIZE);
 	modify_domain(DOMAIN_USER, DOMAIN_CLIENT);