From f606a6ff222dc7dceeb4d0e214ce4f55d9c6b0e6 Mon Sep 17 00:00:00 2001
From: Nicolas Pitre <nico@cam.org>
Date: Thu, 22 Jun 2006 22:18:45 +0100
Subject: [PATCH] [ARM] 3626/1: ARM EABI: fix syscall restarting
Patch from Nicolas Pitre
The RESTARTBLOCK case currently store some code on the stack to invoke
sys_restart_syscall. However this is ABI dependent and there is a
mismatch with the way __NR_restart_syscall gets defined when the kernel
is compiled for EABI.
There is also a long standing bug in the thumb case since with OABI the
__NR_restart_syscall value includes __NR_SYSCALL_BASE which should not
be the case for Thumb syscalls.
Credits to Yauheni Kaliuta <yauheni.kaliuta@gmail.com> for finding the
EABI bug.
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
---
arch/arm/kernel/signal.c | 21 +++++++++++++++++++--
1 file changed, 19 insertions(+), 2 deletions(-)
diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c
index a0cd0a90a10..e9fe7803336 100644
--- a/arch/arm/kernel/signal.c
+++ b/arch/arm/kernel/signal.c
@@ -665,17 +665,33 @@ static int do_signal(sigset_t *oldset, struct pt_regs *regs, int syscall)
if (syscall) {
if (regs->ARM_r0 == -ERESTART_RESTARTBLOCK) {
if (thumb_mode(regs)) {
- regs->ARM_r7 = __NR_restart_syscall;
+ regs->ARM_r7 = __NR_restart_syscall - __NR_SYSCALL_BASE;
regs->ARM_pc -= 2;
} else {
+#if defined(CONFIG_AEABI) && !defined(CONFIG_OABI_COMPAT)
+ regs->ARM_r7 = __NR_restart_syscall;
+ regs->ARM_pc -= 4;
+#else
u32 __user *usp;
+ u32 swival = __NR_restart_syscall;
regs->ARM_sp -= 12;
usp = (u32 __user *)regs->ARM_sp;
+ /*
+ * Either we supports 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.
+ */
+ swival = swival - __NR_SYSCAll_BASE + __NR_OABI_SYSCALL_BASE;
+
put_user(regs->ARM_pc, &usp[0]);
/* swi __NR_restart_syscall */
- put_user(0xef000000 | __NR_restart_syscall, &usp[1]);
+ put_user(0xef000000 | swival, &usp[1]);
/* ldr pc, [sp], #12 */
put_user(0xe49df00c, &usp[2]);
@@ -683,6 +699,7 @@ static int do_signal(sigset_t *oldset, struct pt_regs *regs, int syscall)
(unsigned long)(usp + 3));
regs->ARM_pc = regs->ARM_sp + 4;
+#endif
}
}
if (regs->ARM_r0 == -ERESTARTNOHAND ||
--
2.41.3