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[ARM] 3626/1: ARM EABI: fix syscall restarting

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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>
This commit is contained in:
Nicolas Pitre 2006-06-22 22:18:45 +01:00 committed by Russell King
parent 92b7eb8ffc
commit f606a6ff22
1 changed files with 19 additions and 2 deletions
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21
arch/arm/kernel/signal.c
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@ -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 ||