From f606a6ff222dc7dceeb4d0e214ce4f55d9c6b0e6 Mon Sep 17 00:00:00 2001 From: Nicolas Pitre 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 for finding the EABI bug. Signed-off-by: Nicolas Pitre Signed-off-by: Russell King --- 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 a0cd0a90a10d..e9fe78033361 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 || -- 2.20.1