From 10469350e345599dfef3fa78a7c19fb230e674c1 Mon Sep 17 00:00:00 2001 From: Christian Ruppert Date: Wed, 2 Oct 2013 11:13:38 +0200 Subject: [PATCH] ARC: Fix signal frame management for SA_SIGINFO Previously, when a signal was registered with SA_SIGINFO, parameters 2 and 3 of the signal handler were written to registers r1 and r2 before the register set was saved. This led to corruption of these two registers after returning from the signal handler (the wrong values were restored). With this patch, registers are now saved before any parameters are passed, thus maintaining the processor state from before signal entry. Signed-off-by: Christian Ruppert Signed-off-by: Vineet Gupta --- arch/arc/kernel/signal.c | 25 +++++++++++++------------ 1 file changed, 13 insertions(+), 12 deletions(-) diff --git a/arch/arc/kernel/signal.c b/arch/arc/kernel/signal.c index ee6ef2f60a28..7e95e1a86510 100644 --- a/arch/arc/kernel/signal.c +++ b/arch/arc/kernel/signal.c @@ -101,7 +101,6 @@ SYSCALL_DEFINE0(rt_sigreturn) { struct rt_sigframe __user *sf; unsigned int magic; - int err; struct pt_regs *regs = current_pt_regs(); /* Always make any pending restarted system calls return -EINTR */ @@ -119,15 +118,16 @@ SYSCALL_DEFINE0(rt_sigreturn) if (!access_ok(VERIFY_READ, sf, sizeof(*sf))) goto badframe; - err = restore_usr_regs(regs, sf); - err |= __get_user(magic, &sf->sigret_magic); - if (err) + if (__get_user(magic, &sf->sigret_magic)) goto badframe; if (unlikely(is_do_ss_needed(magic))) if (restore_altstack(&sf->uc.uc_stack)) goto badframe; + if (restore_usr_regs(regs, sf)) + goto badframe; + /* Don't restart from sigreturn */ syscall_wont_restart(regs); @@ -190,6 +190,15 @@ setup_rt_frame(int signo, struct k_sigaction *ka, siginfo_t *info, if (!sf) return 1; + /* + * w/o SA_SIGINFO, struct ucontext is partially populated (only + * uc_mcontext/uc_sigmask) for kernel's normal user state preservation + * during signal handler execution. This works for SA_SIGINFO as well + * although the semantics are now overloaded (the same reg state can be + * inspected by userland: but are they allowed to fiddle with it ? + */ + err |= stash_usr_regs(sf, regs, set); + /* * SA_SIGINFO requires 3 args to signal handler: * #1: sig-no (common to any handler) @@ -213,14 +222,6 @@ setup_rt_frame(int signo, struct k_sigaction *ka, siginfo_t *info, magic = MAGIC_SIGALTSTK; } - /* - * w/o SA_SIGINFO, struct ucontext is partially populated (only - * uc_mcontext/uc_sigmask) for kernel's normal user state preservation - * during signal handler execution. This works for SA_SIGINFO as well - * although the semantics are now overloaded (the same reg state can be - * inspected by userland: but are they allowed to fiddle with it ? - */ - err |= stash_usr_regs(sf, regs, set); err |= __put_user(magic, &sf->sigret_magic); if (err) return err;