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| author | Aurelien Jarno <aurelien@aurel32.net> | 2008-03-05 19:14:24 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-03-07 16:39:14 +0100 |
| commit | e40cd10ccff3d9fbffd57b93780bee4b7b9bff51 (patch) | |
| tree | bdc58b9f84e7e4bd37da3bfb1f9a445a1560c0c3 /arch | |
| parent | ce4796d1e16cf3761dc2a02b8d588667d05b3078 (diff) | |
| download | linux-e40cd10ccff3d9fbffd57b93780bee4b7b9bff51.tar.gz linux-e40cd10ccff3d9fbffd57b93780bee4b7b9bff51.tar.bz2 linux-e40cd10ccff3d9fbffd57b93780bee4b7b9bff51.zip | |
x86: clear DF before calling signal handler
The Linux kernel currently does not clear the direction flag before
calling a signal handler, whereas the x86/x86-64 ABI requires that.
Linux had this behavior/bug forever, but this becomes a real problem
with gcc version 4.3, which assumes that the direction flag is
correctly cleared at the entry of a function.
This patches changes the setup_frame() functions to clear the
direction before entering the signal handler.
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/ia32/ia32_signal.c | 4 | ||||
| -rw-r--r-- | arch/x86/kernel/signal_32.c | 4 | ||||
| -rw-r--r-- | arch/x86/kernel/signal_64.c | 2 |
3 files changed, 5 insertions, 5 deletions
diff --git a/arch/x86/ia32/ia32_signal.c b/arch/x86/ia32/ia32_signal.c index 1c0503bdfb1a..5e7771a3ba2f 100644 --- a/arch/x86/ia32/ia32_signal.c +++ b/arch/x86/ia32/ia32_signal.c @@ -500,7 +500,7 @@ int ia32_setup_frame(int sig, struct k_sigaction *ka, regs->ss = __USER32_DS; set_fs(USER_DS); - regs->flags &= ~X86_EFLAGS_TF; + regs->flags &= ~(X86_EFLAGS_TF | X86_EFLAGS_DF); if (test_thread_flag(TIF_SINGLESTEP)) ptrace_notify(SIGTRAP); @@ -600,7 +600,7 @@ int ia32_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, regs->ss = __USER32_DS; set_fs(USER_DS); - regs->flags &= ~X86_EFLAGS_TF; + regs->flags &= ~(X86_EFLAGS_TF | X86_EFLAGS_DF); if (test_thread_flag(TIF_SINGLESTEP)) ptrace_notify(SIGTRAP); diff --git a/arch/x86/kernel/signal_32.c b/arch/x86/kernel/signal_32.c index caee1f002fed..0157a6f0f41f 100644 --- a/arch/x86/kernel/signal_32.c +++ b/arch/x86/kernel/signal_32.c @@ -407,7 +407,7 @@ static int setup_frame(int sig, struct k_sigaction *ka, * The tracer may want to single-step inside the * handler too. */ - regs->flags &= ~TF_MASK; + regs->flags &= ~(TF_MASK | X86_EFLAGS_DF); if (test_thread_flag(TIF_SINGLESTEP)) ptrace_notify(SIGTRAP); @@ -500,7 +500,7 @@ static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, * The tracer may want to single-step inside the * handler too. */ - regs->flags &= ~TF_MASK; + regs->flags &= ~(TF_MASK | X86_EFLAGS_DF); if (test_thread_flag(TIF_SINGLESTEP)) ptrace_notify(SIGTRAP); diff --git a/arch/x86/kernel/signal_64.c b/arch/x86/kernel/signal_64.c index 7347bb14e306..56b72fb67f9b 100644 --- a/arch/x86/kernel/signal_64.c +++ b/arch/x86/kernel/signal_64.c @@ -295,7 +295,7 @@ static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, see include/asm-x86_64/uaccess.h for details. */ set_fs(USER_DS); - regs->flags &= ~X86_EFLAGS_TF; + regs->flags &= ~(X86_EFLAGS_TF | X86_EFLAGS_DF); if (test_thread_flag(TIF_SINGLESTEP)) ptrace_notify(SIGTRAP); #ifdef DEBUG_SIG |