commit cc7571b226c93b032164ebb3ff3b365651c4652f
Author: Aurelien Jarno <[EMAIL PROTECTED]>
Date:   Sat Mar 8 11:43:52 2008 +0100

    x86: Clear DF before calling signal handler
    
    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.
    This become 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.
    
    This is a backport of patch e40cd10ccff3d9fbffd57b93780bee4b7b9bff51
    ("x86: clear DF before calling signal handler") that has been applied
    in 2.6.25-rc.
    
    Signed-off-by: Aurelien Jarno <[EMAIL PROTECTED]>
    Signed-off-by: Chris Wright <[EMAIL PROTECTED]>
    Signed-off-by: Greg Kroah-Hartman <[EMAIL PROTECTED]>

diff --git a/arch/x86/ia32/ia32_signal.c b/arch/x86/ia32/ia32_signal.c
index 6ea19c2..4eaaf78 100644
--- a/arch/x86/ia32/ia32_signal.c
+++ b/arch/x86/ia32/ia32_signal.c
@@ -494,7 +494,7 @@ int ia32_setup_frame(int sig, struct k_sigaction *ka,
        regs->ss = __USER32_DS; 
 
        set_fs(USER_DS);
-       regs->eflags &= ~TF_MASK;
+       regs->eflags &= ~(TF_MASK | 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->eflags &= ~TF_MASK;
+       regs->eflags &= ~(TF_MASK | 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 9bdd830..20056db 100644
--- a/arch/x86/kernel/signal_32.c
+++ b/arch/x86/kernel/signal_32.c
@@ -396,7 +396,7 @@ static int setup_frame(int sig, struct k_sigaction *ka,
         * The tracer may want to single-step inside the
         * handler too.
         */
-       regs->eflags &= ~TF_MASK;
+       regs->eflags &= ~(TF_MASK | X86_EFLAGS_DF);
        if (test_thread_flag(TIF_SINGLESTEP))
                ptrace_notify(SIGTRAP);
 
@@ -489,7 +489,7 @@ 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->eflags &= ~TF_MASK;
+       regs->eflags &= ~(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 ab086b0..62964c5 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->eflags &= ~TF_MASK;
+       regs->eflags &= ~(TF_MASK | X86_EFLAGS_DF);
        if (test_thread_flag(TIF_SINGLESTEP))
                ptrace_notify(SIGTRAP);
 #ifdef DEBUG_SIG
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