From ddd40da4ccbabdd2e941837aa987e08dfa4396b4 Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Wed, 1 May 2013 17:25:43 +0200 Subject: [PATCH] x86/signals: Merge EFLAGS bit clearing into a single statement Merging EFLAGS bit clearing into a single statement, to ensure EFLAGS bits are being cleared in a single instruction. Signed-off-by: Jiri Olsa Tested-by: Oleg Nesterov Reviewed-by: Frederic Weisbecker Originally-Reported-by: Vince Weaver Cc: H. Peter Anvin Cc: Andi Kleen Cc: Oleg Nesterov Cc: Arnaldo Carvalho de Melo Cc: Ingo Molnar Cc: Paul Mackerras Cc: Corey Ashford Cc: Frederic Weisbecker Cc: Vince Weaver Cc: Stephane Eranian Cc: Linus Torvalds Cc: Andrew Morton Cc: Peter Zijlstra Cc: Thomas Gleixner Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/1367421944-19082-4-git-send-email-jolsa@redhat.com Signed-off-by: Ingo Molnar --- arch/x86/kernel/signal.c | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-) diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c index cb12fc9c0642..cf913587d4dd 100644 --- a/arch/x86/kernel/signal.c +++ b/arch/x86/kernel/signal.c @@ -662,21 +662,17 @@ handle_signal(struct ksignal *ksig, struct pt_regs *regs) if (!failed) { /* * Clear the direction flag as per the ABI for function entry. - */ - regs->flags &= ~X86_EFLAGS_DF; - /* + * * Clear RF when entering the signal handler, because * it might disable possible debug exception from the * signal handler. - */ - regs->flags &= ~X86_EFLAGS_RF; - /* + * * Clear TF when entering the signal handler, but * notify any tracer that was single-stepping it. * The tracer may want to single-step inside the * handler too. */ - regs->flags &= ~X86_EFLAGS_TF; + regs->flags &= ~(X86_EFLAGS_DF|X86_EFLAGS_RF|X86_EFLAGS_TF); } signal_setup_done(failed, ksig, test_thread_flag(TIF_SINGLESTEP)); }