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Commit ddd40da4 authored by Jiri Olsa's avatar Jiri Olsa Committed by Ingo Molnar
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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: default avatarJiri Olsa <jolsa@redhat.com>
Tested-by: default avatarOleg Nesterov <oleg@redhat.com>
Reviewed-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
Originally-Reported-by: default avatarVince Weaver <vincent.weaver@maine.edu>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: Stephane Eranian <eranian@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1367421944-19082-4-git-send-email-jolsa@redhat.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 24cda109

arch/x86/kernel/signal.c

+3 −7
Original line number Diff line number Diff line
@@ -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));

}