Commit 460d1245 authored Oct 05, 2015 by Andy Lutomirski Committed by Ingo Molnar Oct 09, 2015

x86/entry: Make irqs_disabled checks in exit code depend on lockdep

These checks are quite slow.  Disable them in non-lockdep
kernels to reduce the performance hit.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/eccff2a154ae6fb50f40228901003a6e9c24f3d0.1444091585.git.luto@kernel.org

Signed-off-by: Ingo Molnar <mingo@kernel.org>

parent 8b13c255

arch/x86/entry/common.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -219,7 +219,7 @@ static struct thread_info pt_regs_to_thread_info(struct pt_regs regs)
		/* Called with IRQs disabled. */
		__visible void prepare_exit_to_usermode(struct pt_regs *regs)
		{
		if (WARN_ON(!irqs_disabled()))
		if (IS_ENABLED(CONFIG_PROVE_LOCKING) && WARN_ON(!irqs_disabled()))
		local_irq_disable();

		lockdep_sys_exit();
		@@ -281,8 +281,8 @@ __visible void syscall_return_slowpath(struct pt_regs *regs)

		CT_WARN_ON(ct_state() != CONTEXT_KERNEL);

		if (WARN(irqs_disabled(), "syscall %ld left IRQs disabled",
		regs->orig_ax))
		if (IS_ENABLED(CONFIG_PROVE_LOCKING) &&
		WARN(irqs_disabled(), "syscall %ld left IRQs disabled", regs->orig_ax))
		local_irq_enable();

		/*