From 460d12453e1afe20416ce9536cfecb31d17a9abd Mon Sep 17 00:00:00 2001 From: Andy Lutomirski Date: Mon, 5 Oct 2015 17:48:18 -0700 Subject: [PATCH] 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 Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/r/eccff2a154ae6fb50f40228901003a6e9c24f3d0.1444091585.git.luto@kernel.org Signed-off-by: Ingo Molnar --- arch/x86/entry/common.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c index 0d1c842ef3ca..03aacd188458 100644 --- a/arch/x86/entry/common.c +++ b/arch/x86/entry/common.c @@ -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(); /* -- 2.11.4.GIT