[PATCH v2 30/36] x86/entry: Make irqs_disabled checks in exit code depend on lockdep

From: Andy Lutomirski
Date: Mon Oct 05 2015 - 20:51:43 EST


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

Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxx>
---
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 7d740e16038e..1d95f8835322 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();

/*
--
2.4.3

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