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Message-Id: <ce383fa9e129286ce6da6e00b53acd4c9fb5d06a.1444091585.git.luto@kernel.org>
Date: Mon, 5 Oct 2015 17:48:21 -0700
From: Andy Lutomirski <luto@...nel.org>
To: x86@...nel.org, linux-kernel@...r.kernel.org
Cc: Brian Gerst <brgerst@...il.com>,
Denys Vlasenko <dvlasenk@...hat.com>,
Linus Torvalds <torvalds@...ux-foundation.org>,
Borislav Petkov <bp@...en8.de>,
Andy Lutomirski <luto@...nel.org>
Subject: [PATCH v2 33/36] x86/entry: Hide two syscall entry assertions behind CONFIG_DEBUG_ENTRY
This shaves a few cycles off the slow paths.
Signed-off-by: Andy Lutomirski <luto@...nel.org>
---
arch/x86/entry/common.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c
index 3ae6191ad1a2..88966fbf7125 100644
--- a/arch/x86/entry/common.c
+++ b/arch/x86/entry/common.c
@@ -71,7 +71,8 @@ unsigned long syscall_trace_enter_phase1(struct pt_regs *regs, u32 arch)
unsigned long ret = 0;
u32 work;
- BUG_ON(regs != task_pt_regs(current));
+ if (IS_ENABLED(CONFIG_DEBUG_ENTRY))
+ BUG_ON(regs != task_pt_regs(current));
work = ACCESS_ONCE(current_thread_info()->flags) &
_TIF_WORK_SYSCALL_ENTRY;
@@ -160,7 +161,8 @@ long syscall_trace_enter_phase2(struct pt_regs *regs, u32 arch,
u32 work = ACCESS_ONCE(current_thread_info()->flags) &
_TIF_WORK_SYSCALL_ENTRY;
- BUG_ON(regs != task_pt_regs(current));
+ if (IS_ENABLED(CONFIG_DEBUG_ENTRY))
+ BUG_ON(regs != task_pt_regs(current));
/*
* If we stepped into a sysenter/syscall insn, it trapped in
--
2.4.3
--
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