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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@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/ce383fa9e129286ce6da6e00b53acd4c9fb5d06a.1444091585.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Andy Lutomirski 2015-10-05 17:48:21 -07:00 committed by Ingo Molnar
parent c68ca6787b
commit 4aabd140f9
1 changed files with 4 additions and 2 deletions
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6
arch/x86/entry/common.c
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@ -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