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Commit dd636071 authored by Andy Lutomirski's avatar Andy Lutomirski Committed by Ingo Molnar
Browse files

x86/entry: Use pt_regs_to_thread_info() in syscall entry tracing 



It generates simpler and faster code than current_thread_info().

Signed-off-by: default avatarAndy 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/a3b6633e7dcb9f673c1b619afae602d29d27d2cf.1444091585.git.luto@kernel.org


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 4aabd140

arch/x86/entry/common.c

+11 −11
Original line number Diff line number Diff line
@@ -30,6 +30,13 @@ 
#define CREATE_TRACE_POINTS

#include <trace/events/syscalls.h>



static struct thread_info *pt_regs_to_thread_info(struct pt_regs *regs)

{

	unsigned long top_of_stack =

		(unsigned long)(regs + 1) + TOP_OF_KERNEL_STACK_PADDING;

	return (struct thread_info *)(top_of_stack - THREAD_SIZE);

}



#ifdef CONFIG_CONTEXT_TRACKING

/* Called on entry from user mode with IRQs off. */

__visible void enter_from_user_mode(void)
@@ -68,14 +75,14 @@ static void do_audit_syscall_entry(struct pt_regs *regs, u32 arch) 
 */

unsigned long syscall_trace_enter_phase1(struct pt_regs *regs, u32 arch)

{

	struct thread_info *ti = pt_regs_to_thread_info(regs);

	unsigned long ret = 0;

	u32 work;



	if (IS_ENABLED(CONFIG_DEBUG_ENTRY))

		BUG_ON(regs != task_pt_regs(current));



	work = ACCESS_ONCE(current_thread_info()->flags) &

		_TIF_WORK_SYSCALL_ENTRY;

	work = ACCESS_ONCE(ti->flags) & _TIF_WORK_SYSCALL_ENTRY;



#ifdef CONFIG_CONTEXT_TRACKING

	/*
@@ -157,9 +164,9 @@ unsigned long syscall_trace_enter_phase1(struct pt_regs *regs, u32 arch) 
long syscall_trace_enter_phase2(struct pt_regs *regs, u32 arch,

				unsigned long phase1_result)

{

	struct thread_info *ti = pt_regs_to_thread_info(regs);

	long ret = 0;

	u32 work = ACCESS_ONCE(current_thread_info()->flags) &

		_TIF_WORK_SYSCALL_ENTRY;

	u32 work = ACCESS_ONCE(ti->flags) & _TIF_WORK_SYSCALL_ENTRY;



	if (IS_ENABLED(CONFIG_DEBUG_ENTRY))

		BUG_ON(regs != task_pt_regs(current));
@@ -211,13 +218,6 @@ long syscall_trace_enter(struct pt_regs *regs) 
		return syscall_trace_enter_phase2(regs, arch, phase1_result);

}



static struct thread_info *pt_regs_to_thread_info(struct pt_regs *regs)

{

	unsigned long top_of_stack =

		(unsigned long)(regs + 1) + TOP_OF_KERNEL_STACK_PADDING;

	return (struct thread_info *)(top_of_stack - THREAD_SIZE);

}



/* Called with IRQs disabled. */

__visible void prepare_exit_to_usermode(struct pt_regs *regs)

{