linux-stable/arch/x86/include/asm/smap.h
Borislav Petkov cd4d09ec6f x86/cpufeature: Carve out X86_FEATURE_*
Move them to a separate header and have the following
dependency:

  x86/cpufeatures.h <- x86/processor.h <- x86/cpufeature.h

This makes it easier to use the header in asm code and not
include the whole cpufeature.h and add guards for asm.

Suggested-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
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: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1453842730-28463-5-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-01-30 11:22:17 +01:00

79 lines
1.7 KiB
C

/*
* Supervisor Mode Access Prevention support
*
* Copyright (C) 2012 Intel Corporation
* Author: H. Peter Anvin <hpa@linux.intel.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; version 2
* of the License.
*/
#ifndef _ASM_X86_SMAP_H
#define _ASM_X86_SMAP_H
#include <linux/stringify.h>
#include <asm/nops.h>
#include <asm/cpufeatures.h>
/* "Raw" instruction opcodes */
#define __ASM_CLAC .byte 0x0f,0x01,0xca
#define __ASM_STAC .byte 0x0f,0x01,0xcb
#ifdef __ASSEMBLY__
#include <asm/alternative-asm.h>
#ifdef CONFIG_X86_SMAP
#define ASM_CLAC \
ALTERNATIVE "", __stringify(__ASM_CLAC), X86_FEATURE_SMAP
#define ASM_STAC \
ALTERNATIVE "", __stringify(__ASM_STAC), X86_FEATURE_SMAP
#else /* CONFIG_X86_SMAP */
#define ASM_CLAC
#define ASM_STAC
#endif /* CONFIG_X86_SMAP */
#else /* __ASSEMBLY__ */
#include <asm/alternative.h>
#ifdef CONFIG_X86_SMAP
static __always_inline void clac(void)
{
/* Note: a barrier is implicit in alternative() */
alternative("", __stringify(__ASM_CLAC), X86_FEATURE_SMAP);
}
static __always_inline void stac(void)
{
/* Note: a barrier is implicit in alternative() */
alternative("", __stringify(__ASM_STAC), X86_FEATURE_SMAP);
}
/* These macros can be used in asm() statements */
#define ASM_CLAC \
ALTERNATIVE("", __stringify(__ASM_CLAC), X86_FEATURE_SMAP)
#define ASM_STAC \
ALTERNATIVE("", __stringify(__ASM_STAC), X86_FEATURE_SMAP)
#else /* CONFIG_X86_SMAP */
static inline void clac(void) { }
static inline void stac(void) { }
#define ASM_CLAC
#define ASM_STAC
#endif /* CONFIG_X86_SMAP */
#endif /* __ASSEMBLY__ */
#endif /* _ASM_X86_SMAP_H */