100 lines
2.2 KiB
C
100 lines
2.2 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);
|
||
|
|
}
|
||
|
|
|
||
|
|
static __always_inline unsigned long smap_save(void)
|
||
|
|
{
|
||
|
|
unsigned long flags;
|
||
|
|
|
||
|
|
asm volatile (ALTERNATIVE("", "pushf; pop %0; " __stringify(__ASM_CLAC),
|
||
|
|
X86_FEATURE_SMAP)
|
||
|
|
: "=rm" (flags) : : "memory", "cc");
|
||
|
|
|
||
|
|
return flags;
|
||
|
|
}
|
||
|
|
|
||
|
|
static __always_inline void smap_restore(unsigned long flags)
|
||
|
|
{
|
||
|
|
asm volatile (ALTERNATIVE("", "push %0; popf", X86_FEATURE_SMAP)
|
||
|
|
: : "g" (flags) : "memory", "cc");
|
||
|
|
}
|
||
|
|
|
||
|
|
/* 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) { }
|
||
|
|
|
||
|
|
static inline unsigned long smap_save(void) { return 0; }
|
||
|
|
static inline void smap_restore(unsigned long flags) { }
|
||
|
|
|
||
|
|
#define ASM_CLAC
|
||
|
|
#define ASM_STAC
|
||
|
|
|
||
|
|
#endif /* CONFIG_X86_SMAP */
|
||
|
|
|
||
|
|
#endif /* __ASSEMBLY__ */
|
||
|
|
|
||
|
|
#endif /* _ASM_X86_SMAP_H */
|