Contributors: 5
| Author |
Tokens |
Token Proportion |
Commits |
Commit Proportion |
| H. Peter Anvin |
86 |
65.65% |
2 |
22.22% |
| Peter Zijlstra |
36 |
27.48% |
3 |
33.33% |
| Al Viro |
4 |
3.05% |
1 |
11.11% |
| Borislav Petkov |
3 |
2.29% |
2 |
22.22% |
| Thomas Gleixner |
2 |
1.53% |
1 |
11.11% |
| Total |
131 |
|
9 |
|
/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Supervisor Mode Access Prevention support
*
* Copyright (C) 2012 Intel Corporation
* Author: H. Peter Anvin <hpa@linux.intel.com>
*/
#ifndef _ASM_X86_SMAP_H
#define _ASM_X86_SMAP_H
#include <asm/nops.h>
#include <asm/cpufeatures.h>
#include <asm/alternative.h>
/* "Raw" instruction opcodes */
#define __ASM_CLAC ".byte 0x0f,0x01,0xca"
#define __ASM_STAC ".byte 0x0f,0x01,0xcb"
#ifdef __ASSEMBLY__
#define ASM_CLAC \
ALTERNATIVE "", __ASM_CLAC, X86_FEATURE_SMAP
#define ASM_STAC \
ALTERNATIVE "", __ASM_STAC, X86_FEATURE_SMAP
#else /* __ASSEMBLY__ */
static __always_inline void clac(void)
{
/* Note: a barrier is implicit in alternative() */
alternative("", __ASM_CLAC, X86_FEATURE_SMAP);
}
static __always_inline void stac(void)
{
/* Note: a barrier is implicit in alternative() */
alternative("", __ASM_STAC, X86_FEATURE_SMAP);
}
static __always_inline unsigned long smap_save(void)
{
unsigned long flags;
asm volatile ("# smap_save\n\t"
ALTERNATIVE("", "pushf; pop %0; " __ASM_CLAC "\n\t",
X86_FEATURE_SMAP)
: "=rm" (flags) : : "memory", "cc");
return flags;
}
static __always_inline void smap_restore(unsigned long flags)
{
asm volatile ("# smap_restore\n\t"
ALTERNATIVE("", "push %0; popf\n\t",
X86_FEATURE_SMAP)
: : "g" (flags) : "memory", "cc");
}
/* These macros can be used in asm() statements */
#define ASM_CLAC \
ALTERNATIVE("", __ASM_CLAC, X86_FEATURE_SMAP)
#define ASM_STAC \
ALTERNATIVE("", __ASM_STAC, X86_FEATURE_SMAP)
#endif /* __ASSEMBLY__ */
#endif /* _ASM_X86_SMAP_H */