74 lines
1.7 KiB
C
74 lines
1.7 KiB
C
/* 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>
|
|
|
|
#ifdef __ASSEMBLY__
|
|
|
|
#define ASM_CLAC \
|
|
ALTERNATIVE "", "clac", X86_FEATURE_SMAP
|
|
|
|
#define ASM_STAC \
|
|
ALTERNATIVE "", "stac", X86_FEATURE_SMAP
|
|
|
|
#else /* __ASSEMBLY__ */
|
|
|
|
static __always_inline void clac(void)
|
|
{
|
|
/* Note: a barrier is implicit in alternative() */
|
|
alternative("", "clac", X86_FEATURE_SMAP);
|
|
}
|
|
|
|
static __always_inline void stac(void)
|
|
{
|
|
/* Note: a barrier is implicit in alternative() */
|
|
alternative("", "stac", X86_FEATURE_SMAP);
|
|
}
|
|
|
|
static __always_inline unsigned long smap_save(void)
|
|
{
|
|
unsigned long flags;
|
|
|
|
asm volatile ("# smap_save\n\t"
|
|
ALTERNATIVE(ANNOTATE_IGNORE_ALTERNATIVE
|
|
"", "pushf; pop %0; clac",
|
|
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(ANNOTATE_IGNORE_ALTERNATIVE
|
|
"", "push %0; popf",
|
|
X86_FEATURE_SMAP)
|
|
: : "g" (flags) : "memory", "cc");
|
|
}
|
|
|
|
/* These macros can be used in asm() statements */
|
|
#define ASM_CLAC \
|
|
ALTERNATIVE("", "clac", X86_FEATURE_SMAP)
|
|
#define ASM_STAC \
|
|
ALTERNATIVE("", "stac", X86_FEATURE_SMAP)
|
|
|
|
#define ASM_CLAC_UNSAFE \
|
|
ALTERNATIVE("", ANNOTATE_IGNORE_ALTERNATIVE "clac", X86_FEATURE_SMAP)
|
|
#define ASM_STAC_UNSAFE \
|
|
ALTERNATIVE("", ANNOTATE_IGNORE_ALTERNATIVE "stac", X86_FEATURE_SMAP)
|
|
|
|
#endif /* __ASSEMBLY__ */
|
|
|
|
#endif /* _ASM_X86_SMAP_H */
|