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027ea4f5f2
Back when we added SMAP support, all versions of binutils didn't necessarily understand the 'clac' and 'stac' instructions. So we implemented those instructions manually as ".byte" sequences. But we've since upgraded the minimum version of binutils to version 2.25, and that included proper support for the SMAP instructions, and there's no reason for us to use some line noise to express them any more. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
67 lines
1.4 KiB
C
67 lines
1.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* Supervisor Mode Access Prevention support
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*
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* Copyright (C) 2012 Intel Corporation
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* Author: H. Peter Anvin <hpa@linux.intel.com>
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*/
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#ifndef _ASM_X86_SMAP_H
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#define _ASM_X86_SMAP_H
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#include <asm/nops.h>
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#include <asm/cpufeatures.h>
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#include <asm/alternative.h>
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#ifdef __ASSEMBLY__
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#define ASM_CLAC \
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ALTERNATIVE "", "clac", X86_FEATURE_SMAP
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#define ASM_STAC \
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ALTERNATIVE "", "stac", X86_FEATURE_SMAP
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#else /* __ASSEMBLY__ */
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static __always_inline void clac(void)
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{
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/* Note: a barrier is implicit in alternative() */
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alternative("", "clac", X86_FEATURE_SMAP);
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}
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static __always_inline void stac(void)
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{
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/* Note: a barrier is implicit in alternative() */
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alternative("", "stac", X86_FEATURE_SMAP);
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}
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static __always_inline unsigned long smap_save(void)
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{
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unsigned long flags;
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asm volatile ("# smap_save\n\t"
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ALTERNATIVE("", "pushf; pop %0; " "clac" "\n\t",
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X86_FEATURE_SMAP)
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: "=rm" (flags) : : "memory", "cc");
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return flags;
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}
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static __always_inline void smap_restore(unsigned long flags)
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{
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asm volatile ("# smap_restore\n\t"
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ALTERNATIVE("", "push %0; popf\n\t",
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X86_FEATURE_SMAP)
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: : "g" (flags) : "memory", "cc");
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}
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/* These macros can be used in asm() statements */
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#define ASM_CLAC \
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ALTERNATIVE("", "clac", X86_FEATURE_SMAP)
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#define ASM_STAC \
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ALTERNATIVE("", "stac", X86_FEATURE_SMAP)
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#endif /* __ASSEMBLY__ */
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#endif /* _ASM_X86_SMAP_H */
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