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dbae0a934f
Those were added as part of the SMAP enablement but SMAP is currently an integral part of kernel proper and there's no need to disable it anymore. Rip out that functionality. Leave --uaccess default on for objtool as this is what objtool should do by default anyway. If still needed - clearcpuid=smap. Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com> Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20220127115626.14179-4-bp@alien8.de
70 lines
1.6 KiB
C
70 lines
1.6 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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/* "Raw" instruction opcodes */
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#define __ASM_CLAC ".byte 0x0f,0x01,0xca"
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#define __ASM_STAC ".byte 0x0f,0x01,0xcb"
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#ifdef __ASSEMBLY__
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#define ASM_CLAC \
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ALTERNATIVE "", __ASM_CLAC, X86_FEATURE_SMAP
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#define ASM_STAC \
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ALTERNATIVE "", __ASM_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("", __ASM_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("", __ASM_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; " __ASM_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("", __ASM_CLAC, X86_FEATURE_SMAP)
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#define ASM_STAC \
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ALTERNATIVE("", __ASM_STAC, X86_FEATURE_SMAP)
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#endif /* __ASSEMBLY__ */
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#endif /* _ASM_X86_SMAP_H */
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