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97 lines
2.0 KiB
97 lines
2.0 KiB
/* 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 <[email protected]> |
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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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/* "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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#include <asm/alternative-asm.h> |
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#ifdef CONFIG_X86_SMAP |
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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 /* CONFIG_X86_SMAP */ |
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#define ASM_CLAC |
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#define ASM_STAC |
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#endif /* CONFIG_X86_SMAP */ |
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#else /* __ASSEMBLY__ */ |
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#include <asm/alternative.h> |
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#ifdef CONFIG_X86_SMAP |
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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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#else /* CONFIG_X86_SMAP */ |
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static inline void clac(void) { } |
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static inline void stac(void) { } |
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static inline unsigned long smap_save(void) { return 0; } |
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static inline void smap_restore(unsigned long flags) { } |
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#define ASM_CLAC |
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#define ASM_STAC |
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#endif /* CONFIG_X86_SMAP */ |
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#endif /* __ASSEMBLY__ */ |
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#endif /* _ASM_X86_SMAP_H */
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