diff options
Diffstat (limited to 'arch/x86/include/asm/smap.h')
| -rw-r--r-- | arch/x86/include/asm/smap.h | 43 |
1 files changed, 29 insertions, 14 deletions
diff --git a/arch/x86/include/asm/smap.h b/arch/x86/include/asm/smap.h index db333300bd4b..27c47d183f4b 100644 --- a/arch/x86/include/asm/smap.h +++ b/arch/x86/include/asm/smap.h @@ -1,25 +1,20 @@ +/* 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> - * - * This program is free software; you can redistribute it and/or - * modify it under the terms of the GNU General Public License - * as published by the Free Software Foundation; version 2 - * of the License. */ #ifndef _ASM_X86_SMAP_H #define _ASM_X86_SMAP_H -#include <linux/stringify.h> #include <asm/nops.h> #include <asm/cpufeatures.h> /* "Raw" instruction opcodes */ -#define __ASM_CLAC .byte 0x0f,0x01,0xca -#define __ASM_STAC .byte 0x0f,0x01,0xcb +#define __ASM_CLAC ".byte 0x0f,0x01,0xca" +#define __ASM_STAC ".byte 0x0f,0x01,0xcb" #ifdef __ASSEMBLY__ @@ -28,10 +23,10 @@ #ifdef CONFIG_X86_SMAP #define ASM_CLAC \ - ALTERNATIVE "", __stringify(__ASM_CLAC), X86_FEATURE_SMAP + ALTERNATIVE "", __ASM_CLAC, X86_FEATURE_SMAP #define ASM_STAC \ - ALTERNATIVE "", __stringify(__ASM_STAC), X86_FEATURE_SMAP + ALTERNATIVE "", __ASM_STAC, X86_FEATURE_SMAP #else /* CONFIG_X86_SMAP */ @@ -49,26 +44,46 @@ static __always_inline void clac(void) { /* Note: a barrier is implicit in alternative() */ - alternative("", __stringify(__ASM_CLAC), X86_FEATURE_SMAP); + alternative("", __ASM_CLAC, X86_FEATURE_SMAP); } static __always_inline void stac(void) { /* Note: a barrier is implicit in alternative() */ - alternative("", __stringify(__ASM_STAC), X86_FEATURE_SMAP); + alternative("", __ASM_STAC, X86_FEATURE_SMAP); +} + +static __always_inline unsigned long smap_save(void) +{ + unsigned long flags; + + asm volatile (ALTERNATIVE("", "pushf; pop %0; " __ASM_CLAC, + X86_FEATURE_SMAP) + : "=rm" (flags) : : "memory", "cc"); + + return flags; +} + +static __always_inline void smap_restore(unsigned long flags) +{ + asm volatile (ALTERNATIVE("", "push %0; popf", X86_FEATURE_SMAP) + : : "g" (flags) : "memory", "cc"); } /* These macros can be used in asm() statements */ #define ASM_CLAC \ - ALTERNATIVE("", __stringify(__ASM_CLAC), X86_FEATURE_SMAP) + ALTERNATIVE("", __ASM_CLAC, X86_FEATURE_SMAP) #define ASM_STAC \ - ALTERNATIVE("", __stringify(__ASM_STAC), X86_FEATURE_SMAP) + ALTERNATIVE("", __ASM_STAC, X86_FEATURE_SMAP) #else /* CONFIG_X86_SMAP */ static inline void clac(void) { } static inline void stac(void) { } +static inline unsigned long smap_save(void) { return 0; } +static inline void smap_restore(unsigned long flags) { } + #define ASM_CLAC #define ASM_STAC |