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| author |   Peter Zijlstra <peterz@infradead.org> | 2019-04-03 09:39:48 +0200 |
|---|---|---|
| committer |   Ingo Molnar <mingo@kernel.org> | 2019-04-03 11:02:19 +0200 |
| commit | e74deb11931ff682b59d5b9d387f7115f689698e (patch) | |
| tree | 6d9698ce16b48c95ecff5ca40f8b2701941b9583 | |
| parent | x86/uaccess, signal: Fix AC=1 bloat (diff) | |
| download | linux-dev-e74deb11931ff682b59d5b9d387f7115f689698e.tar.xz linux-dev-e74deb11931ff682b59d5b9d387f7115f689698e.zip | |
x86/uaccess: Introduce user_access_{save,restore}()
Introduce common helpers for when we need to safely suspend a
uaccess section; for instance to generate a {KA,UB}SAN report.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to '')
| -rw-r--r-- | arch/x86/include/asm/smap.h | 20 | ||||
| -rw-r--r-- | arch/x86/include/asm/uaccess.h | 3 | ||||
| -rw-r--r-- | include/linux/uaccess.h | 2 |
3 files changed, 25 insertions, 0 deletions
diff --git a/arch/x86/include/asm/smap.h b/arch/x86/include/asm/smap.h index db333300bd4b..6cfe43171020 100644 --- a/arch/x86/include/asm/smap.h +++ b/arch/x86/include/asm/smap.h @@ -58,6 +58,23 @@ static __always_inline void stac(void) alternative("", __stringify(__ASM_STAC), X86_FEATURE_SMAP); } +static __always_inline unsigned long smap_save(void) +{ + unsigned long flags; + + asm volatile (ALTERNATIVE("", "pushf; pop %0; " __stringify(__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) @@ -69,6 +86,9 @@ static __always_inline void stac(void) 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 diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h index ae5783b5fab0..5ca7b91faf67 100644 --- a/arch/x86/include/asm/uaccess.h +++ b/arch/x86/include/asm/uaccess.h @@ -715,6 +715,9 @@ static __must_check __always_inline bool user_access_begin(const void __user *pt #define user_access_begin(a,b) user_access_begin(a,b) #define user_access_end() __uaccess_end() +#define user_access_save() smap_save() +#define user_access_restore(x) smap_restore(x) + #define unsafe_put_user(x, ptr, label) \ __put_user_size((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)), label) diff --git a/include/linux/uaccess.h b/include/linux/uaccess.h index 37b226e8df13..2b70130af585 100644 --- a/include/linux/uaccess.h +++ b/include/linux/uaccess.h @@ -268,6 +268,8 @@ extern long strncpy_from_unsafe(char *dst, const void *unsafe_addr, long count); #define user_access_end() do { } while (0) #define unsafe_get_user(x, ptr, err) do { if (unlikely(__get_user(x, ptr))) goto err; } while (0) #define unsafe_put_user(x, ptr, err) do { if (unlikely(__put_user(x, ptr))) goto err; } while (0) +static inline unsigned long user_access_save(void) { return 0UL; } +static inline void user_access_restore(unsigned long flags) { } #endif #ifdef CONFIG_HARDENED_USERCOPY |