diff options
| author | Andrey Ryabinin <aryabinin@virtuozzo.com> | 2018-02-01 21:00:49 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-08-04 09:33:32 +0200 |
| commit | 4b5d4bdfd1ea2c2946f55ba309e17440b4ddada2 (patch) | |
| tree | 7998f07cb9a3fcdaf29ead06f752448a08e07d8a | |
| parent | 229b670e66689326c97639b4767c12c33462dac1 (diff) | |
compiler.h: Add read_word_at_a_time() function.
[ Upstream commit 7f1e541fc8d57a143dd5df1d0a1276046e08c083 ]
Sometimes we know that it's safe to do potentially out-of-bounds access
because we know it won't cross a page boundary. Still, KASAN will
report this as a bug.
Add read_word_at_a_time() function which is supposed to be used in such
cases. In read_word_at_a_time() KASAN performs relaxed check - only the
first byte of access is validated.
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | include/linux/compiler.h | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/include/linux/compiler.h b/include/linux/compiler.h index ced454c03819..3050de0dac96 100644 --- a/include/linux/compiler.h +++ b/include/linux/compiler.h @@ -302,6 +302,7 @@ static __always_inline void __write_once_size(volatile void *p, void *res, int s * with an explicit memory barrier or atomic instruction that provides the * required ordering. */ +#include <linux/kasan-checks.h> #define __READ_ONCE(x, check) \ ({ \ @@ -320,6 +321,13 @@ static __always_inline void __write_once_size(volatile void *p, void *res, int s */ #define READ_ONCE_NOCHECK(x) __READ_ONCE(x, 0) +static __no_kasan_or_inline +unsigned long read_word_at_a_time(const void *addr) +{ + kasan_check_read(addr, 1); + return *(unsigned long *)addr; +} + #define WRITE_ONCE(x, val) \ ({ \ union { typeof(x) __val; char __c[1]; } __u = \ |