diff options
| author | Andrey Ryabinin <aryabinin@virtuozzo.com> | 2018-02-01 21:00:49 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-10-29 09:03:00 +0100 |
| commit | 203ba216f29bfc7378d3595f31daab74fa72f9d7 (patch) | |
| tree | b59f3e15722346b95457005fb377ed041187e070 /include/linux/compiler.h | |
| parent | 36bd2ae6cc1887bd371ca259d433734ae68212f4 (diff) | |
compiler.h: Add read_word_at_a_time() function.
commit 7f1e541fc8d57a143dd5df1d0a1276046e08c083 upstream.
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>
[bwh: Backported to 4.4: adjust context]
Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include/linux/compiler.h')
| -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 92a51e00b904..7cabe0cc8665 100644 --- a/include/linux/compiler.h +++ b/include/linux/compiler.h @@ -292,6 +292,7 @@ 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) \ ({ \ @@ -310,6 +311,13 @@ 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 = \ |