diff options
| author | Richard Henderson <richard.henderson@linaro.org> | 2021-07-16 08:17:18 -0700 |
|---|---|---|
| committer | Richard Henderson <richard.henderson@linaro.org> | 2021-07-21 07:45:38 -1000 |
| commit | 9ef0c6d6a7d81992a2326416a9ce12eef2824861 (patch) | |
| tree | dc4c99d93f6823e1cca48772a23cd8926bce3ee8 /include | |
| parent | 47345e7124709d280f14551113a20fd81ad2bf20 (diff) | |
qemu/atomic: Add aligned_{int64,uint64}_t types
Use it to avoid some clang-12 -Watomic-alignment errors,
forcing some structures to be aligned and as a pointer when
we have ensured that the address is aligned.
Tested-by: Cole Robinson <crobinso@redhat.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/qemu/atomic.h | 14 | ||||
| -rw-r--r-- | include/qemu/stats64.h | 2 |
2 files changed, 14 insertions, 2 deletions
diff --git a/include/qemu/atomic.h b/include/qemu/atomic.h index fe5467d193..112a29910b 100644 --- a/include/qemu/atomic.h +++ b/include/qemu/atomic.h @@ -271,7 +271,19 @@ _oldn; \ }) -/* Abstractions to access atomically (i.e. "once") i64/u64 variables */ +/* + * Abstractions to access atomically (i.e. "once") i64/u64 variables. + * + * The i386 abi is odd in that by default members are only aligned to + * 4 bytes, which means that 8-byte types can wind up mis-aligned. + * Clang will then warn about this, and emit a call into libatomic. + * + * Use of these types in structures when they will be used with atomic + * operations can avoid this. + */ +typedef int64_t aligned_int64_t __attribute__((aligned(8))); +typedef uint64_t aligned_uint64_t __attribute__((aligned(8))); + #ifdef CONFIG_ATOMIC64 /* Use __nocheck because sizeof(void *) might be < sizeof(u64) */ #define qatomic_read_i64(P) \ diff --git a/include/qemu/stats64.h b/include/qemu/stats64.h index fdd3d1b8f9..802402254b 100644 --- a/include/qemu/stats64.h +++ b/include/qemu/stats64.h @@ -21,7 +21,7 @@ typedef struct Stat64 { #ifdef CONFIG_ATOMIC64 - uint64_t value; + aligned_uint64_t value; #else uint32_t low, high; uint32_t lock; |