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atomic: Skip alignment check for try_cmpxchg() old arg

The 'old' argument in atomic_try_cmpxchg() and related functions is a
pointer to a normal non-atomic integer number, which does not require
to be naturally aligned, unlike the atomic_t/atomic64_t types themselves.

In order to add an alignment check with CONFIG_DEBUG_ATOMIC into the
normal instrument_atomic_read_write() helper, change this check to use
the non-atomic instrument_read_write(), the same way that was done
earlier for try_cmpxchg() in commit ec570320b09f ("locking/atomic:
Correct (cmp)xchg() instrumentation").

This prevents warnings on m68k calling the 32-bit atomic_try_cmpxchg()
with 16-bit aligned arguments as well as several more architectures
including x86-32 when calling atomic64_try_cmpxchg() with 32-bit
aligned u64 arguments.

Reported-by: Finn Thain <fthain@linux-m68k.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/cover.1757810729.git.fthain@linux-m68k.org/

authored by

Arnd Bergmann and committed by
Peter Zijlstra 44472d1b 66f1ea83

+20 -17
+13 -13
include/linux/atomic/atomic-instrumented.h
··· 1276 1276 { 1277 1277 kcsan_mb(); 1278 1278 instrument_atomic_read_write(v, sizeof(*v)); 1279 - instrument_atomic_read_write(old, sizeof(*old)); 1279 + instrument_read_write(old, sizeof(*old)); 1280 1280 return raw_atomic_try_cmpxchg(v, old, new); 1281 1281 } 1282 1282 ··· 1298 1298 atomic_try_cmpxchg_acquire(atomic_t *v, int *old, int new) 1299 1299 { 1300 1300 instrument_atomic_read_write(v, sizeof(*v)); 1301 - instrument_atomic_read_write(old, sizeof(*old)); 1301 + instrument_read_write(old, sizeof(*old)); 1302 1302 return raw_atomic_try_cmpxchg_acquire(v, old, new); 1303 1303 } 1304 1304 ··· 1321 1321 { 1322 1322 kcsan_release(); 1323 1323 instrument_atomic_read_write(v, sizeof(*v)); 1324 - instrument_atomic_read_write(old, sizeof(*old)); 1324 + instrument_read_write(old, sizeof(*old)); 1325 1325 return raw_atomic_try_cmpxchg_release(v, old, new); 1326 1326 } 1327 1327 ··· 1343 1343 atomic_try_cmpxchg_relaxed(atomic_t *v, int *old, int new) 1344 1344 { 1345 1345 instrument_atomic_read_write(v, sizeof(*v)); 1346 - instrument_atomic_read_write(old, sizeof(*old)); 1346 + instrument_read_write(old, sizeof(*old)); 1347 1347 return raw_atomic_try_cmpxchg_relaxed(v, old, new); 1348 1348 } 1349 1349 ··· 2854 2854 { 2855 2855 kcsan_mb(); 2856 2856 instrument_atomic_read_write(v, sizeof(*v)); 2857 - instrument_atomic_read_write(old, sizeof(*old)); 2857 + instrument_read_write(old, sizeof(*old)); 2858 2858 return raw_atomic64_try_cmpxchg(v, old, new); 2859 2859 } 2860 2860 ··· 2876 2876 atomic64_try_cmpxchg_acquire(atomic64_t *v, s64 *old, s64 new) 2877 2877 { 2878 2878 instrument_atomic_read_write(v, sizeof(*v)); 2879 - instrument_atomic_read_write(old, sizeof(*old)); 2879 + instrument_read_write(old, sizeof(*old)); 2880 2880 return raw_atomic64_try_cmpxchg_acquire(v, old, new); 2881 2881 } 2882 2882 ··· 2899 2899 { 2900 2900 kcsan_release(); 2901 2901 instrument_atomic_read_write(v, sizeof(*v)); 2902 - instrument_atomic_read_write(old, sizeof(*old)); 2902 + instrument_read_write(old, sizeof(*old)); 2903 2903 return raw_atomic64_try_cmpxchg_release(v, old, new); 2904 2904 } 2905 2905 ··· 2921 2921 atomic64_try_cmpxchg_relaxed(atomic64_t *v, s64 *old, s64 new) 2922 2922 { 2923 2923 instrument_atomic_read_write(v, sizeof(*v)); 2924 - instrument_atomic_read_write(old, sizeof(*old)); 2924 + instrument_read_write(old, sizeof(*old)); 2925 2925 return raw_atomic64_try_cmpxchg_relaxed(v, old, new); 2926 2926 } 2927 2927 ··· 4432 4432 { 4433 4433 kcsan_mb(); 4434 4434 instrument_atomic_read_write(v, sizeof(*v)); 4435 - instrument_atomic_read_write(old, sizeof(*old)); 4435 + instrument_read_write(old, sizeof(*old)); 4436 4436 return raw_atomic_long_try_cmpxchg(v, old, new); 4437 4437 } 4438 4438 ··· 4454 4454 atomic_long_try_cmpxchg_acquire(atomic_long_t *v, long *old, long new) 4455 4455 { 4456 4456 instrument_atomic_read_write(v, sizeof(*v)); 4457 - instrument_atomic_read_write(old, sizeof(*old)); 4457 + instrument_read_write(old, sizeof(*old)); 4458 4458 return raw_atomic_long_try_cmpxchg_acquire(v, old, new); 4459 4459 } 4460 4460 ··· 4477 4477 { 4478 4478 kcsan_release(); 4479 4479 instrument_atomic_read_write(v, sizeof(*v)); 4480 - instrument_atomic_read_write(old, sizeof(*old)); 4480 + instrument_read_write(old, sizeof(*old)); 4481 4481 return raw_atomic_long_try_cmpxchg_release(v, old, new); 4482 4482 } 4483 4483 ··· 4499 4499 atomic_long_try_cmpxchg_relaxed(atomic_long_t *v, long *old, long new) 4500 4500 { 4501 4501 instrument_atomic_read_write(v, sizeof(*v)); 4502 - instrument_atomic_read_write(old, sizeof(*old)); 4502 + instrument_read_write(old, sizeof(*old)); 4503 4503 return raw_atomic_long_try_cmpxchg_relaxed(v, old, new); 4504 4504 } 4505 4505 ··· 5050 5050 5051 5051 5052 5052 #endif /* _LINUX_ATOMIC_INSTRUMENTED_H */ 5053 - // 8829b337928e9508259079d32581775ececd415b 5053 + // f618ac667f868941a84ce0ab2242f1786e049ed4
+7 -4
scripts/atomic/gen-atomic-instrumented.sh
··· 12 12 local arg="$1"; shift 13 13 local type="${arg%%:*}" 14 14 local name="$(gen_param_name "${arg}")" 15 - local rw="write" 15 + local rw="atomic_write" 16 16 17 17 case "${type#c}" in 18 18 i) return;; ··· 20 20 21 21 if [ ${type#c} != ${type} ]; then 22 22 # We don't write to constant parameters. 23 - rw="read" 23 + rw="atomic_read" 24 + elif [ "${type}" = "p" ] ; then 25 + # The "old" argument in try_cmpxchg() gets accessed non-atomically 26 + rw="read_write" 24 27 elif [ "${meta}" != "s" ]; then 25 28 # An atomic RMW: if this parameter is not a constant, and this atomic is 26 29 # not just a 's'tore, this parameter is both read from and written to. 27 - rw="read_write" 30 + rw="atomic_read_write" 28 31 fi 29 32 30 - printf "\tinstrument_atomic_${rw}(${name}, sizeof(*${name}));\n" 33 + printf "\tinstrument_${rw}(${name}, sizeof(*${name}));\n" 31 34 } 32 35 33 36 #gen_params_checks(meta, arg...)