diff options
| author | Will Deacon <will@kernel.org> | 2020-05-12 10:01:01 +0100 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2020-05-13 14:17:09 +0200 |
| commit | ffed638b6a2180da8fd002a46632d746af72b299 (patch) | |
| tree | bc042f1790f46eeaea90dcdcf5ddec297325df12 | |
| parent | 6bcc8f459fe790f35dfd8e3bb0f43e530d44ee9a (diff) | |
READ_ONCE: Fix comment describing 2x32-bit atomicitynoinstr-kcsan-2020-05015
READ_ONCE() permits 64-bit accesses on 32-bit architectures, since this
crops up in a few places and is generally harmless because either the
upper bits are always zero (e.g. for a virtual address or 32-bit time_t)
or the architecture provides 64-bit atomicity anyway.
Update the corresponding comment above compiletime_assert_rwonce_type(),
which incorrectly states that 32-bit x86 provides 64-bit atomicity, and
instead reference 32-bit Armv7 with LPAE.
Reported-by: Jann Horn <jannh@google.com>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200512090101.2497-1-will@kernel.org
| -rw-r--r-- | include/linux/compiler.h | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/include/linux/compiler.h b/include/linux/compiler.h index 741c93c62ecf..e24cc3a2bc3e 100644 --- a/include/linux/compiler.h +++ b/include/linux/compiler.h @@ -384,9 +384,9 @@ static inline void *offset_to_ptr(const int *off) /* * Yes, this permits 64-bit accesses on 32-bit architectures. These will - * actually be atomic in many cases (namely x86), but for others we rely on - * the access being split into 2x32-bit accesses for a 32-bit quantity (e.g. - * a virtual address) and a strong prevailing wind. + * actually be atomic in some cases (namely Armv7 + LPAE), but for others we + * rely on the access being split into 2x32-bit accesses for a 32-bit quantity + * (e.g. a virtual address) and a strong prevailing wind. */ #define compiletime_assert_rwonce_type(t) \ compiletime_assert(__native_word(t) || sizeof(t) == sizeof(long long), \ |