diff options
| author | Sasha Levin <sashal@kernel.org> | 2025-07-02 18:01:44 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-07-06 11:01:49 +0200 |
| commit | 1fc00e145172068ddeb56275c3db1fbd6ae4dddf (patch) | |
| tree | 9242064069db6fb5521a9a2c3f39efa415d6e23b | |
| parent | fbbb0e0de97f6e00bbe5c2d6dc417011c235bef1 (diff) | |
riscv/atomic: Do proper sign extension also for unsigned in arch_cmpxchg
[ Upstream commit 1898300abf3508bca152e65b36cce5bf93d7e63e ]
Sign extend also an unsigned compare value to match what lr.w is doing.
Otherwise try_cmpxchg may spuriously return true when used on a u32 value
that has the sign bit set, as it happens often in inode_set_ctime_current.
Do this in three conversion steps. The first conversion to long is needed
to avoid a -Wpointer-to-int-cast warning when arch_cmpxchg is used with a
pointer type. Then convert to int and back to long to always sign extend
the 32-bit value to 64-bit.
Fixes: 6c58f25e6938 ("riscv/atomic: Fix sign extension for RV64I")
Signed-off-by: Andreas Schwab <schwab@suse.de>
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Tested-by: Xi Ruoyao <xry111@xry111.site>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/mvmed0k4prh.fsf@suse.de
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | arch/riscv/include/asm/cmpxchg.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/riscv/include/asm/cmpxchg.h b/arch/riscv/include/asm/cmpxchg.h index ebbce134917c..6efa95ad033a 100644 --- a/arch/riscv/include/asm/cmpxchg.h +++ b/arch/riscv/include/asm/cmpxchg.h @@ -169,7 +169,7 @@ break; \ case 4: \ __arch_cmpxchg(".w", ".w" sc_sfx, prepend, append, \ - __ret, __ptr, (long), __old, __new); \ + __ret, __ptr, (long)(int)(long), __old, __new); \ break; \ case 8: \ __arch_cmpxchg(".d", ".d" sc_sfx, prepend, append, \ |