4.20-stable review patch. If anyone has any objections, please let me know.
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From: Michael Clark michaeljclark@mac.com
commit 94ee12b507db8b5876e31c9d6c9d84f556a4b49f upstream.
__cmpxchg_small erroneously uses u8 for load comparison which can be either char or short. This patch changes the local variable to u32 which is sufficiently sized, as the loaded value is already masked and shifted appropriately. Using an integer size avoids any unnecessary canonicalization from use of non native widths.
This patch is part of a series that adapts the MIPS small word atomics code for xchg and cmpxchg on short and char to RISC-V.
Cc: RISC-V Patches patches@groups.riscv.org Cc: Linux RISC-V linux-riscv@lists.infradead.org Cc: Linux MIPS linux-mips@linux-mips.org Signed-off-by: Michael Clark michaeljclark@mac.com [paul.burton@mips.com: - Fix varialble typo per Jonas Gorski. - Consolidate load variable with other declarations.] Signed-off-by: Paul Burton paul.burton@mips.com Fixes: 3ba7f44d2b19 ("MIPS: cmpxchg: Implement 1 byte & 2 byte cmpxchg()") Cc: stable@vger.kernel.org # v4.13+ Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/mips/kernel/cmpxchg.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
--- a/arch/mips/kernel/cmpxchg.c +++ b/arch/mips/kernel/cmpxchg.c @@ -54,10 +54,9 @@ unsigned long __xchg_small(volatile void unsigned long __cmpxchg_small(volatile void *ptr, unsigned long old, unsigned long new, unsigned int size) { - u32 mask, old32, new32, load32; + u32 mask, old32, new32, load32, load; volatile u32 *ptr32; unsigned int shift; - u8 load;
/* Check that ptr is naturally aligned */ WARN_ON((unsigned long)ptr & (size - 1));