| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.14 13/68] parisc: avoid a warning on u8 cast for cmpxchg on u8 pointers | Date | Thu, 15 Apr 2021 16:46:54 +0200 |
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From: Gao Xiang <hsiangkao@redhat.com>
commit 4d752e5af63753ab5140fc282929b98eaa4bd12e upstream.
commit b344d6a83d01 ("parisc: add support for cmpxchg on u8 pointers") can generate a sparse warning ("cast truncates bits from constant value"), which has been reported several times [1] [2] [3].
The original code worked as expected, but anyway, let silence such sparse warning as what others did [4].
[1] https://lore.kernel.org/r/202104061220.nRMBwCXw-lkp@intel.com [2] https://lore.kernel.org/r/202012291914.T5Agcn99-lkp@intel.com [3] https://lore.kernel.org/r/202008210829.KVwn7Xeh%25lkp@intel.com [4] https://lore.kernel.org/r/20210315131512.133720-2-jacopo+renesas@jmondi.org Cc: Liam Beguin <liambeguin@gmail.com> Cc: Helge Deller <deller@gmx.de> Cc: stable@vger.kernel.org # v5.8+ Signed-off-by: Gao Xiang <hsiangkao@redhat.com> Signed-off-by: Helge Deller <deller@gmx.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- arch/parisc/include/asm/cmpxchg.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/parisc/include/asm/cmpxchg.h +++ b/arch/parisc/include/asm/cmpxchg.h @@ -72,7 +72,7 @@ __cmpxchg(volatile void *ptr, unsigned l #endif case 4: return __cmpxchg_u32((unsigned int *)ptr, (unsigned int)old, (unsigned int)new_); - case 1: return __cmpxchg_u8((u8 *)ptr, (u8)old, (u8)new_); + case 1: return __cmpxchg_u8((u8 *)ptr, old & 0xff, new_ & 0xff); } __cmpxchg_called_with_bad_pointer(); return old;
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