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;