From 9264678a41467b4c02d139fa296c61e20f6ee566 Mon Sep 17 00:00:00 2001 From: Gao Xiang Date: Wed, 21 Apr 2021 11:31:58 +0000 Subject: [PATCH] parisc: avoid a warning on u8 cast for cmpxchg on u8 pointers MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit stable inclusion from stable-5.10.30 commit 4941889535f36cc8b11d72b96cb24cb972e23d48 bugzilla: 51791 -------------------------------- 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 Cc: Helge Deller Cc: stable@vger.kernel.org # v5.8+ Signed-off-by: Gao Xiang Signed-off-by: Helge Deller Signed-off-by: Greg Kroah-Hartman Signed-off-by: Chen Jun Acked-by:  Weilong Chen Signed-off-by: Zheng Zengkai --- arch/parisc/include/asm/cmpxchg.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/parisc/include/asm/cmpxchg.h b/arch/parisc/include/asm/cmpxchg.h index cf5ee9b0b393..84ee232278a6 100644 --- a/arch/parisc/include/asm/cmpxchg.h +++ b/arch/parisc/include/asm/cmpxchg.h @@ -72,7 +72,7 @@ __cmpxchg(volatile void *ptr, unsigned long old, unsigned long new_, int size) #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; -- GitLab