Commit 4d752e5af637 for kernel

commit 4d752e5af63753ab5140fc282929b98eaa4bd12e
Author: Gao Xiang <hsiangkao@redhat.com>
Date:   Tue Apr 6 12:59:29 2021 +0800

    parisc: avoid a warning on u8 cast for cmpxchg on u8 pointers

    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>

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;