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xtensa: Emulate one-byte cmpxchg

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Use the new cmpxchg_emu_u8() to emulate one-byte cmpxchg() on xtensa.

[ paulmck: Apply kernel test robot feedback. ]
[ paulmck: Drop two-byte support per Arnd Bergmann feedback. ]
[ Apply Geert Uytterhoeven feedback. ]

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Tested-by: Yujie Liu <yujie.liu@intel.com>
Cc: Andi Shyti <andi.shyti@linux.intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>
This commit is contained in:
Paul E. McKenney 2024-03-27 15:28:04 -07:00
parent c81a748ede
commit e799bef0d9
2 changed files with 3 additions and 0 deletions
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1
arch/xtensa/Kconfig
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@ -14,6 +14,7 @@ config XTENSA
select ARCH_HAS_DMA_SET_UNCACHED if MMU
select ARCH_HAS_STRNCPY_FROM_USER if !KASAN
select ARCH_HAS_STRNLEN_USER
select ARCH_NEED_CMPXCHG_1_EMU
select ARCH_USE_MEMTEST
select ARCH_USE_QUEUED_RWLOCKS
select ARCH_USE_QUEUED_SPINLOCKS

2
arch/xtensa/include/asm/cmpxchg.h
View File

@ -15,6 +15,7 @@
#include <linux/bits.h>
#include <linux/stringify.h>
#include <linux/cmpxchg-emu.h>
/*
* cmpxchg
@ -74,6 +75,7 @@ static __inline__ unsigned long
__cmpxchg(volatile void *ptr, unsigned long old, unsigned long new, int size)
{
switch (size) {
case 1: return cmpxchg_emu_u8(ptr, old, new);
case 4: return __cmpxchg_u32(ptr, old, new);
default: __cmpxchg_called_with_bad_pointer();
return old;