[PATCH v2 cmpxchg 04/13] sparc32: add __cmpxchg_u{8,16}() and teach __cmpxchg() to handle those sizes

Paul E. McKenney
2024-05-01T23:01:32Z

From: Al Viro <viro@zeniv.linux.org.uk>

trivial now

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
arch/sparc/include/asm/cmpxchg_32.h | 16 +++++++---------
arch/sparc/lib/atomic32.c | 4 ++++
2 files changed, 11 insertions(+), 9 deletions(-)

diff --git a/arch/sparc/include/asm/cmpxchg_32.h b/arch/sparc/include/asm/cmpxchg_32.h
index 05d5f86a56dc2..8c1a3ca34eeb7 100644
--- a/arch/sparc/include/asm/cmpxchg_32.h
+++ b/arch/sparc/include/asm/cmpxchg_32.h
@@ -38,21 +38,19 @@ static __always_inline unsigned long __arch_xchg(unsigned long x, __volatile__ v

/* bug catcher for when unsupported size is used - won't link */
void __cmpxchg_called_with_bad_pointer(void);
-/* we only need to support cmpxchg of a u32 on sparc */
+u8 __cmpxchg_u8(volatile u8 *m, u8 old, u8 new_);
+u16 __cmpxchg_u16(volatile u16 *m, u16 old, u16 new_);
u32 __cmpxchg_u32(volatile u32 *m, u32 old, u32 new_);

/* don't worry...optimizer will get rid of most of this */
static inline unsigned long
__cmpxchg(volatile void *ptr, unsigned long old, unsigned long new_, int size)
{
- switch (size) {
- case 4:
- return __cmpxchg_u32(ptr, old, new_);
- default:
- __cmpxchg_called_with_bad_pointer();
- break;
- }
- return old;
+ return
+ size == 1 ? __cmpxchg_u8(ptr, old, new_) :
+ size == 2 ? __cmpxchg_u16(ptr, old, new_) :
+ size == 4 ? __cmpxchg_u32(ptr, old, new_) :
+ (__cmpxchg_called_with_bad_pointer(), old);
}

#define arch_cmpxchg(ptr, o, n) \
diff --git a/arch/sparc/lib/atomic32.c b/arch/sparc/lib/atomic32.c
index 0d215a772428e..8ae880ebf07aa 100644
--- a/arch/sparc/lib/atomic32.c
+++ b/arch/sparc/lib/atomic32.c
@@ -173,8 +173,12 @@ EXPORT_SYMBOL(sp32___change_bit);
return prev; \
}

+CMPXCHG(u8)
+CMPXCHG(u16)
CMPXCHG(u32)
CMPXCHG(u64)
+EXPORT_SYMBOL(__cmpxchg_u8);
+EXPORT_SYMBOL(__cmpxchg_u16);
EXPORT_SYMBOL(__cmpxchg_u32);
EXPORT_SYMBOL(__cmpxchg_u64);

--
2.40.1