The __xchg_u32() & __xchg_u64() functions now add very little value.
This patch therefore removes them, by:
- Moving memory barriers out of them & into xchg(), which also removes
the duplication & readies us to support xchg_relaxed() if we wish to.
- Calling __xchg_asm() directly from __xchg().
- Performing the check for CONFIG_64BIT being enabled in the size=8
case of __xchg().
Signed-off-by: Paul Burton <paul.burton@xxxxxxxxxx>
Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Cc: linux-mips@xxxxxxxxxxxxxx
---
arch/mips/include/asm/cmpxchg.h | 48 +++++++++++++++--------------------------
1 file changed, 17 insertions(+), 31 deletions(-)
diff --git a/arch/mips/include/asm/cmpxchg.h b/arch/mips/include/asm/cmpxchg.h
index fe652c3e5d8c..e9c1e97bc29d 100644
--- a/arch/mips/include/asm/cmpxchg.h
+++ b/arch/mips/include/asm/cmpxchg.h
@@ -70,40 +70,18 @@ extern unsigned long __xchg_called_with_bad_pointer(void)
__ret; \
})
-static inline unsigned long __xchg_u32(volatile int * m, unsigned int val)
-{
- __u32 retval;
-
- smp_mb__before_llsc();
- retval = __xchg_asm("ll", "sc", m, val);
- smp_llsc_mb();
-
- return retval;
-}
-
-#ifdef CONFIG_64BIT
-static inline __u64 __xchg_u64(volatile __u64 * m, __u64 val)
-{
- __u64 retval;
-
- smp_mb__before_llsc();
- retval = __xchg_asm("lld", "scd", m, val);
- smp_llsc_mb();
-
- return retval;
-}
-#else
-extern __u64 __xchg_u64_unsupported_on_32bit_kernels(volatile __u64 * m, __u64 val);
-#define __xchg_u64 __xchg_u64_unsupported_on_32bit_kernels
-#endif
-
static inline unsigned long __xchg(unsigned long x, volatile void * ptr, int size)
{
switch (size) {
case 4:
- return __xchg_u32(ptr, x);
+ return __xchg_asm("ll", "sc", (volatile u32 *)ptr, x);
+
case 8:
- return __xchg_u64(ptr, x);
+ if (!IS_ENABLED(CONFIG_64BIT))
+ return __xchg_called_with_bad_pointer();
+
+ return __xchg_asm("lld", "scd", (volatile u64 *)ptr, x);
+
default:
return __xchg_called_with_bad_pointer();
}
@@ -111,10 +89,18 @@ static inline unsigned long __xchg(unsigned long x, volatile void * ptr, int siz
#define xchg(ptr, x) \
({ \
+ __typeof__(*(ptr)) __res; \
+ \
BUILD_BUG_ON(sizeof(*(ptr)) & ~0xc); \
\
- ((__typeof__(*(ptr))) \
- __xchg((unsigned long)(x), (ptr), sizeof(*(ptr)))); \
+ smp_mb__before_llsc(); \
+ \
+ __res = (__typeof__(*(ptr))) \
+ __xchg((unsigned long)(x), (ptr), sizeof(*(ptr))); \
+ \
+ smp_llsc_mb(); \
+ \
+ __res; \
})
#define __cmpxchg_asm(ld, st, m, old, new) \
--
2.13.1
