sparc64: Stop using memory barriers for atomics and locks.

The kernel always executes in the TSO memory model now,
so none of this stuff is necessary any more.

With helpful feedback from Nick Piggin.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 8 insertions, 27 deletions

diff --git a/arch/sparc/include/asm/system_64.h b/arch/sparc/include/asm/system_64.h
index 8759f2a1b837..7554ad39b5af 100644
--- a/arch/sparc/include/asm/system_64.h
+++ b/arch/sparc/include/asm/system_64.h
@@ -59,20 +59,9 @@ do {	__asm__ __volatile__("ba,pt	%%xcc, 1f\n\t" \
                              : : : "memory"); \
 } while (0)
 
-#define mb()    \
-        membar_safe("#LoadLoad | #LoadStore | #StoreStore | #StoreLoad")
-#define rmb()   \
-        membar_safe("#LoadLoad")
-#define wmb()   \
-        membar_safe("#StoreStore")
-#define membar_storeload() \
-        membar_safe("#StoreLoad")
-#define membar_storeload_storestore() \
-        membar_safe("#StoreLoad | #StoreStore")
-#define membar_storeload_loadload() \
-        membar_safe("#StoreLoad | #LoadLoad")
-#define membar_storestore_loadstore() \
-        membar_safe("#StoreStore | #LoadStore")
+#define mb()    membar_safe("#StoreLoad")
+#define rmb()   __asm__ __volatile__("":::"memory")
+#define wmb()   __asm__ __volatile__("":::"memory")
 
 #endif
 
@@ -80,20 +69,20 @@ do {	__asm__ __volatile__("ba,pt	%%xcc, 1f\n\t" \
 
 #define read_barrier_depends()          do { } while(0)
 #define set_mb(__var, __value) \
-        do { __var = __value; membar_storeload_storestore(); } while(0)
+        do { __var = __value; membar_safe("#StoreLoad"); } while(0)
 
 #ifdef CONFIG_SMP
 #define smp_mb()        mb()
 #define smp_rmb()       rmb()
 #define smp_wmb()       wmb()
-#define smp_read_barrier_depends()      read_barrier_depends()
 #else
 #define smp_mb()        __asm__ __volatile__("":::"memory")
 #define smp_rmb()       __asm__ __volatile__("":::"memory")
 #define smp_wmb()       __asm__ __volatile__("":::"memory")
-#define smp_read_barrier_depends()      do { } while(0)
 #endif
 
+#define smp_read_barrier_depends()      do { } while(0)
+
 #define flushi(addr)    __asm__ __volatile__ ("flush %0" : : "r" (addr) : "memory")
 
 #define flushw_all()    __asm__ __volatile__("flushw")
@@ -209,14 +198,12 @@ static inline unsigned long xchg32(__volatile__ unsigned int *m, unsigned int va
         unsigned long tmp1, tmp2;
 
         __asm__ __volatile__(
-"       membar          #StoreLoad | #LoadLoad\n"
 "       mov             %0, %1\n"
 "1:     lduw            [%4], %2\n"
 "       cas             [%4], %2, %0\n"
 "       cmp             %2, %0\n"
 "       bne,a,pn        %%icc, 1b\n"
 "        mov            %1, %0\n"
-"       membar          #StoreLoad | #StoreStore\n"
         : "=&r" (val), "=&r" (tmp1), "=&r" (tmp2)
         : "0" (val), "r" (m)
         : "cc", "memory");
@@ -228,14 +215,12 @@ static inline unsigned long xchg64(__volatile__ unsigned long *m, unsigned long
         unsigned long tmp1, tmp2;
 
         __asm__ __volatile__(
-"       membar          #StoreLoad | #LoadLoad\n"
 "       mov             %0, %1\n"
 "1:     ldx             [%4], %2\n"
 "       casx            [%4], %2, %0\n"
 "       cmp             %2, %0\n"
 "       bne,a,pn        %%xcc, 1b\n"
 "        mov            %1, %0\n"
-"       membar          #StoreLoad | #StoreStore\n"
         : "=&r" (val), "=&r" (tmp1), "=&r" (tmp2)
         : "0" (val), "r" (m)
         : "cc", "memory");
@@ -272,9 +257,7 @@ extern void die_if_kernel(char *str, struct pt_regs *regs) __attribute__ ((noret
 static inline unsigned long
 __cmpxchg_u32(volatile int *m, int old, int new)
 {
-        __asm__ __volatile__("membar #StoreLoad | #LoadLoad\n"
-                             "cas [%2], %3, %0\n\t"
-                             "membar #StoreLoad | #StoreStore"
+        __asm__ __volatile__("cas [%2], %3, %0"
                              : "=&r" (new)
                              : "0" (new), "r" (m), "r" (old)
                              : "memory");
@@ -285,9 +268,7 @@ __cmpxchg_u32(volatile int *m, int old, int new)
 static inline unsigned long
 __cmpxchg_u64(volatile long *m, unsigned long old, unsigned long new)
 {
-        __asm__ __volatile__("membar #StoreLoad | #LoadLoad\n"
-                             "casx [%2], %3, %0\n\t"
-                             "membar #StoreLoad | #StoreStore"
+        __asm__ __volatile__("casx [%2], %3, %0"
                              : "=&r" (new)
                              : "0" (new), "r" (m), "r" (old)
                              : "memory");