[SPARC64]: More fully work around Spitfire Errata 51.

It appears that a memory barrier soon after a mispredicted
branch, not just in the delay slot, can cause the hang
condition of this cpu errata.

So move them out-of-line, and explicitly put them into
a "branch always, predict taken" delay slot which should
fully kill this problem.

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

4 files changed, 18 insertions, 15 deletions

diff --git a/include/asm-sparc64/atomic.h b/include/asm-sparc64/atomic.h
index d80f3379669b..e175afcf2cde 100644
--- a/include/asm-sparc64/atomic.h
+++ b/include/asm-sparc64/atomic.h
@@ -72,10 +72,10 @@ extern int atomic64_sub_ret(int, atomic64_t *);
 
 /* Atomic operations are already serializing */
 #ifdef CONFIG_SMP
-#define smp_mb__before_atomic_dec()     membar("#StoreLoad | #LoadLoad")
-#define smp_mb__after_atomic_dec()      membar("#StoreLoad | #StoreStore")
-#define smp_mb__before_atomic_inc()     membar("#StoreLoad | #LoadLoad")
-#define smp_mb__after_atomic_inc()      membar("#StoreLoad | #StoreStore")
+#define smp_mb__before_atomic_dec()     membar_storeload_loadload();
+#define smp_mb__after_atomic_dec()      membar_storeload_storestore();
+#define smp_mb__before_atomic_inc()     membar_storeload_loadload();
+#define smp_mb__after_atomic_inc()      membar_storeload_storestore();
 #else
 #define smp_mb__before_atomic_dec()     barrier()
 #define smp_mb__after_atomic_dec()      barrier()
diff --git a/include/asm-sparc64/bitops.h b/include/asm-sparc64/bitops.h
index 9c5e71970287..6388b8376c50 100644
--- a/include/asm-sparc64/bitops.h
+++ b/include/asm-sparc64/bitops.h
@@ -72,8 +72,8 @@ static inline int __test_and_change_bit(int nr, volatile unsigned long *addr)
 }
 
 #ifdef CONFIG_SMP
-#define smp_mb__before_clear_bit()      membar("#StoreLoad | #LoadLoad")
-#define smp_mb__after_clear_bit()       membar("#StoreLoad | #StoreStore")
+#define smp_mb__before_clear_bit()      membar_storeload_loadload()
+#define smp_mb__after_clear_bit()       membar_storeload_storestore()
 #else
 #define smp_mb__before_clear_bit()      barrier()
 #define smp_mb__after_clear_bit()       barrier()
diff --git a/include/asm-sparc64/spinlock.h b/include/asm-sparc64/spinlock.h
index d265bf6570fe..a02c4370eb42 100644
--- a/include/asm-sparc64/spinlock.h
+++ b/include/asm-sparc64/spinlock.h
@@ -43,7 +43,7 @@ typedef struct {
 #define spin_is_locked(lp)  ((lp)->lock != 0)
 
 #define spin_unlock_wait(lp)    \
-do {    membar("#LoadLoad");    \
+do {    rmb();                  \
 } while((lp)->lock)
 
 static inline void _raw_spin_lock(spinlock_t *lock)
@@ -129,7 +129,7 @@ typedef struct {
 #define spin_is_locked(__lock)  ((__lock)->lock != 0)
 #define spin_unlock_wait(__lock)        \
 do { \
-        membar("#LoadLoad"); \
+        rmb(); \
 } while((__lock)->lock)
 
 extern void _do_spin_lock(spinlock_t *lock, char *str, unsigned long caller);
diff --git a/include/asm-sparc64/system.h b/include/asm-sparc64/system.h
index ee4bdfc6b88f..5e94c05dc2fc 100644
--- a/include/asm-sparc64/system.h
+++ b/include/asm-sparc64/system.h
@@ -28,6 +28,14 @@ enum sparc_cpu {
 #define ARCH_SUN4C_SUN4 0
 #define ARCH_SUN4 0
 
+extern void mb(void);
+extern void rmb(void);
+extern void wmb(void);
+extern void membar_storeload(void);
+extern void membar_storeload_storestore(void);
+extern void membar_storeload_loadload(void);
+extern void membar_storestore_loadstore(void);
+
 #endif
 
 #define setipl(__new_ipl) \
@@ -78,16 +86,11 @@ enum sparc_cpu {
 
 #define nop()           __asm__ __volatile__ ("nop")
 
-#define membar(type)    __asm__ __volatile__ ("membar " type : : : "memory")
-#define mb()            \
-        membar("#LoadLoad | #LoadStore | #StoreStore | #StoreLoad")
-#define rmb()           membar("#LoadLoad")
-#define wmb()           membar("#StoreStore")
 #define read_barrier_depends()          do { } while(0)
 #define set_mb(__var, __value) \
-        do { __var = __value; membar("#StoreLoad | #StoreStore"); } while(0)
+        do { __var = __value; membar_storeload_storestore(); } while(0)
 #define set_wmb(__var, __value) \
-        do { __var = __value; membar("#StoreStore"); } while(0)
+        do { __var = __value; wmb(); } while(0)
 
 #ifdef CONFIG_SMP
 #define smp_mb()        mb()