[SPARC]: Try to start getting SMP back into shape.

Todo items:
 - IRQ_INPROGRESS flag - use sparc64 irq buckets, or generic irq_desc?
 - sun4d
 - re-indent large chunks of sun4m_smp.c
 - some places assume sequential cpu numbering (i.e. 0,1 instead of 0,2)

Last I checked (with 2.6.14), random programs segfault with dual
HyperSPARC.  And with SuperSPARC II's, it seems stable but will
eventually die from a write lock error (wrong lock owner or something).

I haven't tried the HyperSPARC + highmem combination recently, so that
may still be a problem.

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

1 files changed, 22 insertions, 3 deletions

diff --git a/include/asm-sparc/spinlock.h b/include/asm-sparc/spinlock.h
index e344c98a6f5f..3350c90c7869 100644
--- a/include/asm-sparc/spinlock.h
+++ b/include/asm-sparc/spinlock.h
@@ -94,7 +94,7 @@ static inline void __read_lock(raw_rwlock_t *rw)
 #define __raw_read_lock(lock) \
 do {    unsigned long flags; \
         local_irq_save(flags); \
-        __raw_read_lock(lock); \
+        __read_lock(lock); \
         local_irq_restore(flags); \
 } while(0)
 
@@ -114,11 +114,11 @@ static inline void __read_unlock(raw_rwlock_t *rw)
 #define __raw_read_unlock(lock) \
 do {    unsigned long flags; \
         local_irq_save(flags); \
-        __raw_read_unlock(lock); \
+        __read_unlock(lock); \
         local_irq_restore(flags); \
 } while(0)
 
-extern __inline__ void __raw_write_lock(raw_rwlock_t *rw)
+static inline void __raw_write_lock(raw_rwlock_t *rw)
 {
         register raw_rwlock_t *lp asm("g1");
         lp = rw;
@@ -131,9 +131,28 @@ extern __inline__ void __raw_write_lock(raw_rwlock_t *rw)
         : "g2", "g4", "memory", "cc");
 }
 
+static inline int __raw_write_trylock(raw_rwlock_t *rw)
+{
+        unsigned int val;
+
+        __asm__ __volatile__("ldstub [%1 + 3], %0"
+                             : "=r" (val)
+                             : "r" (&rw->lock)
+                             : "memory");
+
+        if (val == 0) {
+                val = rw->lock & ~0xff;
+                if (val)
+                        ((volatile u8*)&rw->lock)[3] = 0;
+        }
+
+        return (val == 0);
+}
+
 #define __raw_write_unlock(rw)  do { (rw)->lock = 0; } while(0)
 
 #define __raw_spin_lock_flags(lock, flags) __raw_spin_lock(lock)
+#define __raw_read_trylock(lock) generic__raw_read_trylock(lock)
 
 #endif /* !(__ASSEMBLY__) */