Add cmpxchg_local to sparc64

Use cmpxchg_u32 and cmpxchg_u64 for cmpxchg_local and cmpxchg64_local. For other
type sizes, use the new generic cmpxchg_local (disables interrupt).

Change:
Since the header depends on local_irqsave/local_irqrestore, it must be
included after their declaration.

Actually, being below the
#include <linux/irqflags.h> should be enough, and on sparc64 it is
included at the beginning of system.h.

So it makes sense to move it up for sparc64.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 29 insertions, 0 deletions

diff --git a/include/asm-sparc64/system.h b/include/asm-sparc64/system.h
index 99a669c190c7..1faefa6d3708 100644
--- a/include/asm-sparc64/system.h
+++ b/include/asm-sparc64/system.h
@@ -8,6 +8,7 @@
 #ifndef __ASSEMBLY__
 
 #include <linux/irqflags.h>
+#include <asm-generic/cmpxchg-local.h>
 
 /*
  * Sparc (general) CPU types
@@ -315,6 +316,34 @@ __cmpxchg(volatile void *ptr, unsigned long old, unsigned long new, int size)
                                     (unsigned long)_n_, sizeof(*(ptr))); \
   })
 
+/*
+ * cmpxchg_local and cmpxchg64_local are atomic wrt current CPU. Always make
+ * them available.
+ */
+
+static inline unsigned long __cmpxchg_local(volatile void *ptr,
+                                      unsigned long old,
+                                      unsigned long new, int size)
+{
+        switch (size) {
+        case 4:
+        case 8: return __cmpxchg(ptr, old, new, size);
+        default:
+                return __cmpxchg_local_generic(ptr, old, new, size);
+        }
+
+        return old;
+}
+
+#define cmpxchg_local(ptr, o, n)                                        \
+        ((__typeof__(*(ptr)))__cmpxchg_local((ptr), (unsigned long)(o), \
+                        (unsigned long)(n), sizeof(*(ptr))))
+#define cmpxchg64_local(ptr, o, n)                                      \
+  ({                                                                    \
+        BUILD_BUG_ON(sizeof(*(ptr)) != 8);                              \
+        cmpxchg_local((ptr), (o), (n));                                 \
+  })
+
 #endif /* !(__ASSEMBLY__) */
 
 #define arch_align_stack(x) (x)