Add cmpxchg_local to xtensa

Use the architecture specific __cmpxchg_u32 for 32 bits cmpxchg)_local. Else,
use the new generic cmpxchg_local (disables interrupt).

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Chris Zankel <chris@zankel.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 22 insertions, 0 deletions

diff --git a/include/asm-xtensa/system.h b/include/asm-xtensa/system.h
index ddc970847ae..e0cb9116d8a 100644
--- a/include/asm-xtensa/system.h
+++ b/include/asm-xtensa/system.h
@@ -156,8 +156,30 @@ __cmpxchg(volatile void *ptr, unsigned long old, unsigned long new, int size)
                                         (unsigned long)_n_, sizeof (*(ptr))); \
         })
 
+#include <asm-generic/cmpxchg-local.h>
 
+static inline unsigned long __cmpxchg_local(volatile void *ptr,
+                                      unsigned long old,
+                                      unsigned long new, int size)
+{
+        switch (size) {
+        case 4:
+                return __cmpxchg_u32(ptr, old, new);
+        default:
+                return __cmpxchg_local_generic(ptr, old, new, size);
+        }
 
+        return old;
+}
+
+/*
+ * cmpxchg_local and cmpxchg64_local are atomic wrt current CPU. Always make
+ * them available.
+ */
+#define cmpxchg_local(ptr, o, n)                                               \
+        ((__typeof__(*(ptr)))__cmpxchg_local_generic((ptr), (unsigned long)(o),\
+                        (unsigned long)(n), sizeof(*(ptr))))
+#define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n))
 
 /*
  * xchg_u32