1 files changed, 65 insertions, 0 deletions

diff --git a/include/asm-generic/cmpxchg-local.h b/include/asm-generic/cmpxchg-local.h
new file mode 100644
index 000000000000..b2ba2fc8829a
--- /dev/null
+++ b/include/asm-generic/cmpxchg-local.h
@@ -0,0 +1,65 @@
+#ifndef __ASM_GENERIC_CMPXCHG_LOCAL_H
+#define __ASM_GENERIC_CMPXCHG_LOCAL_H
+
+#include <linux/types.h>
+
+extern unsigned long wrong_size_cmpxchg(volatile void *ptr);
+
+/*
+ * Generic version of __cmpxchg_local (disables interrupts). Takes an unsigned
+ * long parameter, supporting various types of architectures.
+ */
+static inline unsigned long __cmpxchg_local_generic(volatile void *ptr,
+                unsigned long old, unsigned long new, int size)
+{
+        unsigned long flags, prev;
+
+        /*
+         * Sanity checking, compile-time.
+         */
+        if (size == 8 && sizeof(unsigned long) != 8)
+                wrong_size_cmpxchg(ptr);
+
+        local_irq_save(flags);
+        switch (size) {
+        case 1: prev = *(u8 *)ptr;
+                if (prev == old)
+                        *(u8 *)ptr = (u8)new;
+                break;
+        case 2: prev = *(u16 *)ptr;
+                if (prev == old)
+                        *(u16 *)ptr = (u16)new;
+                break;
+        case 4: prev = *(u32 *)ptr;
+                if (prev == old)
+                        *(u32 *)ptr = (u32)new;
+                break;
+        case 8: prev = *(u64 *)ptr;
+                if (prev == old)
+                        *(u64 *)ptr = (u64)new;
+                break;
+        default:
+                wrong_size_cmpxchg(ptr);
+        }
+        local_irq_restore(flags);
+        return prev;
+}
+
+/*
+ * Generic version of __cmpxchg64_local. Takes an u64 parameter.
+ */
+static inline u64 __cmpxchg64_local_generic(volatile void *ptr,
+                u64 old, u64 new)
+{
+        u64 prev;
+        unsigned long flags;
+
+        local_irq_save(flags);
+        prev = *(u64 *)ptr;
+        if (prev == old)
+                *(u64 *)ptr = new;
+        local_irq_restore(flags);
+        return prev;
+}
+
+#endif