Add cmpxchg_local to asm-generic for per cpu atomic operations

[firefly-linux-kernel-4.4.55.git] / include / asm-generic / cmpxchg-local.h

diff --git a/include/asm-generic/cmpxchg-local.h b/include/asm-generic/cmpxchg-local.h
new file mode 100644 (file)
index 0000000..b2ba2fc
--- /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