[MIPS] Type proof reimplementation of cmpxchg.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/include/asm-mips/cmpxchg.h b/include/asm-mips/cmpxchg.h
new file mode 100644
index 0000000..c5b4708
--- /dev/null
+++ b/include/asm-mips/cmpxchg.h
@@ -0,0 +1,107 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 2003, 06, 07 by Ralf Baechle (ralf@linux-mips.org)
+ */
+#ifndef __ASM_CMPXCHG_H
+#define __ASM_CMPXCHG_H
+
+#include <linux/irqflags.h>
+
+#define __HAVE_ARCH_CMPXCHG 1
+
+#define __cmpxchg_asm(ld, st, m, old, new) \
+({ \
+ __typeof(*(m)) __ret; \
+ \
+ if (cpu_has_llsc && R10000_LLSC_WAR) { \
+ __asm__ __volatile__( \
+ " .set push \n" \
+ " .set noat \n" \
+ " .set mips3 \n" \
+ "1: " ld " %0, %2 # __cmpxchg_asm \n" \
+ " bne %0, %z3, 2f \n" \
+ " .set mips0 \n" \
+ " move $1, %z4 \n" \
+ " .set mips3 \n" \
+ " " st " $1, %1 \n" \
+ " beqzl $1, 1b \n" \
+ "2: \n" \
+ " .set pop \n" \
+ : "=&r" (__ret), "=R" (*m) \
+ : "R" (*m), "Jr" (old), "Jr" (new) \
+ : "memory"); \
+ } else if (cpu_has_llsc) { \
+ __asm__ __volatile__( \
+ " .set push \n" \
+ " .set noat \n" \
+ " .set mips3 \n" \
+ "1: " ld " %0, %2 # __cmpxchg_asm \n" \
+ " bne %0, %z3, 2f \n" \
+ " .set mips0 \n" \
+ " move $1, %z4 \n" \
+ " .set mips3 \n" \
+ " " st " $1, %1 \n" \
+ " beqz $1, 3f \n" \
+ "2: \n" \
+ " .subsection 2 \n" \
+ "3: b 1b \n" \
+ " .previous \n" \
+ " .set pop \n" \
+ : "=&r" (__ret), "=R" (*m) \
+ : "R" (*m), "Jr" (old), "Jr" (new) \
+ : "memory"); \
+ } else { \
+ unsigned long __flags; \
+ \
+ raw_local_irq_save(__flags); \
+ __ret = *m; \
+ if (__ret == old) \
+ *m = new; \
+ raw_local_irq_restore(__flags); \
+ } \
+ \
+ __ret; \
+})
+
+/*
+ * This function doesn't exist, so you'll get a linker error
+ * if something tries to do an invalid cmpxchg().
+ */
+extern void __cmpxchg_called_with_bad_pointer(void);
+
+#define __cmpxchg(ptr,old,new,barrier) \
+({ \
+ __typeof__(ptr) __ptr = (ptr); \
+ __typeof__(*(ptr)) __old = (old); \
+ __typeof__(*(ptr)) __new = (new); \
+ __typeof__(*(ptr)) __res = 0; \
+ \
+ barrier; \
+ \
+ switch (sizeof(*(__ptr))) { \
+ case 4: \
+ __res = __cmpxchg_asm("ll", "sc", __ptr, __old, __new); \
+ break; \
+ case 8: \
+ if (sizeof(long) == 8) { \
+ __res = __cmpxchg_asm("lld", "scd", __ptr, \
+ __old, __new); \
+ break; \
+ } \
+ default: \
+ __cmpxchg_called_with_bad_pointer(); \
+ break; \
+ } \
+ \
+ barrier; \
+ \
+ __res; \
+})
+
+#define cmpxchg(ptr, old, new) __cmpxchg(ptr, old, new, smp_llsc_mb())
+#define cmpxchg_local(ptr, old, new) __cmpxchg(ptr, old, new,)
+
+#endif /* __ASM_CMPXCHG_H */