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Diffstat (limited to 'arch/sparc/include/asm/cmpxchg_64.h')
-rw-r--r--arch/sparc/include/asm/cmpxchg_64.h76
1 files changed, 67 insertions, 9 deletions
diff --git a/arch/sparc/include/asm/cmpxchg_64.h b/arch/sparc/include/asm/cmpxchg_64.h
index faa2f61058c2..4028f4f1e561 100644
--- a/arch/sparc/include/asm/cmpxchg_64.h
+++ b/arch/sparc/include/asm/cmpxchg_64.h
@@ -6,6 +6,17 @@
#ifndef __ARCH_SPARC64_CMPXCHG__
#define __ARCH_SPARC64_CMPXCHG__
+static inline unsigned long
+__cmpxchg_u32(volatile int *m, int old, int new)
+{
+ __asm__ __volatile__("cas [%2], %3, %0"
+ : "=&r" (new)
+ : "0" (new), "r" (m), "r" (old)
+ : "memory");
+
+ return new;
+}
+
static inline unsigned long xchg32(__volatile__ unsigned int *m, unsigned int val)
{
unsigned long tmp1, tmp2;
@@ -44,10 +55,38 @@ static inline unsigned long xchg64(__volatile__ unsigned long *m, unsigned long
void __xchg_called_with_bad_pointer(void);
+/*
+ * Use 4 byte cas instruction to achieve 2 byte xchg. Main logic
+ * here is to get the bit shift of the byte we are interested in.
+ * The XOR is handy for reversing the bits for big-endian byte order.
+ */
+static inline unsigned long
+xchg16(__volatile__ unsigned short *m, unsigned short val)
+{
+ unsigned long maddr = (unsigned long)m;
+ int bit_shift = (((unsigned long)m & 2) ^ 2) << 3;
+ unsigned int mask = 0xffff << bit_shift;
+ unsigned int *ptr = (unsigned int *) (maddr & ~2);
+ unsigned int old32, new32, load32;
+
+ /* Read the old value */
+ load32 = *ptr;
+
+ do {
+ old32 = load32;
+ new32 = (load32 & (~mask)) | val << bit_shift;
+ load32 = __cmpxchg_u32(ptr, old32, new32);
+ } while (load32 != old32);
+
+ return (load32 & mask) >> bit_shift;
+}
+
static inline unsigned long __xchg(unsigned long x, __volatile__ void * ptr,
int size)
{
switch (size) {
+ case 2:
+ return xchg16(ptr, x);
case 4:
return xchg32(ptr, x);
case 8:
@@ -65,10 +104,11 @@ static inline unsigned long __xchg(unsigned long x, __volatile__ void * ptr,
#include <asm-generic/cmpxchg-local.h>
+
static inline unsigned long
-__cmpxchg_u32(volatile int *m, int old, int new)
+__cmpxchg_u64(volatile long *m, unsigned long old, unsigned long new)
{
- __asm__ __volatile__("cas [%2], %3, %0"
+ __asm__ __volatile__("casx [%2], %3, %0"
: "=&r" (new)
: "0" (new), "r" (m), "r" (old)
: "memory");
@@ -76,15 +116,31 @@ __cmpxchg_u32(volatile int *m, int old, int new)
return new;
}
+/*
+ * Use 4 byte cas instruction to achieve 1 byte cmpxchg. Main logic
+ * here is to get the bit shift of the byte we are interested in.
+ * The XOR is handy for reversing the bits for big-endian byte order
+ */
static inline unsigned long
-__cmpxchg_u64(volatile long *m, unsigned long old, unsigned long new)
+__cmpxchg_u8(volatile unsigned char *m, unsigned char old, unsigned char new)
{
- __asm__ __volatile__("casx [%2], %3, %0"
- : "=&r" (new)
- : "0" (new), "r" (m), "r" (old)
- : "memory");
-
- return new;
+ unsigned long maddr = (unsigned long)m;
+ int bit_shift = (((unsigned long)m & 3) ^ 3) << 3;
+ unsigned int mask = 0xff << bit_shift;
+ unsigned int *ptr = (unsigned int *) (maddr & ~3);
+ unsigned int old32, new32, load;
+ unsigned int load32 = *ptr;
+
+ do {
+ new32 = (load32 & ~mask) | (new << bit_shift);
+ old32 = (load32 & ~mask) | (old << bit_shift);
+ load32 = __cmpxchg_u32(ptr, old32, new32);
+ if (load32 == old32)
+ return old;
+ load = (load32 & mask) >> bit_shift;
+ } while (load == old);
+
+ return load;
}
/* This function doesn't exist, so you'll get a linker error
@@ -95,6 +151,8 @@ static inline unsigned long
__cmpxchg(volatile void *ptr, unsigned long old, unsigned long new, int size)
{
switch (size) {
+ case 1:
+ return __cmpxchg_u8(ptr, old, new);
case 4:
return __cmpxchg_u32(ptr, old, new);
case 8: