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Diffstat (limited to 'arch/s390/include/asm/cmpxchg.h')
-rw-r--r--arch/s390/include/asm/cmpxchg.h281
1 files changed, 244 insertions, 37 deletions
diff --git a/arch/s390/include/asm/cmpxchg.h b/arch/s390/include/asm/cmpxchg.h
index af99c1f66f12..a9e2006033b7 100644
--- a/arch/s390/include/asm/cmpxchg.h
+++ b/arch/s390/include/asm/cmpxchg.h
@@ -11,56 +11,263 @@
#include <linux/mmdebug.h>
#include <linux/types.h>
#include <linux/bug.h>
+#include <asm/asm.h>
-#define cmpxchg(ptr, o, n) \
+void __cmpxchg_called_with_bad_pointer(void);
+
+static __always_inline u32 __cs_asm(u64 ptr, u32 old, u32 new)
+{
+ asm volatile(
+ " cs %[old],%[new],%[ptr]\n"
+ : [old] "+d" (old), [ptr] "+Q" (*(u32 *)ptr)
+ : [new] "d" (new)
+ : "memory", "cc");
+ return old;
+}
+
+static __always_inline u64 __csg_asm(u64 ptr, u64 old, u64 new)
+{
+ asm volatile(
+ " csg %[old],%[new],%[ptr]\n"
+ : [old] "+d" (old), [ptr] "+QS" (*(u64 *)ptr)
+ : [new] "d" (new)
+ : "memory", "cc");
+ return old;
+}
+
+static inline u8 __arch_cmpxchg1(u64 ptr, u8 old, u8 new)
+{
+ union {
+ u8 b[4];
+ u32 w;
+ } old32, new32;
+ u32 prev;
+ int i;
+
+ i = ptr & 3;
+ ptr &= ~0x3;
+ prev = READ_ONCE(*(u32 *)ptr);
+ do {
+ old32.w = prev;
+ if (old32.b[i] != old)
+ return old32.b[i];
+ new32.w = old32.w;
+ new32.b[i] = new;
+ prev = __cs_asm(ptr, old32.w, new32.w);
+ } while (prev != old32.w);
+ return old;
+}
+
+static inline u16 __arch_cmpxchg2(u64 ptr, u16 old, u16 new)
+{
+ union {
+ u16 b[2];
+ u32 w;
+ } old32, new32;
+ u32 prev;
+ int i;
+
+ i = (ptr & 3) >> 1;
+ ptr &= ~0x3;
+ prev = READ_ONCE(*(u32 *)ptr);
+ do {
+ old32.w = prev;
+ if (old32.b[i] != old)
+ return old32.b[i];
+ new32.w = old32.w;
+ new32.b[i] = new;
+ prev = __cs_asm(ptr, old32.w, new32.w);
+ } while (prev != old32.w);
+ return old;
+}
+
+static __always_inline u64 __arch_cmpxchg(u64 ptr, u64 old, u64 new, int size)
+{
+ switch (size) {
+ case 1: return __arch_cmpxchg1(ptr, old & 0xff, new & 0xff);
+ case 2: return __arch_cmpxchg2(ptr, old & 0xffff, new & 0xffff);
+ case 4: return __cs_asm(ptr, old & 0xffffffff, new & 0xffffffff);
+ case 8: return __csg_asm(ptr, old, new);
+ default: __cmpxchg_called_with_bad_pointer();
+ }
+ return old;
+}
+
+#define arch_cmpxchg(ptr, o, n) \
({ \
- __typeof__(*(ptr)) __o = (o); \
- __typeof__(*(ptr)) __n = (n); \
- (__typeof__(*(ptr))) __sync_val_compare_and_swap((ptr),__o,__n);\
+ (__typeof__(*(ptr)))__arch_cmpxchg((unsigned long)(ptr), \
+ (unsigned long)(o), \
+ (unsigned long)(n), \
+ sizeof(*(ptr))); \
})
-#define cmpxchg64 cmpxchg
-#define cmpxchg_local cmpxchg
-#define cmpxchg64_local cmpxchg
+#define arch_cmpxchg64 arch_cmpxchg
+#define arch_cmpxchg_local arch_cmpxchg
+#define arch_cmpxchg64_local arch_cmpxchg
+
+#ifdef __HAVE_ASM_FLAG_OUTPUTS__
-#define xchg(ptr, x) \
+#define arch_try_cmpxchg(ptr, oldp, new) \
({ \
- __typeof__(ptr) __ptr = (ptr); \
- __typeof__(*(ptr)) __old; \
- do { \
- __old = *__ptr; \
- } while (!__sync_bool_compare_and_swap(__ptr, __old, x)); \
- __old; \
+ __typeof__(ptr) __oldp = (__typeof__(ptr))(oldp); \
+ __typeof__(*(ptr)) __old = *__oldp; \
+ __typeof__(*(ptr)) __new = (new); \
+ __typeof__(*(ptr)) __prev; \
+ int __cc; \
+ \
+ switch (sizeof(*(ptr))) { \
+ case 1: \
+ case 2: { \
+ __prev = arch_cmpxchg((ptr), (__old), (__new)); \
+ __cc = (__prev != __old); \
+ if (unlikely(__cc)) \
+ *__oldp = __prev; \
+ break; \
+ } \
+ case 4: { \
+ asm volatile( \
+ " cs %[__old],%[__new],%[__ptr]\n" \
+ : [__old] "+d" (*__oldp), \
+ [__ptr] "+Q" (*(ptr)), \
+ "=@cc" (__cc) \
+ : [__new] "d" (__new) \
+ : "memory"); \
+ break; \
+ } \
+ case 8: { \
+ asm volatile( \
+ " csg %[__old],%[__new],%[__ptr]\n" \
+ : [__old] "+d" (*__oldp), \
+ [__ptr] "+QS" (*(ptr)), \
+ "=@cc" (__cc) \
+ : [__new] "d" (__new) \
+ : "memory"); \
+ break; \
+ } \
+ default: \
+ __cmpxchg_called_with_bad_pointer(); \
+ } \
+ likely(__cc == 0); \
})
-#define __cmpxchg_double(p1, p2, o1, o2, n1, n2) \
+#else /* __HAVE_ASM_FLAG_OUTPUTS__ */
+
+#define arch_try_cmpxchg(ptr, oldp, new) \
({ \
- register __typeof__(*(p1)) __old1 asm("2") = (o1); \
- register __typeof__(*(p2)) __old2 asm("3") = (o2); \
- register __typeof__(*(p1)) __new1 asm("4") = (n1); \
- register __typeof__(*(p2)) __new2 asm("5") = (n2); \
- int cc; \
- asm volatile( \
- " cdsg %[old],%[new],%[ptr]\n" \
- " ipm %[cc]\n" \
- " srl %[cc],28" \
- : [cc] "=d" (cc), [old] "+d" (__old1), "+d" (__old2) \
- : [new] "d" (__new1), "d" (__new2), \
- [ptr] "Q" (*(p1)), "Q" (*(p2)) \
- : "memory", "cc"); \
- !cc; \
+ __typeof__((ptr)) __oldp = (__typeof__(ptr))(oldp); \
+ __typeof__(*(ptr)) __old = *__oldp; \
+ __typeof__(*(ptr)) __new = (new); \
+ __typeof__(*(ptr)) __prev; \
+ \
+ __prev = arch_cmpxchg((ptr), (__old), (__new)); \
+ if (unlikely(__prev != __old)) \
+ *__oldp = __prev; \
+ likely(__prev == __old); \
})
-#define cmpxchg_double(p1, p2, o1, o2, n1, n2) \
+#endif /* __HAVE_ASM_FLAG_OUTPUTS__ */
+
+#define arch_try_cmpxchg64 arch_try_cmpxchg
+#define arch_try_cmpxchg_local arch_try_cmpxchg
+#define arch_try_cmpxchg64_local arch_try_cmpxchg
+
+void __xchg_called_with_bad_pointer(void);
+
+static inline u8 __arch_xchg1(u64 ptr, u8 x)
+{
+ int shift = (3 ^ (ptr & 3)) << 3;
+ u32 mask, old, new;
+
+ ptr &= ~0x3;
+ mask = ~(0xff << shift);
+ old = READ_ONCE(*(u32 *)ptr);
+ do {
+ new = old & mask;
+ new |= x << shift;
+ } while (!arch_try_cmpxchg((u32 *)ptr, &old, new));
+ return old >> shift;
+}
+
+static inline u16 __arch_xchg2(u64 ptr, u16 x)
+{
+ int shift = (2 ^ (ptr & 2)) << 3;
+ u32 mask, old, new;
+
+ ptr &= ~0x3;
+ mask = ~(0xffff << shift);
+ old = READ_ONCE(*(u32 *)ptr);
+ do {
+ new = old & mask;
+ new |= x << shift;
+ } while (!arch_try_cmpxchg((u32 *)ptr, &old, new));
+ return old >> shift;
+}
+
+static __always_inline u64 __arch_xchg(u64 ptr, u64 x, int size)
+{
+ switch (size) {
+ case 1:
+ return __arch_xchg1(ptr, x & 0xff);
+ case 2:
+ return __arch_xchg2(ptr, x & 0xffff);
+ case 4: {
+ u32 old = READ_ONCE(*(u32 *)ptr);
+
+ do {
+ } while (!arch_try_cmpxchg((u32 *)ptr, &old, x & 0xffffffff));
+ return old;
+ }
+ case 8: {
+ u64 old = READ_ONCE(*(u64 *)ptr);
+
+ do {
+ } while (!arch_try_cmpxchg((u64 *)ptr, &old, x));
+ return old;
+ }
+ }
+ __xchg_called_with_bad_pointer();
+ return x;
+}
+
+#define arch_xchg(ptr, x) \
({ \
- __typeof__(p1) __p1 = (p1); \
- __typeof__(p2) __p2 = (p2); \
- BUILD_BUG_ON(sizeof(*(p1)) != sizeof(long)); \
- BUILD_BUG_ON(sizeof(*(p2)) != sizeof(long)); \
- VM_BUG_ON((unsigned long)((__p1) + 1) != (unsigned long)(__p2));\
- __cmpxchg_double(__p1, __p2, o1, o2, n1, n2); \
+ (__typeof__(*(ptr)))__arch_xchg((unsigned long)(ptr), \
+ (unsigned long)(x), \
+ sizeof(*(ptr))); \
})
-#define system_has_cmpxchg_double() 1
+#define system_has_cmpxchg128() 1
+
+static __always_inline u128 arch_cmpxchg128(volatile u128 *ptr, u128 old, u128 new)
+{
+ asm volatile(
+ " cdsg %[old],%[new],%[ptr]\n"
+ : [old] "+d" (old), [ptr] "+QS" (*ptr)
+ : [new] "d" (new)
+ : "memory", "cc");
+ return old;
+}
+
+#define arch_cmpxchg128 arch_cmpxchg128
+#define arch_cmpxchg128_local arch_cmpxchg128
+
+#ifdef __HAVE_ASM_FLAG_OUTPUTS__
+
+static __always_inline bool arch_try_cmpxchg128(volatile u128 *ptr, u128 *oldp, u128 new)
+{
+ int cc;
+
+ asm volatile(
+ " cdsg %[old],%[new],%[ptr]\n"
+ : [old] "+d" (*oldp), [ptr] "+QS" (*ptr), "=@cc" (cc)
+ : [new] "d" (new)
+ : "memory");
+ return likely(cc == 0);
+}
+
+#define arch_try_cmpxchg128 arch_try_cmpxchg128
+#define arch_try_cmpxchg128_local arch_try_cmpxchg128
+
+#endif /* __HAVE_ASM_FLAG_OUTPUTS__ */
#endif /* __ASM_CMPXCHG_H */
generated by cgit (git 2.34.1) at 2025-07-31 22:46:18 +0000