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-rw-r--r--arch/powerpc/include/asm/cmpxchg.h531
1 files changed, 531 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/cmpxchg.h b/arch/powerpc/include/asm/cmpxchg.h
new file mode 100644
index 000000000..05f246c0e
--- /dev/null
+++ b/arch/powerpc/include/asm/cmpxchg.h
@@ -0,0 +1,531 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_POWERPC_CMPXCHG_H_
+#define _ASM_POWERPC_CMPXCHG_H_
+
+#ifdef __KERNEL__
+#include <linux/compiler.h>
+#include <asm/synch.h>
+#include <linux/bug.h>
+
+#ifdef __BIG_ENDIAN
+#define BITOFF_CAL(size, off) ((sizeof(u32) - size - off) * BITS_PER_BYTE)
+#else
+#define BITOFF_CAL(size, off) (off * BITS_PER_BYTE)
+#endif
+
+#define XCHG_GEN(type, sfx, cl) \
+static inline u32 __xchg_##type##sfx(volatile void *p, u32 val) \
+{ \
+ unsigned int prev, prev_mask, tmp, bitoff, off; \
+ \
+ off = (unsigned long)p % sizeof(u32); \
+ bitoff = BITOFF_CAL(sizeof(type), off); \
+ p -= off; \
+ val <<= bitoff; \
+ prev_mask = (u32)(type)-1 << bitoff; \
+ \
+ __asm__ __volatile__( \
+"1: lwarx %0,0,%3\n" \
+" andc %1,%0,%5\n" \
+" or %1,%1,%4\n" \
+" stwcx. %1,0,%3\n" \
+" bne- 1b\n" \
+ : "=&r" (prev), "=&r" (tmp), "+m" (*(u32*)p) \
+ : "r" (p), "r" (val), "r" (prev_mask) \
+ : "cc", cl); \
+ \
+ return prev >> bitoff; \
+}
+
+#define CMPXCHG_GEN(type, sfx, br, br2, cl) \
+static inline \
+u32 __cmpxchg_##type##sfx(volatile void *p, u32 old, u32 new) \
+{ \
+ unsigned int prev, prev_mask, tmp, bitoff, off; \
+ \
+ off = (unsigned long)p % sizeof(u32); \
+ bitoff = BITOFF_CAL(sizeof(type), off); \
+ p -= off; \
+ old <<= bitoff; \
+ new <<= bitoff; \
+ prev_mask = (u32)(type)-1 << bitoff; \
+ \
+ __asm__ __volatile__( \
+ br \
+"1: lwarx %0,0,%3\n" \
+" and %1,%0,%6\n" \
+" cmpw 0,%1,%4\n" \
+" bne- 2f\n" \
+" andc %1,%0,%6\n" \
+" or %1,%1,%5\n" \
+" stwcx. %1,0,%3\n" \
+" bne- 1b\n" \
+ br2 \
+ "\n" \
+"2:" \
+ : "=&r" (prev), "=&r" (tmp), "+m" (*(u32*)p) \
+ : "r" (p), "r" (old), "r" (new), "r" (prev_mask) \
+ : "cc", cl); \
+ \
+ return prev >> bitoff; \
+}
+
+/*
+ * Atomic exchange
+ *
+ * Changes the memory location '*p' to be val and returns
+ * the previous value stored there.
+ */
+
+XCHG_GEN(u8, _local, "memory");
+XCHG_GEN(u8, _relaxed, "cc");
+XCHG_GEN(u16, _local, "memory");
+XCHG_GEN(u16, _relaxed, "cc");
+
+static __always_inline unsigned long
+__xchg_u32_local(volatile void *p, unsigned long val)
+{
+ unsigned long prev;
+
+ __asm__ __volatile__(
+"1: lwarx %0,0,%2 \n"
+" stwcx. %3,0,%2 \n\
+ bne- 1b"
+ : "=&r" (prev), "+m" (*(volatile unsigned int *)p)
+ : "r" (p), "r" (val)
+ : "cc", "memory");
+
+ return prev;
+}
+
+static __always_inline unsigned long
+__xchg_u32_relaxed(u32 *p, unsigned long val)
+{
+ unsigned long prev;
+
+ __asm__ __volatile__(
+"1: lwarx %0,0,%2\n"
+" stwcx. %3,0,%2\n"
+" bne- 1b"
+ : "=&r" (prev), "+m" (*p)
+ : "r" (p), "r" (val)
+ : "cc");
+
+ return prev;
+}
+
+#ifdef CONFIG_PPC64
+static __always_inline unsigned long
+__xchg_u64_local(volatile void *p, unsigned long val)
+{
+ unsigned long prev;
+
+ __asm__ __volatile__(
+"1: ldarx %0,0,%2 \n"
+" stdcx. %3,0,%2 \n\
+ bne- 1b"
+ : "=&r" (prev), "+m" (*(volatile unsigned long *)p)
+ : "r" (p), "r" (val)
+ : "cc", "memory");
+
+ return prev;
+}
+
+static __always_inline unsigned long
+__xchg_u64_relaxed(u64 *p, unsigned long val)
+{
+ unsigned long prev;
+
+ __asm__ __volatile__(
+"1: ldarx %0,0,%2\n"
+" stdcx. %3,0,%2\n"
+" bne- 1b"
+ : "=&r" (prev), "+m" (*p)
+ : "r" (p), "r" (val)
+ : "cc");
+
+ return prev;
+}
+#endif
+
+static __always_inline unsigned long
+__xchg_local(void *ptr, unsigned long x, unsigned int size)
+{
+ switch (size) {
+ case 1:
+ return __xchg_u8_local(ptr, x);
+ case 2:
+ return __xchg_u16_local(ptr, x);
+ case 4:
+ return __xchg_u32_local(ptr, x);
+#ifdef CONFIG_PPC64
+ case 8:
+ return __xchg_u64_local(ptr, x);
+#endif
+ }
+ BUILD_BUG_ON_MSG(1, "Unsupported size for __xchg");
+ return x;
+}
+
+static __always_inline unsigned long
+__xchg_relaxed(void *ptr, unsigned long x, unsigned int size)
+{
+ switch (size) {
+ case 1:
+ return __xchg_u8_relaxed(ptr, x);
+ case 2:
+ return __xchg_u16_relaxed(ptr, x);
+ case 4:
+ return __xchg_u32_relaxed(ptr, x);
+#ifdef CONFIG_PPC64
+ case 8:
+ return __xchg_u64_relaxed(ptr, x);
+#endif
+ }
+ BUILD_BUG_ON_MSG(1, "Unsupported size for __xchg_local");
+ return x;
+}
+#define arch_xchg_local(ptr,x) \
+ ({ \
+ __typeof__(*(ptr)) _x_ = (x); \
+ (__typeof__(*(ptr))) __xchg_local((ptr), \
+ (unsigned long)_x_, sizeof(*(ptr))); \
+ })
+
+#define arch_xchg_relaxed(ptr, x) \
+({ \
+ __typeof__(*(ptr)) _x_ = (x); \
+ (__typeof__(*(ptr))) __xchg_relaxed((ptr), \
+ (unsigned long)_x_, sizeof(*(ptr))); \
+})
+/*
+ * Compare and exchange - if *p == old, set it to new,
+ * and return the old value of *p.
+ */
+
+CMPXCHG_GEN(u8, , PPC_ATOMIC_ENTRY_BARRIER, PPC_ATOMIC_EXIT_BARRIER, "memory");
+CMPXCHG_GEN(u8, _local, , , "memory");
+CMPXCHG_GEN(u8, _acquire, , PPC_ACQUIRE_BARRIER, "memory");
+CMPXCHG_GEN(u8, _relaxed, , , "cc");
+CMPXCHG_GEN(u16, , PPC_ATOMIC_ENTRY_BARRIER, PPC_ATOMIC_EXIT_BARRIER, "memory");
+CMPXCHG_GEN(u16, _local, , , "memory");
+CMPXCHG_GEN(u16, _acquire, , PPC_ACQUIRE_BARRIER, "memory");
+CMPXCHG_GEN(u16, _relaxed, , , "cc");
+
+static __always_inline unsigned long
+__cmpxchg_u32(volatile unsigned int *p, unsigned long old, unsigned long new)
+{
+ unsigned int prev;
+
+ __asm__ __volatile__ (
+ PPC_ATOMIC_ENTRY_BARRIER
+"1: lwarx %0,0,%2 # __cmpxchg_u32\n\
+ cmpw 0,%0,%3\n\
+ bne- 2f\n"
+" stwcx. %4,0,%2\n\
+ bne- 1b"
+ PPC_ATOMIC_EXIT_BARRIER
+ "\n\
+2:"
+ : "=&r" (prev), "+m" (*p)
+ : "r" (p), "r" (old), "r" (new)
+ : "cc", "memory");
+
+ return prev;
+}
+
+static __always_inline unsigned long
+__cmpxchg_u32_local(volatile unsigned int *p, unsigned long old,
+ unsigned long new)
+{
+ unsigned int prev;
+
+ __asm__ __volatile__ (
+"1: lwarx %0,0,%2 # __cmpxchg_u32\n\
+ cmpw 0,%0,%3\n\
+ bne- 2f\n"
+" stwcx. %4,0,%2\n\
+ bne- 1b"
+ "\n\
+2:"
+ : "=&r" (prev), "+m" (*p)
+ : "r" (p), "r" (old), "r" (new)
+ : "cc", "memory");
+
+ return prev;
+}
+
+static __always_inline unsigned long
+__cmpxchg_u32_relaxed(u32 *p, unsigned long old, unsigned long new)
+{
+ unsigned long prev;
+
+ __asm__ __volatile__ (
+"1: lwarx %0,0,%2 # __cmpxchg_u32_relaxed\n"
+" cmpw 0,%0,%3\n"
+" bne- 2f\n"
+" stwcx. %4,0,%2\n"
+" bne- 1b\n"
+"2:"
+ : "=&r" (prev), "+m" (*p)
+ : "r" (p), "r" (old), "r" (new)
+ : "cc");
+
+ return prev;
+}
+
+/*
+ * cmpxchg family don't have order guarantee if cmp part fails, therefore we
+ * can avoid superfluous barriers if we use assembly code to implement
+ * cmpxchg() and cmpxchg_acquire(), however we don't do the similar for
+ * cmpxchg_release() because that will result in putting a barrier in the
+ * middle of a ll/sc loop, which is probably a bad idea. For example, this
+ * might cause the conditional store more likely to fail.
+ */
+static __always_inline unsigned long
+__cmpxchg_u32_acquire(u32 *p, unsigned long old, unsigned long new)
+{
+ unsigned long prev;
+
+ __asm__ __volatile__ (
+"1: lwarx %0,0,%2 # __cmpxchg_u32_acquire\n"
+" cmpw 0,%0,%3\n"
+" bne- 2f\n"
+" stwcx. %4,0,%2\n"
+" bne- 1b\n"
+ PPC_ACQUIRE_BARRIER
+ "\n"
+"2:"
+ : "=&r" (prev), "+m" (*p)
+ : "r" (p), "r" (old), "r" (new)
+ : "cc", "memory");
+
+ return prev;
+}
+
+#ifdef CONFIG_PPC64
+static __always_inline unsigned long
+__cmpxchg_u64(volatile unsigned long *p, unsigned long old, unsigned long new)
+{
+ unsigned long prev;
+
+ __asm__ __volatile__ (
+ PPC_ATOMIC_ENTRY_BARRIER
+"1: ldarx %0,0,%2 # __cmpxchg_u64\n\
+ cmpd 0,%0,%3\n\
+ bne- 2f\n\
+ stdcx. %4,0,%2\n\
+ bne- 1b"
+ PPC_ATOMIC_EXIT_BARRIER
+ "\n\
+2:"
+ : "=&r" (prev), "+m" (*p)
+ : "r" (p), "r" (old), "r" (new)
+ : "cc", "memory");
+
+ return prev;
+}
+
+static __always_inline unsigned long
+__cmpxchg_u64_local(volatile unsigned long *p, unsigned long old,
+ unsigned long new)
+{
+ unsigned long prev;
+
+ __asm__ __volatile__ (
+"1: ldarx %0,0,%2 # __cmpxchg_u64\n\
+ cmpd 0,%0,%3\n\
+ bne- 2f\n\
+ stdcx. %4,0,%2\n\
+ bne- 1b"
+ "\n\
+2:"
+ : "=&r" (prev), "+m" (*p)
+ : "r" (p), "r" (old), "r" (new)
+ : "cc", "memory");
+
+ return prev;
+}
+
+static __always_inline unsigned long
+__cmpxchg_u64_relaxed(u64 *p, unsigned long old, unsigned long new)
+{
+ unsigned long prev;
+
+ __asm__ __volatile__ (
+"1: ldarx %0,0,%2 # __cmpxchg_u64_relaxed\n"
+" cmpd 0,%0,%3\n"
+" bne- 2f\n"
+" stdcx. %4,0,%2\n"
+" bne- 1b\n"
+"2:"
+ : "=&r" (prev), "+m" (*p)
+ : "r" (p), "r" (old), "r" (new)
+ : "cc");
+
+ return prev;
+}
+
+static __always_inline unsigned long
+__cmpxchg_u64_acquire(u64 *p, unsigned long old, unsigned long new)
+{
+ unsigned long prev;
+
+ __asm__ __volatile__ (
+"1: ldarx %0,0,%2 # __cmpxchg_u64_acquire\n"
+" cmpd 0,%0,%3\n"
+" bne- 2f\n"
+" stdcx. %4,0,%2\n"
+" bne- 1b\n"
+ PPC_ACQUIRE_BARRIER
+ "\n"
+"2:"
+ : "=&r" (prev), "+m" (*p)
+ : "r" (p), "r" (old), "r" (new)
+ : "cc", "memory");
+
+ return prev;
+}
+#endif
+
+static __always_inline unsigned long
+__cmpxchg(volatile void *ptr, unsigned long old, unsigned long new,
+ unsigned int size)
+{
+ switch (size) {
+ case 1:
+ return __cmpxchg_u8(ptr, old, new);
+ case 2:
+ return __cmpxchg_u16(ptr, old, new);
+ case 4:
+ return __cmpxchg_u32(ptr, old, new);
+#ifdef CONFIG_PPC64
+ case 8:
+ return __cmpxchg_u64(ptr, old, new);
+#endif
+ }
+ BUILD_BUG_ON_MSG(1, "Unsupported size for __cmpxchg");
+ return old;
+}
+
+static __always_inline unsigned long
+__cmpxchg_local(void *ptr, unsigned long old, unsigned long new,
+ unsigned int size)
+{
+ switch (size) {
+ case 1:
+ return __cmpxchg_u8_local(ptr, old, new);
+ case 2:
+ return __cmpxchg_u16_local(ptr, old, new);
+ case 4:
+ return __cmpxchg_u32_local(ptr, old, new);
+#ifdef CONFIG_PPC64
+ case 8:
+ return __cmpxchg_u64_local(ptr, old, new);
+#endif
+ }
+ BUILD_BUG_ON_MSG(1, "Unsupported size for __cmpxchg_local");
+ return old;
+}
+
+static __always_inline unsigned long
+__cmpxchg_relaxed(void *ptr, unsigned long old, unsigned long new,
+ unsigned int size)
+{
+ switch (size) {
+ case 1:
+ return __cmpxchg_u8_relaxed(ptr, old, new);
+ case 2:
+ return __cmpxchg_u16_relaxed(ptr, old, new);
+ case 4:
+ return __cmpxchg_u32_relaxed(ptr, old, new);
+#ifdef CONFIG_PPC64
+ case 8:
+ return __cmpxchg_u64_relaxed(ptr, old, new);
+#endif
+ }
+ BUILD_BUG_ON_MSG(1, "Unsupported size for __cmpxchg_relaxed");
+ return old;
+}
+
+static __always_inline unsigned long
+__cmpxchg_acquire(void *ptr, unsigned long old, unsigned long new,
+ unsigned int size)
+{
+ switch (size) {
+ case 1:
+ return __cmpxchg_u8_acquire(ptr, old, new);
+ case 2:
+ return __cmpxchg_u16_acquire(ptr, old, new);
+ case 4:
+ return __cmpxchg_u32_acquire(ptr, old, new);
+#ifdef CONFIG_PPC64
+ case 8:
+ return __cmpxchg_u64_acquire(ptr, old, new);
+#endif
+ }
+ BUILD_BUG_ON_MSG(1, "Unsupported size for __cmpxchg_acquire");
+ return old;
+}
+#define arch_cmpxchg(ptr, o, n) \
+ ({ \
+ __typeof__(*(ptr)) _o_ = (o); \
+ __typeof__(*(ptr)) _n_ = (n); \
+ (__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_, \
+ (unsigned long)_n_, sizeof(*(ptr))); \
+ })
+
+
+#define arch_cmpxchg_local(ptr, o, n) \
+ ({ \
+ __typeof__(*(ptr)) _o_ = (o); \
+ __typeof__(*(ptr)) _n_ = (n); \
+ (__typeof__(*(ptr))) __cmpxchg_local((ptr), (unsigned long)_o_, \
+ (unsigned long)_n_, sizeof(*(ptr))); \
+ })
+
+#define arch_cmpxchg_relaxed(ptr, o, n) \
+({ \
+ __typeof__(*(ptr)) _o_ = (o); \
+ __typeof__(*(ptr)) _n_ = (n); \
+ (__typeof__(*(ptr))) __cmpxchg_relaxed((ptr), \
+ (unsigned long)_o_, (unsigned long)_n_, \
+ sizeof(*(ptr))); \
+})
+
+#define arch_cmpxchg_acquire(ptr, o, n) \
+({ \
+ __typeof__(*(ptr)) _o_ = (o); \
+ __typeof__(*(ptr)) _n_ = (n); \
+ (__typeof__(*(ptr))) __cmpxchg_acquire((ptr), \
+ (unsigned long)_o_, (unsigned long)_n_, \
+ sizeof(*(ptr))); \
+})
+#ifdef CONFIG_PPC64
+#define arch_cmpxchg64(ptr, o, n) \
+ ({ \
+ BUILD_BUG_ON(sizeof(*(ptr)) != 8); \
+ arch_cmpxchg((ptr), (o), (n)); \
+ })
+#define arch_cmpxchg64_local(ptr, o, n) \
+ ({ \
+ BUILD_BUG_ON(sizeof(*(ptr)) != 8); \
+ arch_cmpxchg_local((ptr), (o), (n)); \
+ })
+#define arch_cmpxchg64_relaxed(ptr, o, n) \
+({ \
+ BUILD_BUG_ON(sizeof(*(ptr)) != 8); \
+ arch_cmpxchg_relaxed((ptr), (o), (n)); \
+})
+#define arch_cmpxchg64_acquire(ptr, o, n) \
+({ \
+ BUILD_BUG_ON(sizeof(*(ptr)) != 8); \
+ arch_cmpxchg_acquire((ptr), (o), (n)); \
+})
+#else
+#include <asm-generic/cmpxchg-local.h>
+#define arch_cmpxchg64_local(ptr, o, n) __generic_cmpxchg64_local((ptr), (o), (n))
+#endif
+
+#endif /* __KERNEL__ */
+#endif /* _ASM_POWERPC_CMPXCHG_H_ */
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