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Diffstat (limited to '')
| -rw-r--r-- | arch/loongarch/include/asm/cmpxchg.h | 219 |
1 files changed, 219 insertions, 0 deletions
diff --git a/arch/loongarch/include/asm/cmpxchg.h b/arch/loongarch/include/asm/cmpxchg.h new file mode 100644 index 000000000000..ecfa6cf79806 --- /dev/null +++ b/arch/loongarch/include/asm/cmpxchg.h @@ -0,0 +1,219 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2020-2022 Loongson Technology Corporation Limited + */ +#ifndef __ASM_CMPXCHG_H +#define __ASM_CMPXCHG_H + +#include <linux/bits.h> +#include <linux/build_bug.h> +#include <asm/barrier.h> + +#define __xchg_asm(amswap_db, m, val) \ +({ \ + __typeof(val) __ret; \ + \ + __asm__ __volatile__ ( \ + " "amswap_db" %1, %z2, %0 \n" \ + : "+ZB" (*m), "=&r" (__ret) \ + : "Jr" (val) \ + : "memory"); \ + \ + __ret; \ +}) + +static inline unsigned int __xchg_small(volatile void *ptr, unsigned int val, + unsigned int size) +{ + unsigned int shift; + u32 old32, mask, temp; + volatile u32 *ptr32; + + /* Mask value to the correct size. */ + mask = GENMASK((size * BITS_PER_BYTE) - 1, 0); + val &= mask; + + /* + * Calculate a shift & mask that correspond to the value we wish to + * exchange within the naturally aligned 4 byte integerthat includes + * it. + */ + shift = (unsigned long)ptr & 0x3; + shift *= BITS_PER_BYTE; + mask <<= shift; + + /* + * Calculate a pointer to the naturally aligned 4 byte integer that + * includes our byte of interest, and load its value. + */ + ptr32 = (volatile u32 *)((unsigned long)ptr & ~0x3); + + asm volatile ( + "1: ll.w %0, %3 \n" + " andn %1, %0, %z4 \n" + " or %1, %1, %z5 \n" + " sc.w %1, %2 \n" + " beqz %1, 1b \n" + : "=&r" (old32), "=&r" (temp), "=ZC" (*ptr32) + : "ZC" (*ptr32), "Jr" (mask), "Jr" (val << shift) + : "memory"); + + return (old32 & mask) >> shift; +} + +static __always_inline unsigned long +__xchg(volatile void *ptr, unsigned long x, int size) +{ + switch (size) { + case 1: + case 2: + return __xchg_small(ptr, x, size); + + case 4: + return __xchg_asm("amswap_db.w", (volatile u32 *)ptr, (u32)x); + + case 8: + return __xchg_asm("amswap_db.d", (volatile u64 *)ptr, (u64)x); + + default: + BUILD_BUG(); + } + + return 0; +} + +#define arch_xchg(ptr, x) \ +({ \ + __typeof__(*(ptr)) __res; \ + \ + __res = (__typeof__(*(ptr))) \ + __xchg((ptr), (unsigned long)(x), sizeof(*(ptr))); \ + \ + __res; \ +}) + +#define __cmpxchg_asm(ld, st, m, old, new) \ +({ \ + __typeof(old) __ret; \ + \ + __asm__ __volatile__( \ + "1: " ld " %0, %2 # __cmpxchg_asm \n" \ + " bne %0, %z3, 2f \n" \ + " move $t0, %z4 \n" \ + " " st " $t0, %1 \n" \ + " beqz $t0, 1b \n" \ + "2: \n" \ + __WEAK_LLSC_MB \ + : "=&r" (__ret), "=ZB"(*m) \ + : "ZB"(*m), "Jr" (old), "Jr" (new) \ + : "t0", "memory"); \ + \ + __ret; \ +}) + +static inline unsigned int __cmpxchg_small(volatile void *ptr, unsigned int old, + unsigned int new, unsigned int size) +{ + unsigned int shift; + u32 old32, mask, temp; + volatile u32 *ptr32; + + /* Mask inputs to the correct size. */ + mask = GENMASK((size * BITS_PER_BYTE) - 1, 0); + old &= mask; + new &= mask; + + /* + * Calculate a shift & mask that correspond to the value we wish to + * compare & exchange within the naturally aligned 4 byte integer + * that includes it. + */ + shift = (unsigned long)ptr & 0x3; + shift *= BITS_PER_BYTE; + old <<= shift; + new <<= shift; + mask <<= shift; + + /* + * Calculate a pointer to the naturally aligned 4 byte integer that + * includes our byte of interest, and load its value. + */ + ptr32 = (volatile u32 *)((unsigned long)ptr & ~0x3); + + asm volatile ( + "1: ll.w %0, %3 \n" + " and %1, %0, %z4 \n" + " bne %1, %z5, 2f \n" + " andn %1, %0, %z4 \n" + " or %1, %1, %z6 \n" + " sc.w %1, %2 \n" + " beqz %1, 1b \n" + " b 3f \n" + "2: \n" + __WEAK_LLSC_MB + "3: \n" + : "=&r" (old32), "=&r" (temp), "=ZC" (*ptr32) + : "ZC" (*ptr32), "Jr" (mask), "Jr" (old), "Jr" (new) + : "memory"); + + return (old32 & mask) >> shift; +} + +static __always_inline unsigned long +__cmpxchg(volatile void *ptr, unsigned long old, unsigned long new, unsigned int size) +{ + switch (size) { + case 1: + case 2: + return __cmpxchg_small(ptr, old, new, size); + + case 4: + return __cmpxchg_asm("ll.w", "sc.w", (volatile u32 *)ptr, + (u32)old, new); + + case 8: + return __cmpxchg_asm("ll.d", "sc.d", (volatile u64 *)ptr, + (u64)old, new); + + default: + BUILD_BUG(); + } + + return 0; +} + +#define arch_cmpxchg_local(ptr, old, new) \ + ((__typeof__(*(ptr))) \ + __cmpxchg((ptr), \ + (unsigned long)(__typeof__(*(ptr)))(old), \ + (unsigned long)(__typeof__(*(ptr)))(new), \ + sizeof(*(ptr)))) + +#define arch_cmpxchg(ptr, old, new) \ +({ \ + __typeof__(*(ptr)) __res; \ + \ + __res = arch_cmpxchg_local((ptr), (old), (new)); \ + \ + __res; \ +}) + +#ifdef CONFIG_64BIT +#define arch_cmpxchg64_local(ptr, o, n) \ + ({ \ + BUILD_BUG_ON(sizeof(*(ptr)) != 8); \ + arch_cmpxchg_local((ptr), (o), (n)); \ + }) + +#define arch_cmpxchg64(ptr, o, n) \ + ({ \ + BUILD_BUG_ON(sizeof(*(ptr)) != 8); \ + arch_cmpxchg((ptr), (o), (n)); \ + }) +#else +#include <asm-generic/cmpxchg-local.h> +#define arch_cmpxchg64_local(ptr, o, n) __generic_cmpxchg64_local((ptr), (o), (n)) +#define arch_cmpxchg64(ptr, o, n) arch_cmpxchg64_local((ptr), (o), (n)) +#endif + +#endif /* __ASM_CMPXCHG_H */ |