1 /* 2 * This file is subject to the terms and conditions of the GNU General Public 3 * License. See the file "COPYING" in the main directory of this archive 4 * for more details. 5 * 6 * Copyright (C) 2003, 06, 07 by Ralf Baechle (ralf@linux-mips.org) 7 */ 8 #ifndef __ASM_CMPXCHG_H 9 #define __ASM_CMPXCHG_H 10 11 #include <linux/irqflags.h> 12 13 #define __HAVE_ARCH_CMPXCHG 1 14 15 #define __cmpxchg_asm(ld, st, m, old, new) \ 16 ({ \ 17 __typeof(*(m)) __ret; \ 18 \ 19 if (kernel_uses_llsc && R10000_LLSC_WAR) { \ 20 __asm__ __volatile__( \ 21 " .set push \n" \ 22 " .set noat \n" \ 23 " .set mips3 \n" \ 24 "1: " ld " %0, %2 # __cmpxchg_asm \n" \ 25 " bne %0, %z3, 2f \n" \ 26 " .set mips0 \n" \ 27 " move $1, %z4 \n" \ 28 " .set mips3 \n" \ 29 " " st " $1, %1 \n" \ 30 " beqzl $1, 1b \n" \ 31 "2: \n" \ 32 " .set pop \n" \ 33 : "=&r" (__ret), "=R" (*m) \ 34 : "R" (*m), "Jr" (old), "Jr" (new) \ 35 : "memory"); \ 36 } else if (kernel_uses_llsc) { \ 37 __asm__ __volatile__( \ 38 " .set push \n" \ 39 " .set noat \n" \ 40 " .set mips3 \n" \ 41 "1: " ld " %0, %2 # __cmpxchg_asm \n" \ 42 " bne %0, %z3, 2f \n" \ 43 " .set mips0 \n" \ 44 " move $1, %z4 \n" \ 45 " .set mips3 \n" \ 46 " " st " $1, %1 \n" \ 47 " beqz $1, 1b \n" \ 48 " .set pop \n" \ 49 "2: \n" \ 50 : "=&r" (__ret), "=R" (*m) \ 51 : "R" (*m), "Jr" (old), "Jr" (new) \ 52 : "memory"); \ 53 } else { \ 54 unsigned long __flags; \ 55 \ 56 raw_local_irq_save(__flags); \ 57 __ret = *m; \ 58 if (__ret == old) \ 59 *m = new; \ 60 raw_local_irq_restore(__flags); \ 61 } \ 62 \ 63 __ret; \ 64 }) 65 66 /* 67 * This function doesn't exist, so you'll get a linker error 68 * if something tries to do an invalid cmpxchg(). 69 */ 70 extern void __cmpxchg_called_with_bad_pointer(void); 71 72 #define __cmpxchg(ptr, old, new, pre_barrier, post_barrier) \ 73 ({ \ 74 __typeof__(ptr) __ptr = (ptr); \ 75 __typeof__(*(ptr)) __old = (old); \ 76 __typeof__(*(ptr)) __new = (new); \ 77 __typeof__(*(ptr)) __res = 0; \ 78 \ 79 pre_barrier; \ 80 \ 81 switch (sizeof(*(__ptr))) { \ 82 case 4: \ 83 __res = __cmpxchg_asm("ll", "sc", __ptr, __old, __new); \ 84 break; \ 85 case 8: \ 86 if (sizeof(long) == 8) { \ 87 __res = __cmpxchg_asm("lld", "scd", __ptr, \ 88 __old, __new); \ 89 break; \ 90 } \ 91 default: \ 92 __cmpxchg_called_with_bad_pointer(); \ 93 break; \ 94 } \ 95 \ 96 post_barrier; \ 97 \ 98 __res; \ 99 }) 100 101 #define cmpxchg(ptr, old, new) __cmpxchg(ptr, old, new, smp_mb__before_llsc(), smp_llsc_mb()) 102 #define cmpxchg_local(ptr, old, new) __cmpxchg(ptr, old, new, , ) 103 104 #define cmpxchg64(ptr, o, n) \ 105 ({ \ 106 BUILD_BUG_ON(sizeof(*(ptr)) != 8); \ 107 cmpxchg((ptr), (o), (n)); \ 108 }) 109 110 #ifdef CONFIG_64BIT 111 #define cmpxchg64_local(ptr, o, n) \ 112 ({ \ 113 BUILD_BUG_ON(sizeof(*(ptr)) != 8); \ 114 cmpxchg_local((ptr), (o), (n)); \ 115 }) 116 #else 117 #include <asm-generic/cmpxchg-local.h> 118 #define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n)) 119 #endif 120 121 #endif /* __ASM_CMPXCHG_H */ 122