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 (cpu_has_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 (cpu_has_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, 3f \n" \ 48 "2: \n" \ 49 " .subsection 2 \n" \ 50 "3: b 1b \n" \ 51 " .previous \n" \ 52 " .set pop \n" \ 53 : "=&r" (__ret), "=R" (*m) \ 54 : "R" (*m), "Jr" (old), "Jr" (new) \ 55 : "memory"); \ 56 } else { \ 57 unsigned long __flags; \ 58 \ 59 raw_local_irq_save(__flags); \ 60 __ret = *m; \ 61 if (__ret == old) \ 62 *m = new; \ 63 raw_local_irq_restore(__flags); \ 64 } \ 65 \ 66 __ret; \ 67 }) 68 69 /* 70 * This function doesn't exist, so you'll get a linker error 71 * if something tries to do an invalid cmpxchg(). 72 */ 73 extern void __cmpxchg_called_with_bad_pointer(void); 74 75 #define __cmpxchg(ptr, old, new, barrier) \ 76 ({ \ 77 __typeof__(ptr) __ptr = (ptr); \ 78 __typeof__(*(ptr)) __old = (old); \ 79 __typeof__(*(ptr)) __new = (new); \ 80 __typeof__(*(ptr)) __res = 0; \ 81 \ 82 barrier; \ 83 \ 84 switch (sizeof(*(__ptr))) { \ 85 case 4: \ 86 __res = __cmpxchg_asm("ll", "sc", __ptr, __old, __new); \ 87 break; \ 88 case 8: \ 89 if (sizeof(long) == 8) { \ 90 __res = __cmpxchg_asm("lld", "scd", __ptr, \ 91 __old, __new); \ 92 break; \ 93 } \ 94 default: \ 95 __cmpxchg_called_with_bad_pointer(); \ 96 break; \ 97 } \ 98 \ 99 barrier; \ 100 \ 101 __res; \ 102 }) 103 104 #define cmpxchg(ptr, old, new) __cmpxchg(ptr, old, new, smp_llsc_mb()) 105 #define cmpxchg_local(ptr, old, new) __cmpxchg(ptr, old, new, ) 106 107 #define cmpxchg64(ptr, o, n) \ 108 ({ \ 109 BUILD_BUG_ON(sizeof(*(ptr)) != 8); \ 110 cmpxchg((ptr), (o), (n)); \ 111 }) 112 113 #ifdef CONFIG_64BIT 114 #define cmpxchg64_local(ptr, o, n) \ 115 ({ \ 116 BUILD_BUG_ON(sizeof(*(ptr)) != 8); \ 117 cmpxchg_local((ptr), (o), (n)); \ 118 }) 119 #else 120 #include <asm-generic/cmpxchg-local.h> 121 #define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n)) 122 #endif 123 124 #endif /* __ASM_CMPXCHG_H */ 125