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/bug.h> 12 #include <linux/irqflags.h> 13 #include <asm/war.h> 14 15 static inline unsigned long __xchg_u32(volatile int * m, unsigned int val) 16 { 17 __u32 retval; 18 19 smp_mb__before_llsc(); 20 21 if (kernel_uses_llsc && R10000_LLSC_WAR) { 22 unsigned long dummy; 23 24 __asm__ __volatile__( 25 " .set arch=r4000 \n" 26 "1: ll %0, %3 # xchg_u32 \n" 27 " .set mips0 \n" 28 " move %2, %z4 \n" 29 " .set arch=r4000 \n" 30 " sc %2, %1 \n" 31 " beqzl %2, 1b \n" 32 " .set mips0 \n" 33 : "=&r" (retval), "=m" (*m), "=&r" (dummy) 34 : "R" (*m), "Jr" (val) 35 : "memory"); 36 } else if (kernel_uses_llsc) { 37 unsigned long dummy; 38 39 do { 40 __asm__ __volatile__( 41 " .set arch=r4000 \n" 42 " ll %0, %3 # xchg_u32 \n" 43 " .set mips0 \n" 44 " move %2, %z4 \n" 45 " .set arch=r4000 \n" 46 " sc %2, %1 \n" 47 " .set mips0 \n" 48 : "=&r" (retval), "=m" (*m), "=&r" (dummy) 49 : "R" (*m), "Jr" (val) 50 : "memory"); 51 } while (unlikely(!dummy)); 52 } else { 53 unsigned long flags; 54 55 raw_local_irq_save(flags); 56 retval = *m; 57 *m = val; 58 raw_local_irq_restore(flags); /* implies memory barrier */ 59 } 60 61 smp_llsc_mb(); 62 63 return retval; 64 } 65 66 #ifdef CONFIG_64BIT 67 static inline __u64 __xchg_u64(volatile __u64 * m, __u64 val) 68 { 69 __u64 retval; 70 71 smp_mb__before_llsc(); 72 73 if (kernel_uses_llsc && R10000_LLSC_WAR) { 74 unsigned long dummy; 75 76 __asm__ __volatile__( 77 " .set arch=r4000 \n" 78 "1: lld %0, %3 # xchg_u64 \n" 79 " move %2, %z4 \n" 80 " scd %2, %1 \n" 81 " beqzl %2, 1b \n" 82 " .set mips0 \n" 83 : "=&r" (retval), "=m" (*m), "=&r" (dummy) 84 : "R" (*m), "Jr" (val) 85 : "memory"); 86 } else if (kernel_uses_llsc) { 87 unsigned long dummy; 88 89 do { 90 __asm__ __volatile__( 91 " .set arch=r4000 \n" 92 " lld %0, %3 # xchg_u64 \n" 93 " move %2, %z4 \n" 94 " scd %2, %1 \n" 95 " .set mips0 \n" 96 : "=&r" (retval), "=m" (*m), "=&r" (dummy) 97 : "R" (*m), "Jr" (val) 98 : "memory"); 99 } while (unlikely(!dummy)); 100 } else { 101 unsigned long flags; 102 103 raw_local_irq_save(flags); 104 retval = *m; 105 *m = val; 106 raw_local_irq_restore(flags); /* implies memory barrier */ 107 } 108 109 smp_llsc_mb(); 110 111 return retval; 112 } 113 #else 114 extern __u64 __xchg_u64_unsupported_on_32bit_kernels(volatile __u64 * m, __u64 val); 115 #define __xchg_u64 __xchg_u64_unsupported_on_32bit_kernels 116 #endif 117 118 static inline unsigned long __xchg(unsigned long x, volatile void * ptr, int size) 119 { 120 switch (size) { 121 case 4: 122 return __xchg_u32(ptr, x); 123 case 8: 124 return __xchg_u64(ptr, x); 125 } 126 127 return x; 128 } 129 130 #define xchg(ptr, x) \ 131 ({ \ 132 BUILD_BUG_ON(sizeof(*(ptr)) & ~0xc); \ 133 \ 134 ((__typeof__(*(ptr))) \ 135 __xchg((unsigned long)(x), (ptr), sizeof(*(ptr)))); \ 136 }) 137 138 #define __HAVE_ARCH_CMPXCHG 1 139 140 #define __cmpxchg_asm(ld, st, m, old, new) \ 141 ({ \ 142 __typeof(*(m)) __ret; \ 143 \ 144 if (kernel_uses_llsc && R10000_LLSC_WAR) { \ 145 __asm__ __volatile__( \ 146 " .set push \n" \ 147 " .set noat \n" \ 148 " .set arch=r4000 \n" \ 149 "1: " ld " %0, %2 # __cmpxchg_asm \n" \ 150 " bne %0, %z3, 2f \n" \ 151 " .set mips0 \n" \ 152 " move $1, %z4 \n" \ 153 " .set arch=r4000 \n" \ 154 " " st " $1, %1 \n" \ 155 " beqzl $1, 1b \n" \ 156 "2: \n" \ 157 " .set pop \n" \ 158 : "=&r" (__ret), "=R" (*m) \ 159 : "R" (*m), "Jr" (old), "Jr" (new) \ 160 : "memory"); \ 161 } else if (kernel_uses_llsc) { \ 162 __asm__ __volatile__( \ 163 " .set push \n" \ 164 " .set noat \n" \ 165 " .set arch=r4000 \n" \ 166 "1: " ld " %0, %2 # __cmpxchg_asm \n" \ 167 " bne %0, %z3, 2f \n" \ 168 " .set mips0 \n" \ 169 " move $1, %z4 \n" \ 170 " .set arch=r4000 \n" \ 171 " " st " $1, %1 \n" \ 172 " beqz $1, 1b \n" \ 173 " .set pop \n" \ 174 "2: \n" \ 175 : "=&r" (__ret), "=R" (*m) \ 176 : "R" (*m), "Jr" (old), "Jr" (new) \ 177 : "memory"); \ 178 } else { \ 179 unsigned long __flags; \ 180 \ 181 raw_local_irq_save(__flags); \ 182 __ret = *m; \ 183 if (__ret == old) \ 184 *m = new; \ 185 raw_local_irq_restore(__flags); \ 186 } \ 187 \ 188 __ret; \ 189 }) 190 191 /* 192 * This function doesn't exist, so you'll get a linker error 193 * if something tries to do an invalid cmpxchg(). 194 */ 195 extern void __cmpxchg_called_with_bad_pointer(void); 196 197 #define __cmpxchg(ptr, old, new, pre_barrier, post_barrier) \ 198 ({ \ 199 __typeof__(ptr) __ptr = (ptr); \ 200 __typeof__(*(ptr)) __old = (old); \ 201 __typeof__(*(ptr)) __new = (new); \ 202 __typeof__(*(ptr)) __res = 0; \ 203 \ 204 pre_barrier; \ 205 \ 206 switch (sizeof(*(__ptr))) { \ 207 case 4: \ 208 __res = __cmpxchg_asm("ll", "sc", __ptr, __old, __new); \ 209 break; \ 210 case 8: \ 211 if (sizeof(long) == 8) { \ 212 __res = __cmpxchg_asm("lld", "scd", __ptr, \ 213 __old, __new); \ 214 break; \ 215 } \ 216 default: \ 217 __cmpxchg_called_with_bad_pointer(); \ 218 break; \ 219 } \ 220 \ 221 post_barrier; \ 222 \ 223 __res; \ 224 }) 225 226 #define cmpxchg(ptr, old, new) __cmpxchg(ptr, old, new, smp_mb__before_llsc(), smp_llsc_mb()) 227 #define cmpxchg_local(ptr, old, new) __cmpxchg(ptr, old, new, , ) 228 229 #define cmpxchg64(ptr, o, n) \ 230 ({ \ 231 BUILD_BUG_ON(sizeof(*(ptr)) != 8); \ 232 cmpxchg((ptr), (o), (n)); \ 233 }) 234 235 #ifdef CONFIG_64BIT 236 #define cmpxchg64_local(ptr, o, n) \ 237 ({ \ 238 BUILD_BUG_ON(sizeof(*(ptr)) != 8); \ 239 cmpxchg_local((ptr), (o), (n)); \ 240 }) 241 #else 242 #include <asm-generic/cmpxchg-local.h> 243 #define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n)) 244 #endif 245 246 #endif /* __ASM_CMPXCHG_H */ 247