1 #ifndef __ALPHA_SYSTEM_H 2 #error Do not include xchg.h directly! 3 #else 4 /* 5 * xchg/xchg_local and cmpxchg/cmpxchg_local share the same code 6 * except that local version do not have the expensive memory barrier. 7 * So this file is included twice from asm/system.h. 8 */ 9 10 /* 11 * Atomic exchange. 12 * Since it can be used to implement critical sections 13 * it must clobber "memory" (also for interrupts in UP). 14 */ 15 16 static inline unsigned long 17 ____xchg(_u8, volatile char *m, unsigned long val) 18 { 19 unsigned long ret, tmp, addr64; 20 21 __asm__ __volatile__( 22 " andnot %4,7,%3\n" 23 " insbl %1,%4,%1\n" 24 "1: ldq_l %2,0(%3)\n" 25 " extbl %2,%4,%0\n" 26 " mskbl %2,%4,%2\n" 27 " or %1,%2,%2\n" 28 " stq_c %2,0(%3)\n" 29 " beq %2,2f\n" 30 __ASM__MB 31 ".subsection 2\n" 32 "2: br 1b\n" 33 ".previous" 34 : "=&r" (ret), "=&r" (val), "=&r" (tmp), "=&r" (addr64) 35 : "r" ((long)m), "1" (val) : "memory"); 36 37 return ret; 38 } 39 40 static inline unsigned long 41 ____xchg(_u16, volatile short *m, unsigned long val) 42 { 43 unsigned long ret, tmp, addr64; 44 45 __asm__ __volatile__( 46 " andnot %4,7,%3\n" 47 " inswl %1,%4,%1\n" 48 "1: ldq_l %2,0(%3)\n" 49 " extwl %2,%4,%0\n" 50 " mskwl %2,%4,%2\n" 51 " or %1,%2,%2\n" 52 " stq_c %2,0(%3)\n" 53 " beq %2,2f\n" 54 __ASM__MB 55 ".subsection 2\n" 56 "2: br 1b\n" 57 ".previous" 58 : "=&r" (ret), "=&r" (val), "=&r" (tmp), "=&r" (addr64) 59 : "r" ((long)m), "1" (val) : "memory"); 60 61 return ret; 62 } 63 64 static inline unsigned long 65 ____xchg(_u32, volatile int *m, unsigned long val) 66 { 67 unsigned long dummy; 68 69 __asm__ __volatile__( 70 "1: ldl_l %0,%4\n" 71 " bis $31,%3,%1\n" 72 " stl_c %1,%2\n" 73 " beq %1,2f\n" 74 __ASM__MB 75 ".subsection 2\n" 76 "2: br 1b\n" 77 ".previous" 78 : "=&r" (val), "=&r" (dummy), "=m" (*m) 79 : "rI" (val), "m" (*m) : "memory"); 80 81 return val; 82 } 83 84 static inline unsigned long 85 ____xchg(_u64, volatile long *m, unsigned long val) 86 { 87 unsigned long dummy; 88 89 __asm__ __volatile__( 90 "1: ldq_l %0,%4\n" 91 " bis $31,%3,%1\n" 92 " stq_c %1,%2\n" 93 " beq %1,2f\n" 94 __ASM__MB 95 ".subsection 2\n" 96 "2: br 1b\n" 97 ".previous" 98 : "=&r" (val), "=&r" (dummy), "=m" (*m) 99 : "rI" (val), "m" (*m) : "memory"); 100 101 return val; 102 } 103 104 /* This function doesn't exist, so you'll get a linker error 105 if something tries to do an invalid xchg(). */ 106 extern void __xchg_called_with_bad_pointer(void); 107 108 static __always_inline unsigned long 109 ____xchg(, volatile void *ptr, unsigned long x, int size) 110 { 111 switch (size) { 112 case 1: 113 return ____xchg(_u8, ptr, x); 114 case 2: 115 return ____xchg(_u16, ptr, x); 116 case 4: 117 return ____xchg(_u32, ptr, x); 118 case 8: 119 return ____xchg(_u64, ptr, x); 120 } 121 __xchg_called_with_bad_pointer(); 122 return x; 123 } 124 125 /* 126 * Atomic compare and exchange. Compare OLD with MEM, if identical, 127 * store NEW in MEM. Return the initial value in MEM. Success is 128 * indicated by comparing RETURN with OLD. 129 * 130 * The memory barrier should be placed in SMP only when we actually 131 * make the change. If we don't change anything (so if the returned 132 * prev is equal to old) then we aren't acquiring anything new and 133 * we don't need any memory barrier as far I can tell. 134 */ 135 136 static inline unsigned long 137 ____cmpxchg(_u8, volatile char *m, unsigned char old, unsigned char new) 138 { 139 unsigned long prev, tmp, cmp, addr64; 140 141 __asm__ __volatile__( 142 " andnot %5,7,%4\n" 143 " insbl %1,%5,%1\n" 144 "1: ldq_l %2,0(%4)\n" 145 " extbl %2,%5,%0\n" 146 " cmpeq %0,%6,%3\n" 147 " beq %3,2f\n" 148 " mskbl %2,%5,%2\n" 149 " or %1,%2,%2\n" 150 " stq_c %2,0(%4)\n" 151 " beq %2,3f\n" 152 __ASM__MB 153 "2:\n" 154 ".subsection 2\n" 155 "3: br 1b\n" 156 ".previous" 157 : "=&r" (prev), "=&r" (new), "=&r" (tmp), "=&r" (cmp), "=&r" (addr64) 158 : "r" ((long)m), "Ir" (old), "1" (new) : "memory"); 159 160 return prev; 161 } 162 163 static inline unsigned long 164 ____cmpxchg(_u16, volatile short *m, unsigned short old, unsigned short new) 165 { 166 unsigned long prev, tmp, cmp, addr64; 167 168 __asm__ __volatile__( 169 " andnot %5,7,%4\n" 170 " inswl %1,%5,%1\n" 171 "1: ldq_l %2,0(%4)\n" 172 " extwl %2,%5,%0\n" 173 " cmpeq %0,%6,%3\n" 174 " beq %3,2f\n" 175 " mskwl %2,%5,%2\n" 176 " or %1,%2,%2\n" 177 " stq_c %2,0(%4)\n" 178 " beq %2,3f\n" 179 __ASM__MB 180 "2:\n" 181 ".subsection 2\n" 182 "3: br 1b\n" 183 ".previous" 184 : "=&r" (prev), "=&r" (new), "=&r" (tmp), "=&r" (cmp), "=&r" (addr64) 185 : "r" ((long)m), "Ir" (old), "1" (new) : "memory"); 186 187 return prev; 188 } 189 190 static inline unsigned long 191 ____cmpxchg(_u32, volatile int *m, int old, int new) 192 { 193 unsigned long prev, cmp; 194 195 __asm__ __volatile__( 196 "1: ldl_l %0,%5\n" 197 " cmpeq %0,%3,%1\n" 198 " beq %1,2f\n" 199 " mov %4,%1\n" 200 " stl_c %1,%2\n" 201 " beq %1,3f\n" 202 __ASM__MB 203 "2:\n" 204 ".subsection 2\n" 205 "3: br 1b\n" 206 ".previous" 207 : "=&r"(prev), "=&r"(cmp), "=m"(*m) 208 : "r"((long) old), "r"(new), "m"(*m) : "memory"); 209 210 return prev; 211 } 212 213 static inline unsigned long 214 ____cmpxchg(_u64, volatile long *m, unsigned long old, unsigned long new) 215 { 216 unsigned long prev, cmp; 217 218 __asm__ __volatile__( 219 "1: ldq_l %0,%5\n" 220 " cmpeq %0,%3,%1\n" 221 " beq %1,2f\n" 222 " mov %4,%1\n" 223 " stq_c %1,%2\n" 224 " beq %1,3f\n" 225 __ASM__MB 226 "2:\n" 227 ".subsection 2\n" 228 "3: br 1b\n" 229 ".previous" 230 : "=&r"(prev), "=&r"(cmp), "=m"(*m) 231 : "r"((long) old), "r"(new), "m"(*m) : "memory"); 232 233 return prev; 234 } 235 236 /* This function doesn't exist, so you'll get a linker error 237 if something tries to do an invalid cmpxchg(). */ 238 extern void __cmpxchg_called_with_bad_pointer(void); 239 240 static __always_inline unsigned long 241 ____cmpxchg(, volatile void *ptr, unsigned long old, unsigned long new, 242 int size) 243 { 244 switch (size) { 245 case 1: 246 return ____cmpxchg(_u8, ptr, old, new); 247 case 2: 248 return ____cmpxchg(_u16, ptr, old, new); 249 case 4: 250 return ____cmpxchg(_u32, ptr, old, new); 251 case 8: 252 return ____cmpxchg(_u64, ptr, old, new); 253 } 254 __cmpxchg_called_with_bad_pointer(); 255 return old; 256 } 257 258 #endif 259