include/asm-x86_64/bitops.h

   1 #ifndef _X86_64_BITOPS_H
   2 #define _X86_64_BITOPS_H
   3
   4 /*
   5  * Copyright 1992, Linus Torvalds.
   6  */
   7
   8
   9 #ifdef CONFIG_SMP
  10 #define LOCK_PREFIX "lock ; "
  11 #else
  12 #define LOCK_PREFIX ""
  13 #endif
  14
  15 #define ADDR (*(volatile long *) addr)
  16
  17 /**
  18  * set_bit - Atomically set a bit in memory
  19  * @nr: the bit to set
  20  * @addr: the address to start counting from
  21  *
  22  * This function is atomic and may not be reordered.  See __set_bit()
  23  * if you do not require the atomic guarantees.
  24  * Note that @nr may be almost arbitrarily large; this function is not
  25  * restricted to acting on a single-word quantity.
  26  */
  27 static __inline__ void set_bit(int nr, volatile void * addr)
  28 {
  29         __asm__ __volatile__( LOCK_PREFIX
  30                 "btsl %1,%0"
  31                 :"+m" (ADDR)
  32                 :"dIr" (nr) : "memory");
  33 }
  34
  35 /**
  36  * __set_bit - Set a bit in memory
  37  * @nr: the bit to set
  38  * @addr: the address to start counting from
  39  *
  40  * Unlike set_bit(), this function is non-atomic and may be reordered.
  41  * If it's called on the same region of memory simultaneously, the effect
  42  * may be that only one operation succeeds.
  43  */
  44 static __inline__ void __set_bit(int nr, volatile void * addr)
  45 {
  46         __asm__ volatile(
  47                 "btsl %1,%0"
  48                 :"+m" (ADDR)
  49                 :"dIr" (nr) : "memory");
  50 }
  51
  52 /**
  53  * clear_bit - Clears a bit in memory
  54  * @nr: Bit to clear
  55  * @addr: Address to start counting from
  56  *
  57  * clear_bit() is atomic and may not be reordered.  However, it does
  58  * not contain a memory barrier, so if it is used for locking purposes,
  59  * you should call smp_mb__before_clear_bit() and/or smp_mb__after_clear_bit()
  60  * in order to ensure changes are visible on other processors.
  61  */
  62 static __inline__ void clear_bit(int nr, volatile void * addr)
  63 {
  64         __asm__ __volatile__( LOCK_PREFIX
  65                 "btrl %1,%0"
  66                 :"+m" (ADDR)
  67                 :"dIr" (nr));
  68 }
  69
  70 static __inline__ void __clear_bit(int nr, volatile void * addr)
  71 {
  72         __asm__ __volatile__(
  73                 "btrl %1,%0"
  74                 :"+m" (ADDR)
  75                 :"dIr" (nr));
  76 }
  77
  78 #define smp_mb__before_clear_bit()      barrier()
  79 #define smp_mb__after_clear_bit()       barrier()
  80
  81 /**
  82  * __change_bit - Toggle a bit in memory
  83  * @nr: the bit to change
  84  * @addr: the address to start counting from
  85  *
  86  * Unlike change_bit(), this function is non-atomic and may be reordered.
  87  * If it's called on the same region of memory simultaneously, the effect
  88  * may be that only one operation succeeds.
  89  */
  90 static __inline__ void __change_bit(int nr, volatile void * addr)
  91 {
  92         __asm__ __volatile__(
  93                 "btcl %1,%0"
  94                 :"+m" (ADDR)
  95                 :"dIr" (nr));
  96 }
  97
  98 /**
  99  * change_bit - Toggle a bit in memory
 100  * @nr: Bit to change
 101  * @addr: Address to start counting from
 102  *
 103  * change_bit() is atomic and may not be reordered.
 104  * Note that @nr may be almost arbitrarily large; this function is not
 105  * restricted to acting on a single-word quantity.
 106  */
 107 static __inline__ void change_bit(int nr, volatile void * addr)
 108 {
 109         __asm__ __volatile__( LOCK_PREFIX
 110                 "btcl %1,%0"
 111                 :"+m" (ADDR)
 112                 :"dIr" (nr));
 113 }
 114
 115 /**
 116  * test_and_set_bit - Set a bit and return its old value
 117  * @nr: Bit to set
 118  * @addr: Address to count from
 119  *
 120  * This operation is atomic and cannot be reordered.
 121  * It also implies a memory barrier.
 122  */
 123 static __inline__ int test_and_set_bit(int nr, volatile void * addr)
 124 {
 125         int oldbit;
 126
 127         __asm__ __volatile__( LOCK_PREFIX
 128                 "btsl %2,%1\n\tsbbl %0,%0"
 129                 :"=r" (oldbit),"+m" (ADDR)
 130                 :"dIr" (nr) : "memory");
 131         return oldbit;
 132 }
 133
 134 /**
 135  * __test_and_set_bit - Set a bit and return its old value
 136  * @nr: Bit to set
 137  * @addr: Address to count from
 138  *
 139  * This operation is non-atomic and can be reordered.
 140  * If two examples of this operation race, one can appear to succeed
 141  * but actually fail.  You must protect multiple accesses with a lock.
 142  */
 143 static __inline__ int __test_and_set_bit(int nr, volatile void * addr)
 144 {
 145         int oldbit;
 146
 147         __asm__(
 148                 "btsl %2,%1\n\tsbbl %0,%0"
 149                 :"=r" (oldbit),"+m" (ADDR)
 150                 :"dIr" (nr));
 151         return oldbit;
 152 }
 153
 154 /**
 155  * test_and_clear_bit - Clear a bit and return its old value
 156  * @nr: Bit to clear
 157  * @addr: Address to count from
 158  *
 159  * This operation is atomic and cannot be reordered.
 160  * It also implies a memory barrier.
 161  */
 162 static __inline__ int test_and_clear_bit(int nr, volatile void * addr)
 163 {
 164         int oldbit;
 165
 166         __asm__ __volatile__( LOCK_PREFIX
 167                 "btrl %2,%1\n\tsbbl %0,%0"
 168                 :"=r" (oldbit),"+m" (ADDR)
 169                 :"dIr" (nr) : "memory");
 170         return oldbit;
 171 }
 172
 173 /**
 174  * __test_and_clear_bit - Clear a bit and return its old value
 175  * @nr: Bit to clear
 176  * @addr: Address to count from
 177  *
 178  * This operation is non-atomic and can be reordered.
 179  * If two examples of this operation race, one can appear to succeed
 180  * but actually fail.  You must protect multiple accesses with a lock.
 181  */
 182 static __inline__ int __test_and_clear_bit(int nr, volatile void * addr)
 183 {
 184         int oldbit;
 185
 186         __asm__(
 187                 "btrl %2,%1\n\tsbbl %0,%0"
 188                 :"=r" (oldbit),"+m" (ADDR)
 189                 :"dIr" (nr));
 190         return oldbit;
 191 }
 192
 193 /* WARNING: non atomic and it can be reordered! */
 194 static __inline__ int __test_and_change_bit(int nr, volatile void * addr)
 195 {
 196         int oldbit;
 197
 198         __asm__ __volatile__(
 199                 "btcl %2,%1\n\tsbbl %0,%0"
 200                 :"=r" (oldbit),"+m" (ADDR)
 201                 :"dIr" (nr) : "memory");
 202         return oldbit;
 203 }
 204
 205 /**
 206  * test_and_change_bit - Change a bit and return its old value
 207  * @nr: Bit to change
 208  * @addr: Address to count from
 209  *
 210  * This operation is atomic and cannot be reordered.
 211  * It also implies a memory barrier.
 212  */
 213 static __inline__ int test_and_change_bit(int nr, volatile void * addr)
 214 {
 215         int oldbit;
 216
 217         __asm__ __volatile__( LOCK_PREFIX
 218                 "btcl %2,%1\n\tsbbl %0,%0"
 219                 :"=r" (oldbit),"+m" (ADDR)
 220                 :"dIr" (nr) : "memory");
 221         return oldbit;
 222 }
 223
 224 #if 0 /* Fool kernel-doc since it doesn't do macros yet */
 225 /**
 226  * test_bit - Determine whether a bit is set
 227  * @nr: bit number to test
 228  * @addr: Address to start counting from
 229  */
 230 static int test_bit(int nr, const volatile void * addr);
 231 #endif
 232
 233 static __inline__ int constant_test_bit(int nr, const volatile void * addr)
 234 {
 235         return ((1UL << (nr & 31)) & (((const volatile unsigned int *) addr)[nr >> 5])) != 0;
 236 }
 237
 238 static __inline__ int variable_test_bit(int nr, volatile const void * addr)
 239 {
 240         int oldbit;
 241
 242         __asm__ __volatile__(
 243                 "btl %2,%1\n\tsbbl %0,%0"
 244                 :"=r" (oldbit)
 245                 :"m" (ADDR),"dIr" (nr));
 246         return oldbit;
 247 }
 248
 249 #define test_bit(nr,addr) \
 250 (__builtin_constant_p(nr) ? \
 251  constant_test_bit((nr),(addr)) : \
 252  variable_test_bit((nr),(addr)))
 253
 254 #undef ADDR
 255
 256 extern long find_first_zero_bit(const unsigned long * addr, unsigned long size);
 257 extern long find_next_zero_bit (const unsigned long * addr, long size, long offset);
 258 extern long find_first_bit(const unsigned long * addr, unsigned long size);
 259 extern long find_next_bit(const unsigned long * addr, long size, long offset);
 260
 261 /* return index of first bet set in val or max when no bit is set */
 262 static inline unsigned long __scanbit(unsigned long val, unsigned long max)
 263 {
 264         asm("bsfq %1,%0 ; cmovz %2,%0" : "=&r" (val) : "r" (val), "r" (max));
 265         return val;
 266 }
 267
 268 #define find_first_bit(addr,size) \
 269 ((__builtin_constant_p(size) && (size) <= BITS_PER_LONG ? \
 270   (__scanbit(*(unsigned long *)addr,(size))) : \
 271   find_first_bit(addr,size)))
 272
 273 #define find_next_bit(addr,size,off) \
 274 ((__builtin_constant_p(size) && (size) <= BITS_PER_LONG ?         \
 275   ((off) + (__scanbit((*(unsigned long *)addr) >> (off),(size)-(off)))) : \
 276         find_next_bit(addr,size,off)))
 277
 278 #define find_first_zero_bit(addr,size) \
 279 ((__builtin_constant_p(size) && (size) <= BITS_PER_LONG ? \
 280   (__scanbit(~*(unsigned long *)addr,(size))) : \
 281         find_first_zero_bit(addr,size)))
 282
 283 #define find_next_zero_bit(addr,size,off) \
 284 ((__builtin_constant_p(size) && (size) <= BITS_PER_LONG ?         \
 285   ((off)+(__scanbit(~(((*(unsigned long *)addr)) >> (off)),(size)-(off)))) : \
 286         find_next_zero_bit(addr,size,off)))
 287
 288 /*
 289  * Find string of zero bits in a bitmap. -1 when not found.
 290  */
 291 extern unsigned long
 292 find_next_zero_string(unsigned long *bitmap, long start, long nbits, int len);
 293
 294 static inline void set_bit_string(unsigned long *bitmap, unsigned long i,
 295                                   int len)
 296 {
 297         unsigned long end = i + len;
 298         while (i < end) {
 299                 __set_bit(i, bitmap);
 300                 i++;
 301         }
 302 }
 303
 304 static inline void __clear_bit_string(unsigned long *bitmap, unsigned long i,
 305                                     int len)
 306 {
 307         unsigned long end = i + len;
 308         while (i < end) {
 309                 __clear_bit(i, bitmap);
 310                 i++;
 311         }
 312 }
 313
 314 /**
 315  * ffz - find first zero in word.
 316  * @word: The word to search
 317  *
 318  * Undefined if no zero exists, so code should check against ~0UL first.
 319  */
 320 static __inline__ unsigned long ffz(unsigned long word)
 321 {
 322         __asm__("bsfq %1,%0"
 323                 :"=r" (word)
 324                 :"r" (~word));
 325         return word;
 326 }
 327
 328 /**
 329  * __ffs - find first bit in word.
 330  * @word: The word to search
 331  *
 332  * Undefined if no bit exists, so code should check against 0 first.
 333  */
 334 static __inline__ unsigned long __ffs(unsigned long word)
 335 {
 336         __asm__("bsfq %1,%0"
 337                 :"=r" (word)
 338                 :"rm" (word));
 339         return word;
 340 }
 341
 342 /*
 343  * __fls: find last bit set.
 344  * @word: The word to search
 345  *
 346  * Undefined if no zero exists, so code should check against ~0UL first.
 347  */
 348 static __inline__ unsigned long __fls(unsigned long word)
 349 {
 350         __asm__("bsrq %1,%0"
 351                 :"=r" (word)
 352                 :"rm" (word));
 353         return word;
 354 }
 355
 356 #ifdef __KERNEL__
 357
 358 #include <asm-generic/bitops/sched.h>
 359
 360 /**
 361  * ffs - find first bit set
 362  * @x: the word to search
 363  *
 364  * This is defined the same way as
 365  * the libc and compiler builtin ffs routines, therefore
 366  * differs in spirit from the above ffz (man ffs).
 367  */
 368 static __inline__ int ffs(int x)
 369 {
 370         int r;
 371
 372         __asm__("bsfl %1,%0\n\t"
 373                 "cmovzl %2,%0"
 374                 : "=r" (r) : "rm" (x), "r" (-1));
 375         return r+1;
 376 }
 377
 378 /**
 379  * fls64 - find last bit set in 64 bit word
 380  * @x: the word to search
 381  *
 382  * This is defined the same way as fls.
 383  */
 384 static __inline__ int fls64(__u64 x)
 385 {
 386         if (x == 0)
 387                 return 0;
 388         return __fls(x) + 1;
 389 }
 390
 391 /**
 392  * fls - find last bit set
 393  * @x: the word to search
 394  *
 395  * This is defined the same way as ffs.
 396  */
 397 static __inline__ int fls(int x)
 398 {
 399         int r;
 400
 401         __asm__("bsrl %1,%0\n\t"
 402                 "cmovzl %2,%0"
 403                 : "=&r" (r) : "rm" (x), "rm" (-1));
 404         return r+1;
 405 }
 406
 407 #include <asm-generic/bitops/hweight.h>
 408
 409 #endif /* __KERNEL__ */
 410
 411 #ifdef __KERNEL__
 412
 413 #include <asm-generic/bitops/ext2-non-atomic.h>
 414
 415 #define ext2_set_bit_atomic(lock,nr,addr) \
 416                 test_and_set_bit((nr),(unsigned long*)addr)
 417 #define ext2_clear_bit_atomic(lock,nr,addr) \
 418                 test_and_clear_bit((nr),(unsigned long*)addr)
 419
 420 #include <asm-generic/bitops/minix.h>
 421
 422 #endif /* __KERNEL__ */
 423
 424 #endif /* _X86_64_BITOPS_H */