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