include/asm-powerpc/bitops.h

   1 /*
   2  * PowerPC atomic bit operations.
   3  *
   4  * Merged version by David Gibson <david@gibson.dropbear.id.au>.
   5  * Based on ppc64 versions by: Dave Engebretsen, Todd Inglett, Don
   6  * Reed, Pat McCarthy, Peter Bergner, Anton Blanchard.  They
   7  * originally took it from the ppc32 code.
   8  *
   9  * Within a word, bits are numbered LSB first.  Lot's of places make
  10  * this assumption by directly testing bits with (val & (1<<nr)).
  11  * This can cause confusion for large (> 1 word) bitmaps on a
  12  * big-endian system because, unlike little endian, the number of each
  13  * bit depends on the word size.
  14  *
  15  * The bitop functions are defined to work on unsigned longs, so for a
  16  * ppc64 system the bits end up numbered:
  17  *   |63..............0|127............64|191...........128|255...........196|
  18  * and on ppc32:
  19  *   |31.....0|63....31|95....64|127...96|159..128|191..160|223..192|255..224|
  20  *
  21  * There are a few little-endian macros used mostly for filesystem
  22  * bitmaps, these work on similar bit arrays layouts, but
  23  * byte-oriented:
  24  *   |7...0|15...8|23...16|31...24|39...32|47...40|55...48|63...56|
  25  *
  26  * The main difference is that bit 3-5 (64b) or 3-4 (32b) in the bit
  27  * number field needs to be reversed compared to the big-endian bit
  28  * fields. This can be achieved by XOR with 0x38 (64b) or 0x18 (32b).
  29  *
  30  * This program is free software; you can redistribute it and/or
  31  * modify it under the terms of the GNU General Public License
  32  * as published by the Free Software Foundation; either version
  33  * 2 of the License, or (at your option) any later version.
  34  */
  35
  36 #ifndef _ASM_POWERPC_BITOPS_H
  37 #define _ASM_POWERPC_BITOPS_H
  38
  39 #ifdef __KERNEL__
  40
  41 #ifndef _LINUX_BITOPS_H
  42 #error only <linux/bitops.h> can be included directly
  43 #endif
  44
  45 #include <linux/compiler.h>
  46 #include <asm/asm-compat.h>
  47 #include <asm/synch.h>
  48
  49 /*
  50  * clear_bit doesn't imply a memory barrier
  51  */
  52 #define smp_mb__before_clear_bit()      smp_mb()
  53 #define smp_mb__after_clear_bit()       smp_mb()
  54
  55 #define BITOP_MASK(nr)          (1UL << ((nr) % BITS_PER_LONG))
  56 #define BITOP_WORD(nr)          ((nr) / BITS_PER_LONG)
  57 #define BITOP_LE_SWIZZLE        ((BITS_PER_LONG-1) & ~0x7)
  58
  59 static __inline__ void set_bit(int nr, volatile unsigned long *addr)
  60 {
  61         unsigned long old;
  62         unsigned long mask = BITOP_MASK(nr);
  63         unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr);
  64
  65         __asm__ __volatile__(
  66 "1:"    PPC_LLARX "%0,0,%3      # set_bit\n"
  67         "or     %0,%0,%2\n"
  68         PPC405_ERR77(0,%3)
  69         PPC_STLCX "%0,0,%3\n"
  70         "bne-   1b"
  71         : "=&r" (old), "+m" (*p)
  72         : "r" (mask), "r" (p)
  73         : "cc" );
  74 }
  75
  76 static __inline__ void clear_bit(int nr, volatile unsigned long *addr)
  77 {
  78         unsigned long old;
  79         unsigned long mask = BITOP_MASK(nr);
  80         unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr);
  81
  82         __asm__ __volatile__(
  83 "1:"    PPC_LLARX "%0,0,%3      # clear_bit\n"
  84         "andc   %0,%0,%2\n"
  85         PPC405_ERR77(0,%3)
  86         PPC_STLCX "%0,0,%3\n"
  87         "bne-   1b"
  88         : "=&r" (old), "+m" (*p)
  89         : "r" (mask), "r" (p)
  90         : "cc" );
  91 }
  92
  93 static __inline__ void clear_bit_unlock(int nr, volatile unsigned long *addr)
  94 {
  95         unsigned long old;
  96         unsigned long mask = BITOP_MASK(nr);
  97         unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr);
  98
  99         __asm__ __volatile__(
 100         LWSYNC_ON_SMP
 101 "1:"    PPC_LLARX "%0,0,%3      # clear_bit_unlock\n"
 102         "andc   %0,%0,%2\n"
 103         PPC405_ERR77(0,%3)
 104         PPC_STLCX "%0,0,%3\n"
 105         "bne-   1b"
 106         : "=&r" (old), "+m" (*p)
 107         : "r" (mask), "r" (p)
 108         : "cc", "memory");
 109 }
 110
 111 static __inline__ void change_bit(int nr, volatile unsigned long *addr)
 112 {
 113         unsigned long old;
 114         unsigned long mask = BITOP_MASK(nr);
 115         unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr);
 116
 117         __asm__ __volatile__(
 118 "1:"    PPC_LLARX "%0,0,%3      # change_bit\n"
 119         "xor    %0,%0,%2\n"
 120         PPC405_ERR77(0,%3)
 121         PPC_STLCX "%0,0,%3\n"
 122         "bne-   1b"
 123         : "=&r" (old), "+m" (*p)
 124         : "r" (mask), "r" (p)
 125         : "cc" );
 126 }
 127
 128 static __inline__ int test_and_set_bit(unsigned long nr,
 129                                        volatile unsigned long *addr)
 130 {
 131         unsigned long old, t;
 132         unsigned long mask = BITOP_MASK(nr);
 133         unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr);
 134
 135         __asm__ __volatile__(
 136         LWSYNC_ON_SMP
 137 "1:"    PPC_LLARX "%0,0,%3              # test_and_set_bit\n"
 138         "or     %1,%0,%2 \n"
 139         PPC405_ERR77(0,%3)
 140         PPC_STLCX "%1,0,%3 \n"
 141         "bne-   1b"
 142         ISYNC_ON_SMP
 143         : "=&r" (old), "=&r" (t)
 144         : "r" (mask), "r" (p)
 145         : "cc", "memory");
 146
 147         return (old & mask) != 0;
 148 }
 149
 150 static __inline__ int test_and_set_bit_lock(unsigned long nr,
 151                                        volatile unsigned long *addr)
 152 {
 153         unsigned long old, t;
 154         unsigned long mask = BITOP_MASK(nr);
 155         unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr);
 156
 157         __asm__ __volatile__(
 158 "1:"    PPC_LLARX "%0,0,%3              # test_and_set_bit_lock\n"
 159         "or     %1,%0,%2 \n"
 160         PPC405_ERR77(0,%3)
 161         PPC_STLCX "%1,0,%3 \n"
 162         "bne-   1b"
 163         ISYNC_ON_SMP
 164         : "=&r" (old), "=&r" (t)
 165         : "r" (mask), "r" (p)
 166         : "cc", "memory");
 167
 168         return (old & mask) != 0;
 169 }
 170
 171 static __inline__ int test_and_clear_bit(unsigned long nr,
 172                                          volatile unsigned long *addr)
 173 {
 174         unsigned long old, t;
 175         unsigned long mask = BITOP_MASK(nr);
 176         unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr);
 177
 178         __asm__ __volatile__(
 179         LWSYNC_ON_SMP
 180 "1:"    PPC_LLARX "%0,0,%3              # test_and_clear_bit\n"
 181         "andc   %1,%0,%2 \n"
 182         PPC405_ERR77(0,%3)
 183         PPC_STLCX "%1,0,%3 \n"
 184         "bne-   1b"
 185         ISYNC_ON_SMP
 186         : "=&r" (old), "=&r" (t)
 187         : "r" (mask), "r" (p)
 188         : "cc", "memory");
 189
 190         return (old & mask) != 0;
 191 }
 192
 193 static __inline__ int test_and_change_bit(unsigned long nr,
 194                                           volatile unsigned long *addr)
 195 {
 196         unsigned long old, t;
 197         unsigned long mask = BITOP_MASK(nr);
 198         unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr);
 199
 200         __asm__ __volatile__(
 201         LWSYNC_ON_SMP
 202 "1:"    PPC_LLARX "%0,0,%3              # test_and_change_bit\n"
 203         "xor    %1,%0,%2 \n"
 204         PPC405_ERR77(0,%3)
 205         PPC_STLCX "%1,0,%3 \n"
 206         "bne-   1b"
 207         ISYNC_ON_SMP
 208         : "=&r" (old), "=&r" (t)
 209         : "r" (mask), "r" (p)
 210         : "cc", "memory");
 211
 212         return (old & mask) != 0;
 213 }
 214
 215 static __inline__ void set_bits(unsigned long mask, unsigned long *addr)
 216 {
 217         unsigned long old;
 218
 219         __asm__ __volatile__(
 220 "1:"    PPC_LLARX "%0,0,%3         # set_bits\n"
 221         "or     %0,%0,%2\n"
 222         PPC_STLCX "%0,0,%3\n"
 223         "bne-   1b"
 224         : "=&r" (old), "+m" (*addr)
 225         : "r" (mask), "r" (addr)
 226         : "cc");
 227 }
 228
 229 #include <asm-generic/bitops/non-atomic.h>
 230
 231 static __inline__ void __clear_bit_unlock(int nr, volatile unsigned long *addr)
 232 {
 233         __asm__ __volatile__(LWSYNC_ON_SMP "" ::: "memory");
 234         __clear_bit(nr, addr);
 235 }
 236
 237 /*
 238  * Return the zero-based bit position (LE, not IBM bit numbering) of
 239  * the most significant 1-bit in a double word.
 240  */
 241 static __inline__ __attribute__((const))
 242 int __ilog2(unsigned long x)
 243 {
 244         int lz;
 245
 246         asm (PPC_CNTLZL "%0,%1" : "=r" (lz) : "r" (x));
 247         return BITS_PER_LONG - 1 - lz;
 248 }
 249
 250 static inline __attribute__((const))
 251 int __ilog2_u32(u32 n)
 252 {
 253         int bit;
 254         asm ("cntlzw %0,%1" : "=r" (bit) : "r" (n));
 255         return 31 - bit;
 256 }
 257
 258 #ifdef __powerpc64__
 259 static inline __attribute__((const))
 260 int __ilog2_u64(u64 n)
 261 {
 262         int bit;
 263         asm ("cntlzd %0,%1" : "=r" (bit) : "r" (n));
 264         return 63 - bit;
 265 }
 266 #endif
 267
 268 /*
 269  * Determines the bit position of the least significant 0 bit in the
 270  * specified double word. The returned bit position will be
 271  * zero-based, starting from the right side (63/31 - 0).
 272  */
 273 static __inline__ unsigned long ffz(unsigned long x)
 274 {
 275         /* no zero exists anywhere in the 8 byte area. */
 276         if ((x = ~x) == 0)
 277                 return BITS_PER_LONG;
 278
 279         /*
 280          * Calculate the bit position of the least signficant '1' bit in x
 281          * (since x has been changed this will actually be the least signficant
 282          * '0' bit in * the original x).  Note: (x & -x) gives us a mask that
 283          * is the least significant * (RIGHT-most) 1-bit of the value in x.
 284          */
 285         return __ilog2(x & -x);
 286 }
 287
 288 static __inline__ int __ffs(unsigned long x)
 289 {
 290         return __ilog2(x & -x);
 291 }
 292
 293 /*
 294  * ffs: find first bit set. This is defined the same way as
 295  * the libc and compiler builtin ffs routines, therefore
 296  * differs in spirit from the above ffz (man ffs).
 297  */
 298 static __inline__ int ffs(int x)
 299 {
 300         unsigned long i = (unsigned long)x;
 301         return __ilog2(i & -i) + 1;
 302 }
 303
 304 /*
 305  * fls: find last (most-significant) bit set.
 306  * Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
 307  */
 308 static __inline__ int fls(unsigned int x)
 309 {
 310         int lz;
 311
 312         asm ("cntlzw %0,%1" : "=r" (lz) : "r" (x));
 313         return 32 - lz;
 314 }
 315
 316 static __inline__ unsigned long __fls(unsigned long x)
 317 {
 318         return __ilog2(x);
 319 }
 320
 321 /*
 322  * 64-bit can do this using one cntlzd (count leading zeroes doubleword)
 323  * instruction; for 32-bit we use the generic version, which does two
 324  * 32-bit fls calls.
 325  */
 326 #ifdef __powerpc64__
 327 static __inline__ int fls64(__u64 x)
 328 {
 329         int lz;
 330
 331         asm ("cntlzd %0,%1" : "=r" (lz) : "r" (x));
 332         return 64 - lz;
 333 }
 334 #else
 335 #include <asm-generic/bitops/fls64.h>
 336 #endif /* __powerpc64__ */
 337
 338 #include <asm-generic/bitops/hweight.h>
 339 #include <asm-generic/bitops/find.h>
 340
 341 /* Little-endian versions */
 342
 343 static __inline__ int test_le_bit(unsigned long nr,
 344                                   __const__ unsigned long *addr)
 345 {
 346         __const__ unsigned char *tmp = (__const__ unsigned char *) addr;
 347         return (tmp[nr >> 3] >> (nr & 7)) & 1;
 348 }
 349
 350 #define __set_le_bit(nr, addr) \
 351         __set_bit((nr) ^ BITOP_LE_SWIZZLE, (addr))
 352 #define __clear_le_bit(nr, addr) \
 353         __clear_bit((nr) ^ BITOP_LE_SWIZZLE, (addr))
 354
 355 #define test_and_set_le_bit(nr, addr) \
 356         test_and_set_bit((nr) ^ BITOP_LE_SWIZZLE, (addr))
 357 #define test_and_clear_le_bit(nr, addr) \
 358         test_and_clear_bit((nr) ^ BITOP_LE_SWIZZLE, (addr))
 359
 360 #define __test_and_set_le_bit(nr, addr) \
 361         __test_and_set_bit((nr) ^ BITOP_LE_SWIZZLE, (addr))
 362 #define __test_and_clear_le_bit(nr, addr) \
 363         __test_and_clear_bit((nr) ^ BITOP_LE_SWIZZLE, (addr))
 364
 365 #define find_first_zero_le_bit(addr, size) generic_find_next_zero_le_bit((addr), (size), 0)
 366 unsigned long generic_find_next_zero_le_bit(const unsigned long *addr,
 367                                     unsigned long size, unsigned long offset);
 368
 369 unsigned long generic_find_next_le_bit(const unsigned long *addr,
 370                                     unsigned long size, unsigned long offset);
 371 /* Bitmap functions for the ext2 filesystem */
 372
 373 #define ext2_set_bit(nr,addr) \
 374         __test_and_set_le_bit((nr), (unsigned long*)addr)
 375 #define ext2_clear_bit(nr, addr) \
 376         __test_and_clear_le_bit((nr), (unsigned long*)addr)
 377
 378 #define ext2_set_bit_atomic(lock, nr, addr) \
 379         test_and_set_le_bit((nr), (unsigned long*)addr)
 380 #define ext2_clear_bit_atomic(lock, nr, addr) \
 381         test_and_clear_le_bit((nr), (unsigned long*)addr)
 382
 383 #define ext2_test_bit(nr, addr)      test_le_bit((nr),(unsigned long*)addr)
 384
 385 #define ext2_find_first_zero_bit(addr, size) \
 386         find_first_zero_le_bit((unsigned long*)addr, size)
 387 #define ext2_find_next_zero_bit(addr, size, off) \
 388         generic_find_next_zero_le_bit((unsigned long*)addr, size, off)
 389
 390 #define ext2_find_next_bit(addr, size, off) \
 391         generic_find_next_le_bit((unsigned long *)addr, size, off)
 392 /* Bitmap functions for the minix filesystem.  */
 393
 394 #define minix_test_and_set_bit(nr,addr) \
 395         __test_and_set_le_bit(nr, (unsigned long *)addr)
 396 #define minix_set_bit(nr,addr) \
 397         __set_le_bit(nr, (unsigned long *)addr)
 398 #define minix_test_and_clear_bit(nr,addr) \
 399         __test_and_clear_le_bit(nr, (unsigned long *)addr)
 400 #define minix_test_bit(nr,addr) \
 401         test_le_bit(nr, (unsigned long *)addr)
 402
 403 #define minix_find_first_zero_bit(addr,size) \
 404         find_first_zero_le_bit((unsigned long *)addr, size)
 405
 406 #include <asm-generic/bitops/sched.h>
 407
 408 #endif /* __KERNEL__ */
 409
 410 #endif /* _ASM_POWERPC_BITOPS_H */