include/asm-mips/system.h

   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) 1994, 95, 96, 97, 98, 99, 2003 by Ralf Baechle
   7  * Copyright (C) 1996 by Paul M. Antoine
   8  * Copyright (C) 1999 Silicon Graphics
   9  * Kevin D. Kissell, kevink@mips.org and Carsten Langgaard, carstenl@mips.com
  10  * Copyright (C) 2000 MIPS Technologies, Inc.
  11  */
  12 #ifndef _ASM_SYSTEM_H
  13 #define _ASM_SYSTEM_H
  14
  15 #include <linux/config.h>
  16 #include <linux/types.h>
  17
  18 #include <asm/addrspace.h>
  19 #include <asm/cpu-features.h>
  20 #include <asm/ptrace.h>
  21 #include <asm/war.h>
  22 #include <asm/interrupt.h>
  23
  24 /*
  25  * read_barrier_depends - Flush all pending reads that subsequents reads
  26  * depend on.
  27  *
  28  * No data-dependent reads from memory-like regions are ever reordered
  29  * over this barrier.  All reads preceding this primitive are guaranteed
  30  * to access memory (but not necessarily other CPUs' caches) before any
  31  * reads following this primitive that depend on the data return by
  32  * any of the preceding reads.  This primitive is much lighter weight than
  33  * rmb() on most CPUs, and is never heavier weight than is
  34  * rmb().
  35  *
  36  * These ordering constraints are respected by both the local CPU
  37  * and the compiler.
  38  *
  39  * Ordering is not guaranteed by anything other than these primitives,
  40  * not even by data dependencies.  See the documentation for
  41  * memory_barrier() for examples and URLs to more information.
  42  *
  43  * For example, the following code would force ordering (the initial
  44  * value of "a" is zero, "b" is one, and "p" is "&a"):
  45  *
  46  * <programlisting>
  47  *      CPU 0                           CPU 1
  48  *
  49  *      b = 2;
  50  *      memory_barrier();
  51  *      p = &b;                         q = p;
  52  *                                      read_barrier_depends();
  53  *                                      d = *q;
  54  * </programlisting>
  55  *
  56  * because the read of "*q" depends on the read of "p" and these
  57  * two reads are separated by a read_barrier_depends().  However,
  58  * the following code, with the same initial values for "a" and "b":
  59  *
  60  * <programlisting>
  61  *      CPU 0                           CPU 1
  62  *
  63  *      a = 2;
  64  *      memory_barrier();
  65  *      b = 3;                          y = b;
  66  *                                      read_barrier_depends();
  67  *                                      x = a;
  68  * </programlisting>
  69  *
  70  * does not enforce ordering, since there is no data dependency between
  71  * the read of "a" and the read of "b".  Therefore, on some CPUs, such
  72  * as Alpha, "y" could be set to 3 and "x" to 0.  Use rmb()
  73  * in cases like thiswhere there are no data dependencies.
  74  */
  75
  76 #define read_barrier_depends()  do { } while(0)
  77
  78 #ifdef CONFIG_CPU_HAS_SYNC
  79 #define __sync()                                \
  80         __asm__ __volatile__(                   \
  81                 ".set   push\n\t"               \
  82                 ".set   noreorder\n\t"          \
  83                 ".set   mips2\n\t"              \
  84                 "sync\n\t"                      \
  85                 ".set   pop"                    \
  86                 : /* no output */               \
  87                 : /* no input */                \
  88                 : "memory")
  89 #else
  90 #define __sync()        do { } while(0)
  91 #endif
  92
  93 #define __fast_iob()                            \
  94         __asm__ __volatile__(                   \
  95                 ".set   push\n\t"               \
  96                 ".set   noreorder\n\t"          \
  97                 "lw     $0,%0\n\t"              \
  98                 "nop\n\t"                       \
  99                 ".set   pop"                    \
 100                 : /* no output */               \
 101                 : "m" (*(int *)CKSEG1)          \
 102                 : "memory")
 103
 104 #define fast_wmb()      __sync()
 105 #define fast_rmb()      __sync()
 106 #define fast_mb()       __sync()
 107 #define fast_iob()                              \
 108         do {                                    \
 109                 __sync();                       \
 110                 __fast_iob();                   \
 111         } while (0)
 112
 113 #ifdef CONFIG_CPU_HAS_WB
 114
 115 #include <asm/wbflush.h>
 116
 117 #define wmb()           fast_wmb()
 118 #define rmb()           fast_rmb()
 119 #define mb()            wbflush()
 120 #define iob()           wbflush()
 121
 122 #else /* !CONFIG_CPU_HAS_WB */
 123
 124 #define wmb()           fast_wmb()
 125 #define rmb()           fast_rmb()
 126 #define mb()            fast_mb()
 127 #define iob()           fast_iob()
 128
 129 #endif /* !CONFIG_CPU_HAS_WB */
 130
 131 #ifdef CONFIG_SMP
 132 #define smp_mb()        mb()
 133 #define smp_rmb()       rmb()
 134 #define smp_wmb()       wmb()
 135 #define smp_read_barrier_depends()      read_barrier_depends()
 136 #else
 137 #define smp_mb()        barrier()
 138 #define smp_rmb()       barrier()
 139 #define smp_wmb()       barrier()
 140 #define smp_read_barrier_depends()      do { } while(0)
 141 #endif
 142
 143 #define set_mb(var, value) \
 144 do { var = value; mb(); } while (0)
 145
 146 #define set_wmb(var, value) \
 147 do { var = value; wmb(); } while (0)
 148
 149 /*
 150  * switch_to(n) should switch tasks to task nr n, first
 151  * checking that n isn't the current task, in which case it does nothing.
 152  */
 153 extern asmlinkage void *resume(void *last, void *next, void *next_ti);
 154
 155 struct task_struct;
 156
 157 #define switch_to(prev,next,last) \
 158 do { \
 159         (last) = resume(prev, next, next->thread_info); \
 160 } while(0)
 161
 162 #define ROT_IN_PIECES                                                   \
 163         "       .set    noreorder       \n"                             \
 164         "       .set    reorder         \n"
 165
 166 static inline unsigned long __xchg_u32(volatile int * m, unsigned int val)
 167 {
 168         __u32 retval;
 169
 170         if (cpu_has_llsc && R10000_LLSC_WAR) {
 171                 unsigned long dummy;
 172
 173                 __asm__ __volatile__(
 174                 "1:     ll      %0, %3                  # xchg_u32      \n"
 175                 "       move    %2, %z4                                 \n"
 176                 "       sc      %2, %1                                  \n"
 177                 "       beqzl   %2, 1b                                  \n"
 178                 ROT_IN_PIECES
 179 #ifdef CONFIG_SMP
 180                 "       sync                                            \n"
 181 #endif
 182                 : "=&r" (retval), "=m" (*m), "=&r" (dummy)
 183                 : "R" (*m), "Jr" (val)
 184                 : "memory");
 185         } else if (cpu_has_llsc) {
 186                 unsigned long dummy;
 187
 188                 __asm__ __volatile__(
 189                 "1:     ll      %0, %3                  # xchg_u32      \n"
 190                 "       move    %2, %z4                                 \n"
 191                 "       sc      %2, %1                                  \n"
 192                 "       beqz    %2, 1b                                  \n"
 193 #ifdef CONFIG_SMP
 194                 "       sync                                            \n"
 195 #endif
 196                 : "=&r" (retval), "=m" (*m), "=&r" (dummy)
 197                 : "R" (*m), "Jr" (val)
 198                 : "memory");
 199         } else {
 200                 unsigned long flags;
 201
 202                 local_irq_save(flags);
 203                 retval = *m;
 204                 *m = val;
 205                 local_irq_restore(flags);       /* implies memory barrier  */
 206         }
 207
 208         return retval;
 209 }
 210
 211 #ifdef CONFIG_MIPS64
 212 static inline __u64 __xchg_u64(volatile __u64 * m, __u64 val)
 213 {
 214         __u64 retval;
 215
 216         if (cpu_has_llsc && R10000_LLSC_WAR) {
 217                 unsigned long dummy;
 218
 219                 __asm__ __volatile__(
 220                 "1:     lld     %0, %3                  # xchg_u64      \n"
 221                 "       move    %2, %z4                                 \n"
 222                 "       scd     %2, %1                                  \n"
 223                 "       beqzl   %2, 1b                                  \n"
 224                 ROT_IN_PIECES
 225 #ifdef CONFIG_SMP
 226                 "       sync                                            \n"
 227 #endif
 228                 : "=&r" (retval), "=m" (*m), "=&r" (dummy)
 229                 : "R" (*m), "Jr" (val)
 230                 : "memory");
 231         } else if (cpu_has_llsc) {
 232                 unsigned long dummy;
 233
 234                 __asm__ __volatile__(
 235                 "1:     lld     %0, %3                  # xchg_u64      \n"
 236                 "       move    %2, %z4                                 \n"
 237                 "       scd     %2, %1                                  \n"
 238                 "       beqz    %2, 1b                                  \n"
 239 #ifdef CONFIG_SMP
 240                 "       sync                                            \n"
 241 #endif
 242                 : "=&r" (retval), "=m" (*m), "=&r" (dummy)
 243                 : "R" (*m), "Jr" (val)
 244                 : "memory");
 245         } else {
 246                 unsigned long flags;
 247
 248                 local_irq_save(flags);
 249                 retval = *m;
 250                 *m = val;
 251                 local_irq_restore(flags);       /* implies memory barrier  */
 252         }
 253
 254         return retval;
 255 }
 256 #else
 257 extern __u64 __xchg_u64_unsupported_on_32bit_kernels(volatile __u64 * m, __u64 val);
 258 #define __xchg_u64 __xchg_u64_unsupported_on_32bit_kernels
 259 #endif
 260
 261 /* This function doesn't exist, so you'll get a linker error
 262    if something tries to do an invalid xchg().  */
 263 extern void __xchg_called_with_bad_pointer(void);
 264
 265 static inline unsigned long __xchg(unsigned long x, volatile void * ptr, int size)
 266 {
 267         switch (size) {
 268                 case 4:
 269                         return __xchg_u32(ptr, x);
 270                 case 8:
 271                         return __xchg_u64(ptr, x);
 272         }
 273         __xchg_called_with_bad_pointer();
 274         return x;
 275 }
 276
 277 #define xchg(ptr,x) ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))
 278 #define tas(ptr) (xchg((ptr),1))
 279
 280 #define __HAVE_ARCH_CMPXCHG 1
 281
 282 static inline unsigned long __cmpxchg_u32(volatile int * m, unsigned long old,
 283         unsigned long new)
 284 {
 285         __u32 retval;
 286
 287         if (cpu_has_llsc && R10000_LLSC_WAR) {
 288                 __asm__ __volatile__(
 289                 "       .set    noat                                    \n"
 290                 "1:     ll      %0, %2                  # __cmpxchg_u32 \n"
 291                 "       bne     %0, %z3, 2f                             \n"
 292                 "       move    $1, %z4                                 \n"
 293                 "       sc      $1, %1                                  \n"
 294                 "       beqzl   $1, 1b                                  \n"
 295                 ROT_IN_PIECES
 296 #ifdef CONFIG_SMP
 297                 "       sync                                            \n"
 298 #endif
 299                 "2:                                                     \n"
 300                 "       .set    at                                      \n"
 301                 : "=&r" (retval), "=m" (*m)
 302                 : "R" (*m), "Jr" (old), "Jr" (new)
 303                 : "memory");
 304         } else if (cpu_has_llsc) {
 305                 __asm__ __volatile__(
 306                 "       .set    noat                                    \n"
 307                 "1:     ll      %0, %2                  # __cmpxchg_u32 \n"
 308                 "       bne     %0, %z3, 2f                             \n"
 309                 "       move    $1, %z4                                 \n"
 310                 "       sc      $1, %1                                  \n"
 311                 "       beqz    $1, 1b                                  \n"
 312 #ifdef CONFIG_SMP
 313                 "       sync                                            \n"
 314 #endif
 315                 "2:                                                     \n"
 316                 "       .set    at                                      \n"
 317                 : "=&r" (retval), "=m" (*m)
 318                 : "R" (*m), "Jr" (old), "Jr" (new)
 319                 : "memory");
 320         } else {
 321                 unsigned long flags;
 322
 323                 local_irq_save(flags);
 324                 retval = *m;
 325                 if (retval == old)
 326                         *m = new;
 327                 local_irq_restore(flags);       /* implies memory barrier  */
 328         }
 329
 330         return retval;
 331 }
 332
 333 #ifdef CONFIG_MIPS64
 334 static inline unsigned long __cmpxchg_u64(volatile int * m, unsigned long old,
 335         unsigned long new)
 336 {
 337         __u64 retval;
 338
 339         if (cpu_has_llsc) {
 340                 __asm__ __volatile__(
 341                 "       .set    noat                                    \n"
 342                 "1:     lld     %0, %2                  # __cmpxchg_u64 \n"
 343                 "       bne     %0, %z3, 2f                             \n"
 344                 "       move    $1, %z4                                 \n"
 345                 "       scd     $1, %1                                  \n"
 346                 "       beqzl   $1, 1b                                  \n"
 347                 ROT_IN_PIECES
 348 #ifdef CONFIG_SMP
 349                 "       sync                                            \n"
 350 #endif
 351                 "2:                                                     \n"
 352                 "       .set    at                                      \n"
 353                 : "=&r" (retval), "=m" (*m)
 354                 : "R" (*m), "Jr" (old), "Jr" (new)
 355                 : "memory");
 356         } else if (cpu_has_llsc) {
 357                 __asm__ __volatile__(
 358                 "       .set    noat                                    \n"
 359                 "1:     lld     %0, %2                  # __cmpxchg_u64 \n"
 360                 "       bne     %0, %z3, 2f                             \n"
 361                 "       move    $1, %z4                                 \n"
 362                 "       scd     $1, %1                                  \n"
 363                 "       beqz    $1, 1b                                  \n"
 364 #ifdef CONFIG_SMP
 365                 "       sync                                            \n"
 366 #endif
 367                 "2:                                                     \n"
 368                 "       .set    at                                      \n"
 369                 : "=&r" (retval), "=m" (*m)
 370                 : "R" (*m), "Jr" (old), "Jr" (new)
 371                 : "memory");
 372         } else {
 373                 unsigned long flags;
 374
 375                 local_irq_save(flags);
 376                 retval = *m;
 377                 if (retval == old)
 378                         *m = new;
 379                 local_irq_restore(flags);       /* implies memory barrier  */
 380         }
 381
 382         return retval;
 383 }
 384 #else
 385 extern unsigned long __cmpxchg_u64_unsupported_on_32bit_kernels(
 386         volatile int * m, unsigned long old, unsigned long new);
 387 #define __cmpxchg_u64 __cmpxchg_u64_unsupported_on_32bit_kernels
 388 #endif
 389
 390 /* This function doesn't exist, so you'll get a linker error
 391    if something tries to do an invalid cmpxchg().  */
 392 extern void __cmpxchg_called_with_bad_pointer(void);
 393
 394 static inline unsigned long __cmpxchg(volatile void * ptr, unsigned long old,
 395         unsigned long new, int size)
 396 {
 397         switch (size) {
 398         case 4:
 399                 return __cmpxchg_u32(ptr, old, new);
 400         case 8:
 401                 return __cmpxchg_u64(ptr, old, new);
 402         }
 403         __cmpxchg_called_with_bad_pointer();
 404         return old;
 405 }
 406
 407 #define cmpxchg(ptr,old,new) ((__typeof__(*(ptr)))__cmpxchg((ptr), (unsigned long)(old), (unsigned long)(new),sizeof(*(ptr))))
 408
 409 extern void *set_except_vector(int n, void *addr);
 410 extern void per_cpu_trap_init(void);
 411
 412 extern NORET_TYPE void __die(const char *, struct pt_regs *, const char *file,
 413         const char *func, unsigned long line);
 414 extern void __die_if_kernel(const char *, struct pt_regs *, const char *file,
 415         const char *func, unsigned long line);
 416
 417 #define die(msg, regs)                                                  \
 418         __die(msg, regs, __FILE__ ":", __FUNCTION__, __LINE__)
 419 #define die_if_kernel(msg, regs)                                        \
 420         __die_if_kernel(msg, regs, __FILE__ ":", __FUNCTION__, __LINE__)
 421
 422 extern int stop_a_enabled;
 423
 424 /*
 425  * Taken from include/asm-ia64/system.h; prevents deadlock on SMP
 426  * systems.
 427  */
 428 #define prepare_arch_switch(rq, next)           \
 429 do {                                            \
 430         spin_lock(&(next)->switch_lock);        \
 431         spin_unlock(&(rq)->lock);               \
 432 } while (0)
 433 #define finish_arch_switch(rq, prev)    spin_unlock_irq(&(prev)->switch_lock)
 434 #define task_running(rq, p)             ((rq)->curr == (p) || spin_is_locked(&(p)->switch_lock))
 435
 436 #define arch_align_stack(x) (x)
 437
 438 #endif /* _ASM_SYSTEM_H */