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/types.h>
  16
  17 #include <asm/addrspace.h>
  18 #include <asm/cpu-features.h>
  19 #include <asm/dsp.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 this where 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 #ifdef CONFIG_MIPS_MT_FPAFF
 158
 159 /*
 160  * Handle the scheduler resume end of FPU affinity management.  We do this
 161  * inline to try to keep the overhead down. If we have been forced to run on
 162  * a "CPU" with an FPU because of a previous high level of FP computation,
 163  * but did not actually use the FPU during the most recent time-slice (CU1
 164  * isn't set), we undo the restriction on cpus_allowed.
 165  *
 166  * We're not calling set_cpus_allowed() here, because we have no need to
 167  * force prompt migration - we're already switching the current CPU to a
 168  * different thread.
 169  */
 170
 171 #define switch_to(prev,next,last)                                       \
 172 do {                                                                    \
 173         if (cpu_has_fpu &&                                              \
 174             (prev->thread.mflags & MF_FPUBOUND) &&                      \
 175              (!(KSTK_STATUS(prev) & ST0_CU1))) {                        \
 176                 prev->thread.mflags &= ~MF_FPUBOUND;                    \
 177                 prev->cpus_allowed = prev->thread.user_cpus_allowed;    \
 178         }                                                               \
 179         if (cpu_has_dsp)                                                \
 180                 __save_dsp(prev);                                       \
 181         next->thread.emulated_fp = 0;                                   \
 182         (last) = resume(prev, next, next->thread_info);                 \
 183         if (cpu_has_dsp)                                                \
 184                 __restore_dsp(current);                                 \
 185 } while(0)
 186
 187 #else
 188 #define switch_to(prev,next,last)                                       \
 189 do {                                                                    \
 190         if (cpu_has_dsp)                                                \
 191                 __save_dsp(prev);                                       \
 192         (last) = resume(prev, next, task_thread_info(next));            \
 193         if (cpu_has_dsp)                                                \
 194                 __restore_dsp(current);                                 \
 195 } while(0)
 196 #endif
 197
 198 /*
 199  * On SMP systems, when the scheduler does migration-cost autodetection,
 200  * it needs a way to flush as much of the CPU's caches as possible.
 201  *
 202  * TODO: fill this in!
 203  */
 204 static inline void sched_cacheflush(void)
 205 {
 206 }
 207
 208 static inline unsigned long __xchg_u32(volatile int * m, unsigned int val)
 209 {
 210         __u32 retval;
 211
 212         if (cpu_has_llsc && R10000_LLSC_WAR) {
 213                 unsigned long dummy;
 214
 215                 __asm__ __volatile__(
 216                 "       .set    mips3                                   \n"
 217                 "1:     ll      %0, %3                  # xchg_u32      \n"
 218                 "       .set    mips0                                   \n"
 219                 "       move    %2, %z4                                 \n"
 220                 "       .set    mips3                                   \n"
 221                 "       sc      %2, %1                                  \n"
 222                 "       beqzl   %2, 1b                                  \n"
 223 #ifdef CONFIG_SMP
 224                 "       sync                                            \n"
 225 #endif
 226                 "       .set    mips0                                   \n"
 227                 : "=&r" (retval), "=m" (*m), "=&r" (dummy)
 228                 : "R" (*m), "Jr" (val)
 229                 : "memory");
 230         } else if (cpu_has_llsc) {
 231                 unsigned long dummy;
 232
 233                 __asm__ __volatile__(
 234                 "       .set    mips3                                   \n"
 235                 "1:     ll      %0, %3                  # xchg_u32      \n"
 236                 "       .set    mips0                                   \n"
 237                 "       move    %2, %z4                                 \n"
 238                 "       .set    mips3                                   \n"
 239                 "       sc      %2, %1                                  \n"
 240                 "       beqz    %2, 1b                                  \n"
 241 #ifdef CONFIG_SMP
 242                 "       sync                                            \n"
 243 #endif
 244                 "       .set    mips0                                   \n"
 245                 : "=&r" (retval), "=m" (*m), "=&r" (dummy)
 246                 : "R" (*m), "Jr" (val)
 247                 : "memory");
 248         } else {
 249                 unsigned long flags;
 250
 251                 local_irq_save(flags);
 252                 retval = *m;
 253                 *m = val;
 254                 local_irq_restore(flags);       /* implies memory barrier  */
 255         }
 256
 257         return retval;
 258 }
 259
 260 #ifdef CONFIG_64BIT
 261 static inline __u64 __xchg_u64(volatile __u64 * m, __u64 val)
 262 {
 263         __u64 retval;
 264
 265         if (cpu_has_llsc && R10000_LLSC_WAR) {
 266                 unsigned long dummy;
 267
 268                 __asm__ __volatile__(
 269                 "       .set    mips3                                   \n"
 270                 "1:     lld     %0, %3                  # xchg_u64      \n"
 271                 "       move    %2, %z4                                 \n"
 272                 "       scd     %2, %1                                  \n"
 273                 "       beqzl   %2, 1b                                  \n"
 274 #ifdef CONFIG_SMP
 275                 "       sync                                            \n"
 276 #endif
 277                 "       .set    mips0                                   \n"
 278                 : "=&r" (retval), "=m" (*m), "=&r" (dummy)
 279                 : "R" (*m), "Jr" (val)
 280                 : "memory");
 281         } else if (cpu_has_llsc) {
 282                 unsigned long dummy;
 283
 284                 __asm__ __volatile__(
 285                 "       .set    mips3                                   \n"
 286                 "1:     lld     %0, %3                  # xchg_u64      \n"
 287                 "       move    %2, %z4                                 \n"
 288                 "       scd     %2, %1                                  \n"
 289                 "       beqz    %2, 1b                                  \n"
 290 #ifdef CONFIG_SMP
 291                 "       sync                                            \n"
 292 #endif
 293                 "       .set    mips0                                   \n"
 294                 : "=&r" (retval), "=m" (*m), "=&r" (dummy)
 295                 : "R" (*m), "Jr" (val)
 296                 : "memory");
 297         } else {
 298                 unsigned long flags;
 299
 300                 local_irq_save(flags);
 301                 retval = *m;
 302                 *m = val;
 303                 local_irq_restore(flags);       /* implies memory barrier  */
 304         }
 305
 306         return retval;
 307 }
 308 #else
 309 extern __u64 __xchg_u64_unsupported_on_32bit_kernels(volatile __u64 * m, __u64 val);
 310 #define __xchg_u64 __xchg_u64_unsupported_on_32bit_kernels
 311 #endif
 312
 313 /* This function doesn't exist, so you'll get a linker error
 314    if something tries to do an invalid xchg().  */
 315 extern void __xchg_called_with_bad_pointer(void);
 316
 317 static inline unsigned long __xchg(unsigned long x, volatile void * ptr, int size)
 318 {
 319         switch (size) {
 320         case 4:
 321                 return __xchg_u32(ptr, x);
 322         case 8:
 323                 return __xchg_u64(ptr, x);
 324         }
 325         __xchg_called_with_bad_pointer();
 326         return x;
 327 }
 328
 329 #define xchg(ptr,x) ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))
 330 #define tas(ptr) (xchg((ptr),1))
 331
 332 #define __HAVE_ARCH_CMPXCHG 1
 333
 334 static inline unsigned long __cmpxchg_u32(volatile int * m, unsigned long old,
 335         unsigned long new)
 336 {
 337         __u32 retval;
 338
 339         if (cpu_has_llsc && R10000_LLSC_WAR) {
 340                 __asm__ __volatile__(
 341                 "       .set    push                                    \n"
 342                 "       .set    noat                                    \n"
 343                 "       .set    mips3                                   \n"
 344                 "1:     ll      %0, %2                  # __cmpxchg_u32 \n"
 345                 "       bne     %0, %z3, 2f                             \n"
 346                 "       .set    mips0                                   \n"
 347                 "       move    $1, %z4                                 \n"
 348                 "       .set    mips3                                   \n"
 349                 "       sc      $1, %1                                  \n"
 350                 "       beqzl   $1, 1b                                  \n"
 351 #ifdef CONFIG_SMP
 352                 "       sync                                            \n"
 353 #endif
 354                 "2:                                                     \n"
 355                 "       .set    pop                                     \n"
 356                 : "=&r" (retval), "=R" (*m)
 357                 : "R" (*m), "Jr" (old), "Jr" (new)
 358                 : "memory");
 359         } else if (cpu_has_llsc) {
 360                 __asm__ __volatile__(
 361                 "       .set    push                                    \n"
 362                 "       .set    noat                                    \n"
 363                 "       .set    mips3                                   \n"
 364                 "1:     ll      %0, %2                  # __cmpxchg_u32 \n"
 365                 "       bne     %0, %z3, 2f                             \n"
 366                 "       .set    mips0                                   \n"
 367                 "       move    $1, %z4                                 \n"
 368                 "       .set    mips3                                   \n"
 369                 "       sc      $1, %1                                  \n"
 370                 "       beqz    $1, 1b                                  \n"
 371 #ifdef CONFIG_SMP
 372                 "       sync                                            \n"
 373 #endif
 374                 "2:                                                     \n"
 375                 "       .set    pop                                     \n"
 376                 : "=&r" (retval), "=R" (*m)
 377                 : "R" (*m), "Jr" (old), "Jr" (new)
 378                 : "memory");
 379         } else {
 380                 unsigned long flags;
 381
 382                 local_irq_save(flags);
 383                 retval = *m;
 384                 if (retval == old)
 385                         *m = new;
 386                 local_irq_restore(flags);       /* implies memory barrier  */
 387         }
 388
 389         return retval;
 390 }
 391
 392 #ifdef CONFIG_64BIT
 393 static inline unsigned long __cmpxchg_u64(volatile int * m, unsigned long old,
 394         unsigned long new)
 395 {
 396         __u64 retval;
 397
 398         if (cpu_has_llsc) {
 399                 __asm__ __volatile__(
 400                 "       .set    push                                    \n"
 401                 "       .set    noat                                    \n"
 402                 "       .set    mips3                                   \n"
 403                 "1:     lld     %0, %2                  # __cmpxchg_u64 \n"
 404                 "       bne     %0, %z3, 2f                             \n"
 405                 "       move    $1, %z4                                 \n"
 406                 "       scd     $1, %1                                  \n"
 407                 "       beqzl   $1, 1b                                  \n"
 408 #ifdef CONFIG_SMP
 409                 "       sync                                            \n"
 410 #endif
 411                 "2:                                                     \n"
 412                 "       .set    pop                                     \n"
 413                 : "=&r" (retval), "=R" (*m)
 414                 : "R" (*m), "Jr" (old), "Jr" (new)
 415                 : "memory");
 416         } else if (cpu_has_llsc) {
 417                 __asm__ __volatile__(
 418                 "       .set    push                                    \n"
 419                 "       .set    noat                                    \n"
 420                 "       .set    mips3                                   \n"
 421                 "1:     lld     %0, %2                  # __cmpxchg_u64 \n"
 422                 "       bne     %0, %z3, 2f                             \n"
 423                 "       move    $1, %z4                                 \n"
 424                 "       scd     $1, %1                                  \n"
 425                 "       beqz    $1, 1b                                  \n"
 426 #ifdef CONFIG_SMP
 427                 "       sync                                            \n"
 428 #endif
 429                 "2:                                                     \n"
 430                 "       .set    pop                                     \n"
 431                 : "=&r" (retval), "=R" (*m)
 432                 : "R" (*m), "Jr" (old), "Jr" (new)
 433                 : "memory");
 434         } else {
 435                 unsigned long flags;
 436
 437                 local_irq_save(flags);
 438                 retval = *m;
 439                 if (retval == old)
 440                         *m = new;
 441                 local_irq_restore(flags);       /* implies memory barrier  */
 442         }
 443
 444         return retval;
 445 }
 446 #else
 447 extern unsigned long __cmpxchg_u64_unsupported_on_32bit_kernels(
 448         volatile int * m, unsigned long old, unsigned long new);
 449 #define __cmpxchg_u64 __cmpxchg_u64_unsupported_on_32bit_kernels
 450 #endif
 451
 452 /* This function doesn't exist, so you'll get a linker error
 453    if something tries to do an invalid cmpxchg().  */
 454 extern void __cmpxchg_called_with_bad_pointer(void);
 455
 456 static inline unsigned long __cmpxchg(volatile void * ptr, unsigned long old,
 457         unsigned long new, int size)
 458 {
 459         switch (size) {
 460         case 4:
 461                 return __cmpxchg_u32(ptr, old, new);
 462         case 8:
 463                 return __cmpxchg_u64(ptr, old, new);
 464         }
 465         __cmpxchg_called_with_bad_pointer();
 466         return old;
 467 }
 468
 469 #define cmpxchg(ptr,old,new) ((__typeof__(*(ptr)))__cmpxchg((ptr), (unsigned long)(old), (unsigned long)(new),sizeof(*(ptr))))
 470
 471 extern void set_handler (unsigned long offset, void *addr, unsigned long len);
 472 extern void set_uncached_handler (unsigned long offset, void *addr, unsigned long len);
 473 extern void *set_vi_handler (int n, void *addr);
 474 extern void *set_except_vector(int n, void *addr);
 475 extern unsigned long ebase;
 476 extern void per_cpu_trap_init(void);
 477
 478 extern NORET_TYPE void die(const char *, struct pt_regs *);
 479
 480 static inline void die_if_kernel(const char *str, struct pt_regs *regs)
 481 {
 482         if (unlikely(!user_mode(regs)))
 483                 die(str, regs);
 484 }
 485
 486 extern int stop_a_enabled;
 487
 488 /*
 489  * See include/asm-ia64/system.h; prevents deadlock on SMP
 490  * systems.
 491  */
 492 #define __ARCH_WANT_UNLOCKED_CTXSW
 493
 494 #define arch_align_stack(x) (x)
 495
 496 #endif /* _ASM_SYSTEM_H */