arch/mips/include/asm/hazards.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) 2003, 04, 07 Ralf Baechle <ralf@linux-mips.org>
   7  * Copyright (C) MIPS Technologies, Inc.
   8  *   written by Ralf Baechle <ralf@linux-mips.org>
   9  */
  10 #ifndef _ASM_HAZARDS_H
  11 #define _ASM_HAZARDS_H
  12
  13 #include <linux/stringify.h>
  14
  15 #define ___ssnop                                                        \
  16         sll     $0, $0, 1
  17
  18 #define ___ehb                                                          \
  19         sll     $0, $0, 3
  20
  21 /*
  22  * TLB hazards
  23  */
  24 #if defined(CONFIG_CPU_MIPSR2) && !defined(CONFIG_CPU_CAVIUM_OCTEON)
  25
  26 /*
  27  * MIPSR2 defines ehb for hazard avoidance
  28  */
  29
  30 #define __mtc0_tlbw_hazard                                              \
  31         ___ehb
  32
  33 #define __tlbw_use_hazard                                               \
  34         ___ehb
  35
  36 #define __tlb_probe_hazard                                              \
  37         ___ehb
  38
  39 #define __irq_enable_hazard                                             \
  40         ___ehb
  41
  42 #define __irq_disable_hazard                                            \
  43         ___ehb
  44
  45 #define __back_to_back_c0_hazard                                        \
  46         ___ehb
  47
  48 /*
  49  * gcc has a tradition of misscompiling the previous construct using the
  50  * address of a label as argument to inline assembler.  Gas otoh has the
  51  * annoying difference between la and dla which are only usable for 32-bit
  52  * rsp. 64-bit code, so can't be used without conditional compilation.
  53  * The alterantive is switching the assembler to 64-bit code which happens
  54  * to work right even for 32-bit code ...
  55  */
  56 #define instruction_hazard()                                            \
  57 do {                                                                    \
  58         unsigned long tmp;                                              \
  59                                                                         \
  60         __asm__ __volatile__(                                           \
  61         "       .set    mips64r2                                \n"     \
  62         "       dla     %0, 1f                                  \n"     \
  63         "       jr.hb   %0                                      \n"     \
  64         "       .set    mips0                                   \n"     \
  65         "1:                                                     \n"     \
  66         : "=r" (tmp));                                                  \
  67 } while (0)
  68
  69 #elif (defined(CONFIG_CPU_MIPSR1) && !defined(CONFIG_MIPS_ALCHEMY)) || \
  70         defined(CONFIG_CPU_BMIPS)
  71
  72 /*
  73  * These are slightly complicated by the fact that we guarantee R1 kernels to
  74  * run fine on R2 processors.
  75  */
  76
  77 #define __mtc0_tlbw_hazard                                              \
  78         ___ssnop;                                                       \
  79         ___ssnop;                                                       \
  80         ___ehb
  81
  82 #define __tlbw_use_hazard                                               \
  83         ___ssnop;                                                       \
  84         ___ssnop;                                                       \
  85         ___ssnop;                                                       \
  86         ___ehb
  87
  88 #define __tlb_probe_hazard                                              \
  89         ___ssnop;                                                       \
  90         ___ssnop;                                                       \
  91         ___ssnop;                                                       \
  92         ___ehb
  93
  94 #define __irq_enable_hazard                                             \
  95         ___ssnop;                                                       \
  96         ___ssnop;                                                       \
  97         ___ssnop;                                                       \
  98         ___ehb
  99
 100 #define __irq_disable_hazard                                            \
 101         ___ssnop;                                                       \
 102         ___ssnop;                                                       \
 103         ___ssnop;                                                       \
 104         ___ehb
 105
 106 #define __back_to_back_c0_hazard                                        \
 107         ___ssnop;                                                       \
 108         ___ssnop;                                                       \
 109         ___ssnop;                                                       \
 110         ___ehb
 111
 112 /*
 113  * gcc has a tradition of misscompiling the previous construct using the
 114  * address of a label as argument to inline assembler.  Gas otoh has the
 115  * annoying difference between la and dla which are only usable for 32-bit
 116  * rsp. 64-bit code, so can't be used without conditional compilation.
 117  * The alterantive is switching the assembler to 64-bit code which happens
 118  * to work right even for 32-bit code ...
 119  */
 120 #define __instruction_hazard()                                          \
 121 do {                                                                    \
 122         unsigned long tmp;                                              \
 123                                                                         \
 124         __asm__ __volatile__(                                           \
 125         "       .set    mips64r2                                \n"     \
 126         "       dla     %0, 1f                                  \n"     \
 127         "       jr.hb   %0                                      \n"     \
 128         "       .set    mips0                                   \n"     \
 129         "1:                                                     \n"     \
 130         : "=r" (tmp));                                                  \
 131 } while (0)
 132
 133 #define instruction_hazard()                                            \
 134 do {                                                                    \
 135         if (cpu_has_mips_r2)                                            \
 136                 __instruction_hazard();                                 \
 137 } while (0)
 138
 139 #elif defined(CONFIG_MIPS_ALCHEMY) || defined(CONFIG_CPU_CAVIUM_OCTEON) || \
 140         defined(CONFIG_CPU_LOONGSON2) || defined(CONFIG_CPU_R10000) || \
 141         defined(CONFIG_CPU_R5500) || defined(CONFIG_CPU_XLR)
 142
 143 /*
 144  * R10000 rocks - all hazards handled in hardware, so this becomes a nobrainer.
 145  */
 146
 147 #define __mtc0_tlbw_hazard
 148
 149 #define __tlbw_use_hazard
 150
 151 #define __tlb_probe_hazard
 152
 153 #define __irq_enable_hazard
 154
 155 #define __irq_disable_hazard
 156
 157 #define __back_to_back_c0_hazard
 158
 159 #define instruction_hazard() do { } while (0)
 160
 161 #elif defined(CONFIG_CPU_SB1)
 162
 163 /*
 164  * Mostly like R4000 for historic reasons
 165  */
 166 #define __mtc0_tlbw_hazard
 167
 168 #define __tlbw_use_hazard
 169
 170 #define __tlb_probe_hazard
 171
 172 #define __irq_enable_hazard
 173
 174 #define __irq_disable_hazard                                            \
 175         ___ssnop;                                                       \
 176         ___ssnop;                                                       \
 177         ___ssnop
 178
 179 #define __back_to_back_c0_hazard
 180
 181 #define instruction_hazard() do { } while (0)
 182
 183 #else
 184
 185 /*
 186  * Finally the catchall case for all other processors including R4000, R4400,
 187  * R4600, R4700, R5000, RM7000, NEC VR41xx etc.
 188  *
 189  * The taken branch will result in a two cycle penalty for the two killed
 190  * instructions on R4000 / R4400.  Other processors only have a single cycle
 191  * hazard so this is nice trick to have an optimal code for a range of
 192  * processors.
 193  */
 194 #define __mtc0_tlbw_hazard                                              \
 195         nop;                                                            \
 196         nop
 197
 198 #define __tlbw_use_hazard                                               \
 199         nop;                                                            \
 200         nop;                                                            \
 201         nop
 202
 203 #define __tlb_probe_hazard                                              \
 204         nop;                                                            \
 205         nop;                                                            \
 206         nop
 207
 208 #define __irq_enable_hazard                                             \
 209         ___ssnop;                                                       \
 210         ___ssnop;                                                       \
 211         ___ssnop
 212
 213 #define __irq_disable_hazard                                            \
 214         nop;                                                            \
 215         nop;                                                            \
 216         nop
 217
 218 #define __back_to_back_c0_hazard                                        \
 219         ___ssnop;                                                       \
 220         ___ssnop;                                                       \
 221         ___ssnop
 222
 223 #define instruction_hazard() do { } while (0)
 224
 225 #endif
 226
 227
 228 /* FPU hazards */
 229
 230 #if defined(CONFIG_CPU_SB1)
 231
 232 #define __enable_fpu_hazard                                             \
 233         .set    push;                                                   \
 234         .set    mips64;                                                 \
 235         .set    noreorder;                                              \
 236         ___ssnop;                                                       \
 237         bnezl   $0, .+4;                                                \
 238         ___ssnop;                                                       \
 239         .set    pop
 240
 241 #define __disable_fpu_hazard
 242
 243 #elif defined(CONFIG_CPU_MIPSR2)
 244
 245 #define __enable_fpu_hazard                                             \
 246         ___ehb
 247
 248 #define __disable_fpu_hazard                                            \
 249         ___ehb
 250
 251 #else
 252
 253 #define __enable_fpu_hazard                                             \
 254         nop;                                                            \
 255         nop;                                                            \
 256         nop;                                                            \
 257         nop
 258
 259 #define __disable_fpu_hazard                                            \
 260         ___ehb
 261
 262 #endif
 263
 264 #ifdef __ASSEMBLY__
 265
 266 #define _ssnop ___ssnop
 267 #define _ehb ___ehb
 268 #define mtc0_tlbw_hazard __mtc0_tlbw_hazard
 269 #define tlbw_use_hazard __tlbw_use_hazard
 270 #define tlb_probe_hazard __tlb_probe_hazard
 271 #define irq_enable_hazard __irq_enable_hazard
 272 #define irq_disable_hazard __irq_disable_hazard
 273 #define back_to_back_c0_hazard __back_to_back_c0_hazard
 274 #define enable_fpu_hazard __enable_fpu_hazard
 275 #define disable_fpu_hazard __disable_fpu_hazard
 276
 277 #else
 278
 279 #define _ssnop()                                                        \
 280 do {                                                                    \
 281         __asm__ __volatile__(                                           \
 282         __stringify(___ssnop)                                           \
 283         );                                                              \
 284 } while (0)
 285
 286 #define _ehb()                                                          \
 287 do {                                                                    \
 288         __asm__ __volatile__(                                           \
 289         __stringify(___ehb)                                             \
 290         );                                                              \
 291 } while (0)
 292
 293
 294 #define mtc0_tlbw_hazard()                                              \
 295 do {                                                                    \
 296         __asm__ __volatile__(                                           \
 297         __stringify(__mtc0_tlbw_hazard)                                 \
 298         );                                                              \
 299 } while (0)
 300
 301
 302 #define tlbw_use_hazard()                                               \
 303 do {                                                                    \
 304         __asm__ __volatile__(                                           \
 305         __stringify(__tlbw_use_hazard)                                  \
 306         );                                                              \
 307 } while (0)
 308
 309
 310 #define tlb_probe_hazard()                                              \
 311 do {                                                                    \
 312         __asm__ __volatile__(                                           \
 313         __stringify(__tlb_probe_hazard)                                 \
 314         );                                                              \
 315 } while (0)
 316
 317
 318 #define irq_enable_hazard()                                             \
 319 do {                                                                    \
 320         __asm__ __volatile__(                                           \
 321         __stringify(__irq_enable_hazard)                                \
 322         );                                                              \
 323 } while (0)
 324
 325
 326 #define irq_disable_hazard()                                            \
 327 do {                                                                    \
 328         __asm__ __volatile__(                                           \
 329         __stringify(__irq_disable_hazard)                               \
 330         );                                                              \
 331 } while (0)
 332
 333
 334 #define back_to_back_c0_hazard()                                        \
 335 do {                                                                    \
 336         __asm__ __volatile__(                                           \
 337         __stringify(__back_to_back_c0_hazard)                           \
 338         );                                                              \
 339 } while (0)
 340
 341
 342 #define enable_fpu_hazard()                                             \
 343 do {                                                                    \
 344         __asm__ __volatile__(                                           \
 345         __stringify(__enable_fpu_hazard)                                \
 346         );                                                              \
 347 } while (0)
 348
 349
 350 #define disable_fpu_hazard()                                            \
 351 do {                                                                    \
 352         __asm__ __volatile__(                                           \
 353         __stringify(__disable_fpu_hazard)                               \
 354         );                                                              \
 355 } while (0)
 356
 357 /*
 358  * MIPS R2 instruction hazard barrier.   Needs to be called as a subroutine.
 359  */
 360 extern void mips_ihb(void);
 361
 362 #endif /* __ASSEMBLY__  */
 363
 364 #endif /* _ASM_HAZARDS_H */