linux/arch/mips/mm/pg-r4k.c
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   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, 05 Ralf Baechle (ralf@linux-mips.org)
   7 * Copyright (C) 2007  Maciej W. Rozycki
   8 */
   9#include <linux/init.h>
  10#include <linux/kernel.h>
  11#include <linux/sched.h>
  12#include <linux/mm.h>
  13#include <linux/module.h>
  14#include <linux/proc_fs.h>
  15
  16#include <asm/bugs.h>
  17#include <asm/cacheops.h>
  18#include <asm/inst.h>
  19#include <asm/io.h>
  20#include <asm/page.h>
  21#include <asm/pgtable.h>
  22#include <asm/prefetch.h>
  23#include <asm/system.h>
  24#include <asm/bootinfo.h>
  25#include <asm/mipsregs.h>
  26#include <asm/mmu_context.h>
  27#include <asm/cpu.h>
  28#include <asm/war.h>
  29
  30#define half_scache_line_size() (cpu_scache_line_size() >> 1)
  31#define cpu_is_r4600_v1_x()     ((read_c0_prid() & 0xfffffff0) == 0x00002010)
  32#define cpu_is_r4600_v2_x()     ((read_c0_prid() & 0xfffffff0) == 0x00002020)
  33
  34
  35/*
  36 * Maximum sizes:
  37 *
  38 * R4000 128 bytes S-cache:             0x58 bytes
  39 * R4600 v1.7:                          0x5c bytes
  40 * R4600 v2.0:                          0x60 bytes
  41 * With prefetching, 16 byte strides    0xa0 bytes
  42 */
  43
  44static unsigned int clear_page_array[0x130 / 4];
  45
  46void clear_page(void * page) __attribute__((alias("clear_page_array")));
  47
  48EXPORT_SYMBOL(clear_page);
  49
  50/*
  51 * Maximum sizes:
  52 *
  53 * R4000 128 bytes S-cache:             0x11c bytes
  54 * R4600 v1.7:                          0x080 bytes
  55 * R4600 v2.0:                          0x07c bytes
  56 * With prefetching, 16 byte strides    0x0b8 bytes
  57 */
  58static unsigned int copy_page_array[0x148 / 4];
  59
  60void copy_page(void *to, void *from) __attribute__((alias("copy_page_array")));
  61
  62EXPORT_SYMBOL(copy_page);
  63
  64/*
  65 * This is suboptimal for 32-bit kernels; we assume that R10000 is only used
  66 * with 64-bit kernels.  The prefetch offsets have been experimentally tuned
  67 * an Origin 200.
  68 */
  69static int pref_offset_clear __cpuinitdata = 512;
  70static int pref_offset_copy  __cpuinitdata = 256;
  71
  72static unsigned int pref_src_mode __cpuinitdata;
  73static unsigned int pref_dst_mode __cpuinitdata;
  74
  75static int load_offset __cpuinitdata;
  76static int store_offset __cpuinitdata;
  77
  78static unsigned int __cpuinitdata *dest, *epc;
  79
  80static unsigned int instruction_pending;
  81static union mips_instruction delayed_mi;
  82
  83static void __cpuinit emit_instruction(union mips_instruction mi)
  84{
  85        if (instruction_pending)
  86                *epc++ = delayed_mi.word;
  87
  88        instruction_pending = 1;
  89        delayed_mi = mi;
  90}
  91
  92static inline void flush_delay_slot_or_nop(void)
  93{
  94        if (instruction_pending) {
  95                *epc++ = delayed_mi.word;
  96                instruction_pending = 0;
  97                return;
  98        }
  99
 100        *epc++ = 0;
 101}
 102
 103static inline unsigned int *label(void)
 104{
 105        if (instruction_pending) {
 106                *epc++ = delayed_mi.word;
 107                instruction_pending = 0;
 108        }
 109
 110        return epc;
 111}
 112
 113static inline void build_insn_word(unsigned int word)
 114{
 115        union mips_instruction mi;
 116
 117        mi.word          = word;
 118
 119        emit_instruction(mi);
 120}
 121
 122static inline void build_nop(void)
 123{
 124        build_insn_word(0);                     /* nop */
 125}
 126
 127static inline void build_src_pref(int advance)
 128{
 129        if (!(load_offset & (cpu_dcache_line_size() - 1)) && advance) {
 130                union mips_instruction mi;
 131
 132                mi.i_format.opcode     = pref_op;
 133                mi.i_format.rs         = 5;             /* $a1 */
 134                mi.i_format.rt         = pref_src_mode;
 135                mi.i_format.simmediate = load_offset + advance;
 136
 137                emit_instruction(mi);
 138        }
 139}
 140
 141static inline void __build_load_reg(int reg)
 142{
 143        union mips_instruction mi;
 144        unsigned int width;
 145
 146        if (cpu_has_64bit_gp_regs) {
 147                mi.i_format.opcode     = ld_op;
 148                width = 8;
 149        } else {
 150                mi.i_format.opcode     = lw_op;
 151                width = 4;
 152        }
 153        mi.i_format.rs         = 5;             /* $a1 */
 154        mi.i_format.rt         = reg;           /* $reg */
 155        mi.i_format.simmediate = load_offset;
 156
 157        load_offset += width;
 158        emit_instruction(mi);
 159}
 160
 161static inline void build_load_reg(int reg)
 162{
 163        if (cpu_has_prefetch)
 164                build_src_pref(pref_offset_copy);
 165
 166        __build_load_reg(reg);
 167}
 168
 169static inline void build_dst_pref(int advance)
 170{
 171        if (!(store_offset & (cpu_dcache_line_size() - 1)) && advance) {
 172                union mips_instruction mi;
 173
 174                mi.i_format.opcode     = pref_op;
 175                mi.i_format.rs         = 4;             /* $a0 */
 176                mi.i_format.rt         = pref_dst_mode;
 177                mi.i_format.simmediate = store_offset + advance;
 178
 179                emit_instruction(mi);
 180        }
 181}
 182
 183static inline void build_cdex_s(void)
 184{
 185        union mips_instruction mi;
 186
 187        if ((store_offset & (cpu_scache_line_size() - 1)))
 188                return;
 189
 190        mi.c_format.opcode     = cache_op;
 191        mi.c_format.rs         = 4;             /* $a0 */
 192        mi.c_format.c_op       = 3;             /* Create Dirty Exclusive */
 193        mi.c_format.cache      = 3;             /* Secondary Data Cache */
 194        mi.c_format.simmediate = store_offset;
 195
 196        emit_instruction(mi);
 197}
 198
 199static inline void build_cdex_p(void)
 200{
 201        union mips_instruction mi;
 202
 203        if (store_offset & (cpu_dcache_line_size() - 1))
 204                return;
 205
 206        if (R4600_V1_HIT_CACHEOP_WAR && cpu_is_r4600_v1_x()) {
 207                build_nop();
 208                build_nop();
 209                build_nop();
 210                build_nop();
 211        }
 212
 213        if (R4600_V2_HIT_CACHEOP_WAR && cpu_is_r4600_v2_x())
 214                build_insn_word(0x8c200000);    /* lw      $zero, ($at) */
 215
 216        mi.c_format.opcode     = cache_op;
 217        mi.c_format.rs         = 4;             /* $a0 */
 218        mi.c_format.c_op       = 3;             /* Create Dirty Exclusive */
 219        mi.c_format.cache      = 1;             /* Data Cache */
 220        mi.c_format.simmediate = store_offset;
 221
 222        emit_instruction(mi);
 223}
 224
 225static void __cpuinit __build_store_reg(int reg)
 226{
 227        union mips_instruction mi;
 228        unsigned int width;
 229
 230        if (cpu_has_64bit_gp_regs ||
 231            (cpu_has_64bit_zero_reg && reg == 0)) {
 232                mi.i_format.opcode     = sd_op;
 233                width = 8;
 234        } else {
 235                mi.i_format.opcode     = sw_op;
 236                width = 4;
 237        }
 238        mi.i_format.rs         = 4;             /* $a0 */
 239        mi.i_format.rt         = reg;           /* $reg */
 240        mi.i_format.simmediate = store_offset;
 241
 242        store_offset += width;
 243        emit_instruction(mi);
 244}
 245
 246static inline void build_store_reg(int reg)
 247{
 248        int pref_off = cpu_has_prefetch ?
 249                (reg ? pref_offset_copy : pref_offset_clear) : 0;
 250        if (pref_off)
 251                build_dst_pref(pref_off);
 252        else if (cpu_has_cache_cdex_s)
 253                build_cdex_s();
 254        else if (cpu_has_cache_cdex_p)
 255                build_cdex_p();
 256
 257        __build_store_reg(reg);
 258}
 259
 260static inline void build_addiu_rt_rs(unsigned int rt, unsigned int rs,
 261                                     unsigned long offset)
 262{
 263        union mips_instruction mi;
 264
 265        BUG_ON(offset > 0x7fff);
 266
 267        if (cpu_has_64bit_gp_regs && DADDI_WAR && r4k_daddiu_bug()) {
 268                mi.i_format.opcode     = addiu_op;
 269                mi.i_format.rs         = 0;     /* $zero */
 270                mi.i_format.rt         = 25;    /* $t9 */
 271                mi.i_format.simmediate = offset;
 272                emit_instruction(mi);
 273
 274                mi.r_format.opcode     = spec_op;
 275                mi.r_format.rs         = rs;
 276                mi.r_format.rt         = 25;    /* $t9 */
 277                mi.r_format.rd         = rt;
 278                mi.r_format.re         = 0;
 279                mi.r_format.func       = daddu_op;
 280        } else {
 281                mi.i_format.opcode     = cpu_has_64bit_gp_regs ?
 282                                         daddiu_op : addiu_op;
 283                mi.i_format.rs         = rs;
 284                mi.i_format.rt         = rt;
 285                mi.i_format.simmediate = offset;
 286        }
 287        emit_instruction(mi);
 288}
 289
 290static inline void build_addiu_a2_a0(unsigned long offset)
 291{
 292        build_addiu_rt_rs(6, 4, offset);        /* $a2, $a0, offset */
 293}
 294
 295static inline void build_addiu_a2(unsigned long offset)
 296{
 297        build_addiu_rt_rs(6, 6, offset);        /* $a2, $a2, offset */
 298}
 299
 300static inline void build_addiu_a1(unsigned long offset)
 301{
 302        build_addiu_rt_rs(5, 5, offset);        /* $a1, $a1, offset */
 303
 304        load_offset -= offset;
 305}
 306
 307static inline void build_addiu_a0(unsigned long offset)
 308{
 309        build_addiu_rt_rs(4, 4, offset);        /* $a0, $a0, offset */
 310
 311        store_offset -= offset;
 312}
 313
 314static inline void build_bne(unsigned int *dest)
 315{
 316        union mips_instruction mi;
 317
 318        mi.i_format.opcode = bne_op;
 319        mi.i_format.rs     = 6;                 /* $a2 */
 320        mi.i_format.rt     = 4;                 /* $a0 */
 321        mi.i_format.simmediate = dest - epc - 1;
 322
 323        *epc++ = mi.word;
 324        flush_delay_slot_or_nop();
 325}
 326
 327static inline void build_jr_ra(void)
 328{
 329        union mips_instruction mi;
 330
 331        mi.r_format.opcode = spec_op;
 332        mi.r_format.rs     = 31;
 333        mi.r_format.rt     = 0;
 334        mi.r_format.rd     = 0;
 335        mi.r_format.re     = 0;
 336        mi.r_format.func   = jr_op;
 337
 338        *epc++ = mi.word;
 339        flush_delay_slot_or_nop();
 340}
 341
 342void __cpuinit build_clear_page(void)
 343{
 344        unsigned int loop_start;
 345        unsigned long off;
 346        int i;
 347
 348        epc = (unsigned int *) &clear_page_array;
 349        instruction_pending = 0;
 350        store_offset = 0;
 351
 352        if (cpu_has_prefetch) {
 353                switch (current_cpu_type()) {
 354                case CPU_TX49XX:
 355                        /* TX49 supports only Pref_Load */
 356                        pref_offset_clear = 0;
 357                        pref_offset_copy = 0;
 358                        break;
 359
 360                case CPU_RM9000:
 361                        /*
 362                         * As a workaround for erratum G105 which make the
 363                         * PrepareForStore hint unusable we fall back to
 364                         * StoreRetained on the RM9000.  Once it is known which
 365                         * versions of the RM9000 we'll be able to condition-
 366                         * alize this.
 367                         */
 368
 369                case CPU_R10000:
 370                case CPU_R12000:
 371                case CPU_R14000:
 372                        pref_src_mode = Pref_LoadStreamed;
 373                        pref_dst_mode = Pref_StoreStreamed;
 374                        break;
 375
 376                default:
 377                        pref_src_mode = Pref_LoadStreamed;
 378                        pref_dst_mode = Pref_PrepareForStore;
 379                        break;
 380                }
 381        }
 382
 383        off = PAGE_SIZE - (cpu_has_prefetch ? pref_offset_clear : 0);
 384        if (off > 0x7fff) {
 385                build_addiu_a2_a0(off >> 1);
 386                build_addiu_a2(off >> 1);
 387        } else
 388                build_addiu_a2_a0(off);
 389
 390        if (R4600_V2_HIT_CACHEOP_WAR && cpu_is_r4600_v2_x())
 391                build_insn_word(0x3c01a000);    /* lui     $at, 0xa000  */
 392
 393dest = label();
 394        do {
 395                build_store_reg(0);
 396                build_store_reg(0);
 397                build_store_reg(0);
 398                build_store_reg(0);
 399        } while (store_offset < half_scache_line_size());
 400        build_addiu_a0(2 * store_offset);
 401        loop_start = store_offset;
 402        do {
 403                build_store_reg(0);
 404                build_store_reg(0);
 405                build_store_reg(0);
 406                build_store_reg(0);
 407        } while ((store_offset - loop_start) < half_scache_line_size());
 408        build_bne(dest);
 409
 410        if (cpu_has_prefetch && pref_offset_clear) {
 411                build_addiu_a2_a0(pref_offset_clear);
 412        dest = label();
 413                loop_start = store_offset;
 414                do {
 415                        __build_store_reg(0);
 416                        __build_store_reg(0);
 417                        __build_store_reg(0);
 418                        __build_store_reg(0);
 419                } while ((store_offset - loop_start) < half_scache_line_size());
 420                build_addiu_a0(2 * store_offset);
 421                loop_start = store_offset;
 422                do {
 423                        __build_store_reg(0);
 424                        __build_store_reg(0);
 425                        __build_store_reg(0);
 426                        __build_store_reg(0);
 427                } while ((store_offset - loop_start) < half_scache_line_size());
 428                build_bne(dest);
 429        }
 430
 431        build_jr_ra();
 432
 433        BUG_ON(epc > clear_page_array + ARRAY_SIZE(clear_page_array));
 434
 435        pr_info("Synthesized clear page handler (%u instructions).\n",
 436                (unsigned int)(epc - clear_page_array));
 437
 438        pr_debug("\t.set push\n");
 439        pr_debug("\t.set noreorder\n");
 440        for (i = 0; i < (epc - clear_page_array); i++)
 441                pr_debug("\t.word 0x%08x\n", clear_page_array[i]);
 442        pr_debug("\t.set pop\n");
 443}
 444
 445void __cpuinit build_copy_page(void)
 446{
 447        unsigned int loop_start;
 448        unsigned long off;
 449        int i;
 450
 451        epc = (unsigned int *) &copy_page_array;
 452        store_offset = load_offset = 0;
 453        instruction_pending = 0;
 454
 455        off = PAGE_SIZE - (cpu_has_prefetch ? pref_offset_copy : 0);
 456        if (off > 0x7fff) {
 457                build_addiu_a2_a0(off >> 1);
 458                build_addiu_a2(off >> 1);
 459        } else
 460                build_addiu_a2_a0(off);
 461
 462        if (R4600_V2_HIT_CACHEOP_WAR && cpu_is_r4600_v2_x())
 463                build_insn_word(0x3c01a000);    /* lui     $at, 0xa000  */
 464
 465dest = label();
 466        loop_start = store_offset;
 467        do {
 468                build_load_reg( 8);
 469                build_load_reg( 9);
 470                build_load_reg(10);
 471                build_load_reg(11);
 472                build_store_reg( 8);
 473                build_store_reg( 9);
 474                build_store_reg(10);
 475                build_store_reg(11);
 476        } while ((store_offset - loop_start) < half_scache_line_size());
 477        build_addiu_a0(2 * store_offset);
 478        build_addiu_a1(2 * load_offset);
 479        loop_start = store_offset;
 480        do {
 481                build_load_reg( 8);
 482                build_load_reg( 9);
 483                build_load_reg(10);
 484                build_load_reg(11);
 485                build_store_reg( 8);
 486                build_store_reg( 9);
 487                build_store_reg(10);
 488                build_store_reg(11);
 489        } while ((store_offset - loop_start) < half_scache_line_size());
 490        build_bne(dest);
 491
 492        if (cpu_has_prefetch && pref_offset_copy) {
 493                build_addiu_a2_a0(pref_offset_copy);
 494        dest = label();
 495                loop_start = store_offset;
 496                do {
 497                        __build_load_reg( 8);
 498                        __build_load_reg( 9);
 499                        __build_load_reg(10);
 500                        __build_load_reg(11);
 501                        __build_store_reg( 8);
 502                        __build_store_reg( 9);
 503                        __build_store_reg(10);
 504                        __build_store_reg(11);
 505                } while ((store_offset - loop_start) < half_scache_line_size());
 506                build_addiu_a0(2 * store_offset);
 507                build_addiu_a1(2 * load_offset);
 508                loop_start = store_offset;
 509                do {
 510                        __build_load_reg( 8);
 511                        __build_load_reg( 9);
 512                        __build_load_reg(10);
 513                        __build_load_reg(11);
 514                        __build_store_reg( 8);
 515                        __build_store_reg( 9);
 516                        __build_store_reg(10);
 517                        __build_store_reg(11);
 518                } while ((store_offset - loop_start) < half_scache_line_size());
 519                build_bne(dest);
 520        }
 521
 522        build_jr_ra();
 523
 524        BUG_ON(epc > copy_page_array + ARRAY_SIZE(copy_page_array));
 525
 526        pr_info("Synthesized copy page handler (%u instructions).\n",
 527                (unsigned int)(epc - copy_page_array));
 528
 529        pr_debug("\t.set push\n");
 530        pr_debug("\t.set noreorder\n");
 531        for (i = 0; i < (epc - copy_page_array); i++)
 532                pr_debug("\t.word 0x%08x\n", copy_page_array[i]);
 533        pr_debug("\t.set pop\n");
 534}
 535
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