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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) 1996 David S. Miller (dm@engr.sgi.com)
   7  * Copyright (C) 1997, 1998, 1999, 2000 Ralf Baechle ralf@gnu.org
   8  * Carsten Langgaard, carstenl@mips.com
   9  * Copyright (C) 2002 MIPS Technologies, Inc.  All rights reserved.
  10  */
  11 #include <linux/init.h>
  12 #include <linux/sched.h>
  13 #include <linux/mm.h>
  14
  15 #include <asm/cpu.h>
  16 #include <asm/bootinfo.h>
  17 #include <asm/mmu_context.h>
  18 #include <asm/pgtable.h>
  19 #include <asm/system.h>
  20
  21 extern void build_tlb_refill_handler(void);
  22
  23 /*
  24  * Make sure all entries differ.  If they're not different
  25  * MIPS32 will take revenge ...
  26  */
  27 #define UNIQUE_ENTRYHI(idx) (CKSEG0 + ((idx) << (PAGE_SHIFT + 1)))
  28
  29 /* Atomicity and interruptability */
  30 #ifdef CONFIG_MIPS_MT_SMTC
  31
  32 #include <asm/smtc.h>
  33 #include <asm/mipsmtregs.h>
  34
  35 #define ENTER_CRITICAL(flags) \
  36         { \
  37         unsigned int mvpflags; \
  38         local_irq_save(flags);\
  39         mvpflags = dvpe()
  40 #define EXIT_CRITICAL(flags) \
  41         evpe(mvpflags); \
  42         local_irq_restore(flags); \
  43         }
  44 #else
  45
  46 #define ENTER_CRITICAL(flags) local_irq_save(flags)
  47 #define EXIT_CRITICAL(flags) local_irq_restore(flags)
  48
  49 #endif /* CONFIG_MIPS_MT_SMTC */
  50
  51 #if defined(CONFIG_CPU_LOONGSON2)
  52 /*
  53  * LOONGSON2 has a 4 entry itlb which is a subset of dtlb,
  54  * unfortrunately, itlb is not totally transparent to software.
  55  */
  56 #define FLUSH_ITLB write_c0_diag(4);
  57
  58 #define FLUSH_ITLB_VM(vma) { if ((vma)->vm_flags & VM_EXEC)  write_c0_diag(4); }
  59
  60 #else
  61
  62 #define FLUSH_ITLB
  63 #define FLUSH_ITLB_VM(vma)
  64
  65 #endif
  66
  67 void local_flush_tlb_all(void)
  68 {
  69         unsigned long flags;
  70         unsigned long old_ctx;
  71         int entry;
  72
  73         ENTER_CRITICAL(flags);
  74         /* Save old context and create impossible VPN2 value */
  75         old_ctx = read_c0_entryhi();
  76         write_c0_entrylo0(0);
  77         write_c0_entrylo1(0);
  78
  79         entry = read_c0_wired();
  80
  81         /* Blast 'em all away. */
  82         while (entry < current_cpu_data.tlbsize) {
  83                 /* Make sure all entries differ. */
  84                 write_c0_entryhi(UNIQUE_ENTRYHI(entry));
  85                 write_c0_index(entry);
  86                 mtc0_tlbw_hazard();
  87                 tlb_write_indexed();
  88                 entry++;
  89         }
  90         tlbw_use_hazard();
  91         write_c0_entryhi(old_ctx);
  92         FLUSH_ITLB;
  93         EXIT_CRITICAL(flags);
  94 }
  95
  96 /* All entries common to a mm share an asid.  To effectively flush
  97    these entries, we just bump the asid. */
  98 void local_flush_tlb_mm(struct mm_struct *mm)
  99 {
 100         int cpu;
 101
 102         preempt_disable();
 103
 104         cpu = smp_processor_id();
 105
 106         if (cpu_context(cpu, mm) != 0) {
 107                 drop_mmu_context(mm, cpu);
 108         }
 109
 110         preempt_enable();
 111 }
 112
 113 void local_flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
 114         unsigned long end)
 115 {
 116         struct mm_struct *mm = vma->vm_mm;
 117         int cpu = smp_processor_id();
 118
 119         if (cpu_context(cpu, mm) != 0) {
 120                 unsigned long size, flags;
 121
 122                 ENTER_CRITICAL(flags);
 123                 size = (end - start + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
 124                 size = (size + 1) >> 1;
 125                 if (size <= current_cpu_data.tlbsize/2) {
 126                         int oldpid = read_c0_entryhi();
 127                         int newpid = cpu_asid(cpu, mm);
 128
 129                         start &= (PAGE_MASK << 1);
 130                         end += ((PAGE_SIZE << 1) - 1);
 131                         end &= (PAGE_MASK << 1);
 132                         while (start < end) {
 133                                 int idx;
 134
 135                                 write_c0_entryhi(start | newpid);
 136                                 start += (PAGE_SIZE << 1);
 137                                 mtc0_tlbw_hazard();
 138                                 tlb_probe();
 139                                 tlb_probe_hazard();
 140                                 idx = read_c0_index();
 141                                 write_c0_entrylo0(0);
 142                                 write_c0_entrylo1(0);
 143                                 if (idx < 0)
 144                                         continue;
 145                                 /* Make sure all entries differ. */
 146                                 write_c0_entryhi(UNIQUE_ENTRYHI(idx));
 147                                 mtc0_tlbw_hazard();
 148                                 tlb_write_indexed();
 149                         }
 150                         tlbw_use_hazard();
 151                         write_c0_entryhi(oldpid);
 152                 } else {
 153                         drop_mmu_context(mm, cpu);
 154                 }
 155                 FLUSH_ITLB;
 156                 EXIT_CRITICAL(flags);
 157         }
 158 }
 159
 160 void local_flush_tlb_kernel_range(unsigned long start, unsigned long end)
 161 {
 162         unsigned long size, flags;
 163
 164         ENTER_CRITICAL(flags);
 165         size = (end - start + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
 166         size = (size + 1) >> 1;
 167         if (size <= current_cpu_data.tlbsize / 2) {
 168                 int pid = read_c0_entryhi();
 169
 170                 start &= (PAGE_MASK << 1);
 171                 end += ((PAGE_SIZE << 1) - 1);
 172                 end &= (PAGE_MASK << 1);
 173
 174                 while (start < end) {
 175                         int idx;
 176
 177                         write_c0_entryhi(start);
 178                         start += (PAGE_SIZE << 1);
 179                         mtc0_tlbw_hazard();
 180                         tlb_probe();
 181                         tlb_probe_hazard();
 182                         idx = read_c0_index();
 183                         write_c0_entrylo0(0);
 184                         write_c0_entrylo1(0);
 185                         if (idx < 0)
 186                                 continue;
 187                         /* Make sure all entries differ. */
 188                         write_c0_entryhi(UNIQUE_ENTRYHI(idx));
 189                         mtc0_tlbw_hazard();
 190                         tlb_write_indexed();
 191                 }
 192                 tlbw_use_hazard();
 193                 write_c0_entryhi(pid);
 194         } else {
 195                 local_flush_tlb_all();
 196         }
 197         FLUSH_ITLB;
 198         EXIT_CRITICAL(flags);
 199 }
 200
 201 void local_flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
 202 {
 203         int cpu = smp_processor_id();
 204
 205         if (cpu_context(cpu, vma->vm_mm) != 0) {
 206                 unsigned long flags;
 207                 int oldpid, newpid, idx;
 208
 209                 newpid = cpu_asid(cpu, vma->vm_mm);
 210                 page &= (PAGE_MASK << 1);
 211                 ENTER_CRITICAL(flags);
 212                 oldpid = read_c0_entryhi();
 213                 write_c0_entryhi(page | newpid);
 214                 mtc0_tlbw_hazard();
 215                 tlb_probe();
 216                 tlb_probe_hazard();
 217                 idx = read_c0_index();
 218                 write_c0_entrylo0(0);
 219                 write_c0_entrylo1(0);
 220                 if (idx < 0)
 221                         goto finish;
 222                 /* Make sure all entries differ. */
 223                 write_c0_entryhi(UNIQUE_ENTRYHI(idx));
 224                 mtc0_tlbw_hazard();
 225                 tlb_write_indexed();
 226                 tlbw_use_hazard();
 227
 228         finish:
 229                 write_c0_entryhi(oldpid);
 230                 FLUSH_ITLB_VM(vma);
 231                 EXIT_CRITICAL(flags);
 232         }
 233 }
 234
 235 /*
 236  * This one is only used for pages with the global bit set so we don't care
 237  * much about the ASID.
 238  */
 239 void local_flush_tlb_one(unsigned long page)
 240 {
 241         unsigned long flags;
 242         int oldpid, idx;
 243
 244         ENTER_CRITICAL(flags);
 245         oldpid = read_c0_entryhi();
 246         page &= (PAGE_MASK << 1);
 247         write_c0_entryhi(page);
 248         mtc0_tlbw_hazard();
 249         tlb_probe();
 250         tlb_probe_hazard();
 251         idx = read_c0_index();
 252         write_c0_entrylo0(0);
 253         write_c0_entrylo1(0);
 254         if (idx >= 0) {
 255                 /* Make sure all entries differ. */
 256                 write_c0_entryhi(UNIQUE_ENTRYHI(idx));
 257                 mtc0_tlbw_hazard();
 258                 tlb_write_indexed();
 259                 tlbw_use_hazard();
 260         }
 261         write_c0_entryhi(oldpid);
 262         FLUSH_ITLB;
 263         EXIT_CRITICAL(flags);
 264 }
 265
 266 /*
 267  * We will need multiple versions of update_mmu_cache(), one that just
 268  * updates the TLB with the new pte(s), and another which also checks
 269  * for the R4k "end of page" hardware bug and does the needy.
 270  */
 271 void __update_tlb(struct vm_area_struct * vma, unsigned long address, pte_t pte)
 272 {
 273         unsigned long flags;
 274         pgd_t *pgdp;
 275         pud_t *pudp;
 276         pmd_t *pmdp;
 277         pte_t *ptep;
 278         int idx, pid;
 279
 280         /*
 281          * Handle debugger faulting in for debugee.
 282          */
 283         if (current->active_mm != vma->vm_mm)
 284                 return;
 285
 286         ENTER_CRITICAL(flags);
 287
 288         pid = read_c0_entryhi() & ASID_MASK;
 289         address &= (PAGE_MASK << 1);
 290         write_c0_entryhi(address | pid);
 291         pgdp = pgd_offset(vma->vm_mm, address);
 292         mtc0_tlbw_hazard();
 293         tlb_probe();
 294         tlb_probe_hazard();
 295         pudp = pud_offset(pgdp, address);
 296         pmdp = pmd_offset(pudp, address);
 297         idx = read_c0_index();
 298         ptep = pte_offset_map(pmdp, address);
 299
 300 #if defined(CONFIG_64BIT_PHYS_ADDR) && defined(CONFIG_CPU_MIPS32)
 301         write_c0_entrylo0(ptep->pte_high);
 302         ptep++;
 303         write_c0_entrylo1(ptep->pte_high);
 304 #else
 305         write_c0_entrylo0(pte_val(*ptep++) >> 6);
 306         write_c0_entrylo1(pte_val(*ptep) >> 6);
 307 #endif
 308         mtc0_tlbw_hazard();
 309         if (idx < 0)
 310                 tlb_write_random();
 311         else
 312                 tlb_write_indexed();
 313         tlbw_use_hazard();
 314         FLUSH_ITLB_VM(vma);
 315         EXIT_CRITICAL(flags);
 316 }
 317
 318 #if 0
 319 static void r4k_update_mmu_cache_hwbug(struct vm_area_struct * vma,
 320                                        unsigned long address, pte_t pte)
 321 {
 322         unsigned long flags;
 323         unsigned int asid;
 324         pgd_t *pgdp;
 325         pmd_t *pmdp;
 326         pte_t *ptep;
 327         int idx;
 328
 329         ENTER_CRITICAL(flags);
 330         address &= (PAGE_MASK << 1);
 331         asid = read_c0_entryhi() & ASID_MASK;
 332         write_c0_entryhi(address | asid);
 333         pgdp = pgd_offset(vma->vm_mm, address);
 334         mtc0_tlbw_hazard();
 335         tlb_probe();
 336         tlb_probe_hazard();
 337         pmdp = pmd_offset(pgdp, address);
 338         idx = read_c0_index();
 339         ptep = pte_offset_map(pmdp, address);
 340         write_c0_entrylo0(pte_val(*ptep++) >> 6);
 341         write_c0_entrylo1(pte_val(*ptep) >> 6);
 342         mtc0_tlbw_hazard();
 343         if (idx < 0)
 344                 tlb_write_random();
 345         else
 346                 tlb_write_indexed();
 347         tlbw_use_hazard();
 348         EXIT_CRITICAL(flags);
 349 }
 350 #endif
 351
 352 void __init add_wired_entry(unsigned long entrylo0, unsigned long entrylo1,
 353         unsigned long entryhi, unsigned long pagemask)
 354 {
 355         unsigned long flags;
 356         unsigned long wired;
 357         unsigned long old_pagemask;
 358         unsigned long old_ctx;
 359
 360         ENTER_CRITICAL(flags);
 361         /* Save old context and create impossible VPN2 value */
 362         old_ctx = read_c0_entryhi();
 363         old_pagemask = read_c0_pagemask();
 364         wired = read_c0_wired();
 365         write_c0_wired(wired + 1);
 366         write_c0_index(wired);
 367         tlbw_use_hazard();      /* What is the hazard here? */
 368         write_c0_pagemask(pagemask);
 369         write_c0_entryhi(entryhi);
 370         write_c0_entrylo0(entrylo0);
 371         write_c0_entrylo1(entrylo1);
 372         mtc0_tlbw_hazard();
 373         tlb_write_indexed();
 374         tlbw_use_hazard();
 375
 376         write_c0_entryhi(old_ctx);
 377         tlbw_use_hazard();      /* What is the hazard here? */
 378         write_c0_pagemask(old_pagemask);
 379         local_flush_tlb_all();
 380         EXIT_CRITICAL(flags);
 381 }
 382
 383 /*
 384  * Used for loading TLB entries before trap_init() has started, when we
 385  * don't actually want to add a wired entry which remains throughout the
 386  * lifetime of the system
 387  */
 388
 389 static int temp_tlb_entry __cpuinitdata;
 390
 391 __init int add_temporary_entry(unsigned long entrylo0, unsigned long entrylo1,
 392                                unsigned long entryhi, unsigned long pagemask)
 393 {
 394         int ret = 0;
 395         unsigned long flags;
 396         unsigned long wired;
 397         unsigned long old_pagemask;
 398         unsigned long old_ctx;
 399
 400         ENTER_CRITICAL(flags);
 401         /* Save old context and create impossible VPN2 value */
 402         old_ctx = read_c0_entryhi();
 403         old_pagemask = read_c0_pagemask();
 404         wired = read_c0_wired();
 405         if (--temp_tlb_entry < wired) {
 406                 printk(KERN_WARNING
 407                        "No TLB space left for add_temporary_entry\n");
 408                 ret = -ENOSPC;
 409                 goto out;
 410         }
 411
 412         write_c0_index(temp_tlb_entry);
 413         write_c0_pagemask(pagemask);
 414         write_c0_entryhi(entryhi);
 415         write_c0_entrylo0(entrylo0);
 416         write_c0_entrylo1(entrylo1);
 417         mtc0_tlbw_hazard();
 418         tlb_write_indexed();
 419         tlbw_use_hazard();
 420
 421         write_c0_entryhi(old_ctx);
 422         write_c0_pagemask(old_pagemask);
 423 out:
 424         EXIT_CRITICAL(flags);
 425         return ret;
 426 }
 427
 428 static void __cpuinit probe_tlb(unsigned long config)
 429 {
 430         struct cpuinfo_mips *c = &current_cpu_data;
 431         unsigned int reg;
 432
 433         /*
 434          * If this isn't a MIPS32 / MIPS64 compliant CPU.  Config 1 register
 435          * is not supported, we assume R4k style.  Cpu probing already figured
 436          * out the number of tlb entries.
 437          */
 438         if ((c->processor_id & 0xff0000) == PRID_COMP_LEGACY)
 439                 return;
 440 #ifdef CONFIG_MIPS_MT_SMTC
 441         /*
 442          * If TLB is shared in SMTC system, total size already
 443          * has been calculated and written into cpu_data tlbsize
 444          */
 445         if((smtc_status & SMTC_TLB_SHARED) == SMTC_TLB_SHARED)
 446                 return;
 447 #endif /* CONFIG_MIPS_MT_SMTC */
 448
 449         reg = read_c0_config1();
 450         if (!((config >> 7) & 3))
 451                 panic("No TLB present");
 452
 453         c->tlbsize = ((reg >> 25) & 0x3f) + 1;
 454 }
 455
 456 static int __cpuinitdata ntlb = 0;
 457 static int __init set_ntlb(char *str)
 458 {
 459         get_option(&str, &ntlb);
 460         return 1;
 461 }
 462
 463 __setup("ntlb=", set_ntlb);
 464
 465 void __cpuinit tlb_init(void)
 466 {
 467         unsigned int config = read_c0_config();
 468
 469         /*
 470          * You should never change this register:
 471          *   - On R4600 1.7 the tlbp never hits for pages smaller than
 472          *     the value in the c0_pagemask register.
 473          *   - The entire mm handling assumes the c0_pagemask register to
 474          *     be set to fixed-size pages.
 475          */
 476         probe_tlb(config);
 477         write_c0_pagemask(PM_DEFAULT_MASK);
 478         write_c0_wired(0);
 479         if (current_cpu_type() == CPU_R10000 ||
 480             current_cpu_type() == CPU_R12000 ||
 481             current_cpu_type() == CPU_R14000)
 482                 write_c0_framemask(0);
 483         temp_tlb_entry = current_cpu_data.tlbsize - 1;
 484
 485         /* From this point on the ARC firmware is dead.  */
 486         local_flush_tlb_all();
 487
 488         /* Did I tell you that ARC SUCKS?  */
 489
 490         if (ntlb) {
 491                 if (ntlb > 1 && ntlb <= current_cpu_data.tlbsize) {
 492                         int wired = current_cpu_data.tlbsize - ntlb;
 493                         write_c0_wired(wired);
 494                         write_c0_index(wired-1);
 495                         printk("Restricting TLB to %d entries\n", ntlb);
 496                 } else
 497                         printk("Ignoring invalid argument ntlb=%d\n", ntlb);
 498         }
 499
 500         build_tlb_refill_handler();
 501 }