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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 flags;
 121                 int size;
 122
 123                 ENTER_CRITICAL(flags);
 124                 size = (end - start + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
 125                 size = (size + 1) >> 1;
 126                 if (size <= current_cpu_data.tlbsize/2) {
 127                         int oldpid = read_c0_entryhi();
 128                         int newpid = cpu_asid(cpu, mm);
 129
 130                         start &= (PAGE_MASK << 1);
 131                         end += ((PAGE_SIZE << 1) - 1);
 132                         end &= (PAGE_MASK << 1);
 133                         while (start < end) {
 134                                 int idx;
 135
 136                                 write_c0_entryhi(start | newpid);
 137                                 start += (PAGE_SIZE << 1);
 138                                 mtc0_tlbw_hazard();
 139                                 tlb_probe();
 140                                 tlb_probe_hazard();
 141                                 idx = read_c0_index();
 142                                 write_c0_entrylo0(0);
 143                                 write_c0_entrylo1(0);
 144                                 if (idx < 0)
 145                                         continue;
 146                                 /* Make sure all entries differ. */
 147                                 write_c0_entryhi(UNIQUE_ENTRYHI(idx));
 148                                 mtc0_tlbw_hazard();
 149                                 tlb_write_indexed();
 150                         }
 151                         tlbw_use_hazard();
 152                         write_c0_entryhi(oldpid);
 153                 } else {
 154                         drop_mmu_context(mm, cpu);
 155                 }
 156                 FLUSH_ITLB;
 157                 EXIT_CRITICAL(flags);
 158         }
 159 }
 160
 161 void local_flush_tlb_kernel_range(unsigned long start, unsigned long end)
 162 {
 163         unsigned long flags;
 164         int size;
 165
 166         ENTER_CRITICAL(flags);
 167         size = (end - start + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
 168         size = (size + 1) >> 1;
 169         if (size <= current_cpu_data.tlbsize / 2) {
 170                 int pid = read_c0_entryhi();
 171
 172                 start &= (PAGE_MASK << 1);
 173                 end += ((PAGE_SIZE << 1) - 1);
 174                 end &= (PAGE_MASK << 1);
 175
 176                 while (start < end) {
 177                         int idx;
 178
 179                         write_c0_entryhi(start);
 180                         start += (PAGE_SIZE << 1);
 181                         mtc0_tlbw_hazard();
 182                         tlb_probe();
 183                         tlb_probe_hazard();
 184                         idx = read_c0_index();
 185                         write_c0_entrylo0(0);
 186                         write_c0_entrylo1(0);
 187                         if (idx < 0)
 188                                 continue;
 189                         /* Make sure all entries differ. */
 190                         write_c0_entryhi(UNIQUE_ENTRYHI(idx));
 191                         mtc0_tlbw_hazard();
 192                         tlb_write_indexed();
 193                 }
 194                 tlbw_use_hazard();
 195                 write_c0_entryhi(pid);
 196         } else {
 197                 local_flush_tlb_all();
 198         }
 199         FLUSH_ITLB;
 200         EXIT_CRITICAL(flags);
 201 }
 202
 203 void local_flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
 204 {
 205         int cpu = smp_processor_id();
 206
 207         if (cpu_context(cpu, vma->vm_mm) != 0) {
 208                 unsigned long flags;
 209                 int oldpid, newpid, idx;
 210
 211                 newpid = cpu_asid(cpu, vma->vm_mm);
 212                 page &= (PAGE_MASK << 1);
 213                 ENTER_CRITICAL(flags);
 214                 oldpid = read_c0_entryhi();
 215                 write_c0_entryhi(page | newpid);
 216                 mtc0_tlbw_hazard();
 217                 tlb_probe();
 218                 tlb_probe_hazard();
 219                 idx = read_c0_index();
 220                 write_c0_entrylo0(0);
 221                 write_c0_entrylo1(0);
 222                 if (idx < 0)
 223                         goto finish;
 224                 /* Make sure all entries differ. */
 225                 write_c0_entryhi(UNIQUE_ENTRYHI(idx));
 226                 mtc0_tlbw_hazard();
 227                 tlb_write_indexed();
 228                 tlbw_use_hazard();
 229
 230         finish:
 231                 write_c0_entryhi(oldpid);
 232                 FLUSH_ITLB_VM(vma);
 233                 EXIT_CRITICAL(flags);
 234         }
 235 }
 236
 237 /*
 238  * This one is only used for pages with the global bit set so we don't care
 239  * much about the ASID.
 240  */
 241 void local_flush_tlb_one(unsigned long page)
 242 {
 243         unsigned long flags;
 244         int oldpid, idx;
 245
 246         ENTER_CRITICAL(flags);
 247         oldpid = read_c0_entryhi();
 248         page &= (PAGE_MASK << 1);
 249         write_c0_entryhi(page);
 250         mtc0_tlbw_hazard();
 251         tlb_probe();
 252         tlb_probe_hazard();
 253         idx = read_c0_index();
 254         write_c0_entrylo0(0);
 255         write_c0_entrylo1(0);
 256         if (idx >= 0) {
 257                 /* Make sure all entries differ. */
 258                 write_c0_entryhi(UNIQUE_ENTRYHI(idx));
 259                 mtc0_tlbw_hazard();
 260                 tlb_write_indexed();
 261                 tlbw_use_hazard();
 262         }
 263         write_c0_entryhi(oldpid);
 264         FLUSH_ITLB;
 265         EXIT_CRITICAL(flags);
 266 }
 267
 268 /*
 269  * We will need multiple versions of update_mmu_cache(), one that just
 270  * updates the TLB with the new pte(s), and another which also checks
 271  * for the R4k "end of page" hardware bug and does the needy.
 272  */
 273 void __update_tlb(struct vm_area_struct * vma, unsigned long address, pte_t pte)
 274 {
 275         unsigned long flags;
 276         pgd_t *pgdp;
 277         pud_t *pudp;
 278         pmd_t *pmdp;
 279         pte_t *ptep;
 280         int idx, pid;
 281
 282         /*
 283          * Handle debugger faulting in for debugee.
 284          */
 285         if (current->active_mm != vma->vm_mm)
 286                 return;
 287
 288         ENTER_CRITICAL(flags);
 289
 290         pid = read_c0_entryhi() & ASID_MASK;
 291         address &= (PAGE_MASK << 1);
 292         write_c0_entryhi(address | pid);
 293         pgdp = pgd_offset(vma->vm_mm, address);
 294         mtc0_tlbw_hazard();
 295         tlb_probe();
 296         tlb_probe_hazard();
 297         pudp = pud_offset(pgdp, address);
 298         pmdp = pmd_offset(pudp, address);
 299         idx = read_c0_index();
 300         ptep = pte_offset_map(pmdp, address);
 301
 302 #if defined(CONFIG_64BIT_PHYS_ADDR) && defined(CONFIG_CPU_MIPS32_R1)
 303         write_c0_entrylo0(ptep->pte_high);
 304         ptep++;
 305         write_c0_entrylo1(ptep->pte_high);
 306 #else
 307         write_c0_entrylo0(pte_val(*ptep++) >> 6);
 308         write_c0_entrylo1(pte_val(*ptep) >> 6);
 309 #endif
 310         mtc0_tlbw_hazard();
 311         if (idx < 0)
 312                 tlb_write_random();
 313         else
 314                 tlb_write_indexed();
 315         tlbw_use_hazard();
 316         FLUSH_ITLB_VM(vma);
 317         EXIT_CRITICAL(flags);
 318 }
 319
 320 #if 0
 321 static void r4k_update_mmu_cache_hwbug(struct vm_area_struct * vma,
 322                                        unsigned long address, pte_t pte)
 323 {
 324         unsigned long flags;
 325         unsigned int asid;
 326         pgd_t *pgdp;
 327         pmd_t *pmdp;
 328         pte_t *ptep;
 329         int idx;
 330
 331         ENTER_CRITICAL(flags);
 332         address &= (PAGE_MASK << 1);
 333         asid = read_c0_entryhi() & ASID_MASK;
 334         write_c0_entryhi(address | asid);
 335         pgdp = pgd_offset(vma->vm_mm, address);
 336         mtc0_tlbw_hazard();
 337         tlb_probe();
 338         tlb_probe_hazard();
 339         pmdp = pmd_offset(pgdp, address);
 340         idx = read_c0_index();
 341         ptep = pte_offset_map(pmdp, address);
 342         write_c0_entrylo0(pte_val(*ptep++) >> 6);
 343         write_c0_entrylo1(pte_val(*ptep) >> 6);
 344         mtc0_tlbw_hazard();
 345         if (idx < 0)
 346                 tlb_write_random();
 347         else
 348                 tlb_write_indexed();
 349         tlbw_use_hazard();
 350         EXIT_CRITICAL(flags);
 351 }
 352 #endif
 353
 354 void __init add_wired_entry(unsigned long entrylo0, unsigned long entrylo1,
 355         unsigned long entryhi, unsigned long pagemask)
 356 {
 357         unsigned long flags;
 358         unsigned long wired;
 359         unsigned long old_pagemask;
 360         unsigned long old_ctx;
 361
 362         ENTER_CRITICAL(flags);
 363         /* Save old context and create impossible VPN2 value */
 364         old_ctx = read_c0_entryhi();
 365         old_pagemask = read_c0_pagemask();
 366         wired = read_c0_wired();
 367         write_c0_wired(wired + 1);
 368         write_c0_index(wired);
 369         tlbw_use_hazard();      /* What is the hazard here? */
 370         write_c0_pagemask(pagemask);
 371         write_c0_entryhi(entryhi);
 372         write_c0_entrylo0(entrylo0);
 373         write_c0_entrylo1(entrylo1);
 374         mtc0_tlbw_hazard();
 375         tlb_write_indexed();
 376         tlbw_use_hazard();
 377
 378         write_c0_entryhi(old_ctx);
 379         tlbw_use_hazard();      /* What is the hazard here? */
 380         write_c0_pagemask(old_pagemask);
 381         local_flush_tlb_all();
 382         EXIT_CRITICAL(flags);
 383 }
 384
 385 /*
 386  * Used for loading TLB entries before trap_init() has started, when we
 387  * don't actually want to add a wired entry which remains throughout the
 388  * lifetime of the system
 389  */
 390
 391 static int temp_tlb_entry __initdata;
 392
 393 __init int add_temporary_entry(unsigned long entrylo0, unsigned long entrylo1,
 394                                unsigned long entryhi, unsigned long pagemask)
 395 {
 396         int ret = 0;
 397         unsigned long flags;
 398         unsigned long wired;
 399         unsigned long old_pagemask;
 400         unsigned long old_ctx;
 401
 402         ENTER_CRITICAL(flags);
 403         /* Save old context and create impossible VPN2 value */
 404         old_ctx = read_c0_entryhi();
 405         old_pagemask = read_c0_pagemask();
 406         wired = read_c0_wired();
 407         if (--temp_tlb_entry < wired) {
 408                 printk(KERN_WARNING
 409                        "No TLB space left for add_temporary_entry\n");
 410                 ret = -ENOSPC;
 411                 goto out;
 412         }
 413
 414         write_c0_index(temp_tlb_entry);
 415         write_c0_pagemask(pagemask);
 416         write_c0_entryhi(entryhi);
 417         write_c0_entrylo0(entrylo0);
 418         write_c0_entrylo1(entrylo1);
 419         mtc0_tlbw_hazard();
 420         tlb_write_indexed();
 421         tlbw_use_hazard();
 422
 423         write_c0_entryhi(old_ctx);
 424         write_c0_pagemask(old_pagemask);
 425 out:
 426         EXIT_CRITICAL(flags);
 427         return ret;
 428 }
 429
 430 static void __init probe_tlb(unsigned long config)
 431 {
 432         struct cpuinfo_mips *c = &current_cpu_data;
 433         unsigned int reg;
 434
 435         /*
 436          * If this isn't a MIPS32 / MIPS64 compliant CPU.  Config 1 register
 437          * is not supported, we assume R4k style.  Cpu probing already figured
 438          * out the number of tlb entries.
 439          */
 440         if ((c->processor_id & 0xff0000) == PRID_COMP_LEGACY)
 441                 return;
 442 #ifdef CONFIG_MIPS_MT_SMTC
 443         /*
 444          * If TLB is shared in SMTC system, total size already
 445          * has been calculated and written into cpu_data tlbsize
 446          */
 447         if((smtc_status & SMTC_TLB_SHARED) == SMTC_TLB_SHARED)
 448                 return;
 449 #endif /* CONFIG_MIPS_MT_SMTC */
 450
 451         reg = read_c0_config1();
 452         if (!((config >> 7) & 3))
 453                 panic("No TLB present");
 454
 455         c->tlbsize = ((reg >> 25) & 0x3f) + 1;
 456 }
 457
 458 static int __initdata ntlb = 0;
 459 static int __init set_ntlb(char *str)
 460 {
 461         get_option(&str, &ntlb);
 462         return 1;
 463 }
 464
 465 __setup("ntlb=", set_ntlb);
 466
 467 void __init tlb_init(void)
 468 {
 469         unsigned int config = read_c0_config();
 470
 471         /*
 472          * You should never change this register:
 473          *   - On R4600 1.7 the tlbp never hits for pages smaller than
 474          *     the value in the c0_pagemask register.
 475          *   - The entire mm handling assumes the c0_pagemask register to
 476          *     be set for 4kb pages.
 477          */
 478         probe_tlb(config);
 479         write_c0_pagemask(PM_DEFAULT_MASK);
 480         write_c0_wired(0);
 481         write_c0_framemask(0);
 482         temp_tlb_entry = current_cpu_data.tlbsize - 1;
 483
 484         /* From this point on the ARC firmware is dead.  */
 485         local_flush_tlb_all();
 486
 487         /* Did I tell you that ARC SUCKS?  */
 488
 489         if (ntlb) {
 490                 if (ntlb > 1 && ntlb <= current_cpu_data.tlbsize) {
 491                         int wired = current_cpu_data.tlbsize - ntlb;
 492                         write_c0_wired(wired);
 493                         write_c0_index(wired-1);
 494                         printk("Restricting TLB to %d entries\n", ntlb);
 495                 } else
 496                         printk("Ignoring invalid argument ntlb=%d\n", ntlb);
 497         }
 498
 499         build_tlb_refill_handler();
 500 }