arch/mips/mm/tlb-r4k.c

   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 (davem@davemloft.net)
   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/smp.h>
  14 #include <linux/mm.h>
  15 #include <linux/hugetlb.h>
  16
  17 #include <asm/cpu.h>
  18 #include <asm/bootinfo.h>
  19 #include <asm/mmu_context.h>
  20 #include <asm/pgtable.h>
  21 #include <asm/tlbmisc.h>
  22
  23 extern void build_tlb_refill_handler(void);
  24
  25 /*
  26  * Make sure all entries differ.  If they're not different
  27  * MIPS32 will take revenge ...
  28  */
  29 #define UNIQUE_ENTRYHI(idx) (CKSEG0 + ((idx) << (PAGE_SHIFT + 1)))
  30
  31 /* Atomicity and interruptability */
  32 #ifdef CONFIG_MIPS_MT_SMTC
  33
  34 #include <asm/smtc.h>
  35 #include <asm/mipsmtregs.h>
  36
  37 #define ENTER_CRITICAL(flags) \
  38         { \
  39         unsigned int mvpflags; \
  40         local_irq_save(flags);\
  41         mvpflags = dvpe()
  42 #define EXIT_CRITICAL(flags) \
  43         evpe(mvpflags); \
  44         local_irq_restore(flags); \
  45         }
  46 #else
  47
  48 #define ENTER_CRITICAL(flags) local_irq_save(flags)
  49 #define EXIT_CRITICAL(flags) local_irq_restore(flags)
  50
  51 #endif /* CONFIG_MIPS_MT_SMTC */
  52
  53 #if defined(CONFIG_CPU_LOONGSON2)
  54 /*
  55  * LOONGSON2 has a 4 entry itlb which is a subset of dtlb,
  56  * unfortrunately, itlb is not totally transparent to software.
  57  */
  58 #define FLUSH_ITLB write_c0_diag(4);
  59
  60 #define FLUSH_ITLB_VM(vma) { if ((vma)->vm_flags & VM_EXEC)  write_c0_diag(4); }
  61
  62 #else
  63
  64 #define FLUSH_ITLB
  65 #define FLUSH_ITLB_VM(vma)
  66
  67 #endif
  68
  69 void local_flush_tlb_all(void)
  70 {
  71         unsigned long flags;
  72         unsigned long old_ctx;
  73         int entry;
  74
  75         ENTER_CRITICAL(flags);
  76         /* Save old context and create impossible VPN2 value */
  77         old_ctx = read_c0_entryhi();
  78         write_c0_entrylo0(0);
  79         write_c0_entrylo1(0);
  80
  81         entry = read_c0_wired();
  82
  83         /* Blast 'em all away. */
  84         while (entry < current_cpu_data.tlbsize) {
  85                 /* Make sure all entries differ. */
  86                 write_c0_entryhi(UNIQUE_ENTRYHI(entry));
  87                 write_c0_index(entry);
  88                 mtc0_tlbw_hazard();
  89                 tlb_write_indexed();
  90                 entry++;
  91         }
  92         tlbw_use_hazard();
  93         write_c0_entryhi(old_ctx);
  94         FLUSH_ITLB;
  95         EXIT_CRITICAL(flags);
  96 }
  97
  98 /* All entries common to a mm share an asid.  To effectively flush
  99    these entries, we just bump the asid. */
 100 void local_flush_tlb_mm(struct mm_struct *mm)
 101 {
 102         int cpu;
 103
 104         preempt_disable();
 105
 106         cpu = smp_processor_id();
 107
 108         if (cpu_context(cpu, mm) != 0) {
 109                 drop_mmu_context(mm, cpu);
 110         }
 111
 112         preempt_enable();
 113 }
 114
 115 void local_flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
 116         unsigned long end)
 117 {
 118         struct mm_struct *mm = vma->vm_mm;
 119         int cpu = smp_processor_id();
 120
 121         if (cpu_context(cpu, mm) != 0) {
 122                 unsigned long size, flags;
 123
 124                 ENTER_CRITICAL(flags);
 125                 start = round_down(start, PAGE_SIZE << 1);
 126                 end = round_up(end, PAGE_SIZE << 1);
 127                 size = (end - start) >> (PAGE_SHIFT + 1);
 128                 if (size <= current_cpu_data.tlbsize/2) {
 129                         int oldpid = read_c0_entryhi();
 130                         int newpid = cpu_asid(cpu, mm);
 131
 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 #ifdef CONFIG_MIPS_HUGE_TLB_SUPPORT
 299         /* this could be a huge page  */
 300         if (pmd_huge(*pmdp)) {
 301                 unsigned long lo;
 302                 write_c0_pagemask(PM_HUGE_MASK);
 303                 ptep = (pte_t *)pmdp;
 304                 lo = pte_to_entrylo(pte_val(*ptep));
 305                 write_c0_entrylo0(lo);
 306                 write_c0_entrylo1(lo + (HPAGE_SIZE >> 7));
 307
 308                 mtc0_tlbw_hazard();
 309                 if (idx < 0)
 310                         tlb_write_random();
 311                 else
 312                         tlb_write_indexed();
 313                 tlbw_use_hazard();
 314                 write_c0_pagemask(PM_DEFAULT_MASK);
 315         } else
 316 #endif
 317         {
 318                 ptep = pte_offset_map(pmdp, address);
 319
 320 #if defined(CONFIG_64BIT_PHYS_ADDR) && defined(CONFIG_CPU_MIPS32)
 321                 write_c0_entrylo0(ptep->pte_high);
 322                 ptep++;
 323                 write_c0_entrylo1(ptep->pte_high);
 324 #else
 325                 write_c0_entrylo0(pte_to_entrylo(pte_val(*ptep++)));
 326                 write_c0_entrylo1(pte_to_entrylo(pte_val(*ptep)));
 327 #endif
 328                 mtc0_tlbw_hazard();
 329                 if (idx < 0)
 330                         tlb_write_random();
 331                 else
 332                         tlb_write_indexed();
 333         }
 334         tlbw_use_hazard();
 335         FLUSH_ITLB_VM(vma);
 336         EXIT_CRITICAL(flags);
 337 }
 338
 339 void add_wired_entry(unsigned long entrylo0, unsigned long entrylo1,
 340                      unsigned long entryhi, unsigned long pagemask)
 341 {
 342         unsigned long flags;
 343         unsigned long wired;
 344         unsigned long old_pagemask;
 345         unsigned long old_ctx;
 346
 347         ENTER_CRITICAL(flags);
 348         /* Save old context and create impossible VPN2 value */
 349         old_ctx = read_c0_entryhi();
 350         old_pagemask = read_c0_pagemask();
 351         wired = read_c0_wired();
 352         write_c0_wired(wired + 1);
 353         write_c0_index(wired);
 354         tlbw_use_hazard();      /* What is the hazard here? */
 355         write_c0_pagemask(pagemask);
 356         write_c0_entryhi(entryhi);
 357         write_c0_entrylo0(entrylo0);
 358         write_c0_entrylo1(entrylo1);
 359         mtc0_tlbw_hazard();
 360         tlb_write_indexed();
 361         tlbw_use_hazard();
 362
 363         write_c0_entryhi(old_ctx);
 364         tlbw_use_hazard();      /* What is the hazard here? */
 365         write_c0_pagemask(old_pagemask);
 366         local_flush_tlb_all();
 367         EXIT_CRITICAL(flags);
 368 }
 369
 370 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 371
 372 int __init has_transparent_hugepage(void)
 373 {
 374         unsigned int mask;
 375         unsigned long flags;
 376
 377         ENTER_CRITICAL(flags);
 378         write_c0_pagemask(PM_HUGE_MASK);
 379         back_to_back_c0_hazard();
 380         mask = read_c0_pagemask();
 381         write_c0_pagemask(PM_DEFAULT_MASK);
 382
 383         EXIT_CRITICAL(flags);
 384
 385         return mask == PM_HUGE_MASK;
 386 }
 387
 388 #endif /* CONFIG_TRANSPARENT_HUGEPAGE  */
 389
 390 static int __cpuinitdata ntlb;
 391 static int __init set_ntlb(char *str)
 392 {
 393         get_option(&str, &ntlb);
 394         return 1;
 395 }
 396
 397 __setup("ntlb=", set_ntlb);
 398
 399 void __cpuinit tlb_init(void)
 400 {
 401         /*
 402          * You should never change this register:
 403          *   - On R4600 1.7 the tlbp never hits for pages smaller than
 404          *     the value in the c0_pagemask register.
 405          *   - The entire mm handling assumes the c0_pagemask register to
 406          *     be set to fixed-size pages.
 407          */
 408         write_c0_pagemask(PM_DEFAULT_MASK);
 409         write_c0_wired(0);
 410         if (current_cpu_type() == CPU_R10000 ||
 411             current_cpu_type() == CPU_R12000 ||
 412             current_cpu_type() == CPU_R14000)
 413                 write_c0_framemask(0);
 414
 415         if (cpu_has_rixi) {
 416                 /*
 417                  * Enable the no read, no exec bits, and enable large virtual
 418                  * address.
 419                  */
 420                 u32 pg = PG_RIE | PG_XIE;
 421 #ifdef CONFIG_64BIT
 422                 pg |= PG_ELPA;
 423 #endif
 424                 write_c0_pagegrain(pg);
 425         }
 426
 427         /* From this point on the ARC firmware is dead.  */
 428         local_flush_tlb_all();
 429
 430         /* Did I tell you that ARC SUCKS?  */
 431
 432         if (ntlb) {
 433                 if (ntlb > 1 && ntlb <= current_cpu_data.tlbsize) {
 434                         int wired = current_cpu_data.tlbsize - ntlb;
 435                         write_c0_wired(wired);
 436                         write_c0_index(wired-1);
 437                         printk("Restricting TLB to %d entries\n", ntlb);
 438                 } else
 439                         printk("Ignoring invalid argument ntlb=%d\n", ntlb);
 440         }
 441
 442         build_tlb_refill_handler();
 443 }