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/system.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                 size = (end - start + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
 126                 size = (size + 1) >> 1;
 127                 if (size <= current_cpu_data.tlbsize/2) {
 128                         int oldpid = read_c0_entryhi();
 129                         int newpid = cpu_asid(cpu, mm);
 130
 131                         start &= (PAGE_MASK << 1);
 132                         end += ((PAGE_SIZE << 1) - 1);
 133                         end &= (PAGE_MASK << 1);
 134                         while (start < end) {
 135                                 int idx;
 136
 137                                 write_c0_entryhi(start | newpid);
 138                                 start += (PAGE_SIZE << 1);
 139                                 mtc0_tlbw_hazard();
 140                                 tlb_probe();
 141                                 tlb_probe_hazard();
 142                                 idx = read_c0_index();
 143                                 write_c0_entrylo0(0);
 144                                 write_c0_entrylo1(0);
 145                                 if (idx < 0)
 146                                         continue;
 147                                 /* Make sure all entries differ. */
 148                                 write_c0_entryhi(UNIQUE_ENTRYHI(idx));
 149                                 mtc0_tlbw_hazard();
 150                                 tlb_write_indexed();
 151                         }
 152                         tlbw_use_hazard();
 153                         write_c0_entryhi(oldpid);
 154                 } else {
 155                         drop_mmu_context(mm, cpu);
 156                 }
 157                 FLUSH_ITLB;
 158                 EXIT_CRITICAL(flags);
 159         }
 160 }
 161
 162 void local_flush_tlb_kernel_range(unsigned long start, unsigned long end)
 163 {
 164         unsigned long size, flags;
 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 #ifdef CONFIG_HUGETLB_PAGE
 301         /* this could be a huge page  */
 302         if (pmd_huge(*pmdp)) {
 303                 unsigned long lo;
 304                 write_c0_pagemask(PM_HUGE_MASK);
 305                 ptep = (pte_t *)pmdp;
 306                 lo = pte_to_entrylo(pte_val(*ptep));
 307                 write_c0_entrylo0(lo);
 308                 write_c0_entrylo1(lo + (HPAGE_SIZE >> 7));
 309
 310                 mtc0_tlbw_hazard();
 311                 if (idx < 0)
 312                         tlb_write_random();
 313                 else
 314                         tlb_write_indexed();
 315                 write_c0_pagemask(PM_DEFAULT_MASK);
 316         } else
 317 #endif
 318         {
 319                 ptep = pte_offset_map(pmdp, address);
 320
 321 #if defined(CONFIG_64BIT_PHYS_ADDR) && defined(CONFIG_CPU_MIPS32)
 322                 write_c0_entrylo0(ptep->pte_high);
 323                 ptep++;
 324                 write_c0_entrylo1(ptep->pte_high);
 325 #else
 326                 write_c0_entrylo0(pte_to_entrylo(pte_val(*ptep++)));
 327                 write_c0_entrylo1(pte_to_entrylo(pte_val(*ptep)));
 328 #endif
 329                 mtc0_tlbw_hazard();
 330                 if (idx < 0)
 331                         tlb_write_random();
 332                 else
 333                         tlb_write_indexed();
 334         }
 335         tlbw_use_hazard();
 336         FLUSH_ITLB_VM(vma);
 337         EXIT_CRITICAL(flags);
 338 }
 339
 340 void __init add_wired_entry(unsigned long entrylo0, unsigned long entrylo1,
 341         unsigned long entryhi, unsigned long pagemask)
 342 {
 343         unsigned long flags;
 344         unsigned long wired;
 345         unsigned long old_pagemask;
 346         unsigned long old_ctx;
 347
 348         ENTER_CRITICAL(flags);
 349         /* Save old context and create impossible VPN2 value */
 350         old_ctx = read_c0_entryhi();
 351         old_pagemask = read_c0_pagemask();
 352         wired = read_c0_wired();
 353         write_c0_wired(wired + 1);
 354         write_c0_index(wired);
 355         tlbw_use_hazard();      /* What is the hazard here? */
 356         write_c0_pagemask(pagemask);
 357         write_c0_entryhi(entryhi);
 358         write_c0_entrylo0(entrylo0);
 359         write_c0_entrylo1(entrylo1);
 360         mtc0_tlbw_hazard();
 361         tlb_write_indexed();
 362         tlbw_use_hazard();
 363
 364         write_c0_entryhi(old_ctx);
 365         tlbw_use_hazard();      /* What is the hazard here? */
 366         write_c0_pagemask(old_pagemask);
 367         local_flush_tlb_all();
 368         EXIT_CRITICAL(flags);
 369 }
 370
 371 /*
 372  * Used for loading TLB entries before trap_init() has started, when we
 373  * don't actually want to add a wired entry which remains throughout the
 374  * lifetime of the system
 375  */
 376
 377 static int temp_tlb_entry __cpuinitdata;
 378
 379 __init int add_temporary_entry(unsigned long entrylo0, unsigned long entrylo1,
 380                                unsigned long entryhi, unsigned long pagemask)
 381 {
 382         int ret = 0;
 383         unsigned long flags;
 384         unsigned long wired;
 385         unsigned long old_pagemask;
 386         unsigned long old_ctx;
 387
 388         ENTER_CRITICAL(flags);
 389         /* Save old context and create impossible VPN2 value */
 390         old_ctx = read_c0_entryhi();
 391         old_pagemask = read_c0_pagemask();
 392         wired = read_c0_wired();
 393         if (--temp_tlb_entry < wired) {
 394                 printk(KERN_WARNING
 395                        "No TLB space left for add_temporary_entry\n");
 396                 ret = -ENOSPC;
 397                 goto out;
 398         }
 399
 400         write_c0_index(temp_tlb_entry);
 401         write_c0_pagemask(pagemask);
 402         write_c0_entryhi(entryhi);
 403         write_c0_entrylo0(entrylo0);
 404         write_c0_entrylo1(entrylo1);
 405         mtc0_tlbw_hazard();
 406         tlb_write_indexed();
 407         tlbw_use_hazard();
 408
 409         write_c0_entryhi(old_ctx);
 410         write_c0_pagemask(old_pagemask);
 411 out:
 412         EXIT_CRITICAL(flags);
 413         return ret;
 414 }
 415
 416 static int __cpuinitdata ntlb;
 417 static int __init set_ntlb(char *str)
 418 {
 419         get_option(&str, &ntlb);
 420         return 1;
 421 }
 422
 423 __setup("ntlb=", set_ntlb);
 424
 425 void __cpuinit tlb_init(void)
 426 {
 427         /*
 428          * You should never change this register:
 429          *   - On R4600 1.7 the tlbp never hits for pages smaller than
 430          *     the value in the c0_pagemask register.
 431          *   - The entire mm handling assumes the c0_pagemask register to
 432          *     be set to fixed-size pages.
 433          */
 434         write_c0_pagemask(PM_DEFAULT_MASK);
 435         write_c0_wired(0);
 436         if (current_cpu_type() == CPU_R10000 ||
 437             current_cpu_type() == CPU_R12000 ||
 438             current_cpu_type() == CPU_R14000)
 439                 write_c0_framemask(0);
 440
 441         if (kernel_uses_smartmips_rixi) {
 442                 /*
 443                  * Enable the no read, no exec bits, and enable large virtual
 444                  * address.
 445                  */
 446                 u32 pg = PG_RIE | PG_XIE;
 447 #ifdef CONFIG_64BIT
 448                 pg |= PG_ELPA;
 449 #endif
 450                 write_c0_pagegrain(pg);
 451         }
 452
 453         temp_tlb_entry = current_cpu_data.tlbsize - 1;
 454
 455         /* From this point on the ARC firmware is dead.  */
 456         local_flush_tlb_all();
 457
 458         /* Did I tell you that ARC SUCKS?  */
 459
 460         if (ntlb) {
 461                 if (ntlb > 1 && ntlb <= current_cpu_data.tlbsize) {
 462                         int wired = current_cpu_data.tlbsize - ntlb;
 463                         write_c0_wired(wired);
 464                         write_c0_index(wired-1);
 465                         printk("Restricting TLB to %d entries\n", ntlb);
 466                 } else
 467                         printk("Ignoring invalid argument ntlb=%d\n", ntlb);
 468         }
 469
 470         build_tlb_refill_handler();
 471 }