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 (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 void local_flush_tlb_all(void)
  52 {
  53         unsigned long flags;
  54         unsigned long old_ctx;
  55         int entry;
  56
  57         ENTER_CRITICAL(flags);
  58         /* Save old context and create impossible VPN2 value */
  59         old_ctx = read_c0_entryhi();
  60         write_c0_entrylo0(0);
  61         write_c0_entrylo1(0);
  62
  63         entry = read_c0_wired();
  64
  65         /* Blast 'em all away. */
  66         while (entry < current_cpu_data.tlbsize) {
  67                 /* Make sure all entries differ. */
  68                 write_c0_entryhi(UNIQUE_ENTRYHI(entry));
  69                 write_c0_index(entry);
  70                 mtc0_tlbw_hazard();
  71                 tlb_write_indexed();
  72                 entry++;
  73         }
  74         tlbw_use_hazard();
  75         write_c0_entryhi(old_ctx);
  76         EXIT_CRITICAL(flags);
  77 }
  78
  79 /* All entries common to a mm share an asid.  To effectively flush
  80    these entries, we just bump the asid. */
  81 void local_flush_tlb_mm(struct mm_struct *mm)
  82 {
  83         int cpu;
  84
  85         preempt_disable();
  86
  87         cpu = smp_processor_id();
  88
  89         if (cpu_context(cpu, mm) != 0) {
  90                 drop_mmu_context(mm, cpu);
  91         }
  92
  93         preempt_enable();
  94 }
  95
  96 void local_flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
  97         unsigned long end)
  98 {
  99         struct mm_struct *mm = vma->vm_mm;
 100         int cpu = smp_processor_id();
 101
 102         if (cpu_context(cpu, mm) != 0) {
 103                 unsigned long flags;
 104                 int size;
 105
 106                 ENTER_CRITICAL(flags);
 107                 size = (end - start + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
 108                 size = (size + 1) >> 1;
 109                 if (size <= current_cpu_data.tlbsize/2) {
 110                         int oldpid = read_c0_entryhi();
 111                         int newpid = cpu_asid(cpu, mm);
 112
 113                         start &= (PAGE_MASK << 1);
 114                         end += ((PAGE_SIZE << 1) - 1);
 115                         end &= (PAGE_MASK << 1);
 116                         while (start < end) {
 117                                 int idx;
 118
 119                                 write_c0_entryhi(start | newpid);
 120                                 start += (PAGE_SIZE << 1);
 121                                 mtc0_tlbw_hazard();
 122                                 tlb_probe();
 123                                 tlb_probe_hazard();
 124                                 idx = read_c0_index();
 125                                 write_c0_entrylo0(0);
 126                                 write_c0_entrylo1(0);
 127                                 if (idx < 0)
 128                                         continue;
 129                                 /* Make sure all entries differ. */
 130                                 write_c0_entryhi(UNIQUE_ENTRYHI(idx));
 131                                 mtc0_tlbw_hazard();
 132                                 tlb_write_indexed();
 133                         }
 134                         tlbw_use_hazard();
 135                         write_c0_entryhi(oldpid);
 136                 } else {
 137                         drop_mmu_context(mm, cpu);
 138                 }
 139                 EXIT_CRITICAL(flags);
 140         }
 141 }
 142
 143 void local_flush_tlb_kernel_range(unsigned long start, unsigned long end)
 144 {
 145         unsigned long flags;
 146         int size;
 147
 148         ENTER_CRITICAL(flags);
 149         size = (end - start + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
 150         size = (size + 1) >> 1;
 151         if (size <= current_cpu_data.tlbsize / 2) {
 152                 int pid = read_c0_entryhi();
 153
 154                 start &= (PAGE_MASK << 1);
 155                 end += ((PAGE_SIZE << 1) - 1);
 156                 end &= (PAGE_MASK << 1);
 157
 158                 while (start < end) {
 159                         int idx;
 160
 161                         write_c0_entryhi(start);
 162                         start += (PAGE_SIZE << 1);
 163                         mtc0_tlbw_hazard();
 164                         tlb_probe();
 165                         tlb_probe_hazard();
 166                         idx = read_c0_index();
 167                         write_c0_entrylo0(0);
 168                         write_c0_entrylo1(0);
 169                         if (idx < 0)
 170                                 continue;
 171                         /* Make sure all entries differ. */
 172                         write_c0_entryhi(UNIQUE_ENTRYHI(idx));
 173                         mtc0_tlbw_hazard();
 174                         tlb_write_indexed();
 175                 }
 176                 tlbw_use_hazard();
 177                 write_c0_entryhi(pid);
 178         } else {
 179                 local_flush_tlb_all();
 180         }
 181         EXIT_CRITICAL(flags);
 182 }
 183
 184 void local_flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
 185 {
 186         int cpu = smp_processor_id();
 187
 188         if (cpu_context(cpu, vma->vm_mm) != 0) {
 189                 unsigned long flags;
 190                 int oldpid, newpid, idx;
 191
 192                 newpid = cpu_asid(cpu, vma->vm_mm);
 193                 page &= (PAGE_MASK << 1);
 194                 ENTER_CRITICAL(flags);
 195                 oldpid = read_c0_entryhi();
 196                 write_c0_entryhi(page | newpid);
 197                 mtc0_tlbw_hazard();
 198                 tlb_probe();
 199                 tlb_probe_hazard();
 200                 idx = read_c0_index();
 201                 write_c0_entrylo0(0);
 202                 write_c0_entrylo1(0);
 203                 if (idx < 0)
 204                         goto finish;
 205                 /* Make sure all entries differ. */
 206                 write_c0_entryhi(UNIQUE_ENTRYHI(idx));
 207                 mtc0_tlbw_hazard();
 208                 tlb_write_indexed();
 209                 tlbw_use_hazard();
 210
 211         finish:
 212                 write_c0_entryhi(oldpid);
 213                 EXIT_CRITICAL(flags);
 214         }
 215 }
 216
 217 /*
 218  * This one is only used for pages with the global bit set so we don't care
 219  * much about the ASID.
 220  */
 221 void local_flush_tlb_one(unsigned long page)
 222 {
 223         unsigned long flags;
 224         int oldpid, idx;
 225
 226         ENTER_CRITICAL(flags);
 227         oldpid = read_c0_entryhi();
 228         page &= (PAGE_MASK << 1);
 229         write_c0_entryhi(page);
 230         mtc0_tlbw_hazard();
 231         tlb_probe();
 232         tlb_probe_hazard();
 233         idx = read_c0_index();
 234         write_c0_entrylo0(0);
 235         write_c0_entrylo1(0);
 236         if (idx >= 0) {
 237                 /* Make sure all entries differ. */
 238                 write_c0_entryhi(UNIQUE_ENTRYHI(idx));
 239                 mtc0_tlbw_hazard();
 240                 tlb_write_indexed();
 241                 tlbw_use_hazard();
 242         }
 243         write_c0_entryhi(oldpid);
 244
 245         EXIT_CRITICAL(flags);
 246 }
 247
 248 /*
 249  * We will need multiple versions of update_mmu_cache(), one that just
 250  * updates the TLB with the new pte(s), and another which also checks
 251  * for the R4k "end of page" hardware bug and does the needy.
 252  */
 253 void __update_tlb(struct vm_area_struct * vma, unsigned long address, pte_t pte)
 254 {
 255         unsigned long flags;
 256         pgd_t *pgdp;
 257         pud_t *pudp;
 258         pmd_t *pmdp;
 259         pte_t *ptep;
 260         int idx, pid;
 261
 262         /*
 263          * Handle debugger faulting in for debugee.
 264          */
 265         if (current->active_mm != vma->vm_mm)
 266                 return;
 267
 268         ENTER_CRITICAL(flags);
 269
 270         pid = read_c0_entryhi() & ASID_MASK;
 271         address &= (PAGE_MASK << 1);
 272         write_c0_entryhi(address | pid);
 273         pgdp = pgd_offset(vma->vm_mm, address);
 274         mtc0_tlbw_hazard();
 275         tlb_probe();
 276         tlb_probe_hazard();
 277         pudp = pud_offset(pgdp, address);
 278         pmdp = pmd_offset(pudp, address);
 279         idx = read_c0_index();
 280         ptep = pte_offset_map(pmdp, address);
 281
 282 #if defined(CONFIG_64BIT_PHYS_ADDR) && defined(CONFIG_CPU_MIPS32_R1)
 283         write_c0_entrylo0(ptep->pte_high);
 284         ptep++;
 285         write_c0_entrylo1(ptep->pte_high);
 286 #else
 287         write_c0_entrylo0(pte_val(*ptep++) >> 6);
 288         write_c0_entrylo1(pte_val(*ptep) >> 6);
 289 #endif
 290         mtc0_tlbw_hazard();
 291         if (idx < 0)
 292                 tlb_write_random();
 293         else
 294                 tlb_write_indexed();
 295         tlbw_use_hazard();
 296         EXIT_CRITICAL(flags);
 297 }
 298
 299 #if 0
 300 static void r4k_update_mmu_cache_hwbug(struct vm_area_struct * vma,
 301                                        unsigned long address, pte_t pte)
 302 {
 303         unsigned long flags;
 304         unsigned int asid;
 305         pgd_t *pgdp;
 306         pmd_t *pmdp;
 307         pte_t *ptep;
 308         int idx;
 309
 310         ENTER_CRITICAL(flags);
 311         address &= (PAGE_MASK << 1);
 312         asid = read_c0_entryhi() & ASID_MASK;
 313         write_c0_entryhi(address | asid);
 314         pgdp = pgd_offset(vma->vm_mm, address);
 315         mtc0_tlbw_hazard();
 316         tlb_probe();
 317         tlb_probe_hazard();
 318         pmdp = pmd_offset(pgdp, address);
 319         idx = read_c0_index();
 320         ptep = pte_offset_map(pmdp, address);
 321         write_c0_entrylo0(pte_val(*ptep++) >> 6);
 322         write_c0_entrylo1(pte_val(*ptep) >> 6);
 323         mtc0_tlbw_hazard();
 324         if (idx < 0)
 325                 tlb_write_random();
 326         else
 327                 tlb_write_indexed();
 328         tlbw_use_hazard();
 329         EXIT_CRITICAL(flags);
 330 }
 331 #endif
 332
 333 void __init add_wired_entry(unsigned long entrylo0, unsigned long entrylo1,
 334         unsigned long entryhi, unsigned long pagemask)
 335 {
 336         unsigned long flags;
 337         unsigned long wired;
 338         unsigned long old_pagemask;
 339         unsigned long old_ctx;
 340
 341         ENTER_CRITICAL(flags);
 342         /* Save old context and create impossible VPN2 value */
 343         old_ctx = read_c0_entryhi();
 344         old_pagemask = read_c0_pagemask();
 345         wired = read_c0_wired();
 346         write_c0_wired(wired + 1);
 347         write_c0_index(wired);
 348         tlbw_use_hazard();      /* What is the hazard here? */
 349         write_c0_pagemask(pagemask);
 350         write_c0_entryhi(entryhi);
 351         write_c0_entrylo0(entrylo0);
 352         write_c0_entrylo1(entrylo1);
 353         mtc0_tlbw_hazard();
 354         tlb_write_indexed();
 355         tlbw_use_hazard();
 356
 357         write_c0_entryhi(old_ctx);
 358         tlbw_use_hazard();      /* What is the hazard here? */
 359         write_c0_pagemask(old_pagemask);
 360         local_flush_tlb_all();
 361         EXIT_CRITICAL(flags);
 362 }
 363
 364 /*
 365  * Used for loading TLB entries before trap_init() has started, when we
 366  * don't actually want to add a wired entry which remains throughout the
 367  * lifetime of the system
 368  */
 369
 370 static int temp_tlb_entry __initdata;
 371
 372 __init int add_temporary_entry(unsigned long entrylo0, unsigned long entrylo1,
 373                                unsigned long entryhi, unsigned long pagemask)
 374 {
 375         int ret = 0;
 376         unsigned long flags;
 377         unsigned long wired;
 378         unsigned long old_pagemask;
 379         unsigned long old_ctx;
 380
 381         ENTER_CRITICAL(flags);
 382         /* Save old context and create impossible VPN2 value */
 383         old_ctx = read_c0_entryhi();
 384         old_pagemask = read_c0_pagemask();
 385         wired = read_c0_wired();
 386         if (--temp_tlb_entry < wired) {
 387                 printk(KERN_WARNING
 388                        "No TLB space left for add_temporary_entry\n");
 389                 ret = -ENOSPC;
 390                 goto out;
 391         }
 392
 393         write_c0_index(temp_tlb_entry);
 394         write_c0_pagemask(pagemask);
 395         write_c0_entryhi(entryhi);
 396         write_c0_entrylo0(entrylo0);
 397         write_c0_entrylo1(entrylo1);
 398         mtc0_tlbw_hazard();
 399         tlb_write_indexed();
 400         tlbw_use_hazard();
 401
 402         write_c0_entryhi(old_ctx);
 403         write_c0_pagemask(old_pagemask);
 404 out:
 405         EXIT_CRITICAL(flags);
 406         return ret;
 407 }
 408
 409 static void __init probe_tlb(unsigned long config)
 410 {
 411         struct cpuinfo_mips *c = &current_cpu_data;
 412         unsigned int reg;
 413
 414         /*
 415          * If this isn't a MIPS32 / MIPS64 compliant CPU.  Config 1 register
 416          * is not supported, we assume R4k style.  Cpu probing already figured
 417          * out the number of tlb entries.
 418          */
 419         if ((c->processor_id & 0xff0000) == PRID_COMP_LEGACY)
 420                 return;
 421 #ifdef CONFIG_MIPS_MT_SMTC
 422         /*
 423          * If TLB is shared in SMTC system, total size already
 424          * has been calculated and written into cpu_data tlbsize
 425          */
 426         if((smtc_status & SMTC_TLB_SHARED) == SMTC_TLB_SHARED)
 427                 return;
 428 #endif /* CONFIG_MIPS_MT_SMTC */
 429
 430         reg = read_c0_config1();
 431         if (!((config >> 7) & 3))
 432                 panic("No TLB present");
 433
 434         c->tlbsize = ((reg >> 25) & 0x3f) + 1;
 435 }
 436
 437 static int __initdata ntlb = 0;
 438 static int __init set_ntlb(char *str)
 439 {
 440         get_option(&str, &ntlb);
 441         return 1;
 442 }
 443
 444 __setup("ntlb=", set_ntlb);
 445
 446 void __init tlb_init(void)
 447 {
 448         unsigned int config = read_c0_config();
 449
 450         /*
 451          * You should never change this register:
 452          *   - On R4600 1.7 the tlbp never hits for pages smaller than
 453          *     the value in the c0_pagemask register.
 454          *   - The entire mm handling assumes the c0_pagemask register to
 455          *     be set for 4kb pages.
 456          */
 457         probe_tlb(config);
 458         write_c0_pagemask(PM_DEFAULT_MASK);
 459         write_c0_wired(0);
 460         write_c0_framemask(0);
 461         temp_tlb_entry = current_cpu_data.tlbsize - 1;
 462
 463         /* From this point on the ARC firmware is dead.  */
 464         local_flush_tlb_all();
 465
 466         /* Did I tell you that ARC SUCKS?  */
 467
 468         if (ntlb) {
 469                 if (ntlb > 1 && ntlb <= current_cpu_data.tlbsize) {
 470                         int wired = current_cpu_data.tlbsize - ntlb;
 471                         write_c0_wired(wired);
 472                         write_c0_index(wired-1);
 473                         printk ("Restricting TLB to %d entries\n", ntlb);
 474                 } else
 475                         printk("Ignoring invalid argument ntlb=%d\n", ntlb);
 476         }
 477
 478         build_tlb_refill_handler();
 479 }