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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/config.h>
  12 #include <linux/init.h>
  13 #include <linux/sched.h>
  14 #include <linux/mm.h>
  15
  16 #include <asm/cpu.h>
  17 #include <asm/bootinfo.h>
  18 #include <asm/mmu_context.h>
  19 #include <asm/pgtable.h>
  20 #include <asm/system.h>
  21
  22 extern void build_tlb_refill_handler(void);
  23
  24 /*
  25  * Make sure all entries differ.  If they're not different
  26  * MIPS32 will take revenge ...
  27  */
  28 #define UNIQUE_ENTRYHI(idx) (CKSEG0 + ((idx) << (PAGE_SHIFT + 1)))
  29
  30 /* CP0 hazard avoidance. */
  31 #define BARRIER __asm__ __volatile__(".set noreorder\n\t" \
  32                                      "nop; nop; nop; nop; nop; nop;\n\t" \
  33                                      ".set reorder\n\t")
  34
  35 /* Atomicity and interruptability */
  36 #ifdef CONFIG_MIPS_MT_SMTC
  37
  38 #include <asm/smtc.h>
  39 #include <asm/mipsmtregs.h>
  40
  41 #define ENTER_CRITICAL(flags) \
  42         { \
  43         unsigned int mvpflags; \
  44         local_irq_save(flags);\
  45         mvpflags = dvpe()
  46 #define EXIT_CRITICAL(flags) \
  47         evpe(mvpflags); \
  48         local_irq_restore(flags); \
  49         }
  50 #else
  51
  52 #define ENTER_CRITICAL(flags) local_irq_save(flags)
  53 #define EXIT_CRITICAL(flags) local_irq_restore(flags)
  54
  55 #endif /* CONFIG_MIPS_MT_SMTC */
  56
  57 void local_flush_tlb_all(void)
  58 {
  59         unsigned long flags;
  60         unsigned long old_ctx;
  61         int entry;
  62
  63         ENTER_CRITICAL(flags);
  64         /* Save old context and create impossible VPN2 value */
  65         old_ctx = read_c0_entryhi();
  66         write_c0_entrylo0(0);
  67         write_c0_entrylo1(0);
  68
  69         entry = read_c0_wired();
  70
  71         /* Blast 'em all away. */
  72         while (entry < current_cpu_data.tlbsize) {
  73                 /* Make sure all entries differ. */
  74                 write_c0_entryhi(UNIQUE_ENTRYHI(entry));
  75                 write_c0_index(entry);
  76                 mtc0_tlbw_hazard();
  77                 tlb_write_indexed();
  78                 entry++;
  79         }
  80         tlbw_use_hazard();
  81         write_c0_entryhi(old_ctx);
  82         EXIT_CRITICAL(flags);
  83 }
  84
  85 /* All entries common to a mm share an asid.  To effectively flush
  86    these entries, we just bump the asid. */
  87 void local_flush_tlb_mm(struct mm_struct *mm)
  88 {
  89         int cpu;
  90
  91         preempt_disable();
  92
  93         cpu = smp_processor_id();
  94
  95         if (cpu_context(cpu, mm) != 0) {
  96                 drop_mmu_context(mm, cpu);
  97         }
  98
  99         preempt_enable();
 100 }
 101
 102 void local_flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
 103         unsigned long end)
 104 {
 105         struct mm_struct *mm = vma->vm_mm;
 106         int cpu = smp_processor_id();
 107
 108         if (cpu_context(cpu, mm) != 0) {
 109                 unsigned long flags;
 110                 int size;
 111
 112                 ENTER_CRITICAL(flags);
 113                 size = (end - start + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
 114                 size = (size + 1) >> 1;
 115                 local_irq_save(flags);
 116                 if (size <= current_cpu_data.tlbsize/2) {
 117                         int oldpid = read_c0_entryhi();
 118                         int newpid = cpu_asid(cpu, mm);
 119
 120                         start &= (PAGE_MASK << 1);
 121                         end += ((PAGE_SIZE << 1) - 1);
 122                         end &= (PAGE_MASK << 1);
 123                         while (start < end) {
 124                                 int idx;
 125
 126                                 write_c0_entryhi(start | newpid);
 127                                 start += (PAGE_SIZE << 1);
 128                                 mtc0_tlbw_hazard();
 129                                 tlb_probe();
 130                                 BARRIER;
 131                                 idx = read_c0_index();
 132                                 write_c0_entrylo0(0);
 133                                 write_c0_entrylo1(0);
 134                                 if (idx < 0)
 135                                         continue;
 136                                 /* Make sure all entries differ. */
 137                                 write_c0_entryhi(UNIQUE_ENTRYHI(idx));
 138                                 mtc0_tlbw_hazard();
 139                                 tlb_write_indexed();
 140                         }
 141                         tlbw_use_hazard();
 142                         write_c0_entryhi(oldpid);
 143                 } else {
 144                         drop_mmu_context(mm, cpu);
 145                 }
 146                 EXIT_CRITICAL(flags);
 147         }
 148 }
 149
 150 void local_flush_tlb_kernel_range(unsigned long start, unsigned long end)
 151 {
 152         unsigned long flags;
 153         int size;
 154
 155         ENTER_CRITICAL(flags);
 156         size = (end - start + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
 157         size = (size + 1) >> 1;
 158         if (size <= current_cpu_data.tlbsize / 2) {
 159                 int pid = read_c0_entryhi();
 160
 161                 start &= (PAGE_MASK << 1);
 162                 end += ((PAGE_SIZE << 1) - 1);
 163                 end &= (PAGE_MASK << 1);
 164
 165                 while (start < end) {
 166                         int idx;
 167
 168                         write_c0_entryhi(start);
 169                         start += (PAGE_SIZE << 1);
 170                         mtc0_tlbw_hazard();
 171                         tlb_probe();
 172                         BARRIER;
 173                         idx = read_c0_index();
 174                         write_c0_entrylo0(0);
 175                         write_c0_entrylo1(0);
 176                         if (idx < 0)
 177                                 continue;
 178                         /* Make sure all entries differ. */
 179                         write_c0_entryhi(UNIQUE_ENTRYHI(idx));
 180                         mtc0_tlbw_hazard();
 181                         tlb_write_indexed();
 182                 }
 183                 tlbw_use_hazard();
 184                 write_c0_entryhi(pid);
 185         } else {
 186                 local_flush_tlb_all();
 187         }
 188         EXIT_CRITICAL(flags);
 189 }
 190
 191 void local_flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
 192 {
 193         int cpu = smp_processor_id();
 194
 195         if (cpu_context(cpu, vma->vm_mm) != 0) {
 196                 unsigned long flags;
 197                 int oldpid, newpid, idx;
 198
 199                 newpid = cpu_asid(cpu, vma->vm_mm);
 200                 page &= (PAGE_MASK << 1);
 201                 ENTER_CRITICAL(flags);
 202                 oldpid = read_c0_entryhi();
 203                 write_c0_entryhi(page | newpid);
 204                 mtc0_tlbw_hazard();
 205                 tlb_probe();
 206                 BARRIER;
 207                 idx = read_c0_index();
 208                 write_c0_entrylo0(0);
 209                 write_c0_entrylo1(0);
 210                 if (idx < 0)
 211                         goto finish;
 212                 /* Make sure all entries differ. */
 213                 write_c0_entryhi(UNIQUE_ENTRYHI(idx));
 214                 mtc0_tlbw_hazard();
 215                 tlb_write_indexed();
 216                 tlbw_use_hazard();
 217
 218         finish:
 219                 write_c0_entryhi(oldpid);
 220                 EXIT_CRITICAL(flags);
 221         }
 222 }
 223
 224 /*
 225  * This one is only used for pages with the global bit set so we don't care
 226  * much about the ASID.
 227  */
 228 void local_flush_tlb_one(unsigned long page)
 229 {
 230         unsigned long flags;
 231         int oldpid, idx;
 232
 233         ENTER_CRITICAL(flags);
 234         oldpid = read_c0_entryhi();
 235         page &= (PAGE_MASK << 1);
 236         write_c0_entryhi(page);
 237         mtc0_tlbw_hazard();
 238         tlb_probe();
 239         BARRIER;
 240         idx = read_c0_index();
 241         write_c0_entrylo0(0);
 242         write_c0_entrylo1(0);
 243         if (idx >= 0) {
 244                 /* Make sure all entries differ. */
 245                 write_c0_entryhi(UNIQUE_ENTRYHI(idx));
 246                 mtc0_tlbw_hazard();
 247                 tlb_write_indexed();
 248                 tlbw_use_hazard();
 249         }
 250         write_c0_entryhi(oldpid);
 251
 252         EXIT_CRITICAL(flags);
 253 }
 254
 255 /*
 256  * We will need multiple versions of update_mmu_cache(), one that just
 257  * updates the TLB with the new pte(s), and another which also checks
 258  * for the R4k "end of page" hardware bug and does the needy.
 259  */
 260 void __update_tlb(struct vm_area_struct * vma, unsigned long address, pte_t pte)
 261 {
 262         unsigned long flags;
 263         pgd_t *pgdp;
 264         pud_t *pudp;
 265         pmd_t *pmdp;
 266         pte_t *ptep;
 267         int idx, pid;
 268
 269         /*
 270          * Handle debugger faulting in for debugee.
 271          */
 272         if (current->active_mm != vma->vm_mm)
 273                 return;
 274
 275         ENTER_CRITICAL(flags);
 276
 277         pid = read_c0_entryhi() & ASID_MASK;
 278         address &= (PAGE_MASK << 1);
 279         write_c0_entryhi(address | pid);
 280         pgdp = pgd_offset(vma->vm_mm, address);
 281         mtc0_tlbw_hazard();
 282         tlb_probe();
 283         BARRIER;
 284         pudp = pud_offset(pgdp, address);
 285         pmdp = pmd_offset(pudp, address);
 286         idx = read_c0_index();
 287         ptep = pte_offset_map(pmdp, address);
 288
 289 #if defined(CONFIG_64BIT_PHYS_ADDR) && defined(CONFIG_CPU_MIPS32_R1)
 290         write_c0_entrylo0(ptep->pte_high);
 291         ptep++;
 292         write_c0_entrylo1(ptep->pte_high);
 293 #else
 294         write_c0_entrylo0(pte_val(*ptep++) >> 6);
 295         write_c0_entrylo1(pte_val(*ptep) >> 6);
 296 #endif
 297         mtc0_tlbw_hazard();
 298         if (idx < 0)
 299                 tlb_write_random();
 300         else
 301                 tlb_write_indexed();
 302         tlbw_use_hazard();
 303         EXIT_CRITICAL(flags);
 304 }
 305
 306 #if 0
 307 static void r4k_update_mmu_cache_hwbug(struct vm_area_struct * vma,
 308                                        unsigned long address, pte_t pte)
 309 {
 310         unsigned long flags;
 311         unsigned int asid;
 312         pgd_t *pgdp;
 313         pmd_t *pmdp;
 314         pte_t *ptep;
 315         int idx;
 316
 317         ENTER_CRITICAL(flags);
 318         address &= (PAGE_MASK << 1);
 319         asid = read_c0_entryhi() & ASID_MASK;
 320         write_c0_entryhi(address | asid);
 321         pgdp = pgd_offset(vma->vm_mm, address);
 322         mtc0_tlbw_hazard();
 323         tlb_probe();
 324         BARRIER;
 325         pmdp = pmd_offset(pgdp, address);
 326         idx = read_c0_index();
 327         ptep = pte_offset_map(pmdp, address);
 328         write_c0_entrylo0(pte_val(*ptep++) >> 6);
 329         write_c0_entrylo1(pte_val(*ptep) >> 6);
 330         mtc0_tlbw_hazard();
 331         if (idx < 0)
 332                 tlb_write_random();
 333         else
 334                 tlb_write_indexed();
 335         tlbw_use_hazard();
 336         EXIT_CRITICAL(flags);
 337 }
 338 #endif
 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         BARRIER;
 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         BARRIER;
 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 __initdata;
 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 extern void __init sanitize_tlb_entries(void);
 417 static void __init probe_tlb(unsigned long config)
 418 {
 419         struct cpuinfo_mips *c = &current_cpu_data;
 420         unsigned int reg;
 421
 422         /*
 423          * If this isn't a MIPS32 / MIPS64 compliant CPU.  Config 1 register
 424          * is not supported, we assume R4k style.  Cpu probing already figured
 425          * out the number of tlb entries.
 426          */
 427         if ((c->processor_id & 0xff0000) == PRID_COMP_LEGACY)
 428                 return;
 429 #ifdef CONFIG_MIPS_MT_SMTC
 430         /*
 431          * If TLB is shared in SMTC system, total size already
 432          * has been calculated and written into cpu_data tlbsize
 433          */
 434         if((smtc_status & SMTC_TLB_SHARED) == SMTC_TLB_SHARED)
 435                 return;
 436 #endif /* CONFIG_MIPS_MT_SMTC */
 437
 438         reg = read_c0_config1();
 439         if (!((config >> 7) & 3))
 440                 panic("No TLB present");
 441
 442         c->tlbsize = ((reg >> 25) & 0x3f) + 1;
 443 }
 444
 445 static int __initdata ntlb = 0;
 446 static int __init set_ntlb(char *str)
 447 {
 448         get_option(&str, &ntlb);
 449         return 1;
 450 }
 451
 452 __setup("ntlb=", set_ntlb);
 453
 454 void __init tlb_init(void)
 455 {
 456         unsigned int config = read_c0_config();
 457
 458         /*
 459          * You should never change this register:
 460          *   - On R4600 1.7 the tlbp never hits for pages smaller than
 461          *     the value in the c0_pagemask register.
 462          *   - The entire mm handling assumes the c0_pagemask register to
 463          *     be set for 4kb pages.
 464          */
 465         probe_tlb(config);
 466         write_c0_pagemask(PM_DEFAULT_MASK);
 467         write_c0_wired(0);
 468         write_c0_framemask(0);
 469         temp_tlb_entry = current_cpu_data.tlbsize - 1;
 470
 471         /* From this point on the ARC firmware is dead.  */
 472         local_flush_tlb_all();
 473
 474         /* Did I tell you that ARC SUCKS?  */
 475
 476         if (ntlb) {
 477                 if (ntlb > 1 && ntlb <= current_cpu_data.tlbsize) {
 478                         int wired = current_cpu_data.tlbsize - ntlb;
 479                         write_c0_wired(wired);
 480                         write_c0_index(wired-1);
 481                         printk ("Restricting TLB to %d entries\n", ntlb);
 482                 } else
 483                         printk("Ignoring invalid argument ntlb=%d\n", ntlb);
 484         }
 485
 486         build_tlb_refill_handler();
 487 }