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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 /* CP0 hazard avoidance. */
  25 #define BARRIER __asm__ __volatile__(".set noreorder\n\t" \
  26                                      "nop; nop; nop; nop; nop; nop;\n\t" \
  27                                      ".set reorder\n\t")
  28
  29 void local_flush_tlb_all(void)
  30 {
  31         unsigned long flags;
  32         unsigned long old_ctx;
  33         int entry;
  34
  35         local_irq_save(flags);
  36         /* Save old context and create impossible VPN2 value */
  37         old_ctx = read_c0_entryhi();
  38         write_c0_entrylo0(0);
  39         write_c0_entrylo1(0);
  40
  41         entry = read_c0_wired();
  42
  43         /* Blast 'em all away. */
  44         while (entry < current_cpu_data.tlbsize) {
  45                 /*
  46                  * Make sure all entries differ.  If they're not different
  47                  * MIPS32 will take revenge ...
  48                  */
  49                 write_c0_entryhi(CKSEG0 + (entry << (PAGE_SHIFT + 1)));
  50                 write_c0_index(entry);
  51                 mtc0_tlbw_hazard();
  52                 tlb_write_indexed();
  53                 entry++;
  54         }
  55         tlbw_use_hazard();
  56         write_c0_entryhi(old_ctx);
  57         local_irq_restore(flags);
  58 }
  59
  60 void local_flush_tlb_mm(struct mm_struct *mm)
  61 {
  62         int cpu = smp_processor_id();
  63
  64         if (cpu_context(cpu, mm) != 0)
  65                 drop_mmu_context(mm,cpu);
  66 }
  67
  68 void local_flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
  69         unsigned long end)
  70 {
  71         struct mm_struct *mm = vma->vm_mm;
  72         int cpu = smp_processor_id();
  73
  74         if (cpu_context(cpu, mm) != 0) {
  75                 unsigned long flags;
  76                 int size;
  77
  78                 local_irq_save(flags);
  79                 size = (end - start + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
  80                 size = (size + 1) >> 1;
  81                 if (size <= current_cpu_data.tlbsize/2) {
  82                         int oldpid = read_c0_entryhi();
  83                         int newpid = cpu_asid(cpu, mm);
  84
  85                         start &= (PAGE_MASK << 1);
  86                         end += ((PAGE_SIZE << 1) - 1);
  87                         end &= (PAGE_MASK << 1);
  88                         while (start < end) {
  89                                 int idx;
  90
  91                                 write_c0_entryhi(start | newpid);
  92                                 start += (PAGE_SIZE << 1);
  93                                 mtc0_tlbw_hazard();
  94                                 tlb_probe();
  95                                 BARRIER;
  96                                 idx = read_c0_index();
  97                                 write_c0_entrylo0(0);
  98                                 write_c0_entrylo1(0);
  99                                 if (idx < 0)
 100                                         continue;
 101                                 /* Make sure all entries differ. */
 102                                 write_c0_entryhi(CKSEG0 +
 103                                                  (idx << (PAGE_SHIFT + 1)));
 104                                 mtc0_tlbw_hazard();
 105                                 tlb_write_indexed();
 106                         }
 107                         tlbw_use_hazard();
 108                         write_c0_entryhi(oldpid);
 109                 } else {
 110                         drop_mmu_context(mm, cpu);
 111                 }
 112                 local_irq_restore(flags);
 113         }
 114 }
 115
 116 void local_flush_tlb_kernel_range(unsigned long start, unsigned long end)
 117 {
 118         unsigned long flags;
 119         int size;
 120
 121         local_irq_save(flags);
 122         size = (end - start + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
 123         size = (size + 1) >> 1;
 124         if (size <= current_cpu_data.tlbsize / 2) {
 125                 int pid = read_c0_entryhi();
 126
 127                 start &= (PAGE_MASK << 1);
 128                 end += ((PAGE_SIZE << 1) - 1);
 129                 end &= (PAGE_MASK << 1);
 130
 131                 while (start < end) {
 132                         int idx;
 133
 134                         write_c0_entryhi(start);
 135                         start += (PAGE_SIZE << 1);
 136                         mtc0_tlbw_hazard();
 137                         tlb_probe();
 138                         BARRIER;
 139                         idx = read_c0_index();
 140                         write_c0_entrylo0(0);
 141                         write_c0_entrylo1(0);
 142                         if (idx < 0)
 143                                 continue;
 144                         /* Make sure all entries differ. */
 145                         write_c0_entryhi(CKSEG0 + (idx << (PAGE_SHIFT + 1)));
 146                         mtc0_tlbw_hazard();
 147                         tlb_write_indexed();
 148                 }
 149                 tlbw_use_hazard();
 150                 write_c0_entryhi(pid);
 151         } else {
 152                 local_flush_tlb_all();
 153         }
 154         local_irq_restore(flags);
 155 }
 156
 157 void local_flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
 158 {
 159         int cpu = smp_processor_id();
 160
 161         if (cpu_context(cpu, vma->vm_mm) != 0) {
 162                 unsigned long flags;
 163                 int oldpid, newpid, idx;
 164
 165                 newpid = cpu_asid(cpu, vma->vm_mm);
 166                 page &= (PAGE_MASK << 1);
 167                 local_irq_save(flags);
 168                 oldpid = read_c0_entryhi();
 169                 write_c0_entryhi(page | newpid);
 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                         goto finish;
 178                 /* Make sure all entries differ. */
 179                 write_c0_entryhi(CKSEG0 + (idx << (PAGE_SHIFT + 1)));
 180                 mtc0_tlbw_hazard();
 181                 tlb_write_indexed();
 182                 tlbw_use_hazard();
 183
 184         finish:
 185                 write_c0_entryhi(oldpid);
 186                 local_irq_restore(flags);
 187         }
 188 }
 189
 190 /*
 191  * This one is only used for pages with the global bit set so we don't care
 192  * much about the ASID.
 193  */
 194 void local_flush_tlb_one(unsigned long page)
 195 {
 196         unsigned long flags;
 197         int oldpid, idx;
 198
 199         local_irq_save(flags);
 200         page &= (PAGE_MASK << 1);
 201         oldpid = read_c0_entryhi();
 202         write_c0_entryhi(page);
 203         mtc0_tlbw_hazard();
 204         tlb_probe();
 205         BARRIER;
 206         idx = read_c0_index();
 207         write_c0_entrylo0(0);
 208         write_c0_entrylo1(0);
 209         if (idx >= 0) {
 210                 /* Make sure all entries differ. */
 211                 write_c0_entryhi(CKSEG0 + (idx << (PAGE_SHIFT + 1)));
 212                 mtc0_tlbw_hazard();
 213                 tlb_write_indexed();
 214                 tlbw_use_hazard();
 215         }
 216         write_c0_entryhi(oldpid);
 217
 218         local_irq_restore(flags);
 219 }
 220
 221 /*
 222  * We will need multiple versions of update_mmu_cache(), one that just
 223  * updates the TLB with the new pte(s), and another which also checks
 224  * for the R4k "end of page" hardware bug and does the needy.
 225  */
 226 void __update_tlb(struct vm_area_struct * vma, unsigned long address, pte_t pte)
 227 {
 228         unsigned long flags;
 229         pgd_t *pgdp;
 230         pmd_t *pmdp;
 231         pte_t *ptep;
 232         int idx, pid;
 233
 234         /*
 235          * Handle debugger faulting in for debugee.
 236          */
 237         if (current->active_mm != vma->vm_mm)
 238                 return;
 239
 240         pid = read_c0_entryhi() & ASID_MASK;
 241
 242         local_irq_save(flags);
 243         address &= (PAGE_MASK << 1);
 244         write_c0_entryhi(address | pid);
 245         pgdp = pgd_offset(vma->vm_mm, address);
 246         mtc0_tlbw_hazard();
 247         tlb_probe();
 248         BARRIER;
 249         pmdp = pmd_offset(pgdp, address);
 250         idx = read_c0_index();
 251         ptep = pte_offset_map(pmdp, address);
 252
 253  #if defined(CONFIG_64BIT_PHYS_ADDR) && defined(CONFIG_CPU_MIPS32)
 254         write_c0_entrylo0(ptep->pte_high);
 255         ptep++;
 256         write_c0_entrylo1(ptep->pte_high);
 257 #else
 258         write_c0_entrylo0(pte_val(*ptep++) >> 6);
 259         write_c0_entrylo1(pte_val(*ptep) >> 6);
 260 #endif
 261         write_c0_entryhi(address | pid);
 262         mtc0_tlbw_hazard();
 263         if (idx < 0)
 264                 tlb_write_random();
 265         else
 266                 tlb_write_indexed();
 267         tlbw_use_hazard();
 268         write_c0_entryhi(pid);
 269         local_irq_restore(flags);
 270 }
 271
 272 #if 0
 273 static void r4k_update_mmu_cache_hwbug(struct vm_area_struct * vma,
 274                                        unsigned long address, pte_t pte)
 275 {
 276         unsigned long flags;
 277         unsigned int asid;
 278         pgd_t *pgdp;
 279         pmd_t *pmdp;
 280         pte_t *ptep;
 281         int idx;
 282
 283         local_irq_save(flags);
 284         address &= (PAGE_MASK << 1);
 285         asid = read_c0_entryhi() & ASID_MASK;
 286         write_c0_entryhi(address | asid);
 287         pgdp = pgd_offset(vma->vm_mm, address);
 288         mtc0_tlbw_hazard();
 289         tlb_probe();
 290         BARRIER;
 291         pmdp = pmd_offset(pgdp, address);
 292         idx = read_c0_index();
 293         ptep = pte_offset_map(pmdp, address);
 294         write_c0_entrylo0(pte_val(*ptep++) >> 6);
 295         write_c0_entrylo1(pte_val(*ptep) >> 6);
 296         mtc0_tlbw_hazard();
 297         if (idx < 0)
 298                 tlb_write_random();
 299         else
 300                 tlb_write_indexed();
 301         tlbw_use_hazard();
 302         local_irq_restore(flags);
 303 }
 304 #endif
 305
 306 void __init add_wired_entry(unsigned long entrylo0, unsigned long entrylo1,
 307         unsigned long entryhi, unsigned long pagemask)
 308 {
 309         unsigned long flags;
 310         unsigned long wired;
 311         unsigned long old_pagemask;
 312         unsigned long old_ctx;
 313
 314         local_irq_save(flags);
 315         /* Save old context and create impossible VPN2 value */
 316         old_ctx = read_c0_entryhi();
 317         old_pagemask = read_c0_pagemask();
 318         wired = read_c0_wired();
 319         write_c0_wired(wired + 1);
 320         write_c0_index(wired);
 321         BARRIER;
 322         write_c0_pagemask(pagemask);
 323         write_c0_entryhi(entryhi);
 324         write_c0_entrylo0(entrylo0);
 325         write_c0_entrylo1(entrylo1);
 326         mtc0_tlbw_hazard();
 327         tlb_write_indexed();
 328         tlbw_use_hazard();
 329
 330         write_c0_entryhi(old_ctx);
 331         BARRIER;
 332         write_c0_pagemask(old_pagemask);
 333         local_flush_tlb_all();
 334         local_irq_restore(flags);
 335 }
 336
 337 /*
 338  * Used for loading TLB entries before trap_init() has started, when we
 339  * don't actually want to add a wired entry which remains throughout the
 340  * lifetime of the system
 341  */
 342
 343 static int temp_tlb_entry __initdata;
 344
 345 __init int add_temporary_entry(unsigned long entrylo0, unsigned long entrylo1,
 346                                unsigned long entryhi, unsigned long pagemask)
 347 {
 348         int ret = 0;
 349         unsigned long flags;
 350         unsigned long wired;
 351         unsigned long old_pagemask;
 352         unsigned long old_ctx;
 353
 354         local_irq_save(flags);
 355         /* Save old context and create impossible VPN2 value */
 356         old_ctx = read_c0_entryhi();
 357         old_pagemask = read_c0_pagemask();
 358         wired = read_c0_wired();
 359         if (--temp_tlb_entry < wired) {
 360                 printk(KERN_WARNING "No TLB space left for add_temporary_entry\n");
 361                 ret = -ENOSPC;
 362                 goto out;
 363         }
 364
 365         write_c0_index(temp_tlb_entry);
 366         write_c0_pagemask(pagemask);
 367         write_c0_entryhi(entryhi);
 368         write_c0_entrylo0(entrylo0);
 369         write_c0_entrylo1(entrylo1);
 370         mtc0_tlbw_hazard();
 371         tlb_write_indexed();
 372         tlbw_use_hazard();
 373
 374         write_c0_entryhi(old_ctx);
 375         write_c0_pagemask(old_pagemask);
 376 out:
 377         local_irq_restore(flags);
 378         return ret;
 379 }
 380
 381 static void __init probe_tlb(unsigned long config)
 382 {
 383         struct cpuinfo_mips *c = &current_cpu_data;
 384         unsigned int reg;
 385
 386         /*
 387          * If this isn't a MIPS32 / MIPS64 compliant CPU.  Config 1 register
 388          * is not supported, we assume R4k style.  Cpu probing already figured
 389          * out the number of tlb entries.
 390          */
 391         if ((c->processor_id  & 0xff0000) == PRID_COMP_LEGACY)
 392                 return;
 393
 394         reg = read_c0_config1();
 395         if (!((config >> 7) & 3))
 396                 panic("No TLB present");
 397
 398         c->tlbsize = ((reg >> 25) & 0x3f) + 1;
 399 }
 400
 401 void __init tlb_init(void)
 402 {
 403         unsigned int config = read_c0_config();
 404
 405         /*
 406          * You should never change this register:
 407          *   - On R4600 1.7 the tlbp never hits for pages smaller than
 408          *     the value in the c0_pagemask register.
 409          *   - The entire mm handling assumes the c0_pagemask register to
 410          *     be set for 4kb pages.
 411          */
 412         probe_tlb(config);
 413         write_c0_pagemask(PM_DEFAULT_MASK);
 414         write_c0_wired(0);
 415         temp_tlb_entry = current_cpu_data.tlbsize - 1;
 416         local_flush_tlb_all();
 417
 418         build_tlb_refill_handler();
 419 }