arch/avr32/mm/tlb.c

   1 /*
   2  * AVR32 TLB operations
   3  *
   4  * Copyright (C) 2004-2006 Atmel Corporation
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10 #include <linux/mm.h>
  11
  12 #include <asm/mmu_context.h>
  13
  14 /* TODO: Get the correct number from the CONFIG1 system register */
  15 #define NR_TLB_ENTRIES 32
  16
  17 static void show_dtlb_entry(unsigned int index)
  18 {
  19         u32 tlbehi, tlbehi_save, tlbelo, mmucr, mmucr_save;
  20         unsigned long flags;
  21
  22         local_irq_save(flags);
  23         mmucr_save = sysreg_read(MMUCR);
  24         tlbehi_save = sysreg_read(TLBEHI);
  25         mmucr = SYSREG_BFINS(DRP, index, mmucr_save);
  26         sysreg_write(MMUCR, mmucr);
  27
  28         __builtin_tlbr();
  29         cpu_sync_pipeline();
  30
  31         tlbehi = sysreg_read(TLBEHI);
  32         tlbelo = sysreg_read(TLBELO);
  33
  34         printk("%2u: %c %c %02x   %05x %05x %o  %o  %c %c %c %c\n",
  35                index,
  36                SYSREG_BFEXT(TLBEHI_V, tlbehi) ? '1' : '0',
  37                SYSREG_BFEXT(G, tlbelo) ? '1' : '0',
  38                SYSREG_BFEXT(ASID, tlbehi),
  39                SYSREG_BFEXT(VPN, tlbehi) >> 2,
  40                SYSREG_BFEXT(PFN, tlbelo) >> 2,
  41                SYSREG_BFEXT(AP, tlbelo),
  42                SYSREG_BFEXT(SZ, tlbelo),
  43                SYSREG_BFEXT(TLBELO_C, tlbelo) ? 'C' : ' ',
  44                SYSREG_BFEXT(B, tlbelo) ? 'B' : ' ',
  45                SYSREG_BFEXT(W, tlbelo) ? 'W' : ' ',
  46                SYSREG_BFEXT(TLBELO_D, tlbelo) ? 'D' : ' ');
  47
  48         sysreg_write(MMUCR, mmucr_save);
  49         sysreg_write(TLBEHI, tlbehi_save);
  50         cpu_sync_pipeline();
  51         local_irq_restore(flags);
  52 }
  53
  54 void dump_dtlb(void)
  55 {
  56         unsigned int i;
  57
  58         printk("ID  V G ASID VPN   PFN   AP SZ C B W D\n");
  59         for (i = 0; i < NR_TLB_ENTRIES; i++)
  60                 show_dtlb_entry(i);
  61 }
  62
  63 static void update_dtlb(unsigned long address, pte_t pte)
  64 {
  65         u32 tlbehi;
  66         u32 mmucr;
  67
  68         /*
  69          * We're not changing the ASID here, so no need to flush the
  70          * pipeline.
  71          */
  72         tlbehi = sysreg_read(TLBEHI);
  73         tlbehi = SYSREG_BF(ASID, SYSREG_BFEXT(ASID, tlbehi));
  74         tlbehi |= address & MMU_VPN_MASK;
  75         tlbehi |= SYSREG_BIT(TLBEHI_V);
  76         sysreg_write(TLBEHI, tlbehi);
  77
  78         /* Does this mapping already exist? */
  79         __builtin_tlbs();
  80         mmucr = sysreg_read(MMUCR);
  81
  82         if (mmucr & SYSREG_BIT(MMUCR_N)) {
  83                 /* Not found -- pick a not-recently-accessed entry */
  84                 unsigned int rp;
  85                 u32 tlbar = sysreg_read(TLBARLO);
  86
  87                 rp = 32 - fls(tlbar);
  88                 if (rp == 32) {
  89                         rp = 0;
  90                         sysreg_write(TLBARLO, -1L);
  91                 }
  92
  93                 mmucr = SYSREG_BFINS(DRP, rp, mmucr);
  94                 sysreg_write(MMUCR, mmucr);
  95         }
  96
  97         sysreg_write(TLBELO, pte_val(pte) & _PAGE_FLAGS_HARDWARE_MASK);
  98
  99         /* Let's go */
 100         __builtin_tlbw();
 101 }
 102
 103 void update_mmu_cache(struct vm_area_struct *vma,
 104                       unsigned long address, pte_t *ptep)
 105 {
 106         unsigned long flags;
 107
 108         /* ptrace may call this routine */
 109         if (vma && current->active_mm != vma->vm_mm)
 110                 return;
 111
 112         local_irq_save(flags);
 113         update_dtlb(address, *ptep);
 114         local_irq_restore(flags);
 115 }
 116
 117 static void __flush_tlb_page(unsigned long asid, unsigned long page)
 118 {
 119         u32 mmucr, tlbehi;
 120
 121         /*
 122          * Caller is responsible for masking out non-PFN bits in page
 123          * and changing the current ASID if necessary. This means that
 124          * we don't need to flush the pipeline after writing TLBEHI.
 125          */
 126         tlbehi = page | asid;
 127         sysreg_write(TLBEHI, tlbehi);
 128
 129         __builtin_tlbs();
 130         mmucr = sysreg_read(MMUCR);
 131
 132         if (!(mmucr & SYSREG_BIT(MMUCR_N))) {
 133                 unsigned int entry;
 134                 u32 tlbarlo;
 135
 136                 /* Clear the "valid" bit */
 137                 sysreg_write(TLBEHI, tlbehi);
 138
 139                 /* mark the entry as "not accessed" */
 140                 entry = SYSREG_BFEXT(DRP, mmucr);
 141                 tlbarlo = sysreg_read(TLBARLO);
 142                 tlbarlo |= (0x80000000UL >> entry);
 143                 sysreg_write(TLBARLO, tlbarlo);
 144
 145                 /* update the entry with valid bit clear */
 146                 __builtin_tlbw();
 147         }
 148 }
 149
 150 void flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
 151 {
 152         if (vma->vm_mm && vma->vm_mm->context != NO_CONTEXT) {
 153                 unsigned long flags, asid;
 154                 unsigned long saved_asid = MMU_NO_ASID;
 155
 156                 asid = vma->vm_mm->context & MMU_CONTEXT_ASID_MASK;
 157                 page &= PAGE_MASK;
 158
 159                 local_irq_save(flags);
 160                 if (vma->vm_mm != current->mm) {
 161                         saved_asid = get_asid();
 162                         set_asid(asid);
 163                 }
 164
 165                 __flush_tlb_page(asid, page);
 166
 167                 if (saved_asid != MMU_NO_ASID)
 168                         set_asid(saved_asid);
 169                 local_irq_restore(flags);
 170         }
 171 }
 172
 173 void flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
 174                      unsigned long end)
 175 {
 176         struct mm_struct *mm = vma->vm_mm;
 177
 178         if (mm->context != NO_CONTEXT) {
 179                 unsigned long flags;
 180                 int size;
 181
 182                 local_irq_save(flags);
 183                 size = (end - start + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
 184
 185                 if (size > (MMU_DTLB_ENTRIES / 4)) { /* Too many entries to flush */
 186                         mm->context = NO_CONTEXT;
 187                         if (mm == current->mm)
 188                                 activate_context(mm);
 189                 } else {
 190                         unsigned long asid;
 191                         unsigned long saved_asid;
 192
 193                         asid = mm->context & MMU_CONTEXT_ASID_MASK;
 194                         saved_asid = MMU_NO_ASID;
 195
 196                         start &= PAGE_MASK;
 197                         end += (PAGE_SIZE - 1);
 198                         end &= PAGE_MASK;
 199
 200                         if (mm != current->mm) {
 201                                 saved_asid = get_asid();
 202                                 set_asid(asid);
 203                         }
 204
 205                         while (start < end) {
 206                                 __flush_tlb_page(asid, start);
 207                                 start += PAGE_SIZE;
 208                         }
 209                         if (saved_asid != MMU_NO_ASID)
 210                                 set_asid(saved_asid);
 211                 }
 212                 local_irq_restore(flags);
 213         }
 214 }
 215
 216 /*
 217  * This function depends on the pages to be flushed having the G
 218  * (global) bit set in their pte. This is true for all
 219  * PAGE_KERNEL(_RO) pages.
 220  */
 221 void flush_tlb_kernel_range(unsigned long start, unsigned long end)
 222 {
 223         unsigned long flags;
 224         int size;
 225
 226         size = (end - start + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
 227         if (size > (MMU_DTLB_ENTRIES / 4)) { /* Too many entries to flush */
 228                 flush_tlb_all();
 229         } else {
 230                 unsigned long asid;
 231
 232                 local_irq_save(flags);
 233                 asid = get_asid();
 234
 235                 start &= PAGE_MASK;
 236                 end += (PAGE_SIZE - 1);
 237                 end &= PAGE_MASK;
 238
 239                 while (start < end) {
 240                         __flush_tlb_page(asid, start);
 241                         start += PAGE_SIZE;
 242                 }
 243                 local_irq_restore(flags);
 244         }
 245 }
 246
 247 void flush_tlb_mm(struct mm_struct *mm)
 248 {
 249         /* Invalidate all TLB entries of this process by getting a new ASID */
 250         if (mm->context != NO_CONTEXT) {
 251                 unsigned long flags;
 252
 253                 local_irq_save(flags);
 254                 mm->context = NO_CONTEXT;
 255                 if (mm == current->mm)
 256                         activate_context(mm);
 257                 local_irq_restore(flags);
 258         }
 259 }
 260
 261 void flush_tlb_all(void)
 262 {
 263         unsigned long flags;
 264
 265         local_irq_save(flags);
 266         sysreg_write(MMUCR, sysreg_read(MMUCR) | SYSREG_BIT(MMUCR_I));
 267         local_irq_restore(flags);
 268 }
 269
 270 #ifdef CONFIG_PROC_FS
 271
 272 #include <linux/seq_file.h>
 273 #include <linux/proc_fs.h>
 274 #include <linux/init.h>
 275
 276 static void *tlb_start(struct seq_file *tlb, loff_t *pos)
 277 {
 278         static unsigned long tlb_index;
 279
 280         if (*pos >= NR_TLB_ENTRIES)
 281                 return NULL;
 282
 283         tlb_index = 0;
 284         return &tlb_index;
 285 }
 286
 287 static void *tlb_next(struct seq_file *tlb, void *v, loff_t *pos)
 288 {
 289         unsigned long *index = v;
 290
 291         if (*index >= NR_TLB_ENTRIES - 1)
 292                 return NULL;
 293
 294         ++*pos;
 295         ++*index;
 296         return index;
 297 }
 298
 299 static void tlb_stop(struct seq_file *tlb, void *v)
 300 {
 301
 302 }
 303
 304 static int tlb_show(struct seq_file *tlb, void *v)
 305 {
 306         unsigned int tlbehi, tlbehi_save, tlbelo, mmucr, mmucr_save;
 307         unsigned long flags;
 308         unsigned long *index = v;
 309
 310         if (*index == 0)
 311                 seq_puts(tlb, "ID  V G ASID VPN   PFN   AP SZ C B W D\n");
 312
 313         BUG_ON(*index >= NR_TLB_ENTRIES);
 314
 315         local_irq_save(flags);
 316         mmucr_save = sysreg_read(MMUCR);
 317         tlbehi_save = sysreg_read(TLBEHI);
 318         mmucr = SYSREG_BFINS(DRP, *index, mmucr_save);
 319         sysreg_write(MMUCR, mmucr);
 320
 321         /* TLBR might change the ASID */
 322         __builtin_tlbr();
 323         cpu_sync_pipeline();
 324
 325         tlbehi = sysreg_read(TLBEHI);
 326         tlbelo = sysreg_read(TLBELO);
 327
 328         sysreg_write(MMUCR, mmucr_save);
 329         sysreg_write(TLBEHI, tlbehi_save);
 330         cpu_sync_pipeline();
 331         local_irq_restore(flags);
 332
 333         seq_printf(tlb, "%2lu: %c %c %02x   %05x %05x %o  %o  %c %c %c %c\n",
 334                    *index,
 335                    SYSREG_BFEXT(TLBEHI_V, tlbehi) ? '1' : '0',
 336                    SYSREG_BFEXT(G, tlbelo) ? '1' : '0',
 337                    SYSREG_BFEXT(ASID, tlbehi),
 338                    SYSREG_BFEXT(VPN, tlbehi) >> 2,
 339                    SYSREG_BFEXT(PFN, tlbelo) >> 2,
 340                    SYSREG_BFEXT(AP, tlbelo),
 341                    SYSREG_BFEXT(SZ, tlbelo),
 342                    SYSREG_BFEXT(TLBELO_C, tlbelo) ? '1' : '0',
 343                    SYSREG_BFEXT(B, tlbelo) ? '1' : '0',
 344                    SYSREG_BFEXT(W, tlbelo) ? '1' : '0',
 345                    SYSREG_BFEXT(TLBELO_D, tlbelo) ? '1' : '0');
 346
 347         return 0;
 348 }
 349
 350 static const struct seq_operations tlb_ops = {
 351         .start          = tlb_start,
 352         .next           = tlb_next,
 353         .stop           = tlb_stop,
 354         .show           = tlb_show,
 355 };
 356
 357 static int tlb_open(struct inode *inode, struct file *file)
 358 {
 359         return seq_open(file, &tlb_ops);
 360 }
 361
 362 static const struct file_operations proc_tlb_operations = {
 363         .open           = tlb_open,
 364         .read           = seq_read,
 365         .llseek         = seq_lseek,
 366         .release        = seq_release,
 367 };
 368
 369 static int __init proctlb_init(void)
 370 {
 371         proc_create("tlb", 0, NULL, &proc_tlb_operations);
 372         return 0;
 373 }
 374 late_initcall(proctlb_init);
 375 #endif /* CONFIG_PROC_FS */