arch/arm64/mm/dump.c

   1 /*
   2  * Copyright (c) 2014, The Linux Foundation. All rights reserved.
   3  * Debug helper to dump the current kernel pagetables of the system
   4  * so that we can see what the various memory ranges are set to.
   5  *
   6  * Derived from x86 and arm implementation:
   7  * (C) Copyright 2008 Intel Corporation
   8  *
   9  * Author: Arjan van de Ven <arjan@linux.intel.com>
  10  *
  11  * This program is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU General Public License
  13  * as published by the Free Software Foundation; version 2
  14  * of the License.
  15  */
  16 #include <linux/debugfs.h>
  17 #include <linux/errno.h>
  18 #include <linux/fs.h>
  19 #include <linux/io.h>
  20 #include <linux/init.h>
  21 #include <linux/mm.h>
  22 #include <linux/sched.h>
  23 #include <linux/seq_file.h>
  24
  25 #include <asm/fixmap.h>
  26 #include <asm/memory.h>
  27 #include <asm/pgtable.h>
  28 #include <asm/pgtable-hwdef.h>
  29
  30 #define LOWEST_ADDR     (UL(0xffffffffffffffff) << VA_BITS)
  31
  32 struct addr_marker {
  33         unsigned long start_address;
  34         const char *name;
  35 };
  36
  37 enum address_markers_idx {
  38         MODULES_START_NR = 0,
  39         MODULES_END_NR,
  40         VMALLOC_START_NR,
  41         VMALLOC_END_NR,
  42 #ifdef CONFIG_SPARSEMEM_VMEMMAP
  43         VMEMMAP_START_NR,
  44         VMEMMAP_END_NR,
  45 #endif
  46         FIXADDR_START_NR,
  47         FIXADDR_END_NR,
  48         PCI_START_NR,
  49         PCI_END_NR,
  50         KERNEL_SPACE_NR,
  51 };
  52
  53 static struct addr_marker address_markers[] = {
  54         { MODULES_VADDR,        "Modules start" },
  55         { MODULES_END,          "Modules end" },
  56         { VMALLOC_START,        "vmalloc() Area" },
  57         { VMALLOC_END,          "vmalloc() End" },
  58 #ifdef CONFIG_SPARSEMEM_VMEMMAP
  59         { 0,                    "vmemmap start" },
  60         { 0,                    "vmemmap end" },
  61 #endif
  62         { FIXADDR_START,        "Fixmap start" },
  63         { FIXADDR_TOP,          "Fixmap end" },
  64         { PCI_IO_START,         "PCI I/O start" },
  65         { PCI_IO_END,           "PCI I/O end" },
  66         { PAGE_OFFSET,          "Linear Mapping" },
  67         { -1,                   NULL },
  68 };
  69
  70 /*
  71  * The page dumper groups page table entries of the same type into a single
  72  * description. It uses pg_state to track the range information while
  73  * iterating over the pte entries. When the continuity is broken it then
  74  * dumps out a description of the range.
  75  */
  76 struct pg_state {
  77         struct seq_file *seq;
  78         const struct addr_marker *marker;
  79         unsigned long start_address;
  80         unsigned level;
  81         u64 current_prot;
  82 };
  83
  84 struct prot_bits {
  85         u64             mask;
  86         u64             val;
  87         const char      *set;
  88         const char      *clear;
  89 };
  90
  91 static const struct prot_bits pte_bits[] = {
  92         {
  93                 .mask   = PTE_VALID,
  94                 .val    = PTE_VALID,
  95                 .set    = " ",
  96                 .clear  = "F",
  97         }, {
  98                 .mask   = PTE_USER,
  99                 .val    = PTE_USER,
 100                 .set    = "USR",
 101                 .clear  = "   ",
 102         }, {
 103                 .mask   = PTE_RDONLY,
 104                 .val    = PTE_RDONLY,
 105                 .set    = "ro",
 106                 .clear  = "RW",
 107         }, {
 108                 .mask   = PTE_PXN,
 109                 .val    = PTE_PXN,
 110                 .set    = "NX",
 111                 .clear  = "x ",
 112         }, {
 113                 .mask   = PTE_SHARED,
 114                 .val    = PTE_SHARED,
 115                 .set    = "SHD",
 116                 .clear  = "   ",
 117         }, {
 118                 .mask   = PTE_AF,
 119                 .val    = PTE_AF,
 120                 .set    = "AF",
 121                 .clear  = "  ",
 122         }, {
 123                 .mask   = PTE_NG,
 124                 .val    = PTE_NG,
 125                 .set    = "NG",
 126                 .clear  = "  ",
 127         }, {
 128                 .mask   = PTE_CONT,
 129                 .val    = PTE_CONT,
 130                 .set    = "CON",
 131                 .clear  = "   ",
 132         }, {
 133                 .mask   = PTE_TABLE_BIT,
 134                 .val    = PTE_TABLE_BIT,
 135                 .set    = "   ",
 136                 .clear  = "BLK",
 137         }, {
 138                 .mask   = PTE_UXN,
 139                 .val    = PTE_UXN,
 140                 .set    = "UXN",
 141         }, {
 142                 .mask   = PTE_ATTRINDX_MASK,
 143                 .val    = PTE_ATTRINDX(MT_DEVICE_nGnRnE),
 144                 .set    = "DEVICE/nGnRnE",
 145         }, {
 146                 .mask   = PTE_ATTRINDX_MASK,
 147                 .val    = PTE_ATTRINDX(MT_DEVICE_nGnRE),
 148                 .set    = "DEVICE/nGnRE",
 149         }, {
 150                 .mask   = PTE_ATTRINDX_MASK,
 151                 .val    = PTE_ATTRINDX(MT_DEVICE_GRE),
 152                 .set    = "DEVICE/GRE",
 153         }, {
 154                 .mask   = PTE_ATTRINDX_MASK,
 155                 .val    = PTE_ATTRINDX(MT_NORMAL_NC),
 156                 .set    = "MEM/NORMAL-NC",
 157         }, {
 158                 .mask   = PTE_ATTRINDX_MASK,
 159                 .val    = PTE_ATTRINDX(MT_NORMAL),
 160                 .set    = "MEM/NORMAL",
 161         }
 162 };
 163
 164 struct pg_level {
 165         const struct prot_bits *bits;
 166         size_t num;
 167         u64 mask;
 168 };
 169
 170 static struct pg_level pg_level[] = {
 171         {
 172         }, { /* pgd */
 173                 .bits   = pte_bits,
 174                 .num    = ARRAY_SIZE(pte_bits),
 175         }, { /* pud */
 176                 .bits   = pte_bits,
 177                 .num    = ARRAY_SIZE(pte_bits),
 178         }, { /* pmd */
 179                 .bits   = pte_bits,
 180                 .num    = ARRAY_SIZE(pte_bits),
 181         }, { /* pte */
 182                 .bits   = pte_bits,
 183                 .num    = ARRAY_SIZE(pte_bits),
 184         },
 185 };
 186
 187 static void dump_prot(struct pg_state *st, const struct prot_bits *bits,
 188                         size_t num)
 189 {
 190         unsigned i;
 191
 192         for (i = 0; i < num; i++, bits++) {
 193                 const char *s;
 194
 195                 if ((st->current_prot & bits->mask) == bits->val)
 196                         s = bits->set;
 197                 else
 198                         s = bits->clear;
 199
 200                 if (s)
 201                         seq_printf(st->seq, " %s", s);
 202         }
 203 }
 204
 205 static void note_page(struct pg_state *st, unsigned long addr, unsigned level,
 206                                 u64 val)
 207 {
 208         static const char units[] = "KMGTPE";
 209         u64 prot = val & pg_level[level].mask;
 210
 211         if (!st->level) {
 212                 st->level = level;
 213                 st->current_prot = prot;
 214                 st->start_address = addr;
 215                 seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
 216         } else if (prot != st->current_prot || level != st->level ||
 217                    addr >= st->marker[1].start_address) {
 218                 const char *unit = units;
 219                 unsigned long delta;
 220
 221                 if (st->current_prot) {
 222                         seq_printf(st->seq, "0x%016lx-0x%016lx   ",
 223                                    st->start_address, addr);
 224
 225                         delta = (addr - st->start_address) >> 10;
 226                         while (!(delta & 1023) && unit[1]) {
 227                                 delta >>= 10;
 228                                 unit++;
 229                         }
 230                         seq_printf(st->seq, "%9lu%c", delta, *unit);
 231                         if (pg_level[st->level].bits)
 232                                 dump_prot(st, pg_level[st->level].bits,
 233                                           pg_level[st->level].num);
 234                         seq_puts(st->seq, "\n");
 235                 }
 236
 237                 if (addr >= st->marker[1].start_address) {
 238                         st->marker++;
 239                         seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
 240                 }
 241
 242                 st->start_address = addr;
 243                 st->current_prot = prot;
 244                 st->level = level;
 245         }
 246
 247         if (addr >= st->marker[1].start_address) {
 248                 st->marker++;
 249                 seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
 250         }
 251
 252 }
 253
 254 static void walk_pte(struct pg_state *st, pmd_t *pmd, unsigned long start)
 255 {
 256         pte_t *pte = pte_offset_kernel(pmd, 0);
 257         unsigned long addr;
 258         unsigned i;
 259
 260         for (i = 0; i < PTRS_PER_PTE; i++, pte++) {
 261                 addr = start + i * PAGE_SIZE;
 262                 note_page(st, addr, 4, pte_val(*pte));
 263         }
 264 }
 265
 266 static void walk_pmd(struct pg_state *st, pud_t *pud, unsigned long start)
 267 {
 268         pmd_t *pmd = pmd_offset(pud, 0);
 269         unsigned long addr;
 270         unsigned i;
 271
 272         for (i = 0; i < PTRS_PER_PMD; i++, pmd++) {
 273                 addr = start + i * PMD_SIZE;
 274                 if (pmd_none(*pmd) || pmd_sect(*pmd)) {
 275                         note_page(st, addr, 3, pmd_val(*pmd));
 276                 } else {
 277                         BUG_ON(pmd_bad(*pmd));
 278                         walk_pte(st, pmd, addr);
 279                 }
 280         }
 281 }
 282
 283 static void walk_pud(struct pg_state *st, pgd_t *pgd, unsigned long start)
 284 {
 285         pud_t *pud = pud_offset(pgd, 0);
 286         unsigned long addr;
 287         unsigned i;
 288
 289         for (i = 0; i < PTRS_PER_PUD; i++, pud++) {
 290                 addr = start + i * PUD_SIZE;
 291                 if (pud_none(*pud) || pud_sect(*pud)) {
 292                         note_page(st, addr, 2, pud_val(*pud));
 293                 } else {
 294                         BUG_ON(pud_bad(*pud));
 295                         walk_pmd(st, pud, addr);
 296                 }
 297         }
 298 }
 299
 300 static void walk_pgd(struct pg_state *st, struct mm_struct *mm, unsigned long start)
 301 {
 302         pgd_t *pgd = pgd_offset(mm, 0UL);
 303         unsigned i;
 304         unsigned long addr;
 305
 306         for (i = 0; i < PTRS_PER_PGD; i++, pgd++) {
 307                 addr = start + i * PGDIR_SIZE;
 308                 if (pgd_none(*pgd)) {
 309                         note_page(st, addr, 1, pgd_val(*pgd));
 310                 } else {
 311                         BUG_ON(pgd_bad(*pgd));
 312                         walk_pud(st, pgd, addr);
 313                 }
 314         }
 315 }
 316
 317 static int ptdump_show(struct seq_file *m, void *v)
 318 {
 319         struct pg_state st = {
 320                 .seq = m,
 321                 .marker = address_markers,
 322         };
 323
 324         walk_pgd(&st, &init_mm, LOWEST_ADDR);
 325
 326         note_page(&st, 0, 0, 0);
 327         return 0;
 328 }
 329
 330 static int ptdump_open(struct inode *inode, struct file *file)
 331 {
 332         return single_open(file, ptdump_show, NULL);
 333 }
 334
 335 static const struct file_operations ptdump_fops = {
 336         .open           = ptdump_open,
 337         .read           = seq_read,
 338         .llseek         = seq_lseek,
 339         .release        = single_release,
 340 };
 341
 342 static int ptdump_init(void)
 343 {
 344         struct dentry *pe;
 345         unsigned i, j;
 346
 347         for (i = 0; i < ARRAY_SIZE(pg_level); i++)
 348                 if (pg_level[i].bits)
 349                         for (j = 0; j < pg_level[i].num; j++)
 350                                 pg_level[i].mask |= pg_level[i].bits[j].mask;
 351
 352 #ifdef CONFIG_SPARSEMEM_VMEMMAP
 353         address_markers[VMEMMAP_START_NR].start_address =
 354                                 (unsigned long)virt_to_page(PAGE_OFFSET);
 355         address_markers[VMEMMAP_END_NR].start_address =
 356                                 (unsigned long)virt_to_page(high_memory);
 357 #endif
 358
 359         pe = debugfs_create_file("kernel_page_tables", 0400, NULL, NULL,
 360                                  &ptdump_fops);
 361         return pe ? 0 : -ENOMEM;
 362 }
 363 device_initcall(ptdump_init);