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