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