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/init.h>
  20 #include <linux/mm.h>
  21 #include <linux/sched.h>
  22 #include <linux/seq_file.h>
  23
  24 #include <asm/fixmap.h>
  25 #include <asm/memory.h>
  26 #include <asm/pgtable.h>
  27 #include <asm/pgtable-hwdef.h>
  28
  29 #define LOWEST_ADDR     (UL(0xffffffffffffffff) << VA_BITS)
  30
  31 struct addr_marker {
  32         unsigned long start_address;
  33         const char *name;
  34 };
  35
  36 enum address_markers_idx {
  37         VMALLOC_START_NR = 0,
  38         VMALLOC_END_NR,
  39 #ifdef CONFIG_SPARSEMEM_VMEMMAP
  40         VMEMMAP_START_NR,
  41         VMEMMAP_END_NR,
  42 #endif
  43         FIXADDR_START_NR,
  44         FIXADDR_END_NR,
  45         PCI_START_NR,
  46         PCI_END_NR,
  47         MODULES_START_NR,
  48         MODUELS_END_NR,
  49         KERNEL_SPACE_NR,
  50 };
  51
  52 static struct addr_marker address_markers[] = {
  53         { VMALLOC_START,        "vmalloc() Area" },
  54         { VMALLOC_END,          "vmalloc() End" },
  55 #ifdef CONFIG_SPARSEMEM_VMEMMAP
  56         { 0,                    "vmemmap start" },
  57         { 0,                    "vmemmap end" },
  58 #endif
  59         { FIXADDR_START,        "Fixmap start" },
  60         { FIXADDR_TOP,          "Fixmap end" },
  61         { PCI_IO_START,         "PCI I/O start" },
  62         { PCI_IO_END,           "PCI I/O end" },
  63         { MODULES_VADDR,        "Modules start" },
  64         { MODULES_END,          "Modules end" },
  65         { PAGE_OFFSET,          "Kernel Mapping" },
  66         { -1,                   NULL },
  67 };
  68
  69 struct pg_state {
  70         struct seq_file *seq;
  71         const struct addr_marker *marker;
  72         unsigned long start_address;
  73         unsigned level;
  74         u64 current_prot;
  75 };
  76
  77 struct prot_bits {
  78         u64             mask;
  79         u64             val;
  80         const char      *set;
  81         const char      *clear;
  82 };
  83
  84 static const struct prot_bits pte_bits[] = {
  85         {
  86                 .mask   = PTE_USER,
  87                 .val    = PTE_USER,
  88                 .set    = "USR",
  89                 .clear  = "   ",
  90         }, {
  91                 .mask   = PTE_RDONLY,
  92                 .val    = PTE_RDONLY,
  93                 .set    = "ro",
  94                 .clear  = "RW",
  95         }, {
  96                 .mask   = PTE_PXN,
  97                 .val    = PTE_PXN,
  98                 .set    = "NX",
  99                 .clear  = "x ",
 100         }, {
 101                 .mask   = PTE_SHARED,
 102                 .val    = PTE_SHARED,
 103                 .set    = "SHD",
 104                 .clear  = "   ",
 105         }, {
 106                 .mask   = PTE_AF,
 107                 .val    = PTE_AF,
 108                 .set    = "AF",
 109                 .clear  = "  ",
 110         }, {
 111                 .mask   = PTE_NG,
 112                 .val    = PTE_NG,
 113                 .set    = "NG",
 114                 .clear  = "  ",
 115         }, {
 116                 .mask   = PTE_UXN,
 117                 .val    = PTE_UXN,
 118                 .set    = "UXN",
 119         }, {
 120                 .mask   = PTE_ATTRINDX_MASK,
 121                 .val    = PTE_ATTRINDX(MT_DEVICE_nGnRnE),
 122                 .set    = "DEVICE/nGnRnE",
 123         }, {
 124                 .mask   = PTE_ATTRINDX_MASK,
 125                 .val    = PTE_ATTRINDX(MT_DEVICE_nGnRE),
 126                 .set    = "DEVICE/nGnRE",
 127         }, {
 128                 .mask   = PTE_ATTRINDX_MASK,
 129                 .val    = PTE_ATTRINDX(MT_DEVICE_GRE),
 130                 .set    = "DEVICE/GRE",
 131         }, {
 132                 .mask   = PTE_ATTRINDX_MASK,
 133                 .val    = PTE_ATTRINDX(MT_NORMAL_NC),
 134                 .set    = "MEM/NORMAL-NC",
 135         }, {
 136                 .mask   = PTE_ATTRINDX_MASK,
 137                 .val    = PTE_ATTRINDX(MT_NORMAL),
 138                 .set    = "MEM/NORMAL",
 139         }
 140 };
 141
 142 struct pg_level {
 143         const struct prot_bits *bits;
 144         size_t num;
 145         u64 mask;
 146 };
 147
 148 static struct pg_level pg_level[] = {
 149         {
 150         }, { /* pgd */
 151                 .bits   = pte_bits,
 152                 .num    = ARRAY_SIZE(pte_bits),
 153         }, { /* pud */
 154                 .bits   = pte_bits,
 155                 .num    = ARRAY_SIZE(pte_bits),
 156         }, { /* pmd */
 157                 .bits   = pte_bits,
 158                 .num    = ARRAY_SIZE(pte_bits),
 159         }, { /* pte */
 160                 .bits   = pte_bits,
 161                 .num    = ARRAY_SIZE(pte_bits),
 162         },
 163 };
 164
 165 static void dump_prot(struct pg_state *st, const struct prot_bits *bits,
 166                         size_t num)
 167 {
 168         unsigned i;
 169
 170         for (i = 0; i < num; i++, bits++) {
 171                 const char *s;
 172
 173                 if ((st->current_prot & bits->mask) == bits->val)
 174                         s = bits->set;
 175                 else
 176                         s = bits->clear;
 177
 178                 if (s)
 179                         seq_printf(st->seq, " %s", s);
 180         }
 181 }
 182
 183 static void note_page(struct pg_state *st, unsigned long addr, unsigned level,
 184                                 u64 val)
 185 {
 186         static const char units[] = "KMGTPE";
 187         u64 prot = val & pg_level[level].mask;
 188
 189         if (!st->level) {
 190                 st->level = level;
 191                 st->current_prot = prot;
 192                 st->start_address = addr;
 193                 seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
 194         } else if (prot != st->current_prot || level != st->level ||
 195                    addr >= st->marker[1].start_address) {
 196                 const char *unit = units;
 197                 unsigned long delta;
 198
 199                 if (st->current_prot) {
 200                         seq_printf(st->seq, "0x%16lx-0x%16lx   ",
 201                                    st->start_address, addr);
 202
 203                         delta = (addr - st->start_address) >> 10;
 204                         while (!(delta & 1023) && unit[1]) {
 205                                 delta >>= 10;
 206                                 unit++;
 207                         }
 208                         seq_printf(st->seq, "%9lu%c", delta, *unit);
 209                         if (pg_level[st->level].bits)
 210                                 dump_prot(st, pg_level[st->level].bits,
 211                                           pg_level[st->level].num);
 212                         seq_puts(st->seq, "\n");
 213                 }
 214
 215                 if (addr >= st->marker[1].start_address) {
 216                         st->marker++;
 217                         seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
 218                 }
 219
 220                 st->start_address = addr;
 221                 st->current_prot = prot;
 222                 st->level = level;
 223         }
 224
 225         if (addr >= st->marker[1].start_address) {
 226                 st->marker++;
 227                 seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
 228         }
 229
 230 }
 231
 232 static void walk_pte(struct pg_state *st, pmd_t *pmd, unsigned long start)
 233 {
 234         pte_t *pte = pte_offset_kernel(pmd, 0);
 235         unsigned long addr;
 236         unsigned i;
 237
 238         for (i = 0; i < PTRS_PER_PTE; i++, pte++) {
 239                 addr = start + i * PAGE_SIZE;
 240                 note_page(st, addr, 4, pte_val(*pte));
 241         }
 242 }
 243
 244 static void walk_pmd(struct pg_state *st, pud_t *pud, unsigned long start)
 245 {
 246         pmd_t *pmd = pmd_offset(pud, 0);
 247         unsigned long addr;
 248         unsigned i;
 249
 250         for (i = 0; i < PTRS_PER_PMD; i++, pmd++) {
 251                 addr = start + i * PMD_SIZE;
 252                 if (pmd_none(*pmd) || pmd_sect(*pmd) || pmd_bad(*pmd))
 253                         note_page(st, addr, 3, pmd_val(*pmd));
 254                 else
 255                         walk_pte(st, pmd, addr);
 256         }
 257 }
 258
 259 static void walk_pud(struct pg_state *st, pgd_t *pgd, unsigned long start)
 260 {
 261         pud_t *pud = pud_offset(pgd, 0);
 262         unsigned long addr;
 263         unsigned i;
 264
 265         for (i = 0; i < PTRS_PER_PUD; i++, pud++) {
 266                 addr = start + i * PUD_SIZE;
 267                 if (pud_none(*pud) || pud_sect(*pud) || pud_bad(*pud))
 268                         note_page(st, addr, 2, pud_val(*pud));
 269                 else
 270                         walk_pmd(st, pud, addr);
 271         }
 272 }
 273
 274 static void walk_pgd(struct pg_state *st, struct mm_struct *mm, unsigned long start)
 275 {
 276         pgd_t *pgd = pgd_offset(mm, 0UL);
 277         unsigned i;
 278         unsigned long addr;
 279
 280         for (i = 0; i < PTRS_PER_PGD; i++, pgd++) {
 281                 addr = start + i * PGDIR_SIZE;
 282                 if (pgd_none(*pgd) || pgd_bad(*pgd))
 283                         note_page(st, addr, 1, pgd_val(*pgd));
 284                 else
 285                         walk_pud(st, pgd, addr);
 286         }
 287 }
 288
 289 static int ptdump_show(struct seq_file *m, void *v)
 290 {
 291         struct pg_state st = {
 292                 .seq = m,
 293                 .marker = address_markers,
 294         };
 295
 296         walk_pgd(&st, &init_mm, LOWEST_ADDR);
 297
 298         note_page(&st, 0, 0, 0);
 299         return 0;
 300 }
 301
 302 static int ptdump_open(struct inode *inode, struct file *file)
 303 {
 304         return single_open(file, ptdump_show, NULL);
 305 }
 306
 307 static const struct file_operations ptdump_fops = {
 308         .open           = ptdump_open,
 309         .read           = seq_read,
 310         .llseek         = seq_lseek,
 311         .release        = single_release,
 312 };
 313
 314 static int ptdump_init(void)
 315 {
 316         struct dentry *pe;
 317         unsigned i, j;
 318
 319         for (i = 0; i < ARRAY_SIZE(pg_level); i++)
 320                 if (pg_level[i].bits)
 321                         for (j = 0; j < pg_level[i].num; j++)
 322                                 pg_level[i].mask |= pg_level[i].bits[j].mask;
 323
 324         address_markers[VMEMMAP_START_NR].start_address =
 325                                 (unsigned long)virt_to_page(PAGE_OFFSET);
 326         address_markers[VMEMMAP_END_NR].start_address =
 327                                 (unsigned long)virt_to_page(high_memory);
 328
 329         pe = debugfs_create_file("kernel_page_tables", 0400, NULL, NULL,
 330                                  &ptdump_fops);
 331         return pe ? 0 : -ENOMEM;
 332 }
 333 device_initcall(ptdump_init);