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/fs.h>
  18 #include <linux/io.h>
  19 #include <linux/mm.h>
  20 #include <linux/sched.h>
  21 #include <linux/seq_file.h>
  22
  23 #include <asm/fixmap.h>
  24 #include <asm/pgtable.h>
  25
  26 #define LOWEST_ADDR     (UL(0xffffffffffffffff) << VA_BITS)
  27
  28 struct addr_marker {
  29         unsigned long start_address;
  30         const char *name;
  31 };
  32
  33 enum address_markers_idx {
  34         VMALLOC_START_NR = 0,
  35         VMALLOC_END_NR,
  36 #ifdef CONFIG_SPARSEMEM_VMEMMAP
  37         VMEMMAP_START_NR,
  38         VMEMMAP_END_NR,
  39 #endif
  40         PCI_START_NR,
  41         PCI_END_NR,
  42         FIXADDR_START_NR,
  43         FIXADDR_END_NR,
  44         MODULES_START_NR,
  45         MODUELS_END_NR,
  46         KERNEL_SPACE_NR,
  47 };
  48
  49 static struct addr_marker address_markers[] = {
  50         { VMALLOC_START,        "vmalloc() Area" },
  51         { VMALLOC_END,          "vmalloc() End" },
  52 #ifdef CONFIG_SPARSEMEM_VMEMMAP
  53         { 0,                    "vmemmap start" },
  54         { 0,                    "vmemmap end" },
  55 #endif
  56         { (unsigned long) PCI_IOBASE,           "PCI I/O start" },
  57         { (unsigned long) PCI_IOBASE + SZ_16M,  "PCI I/O end" },
  58         { FIXADDR_START,        "Fixmap start" },
  59         { FIXADDR_TOP,          "Fixmap end" },
  60         { MODULES_VADDR,        "Modules start" },
  61         { MODULES_END,          "Modules end" },
  62         { PAGE_OFFSET,          "Kernel Mapping" },
  63         { -1,                   NULL },
  64 };
  65
  66 struct pg_state {
  67         struct seq_file *seq;
  68         const struct addr_marker *marker;
  69         unsigned long start_address;
  70         unsigned level;
  71         u64 current_prot;
  72 };
  73
  74 struct prot_bits {
  75         u64             mask;
  76         u64             val;
  77         const char      *set;
  78         const char      *clear;
  79 };
  80
  81 static const struct prot_bits pte_bits[] = {
  82         {
  83                 .mask   = PTE_USER,
  84                 .val    = PTE_USER,
  85                 .set    = "USR",
  86                 .clear  = "   ",
  87         }, {
  88                 .mask   = PTE_RDONLY,
  89                 .val    = PTE_RDONLY,
  90                 .set    = "ro",
  91                 .clear  = "RW",
  92         }, {
  93                 .mask   = PTE_PXN,
  94                 .val    = PTE_PXN,
  95                 .set    = "NX",
  96                 .clear  = "x ",
  97         }, {
  98                 .mask   = PTE_SHARED,
  99                 .val    = PTE_SHARED,
 100                 .set    = "SHD",
 101                 .clear  = "   ",
 102         }, {
 103                 .mask   = PTE_AF,
 104                 .val    = PTE_AF,
 105                 .set    = "AF",
 106                 .clear  = "  ",
 107         }, {
 108                 .mask   = PTE_NG,
 109                 .val    = PTE_NG,
 110                 .set    = "NG",
 111                 .clear  = "  ",
 112         }, {
 113                 .mask   = PTE_UXN,
 114                 .val    = PTE_UXN,
 115                 .set    = "UXN",
 116         }, {
 117                 .mask   = PTE_ATTRINDX_MASK,
 118                 .val    = PTE_ATTRINDX(MT_DEVICE_nGnRnE),
 119                 .set    = "DEVICE/nGnRnE",
 120         }, {
 121                 .mask   = PTE_ATTRINDX_MASK,
 122                 .val    = PTE_ATTRINDX(MT_DEVICE_nGnRE),
 123                 .set    = "DEVICE/nGnRE",
 124         }, {
 125                 .mask   = PTE_ATTRINDX_MASK,
 126                 .val    = PTE_ATTRINDX(MT_DEVICE_GRE),
 127                 .set    = "DEVICE/GRE",
 128         }, {
 129                 .mask   = PTE_ATTRINDX_MASK,
 130                 .val    = PTE_ATTRINDX(MT_NORMAL_NC),
 131                 .set    = "MEM/NORMAL-NC",
 132         }, {
 133                 .mask   = PTE_ATTRINDX_MASK,
 134                 .val    = PTE_ATTRINDX(MT_NORMAL),
 135                 .set    = "MEM/NORMAL",
 136         }
 137 };
 138
 139 struct pg_level {
 140         const struct prot_bits *bits;
 141         size_t num;
 142         u64 mask;
 143 };
 144
 145 static struct pg_level pg_level[] = {
 146         {
 147         }, { /* pgd */
 148                 .bits   = pte_bits,
 149                 .num    = ARRAY_SIZE(pte_bits),
 150         }, { /* pud */
 151                 .bits   = pte_bits,
 152                 .num    = ARRAY_SIZE(pte_bits),
 153         }, { /* pmd */
 154                 .bits   = pte_bits,
 155                 .num    = ARRAY_SIZE(pte_bits),
 156         }, { /* pte */
 157                 .bits   = pte_bits,
 158                 .num    = ARRAY_SIZE(pte_bits),
 159         },
 160 };
 161
 162 static void dump_prot(struct pg_state *st, const struct prot_bits *bits,
 163                         size_t num)
 164 {
 165         unsigned i;
 166
 167         for (i = 0; i < num; i++, bits++) {
 168                 const char *s;
 169
 170                 if ((st->current_prot & bits->mask) == bits->val)
 171                         s = bits->set;
 172                 else
 173                         s = bits->clear;
 174
 175                 if (s)
 176                         seq_printf(st->seq, " %s", s);
 177         }
 178 }
 179
 180 static void note_page(struct pg_state *st, unsigned long addr, unsigned level,
 181                                 u64 val)
 182 {
 183         static const char units[] = "KMGTPE";
 184         u64 prot = val & pg_level[level].mask;
 185
 186         if (!st->level) {
 187                 st->level = level;
 188                 st->current_prot = prot;
 189                 st->start_address = addr;
 190                 seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
 191         } else if (prot != st->current_prot || level != st->level ||
 192                    addr >= st->marker[1].start_address) {
 193                 const char *unit = units;
 194                 unsigned long delta;
 195
 196                 if (st->current_prot) {
 197                         seq_printf(st->seq, "0x%16lx-0x%16lx   ",
 198                                    st->start_address, addr);
 199
 200                         delta = (addr - st->start_address) >> 10;
 201                         while (!(delta & 1023) && unit[1]) {
 202                                 delta >>= 10;
 203                                 unit++;
 204                         }
 205                         seq_printf(st->seq, "%9lu%c", delta, *unit);
 206                         if (pg_level[st->level].bits)
 207                                 dump_prot(st, pg_level[st->level].bits,
 208                                           pg_level[st->level].num);
 209                         seq_puts(st->seq, "\n");
 210                 }
 211
 212                 if (addr >= st->marker[1].start_address) {
 213                         st->marker++;
 214                         seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
 215                 }
 216
 217                 st->start_address = addr;
 218                 st->current_prot = prot;
 219                 st->level = level;
 220         }
 221
 222         if (addr >= st->marker[1].start_address) {
 223                 st->marker++;
 224                 seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
 225         }
 226
 227 }
 228
 229 static void walk_pte(struct pg_state *st, pmd_t *pmd, unsigned long start)
 230 {
 231         pte_t *pte = pte_offset_kernel(pmd, 0);
 232         unsigned long addr;
 233         unsigned i;
 234
 235         for (i = 0; i < PTRS_PER_PTE; i++, pte++) {
 236                 addr = start + i * PAGE_SIZE;
 237                 note_page(st, addr, 4, pte_val(*pte));
 238         }
 239 }
 240
 241 static void walk_pmd(struct pg_state *st, pud_t *pud, unsigned long start)
 242 {
 243         pmd_t *pmd = pmd_offset(pud, 0);
 244         unsigned long addr;
 245         unsigned i;
 246
 247         for (i = 0; i < PTRS_PER_PMD; i++, pmd++) {
 248                 addr = start + i * PMD_SIZE;
 249                 if (pmd_none(*pmd) || pmd_sect(*pmd) || pmd_bad(*pmd))
 250                         note_page(st, addr, 3, pmd_val(*pmd));
 251                 else
 252                         walk_pte(st, pmd, addr);
 253         }
 254 }
 255
 256 static void walk_pud(struct pg_state *st, pgd_t *pgd, unsigned long start)
 257 {
 258         pud_t *pud = pud_offset(pgd, 0);
 259         unsigned long addr;
 260         unsigned i;
 261
 262         for (i = 0; i < PTRS_PER_PUD; i++, pud++) {
 263                 addr = start + i * PUD_SIZE;
 264                 if (pud_none(*pud) || pud_sect(*pud) || pud_bad(*pud))
 265                         note_page(st, addr, 2, pud_val(*pud));
 266                 else
 267                         walk_pmd(st, pud, addr);
 268         }
 269 }
 270
 271 static void walk_pgd(struct pg_state *st, struct mm_struct *mm, unsigned long start)
 272 {
 273         pgd_t *pgd = pgd_offset(mm, 0UL);
 274         unsigned i;
 275         unsigned long addr;
 276
 277         for (i = 0; i < PTRS_PER_PGD; i++, pgd++) {
 278                 addr = start + i * PGDIR_SIZE;
 279                 if (pgd_none(*pgd) || pgd_bad(*pgd))
 280                         note_page(st, addr, 1, pgd_val(*pgd));
 281                 else
 282                         walk_pud(st, pgd, addr);
 283         }
 284 }
 285
 286 static int ptdump_show(struct seq_file *m, void *v)
 287 {
 288         struct pg_state st = {
 289                 .seq = m,
 290                 .marker = address_markers,
 291         };
 292
 293         walk_pgd(&st, &init_mm, LOWEST_ADDR);
 294
 295         note_page(&st, 0, 0, 0);
 296         return 0;
 297 }
 298
 299 static int ptdump_open(struct inode *inode, struct file *file)
 300 {
 301         return single_open(file, ptdump_show, NULL);
 302 }
 303
 304 static const struct file_operations ptdump_fops = {
 305         .open           = ptdump_open,
 306         .read           = seq_read,
 307         .llseek         = seq_lseek,
 308         .release        = single_release,
 309 };
 310
 311 static int ptdump_init(void)
 312 {
 313         struct dentry *pe;
 314         unsigned i, j;
 315
 316         for (i = 0; i < ARRAY_SIZE(pg_level); i++)
 317                 if (pg_level[i].bits)
 318                         for (j = 0; j < pg_level[i].num; j++)
 319                                 pg_level[i].mask |= pg_level[i].bits[j].mask;
 320
 321         address_markers[VMEMMAP_START_NR].start_address =
 322                                 (unsigned long)virt_to_page(PAGE_OFFSET);
 323         address_markers[VMEMMAP_END_NR].start_address =
 324                                 (unsigned long)virt_to_page(high_memory);
 325
 326         pe = debugfs_create_file("kernel_page_tables", 0400, NULL, NULL,
 327                                  &ptdump_fops);
 328         return pe ? 0 : -ENOMEM;
 329 }
 330 device_initcall(ptdump_init);