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         MODUELS_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 struct pg_state {
  71         struct seq_file *seq;
  72         const struct addr_marker *marker;
  73         unsigned long start_address;
  74         unsigned level;
  75         u64 current_prot;
  76 };
  77
  78 struct prot_bits {
  79         u64             mask;
  80         u64             val;
  81         const char      *set;
  82         const char      *clear;
  83 };
  84
  85 static const struct prot_bits pte_bits[] = {
  86         {
  87                 .mask   = PTE_USER,
  88                 .val    = PTE_USER,
  89                 .set    = "USR",
  90                 .clear  = "   ",
  91         }, {
  92                 .mask   = PTE_RDONLY,
  93                 .val    = PTE_RDONLY,
  94                 .set    = "ro",
  95                 .clear  = "RW",
  96         }, {
  97                 .mask   = PTE_PXN,
  98                 .val    = PTE_PXN,
  99                 .set    = "NX",
 100                 .clear  = "x ",
 101         }, {
 102                 .mask   = PTE_SHARED,
 103                 .val    = PTE_SHARED,
 104                 .set    = "SHD",
 105                 .clear  = "   ",
 106         }, {
 107                 .mask   = PTE_AF,
 108                 .val    = PTE_AF,
 109                 .set    = "AF",
 110                 .clear  = "  ",
 111         }, {
 112                 .mask   = PTE_NG,
 113                 .val    = PTE_NG,
 114                 .set    = "NG",
 115                 .clear  = "  ",
 116         }, {
 117                 .mask   = PTE_UXN,
 118                 .val    = PTE_UXN,
 119                 .set    = "UXN",
 120         }, {
 121                 .mask   = PTE_ATTRINDX_MASK,
 122                 .val    = PTE_ATTRINDX(MT_DEVICE_nGnRnE),
 123                 .set    = "DEVICE/nGnRnE",
 124         }, {
 125                 .mask   = PTE_ATTRINDX_MASK,
 126                 .val    = PTE_ATTRINDX(MT_DEVICE_nGnRE),
 127                 .set    = "DEVICE/nGnRE",
 128         }, {
 129                 .mask   = PTE_ATTRINDX_MASK,
 130                 .val    = PTE_ATTRINDX(MT_DEVICE_GRE),
 131                 .set    = "DEVICE/GRE",
 132         }, {
 133                 .mask   = PTE_ATTRINDX_MASK,
 134                 .val    = PTE_ATTRINDX(MT_NORMAL_NC),
 135                 .set    = "MEM/NORMAL-NC",
 136         }, {
 137                 .mask   = PTE_ATTRINDX_MASK,
 138                 .val    = PTE_ATTRINDX(MT_NORMAL),
 139                 .set    = "MEM/NORMAL",
 140         }
 141 };
 142
 143 struct pg_level {
 144         const struct prot_bits *bits;
 145         size_t num;
 146         u64 mask;
 147 };
 148
 149 static struct pg_level pg_level[] = {
 150         {
 151         }, { /* pgd */
 152                 .bits   = pte_bits,
 153                 .num    = ARRAY_SIZE(pte_bits),
 154         }, { /* pud */
 155                 .bits   = pte_bits,
 156                 .num    = ARRAY_SIZE(pte_bits),
 157         }, { /* pmd */
 158                 .bits   = pte_bits,
 159                 .num    = ARRAY_SIZE(pte_bits),
 160         }, { /* pte */
 161                 .bits   = pte_bits,
 162                 .num    = ARRAY_SIZE(pte_bits),
 163         },
 164 };
 165
 166 static void dump_prot(struct pg_state *st, const struct prot_bits *bits,
 167                         size_t num)
 168 {
 169         unsigned i;
 170
 171         for (i = 0; i < num; i++, bits++) {
 172                 const char *s;
 173
 174                 if ((st->current_prot & bits->mask) == bits->val)
 175                         s = bits->set;
 176                 else
 177                         s = bits->clear;
 178
 179                 if (s)
 180                         seq_printf(st->seq, " %s", s);
 181         }
 182 }
 183
 184 static void note_page(struct pg_state *st, unsigned long addr, unsigned level,
 185                                 u64 val)
 186 {
 187         static const char units[] = "KMGTPE";
 188         u64 prot = val & pg_level[level].mask;
 189
 190         if (!st->level) {
 191                 st->level = level;
 192                 st->current_prot = prot;
 193                 st->start_address = addr;
 194                 seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
 195         } else if (prot != st->current_prot || level != st->level ||
 196                    addr >= st->marker[1].start_address) {
 197                 const char *unit = units;
 198                 unsigned long delta;
 199
 200                 if (st->current_prot) {
 201                         seq_printf(st->seq, "0x%16lx-0x%16lx   ",
 202                                    st->start_address, addr);
 203
 204                         delta = (addr - st->start_address) >> 10;
 205                         while (!(delta & 1023) && unit[1]) {
 206                                 delta >>= 10;
 207                                 unit++;
 208                         }
 209                         seq_printf(st->seq, "%9lu%c", delta, *unit);
 210                         if (pg_level[st->level].bits)
 211                                 dump_prot(st, pg_level[st->level].bits,
 212                                           pg_level[st->level].num);
 213                         seq_puts(st->seq, "\n");
 214                 }
 215
 216                 if (addr >= st->marker[1].start_address) {
 217                         st->marker++;
 218                         seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
 219                 }
 220
 221                 st->start_address = addr;
 222                 st->current_prot = prot;
 223                 st->level = level;
 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 }
 232
 233 static void walk_pte(struct pg_state *st, pmd_t *pmd, unsigned long start)
 234 {
 235         pte_t *pte = pte_offset_kernel(pmd, 0);
 236         unsigned long addr;
 237         unsigned i;
 238
 239         for (i = 0; i < PTRS_PER_PTE; i++, pte++) {
 240                 addr = start + i * PAGE_SIZE;
 241                 note_page(st, addr, 4, pte_val(*pte));
 242         }
 243 }
 244
 245 static void walk_pmd(struct pg_state *st, pud_t *pud, unsigned long start)
 246 {
 247         pmd_t *pmd = pmd_offset(pud, 0);
 248         unsigned long addr;
 249         unsigned i;
 250
 251         for (i = 0; i < PTRS_PER_PMD; i++, pmd++) {
 252                 addr = start + i * PMD_SIZE;
 253                 if (pmd_none(*pmd) || pmd_sect(*pmd)) {
 254                         note_page(st, addr, 3, pmd_val(*pmd));
 255                 } else {
 256                         BUG_ON(pmd_bad(*pmd));
 257                         walk_pte(st, pmd, addr);
 258                 }
 259         }
 260 }
 261
 262 static void walk_pud(struct pg_state *st, pgd_t *pgd, unsigned long start)
 263 {
 264         pud_t *pud = pud_offset(pgd, 0);
 265         unsigned long addr;
 266         unsigned i;
 267
 268         for (i = 0; i < PTRS_PER_PUD; i++, pud++) {
 269                 addr = start + i * PUD_SIZE;
 270                 if (pud_none(*pud) || pud_sect(*pud)) {
 271                         note_page(st, addr, 2, pud_val(*pud));
 272                 } else {
 273                         BUG_ON(pud_bad(*pud));
 274                         walk_pmd(st, pud, addr);
 275                 }
 276         }
 277 }
 278
 279 static void walk_pgd(struct pg_state *st, struct mm_struct *mm, unsigned long start)
 280 {
 281         pgd_t *pgd = pgd_offset(mm, 0UL);
 282         unsigned i;
 283         unsigned long addr;
 284
 285         for (i = 0; i < PTRS_PER_PGD; i++, pgd++) {
 286                 addr = start + i * PGDIR_SIZE;
 287                 if (pgd_none(*pgd)) {
 288                         note_page(st, addr, 1, pgd_val(*pgd));
 289                 } else {
 290                         BUG_ON(pgd_bad(*pgd));
 291                         walk_pud(st, pgd, addr);
 292                 }
 293         }
 294 }
 295
 296 static int ptdump_show(struct seq_file *m, void *v)
 297 {
 298         struct pg_state st = {
 299                 .seq = m,
 300                 .marker = address_markers,
 301         };
 302
 303         walk_pgd(&st, &init_mm, LOWEST_ADDR);
 304
 305         note_page(&st, 0, 0, 0);
 306         return 0;
 307 }
 308
 309 static int ptdump_open(struct inode *inode, struct file *file)
 310 {
 311         return single_open(file, ptdump_show, NULL);
 312 }
 313
 314 static const struct file_operations ptdump_fops = {
 315         .open           = ptdump_open,
 316         .read           = seq_read,
 317         .llseek         = seq_lseek,
 318         .release        = single_release,
 319 };
 320
 321 static int ptdump_init(void)
 322 {
 323         struct dentry *pe;
 324         unsigned i, j;
 325
 326         for (i = 0; i < ARRAY_SIZE(pg_level); i++)
 327                 if (pg_level[i].bits)
 328                         for (j = 0; j < pg_level[i].num; j++)
 329                                 pg_level[i].mask |= pg_level[i].bits[j].mask;
 330
 331         address_markers[VMEMMAP_START_NR].start_address =
 332                                 (unsigned long)virt_to_page(PAGE_OFFSET);
 333         address_markers[VMEMMAP_END_NR].start_address =
 334                                 (unsigned long)virt_to_page(high_memory);
 335
 336         pe = debugfs_create_file("kernel_page_tables", 0400, NULL, NULL,
 337                                  &ptdump_fops);
 338         return pe ? 0 : -ENOMEM;
 339 }
 340 device_initcall(ptdump_init);