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