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.
6 * Derived from x86 and arm implementation:
7 * (C) Copyright 2008 Intel Corporation
9 * Author: Arjan van de Ven <arjan@linux.intel.com>
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
16 #include <linux/debugfs.h>
19 #include <linux/sched.h>
20 #include <linux/seq_file.h>
22 #include <asm/fixmap.h>
23 #include <asm/pgtable.h>
25 #define LOWEST_ADDR (UL(0xffffffffffffffff) << VA_BITS)
28 unsigned long start_address;
32 enum address_markers_idx {
35 #ifdef CONFIG_SPARSEMEM_VMEMMAP
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" },
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" },
67 const struct addr_marker *marker;
68 unsigned long start_address;
80 static const struct prot_bits pte_bits[] = {
116 .mask = PTE_ATTRINDX_MASK,
117 .val = PTE_ATTRINDX(MT_DEVICE_nGnRnE),
118 .set = "DEVICE/nGnRnE",
120 .mask = PTE_ATTRINDX_MASK,
121 .val = PTE_ATTRINDX(MT_DEVICE_nGnRE),
122 .set = "DEVICE/nGnRE",
124 .mask = PTE_ATTRINDX_MASK,
125 .val = PTE_ATTRINDX(MT_DEVICE_GRE),
128 .mask = PTE_ATTRINDX_MASK,
129 .val = PTE_ATTRINDX(MT_NORMAL_NC),
130 .set = "MEM/NORMAL-NC",
132 .mask = PTE_ATTRINDX_MASK,
133 .val = PTE_ATTRINDX(MT_NORMAL),
139 const struct prot_bits *bits;
144 static struct pg_level pg_level[] = {
148 .num = ARRAY_SIZE(pte_bits),
151 .num = ARRAY_SIZE(pte_bits),
154 .num = ARRAY_SIZE(pte_bits),
157 .num = ARRAY_SIZE(pte_bits),
161 static void dump_prot(struct pg_state *st, const struct prot_bits *bits,
166 for (i = 0; i < num; i++, bits++) {
169 if ((st->current_prot & bits->mask) == bits->val)
175 seq_printf(st->seq, " %s", s);
179 static void note_page(struct pg_state *st, unsigned long addr, unsigned level,
182 static const char units[] = "KMGTPE";
183 u64 prot = val & pg_level[level].mask;
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;
195 if (st->current_prot) {
196 seq_printf(st->seq, "0x%16lx-0x%16lx ",
197 st->start_address, addr);
199 delta = (addr - st->start_address) >> 10;
200 while (!(delta & 1023) && unit[1]) {
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");
211 if (addr >= st->marker[1].start_address) {
213 seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
216 st->start_address = addr;
217 st->current_prot = prot;
221 if (addr >= st->marker[1].start_address) {
223 seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
228 static void walk_pte(struct pg_state *st, pmd_t *pmd, unsigned long start)
230 pte_t *pte = pte_offset_kernel(pmd, 0);
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));
240 static void walk_pmd(struct pg_state *st, pud_t *pud, unsigned long start)
242 pmd_t *pmd = pmd_offset(pud, 0);
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));
251 walk_pte(st, pmd, addr);
255 static void walk_pud(struct pg_state *st, pgd_t *pgd, unsigned long start)
257 pud_t *pud = pud_offset(pgd, 0);
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));
266 walk_pmd(st, pud, addr);
270 static void walk_pgd(struct pg_state *st, struct mm_struct *mm, unsigned long start)
272 pgd_t *pgd = pgd_offset(mm, 0UL);
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));
281 walk_pud(st, pgd, addr);
285 static int ptdump_show(struct seq_file *m, void *v)
287 struct pg_state st = {
289 .marker = address_markers,
292 walk_pgd(&st, &init_mm, LOWEST_ADDR);
294 note_page(&st, 0, 0, 0);
298 static int ptdump_open(struct inode *inode, struct file *file)
300 return single_open(file, ptdump_show, NULL);
303 static const struct file_operations ptdump_fops = {
307 .release = single_release,
310 static int ptdump_init(void)
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;
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);
325 pe = debugfs_create_file("kernel_page_tables", 0400, NULL, NULL,
327 return pe ? 0 : -ENOMEM;
329 device_initcall(ptdump_init);