1 // SPDX-License-Identifier: GPL-2.0-only
3 * Copyright (c) 2014, The Linux Foundation. All rights reserved.
4 * Debug helper to dump the current kernel pagetables of the system
5 * so that we can see what the various memory ranges are set to.
7 * Derived from x86 and arm implementation:
8 * (C) Copyright 2008 Intel Corporation
10 * Author: Arjan van de Ven <arjan@linux.intel.com>
12 #include <linux/debugfs.h>
13 #include <linux/errno.h>
16 #include <linux/init.h>
18 #include <linux/ptdump.h>
19 #include <linux/sched.h>
20 #include <linux/seq_file.h>
22 #include <asm/fixmap.h>
23 #include <asm/kasan.h>
24 #include <asm/memory.h>
25 #include <asm/pgtable-hwdef.h>
26 #include <asm/ptdump.h>
29 enum address_markers_idx {
32 #if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
37 static struct addr_marker address_markers[] = {
38 { PAGE_OFFSET, "Linear Mapping start" },
39 { 0 /* PAGE_END */, "Linear Mapping end" },
40 #if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
41 { 0 /* KASAN_SHADOW_START */, "Kasan shadow start" },
42 { KASAN_SHADOW_END, "Kasan shadow end" },
44 { MODULES_VADDR, "Modules start" },
45 { MODULES_END, "Modules end" },
46 { VMALLOC_START, "vmalloc() area" },
47 { VMALLOC_END, "vmalloc() end" },
48 { FIXADDR_TOT_START, "Fixmap start" },
49 { FIXADDR_TOP, "Fixmap end" },
50 { PCI_IO_START, "PCI I/O start" },
51 { PCI_IO_END, "PCI I/O end" },
52 { VMEMMAP_START, "vmemmap start" },
53 { VMEMMAP_START + VMEMMAP_SIZE, "vmemmap end" },
57 #define pt_dump_seq_printf(m, fmt, args...) \
60 seq_printf(m, fmt, ##args); \
63 #define pt_dump_seq_puts(m, fmt) \
70 * The page dumper groups page table entries of the same type into a single
71 * description. It uses pg_state to track the range information while
72 * iterating over the pte entries. When the continuity is broken it then
73 * dumps out a description of the range.
76 struct ptdump_state ptdump;
78 const struct addr_marker *marker;
79 unsigned long start_address;
83 unsigned long wx_pages;
84 unsigned long uxn_pages;
94 static const struct prot_bits pte_bits[] = {
136 .mask = PTE_TABLE_BIT,
137 .val = PTE_TABLE_BIT,
151 .mask = PTE_ATTRINDX_MASK,
152 .val = PTE_ATTRINDX(MT_DEVICE_nGnRnE),
153 .set = "DEVICE/nGnRnE",
155 .mask = PTE_ATTRINDX_MASK,
156 .val = PTE_ATTRINDX(MT_DEVICE_nGnRE),
157 .set = "DEVICE/nGnRE",
159 .mask = PTE_ATTRINDX_MASK,
160 .val = PTE_ATTRINDX(MT_NORMAL_NC),
161 .set = "MEM/NORMAL-NC",
163 .mask = PTE_ATTRINDX_MASK,
164 .val = PTE_ATTRINDX(MT_NORMAL),
167 .mask = PTE_ATTRINDX_MASK,
168 .val = PTE_ATTRINDX(MT_NORMAL_TAGGED),
169 .set = "MEM/NORMAL-TAGGED",
174 const struct prot_bits *bits;
180 static struct pg_level pg_level[] = {
184 .num = ARRAY_SIZE(pte_bits),
188 .num = ARRAY_SIZE(pte_bits),
190 .name = (CONFIG_PGTABLE_LEVELS > 3) ? "PUD" : "PGD",
192 .num = ARRAY_SIZE(pte_bits),
194 .name = (CONFIG_PGTABLE_LEVELS > 2) ? "PMD" : "PGD",
196 .num = ARRAY_SIZE(pte_bits),
200 .num = ARRAY_SIZE(pte_bits),
204 static void dump_prot(struct pg_state *st, const struct prot_bits *bits,
209 for (i = 0; i < num; i++, bits++) {
212 if ((st->current_prot & bits->mask) == bits->val)
218 pt_dump_seq_printf(st->seq, " %s", s);
222 static void note_prot_uxn(struct pg_state *st, unsigned long addr)
227 if ((st->current_prot & PTE_UXN) == PTE_UXN)
230 WARN_ONCE(1, "arm64/mm: Found non-UXN mapping at address %p/%pS\n",
231 (void *)st->start_address, (void *)st->start_address);
233 st->uxn_pages += (addr - st->start_address) / PAGE_SIZE;
236 static void note_prot_wx(struct pg_state *st, unsigned long addr)
240 if ((st->current_prot & PTE_RDONLY) == PTE_RDONLY)
242 if ((st->current_prot & PTE_PXN) == PTE_PXN)
245 WARN_ONCE(1, "arm64/mm: Found insecure W+X mapping at address %p/%pS\n",
246 (void *)st->start_address, (void *)st->start_address);
248 st->wx_pages += (addr - st->start_address) / PAGE_SIZE;
251 static void note_page(struct ptdump_state *pt_st, unsigned long addr, int level,
254 struct pg_state *st = container_of(pt_st, struct pg_state, ptdump);
255 static const char units[] = "KMGTPE";
259 prot = val & pg_level[level].mask;
261 if (st->level == -1) {
263 st->current_prot = prot;
264 st->start_address = addr;
265 pt_dump_seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
266 } else if (prot != st->current_prot || level != st->level ||
267 addr >= st->marker[1].start_address) {
268 const char *unit = units;
271 if (st->current_prot) {
272 note_prot_uxn(st, addr);
273 note_prot_wx(st, addr);
276 pt_dump_seq_printf(st->seq, "0x%016lx-0x%016lx ",
277 st->start_address, addr);
279 delta = (addr - st->start_address) >> 10;
280 while (!(delta & 1023) && unit[1]) {
284 pt_dump_seq_printf(st->seq, "%9lu%c %s", delta, *unit,
285 pg_level[st->level].name);
286 if (st->current_prot && pg_level[st->level].bits)
287 dump_prot(st, pg_level[st->level].bits,
288 pg_level[st->level].num);
289 pt_dump_seq_puts(st->seq, "\n");
291 if (addr >= st->marker[1].start_address) {
293 pt_dump_seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
296 st->start_address = addr;
297 st->current_prot = prot;
301 if (addr >= st->marker[1].start_address) {
303 pt_dump_seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
308 void ptdump_walk(struct seq_file *s, struct ptdump_info *info)
310 unsigned long end = ~0UL;
313 if (info->base_addr < TASK_SIZE_64)
316 st = (struct pg_state){
318 .marker = info->markers,
321 .note_page = note_page,
322 .range = (struct ptdump_range[]){
323 {info->base_addr, end},
329 ptdump_walk_pgd(&st.ptdump, info->mm, NULL);
332 static void __init ptdump_initialize(void)
336 for (i = 0; i < ARRAY_SIZE(pg_level); i++)
337 if (pg_level[i].bits)
338 for (j = 0; j < pg_level[i].num; j++)
339 pg_level[i].mask |= pg_level[i].bits[j].mask;
342 static struct ptdump_info kernel_ptdump_info = {
344 .markers = address_markers,
345 .base_addr = PAGE_OFFSET,
348 void ptdump_check_wx(void)
350 struct pg_state st = {
352 .marker = (struct addr_marker[]) {
359 .note_page = note_page,
360 .range = (struct ptdump_range[]) {
367 ptdump_walk_pgd(&st.ptdump, &init_mm, NULL);
369 if (st.wx_pages || st.uxn_pages)
370 pr_warn("Checked W+X mappings: FAILED, %lu W+X pages found, %lu non-UXN pages found\n",
371 st.wx_pages, st.uxn_pages);
373 pr_info("Checked W+X mappings: passed, no W+X pages found\n");
376 static int __init ptdump_init(void)
378 address_markers[PAGE_END_NR].start_address = PAGE_END;
379 #if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
380 address_markers[KASAN_START_NR].start_address = KASAN_SHADOW_START;
383 ptdump_debugfs_register(&kernel_ptdump_info, "kernel_page_tables");
386 device_initcall(ptdump_init);