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
);