/*
* Debug helper to dump the current kernel pagetables of the system
* so that we can see what the various memory ranges are set to.
*
* Derived from x86 implementation:
* (C) Copyright 2008 Intel Corporation
*
* Author: Arjan van de Ven <arjan@linux.intel.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; version 2
* of the License.
*/
#include <linux/debugfs.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/seq_file.h>
#include <asm/fixmap.h>
#include <asm/pgtable.h>
struct addr_marker {
unsigned long start_address;
const char *name;
};
static struct addr_marker address_markers[] = {
{ MODULES_VADDR, "Modules" },
{ PAGE_OFFSET, "Kernel Mapping" },
{ 0, "vmalloc() Area" },
{ VMALLOC_END, "vmalloc() End" },
{ FIXADDR_START, "Fixmap Area" },
{ CONFIG_VECTORS_BASE, "Vectors" },
{ CONFIG_VECTORS_BASE + PAGE_SIZE * 2, "Vectors End" },
{ -1, NULL },
};
struct pg_state {
struct seq_file *seq;
const struct addr_marker *marker;
unsigned long start_address;
unsigned level;
u64 current_prot;
};
struct prot_bits {
u64 mask;
u64 val;
const char *set;
const char *clear;
};
static const struct prot_bits pte_bits[] = {
{
.mask = L_PTE_USER,
.val = L_PTE_USER,
.set = "USR",
.clear = " ",
}, {
.mask = L_PTE_RDONLY,
.val = L_PTE_RDONLY,
.set = "ro",
.clear = "RW",
}, {
.mask = L_PTE_XN,
.val = L_PTE_XN,
.set = "NX",
.clear = "x ",
}, {
.mask = L_PTE_SHARED,
.val = L_PTE_SHARED,
.set = "SHD",
.clear = " ",
}, {
.mask = L_PTE_MT_MASK,
.val = L_PTE_MT_UNCACHED,
.set = "SO/UNCACHED",
}, {
.mask = L_PTE_MT_MASK,
.val = L_PTE_MT_BUFFERABLE,
.set = "MEM/BUFFERABLE/WC",
}, {
.mask = L_PTE_MT_MASK,
.val = L_PTE_MT_WRITETHROUGH,
.set = "MEM/CACHED/WT",
}, {
.mask = L_PTE_MT_MASK,
.val = L_PTE_MT_WRITEBACK,
.set = "MEM/CACHED/WBRA",
#ifndef CONFIG_ARM_LPAE
}, {
.mask = L_PTE_MT_MASK,
.val = L_PTE_MT_MINICACHE,
.set = "MEM/MINICACHE",
#endif
}, {
.mask = L_PTE_MT_MASK,
.val = L_PTE_MT_WRITEALLOC,
.set = "MEM/CACHED/WBWA",
}, {
.mask = L_PTE_MT_MASK,
.val = L_PTE_MT_DEV_SHARED,
.set = "DEV/SHARED",
#ifndef CONFIG_ARM_LPAE
}, {
.mask = L_PTE_MT_MASK,
.val = L_PTE_MT_DEV_NONSHARED,
.set = "DEV/NONSHARED",
#endif
}, {
.mask = L_PTE_MT_MASK,
.val = L_PTE_MT_DEV_WC,
.set = "DEV/WC",
}, {
.mask = L_PTE_MT_MASK,
.val = L_PTE_MT_DEV_CACHED,
.set = "DEV/CACHED",
},
};
static const struct prot_bits section_bits[] = {
#ifdef CONFIG_ARM_LPAE
{
.mask = PMD_SECT_USER,
.val = PMD_SECT_USER,
.set = "USR",
}, {
.mask = L_PMD_SECT_RDONLY,
.val = L_PMD_SECT_RDONLY,
.set = "ro",
.clear = "RW",
#elif __LINUX_ARM_ARCH__ >= 6
{
.mask = PMD_SECT_APX | PMD_SECT_AP_READ | PMD_SECT_AP_WRITE,
.val = PMD_SECT_APX | PMD_SECT_AP_WRITE,
.set = " ro",
}, {
.mask = PMD_SECT_APX | PMD_SECT_AP_READ | PMD_SECT_AP_WRITE,
.val = PMD_SECT_AP_WRITE,
.set = " RW",
}, {
.mask = PMD_SECT_APX | PMD_SECT_AP_READ | PMD_SECT_AP_WRITE,
.val = PMD_SECT_AP_READ,
.set = "USR ro",
}, {
.mask = PMD_SECT_APX | PMD_SECT_AP_READ | PMD_SECT_AP_WRITE,
.val = PMD_SECT_AP_READ | PMD_SECT_AP_WRITE,
.set = "USR RW",
#else /* ARMv4/ARMv5 */
/* These are approximate */
{
.mask = PMD_SECT_AP_READ | PMD_SECT_AP_WRITE,
.val = 0,
.set = " ro",
}, {
.mask = PMD_SECT_AP_READ | PMD_SECT_AP_WRITE,
.val = PMD_SECT_AP_WRITE,
.set = " RW",
}, {
.mask = PMD_SECT_AP_READ | PMD_SECT_AP_WRITE,
.val = PMD_SECT_AP_READ,
.set = "USR ro",
}, {
.mask = PMD_SECT_AP_READ | PMD_SECT_AP_WRITE,
.val = PMD_SECT_AP_READ | PMD_SECT_AP_WRITE,
.set = "USR RW",
#endif
}, {
.mask = PMD_SECT_XN,
.val = PMD_SECT_XN,
.set = "NX",
.clear = "x ",
}, {
.mask = PMD_SECT_S,
.val = PMD_SECT_S,
.set = "SHD",
.clear = " ",
},
};
struct pg_level {
const struct prot_bits *bits;
size_t num;
u64 mask;
};
static struct pg_level pg_level[] = {
{
}, { /* pgd */
}, { /* pud */
}, { /* pmd */
.bits = section_bits,
.num = ARRAY_SIZE(section_bits),
}, { /* pte */
.bits = pte_bits,
.num = ARRAY_SIZE(pte_bits),
},
};
static void dump_prot(struct pg_state *st, const struct prot_bits *bits, size_t num)
{
unsigned i;
for (i = 0; i < num; i++, bits++) {
const char *s;
if ((st->current_prot & bits->mask) == bits->val)
s = bits->set;
else
s = bits->clear;
if (s)
seq_printf(st->seq, " %s", s);
}
}
static void note_page(struct pg_state *st, unsigned long addr, unsigned level, u64 val)
{
static const char units[] = "KMGTPE";
u64 prot = val & pg_level[level].mask;
if (addr < USER_PGTABLES_CEILING)
return;
if (!st->level) {
st->level = level;
st->current_prot = prot;
seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
} else if (prot != st->current_prot || level != st->level ||
addr >= st->marker[1].start_address) {
const char *unit = units;
unsigned long delta;
if (st->current_prot) {
seq_printf(st->seq, "0x%08lx-0x%08lx ",
st->start_address, addr);
delta = (addr - st->start_address) >> 10;
while (!(delta & 1023) && unit[1]) {
delta >>= 10;
unit++;
}
seq_printf(st->seq, "%9lu%c", delta, *unit);
if (pg_level[st->level].bits)
dump_prot(st, pg_level[st->level].bits, pg_level[st->level].num);
seq_printf(st->seq, "\n");
}
if (addr >= st->marker[1].start_address) {
st->marker++;
seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
}
st->start_address = addr;
st->current_prot = prot;
st->level = level;
}
}
static void walk_pte(struct pg_state *st, pmd_t *pmd, unsigned long start)
{
pte_t *pte = pte_offset_kernel(pmd, 0);
unsigned long addr;
unsigned i;
for (i = 0; i < PTRS_PER_PTE; i++, pte++) {
addr = start + i * PAGE_SIZE;
note_page(st, addr, 4, pte_val(*pte));
}
}
static void walk_pmd(struct pg_state *st, pud_t *pud, unsigned long start)
{
pmd_t *pmd = pmd_offset(pud, 0);
unsigned long addr;
unsigned i;
for (i = 0; i < PTRS_PER_PMD; i++, pmd++) {
addr = start + i * PMD_SIZE;
if (pmd_none(*pmd) || pmd_large(*pmd) || !pmd_present(*pmd))
note_page(st, addr, 3, pmd_val(*pmd));
else
walk_pte(st, pmd, addr);
if (SECTION_SIZE < PMD_SIZE && pmd_large(pmd[1]))
note_page(st, addr + SECTION_SIZE, 3, pmd_val(pmd[1]));
}
}
static void walk_pud(struct pg_state *st, pgd_t *pgd, unsigned long start)
{
pud_t *pud = pud_offset(pgd, 0);
unsigned long addr;
unsigned i;
for (i = 0; i < PTRS_PER_PUD; i++, pud++) {
addr = start + i * PUD_SIZE;
if (!pud_none(*pud)) {
walk_pmd(st, pud, addr);
} else {
note_page(st, addr, 2, pud_val(*pud));
}
}
}
static void walk_pgd(struct seq_file *m)
{
pgd_t *pgd = swapper_pg_dir;
struct pg_state st;
unsigned long addr;
unsigned i, pgdoff = USER_PGTABLES_CEILING / PGDIR_SIZE;
memset(&st, 0, sizeof(st));
st.seq = m;
st.marker = address_markers;
pgd += pgdoff;
for (i = pgdoff; i < PTRS_PER_PGD; i++, pgd++) {
addr = i * PGDIR_SIZE;
if (!pgd_none(*pgd)) {
walk_pud(&st, pgd, addr);
} else {
note_page(&st, addr, 1, pgd_val(*pgd));
}
}
note_page(&st, 0, 0, 0);
}
static int ptdump_show(struct seq_file *m, void *v)
{
walk_pgd(m);
return 0;
}
static int ptdump_open(struct inode *inode, struct file *file)
{
return single_open(file, ptdump_show, NULL);
}
static const struct file_operations ptdump_fops = {
.open = ptdump_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
static int ptdump_init(void)
{
struct dentry *pe;
unsigned i, j;
for (i = 0; i < ARRAY_SIZE(pg_level); i++)
if (pg_level[i].bits)
for (j = 0; j < pg_level[i].num; j++)
pg_level[i].mask |= pg_level[i].bits[j].mask;
address_markers[2].start_address = VMALLOC_START;
pe = debugfs_create_file("kernel_page_tables", 0400, NULL, NULL,
&ptdump_fops);
return pe ? 0 : -ENOMEM;
}
__initcall(ptdump_init);
