Release 4.14 arch/x86/mm/dump_pagetables.c
/*
* Debug helper to dump the current kernel pagetables of the system
* so that we can see what the various memory ranges are set to.
*
* (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/kasan.h>
#include <linux/mm.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/seq_file.h>
#include <asm/pgtable.h>
/*
* The dumper groups pagetable entries of the same type into one, and for
* that it needs to keep some state when walking, and flush this state
* when a "break" in the continuity is found.
*/
struct pg_state {
int level;
pgprot_t current_prot;
unsigned long start_address;
unsigned long current_address;
const struct addr_marker *marker;
unsigned long lines;
bool to_dmesg;
bool check_wx;
unsigned long wx_pages;
};
struct addr_marker {
unsigned long start_address;
const char *name;
unsigned long max_lines;
};
/* indices for address_markers; keep sync'd w/ address_markers below */
enum address_markers_idx {
USER_SPACE_NR = 0,
#ifdef CONFIG_X86_64
KERNEL_SPACE_NR,
LOW_KERNEL_NR,
VMALLOC_START_NR,
VMEMMAP_START_NR,
#ifdef CONFIG_KASAN
KASAN_SHADOW_START_NR,
KASAN_SHADOW_END_NR,
#endif
# ifdef CONFIG_X86_ESPFIX64
ESPFIX_START_NR,
# endif
HIGH_KERNEL_NR,
MODULES_VADDR_NR,
MODULES_END_NR,
#else
KERNEL_SPACE_NR,
VMALLOC_START_NR,
VMALLOC_END_NR,
# ifdef CONFIG_HIGHMEM
PKMAP_BASE_NR,
# endif
FIXADDR_START_NR,
#endif
};
/* Address space markers hints */
static struct addr_marker address_markers[] = {
{ 0, "User Space" },
#ifdef CONFIG_X86_64
{ 0x8000000000000000UL, "Kernel Space" },
{ 0/* PAGE_OFFSET */, "Low Kernel Mapping" },
{ 0/* VMALLOC_START */, "vmalloc() Area" },
{ 0/* VMEMMAP_START */, "Vmemmap" },
#ifdef CONFIG_KASAN
{ KASAN_SHADOW_START, "KASAN shadow" },
{ KASAN_SHADOW_END, "KASAN shadow end" },
#endif
# ifdef CONFIG_X86_ESPFIX64
{ ESPFIX_BASE_ADDR, "ESPfix Area", 16 },
# endif
# ifdef CONFIG_EFI
{ EFI_VA_END, "EFI Runtime Services" },
# endif
{ __START_KERNEL_map, "High Kernel Mapping" },
{ MODULES_VADDR, "Modules" },
{ MODULES_END, "End Modules" },
#else
{ PAGE_OFFSET, "Kernel Mapping" },
{ 0/* VMALLOC_START */, "vmalloc() Area" },
{ 0/*VMALLOC_END*/, "vmalloc() End" },
# ifdef CONFIG_HIGHMEM
{ 0/*PKMAP_BASE*/, "Persistent kmap() Area" },
# endif
{ 0/*FIXADDR_START*/, "Fixmap Area" },
#endif
{ -1, NULL } /* End of list */
};
/* Multipliers for offsets within the PTEs */
#define PTE_LEVEL_MULT (PAGE_SIZE)
#define PMD_LEVEL_MULT (PTRS_PER_PTE * PTE_LEVEL_MULT)
#define PUD_LEVEL_MULT (PTRS_PER_PMD * PMD_LEVEL_MULT)
#define P4D_LEVEL_MULT (PTRS_PER_PUD * PUD_LEVEL_MULT)
#define PGD_LEVEL_MULT (PTRS_PER_P4D * P4D_LEVEL_MULT)
#define pt_dump_seq_printf(m, to_dmesg, fmt, args...) \
({ \
if (to_dmesg) \
printk(KERN_INFO fmt, ##args); \
else \
if (m) \
seq_printf(m, fmt, ##args); \
})
#define pt_dump_cont_printf(m, to_dmesg, fmt, args...) \
({ \
if (to_dmesg) \
printk(KERN_CONT fmt, ##args); \
else \
if (m) \
seq_printf(m, fmt, ##args); \
})
/*
* Print a readable form of a pgprot_t to the seq_file
*/
static void printk_prot(struct seq_file *m, pgprot_t prot, int level, bool dmsg)
{
pgprotval_t pr = pgprot_val(prot);
static const char * const level_name[] =
{ "cr3", "pgd", "p4d", "pud", "pmd", "pte" };
if (!pgprot_val(prot)) {
/* Not present */
pt_dump_cont_printf(m, dmsg, " ");
} else {
if (pr & _PAGE_USER)
pt_dump_cont_printf(m, dmsg, "USR ");
else
pt_dump_cont_printf(m, dmsg, " ");
if (pr & _PAGE_RW)
pt_dump_cont_printf(m, dmsg, "RW ");
else
pt_dump_cont_printf(m, dmsg, "ro ");
if (pr & _PAGE_PWT)
pt_dump_cont_printf(m, dmsg, "PWT ");
else
pt_dump_cont_printf(m, dmsg, " ");
if (pr & _PAGE_PCD)
pt_dump_cont_printf(m, dmsg, "PCD ");
else
pt_dump_cont_printf(m, dmsg, " ");
/* Bit 7 has a different meaning on level 3 vs 4 */
if (level <= 4 && pr & _PAGE_PSE)
pt_dump_cont_printf(m, dmsg, "PSE ");
else
pt_dump_cont_printf(m, dmsg, " ");
if ((level == 5 && pr & _PAGE_PAT) ||
((level == 4 || level == 3) && pr & _PAGE_PAT_LARGE))
pt_dump_cont_printf(m, dmsg, "PAT ");
else
pt_dump_cont_printf(m, dmsg, " ");
if (pr & _PAGE_GLOBAL)
pt_dump_cont_printf(m, dmsg, "GLB ");
else
pt_dump_cont_printf(m, dmsg, " ");
if (pr & _PAGE_NX)
pt_dump_cont_printf(m, dmsg, "NX ");
else
pt_dump_cont_printf(m, dmsg, "x ");
}
pt_dump_cont_printf(m, dmsg, "%s\n", level_name[level]);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Arjan van de Ven | 177 | 56.37% | 1 | 16.67% |
| Borislav Petkov | 57 | 18.15% | 1 | 16.67% |
| H. Peter Anvin | 51 | 16.24% | 1 | 16.67% |
| Juergen Gross | 22 | 7.01% | 1 | 16.67% |
| Kirill A. Shutemov | 6 | 1.91% | 1 | 16.67% |
| Toshi Kani | 1 | 0.32% | 1 | 16.67% |
| Total | 314 | 100.00% | 6 | 100.00% |
/*
* On 64 bits, sign-extend the 48 bit address to 64 bit
*/
static unsigned long normalize_addr(unsigned long u)
{
int shift;
if (!IS_ENABLED(CONFIG_X86_64))
return u;
shift = 64 - (__VIRTUAL_MASK_SHIFT + 1);
return (signed long)(u << shift) >> shift;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Kirill A. Shutemov | 25 | 52.08% | 1 | 33.33% |
| Arjan van de Ven | 12 | 25.00% | 1 | 33.33% |
| H. Peter Anvin | 11 | 22.92% | 1 | 33.33% |
| Total | 48 | 100.00% | 3 | 100.00% |
/*
* This function gets called on a break in a continuous series
* of PTE entries; the next one is different so we need to
* print what we collected so far.
*/
static void note_page(struct seq_file *m, struct pg_state *st,
pgprot_t new_prot, int level)
{
pgprotval_t prot, cur;
static const char units[] = "BKMGTPE";
/*
* If we have a "break" in the series, we need to flush the state that
* we have now. "break" is either changing perms, levels or
* address space marker.
*/
prot = pgprot_val(new_prot);
cur = pgprot_val(st->current_prot);
if (!st->level) {
/* First entry */
st->current_prot = new_prot;
st->level = level;
st->marker = address_markers;
st->lines = 0;
pt_dump_seq_printf(m, st->to_dmesg, "---[ %s ]---\n",
st->marker->name);
} else if (prot != cur || level != st->level ||
st->current_address >= st->marker[1].start_address) {
const char *unit = units;
unsigned long delta;
int width = sizeof(unsigned long) * 2;
pgprotval_t pr = pgprot_val(st->current_prot);
if (st->check_wx && (pr & _PAGE_RW) && !(pr & _PAGE_NX)) {
WARN_ONCE(1,
"x86/mm: Found insecure W+X mapping at address %p/%pS\n",
(void *)st->start_address,
(void *)st->start_address);
st->wx_pages += (st->current_address -
st->start_address) / PAGE_SIZE;
}
/*
* Now print the actual finished series
*/
if (!st->marker->max_lines ||
st->lines < st->marker->max_lines) {
pt_dump_seq_printf(m, st->to_dmesg,
"0x%0*lx-0x%0*lx ",
width, st->start_address,
width, st->current_address);
delta = st->current_address - st->start_address;
while (!(delta & 1023) && unit[1]) {
delta >>= 10;
unit++;
}
pt_dump_cont_printf(m, st->to_dmesg, "%9lu%c ",
delta, *unit);
printk_prot(m, st->current_prot, st->level,
st->to_dmesg);
}
st->lines++;
/*
* We print markers for special areas of address space,
* such as the start of vmalloc space etc.
* This helps in the interpretation.
*/
if (st->current_address >= st->marker[1].start_address) {
if (st->marker->max_lines &&
st->lines > st->marker->max_lines) {
unsigned long nskip =
st->lines - st->marker->max_lines;
pt_dump_seq_printf(m, st->to_dmesg,
"... %lu entr%s skipped ... \n",
nskip,
nskip == 1 ? "y" : "ies");
}
st->marker++;
st->lines = 0;
pt_dump_seq_printf(m, st->to_dmesg, "---[ %s ]---\n",
st->marker->name);
}
st->start_address = st->current_address;
st->current_prot = new_prot;
st->level = level;
}
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| H. Peter Anvin | 176 | 38.26% | 2 | 33.33% |
| Arjan van de Ven | 174 | 37.83% | 1 | 16.67% |
| Stephen D. Smalley | 70 | 15.22% | 1 | 16.67% |
| Borislav Petkov | 24 | 5.22% | 1 | 16.67% |
| Yinghai Lu | 16 | 3.48% | 1 | 16.67% |
| Total | 460 | 100.00% | 6 | 100.00% |
static void walk_pte_level(struct seq_file *m, struct pg_state *st, pmd_t addr, unsigned long P)
{
int i;
pte_t *start;
pgprotval_t prot;
start = (pte_t *)pmd_page_vaddr(addr);
for (i = 0; i < PTRS_PER_PTE; i++) {
prot = pte_flags(*start);
st->current_address = normalize_addr(P + i * PTE_LEVEL_MULT);
note_page(m, st, __pgprot(prot), 5);
start++;
}
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Arjan van de Ven | 84 | 86.60% | 1 | 25.00% |
| Toshi Kani | 9 | 9.28% | 1 | 25.00% |
| H. Peter Anvin | 3 | 3.09% | 1 | 25.00% |
| Kirill A. Shutemov | 1 | 1.03% | 1 | 25.00% |
| Total | 97 | 100.00% | 4 | 100.00% |
#ifdef CONFIG_KASAN
/*
* This is an optimization for KASAN=y case. Since all kasan page tables
* eventually point to the kasan_zero_page we could call note_page()
* right away without walking through lower level page tables. This saves
* us dozens of seconds (minutes for 5-level config) while checking for
* W+X mapping or reading kernel_page_tables debugfs file.
*/
static inline bool kasan_page_table(struct seq_file *m, struct pg_state *st,
void *pt)
{
if (__pa(pt) == __pa(kasan_zero_pmd) ||
#ifdef CONFIG_X86_5LEVEL
__pa(pt) == __pa(kasan_zero_p4d) ||
#endif
__pa(pt) == __pa(kasan_zero_pud)) {
pgprotval_t prot = pte_flags(kasan_zero_pte[0]);
note_page(m, st, __pgprot(prot), 5);
return true;
}
return false;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Andrey Ryabinin | 91 | 100.00% | 1 | 100.00% |
| Total | 91 | 100.00% | 1 | 100.00% |
#else
static inline bool kasan_page_table(struct seq_file *m, struct pg_state *st,
void *pt)
{
return false;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Andrey Ryabinin | 24 | 100.00% | 1 | 100.00% |
| Total | 24 | 100.00% | 1 | 100.00% |
#endif
#if PTRS_PER_PMD > 1
static void walk_pmd_level(struct seq_file *m, struct pg_state *st, pud_t addr, unsigned long P)
{
int i;
pmd_t *start, *pmd_start;
pgprotval_t prot;
pmd_start = start = (pmd_t *)pud_page_vaddr(addr);
for (i = 0; i < PTRS_PER_PMD; i++) {
st->current_address = normalize_addr(P + i * PMD_LEVEL_MULT);
if (!pmd_none(*start)) {
if (pmd_large(*start) || !pmd_present(*start)) {
prot = pmd_flags(*start);
note_page(m, st, __pgprot(prot), 4);
} else if (!kasan_page_table(m, st, pmd_start)) {
walk_pte_level(m, st, *start,
P + i * PMD_LEVEL_MULT);
}
} else
note_page(m, st, __pgprot(0), 4);
start++;
}
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Arjan van de Ven | 129 | 73.30% | 1 | 20.00% |
| Andrey Ryabinin | 18 | 10.23% | 1 | 20.00% |
| Toshi Kani | 15 | 8.52% | 1 | 20.00% |
| H. Peter Anvin | 12 | 6.82% | 1 | 20.00% |
| Kirill A. Shutemov | 2 | 1.14% | 1 | 20.00% |
| Total | 176 | 100.00% | 5 | 100.00% |
#else
#define walk_pmd_level(m,s,a,p) walk_pte_level(m,s,__pmd(pud_val(a)),p)
#define pud_large(a) pmd_large(__pmd(pud_val(a)))
#define pud_none(a) pmd_none(__pmd(pud_val(a)))
#endif
#if PTRS_PER_PUD > 1
static void walk_pud_level(struct seq_file *m, struct pg_state *st, p4d_t addr, unsigned long P)
{
int i;
pud_t *start, *pud_start;
pgprotval_t prot;
pud_t *prev_pud = NULL;
pud_start = start = (pud_t *)p4d_page_vaddr(addr);
for (i = 0; i < PTRS_PER_PUD; i++) {
st->current_address = normalize_addr(P + i * PUD_LEVEL_MULT);
if (!pud_none(*start)) {
if (pud_large(*start) || !pud_present(*start)) {
prot = pud_flags(*start);
note_page(m, st, __pgprot(prot), 3);
} else if (!kasan_page_table(m, st, pud_start)) {
walk_pmd_level(m, st, *start,
P + i * PUD_LEVEL_MULT);
}
} else
note_page(m, st, __pgprot(0), 3);
prev_pud = start;
start++;
}
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Arjan van de Ven | 116 | 62.37% | 1 | 14.29% |
| Andrey Ryabinin | 28 | 15.05% | 2 | 28.57% |
| H. Peter Anvin | 23 | 12.37% | 1 | 14.29% |
| Toshi Kani | 15 | 8.06% | 1 | 14.29% |
| Kirill A. Shutemov | 4 | 2.15% | 2 | 28.57% |
| Total | 186 | 100.00% | 7 | 100.00% |
#else
#define walk_pud_level(m,s,a,p) walk_pmd_level(m,s,__pud(p4d_val(a)),p)
#define p4d_large(a) pud_large(__pud(p4d_val(a)))
#define p4d_none(a) pud_none(__pud(p4d_val(a)))
#endif
#if PTRS_PER_P4D > 1
static void walk_p4d_level(struct seq_file *m, struct pg_state *st, pgd_t addr, unsigned long P)
{
int i;
p4d_t *start, *p4d_start;
pgprotval_t prot;
p4d_start = start = (p4d_t *)pgd_page_vaddr(addr);
for (i = 0; i < PTRS_PER_P4D; i++) {
st->current_address = normalize_addr(P + i * P4D_LEVEL_MULT);
if (!p4d_none(*start)) {
if (p4d_large(*start) || !p4d_present(*start)) {
prot = p4d_flags(*start);
note_page(m, st, __pgprot(prot), 2);
} else if (!kasan_page_table(m, st, p4d_start)) {
walk_pud_level(m, st, *start,
P + i * P4D_LEVEL_MULT);
}
} else
note_page(m, st, __pgprot(0), 2);
start++;
}
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Kirill A. Shutemov | 158 | 89.77% | 1 | 50.00% |
| Andrey Ryabinin | 18 | 10.23% | 1 | 50.00% |
| Total | 176 | 100.00% | 2 | 100.00% |
#else
#define walk_p4d_level(m,s,a,p) walk_pud_level(m,s,__p4d(pgd_val(a)),p)
#define pgd_large(a) p4d_large(__p4d(pgd_val(a)))
#define pgd_none(a) p4d_none(__p4d(pgd_val(a)))
#endif
static inline bool is_hypervisor_range(int idx)
{
#ifdef CONFIG_X86_64
/*
* ffff800000000000 - ffff87ffffffffff is reserved for
* the hypervisor.
*/
return (idx >= pgd_index(__PAGE_OFFSET) - 16) &&
(idx < pgd_index(__PAGE_OFFSET));
#else
return false;
#endif
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Boris Ostrovsky | 38 | 90.48% | 1 | 50.00% |
| Borislav Petkov | 4 | 9.52% | 1 | 50.00% |
| Total | 42 | 100.00% | 2 | 100.00% |
static void ptdump_walk_pgd_level_core(struct seq_file *m, pgd_t *pgd,
bool checkwx)
{
#ifdef CONFIG_X86_64
pgd_t *start = (pgd_t *) &init_top_pgt;
#else
pgd_t *start = swapper_pg_dir;
#endif
pgprotval_t prot;
int i;
struct pg_state st = {};
if (pgd) {
start = pgd;
st.to_dmesg = true;
}
st.check_wx = checkwx;
if (checkwx)
st.wx_pages = 0;
for (i = 0; i < PTRS_PER_PGD; i++) {
st.current_address = normalize_addr(i * PGD_LEVEL_MULT);
if (!pgd_none(*start) && !is_hypervisor_range(i)) {
if (pgd_large(*start) || !pgd_present(*start)) {
prot = pgd_flags(*start);
note_page(m, &st, __pgprot(prot), 1);
} else {
walk_p4d_level(m, &st, *start,
i * PGD_LEVEL_MULT);
}
} else
note_page(m, &st, __pgprot(0), 1);
cond_resched();
start++;
}
/* Flush out the last page */
st.current_address = normalize_addr(PTRS_PER_PGD*PGD_LEVEL_MULT);
note_page(m, &st, __pgprot(0), 0);
if (!checkwx)
return;
if (st.wx_pages)
pr_info("x86/mm: Checked W+X mappings: FAILED, %lu W+X pages found.\n",
st.wx_pages);
else
pr_info("x86/mm: Checked W+X mappings: passed, no W+X pages found.\n");
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| H. Peter Anvin | 85 | 32.32% | 1 | 11.11% |
| Arjan van de Ven | 84 | 31.94% | 1 | 11.11% |
| Stephen D. Smalley | 48 | 18.25% | 1 | 11.11% |
| Borislav Petkov | 20 | 7.60% | 1 | 11.11% |
| Toshi Kani | 15 | 5.70% | 1 | 11.11% |
| Boris Ostrovsky | 6 | 2.28% | 1 | 11.11% |
| Andrey Ryabinin | 3 | 1.14% | 1 | 11.11% |
| Kirill A. Shutemov | 2 | 0.76% | 2 | 22.22% |
| Total | 263 | 100.00% | 9 | 100.00% |
void ptdump_walk_pgd_level(struct seq_file *m, pgd_t *pgd)
{
ptdump_walk_pgd_level_core(m, pgd, false);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Stephen D. Smalley | 23 | 100.00% | 1 | 100.00% |
| Total | 23 | 100.00% | 1 | 100.00% |
EXPORT_SYMBOL_GPL(ptdump_walk_pgd_level);
void ptdump_walk_pgd_level_checkwx(void)
{
ptdump_walk_pgd_level_core(NULL, NULL, true);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Stephen D. Smalley | 16 | 100.00% | 1 | 100.00% |
| Total | 16 | 100.00% | 1 | 100.00% |
static int __init pt_dump_init(void)
{
/*
* Various markers are not compile-time constants, so assign them
* here.
*/
#ifdef CONFIG_X86_64
address_markers[LOW_KERNEL_NR].start_address = PAGE_OFFSET;
address_markers[VMALLOC_START_NR].start_address = VMALLOC_START;
address_markers[VMEMMAP_START_NR].start_address = VMEMMAP_START;
#endif
#ifdef CONFIG_X86_32
address_markers[VMALLOC_START_NR].start_address = VMALLOC_START;
address_markers[VMALLOC_END_NR].start_address = VMALLOC_END;
# ifdef CONFIG_HIGHMEM
address_markers[PKMAP_BASE_NR].start_address = PKMAP_BASE;
# endif
address_markers[FIXADDR_START_NR].start_address = FIXADDR_START;
#endif
return 0;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| H. Peter Anvin | 38 | 41.76% | 1 | 14.29% |
| Thomas Garnier | 33 | 36.26% | 1 | 14.29% |
| Arjan van de Ven | 10 | 10.99% | 1 | 14.29% |
| Andres Salomon | 6 | 6.59% | 1 | 14.29% |
| Stephen D. Smalley | 2 | 2.20% | 1 | 14.29% |
| Kees Cook | 1 | 1.10% | 1 | 14.29% |
| Ingo Molnar | 1 | 1.10% | 1 | 14.29% |
| Total | 91 | 100.00% | 7 | 100.00% |
__initcall(pt_dump_init);
Overall Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Arjan van de Ven | 836 | 33.66% | 1 | 3.70% |
| H. Peter Anvin | 613 | 24.68% | 2 | 7.41% |
| Kirill A. Shutemov | 241 | 9.70% | 4 | 14.81% |
| Andrey Ryabinin | 225 | 9.06% | 4 | 14.81% |
| Stephen D. Smalley | 166 | 6.68% | 1 | 3.70% |
| Borislav Petkov | 138 | 5.56% | 2 | 7.41% |
| Toshi Kani | 55 | 2.21% | 1 | 3.70% |
| Andres Salomon | 52 | 2.09% | 1 | 3.70% |
| Boris Ostrovsky | 44 | 1.77% | 1 | 3.70% |
| Thomas Garnier | 39 | 1.57% | 1 | 3.70% |
| Yinghai Lu | 23 | 0.93% | 2 | 7.41% |
| Juergen Gross | 23 | 0.93% | 2 | 7.41% |
| Mathias Krause | 21 | 0.85% | 2 | 7.41% |
| Kees Cook | 6 | 0.24% | 1 | 3.70% |
| Ingo Molnar | 1 | 0.04% | 1 | 3.70% |
| Linus Torvalds | 1 | 0.04% | 1 | 3.70% |
| Total | 2484 | 100.00% | 27 | 100.00% |
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