562 строки
15 KiB
C
562 строки
15 KiB
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;
|
|
};
|
|
|
|
/* Address space markers hints */
|
|
|
|
#ifdef CONFIG_X86_64
|
|
|
|
enum address_markers_idx {
|
|
USER_SPACE_NR = 0,
|
|
KERNEL_SPACE_NR,
|
|
LOW_KERNEL_NR,
|
|
#if defined(CONFIG_MODIFY_LDT_SYSCALL) && defined(CONFIG_X86_5LEVEL)
|
|
LDT_NR,
|
|
#endif
|
|
VMALLOC_START_NR,
|
|
VMEMMAP_START_NR,
|
|
#ifdef CONFIG_KASAN
|
|
KASAN_SHADOW_START_NR,
|
|
KASAN_SHADOW_END_NR,
|
|
#endif
|
|
#if defined(CONFIG_MODIFY_LDT_SYSCALL) && !defined(CONFIG_X86_5LEVEL)
|
|
LDT_NR,
|
|
#endif
|
|
CPU_ENTRY_AREA_NR,
|
|
#ifdef CONFIG_X86_ESPFIX64
|
|
ESPFIX_START_NR,
|
|
#endif
|
|
#ifdef CONFIG_EFI
|
|
EFI_END_NR,
|
|
#endif
|
|
HIGH_KERNEL_NR,
|
|
MODULES_VADDR_NR,
|
|
MODULES_END_NR,
|
|
FIXADDR_START_NR,
|
|
END_OF_SPACE_NR,
|
|
};
|
|
|
|
static struct addr_marker address_markers[] = {
|
|
[USER_SPACE_NR] = { 0, "User Space" },
|
|
[KERNEL_SPACE_NR] = { (1UL << 63), "Kernel Space" },
|
|
[LOW_KERNEL_NR] = { 0UL, "Low Kernel Mapping" },
|
|
[VMALLOC_START_NR] = { 0UL, "vmalloc() Area" },
|
|
[VMEMMAP_START_NR] = { 0UL, "Vmemmap" },
|
|
#ifdef CONFIG_KASAN
|
|
[KASAN_SHADOW_START_NR] = { KASAN_SHADOW_START, "KASAN shadow" },
|
|
[KASAN_SHADOW_END_NR] = { KASAN_SHADOW_END, "KASAN shadow end" },
|
|
#endif
|
|
#ifdef CONFIG_MODIFY_LDT_SYSCALL
|
|
[LDT_NR] = { LDT_BASE_ADDR, "LDT remap" },
|
|
#endif
|
|
[CPU_ENTRY_AREA_NR] = { CPU_ENTRY_AREA_BASE,"CPU entry Area" },
|
|
#ifdef CONFIG_X86_ESPFIX64
|
|
[ESPFIX_START_NR] = { ESPFIX_BASE_ADDR, "ESPfix Area", 16 },
|
|
#endif
|
|
#ifdef CONFIG_EFI
|
|
[EFI_END_NR] = { EFI_VA_END, "EFI Runtime Services" },
|
|
#endif
|
|
[HIGH_KERNEL_NR] = { __START_KERNEL_map, "High Kernel Mapping" },
|
|
[MODULES_VADDR_NR] = { MODULES_VADDR, "Modules" },
|
|
[MODULES_END_NR] = { MODULES_END, "End Modules" },
|
|
[FIXADDR_START_NR] = { FIXADDR_START, "Fixmap Area" },
|
|
[END_OF_SPACE_NR] = { -1, NULL }
|
|
};
|
|
|
|
#else /* CONFIG_X86_64 */
|
|
|
|
enum address_markers_idx {
|
|
USER_SPACE_NR = 0,
|
|
KERNEL_SPACE_NR,
|
|
VMALLOC_START_NR,
|
|
VMALLOC_END_NR,
|
|
#ifdef CONFIG_HIGHMEM
|
|
PKMAP_BASE_NR,
|
|
#endif
|
|
CPU_ENTRY_AREA_NR,
|
|
FIXADDR_START_NR,
|
|
END_OF_SPACE_NR,
|
|
};
|
|
|
|
static struct addr_marker address_markers[] = {
|
|
[USER_SPACE_NR] = { 0, "User Space" },
|
|
[KERNEL_SPACE_NR] = { PAGE_OFFSET, "Kernel Mapping" },
|
|
[VMALLOC_START_NR] = { 0UL, "vmalloc() Area" },
|
|
[VMALLOC_END_NR] = { 0UL, "vmalloc() End" },
|
|
#ifdef CONFIG_HIGHMEM
|
|
[PKMAP_BASE_NR] = { 0UL, "Persistent kmap() Area" },
|
|
#endif
|
|
[CPU_ENTRY_AREA_NR] = { 0UL, "CPU entry area" },
|
|
[FIXADDR_START_NR] = { 0UL, "Fixmap area" },
|
|
[END_OF_SPACE_NR] = { -1, NULL }
|
|
};
|
|
|
|
#endif /* !CONFIG_X86_64 */
|
|
|
|
/* 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 (!(pr & _PAGE_PRESENT)) {
|
|
/* 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]);
|
|
}
|
|
|
|
/*
|
|
* 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;
|
|
}
|
|
|
|
/*
|
|
* 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;
|
|
}
|
|
}
|
|
|
|
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++;
|
|
}
|
|
}
|
|
#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;
|
|
}
|
|
#else
|
|
static inline bool kasan_page_table(struct seq_file *m, struct pg_state *st,
|
|
void *pt)
|
|
{
|
|
return false;
|
|
}
|
|
#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++;
|
|
}
|
|
}
|
|
|
|
#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++;
|
|
}
|
|
}
|
|
|
|
#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++;
|
|
}
|
|
}
|
|
|
|
#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
|
|
}
|
|
|
|
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");
|
|
}
|
|
|
|
void ptdump_walk_pgd_level(struct seq_file *m, pgd_t *pgd)
|
|
{
|
|
ptdump_walk_pgd_level_core(m, pgd, false);
|
|
}
|
|
EXPORT_SYMBOL_GPL(ptdump_walk_pgd_level);
|
|
|
|
void ptdump_walk_pgd_level_checkwx(void)
|
|
{
|
|
ptdump_walk_pgd_level_core(NULL, NULL, true);
|
|
}
|
|
|
|
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;
|
|
address_markers[CPU_ENTRY_AREA_NR].start_address = CPU_ENTRY_AREA_BASE;
|
|
#endif
|
|
return 0;
|
|
}
|
|
__initcall(pt_dump_init);
|