dump_pagetables.c | Explore in Territory

// SPDX-License-Identifier: GPL-2.0-only
/*
 * 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 <[email protected]>
 */

#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 <linux/highmem.h>
#include <linux/pci.h>
#include <linux/ptdump.h>

#include <asm/e820/types.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 { … };

struct addr_marker { … };

/* Address space markers hints */

#ifdef CONFIG_X86_64

enum address_markers_idx { … };

static struct addr_marker address_markers[] = …;

#define INIT_PGD …

#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
#ifdef CONFIG_MODIFY_LDT_SYSCALL
	LDT_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
#ifdef CONFIG_MODIFY_LDT_SYSCALL
	[LDT_NR]		= { 0UL,		"LDT remap" },
#endif
	[CPU_ENTRY_AREA_NR]	= { 0UL,		"CPU entry area" },
	[FIXADDR_START_NR]	= { 0UL,		"Fixmap area" },
	[END_OF_SPACE_NR]	= { -1,			NULL }
};

#define INIT_PGD …

#endif /* !CONFIG_X86_64 */

/* Multipliers for offsets within the PTEs */
#define PTE_LEVEL_MULT …
#define PMD_LEVEL_MULT …
#define PUD_LEVEL_MULT …
#define P4D_LEVEL_MULT …
#define PGD_LEVEL_MULT …

#define pt_dump_seq_printf(m, to_dmesg, fmt, args...) …

#define pt_dump_cont_printf(m, to_dmesg, fmt, args...) …

/*
 * Print a readable form of a pgprot_t to the seq_file
 */
static void printk_prot(struct seq_file *m, pgprotval_t pr, int level, bool dmsg)
{ … }

static void note_wx(struct pg_state *st, unsigned long addr)
{ … }

static void effective_prot(struct ptdump_state *pt_st, int level, u64 val)
{ … }

/*
 * 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 ptdump_state *pt_st, unsigned long addr, int level,
		      u64 val)
{ … }

bool ptdump_walk_pgd_level_core(struct seq_file *m,
				struct mm_struct *mm, pgd_t *pgd,
				bool checkwx, bool dmesg)
{ … }

void ptdump_walk_pgd_level(struct seq_file *m, struct mm_struct *mm)
{ … }

void ptdump_walk_pgd_level_debugfs(struct seq_file *m, struct mm_struct *mm,
				   bool user)
{ … }
EXPORT_SYMBOL_GPL(…);

void ptdump_walk_user_pgd_level_checkwx(void)
{ … }

bool ptdump_walk_pgd_level_checkwx(void)
{ … }

static int __init pt_dump_init(void)
{ … }
__initcall(pt_dump_init);
linux/arch/x86/mm/dump_pagetables.c
