[linux-block.git] / mm / ptdump.c

// SPDX-License-Identifier: GPL-2.0

#include <linux/pagewalk.h>
#include <linux/ptdump.h>
#include <linux/kasan.h>

#ifdef CONFIG_KASAN
/*
 * This is an optimization for KASAN=y case. Since all kasan page tables
 * eventually point to the kasan_early_shadow_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 int note_kasan_page_table(struct mm_walk *walk,
					unsigned long addr)
{
	struct ptdump_state *st = walk->private;

	st->note_page(st, addr, 4, pte_val(kasan_early_shadow_pte[0]));

	walk->action = ACTION_CONTINUE;

	return 0;
}
#endif

static int ptdump_pgd_entry(pgd_t *pgd, unsigned long addr,
			    unsigned long next, struct mm_walk *walk)
{
	struct ptdump_state *st = walk->private;
	pgd_t val = READ_ONCE(*pgd);

#if CONFIG_PGTABLE_LEVELS > 4 && defined(CONFIG_KASAN)
	if (pgd_page(val) == virt_to_page(lm_alias(kasan_early_shadow_p4d)))
		return note_kasan_page_table(walk, addr);
#endif

	if (pgd_leaf(val))
		st->note_page(st, addr, 0, pgd_val(val));

	return 0;
}

static int ptdump_p4d_entry(p4d_t *p4d, unsigned long addr,
			    unsigned long next, struct mm_walk *walk)
{
	struct ptdump_state *st = walk->private;
	p4d_t val = READ_ONCE(*p4d);

#if CONFIG_PGTABLE_LEVELS > 3 && defined(CONFIG_KASAN)
	if (p4d_page(val) == virt_to_page(lm_alias(kasan_early_shadow_pud)))
		return note_kasan_page_table(walk, addr);
#endif

	if (p4d_leaf(val))
		st->note_page(st, addr, 1, p4d_val(val));

	return 0;
}

static int ptdump_pud_entry(pud_t *pud, unsigned long addr,
			    unsigned long next, struct mm_walk *walk)
{
	struct ptdump_state *st = walk->private;
	pud_t val = READ_ONCE(*pud);

#if CONFIG_PGTABLE_LEVELS > 2 && defined(CONFIG_KASAN)
	if (pud_page(val) == virt_to_page(lm_alias(kasan_early_shadow_pmd)))
		return note_kasan_page_table(walk, addr);
#endif

	if (pud_leaf(val))
		st->note_page(st, addr, 2, pud_val(val));

	return 0;
}

static int ptdump_pmd_entry(pmd_t *pmd, unsigned long addr,
			    unsigned long next, struct mm_walk *walk)
{
	struct ptdump_state *st = walk->private;
	pmd_t val = READ_ONCE(*pmd);

#if defined(CONFIG_KASAN)
	if (pmd_page(val) == virt_to_page(lm_alias(kasan_early_shadow_pte)))
		return note_kasan_page_table(walk, addr);
#endif

	if (pmd_leaf(val))
		st->note_page(st, addr, 3, pmd_val(val));

	return 0;
}

static int ptdump_pte_entry(pte_t *pte, unsigned long addr,
			    unsigned long next, struct mm_walk *walk)
{
	struct ptdump_state *st = walk->private;

	st->note_page(st, addr, 4, pte_val(READ_ONCE(*pte)));

	return 0;
}

static int ptdump_hole(unsigned long addr, unsigned long next,
		       int depth, struct mm_walk *walk)
{
	struct ptdump_state *st = walk->private;

	st->note_page(st, addr, depth, 0);

	return 0;
}

static const struct mm_walk_ops ptdump_ops = {
	.pgd_entry	= ptdump_pgd_entry,
	.p4d_entry	= ptdump_p4d_entry,
	.pud_entry	= ptdump_pud_entry,
	.pmd_entry	= ptdump_pmd_entry,
	.pte_entry	= ptdump_pte_entry,
	.pte_hole	= ptdump_hole,
};

void ptdump_walk_pgd(struct ptdump_state *st, struct mm_struct *mm, pgd_t *pgd)
{
	const struct ptdump_range *range = st->range;

	down_read(&mm->mmap_sem);
	while (range->start != range->end) {
		walk_page_range_novma(mm, range->start, range->end,
				      &ptdump_ops, pgd, st);
		range++;
	}
	up_read(&mm->mmap_sem);

	/* Flush out the last page */
	st->note_page(st, 0, -1, 0);
}
Commit	Line	Data
30d621f6 SP	1	// SPDX-License-Identifier: GPL-2.0
	2
	3	#include <linux/pagewalk.h>
	4	#include <linux/ptdump.h>
	5	#include <linux/kasan.h>
	6
	7	#ifdef CONFIG_KASAN
	8	/*
	9	* This is an optimization for KASAN=y case. Since all kasan page tables
	10	* eventually point to the kasan_early_shadow_page we could call note_page()
	11	* right away without walking through lower level page tables. This saves
	12	* us dozens of seconds (minutes for 5-level config) while checking for
	13	* W+X mapping or reading kernel_page_tables debugfs file.
	14	*/
	15	static inline int note_kasan_page_table(struct mm_walk *walk,
	16	unsigned long addr)
	17	{
	18	struct ptdump_state *st = walk->private;
	19
f8f0d0b6	20	st->note_page(st, addr, 4, pte_val(kasan_early_shadow_pte[0]));
30d621f6 SP	21
	22	walk->action = ACTION_CONTINUE;
	23
	24	return 0;
	25	}
	26	#endif
	27
	28	static int ptdump_pgd_entry(pgd_t *pgd, unsigned long addr,
	29	unsigned long next, struct mm_walk *walk)
	30	{
	31	struct ptdump_state *st = walk->private;
	32	pgd_t val = READ_ONCE(*pgd);
	33
	34	#if CONFIG_PGTABLE_LEVELS > 4 && defined(CONFIG_KASAN)
	35	if (pgd_page(val) == virt_to_page(lm_alias(kasan_early_shadow_p4d)))
	36	return note_kasan_page_table(walk, addr);
	37	#endif
	38
	39	if (pgd_leaf(val))
f8f0d0b6	40	st->note_page(st, addr, 0, pgd_val(val));
30d621f6 SP	41
	42	return 0;
	43	}
	44
	45	static int ptdump_p4d_entry(p4d_t *p4d, unsigned long addr,
	46	unsigned long next, struct mm_walk *walk)
	47	{
	48	struct ptdump_state *st = walk->private;
	49	p4d_t val = READ_ONCE(*p4d);
	50
	51	#if CONFIG_PGTABLE_LEVELS > 3 && defined(CONFIG_KASAN)
	52	if (p4d_page(val) == virt_to_page(lm_alias(kasan_early_shadow_pud)))
	53	return note_kasan_page_table(walk, addr);
	54	#endif
	55
	56	if (p4d_leaf(val))
f8f0d0b6	57	st->note_page(st, addr, 1, p4d_val(val));
30d621f6 SP	58
	59	return 0;
	60	}
	61
	62	static int ptdump_pud_entry(pud_t *pud, unsigned long addr,
	63	unsigned long next, struct mm_walk *walk)
	64	{
	65	struct ptdump_state *st = walk->private;
	66	pud_t val = READ_ONCE(*pud);
	67
	68	#if CONFIG_PGTABLE_LEVELS > 2 && defined(CONFIG_KASAN)
	69	if (pud_page(val) == virt_to_page(lm_alias(kasan_early_shadow_pmd)))
	70	return note_kasan_page_table(walk, addr);
	71	#endif
	72
	73	if (pud_leaf(val))
f8f0d0b6	74	st->note_page(st, addr, 2, pud_val(val));
30d621f6 SP	75
	76	return 0;
	77	}
	78
	79	static int ptdump_pmd_entry(pmd_t *pmd, unsigned long addr,
	80	unsigned long next, struct mm_walk *walk)
	81	{
	82	struct ptdump_state *st = walk->private;
	83	pmd_t val = READ_ONCE(*pmd);
	84
	85	#if defined(CONFIG_KASAN)
	86	if (pmd_page(val) == virt_to_page(lm_alias(kasan_early_shadow_pte)))
	87	return note_kasan_page_table(walk, addr);
	88	#endif
	89
	90	if (pmd_leaf(val))
f8f0d0b6	91	st->note_page(st, addr, 3, pmd_val(val));
30d621f6 SP	92
	93	return 0;
	94	}
	95
	96	static int ptdump_pte_entry(pte_t *pte, unsigned long addr,
	97	unsigned long next, struct mm_walk *walk)
	98	{
	99	struct ptdump_state *st = walk->private;
	100
f8f0d0b6	101	st->note_page(st, addr, 4, pte_val(READ_ONCE(*pte)));
30d621f6 SP	102
	103	return 0;
	104	}
	105
	106	static int ptdump_hole(unsigned long addr, unsigned long next,
	107	int depth, struct mm_walk *walk)
	108	{
	109	struct ptdump_state *st = walk->private;
	110
f8f0d0b6	111	st->note_page(st, addr, depth, 0);
30d621f6 SP	112
	113	return 0;
	114	}
	115
	116	static const struct mm_walk_ops ptdump_ops = {
	117	.pgd_entry = ptdump_pgd_entry,
	118	.p4d_entry = ptdump_p4d_entry,
	119	.pud_entry = ptdump_pud_entry,
	120	.pmd_entry = ptdump_pmd_entry,
	121	.pte_entry = ptdump_pte_entry,
	122	.pte_hole = ptdump_hole,
	123	};
	124
e47690d7	125	void ptdump_walk_pgd(struct ptdump_state st, struct mm_struct mm, pgd_t *pgd)
30d621f6 SP	126	{
	127	const struct ptdump_range *range = st->range;
	128
	129	down_read(&mm->mmap_sem);
	130	while (range->start != range->end) {
	131	walk_page_range_novma(mm, range->start, range->end,
e47690d7	132	&ptdump_ops, pgd, st);
30d621f6 SP	133	range++;
	134	}
	135	up_read(&mm->mmap_sem);
	136
	137	/* Flush out the last page */
f8f0d0b6	138	st->note_page(st, 0, -1, 0);
30d621f6	139	}