[thirdparty/linux.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 (st->effective_prot)
		st->effective_prot(st, 0, pgd_val(val));

	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 (st->effective_prot)
		st->effective_prot(st, 1, p4d_val(val));

	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 (st->effective_prot)
		st->effective_prot(st, 2, pud_val(val));

	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 (st->effective_prot)
		st->effective_prot(st, 3, pmd_val(val));
	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;
	pte_t val = READ_ONCE(*pte);

	if (st->effective_prot)
		st->effective_prot(st, 4, pte_val(val));

	st->note_page(st, addr, 4, pte_val(val));

	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
1494e0c3 SP	39	if (st->effective_prot)
	40	st->effective_prot(st, 0, pgd_val(val));
	41
30d621f6	42	if (pgd_leaf(val))
f8f0d0b6	43	st->note_page(st, addr, 0, pgd_val(val));
30d621f6 SP	44
	45	return 0;
	46	}
	47
	48	static int ptdump_p4d_entry(p4d_t *p4d, unsigned long addr,
	49	unsigned long next, struct mm_walk *walk)
	50	{
	51	struct ptdump_state *st = walk->private;
	52	p4d_t val = READ_ONCE(*p4d);
	53
	54	#if CONFIG_PGTABLE_LEVELS > 3 && defined(CONFIG_KASAN)
	55	if (p4d_page(val) == virt_to_page(lm_alias(kasan_early_shadow_pud)))
	56	return note_kasan_page_table(walk, addr);
	57	#endif
	58
1494e0c3 SP	59	if (st->effective_prot)
	60	st->effective_prot(st, 1, p4d_val(val));
	61
30d621f6	62	if (p4d_leaf(val))
f8f0d0b6	63	st->note_page(st, addr, 1, p4d_val(val));
30d621f6 SP	64
	65	return 0;
	66	}
	67
	68	static int ptdump_pud_entry(pud_t *pud, unsigned long addr,
	69	unsigned long next, struct mm_walk *walk)
	70	{
	71	struct ptdump_state *st = walk->private;
	72	pud_t val = READ_ONCE(*pud);
	73
	74	#if CONFIG_PGTABLE_LEVELS > 2 && defined(CONFIG_KASAN)
	75	if (pud_page(val) == virt_to_page(lm_alias(kasan_early_shadow_pmd)))
	76	return note_kasan_page_table(walk, addr);
	77	#endif
	78
1494e0c3 SP	79	if (st->effective_prot)
	80	st->effective_prot(st, 2, pud_val(val));
	81
30d621f6	82	if (pud_leaf(val))
f8f0d0b6	83	st->note_page(st, addr, 2, pud_val(val));
30d621f6 SP	84
	85	return 0;
	86	}
	87
	88	static int ptdump_pmd_entry(pmd_t *pmd, unsigned long addr,
	89	unsigned long next, struct mm_walk *walk)
	90	{
	91	struct ptdump_state *st = walk->private;
	92	pmd_t val = READ_ONCE(*pmd);
	93
	94	#if defined(CONFIG_KASAN)
	95	if (pmd_page(val) == virt_to_page(lm_alias(kasan_early_shadow_pte)))
	96	return note_kasan_page_table(walk, addr);
	97	#endif
	98
1494e0c3 SP	99	if (st->effective_prot)
1494e0c3 SP	100	st->effective_prot(st, 3, pmd_val(val));
30d621f6	101	if (pmd_leaf(val))
f8f0d0b6	102	st->note_page(st, addr, 3, pmd_val(val));
30d621f6 SP	103
	104	return 0;
	105	}
	106
	107	static int ptdump_pte_entry(pte_t *pte, unsigned long addr,
	108	unsigned long next, struct mm_walk *walk)
	109	{
	110	struct ptdump_state *st = walk->private;
1494e0c3 SP	111	pte_t val = READ_ONCE(*pte);
	112
	113	if (st->effective_prot)
	114	st->effective_prot(st, 4, pte_val(val));
30d621f6	115
1494e0c3	116	st->note_page(st, addr, 4, pte_val(val));
30d621f6 SP	117
	118	return 0;
	119	}
	120
	121	static int ptdump_hole(unsigned long addr, unsigned long next,
	122	int depth, struct mm_walk *walk)
	123	{
	124	struct ptdump_state *st = walk->private;
	125
f8f0d0b6	126	st->note_page(st, addr, depth, 0);
30d621f6 SP	127
	128	return 0;
	129	}
	130
	131	static const struct mm_walk_ops ptdump_ops = {
	132	.pgd_entry = ptdump_pgd_entry,
	133	.p4d_entry = ptdump_p4d_entry,
	134	.pud_entry = ptdump_pud_entry,
	135	.pmd_entry = ptdump_pmd_entry,
	136	.pte_entry = ptdump_pte_entry,
	137	.pte_hole = ptdump_hole,
	138	};
	139
e47690d7	140	void ptdump_walk_pgd(struct ptdump_state st, struct mm_struct mm, pgd_t *pgd)
30d621f6 SP	141	{
	142	const struct ptdump_range *range = st->range;
	143
	144	down_read(&mm->mmap_sem);
	145	while (range->start != range->end) {
	146	walk_page_range_novma(mm, range->start, range->end,
e47690d7	147	&ptdump_ops, pgd, st);
30d621f6 SP	148	range++;
	149	}
	150	up_read(&mm->mmap_sem);
	151
	152	/* Flush out the last page */
f8f0d0b6	153	st->note_page(st, 0, -1, 0);
30d621f6	154	}