[mirror_ubuntu-jammy-kernel.git] / mm / kasan / init.c

// SPDX-License-Identifier: GPL-2.0
/*
 * This file contains KASAN shadow initialization code.
 *
 * Copyright (c) 2015 Samsung Electronics Co., Ltd.
 * Author: Andrey Ryabinin <ryabinin.a.a@gmail.com>
 */

#include <linux/memblock.h>
#include <linux/init.h>
#include <linux/kasan.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/pfn.h>
#include <linux/slab.h>

#include <asm/page.h>
#include <asm/pgalloc.h>

#include "kasan.h"

/*
 * This page serves two purposes:
 *   - It used as early shadow memory. The entire shadow region populated
 *     with this page, before we will be able to setup normal shadow memory.
 *   - Latter it reused it as zero shadow to cover large ranges of memory
 *     that allowed to access, but not handled by kasan (vmalloc/vmemmap ...).
 */
unsigned char kasan_early_shadow_page[PAGE_SIZE] __page_aligned_bss;

#if CONFIG_PGTABLE_LEVELS > 4
p4d_t kasan_early_shadow_p4d[MAX_PTRS_PER_P4D] __page_aligned_bss;
static inline bool kasan_p4d_table(pgd_t pgd)
{
	return pgd_page(pgd) == virt_to_page(lm_alias(kasan_early_shadow_p4d));
}
#else
static inline bool kasan_p4d_table(pgd_t pgd)
{
	return false;
}
#endif
#if CONFIG_PGTABLE_LEVELS > 3
pud_t kasan_early_shadow_pud[PTRS_PER_PUD] __page_aligned_bss;
static inline bool kasan_pud_table(p4d_t p4d)
{
	return p4d_page(p4d) == virt_to_page(lm_alias(kasan_early_shadow_pud));
}
#else
static inline bool kasan_pud_table(p4d_t p4d)
{
	return false;
}
#endif
#if CONFIG_PGTABLE_LEVELS > 2
pmd_t kasan_early_shadow_pmd[PTRS_PER_PMD] __page_aligned_bss;
static inline bool kasan_pmd_table(pud_t pud)
{
	return pud_page(pud) == virt_to_page(lm_alias(kasan_early_shadow_pmd));
}
#else
static inline bool kasan_pmd_table(pud_t pud)
{
	return false;
}
#endif
pte_t kasan_early_shadow_pte[PTRS_PER_PTE] __page_aligned_bss;

static inline bool kasan_pte_table(pmd_t pmd)
{
	return pmd_page(pmd) == virt_to_page(lm_alias(kasan_early_shadow_pte));
}

static inline bool kasan_early_shadow_page_entry(pte_t pte)
{
	return pte_page(pte) == virt_to_page(lm_alias(kasan_early_shadow_page));
}

static __init void *early_alloc(size_t size, int node)
{
	void *ptr = memblock_alloc_try_nid(size, size, __pa(MAX_DMA_ADDRESS),
					   MEMBLOCK_ALLOC_ACCESSIBLE, node);

	if (!ptr)
		panic("%s: Failed to allocate %zu bytes align=%zx nid=%d from=%llx\n",
		      __func__, size, size, node, (u64)__pa(MAX_DMA_ADDRESS));

	return ptr;
}

static void __ref zero_pte_populate(pmd_t *pmd, unsigned long addr,
				unsigned long end)
{
	pte_t *pte = pte_offset_kernel(pmd, addr);
	pte_t zero_pte;

	zero_pte = pfn_pte(PFN_DOWN(__pa_symbol(kasan_early_shadow_page)),
				PAGE_KERNEL);
	zero_pte = pte_wrprotect(zero_pte);

	while (addr + PAGE_SIZE <= end) {
		set_pte_at(&init_mm, addr, pte, zero_pte);
		addr += PAGE_SIZE;
		pte = pte_offset_kernel(pmd, addr);
	}
}

static int __ref zero_pmd_populate(pud_t *pud, unsigned long addr,
				unsigned long end)
{
	pmd_t *pmd = pmd_offset(pud, addr);
	unsigned long next;

	do {
		next = pmd_addr_end(addr, end);

		if (IS_ALIGNED(addr, PMD_SIZE) && end - addr >= PMD_SIZE) {
			pmd_populate_kernel(&init_mm, pmd,
					lm_alias(kasan_early_shadow_pte));
			continue;
		}

		if (pmd_none(*pmd)) {
			pte_t *p;

			if (slab_is_available())
				p = pte_alloc_one_kernel(&init_mm);
			else
				p = early_alloc(PAGE_SIZE, NUMA_NO_NODE);
			if (!p)
				return -ENOMEM;

			pmd_populate_kernel(&init_mm, pmd, p);
		}
		zero_pte_populate(pmd, addr, next);
	} while (pmd++, addr = next, addr != end);

	return 0;
}

static int __ref zero_pud_populate(p4d_t *p4d, unsigned long addr,
				unsigned long end)
{
	pud_t *pud = pud_offset(p4d, addr);
	unsigned long next;

	do {
		next = pud_addr_end(addr, end);
		if (IS_ALIGNED(addr, PUD_SIZE) && end - addr >= PUD_SIZE) {
			pmd_t *pmd;

			pud_populate(&init_mm, pud,
					lm_alias(kasan_early_shadow_pmd));
			pmd = pmd_offset(pud, addr);
			pmd_populate_kernel(&init_mm, pmd,
					lm_alias(kasan_early_shadow_pte));
			continue;
		}

		if (pud_none(*pud)) {
			pmd_t *p;

			if (slab_is_available()) {
				p = pmd_alloc(&init_mm, pud, addr);
				if (!p)
					return -ENOMEM;
			} else {
				pud_populate(&init_mm, pud,
					early_alloc(PAGE_SIZE, NUMA_NO_NODE));
			}
		}
		zero_pmd_populate(pud, addr, next);
	} while (pud++, addr = next, addr != end);

	return 0;
}

static int __ref zero_p4d_populate(pgd_t *pgd, unsigned long addr,
				unsigned long end)
{
	p4d_t *p4d = p4d_offset(pgd, addr);
	unsigned long next;

	do {
		next = p4d_addr_end(addr, end);
		if (IS_ALIGNED(addr, P4D_SIZE) && end - addr >= P4D_SIZE) {
			pud_t *pud;
			pmd_t *pmd;

			p4d_populate(&init_mm, p4d,
					lm_alias(kasan_early_shadow_pud));
			pud = pud_offset(p4d, addr);
			pud_populate(&init_mm, pud,
					lm_alias(kasan_early_shadow_pmd));
			pmd = pmd_offset(pud, addr);
			pmd_populate_kernel(&init_mm, pmd,
					lm_alias(kasan_early_shadow_pte));
			continue;
		}

		if (p4d_none(*p4d)) {
			pud_t *p;

			if (slab_is_available()) {
				p = pud_alloc(&init_mm, p4d, addr);
				if (!p)
					return -ENOMEM;
			} else {
				p4d_populate(&init_mm, p4d,
					early_alloc(PAGE_SIZE, NUMA_NO_NODE));
			}
		}
		zero_pud_populate(p4d, addr, next);
	} while (p4d++, addr = next, addr != end);

	return 0;
}

/**
 * kasan_populate_early_shadow - populate shadow memory region with
 *                               kasan_early_shadow_page
 * @shadow_start - start of the memory range to populate
 * @shadow_end   - end of the memory range to populate
 */
int __ref kasan_populate_early_shadow(const void *shadow_start,
					const void *shadow_end)
{
	unsigned long addr = (unsigned long)shadow_start;
	unsigned long end = (unsigned long)shadow_end;
	pgd_t *pgd = pgd_offset_k(addr);
	unsigned long next;

	do {
		next = pgd_addr_end(addr, end);

		if (IS_ALIGNED(addr, PGDIR_SIZE) && end - addr >= PGDIR_SIZE) {
			p4d_t *p4d;
			pud_t *pud;
			pmd_t *pmd;

			/*
			 * kasan_early_shadow_pud should be populated with pmds
			 * at this moment.
			 * [pud,pmd]_populate*() below needed only for
			 * 3,2 - level page tables where we don't have
			 * puds,pmds, so pgd_populate(), pud_populate()
			 * is noops.
			 */
			pgd_populate(&init_mm, pgd,
					lm_alias(kasan_early_shadow_p4d));
			p4d = p4d_offset(pgd, addr);
			p4d_populate(&init_mm, p4d,
					lm_alias(kasan_early_shadow_pud));
			pud = pud_offset(p4d, addr);
			pud_populate(&init_mm, pud,
					lm_alias(kasan_early_shadow_pmd));
			pmd = pmd_offset(pud, addr);
			pmd_populate_kernel(&init_mm, pmd,
					lm_alias(kasan_early_shadow_pte));
			continue;
		}

		if (pgd_none(*pgd)) {
			p4d_t *p;

			if (slab_is_available()) {
				p = p4d_alloc(&init_mm, pgd, addr);
				if (!p)
					return -ENOMEM;
			} else {
				pgd_populate(&init_mm, pgd,
					early_alloc(PAGE_SIZE, NUMA_NO_NODE));
			}
		}
		zero_p4d_populate(pgd, addr, next);
	} while (pgd++, addr = next, addr != end);

	return 0;
}

static void kasan_free_pte(pte_t *pte_start, pmd_t *pmd)
{
	pte_t *pte;
	int i;

	for (i = 0; i < PTRS_PER_PTE; i++) {
		pte = pte_start + i;
		if (!pte_none(*pte))
			return;
	}

	pte_free_kernel(&init_mm, (pte_t *)page_to_virt(pmd_page(*pmd)));
	pmd_clear(pmd);
}

static void kasan_free_pmd(pmd_t *pmd_start, pud_t *pud)
{
	pmd_t *pmd;
	int i;

	for (i = 0; i < PTRS_PER_PMD; i++) {
		pmd = pmd_start + i;
		if (!pmd_none(*pmd))
			return;
	}

	pmd_free(&init_mm, (pmd_t *)page_to_virt(pud_page(*pud)));
	pud_clear(pud);
}

static void kasan_free_pud(pud_t *pud_start, p4d_t *p4d)
{
	pud_t *pud;
	int i;

	for (i = 0; i < PTRS_PER_PUD; i++) {
		pud = pud_start + i;
		if (!pud_none(*pud))
			return;
	}

	pud_free(&init_mm, (pud_t *)page_to_virt(p4d_page(*p4d)));
	p4d_clear(p4d);
}

static void kasan_free_p4d(p4d_t *p4d_start, pgd_t *pgd)
{
	p4d_t *p4d;
	int i;

	for (i = 0; i < PTRS_PER_P4D; i++) {
		p4d = p4d_start + i;
		if (!p4d_none(*p4d))
			return;
	}

	p4d_free(&init_mm, (p4d_t *)page_to_virt(pgd_page(*pgd)));
	pgd_clear(pgd);
}

static void kasan_remove_pte_table(pte_t *pte, unsigned long addr,
				unsigned long end)
{
	unsigned long next;

	for (; addr < end; addr = next, pte++) {
		next = (addr + PAGE_SIZE) & PAGE_MASK;
		if (next > end)
			next = end;

		if (!pte_present(*pte))
			continue;

		if (WARN_ON(!kasan_early_shadow_page_entry(*pte)))
			continue;
		pte_clear(&init_mm, addr, pte);
	}
}

static void kasan_remove_pmd_table(pmd_t *pmd, unsigned long addr,
				unsigned long end)
{
	unsigned long next;

	for (; addr < end; addr = next, pmd++) {
		pte_t *pte;

		next = pmd_addr_end(addr, end);

		if (!pmd_present(*pmd))
			continue;

		if (kasan_pte_table(*pmd)) {
			if (IS_ALIGNED(addr, PMD_SIZE) &&
			    IS_ALIGNED(next, PMD_SIZE))
				pmd_clear(pmd);
			continue;
		}
		pte = pte_offset_kernel(pmd, addr);
		kasan_remove_pte_table(pte, addr, next);
		kasan_free_pte(pte_offset_kernel(pmd, 0), pmd);
	}
}

static void kasan_remove_pud_table(pud_t *pud, unsigned long addr,
				unsigned long end)
{
	unsigned long next;

	for (; addr < end; addr = next, pud++) {
		pmd_t *pmd, *pmd_base;

		next = pud_addr_end(addr, end);

		if (!pud_present(*pud))
			continue;

		if (kasan_pmd_table(*pud)) {
			if (IS_ALIGNED(addr, PUD_SIZE) &&
			    IS_ALIGNED(next, PUD_SIZE))
				pud_clear(pud);
			continue;
		}
		pmd = pmd_offset(pud, addr);
		pmd_base = pmd_offset(pud, 0);
		kasan_remove_pmd_table(pmd, addr, next);
		kasan_free_pmd(pmd_base, pud);
	}
}

static void kasan_remove_p4d_table(p4d_t *p4d, unsigned long addr,
				unsigned long end)
{
	unsigned long next;

	for (; addr < end; addr = next, p4d++) {
		pud_t *pud;

		next = p4d_addr_end(addr, end);

		if (!p4d_present(*p4d))
			continue;

		if (kasan_pud_table(*p4d)) {
			if (IS_ALIGNED(addr, P4D_SIZE) &&
			    IS_ALIGNED(next, P4D_SIZE))
				p4d_clear(p4d);
			continue;
		}
		pud = pud_offset(p4d, addr);
		kasan_remove_pud_table(pud, addr, next);
		kasan_free_pud(pud_offset(p4d, 0), p4d);
	}
}

void kasan_remove_zero_shadow(void *start, unsigned long size)
{
	unsigned long addr, end, next;
	pgd_t *pgd;

	addr = (unsigned long)kasan_mem_to_shadow(start);
	end = addr + (size >> KASAN_SHADOW_SCALE_SHIFT);

	if (WARN_ON((unsigned long)start % KASAN_MEMORY_PER_SHADOW_PAGE) ||
	    WARN_ON(size % KASAN_MEMORY_PER_SHADOW_PAGE))
		return;

	for (; addr < end; addr = next) {
		p4d_t *p4d;

		next = pgd_addr_end(addr, end);

		pgd = pgd_offset_k(addr);
		if (!pgd_present(*pgd))
			continue;

		if (kasan_p4d_table(*pgd)) {
			if (IS_ALIGNED(addr, PGDIR_SIZE) &&
			    IS_ALIGNED(next, PGDIR_SIZE))
				pgd_clear(pgd);
			continue;
		}

		p4d = p4d_offset(pgd, addr);
		kasan_remove_p4d_table(p4d, addr, next);
		kasan_free_p4d(p4d_offset(pgd, 0), pgd);
	}
}

int kasan_add_zero_shadow(void *start, unsigned long size)
{
	int ret;
	void *shadow_start, *shadow_end;

	shadow_start = kasan_mem_to_shadow(start);
	shadow_end = shadow_start + (size >> KASAN_SHADOW_SCALE_SHIFT);

	if (WARN_ON((unsigned long)start % KASAN_MEMORY_PER_SHADOW_PAGE) ||
	    WARN_ON(size % KASAN_MEMORY_PER_SHADOW_PAGE))
		return -EINVAL;

	ret = kasan_populate_early_shadow(shadow_start, shadow_end);
	if (ret)
		kasan_remove_zero_shadow(shadow_start,
					size >> KASAN_SHADOW_SCALE_SHIFT);
	return ret;
}
Commit	Line	Data
e886bf9d	1	// SPDX-License-Identifier: GPL-2.0
69786cdb	2	/*
b266e8fe	3	* This file contains KASAN shadow initialization code.
69786cdb AR	4	*
	5	* Copyright (c) 2015 Samsung Electronics Co., Ltd.
	6	* Author: Andrey Ryabinin <ryabinin.a.a@gmail.com>
69786cdb AR	7	*/
69786cdb AR	8
57c8a661	9	#include <linux/memblock.h>
69786cdb AR	10	#include <linux/init.h>
	11	#include <linux/kasan.h>
	12	#include <linux/kernel.h>
5c6a84a3	13	#include <linux/mm.h>
69786cdb	14	#include <linux/pfn.h>
0207df4f	15	#include <linux/slab.h>
69786cdb AR	16
	17	#include <asm/page.h>
	18	#include <asm/pgalloc.h>
	19
0207df4f AR	20	#include "kasan.h"
0207df4f AR	21
69786cdb AR	22	/*
	23	* This page serves two purposes:
	24	* - It used as early shadow memory. The entire shadow region populated
	25	* with this page, before we will be able to setup normal shadow memory.
	26	* - Latter it reused it as zero shadow to cover large ranges of memory
	27	* that allowed to access, but not handled by kasan (vmalloc/vmemmap ...).
	28	*/
9577dd74	29	unsigned char kasan_early_shadow_page[PAGE_SIZE] __page_aligned_bss;
69786cdb	30
c2febafc	31	#if CONFIG_PGTABLE_LEVELS > 4
9577dd74	32	p4d_t kasan_early_shadow_p4d[MAX_PTRS_PER_P4D] __page_aligned_bss;
0207df4f AR	33	static inline bool kasan_p4d_table(pgd_t pgd)
0207df4f AR	34	{
9577dd74	35	return pgd_page(pgd) == virt_to_page(lm_alias(kasan_early_shadow_p4d));
0207df4f AR	36	}
	37	#else
	38	static inline bool kasan_p4d_table(pgd_t pgd)
	39	{
5c0198b6	40	return false;
0207df4f	41	}
c2febafc	42	#endif
69786cdb	43	#if CONFIG_PGTABLE_LEVELS > 3
9577dd74	44	pud_t kasan_early_shadow_pud[PTRS_PER_PUD] __page_aligned_bss;
0207df4f AR	45	static inline bool kasan_pud_table(p4d_t p4d)
0207df4f AR	46	{
9577dd74	47	return p4d_page(p4d) == virt_to_page(lm_alias(kasan_early_shadow_pud));
0207df4f AR	48	}
	49	#else
	50	static inline bool kasan_pud_table(p4d_t p4d)
	51	{
5c0198b6	52	return false;
0207df4f	53	}
69786cdb AR	54	#endif
69786cdb AR	55	#if CONFIG_PGTABLE_LEVELS > 2
9577dd74	56	pmd_t kasan_early_shadow_pmd[PTRS_PER_PMD] __page_aligned_bss;
0207df4f AR	57	static inline bool kasan_pmd_table(pud_t pud)
0207df4f AR	58	{
9577dd74	59	return pud_page(pud) == virt_to_page(lm_alias(kasan_early_shadow_pmd));
0207df4f AR	60	}
	61	#else
	62	static inline bool kasan_pmd_table(pud_t pud)
	63	{
5c0198b6	64	return false;
0207df4f	65	}
69786cdb	66	#endif
9577dd74	67	pte_t kasan_early_shadow_pte[PTRS_PER_PTE] __page_aligned_bss;
69786cdb	68
0207df4f AR	69	static inline bool kasan_pte_table(pmd_t pmd)
0207df4f AR	70	{
9577dd74	71	return pmd_page(pmd) == virt_to_page(lm_alias(kasan_early_shadow_pte));
0207df4f AR	72	}
0207df4f AR	73
9577dd74	74	static inline bool kasan_early_shadow_page_entry(pte_t pte)
0207df4f	75	{
9577dd74	76	return pte_page(pte) == virt_to_page(lm_alias(kasan_early_shadow_page));
0207df4f AR	77	}
0207df4f AR	78
69786cdb AR	79	static __init void *early_alloc(size_t size, int node)
69786cdb AR	80	{
8a7f97b9 MR	81	void *ptr = memblock_alloc_try_nid(size, size, __pa(MAX_DMA_ADDRESS),
	82	MEMBLOCK_ALLOC_ACCESSIBLE, node);
	83
	84	if (!ptr)
	85	panic("%s: Failed to allocate %zu bytes align=%zx nid=%d from=%llx\n",
	86	__func__, size, size, node, (u64)__pa(MAX_DMA_ADDRESS));
	87
	88	return ptr;
69786cdb AR	89	}
69786cdb AR	90
0207df4f	91	static void __ref zero_pte_populate(pmd_t *pmd, unsigned long addr,
69786cdb AR	92	unsigned long end)
	93	{
	94	pte_t *pte = pte_offset_kernel(pmd, addr);
	95	pte_t zero_pte;
	96
9577dd74 AK	97	zero_pte = pfn_pte(PFN_DOWN(__pa_symbol(kasan_early_shadow_page)),
9577dd74 AK	98	PAGE_KERNEL);
69786cdb AR	99	zero_pte = pte_wrprotect(zero_pte);
	100
	101	while (addr + PAGE_SIZE <= end) {
	102	set_pte_at(&init_mm, addr, pte, zero_pte);
	103	addr += PAGE_SIZE;
	104	pte = pte_offset_kernel(pmd, addr);
	105	}
	106	}
	107
0207df4f	108	static int __ref zero_pmd_populate(pud_t *pud, unsigned long addr,
69786cdb AR	109	unsigned long end)
	110	{
	111	pmd_t *pmd = pmd_offset(pud, addr);
	112	unsigned long next;
	113
	114	do {
	115	next = pmd_addr_end(addr, end);
	116
	117	if (IS_ALIGNED(addr, PMD_SIZE) && end - addr >= PMD_SIZE) {
9577dd74 AK	118	pmd_populate_kernel(&init_mm, pmd,
9577dd74 AK	119	lm_alias(kasan_early_shadow_pte));
69786cdb AR	120	continue;
	121	}
	122
	123	if (pmd_none(*pmd)) {
0207df4f AR	124	pte_t *p;
	125
	126	if (slab_is_available())
4cf58924	127	p = pte_alloc_one_kernel(&init_mm);
0207df4f AR	128	else
	129	p = early_alloc(PAGE_SIZE, NUMA_NO_NODE);
	130	if (!p)
	131	return -ENOMEM;
	132
	133	pmd_populate_kernel(&init_mm, pmd, p);
69786cdb AR	134	}
	135	zero_pte_populate(pmd, addr, next);
	136	} while (pmd++, addr = next, addr != end);
0207df4f AR	137
0207df4f AR	138	return 0;
69786cdb AR	139	}
69786cdb AR	140
0207df4f	141	static int __ref zero_pud_populate(p4d_t *p4d, unsigned long addr,
69786cdb AR	142	unsigned long end)
69786cdb AR	143	{
c2febafc	144	pud_t *pud = pud_offset(p4d, addr);
69786cdb AR	145	unsigned long next;
	146
	147	do {
	148	next = pud_addr_end(addr, end);
	149	if (IS_ALIGNED(addr, PUD_SIZE) && end - addr >= PUD_SIZE) {
	150	pmd_t *pmd;
	151
9577dd74 AK	152	pud_populate(&init_mm, pud,
9577dd74 AK	153	lm_alias(kasan_early_shadow_pmd));
69786cdb	154	pmd = pmd_offset(pud, addr);
9577dd74 AK	155	pmd_populate_kernel(&init_mm, pmd,
9577dd74 AK	156	lm_alias(kasan_early_shadow_pte));
69786cdb AR	157	continue;
	158	}
	159
	160	if (pud_none(*pud)) {
0207df4f AR	161	pmd_t *p;
	162
	163	if (slab_is_available()) {
	164	p = pmd_alloc(&init_mm, pud, addr);
	165	if (!p)
	166	return -ENOMEM;
	167	} else {
	168	pud_populate(&init_mm, pud,
	169	early_alloc(PAGE_SIZE, NUMA_NO_NODE));
	170	}
69786cdb AR	171	}
	172	zero_pmd_populate(pud, addr, next);
	173	} while (pud++, addr = next, addr != end);
0207df4f AR	174
0207df4f AR	175	return 0;
69786cdb AR	176	}
69786cdb AR	177
0207df4f	178	static int __ref zero_p4d_populate(pgd_t *pgd, unsigned long addr,
c2febafc KS	179	unsigned long end)
	180	{
	181	p4d_t *p4d = p4d_offset(pgd, addr);
	182	unsigned long next;
	183
	184	do {
	185	next = p4d_addr_end(addr, end);
458f7920 JK	186	if (IS_ALIGNED(addr, P4D_SIZE) && end - addr >= P4D_SIZE) {
	187	pud_t *pud;
	188	pmd_t *pmd;
	189
9577dd74 AK	190	p4d_populate(&init_mm, p4d,
9577dd74 AK	191	lm_alias(kasan_early_shadow_pud));
458f7920	192	pud = pud_offset(p4d, addr);
9577dd74 AK	193	pud_populate(&init_mm, pud,
9577dd74 AK	194	lm_alias(kasan_early_shadow_pmd));
458f7920 JK	195	pmd = pmd_offset(pud, addr);
458f7920 JK	196	pmd_populate_kernel(&init_mm, pmd,
9577dd74	197	lm_alias(kasan_early_shadow_pte));
458f7920 JK	198	continue;
458f7920 JK	199	}
c2febafc KS	200
c2febafc KS	201	if (p4d_none(*p4d)) {
0207df4f AR	202	pud_t *p;
	203
	204	if (slab_is_available()) {
	205	p = pud_alloc(&init_mm, p4d, addr);
	206	if (!p)
	207	return -ENOMEM;
	208	} else {
	209	p4d_populate(&init_mm, p4d,
	210	early_alloc(PAGE_SIZE, NUMA_NO_NODE));
	211	}
c2febafc KS	212	}
	213	zero_pud_populate(p4d, addr, next);
	214	} while (p4d++, addr = next, addr != end);
0207df4f AR	215
0207df4f AR	216	return 0;
c2febafc KS	217	}
c2febafc KS	218
69786cdb	219	/**
9577dd74 AK	220	* kasan_populate_early_shadow - populate shadow memory region with
9577dd74 AK	221	* kasan_early_shadow_page
69786cdb AR	222	* @shadow_start - start of the memory range to populate
	223	* @shadow_end - end of the memory range to populate
	224	*/
9577dd74 AK	225	int __ref kasan_populate_early_shadow(const void *shadow_start,
9577dd74 AK	226	const void *shadow_end)
69786cdb AR	227	{
	228	unsigned long addr = (unsigned long)shadow_start;
	229	unsigned long end = (unsigned long)shadow_end;
	230	pgd_t *pgd = pgd_offset_k(addr);
	231	unsigned long next;
	232
	233	do {
	234	next = pgd_addr_end(addr, end);
	235
	236	if (IS_ALIGNED(addr, PGDIR_SIZE) && end - addr >= PGDIR_SIZE) {
c2febafc	237	p4d_t *p4d;
69786cdb AR	238	pud_t *pud;
	239	pmd_t *pmd;
	240
	241	/*
9577dd74	242	* kasan_early_shadow_pud should be populated with pmds
69786cdb AR	243	* at this moment.
	244	* [pud,pmd]_populate*() below needed only for
	245	* 3,2 - level page tables where we don't have
	246	* puds,pmds, so pgd_populate(), pud_populate()
	247	* is noops.
	248	*/
9577dd74 AK	249	pgd_populate(&init_mm, pgd,
9577dd74 AK	250	lm_alias(kasan_early_shadow_p4d));
c2febafc	251	p4d = p4d_offset(pgd, addr);
9577dd74 AK	252	p4d_populate(&init_mm, p4d,
9577dd74 AK	253	lm_alias(kasan_early_shadow_pud));
c2febafc	254	pud = pud_offset(p4d, addr);
9577dd74 AK	255	pud_populate(&init_mm, pud,
9577dd74 AK	256	lm_alias(kasan_early_shadow_pmd));
69786cdb	257	pmd = pmd_offset(pud, addr);
9577dd74 AK	258	pmd_populate_kernel(&init_mm, pmd,
9577dd74 AK	259	lm_alias(kasan_early_shadow_pte));
69786cdb AR	260	continue;
	261	}
	262
	263	if (pgd_none(*pgd)) {
0207df4f AR	264	p4d_t *p;
	265
	266	if (slab_is_available()) {
	267	p = p4d_alloc(&init_mm, pgd, addr);
	268	if (!p)
	269	return -ENOMEM;
	270	} else {
	271	pgd_populate(&init_mm, pgd,
	272	early_alloc(PAGE_SIZE, NUMA_NO_NODE));
	273	}
69786cdb	274	}
c2febafc	275	zero_p4d_populate(pgd, addr, next);
69786cdb	276	} while (pgd++, addr = next, addr != end);
0207df4f AR	277
	278	return 0;
	279	}
	280
	281	static void kasan_free_pte(pte_t pte_start, pmd_t pmd)
	282	{
	283	pte_t *pte;
	284	int i;
	285
	286	for (i = 0; i < PTRS_PER_PTE; i++) {
	287	pte = pte_start + i;
	288	if (!pte_none(*pte))
	289	return;
	290	}
	291
	292	pte_free_kernel(&init_mm, (pte_t )page_to_virt(pmd_page(pmd)));
	293	pmd_clear(pmd);
	294	}
	295
	296	static void kasan_free_pmd(pmd_t pmd_start, pud_t pud)
	297	{
	298	pmd_t *pmd;
	299	int i;
	300
	301	for (i = 0; i < PTRS_PER_PMD; i++) {
	302	pmd = pmd_start + i;
	303	if (!pmd_none(*pmd))
	304	return;
	305	}
	306
	307	pmd_free(&init_mm, (pmd_t )page_to_virt(pud_page(pud)));
	308	pud_clear(pud);
	309	}
	310
	311	static void kasan_free_pud(pud_t pud_start, p4d_t p4d)
	312	{
	313	pud_t *pud;
	314	int i;
	315
	316	for (i = 0; i < PTRS_PER_PUD; i++) {
	317	pud = pud_start + i;
	318	if (!pud_none(*pud))
	319	return;
	320	}
	321
	322	pud_free(&init_mm, (pud_t )page_to_virt(p4d_page(p4d)));
	323	p4d_clear(p4d);
	324	}
	325
	326	static void kasan_free_p4d(p4d_t p4d_start, pgd_t pgd)
	327	{
	328	p4d_t *p4d;
	329	int i;
	330
	331	for (i = 0; i < PTRS_PER_P4D; i++) {
	332	p4d = p4d_start + i;
	333	if (!p4d_none(*p4d))
	334	return;
	335	}
	336
	337	p4d_free(&init_mm, (p4d_t )page_to_virt(pgd_page(pgd)));
	338	pgd_clear(pgd);
	339	}
	340
341	static void kasan_remove_pte_table(pte_t *pte, unsigned long addr,
342	unsigned long end)
343	{
344	unsigned long next;
345
346	for (; addr < end; addr = next, pte++) {
347	next = (addr + PAGE_SIZE) & PAGE_MASK;
348	if (next > end)
349	next = end;
350
351	if (!pte_present(*pte))
352	continue;
353
9577dd74	354	if (WARN_ON(!kasan_early_shadow_page_entry(*pte)))
0207df4f AR	355	continue;
	356	pte_clear(&init_mm, addr, pte);
	357	}
	358	}
	359
	360	static void kasan_remove_pmd_table(pmd_t *pmd, unsigned long addr,
	361	unsigned long end)
	362	{
	363	unsigned long next;
	364
	365	for (; addr < end; addr = next, pmd++) {
	366	pte_t *pte;
	367
	368	next = pmd_addr_end(addr, end);
	369
	370	if (!pmd_present(*pmd))
	371	continue;
	372
	373	if (kasan_pte_table(*pmd)) {
	374	if (IS_ALIGNED(addr, PMD_SIZE) &&
	375	IS_ALIGNED(next, PMD_SIZE))
	376	pmd_clear(pmd);
	377	continue;
	378	}
	379	pte = pte_offset_kernel(pmd, addr);
	380	kasan_remove_pte_table(pte, addr, next);
	381	kasan_free_pte(pte_offset_kernel(pmd, 0), pmd);
	382	}
	383	}
	384
	385	static void kasan_remove_pud_table(pud_t *pud, unsigned long addr,
	386	unsigned long end)
	387	{
	388	unsigned long next;
	389
	390	for (; addr < end; addr = next, pud++) {
	391	pmd_t pmd, pmd_base;
	392
	393	next = pud_addr_end(addr, end);
	394
	395	if (!pud_present(*pud))
	396	continue;
	397
	398	if (kasan_pmd_table(*pud)) {
	399	if (IS_ALIGNED(addr, PUD_SIZE) &&
	400	IS_ALIGNED(next, PUD_SIZE))
	401	pud_clear(pud);
	402	continue;
	403	}
	404	pmd = pmd_offset(pud, addr);
	405	pmd_base = pmd_offset(pud, 0);
	406	kasan_remove_pmd_table(pmd, addr, next);
	407	kasan_free_pmd(pmd_base, pud);
	408	}
	409	}
	410
	411	static void kasan_remove_p4d_table(p4d_t *p4d, unsigned long addr,
	412	unsigned long end)
	413	{
	414	unsigned long next;
	415
	416	for (; addr < end; addr = next, p4d++) {
	417	pud_t *pud;
	418
419	next = p4d_addr_end(addr, end);
420
421	if (!p4d_present(*p4d))
422	continue;
423
424	if (kasan_pud_table(*p4d)) {
425	if (IS_ALIGNED(addr, P4D_SIZE) &&
426	IS_ALIGNED(next, P4D_SIZE))
427	p4d_clear(p4d);
428	continue;
429	}
430	pud = pud_offset(p4d, addr);
431	kasan_remove_pud_table(pud, addr, next);
432	kasan_free_pud(pud_offset(p4d, 0), p4d);
433	}
434	}
435
436	void kasan_remove_zero_shadow(void *start, unsigned long size)
437	{
438	unsigned long addr, end, next;
439	pgd_t *pgd;
440
441	addr = (unsigned long)kasan_mem_to_shadow(start);
442	end = addr + (size >> KASAN_SHADOW_SCALE_SHIFT);
443
affc3f07 AK	444	if (WARN_ON((unsigned long)start % KASAN_MEMORY_PER_SHADOW_PAGE) \|\|
affc3f07 AK	445	WARN_ON(size % KASAN_MEMORY_PER_SHADOW_PAGE))
0207df4f AR	446	return;
	447
	448	for (; addr < end; addr = next) {
	449	p4d_t *p4d;
	450
	451	next = pgd_addr_end(addr, end);
	452
	453	pgd = pgd_offset_k(addr);
	454	if (!pgd_present(*pgd))
	455	continue;
	456
	457	if (kasan_p4d_table(*pgd)) {
	458	if (IS_ALIGNED(addr, PGDIR_SIZE) &&
	459	IS_ALIGNED(next, PGDIR_SIZE))
	460	pgd_clear(pgd);
	461	continue;
	462	}
	463
	464	p4d = p4d_offset(pgd, addr);
	465	kasan_remove_p4d_table(p4d, addr, next);
	466	kasan_free_p4d(p4d_offset(pgd, 0), pgd);
	467	}
	468	}
	469
	470	int kasan_add_zero_shadow(void *start, unsigned long size)
	471	{
	472	int ret;
	473	void shadow_start, shadow_end;
	474
	475	shadow_start = kasan_mem_to_shadow(start);
	476	shadow_end = shadow_start + (size >> KASAN_SHADOW_SCALE_SHIFT);
	477
affc3f07 AK	478	if (WARN_ON((unsigned long)start % KASAN_MEMORY_PER_SHADOW_PAGE) \|\|
affc3f07 AK	479	WARN_ON(size % KASAN_MEMORY_PER_SHADOW_PAGE))
0207df4f AR	480	return -EINVAL;
0207df4f AR	481
9577dd74	482	ret = kasan_populate_early_shadow(shadow_start, shadow_end);
0207df4f AR	483	if (ret)
	484	kasan_remove_zero_shadow(shadow_start,
	485	size >> KASAN_SHADOW_SCALE_SHIFT);
	486	return ret;
69786cdb	487	}