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

// SPDX-License-Identifier: GPL-2.0
/*
 * This file contains some kasan initialization code.
 *
 * Copyright (c) 2015 Samsung Electronics Co., Ltd.
 * Author: Andrey Ryabinin <ryabinin.a.a@gmail.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 */

#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.
			 *
			 * The ifndef is required to avoid build breakage.
			 *
			 * With 5level-fixup.h, pgd_populate() is not nop and
			 * we reference kasan_early_shadow_p4d. It's not defined
			 * unless 5-level paging enabled.
			 *
			 * The ifndef can be dropped once all KASAN-enabled
			 * architectures will switch to pgtable-nop4d.h.
			 */
#ifndef __ARCH_HAS_5LEVEL_HACK
			pgd_populate(&init_mm, pgd,
					lm_alias(kasan_early_shadow_p4d));
#endif
			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_SHADOW_SCALE_SIZE * PAGE_SIZE)) ||
	    WARN_ON(size % (KASAN_SHADOW_SCALE_SIZE * PAGE_SIZE)))
		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_SHADOW_SCALE_SIZE * PAGE_SIZE)) ||
	    WARN_ON(size % (KASAN_SHADOW_SCALE_SIZE * PAGE_SIZE)))
		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 AR	2	/*
	3	* This file contains some kasan initialization code.
	4	*
	5	* Copyright (c) 2015 Samsung Electronics Co., Ltd.
	6	* Author: Andrey Ryabinin <ryabinin.a.a@gmail.com>
	7	*
	8	* This program is free software; you can redistribute it and/or modify
	9	* it under the terms of the GNU General Public License version 2 as
	10	* published by the Free Software Foundation.
	11	*
	12	*/
	13
57c8a661	14	#include <linux/memblock.h>
69786cdb AR	15	#include <linux/init.h>
	16	#include <linux/kasan.h>
	17	#include <linux/kernel.h>
5c6a84a3	18	#include <linux/mm.h>
69786cdb	19	#include <linux/pfn.h>
0207df4f	20	#include <linux/slab.h>
69786cdb AR	21
	22	#include <asm/page.h>
	23	#include <asm/pgalloc.h>
	24
0207df4f AR	25	#include "kasan.h"
0207df4f AR	26
69786cdb AR	27	/*
	28	* This page serves two purposes:
	29	* - It used as early shadow memory. The entire shadow region populated
	30	* with this page, before we will be able to setup normal shadow memory.
	31	* - Latter it reused it as zero shadow to cover large ranges of memory
	32	* that allowed to access, but not handled by kasan (vmalloc/vmemmap ...).
	33	*/
9577dd74	34	unsigned char kasan_early_shadow_page[PAGE_SIZE] __page_aligned_bss;
69786cdb	35
c2febafc	36	#if CONFIG_PGTABLE_LEVELS > 4
9577dd74	37	p4d_t kasan_early_shadow_p4d[MAX_PTRS_PER_P4D] __page_aligned_bss;
0207df4f AR	38	static inline bool kasan_p4d_table(pgd_t pgd)
0207df4f AR	39	{
9577dd74	40	return pgd_page(pgd) == virt_to_page(lm_alias(kasan_early_shadow_p4d));
0207df4f AR	41	}
	42	#else
	43	static inline bool kasan_p4d_table(pgd_t pgd)
	44	{
5c0198b6	45	return false;
0207df4f	46	}
c2febafc	47	#endif
69786cdb	48	#if CONFIG_PGTABLE_LEVELS > 3
9577dd74	49	pud_t kasan_early_shadow_pud[PTRS_PER_PUD] __page_aligned_bss;
0207df4f AR	50	static inline bool kasan_pud_table(p4d_t p4d)
0207df4f AR	51	{
9577dd74	52	return p4d_page(p4d) == virt_to_page(lm_alias(kasan_early_shadow_pud));
0207df4f AR	53	}
	54	#else
	55	static inline bool kasan_pud_table(p4d_t p4d)
	56	{
5c0198b6	57	return false;
0207df4f	58	}
69786cdb AR	59	#endif
69786cdb AR	60	#if CONFIG_PGTABLE_LEVELS > 2
9577dd74	61	pmd_t kasan_early_shadow_pmd[PTRS_PER_PMD] __page_aligned_bss;
0207df4f AR	62	static inline bool kasan_pmd_table(pud_t pud)
0207df4f AR	63	{
9577dd74	64	return pud_page(pud) == virt_to_page(lm_alias(kasan_early_shadow_pmd));
0207df4f AR	65	}
	66	#else
	67	static inline bool kasan_pmd_table(pud_t pud)
	68	{
5c0198b6	69	return false;
0207df4f	70	}
69786cdb	71	#endif
9577dd74	72	pte_t kasan_early_shadow_pte[PTRS_PER_PTE] __page_aligned_bss;
69786cdb	73
0207df4f AR	74	static inline bool kasan_pte_table(pmd_t pmd)
0207df4f AR	75	{
9577dd74	76	return pmd_page(pmd) == virt_to_page(lm_alias(kasan_early_shadow_pte));
0207df4f AR	77	}
0207df4f AR	78
9577dd74	79	static inline bool kasan_early_shadow_page_entry(pte_t pte)
0207df4f	80	{
9577dd74	81	return pte_page(pte) == virt_to_page(lm_alias(kasan_early_shadow_page));
0207df4f AR	82	}
0207df4f AR	83
69786cdb AR	84	static __init void *early_alloc(size_t size, int node)
69786cdb AR	85	{
8a7f97b9 MR	86	void *ptr = memblock_alloc_try_nid(size, size, __pa(MAX_DMA_ADDRESS),
	87	MEMBLOCK_ALLOC_ACCESSIBLE, node);
	88
	89	if (!ptr)
	90	panic("%s: Failed to allocate %zu bytes align=%zx nid=%d from=%llx\n",
	91	__func__, size, size, node, (u64)__pa(MAX_DMA_ADDRESS));
	92
	93	return ptr;
69786cdb AR	94	}
69786cdb AR	95
0207df4f	96	static void __ref zero_pte_populate(pmd_t *pmd, unsigned long addr,
69786cdb AR	97	unsigned long end)
	98	{
	99	pte_t *pte = pte_offset_kernel(pmd, addr);
	100	pte_t zero_pte;
	101
9577dd74 AK	102	zero_pte = pfn_pte(PFN_DOWN(__pa_symbol(kasan_early_shadow_page)),
9577dd74 AK	103	PAGE_KERNEL);
69786cdb AR	104	zero_pte = pte_wrprotect(zero_pte);
	105
	106	while (addr + PAGE_SIZE <= end) {
	107	set_pte_at(&init_mm, addr, pte, zero_pte);
	108	addr += PAGE_SIZE;
	109	pte = pte_offset_kernel(pmd, addr);
	110	}
	111	}
	112
0207df4f	113	static int __ref zero_pmd_populate(pud_t *pud, unsigned long addr,
69786cdb AR	114	unsigned long end)
	115	{
	116	pmd_t *pmd = pmd_offset(pud, addr);
	117	unsigned long next;
	118
	119	do {
	120	next = pmd_addr_end(addr, end);
	121
	122	if (IS_ALIGNED(addr, PMD_SIZE) && end - addr >= PMD_SIZE) {
9577dd74 AK	123	pmd_populate_kernel(&init_mm, pmd,
9577dd74 AK	124	lm_alias(kasan_early_shadow_pte));
69786cdb AR	125	continue;
	126	}
	127
	128	if (pmd_none(*pmd)) {
0207df4f AR	129	pte_t *p;
	130
	131	if (slab_is_available())
4cf58924	132	p = pte_alloc_one_kernel(&init_mm);
0207df4f AR	133	else
	134	p = early_alloc(PAGE_SIZE, NUMA_NO_NODE);
	135	if (!p)
	136	return -ENOMEM;
	137
	138	pmd_populate_kernel(&init_mm, pmd, p);
69786cdb AR	139	}
	140	zero_pte_populate(pmd, addr, next);
	141	} while (pmd++, addr = next, addr != end);
0207df4f AR	142
0207df4f AR	143	return 0;
69786cdb AR	144	}
69786cdb AR	145
0207df4f	146	static int __ref zero_pud_populate(p4d_t *p4d, unsigned long addr,
69786cdb AR	147	unsigned long end)
69786cdb AR	148	{
c2febafc	149	pud_t *pud = pud_offset(p4d, addr);
69786cdb AR	150	unsigned long next;
	151
	152	do {
	153	next = pud_addr_end(addr, end);
	154	if (IS_ALIGNED(addr, PUD_SIZE) && end - addr >= PUD_SIZE) {
	155	pmd_t *pmd;
	156
9577dd74 AK	157	pud_populate(&init_mm, pud,
9577dd74 AK	158	lm_alias(kasan_early_shadow_pmd));
69786cdb	159	pmd = pmd_offset(pud, addr);
9577dd74 AK	160	pmd_populate_kernel(&init_mm, pmd,
9577dd74 AK	161	lm_alias(kasan_early_shadow_pte));
69786cdb AR	162	continue;
	163	}
	164
	165	if (pud_none(*pud)) {
0207df4f AR	166	pmd_t *p;
	167
	168	if (slab_is_available()) {
	169	p = pmd_alloc(&init_mm, pud, addr);
	170	if (!p)
	171	return -ENOMEM;
	172	} else {
	173	pud_populate(&init_mm, pud,
	174	early_alloc(PAGE_SIZE, NUMA_NO_NODE));
	175	}
69786cdb AR	176	}
	177	zero_pmd_populate(pud, addr, next);
	178	} while (pud++, addr = next, addr != end);
0207df4f AR	179
0207df4f AR	180	return 0;
69786cdb AR	181	}
69786cdb AR	182
0207df4f	183	static int __ref zero_p4d_populate(pgd_t *pgd, unsigned long addr,
c2febafc KS	184	unsigned long end)
	185	{
	186	p4d_t *p4d = p4d_offset(pgd, addr);
	187	unsigned long next;
	188
	189	do {
	190	next = p4d_addr_end(addr, end);
458f7920 JK	191	if (IS_ALIGNED(addr, P4D_SIZE) && end - addr >= P4D_SIZE) {
	192	pud_t *pud;
	193	pmd_t *pmd;
	194
9577dd74 AK	195	p4d_populate(&init_mm, p4d,
9577dd74 AK	196	lm_alias(kasan_early_shadow_pud));
458f7920	197	pud = pud_offset(p4d, addr);
9577dd74 AK	198	pud_populate(&init_mm, pud,
9577dd74 AK	199	lm_alias(kasan_early_shadow_pmd));
458f7920 JK	200	pmd = pmd_offset(pud, addr);
458f7920 JK	201	pmd_populate_kernel(&init_mm, pmd,
9577dd74	202	lm_alias(kasan_early_shadow_pte));
458f7920 JK	203	continue;
458f7920 JK	204	}
c2febafc KS	205
c2febafc KS	206	if (p4d_none(*p4d)) {
0207df4f AR	207	pud_t *p;
	208
	209	if (slab_is_available()) {
	210	p = pud_alloc(&init_mm, p4d, addr);
	211	if (!p)
	212	return -ENOMEM;
	213	} else {
	214	p4d_populate(&init_mm, p4d,
	215	early_alloc(PAGE_SIZE, NUMA_NO_NODE));
	216	}
c2febafc KS	217	}
	218	zero_pud_populate(p4d, addr, next);
	219	} while (p4d++, addr = next, addr != end);
0207df4f AR	220
0207df4f AR	221	return 0;
c2febafc KS	222	}
c2febafc KS	223
69786cdb	224	/**
9577dd74 AK	225	* kasan_populate_early_shadow - populate shadow memory region with
9577dd74 AK	226	* kasan_early_shadow_page
69786cdb AR	227	* @shadow_start - start of the memory range to populate
	228	* @shadow_end - end of the memory range to populate
	229	*/
9577dd74 AK	230	int __ref kasan_populate_early_shadow(const void *shadow_start,
9577dd74 AK	231	const void *shadow_end)
69786cdb AR	232	{
	233	unsigned long addr = (unsigned long)shadow_start;
	234	unsigned long end = (unsigned long)shadow_end;
	235	pgd_t *pgd = pgd_offset_k(addr);
	236	unsigned long next;
	237
	238	do {
	239	next = pgd_addr_end(addr, end);
	240
	241	if (IS_ALIGNED(addr, PGDIR_SIZE) && end - addr >= PGDIR_SIZE) {
c2febafc	242	p4d_t *p4d;
69786cdb AR	243	pud_t *pud;
	244	pmd_t *pmd;
	245
	246	/*
9577dd74	247	* kasan_early_shadow_pud should be populated with pmds
69786cdb AR	248	* at this moment.
	249	* [pud,pmd]_populate*() below needed only for
	250	* 3,2 - level page tables where we don't have
	251	* puds,pmds, so pgd_populate(), pud_populate()
	252	* is noops.
c2febafc KS	253	*
	254	* The ifndef is required to avoid build breakage.
	255	*
	256	* With 5level-fixup.h, pgd_populate() is not nop and
9577dd74	257	* we reference kasan_early_shadow_p4d. It's not defined
c2febafc KS	258	* unless 5-level paging enabled.
	259	*
	260	* The ifndef can be dropped once all KASAN-enabled
	261	* architectures will switch to pgtable-nop4d.h.
69786cdb	262	*/
c2febafc	263	#ifndef __ARCH_HAS_5LEVEL_HACK
9577dd74 AK	264	pgd_populate(&init_mm, pgd,
9577dd74 AK	265	lm_alias(kasan_early_shadow_p4d));
c2febafc KS	266	#endif
c2febafc KS	267	p4d = p4d_offset(pgd, addr);
9577dd74 AK	268	p4d_populate(&init_mm, p4d,
9577dd74 AK	269	lm_alias(kasan_early_shadow_pud));
c2febafc	270	pud = pud_offset(p4d, addr);
9577dd74 AK	271	pud_populate(&init_mm, pud,
9577dd74 AK	272	lm_alias(kasan_early_shadow_pmd));
69786cdb	273	pmd = pmd_offset(pud, addr);
9577dd74 AK	274	pmd_populate_kernel(&init_mm, pmd,
9577dd74 AK	275	lm_alias(kasan_early_shadow_pte));
69786cdb AR	276	continue;
	277	}
	278
	279	if (pgd_none(*pgd)) {
0207df4f AR	280	p4d_t *p;
	281
	282	if (slab_is_available()) {
	283	p = p4d_alloc(&init_mm, pgd, addr);
	284	if (!p)
	285	return -ENOMEM;
	286	} else {
	287	pgd_populate(&init_mm, pgd,
	288	early_alloc(PAGE_SIZE, NUMA_NO_NODE));
	289	}
69786cdb	290	}
c2febafc	291	zero_p4d_populate(pgd, addr, next);
69786cdb	292	} while (pgd++, addr = next, addr != end);
0207df4f AR	293
	294	return 0;
	295	}
	296
	297	static void kasan_free_pte(pte_t pte_start, pmd_t pmd)
	298	{
	299	pte_t *pte;
	300	int i;
	301
	302	for (i = 0; i < PTRS_PER_PTE; i++) {
	303	pte = pte_start + i;
	304	if (!pte_none(*pte))
	305	return;
	306	}
	307
	308	pte_free_kernel(&init_mm, (pte_t )page_to_virt(pmd_page(pmd)));
	309	pmd_clear(pmd);
	310	}
	311
	312	static void kasan_free_pmd(pmd_t pmd_start, pud_t pud)
	313	{
	314	pmd_t *pmd;
	315	int i;
	316
	317	for (i = 0; i < PTRS_PER_PMD; i++) {
	318	pmd = pmd_start + i;
	319	if (!pmd_none(*pmd))
	320	return;
	321	}
	322
	323	pmd_free(&init_mm, (pmd_t )page_to_virt(pud_page(pud)));
	324	pud_clear(pud);
	325	}
	326
	327	static void kasan_free_pud(pud_t pud_start, p4d_t p4d)
	328	{
	329	pud_t *pud;
	330	int i;
	331
	332	for (i = 0; i < PTRS_PER_PUD; i++) {
	333	pud = pud_start + i;
	334	if (!pud_none(*pud))
	335	return;
	336	}
	337
	338	pud_free(&init_mm, (pud_t )page_to_virt(p4d_page(p4d)));
	339	p4d_clear(p4d);
	340	}
	341
	342	static void kasan_free_p4d(p4d_t p4d_start, pgd_t pgd)
	343	{
	344	p4d_t *p4d;
	345	int i;
	346
	347	for (i = 0; i < PTRS_PER_P4D; i++) {
	348	p4d = p4d_start + i;
	349	if (!p4d_none(*p4d))
	350	return;
	351	}
	352
	353	p4d_free(&init_mm, (p4d_t )page_to_virt(pgd_page(pgd)));
	354	pgd_clear(pgd);
	355	}
	356
357	static void kasan_remove_pte_table(pte_t *pte, unsigned long addr,
358	unsigned long end)
359	{
360	unsigned long next;
361
362	for (; addr < end; addr = next, pte++) {
363	next = (addr + PAGE_SIZE) & PAGE_MASK;
364	if (next > end)
365	next = end;
366
367	if (!pte_present(*pte))
368	continue;
369
9577dd74	370	if (WARN_ON(!kasan_early_shadow_page_entry(*pte)))
0207df4f AR	371	continue;
	372	pte_clear(&init_mm, addr, pte);
	373	}
	374	}
	375
	376	static void kasan_remove_pmd_table(pmd_t *pmd, unsigned long addr,
	377	unsigned long end)
	378	{
	379	unsigned long next;
	380
	381	for (; addr < end; addr = next, pmd++) {
	382	pte_t *pte;
	383
	384	next = pmd_addr_end(addr, end);
	385
	386	if (!pmd_present(*pmd))
	387	continue;
	388
	389	if (kasan_pte_table(*pmd)) {
	390	if (IS_ALIGNED(addr, PMD_SIZE) &&
	391	IS_ALIGNED(next, PMD_SIZE))
	392	pmd_clear(pmd);
	393	continue;
	394	}
	395	pte = pte_offset_kernel(pmd, addr);
	396	kasan_remove_pte_table(pte, addr, next);
	397	kasan_free_pte(pte_offset_kernel(pmd, 0), pmd);
	398	}
	399	}
	400
	401	static void kasan_remove_pud_table(pud_t *pud, unsigned long addr,
	402	unsigned long end)
	403	{
	404	unsigned long next;
	405
	406	for (; addr < end; addr = next, pud++) {
	407	pmd_t pmd, pmd_base;
	408
	409	next = pud_addr_end(addr, end);
	410
	411	if (!pud_present(*pud))
	412	continue;
	413
	414	if (kasan_pmd_table(*pud)) {
	415	if (IS_ALIGNED(addr, PUD_SIZE) &&
	416	IS_ALIGNED(next, PUD_SIZE))
	417	pud_clear(pud);
	418	continue;
	419	}
	420	pmd = pmd_offset(pud, addr);
	421	pmd_base = pmd_offset(pud, 0);
	422	kasan_remove_pmd_table(pmd, addr, next);
	423	kasan_free_pmd(pmd_base, pud);
	424	}
	425	}
	426
	427	static void kasan_remove_p4d_table(p4d_t *p4d, unsigned long addr,
	428	unsigned long end)
	429	{
	430	unsigned long next;
	431
	432	for (; addr < end; addr = next, p4d++) {
	433	pud_t *pud;
	434
435	next = p4d_addr_end(addr, end);
436
437	if (!p4d_present(*p4d))
438	continue;
439
440	if (kasan_pud_table(*p4d)) {
441	if (IS_ALIGNED(addr, P4D_SIZE) &&
442	IS_ALIGNED(next, P4D_SIZE))
443	p4d_clear(p4d);
444	continue;
445	}
446	pud = pud_offset(p4d, addr);
447	kasan_remove_pud_table(pud, addr, next);
448	kasan_free_pud(pud_offset(p4d, 0), p4d);
449	}
450	}
451
452	void kasan_remove_zero_shadow(void *start, unsigned long size)
453	{
454	unsigned long addr, end, next;
455	pgd_t *pgd;
456
457	addr = (unsigned long)kasan_mem_to_shadow(start);
458	end = addr + (size >> KASAN_SHADOW_SCALE_SHIFT);
459
460	if (WARN_ON((unsigned long)start %
461	(KASAN_SHADOW_SCALE_SIZE * PAGE_SIZE)) \|\|
462	WARN_ON(size % (KASAN_SHADOW_SCALE_SIZE * PAGE_SIZE)))
463	return;
464
465	for (; addr < end; addr = next) {
466	p4d_t *p4d;
467
468	next = pgd_addr_end(addr, end);
469
470	pgd = pgd_offset_k(addr);
471	if (!pgd_present(*pgd))
472	continue;
473
474	if (kasan_p4d_table(*pgd)) {
475	if (IS_ALIGNED(addr, PGDIR_SIZE) &&
476	IS_ALIGNED(next, PGDIR_SIZE))
477	pgd_clear(pgd);
478	continue;
479	}
480
481	p4d = p4d_offset(pgd, addr);
482	kasan_remove_p4d_table(p4d, addr, next);
483	kasan_free_p4d(p4d_offset(pgd, 0), pgd);
484	}
485	}
486
487	int kasan_add_zero_shadow(void *start, unsigned long size)
488	{
489	int ret;
490	void shadow_start, shadow_end;
491
492	shadow_start = kasan_mem_to_shadow(start);
493	shadow_end = shadow_start + (size >> KASAN_SHADOW_SCALE_SHIFT);
494
495	if (WARN_ON((unsigned long)start %
496	(KASAN_SHADOW_SCALE_SIZE * PAGE_SIZE)) \|\|
497	WARN_ON(size % (KASAN_SHADOW_SCALE_SIZE * PAGE_SIZE)))
498	return -EINVAL;
499
9577dd74	500	ret = kasan_populate_early_shadow(shadow_start, shadow_end);
0207df4f AR	501	if (ret)
	502	kasan_remove_zero_shadow(shadow_start,
	503	size >> KASAN_SHADOW_SCALE_SHIFT);
	504	return ret;
69786cdb	505	}