[linux-block.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 0;
}
#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 0;
}
#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 0;
}
#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)
{
	return memblock_alloc_try_nid(size, size, __pa(MAX_DMA_ADDRESS),
					MEMBLOCK_ALLOC_ACCESSIBLE, node);
}

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	{
	45	return 0;
	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	{
	57	return 0;
	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	{
	69	return 0;
	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	{
eb31d559	86	return memblock_alloc_try_nid(size, size, __pa(MAX_DMA_ADDRESS),
97ad1087	87	MEMBLOCK_ALLOC_ACCESSIBLE, node);
69786cdb AR	88	}
69786cdb AR	89
0207df4f	90	static void __ref zero_pte_populate(pmd_t *pmd, unsigned long addr,
69786cdb AR	91	unsigned long end)
	92	{
	93	pte_t *pte = pte_offset_kernel(pmd, addr);
	94	pte_t zero_pte;
	95
9577dd74 AK	96	zero_pte = pfn_pte(PFN_DOWN(__pa_symbol(kasan_early_shadow_page)),
9577dd74 AK	97	PAGE_KERNEL);
69786cdb AR	98	zero_pte = pte_wrprotect(zero_pte);
	99
	100	while (addr + PAGE_SIZE <= end) {
	101	set_pte_at(&init_mm, addr, pte, zero_pte);
	102	addr += PAGE_SIZE;
	103	pte = pte_offset_kernel(pmd, addr);
	104	}
	105	}
	106
0207df4f	107	static int __ref zero_pmd_populate(pud_t *pud, unsigned long addr,
69786cdb AR	108	unsigned long end)
	109	{
	110	pmd_t *pmd = pmd_offset(pud, addr);
	111	unsigned long next;
	112
	113	do {
	114	next = pmd_addr_end(addr, end);
	115
	116	if (IS_ALIGNED(addr, PMD_SIZE) && end - addr >= PMD_SIZE) {
9577dd74 AK	117	pmd_populate_kernel(&init_mm, pmd,
9577dd74 AK	118	lm_alias(kasan_early_shadow_pte));
69786cdb AR	119	continue;
	120	}
	121
	122	if (pmd_none(*pmd)) {
0207df4f AR	123	pte_t *p;
	124
	125	if (slab_is_available())
4cf58924	126	p = pte_alloc_one_kernel(&init_mm);
0207df4f AR	127	else
	128	p = early_alloc(PAGE_SIZE, NUMA_NO_NODE);
	129	if (!p)
	130	return -ENOMEM;
	131
	132	pmd_populate_kernel(&init_mm, pmd, p);
69786cdb AR	133	}
	134	zero_pte_populate(pmd, addr, next);
	135	} while (pmd++, addr = next, addr != end);
0207df4f AR	136
0207df4f AR	137	return 0;
69786cdb AR	138	}
69786cdb AR	139
0207df4f	140	static int __ref zero_pud_populate(p4d_t *p4d, unsigned long addr,
69786cdb AR	141	unsigned long end)
69786cdb AR	142	{
c2febafc	143	pud_t *pud = pud_offset(p4d, addr);
69786cdb AR	144	unsigned long next;
	145
	146	do {
	147	next = pud_addr_end(addr, end);
	148	if (IS_ALIGNED(addr, PUD_SIZE) && end - addr >= PUD_SIZE) {
	149	pmd_t *pmd;
	150
9577dd74 AK	151	pud_populate(&init_mm, pud,
9577dd74 AK	152	lm_alias(kasan_early_shadow_pmd));
69786cdb	153	pmd = pmd_offset(pud, addr);
9577dd74 AK	154	pmd_populate_kernel(&init_mm, pmd,
9577dd74 AK	155	lm_alias(kasan_early_shadow_pte));
69786cdb AR	156	continue;
	157	}
	158
	159	if (pud_none(*pud)) {
0207df4f AR	160	pmd_t *p;
	161
	162	if (slab_is_available()) {
	163	p = pmd_alloc(&init_mm, pud, addr);
	164	if (!p)
	165	return -ENOMEM;
	166	} else {
	167	pud_populate(&init_mm, pud,
	168	early_alloc(PAGE_SIZE, NUMA_NO_NODE));
	169	}
69786cdb AR	170	}
	171	zero_pmd_populate(pud, addr, next);
	172	} while (pud++, addr = next, addr != end);
0207df4f AR	173
0207df4f AR	174	return 0;
69786cdb AR	175	}
69786cdb AR	176
0207df4f	177	static int __ref zero_p4d_populate(pgd_t *pgd, unsigned long addr,
c2febafc KS	178	unsigned long end)
	179	{
	180	p4d_t *p4d = p4d_offset(pgd, addr);
	181	unsigned long next;
	182
	183	do {
	184	next = p4d_addr_end(addr, end);
458f7920 JK	185	if (IS_ALIGNED(addr, P4D_SIZE) && end - addr >= P4D_SIZE) {
	186	pud_t *pud;
	187	pmd_t *pmd;
	188
9577dd74 AK	189	p4d_populate(&init_mm, p4d,
9577dd74 AK	190	lm_alias(kasan_early_shadow_pud));
458f7920	191	pud = pud_offset(p4d, addr);
9577dd74 AK	192	pud_populate(&init_mm, pud,
9577dd74 AK	193	lm_alias(kasan_early_shadow_pmd));
458f7920 JK	194	pmd = pmd_offset(pud, addr);
458f7920 JK	195	pmd_populate_kernel(&init_mm, pmd,
9577dd74	196	lm_alias(kasan_early_shadow_pte));
458f7920 JK	197	continue;
458f7920 JK	198	}
c2febafc KS	199
c2febafc KS	200	if (p4d_none(*p4d)) {
0207df4f AR	201	pud_t *p;
	202
	203	if (slab_is_available()) {
	204	p = pud_alloc(&init_mm, p4d, addr);
	205	if (!p)
	206	return -ENOMEM;
	207	} else {
	208	p4d_populate(&init_mm, p4d,
	209	early_alloc(PAGE_SIZE, NUMA_NO_NODE));
	210	}
c2febafc KS	211	}
	212	zero_pud_populate(p4d, addr, next);
	213	} while (p4d++, addr = next, addr != end);
0207df4f AR	214
0207df4f AR	215	return 0;
c2febafc KS	216	}
c2febafc KS	217
69786cdb	218	/**
9577dd74 AK	219	* kasan_populate_early_shadow - populate shadow memory region with
9577dd74 AK	220	* kasan_early_shadow_page
69786cdb AR	221	* @shadow_start - start of the memory range to populate
	222	* @shadow_end - end of the memory range to populate
	223	*/
9577dd74 AK	224	int __ref kasan_populate_early_shadow(const void *shadow_start,
9577dd74 AK	225	const void *shadow_end)
69786cdb AR	226	{
	227	unsigned long addr = (unsigned long)shadow_start;
	228	unsigned long end = (unsigned long)shadow_end;
	229	pgd_t *pgd = pgd_offset_k(addr);
	230	unsigned long next;
	231
	232	do {
	233	next = pgd_addr_end(addr, end);
	234
	235	if (IS_ALIGNED(addr, PGDIR_SIZE) && end - addr >= PGDIR_SIZE) {
c2febafc	236	p4d_t *p4d;
69786cdb AR	237	pud_t *pud;
	238	pmd_t *pmd;
	239
	240	/*
9577dd74	241	* kasan_early_shadow_pud should be populated with pmds
69786cdb AR	242	* at this moment.
	243	* [pud,pmd]_populate*() below needed only for
	244	* 3,2 - level page tables where we don't have
	245	* puds,pmds, so pgd_populate(), pud_populate()
	246	* is noops.
c2febafc KS	247	*
	248	* The ifndef is required to avoid build breakage.
	249	*
	250	* With 5level-fixup.h, pgd_populate() is not nop and
9577dd74	251	* we reference kasan_early_shadow_p4d. It's not defined
c2febafc KS	252	* unless 5-level paging enabled.
	253	*
	254	* The ifndef can be dropped once all KASAN-enabled
	255	* architectures will switch to pgtable-nop4d.h.
69786cdb	256	*/
c2febafc	257	#ifndef __ARCH_HAS_5LEVEL_HACK
9577dd74 AK	258	pgd_populate(&init_mm, pgd,
9577dd74 AK	259	lm_alias(kasan_early_shadow_p4d));
c2febafc KS	260	#endif
c2febafc KS	261	p4d = p4d_offset(pgd, addr);
9577dd74 AK	262	p4d_populate(&init_mm, p4d,
9577dd74 AK	263	lm_alias(kasan_early_shadow_pud));
c2febafc	264	pud = pud_offset(p4d, addr);
9577dd74 AK	265	pud_populate(&init_mm, pud,
9577dd74 AK	266	lm_alias(kasan_early_shadow_pmd));
69786cdb	267	pmd = pmd_offset(pud, addr);
9577dd74 AK	268	pmd_populate_kernel(&init_mm, pmd,
9577dd74 AK	269	lm_alias(kasan_early_shadow_pte));
69786cdb AR	270	continue;
	271	}
	272
	273	if (pgd_none(*pgd)) {
0207df4f AR	274	p4d_t *p;
	275
	276	if (slab_is_available()) {
	277	p = p4d_alloc(&init_mm, pgd, addr);
	278	if (!p)
	279	return -ENOMEM;
	280	} else {
	281	pgd_populate(&init_mm, pgd,
	282	early_alloc(PAGE_SIZE, NUMA_NO_NODE));
	283	}
69786cdb	284	}
c2febafc	285	zero_p4d_populate(pgd, addr, next);
69786cdb	286	} while (pgd++, addr = next, addr != end);
0207df4f AR	287
	288	return 0;
	289	}
	290
	291	static void kasan_free_pte(pte_t pte_start, pmd_t pmd)
	292	{
	293	pte_t *pte;
	294	int i;
	295
	296	for (i = 0; i < PTRS_PER_PTE; i++) {
	297	pte = pte_start + i;
	298	if (!pte_none(*pte))
	299	return;
	300	}
	301
	302	pte_free_kernel(&init_mm, (pte_t )page_to_virt(pmd_page(pmd)));
	303	pmd_clear(pmd);
	304	}
	305
	306	static void kasan_free_pmd(pmd_t pmd_start, pud_t pud)
	307	{
	308	pmd_t *pmd;
	309	int i;
	310
	311	for (i = 0; i < PTRS_PER_PMD; i++) {
	312	pmd = pmd_start + i;
	313	if (!pmd_none(*pmd))
	314	return;
	315	}
	316
	317	pmd_free(&init_mm, (pmd_t )page_to_virt(pud_page(pud)));
	318	pud_clear(pud);
	319	}
	320
	321	static void kasan_free_pud(pud_t pud_start, p4d_t p4d)
	322	{
	323	pud_t *pud;
	324	int i;
	325
	326	for (i = 0; i < PTRS_PER_PUD; i++) {
	327	pud = pud_start + i;
	328	if (!pud_none(*pud))
	329	return;
	330	}
	331
	332	pud_free(&init_mm, (pud_t )page_to_virt(p4d_page(p4d)));
	333	p4d_clear(p4d);
	334	}
	335
	336	static void kasan_free_p4d(p4d_t p4d_start, pgd_t pgd)
	337	{
	338	p4d_t *p4d;
	339	int i;
	340
	341	for (i = 0; i < PTRS_PER_P4D; i++) {
	342	p4d = p4d_start + i;
	343	if (!p4d_none(*p4d))
	344	return;
	345	}
	346
	347	p4d_free(&init_mm, (p4d_t )page_to_virt(pgd_page(pgd)));
	348	pgd_clear(pgd);
	349	}
	350
351	static void kasan_remove_pte_table(pte_t *pte, unsigned long addr,
352	unsigned long end)
353	{
354	unsigned long next;
355
356	for (; addr < end; addr = next, pte++) {
357	next = (addr + PAGE_SIZE) & PAGE_MASK;
358	if (next > end)
359	next = end;
360
361	if (!pte_present(*pte))
362	continue;
363
9577dd74	364	if (WARN_ON(!kasan_early_shadow_page_entry(*pte)))
0207df4f AR	365	continue;
	366	pte_clear(&init_mm, addr, pte);
	367	}
	368	}
	369
	370	static void kasan_remove_pmd_table(pmd_t *pmd, unsigned long addr,
	371	unsigned long end)
	372	{
	373	unsigned long next;
	374
	375	for (; addr < end; addr = next, pmd++) {
	376	pte_t *pte;
	377
	378	next = pmd_addr_end(addr, end);
	379
	380	if (!pmd_present(*pmd))
	381	continue;
	382
	383	if (kasan_pte_table(*pmd)) {
	384	if (IS_ALIGNED(addr, PMD_SIZE) &&
	385	IS_ALIGNED(next, PMD_SIZE))
	386	pmd_clear(pmd);
	387	continue;
	388	}
	389	pte = pte_offset_kernel(pmd, addr);
	390	kasan_remove_pte_table(pte, addr, next);
	391	kasan_free_pte(pte_offset_kernel(pmd, 0), pmd);
	392	}
	393	}
	394
	395	static void kasan_remove_pud_table(pud_t *pud, unsigned long addr,
	396	unsigned long end)
	397	{
	398	unsigned long next;
	399
	400	for (; addr < end; addr = next, pud++) {
	401	pmd_t pmd, pmd_base;
	402
	403	next = pud_addr_end(addr, end);
	404
	405	if (!pud_present(*pud))
	406	continue;
	407
	408	if (kasan_pmd_table(*pud)) {
	409	if (IS_ALIGNED(addr, PUD_SIZE) &&
	410	IS_ALIGNED(next, PUD_SIZE))
	411	pud_clear(pud);
	412	continue;
	413	}
	414	pmd = pmd_offset(pud, addr);
	415	pmd_base = pmd_offset(pud, 0);
	416	kasan_remove_pmd_table(pmd, addr, next);
	417	kasan_free_pmd(pmd_base, pud);
	418	}
	419	}
	420
	421	static void kasan_remove_p4d_table(p4d_t *p4d, unsigned long addr,
	422	unsigned long end)
	423	{
	424	unsigned long next;
	425
	426	for (; addr < end; addr = next, p4d++) {
	427	pud_t *pud;
	428
429	next = p4d_addr_end(addr, end);
430
431	if (!p4d_present(*p4d))
432	continue;
433
434	if (kasan_pud_table(*p4d)) {
435	if (IS_ALIGNED(addr, P4D_SIZE) &&
436	IS_ALIGNED(next, P4D_SIZE))
437	p4d_clear(p4d);
438	continue;
439	}
440	pud = pud_offset(p4d, addr);
441	kasan_remove_pud_table(pud, addr, next);
442	kasan_free_pud(pud_offset(p4d, 0), p4d);
443	}
444	}
445
446	void kasan_remove_zero_shadow(void *start, unsigned long size)
447	{
448	unsigned long addr, end, next;
449	pgd_t *pgd;
450
451	addr = (unsigned long)kasan_mem_to_shadow(start);
452	end = addr + (size >> KASAN_SHADOW_SCALE_SHIFT);
453
454	if (WARN_ON((unsigned long)start %
455	(KASAN_SHADOW_SCALE_SIZE * PAGE_SIZE)) \|\|
456	WARN_ON(size % (KASAN_SHADOW_SCALE_SIZE * PAGE_SIZE)))
457	return;
458
459	for (; addr < end; addr = next) {
460	p4d_t *p4d;
461
462	next = pgd_addr_end(addr, end);
463
464	pgd = pgd_offset_k(addr);
465	if (!pgd_present(*pgd))
466	continue;
467
468	if (kasan_p4d_table(*pgd)) {
469	if (IS_ALIGNED(addr, PGDIR_SIZE) &&
470	IS_ALIGNED(next, PGDIR_SIZE))
471	pgd_clear(pgd);
472	continue;
473	}
474
475	p4d = p4d_offset(pgd, addr);
476	kasan_remove_p4d_table(p4d, addr, next);
477	kasan_free_p4d(p4d_offset(pgd, 0), pgd);
478	}
479	}
480
481	int kasan_add_zero_shadow(void *start, unsigned long size)
482	{
483	int ret;
484	void shadow_start, shadow_end;
485
486	shadow_start = kasan_mem_to_shadow(start);
487	shadow_end = shadow_start + (size >> KASAN_SHADOW_SCALE_SHIFT);
488
489	if (WARN_ON((unsigned long)start %
490	(KASAN_SHADOW_SCALE_SIZE * PAGE_SIZE)) \|\|
491	WARN_ON(size % (KASAN_SHADOW_SCALE_SIZE * PAGE_SIZE)))
492	return -EINVAL;
493
9577dd74	494	ret = kasan_populate_early_shadow(shadow_start, shadow_end);
0207df4f AR	495	if (ret)
	496	kasan_remove_zero_shadow(shadow_start,
	497	size >> KASAN_SHADOW_SCALE_SHIFT);
	498	return ret;
69786cdb	499	}