[linux-block.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[MAX_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[MAX_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[MAX_PTRS_PER_PTE + PTE_HWTABLE_PTRS]
	__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(start, size);
	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
cb32c9c5	44	pud_t kasan_early_shadow_pud[MAX_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
cb32c9c5	56	pmd_t kasan_early_shadow_pmd[MAX_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
cb32c9c5	67	pte_t kasan_early_shadow_pte[MAX_PTRS_PER_PTE + PTE_HWTABLE_PTRS]
29970dc2	68	__page_aligned_bss;
69786cdb	69
0207df4f AR	70	static inline bool kasan_pte_table(pmd_t pmd)
0207df4f AR	71	{
9577dd74	72	return pmd_page(pmd) == virt_to_page(lm_alias(kasan_early_shadow_pte));
0207df4f AR	73	}
0207df4f AR	74
9577dd74	75	static inline bool kasan_early_shadow_page_entry(pte_t pte)
0207df4f	76	{
9577dd74	77	return pte_page(pte) == virt_to_page(lm_alias(kasan_early_shadow_page));
0207df4f AR	78	}
0207df4f AR	79
69786cdb AR	80	static __init void *early_alloc(size_t size, int node)
69786cdb AR	81	{
8a7f97b9 MR	82	void *ptr = memblock_alloc_try_nid(size, size, __pa(MAX_DMA_ADDRESS),
	83	MEMBLOCK_ALLOC_ACCESSIBLE, node);
	84
	85	if (!ptr)
	86	panic("%s: Failed to allocate %zu bytes align=%zx nid=%d from=%llx\n",
	87	__func__, size, size, node, (u64)__pa(MAX_DMA_ADDRESS));
	88
	89	return ptr;
69786cdb AR	90	}
69786cdb AR	91
0207df4f	92	static void __ref zero_pte_populate(pmd_t *pmd, unsigned long addr,
69786cdb AR	93	unsigned long end)
	94	{
	95	pte_t *pte = pte_offset_kernel(pmd, addr);
	96	pte_t zero_pte;
	97
9577dd74 AK	98	zero_pte = pfn_pte(PFN_DOWN(__pa_symbol(kasan_early_shadow_page)),
9577dd74 AK	99	PAGE_KERNEL);
69786cdb AR	100	zero_pte = pte_wrprotect(zero_pte);
	101
	102	while (addr + PAGE_SIZE <= end) {
	103	set_pte_at(&init_mm, addr, pte, zero_pte);
	104	addr += PAGE_SIZE;
	105	pte = pte_offset_kernel(pmd, addr);
	106	}
	107	}
	108
0207df4f	109	static int __ref zero_pmd_populate(pud_t *pud, unsigned long addr,
69786cdb AR	110	unsigned long end)
	111	{
	112	pmd_t *pmd = pmd_offset(pud, addr);
	113	unsigned long next;
	114
	115	do {
	116	next = pmd_addr_end(addr, end);
	117
	118	if (IS_ALIGNED(addr, PMD_SIZE) && end - addr >= PMD_SIZE) {
9577dd74 AK	119	pmd_populate_kernel(&init_mm, pmd,
9577dd74 AK	120	lm_alias(kasan_early_shadow_pte));
69786cdb AR	121	continue;
	122	}
	123
	124	if (pmd_none(*pmd)) {
0207df4f AR	125	pte_t *p;
	126
	127	if (slab_is_available())
4cf58924	128	p = pte_alloc_one_kernel(&init_mm);
0207df4f AR	129	else
	130	p = early_alloc(PAGE_SIZE, NUMA_NO_NODE);
	131	if (!p)
	132	return -ENOMEM;
	133
	134	pmd_populate_kernel(&init_mm, pmd, p);
69786cdb AR	135	}
	136	zero_pte_populate(pmd, addr, next);
	137	} while (pmd++, addr = next, addr != end);
0207df4f AR	138
0207df4f AR	139	return 0;
69786cdb AR	140	}
69786cdb AR	141
0207df4f	142	static int __ref zero_pud_populate(p4d_t *p4d, unsigned long addr,
69786cdb AR	143	unsigned long end)
69786cdb AR	144	{
c2febafc	145	pud_t *pud = pud_offset(p4d, addr);
69786cdb AR	146	unsigned long next;
	147
	148	do {
	149	next = pud_addr_end(addr, end);
	150	if (IS_ALIGNED(addr, PUD_SIZE) && end - addr >= PUD_SIZE) {
	151	pmd_t *pmd;
	152
9577dd74 AK	153	pud_populate(&init_mm, pud,
9577dd74 AK	154	lm_alias(kasan_early_shadow_pmd));
69786cdb	155	pmd = pmd_offset(pud, addr);
9577dd74 AK	156	pmd_populate_kernel(&init_mm, pmd,
9577dd74 AK	157	lm_alias(kasan_early_shadow_pte));
69786cdb AR	158	continue;
	159	}
	160
	161	if (pud_none(*pud)) {
0207df4f AR	162	pmd_t *p;
	163
	164	if (slab_is_available()) {
	165	p = pmd_alloc(&init_mm, pud, addr);
	166	if (!p)
	167	return -ENOMEM;
	168	} else {
	169	pud_populate(&init_mm, pud,
	170	early_alloc(PAGE_SIZE, NUMA_NO_NODE));
	171	}
69786cdb AR	172	}
	173	zero_pmd_populate(pud, addr, next);
	174	} while (pud++, addr = next, addr != end);
0207df4f AR	175
0207df4f AR	176	return 0;
69786cdb AR	177	}
69786cdb AR	178
0207df4f	179	static int __ref zero_p4d_populate(pgd_t *pgd, unsigned long addr,
c2febafc KS	180	unsigned long end)
	181	{
	182	p4d_t *p4d = p4d_offset(pgd, addr);
	183	unsigned long next;
	184
	185	do {
	186	next = p4d_addr_end(addr, end);
458f7920 JK	187	if (IS_ALIGNED(addr, P4D_SIZE) && end - addr >= P4D_SIZE) {
	188	pud_t *pud;
	189	pmd_t *pmd;
	190
9577dd74 AK	191	p4d_populate(&init_mm, p4d,
9577dd74 AK	192	lm_alias(kasan_early_shadow_pud));
458f7920	193	pud = pud_offset(p4d, addr);
9577dd74 AK	194	pud_populate(&init_mm, pud,
9577dd74 AK	195	lm_alias(kasan_early_shadow_pmd));
458f7920 JK	196	pmd = pmd_offset(pud, addr);
458f7920 JK	197	pmd_populate_kernel(&init_mm, pmd,
9577dd74	198	lm_alias(kasan_early_shadow_pte));
458f7920 JK	199	continue;
458f7920 JK	200	}
c2febafc KS	201
c2febafc KS	202	if (p4d_none(*p4d)) {
0207df4f AR	203	pud_t *p;
	204
	205	if (slab_is_available()) {
	206	p = pud_alloc(&init_mm, p4d, addr);
	207	if (!p)
	208	return -ENOMEM;
	209	} else {
	210	p4d_populate(&init_mm, p4d,
	211	early_alloc(PAGE_SIZE, NUMA_NO_NODE));
	212	}
c2febafc KS	213	}
	214	zero_pud_populate(p4d, addr, next);
	215	} while (p4d++, addr = next, addr != end);
0207df4f AR	216
0207df4f AR	217	return 0;
c2febafc KS	218	}
c2febafc KS	219
69786cdb	220	/**
9577dd74 AK	221	* kasan_populate_early_shadow - populate shadow memory region with
9577dd74 AK	222	* kasan_early_shadow_page
7b6889f5 YK	223	* @shadow_start: start of the memory range to populate
7b6889f5 YK	224	* @shadow_end: end of the memory range to populate
69786cdb	225	*/
9577dd74 AK	226	int __ref kasan_populate_early_shadow(const void *shadow_start,
9577dd74 AK	227	const void *shadow_end)
69786cdb AR	228	{
	229	unsigned long addr = (unsigned long)shadow_start;
	230	unsigned long end = (unsigned long)shadow_end;
	231	pgd_t *pgd = pgd_offset_k(addr);
	232	unsigned long next;
	233
	234	do {
	235	next = pgd_addr_end(addr, end);
	236
	237	if (IS_ALIGNED(addr, PGDIR_SIZE) && end - addr >= PGDIR_SIZE) {
c2febafc	238	p4d_t *p4d;
69786cdb AR	239	pud_t *pud;
	240	pmd_t *pmd;
	241
	242	/*
9577dd74	243	* kasan_early_shadow_pud should be populated with pmds
69786cdb AR	244	* at this moment.
	245	* [pud,pmd]_populate*() below needed only for
	246	* 3,2 - level page tables where we don't have
	247	* puds,pmds, so pgd_populate(), pud_populate()
	248	* is noops.
	249	*/
9577dd74 AK	250	pgd_populate(&init_mm, pgd,
9577dd74 AK	251	lm_alias(kasan_early_shadow_p4d));
c2febafc	252	p4d = p4d_offset(pgd, addr);
9577dd74 AK	253	p4d_populate(&init_mm, p4d,
9577dd74 AK	254	lm_alias(kasan_early_shadow_pud));
c2febafc	255	pud = pud_offset(p4d, addr);
9577dd74 AK	256	pud_populate(&init_mm, pud,
9577dd74 AK	257	lm_alias(kasan_early_shadow_pmd));
69786cdb	258	pmd = pmd_offset(pud, addr);
9577dd74 AK	259	pmd_populate_kernel(&init_mm, pmd,
9577dd74 AK	260	lm_alias(kasan_early_shadow_pte));
69786cdb AR	261	continue;
	262	}
	263
	264	if (pgd_none(*pgd)) {
0207df4f AR	265	p4d_t *p;
	266
	267	if (slab_is_available()) {
	268	p = p4d_alloc(&init_mm, pgd, addr);
	269	if (!p)
	270	return -ENOMEM;
	271	} else {
	272	pgd_populate(&init_mm, pgd,
	273	early_alloc(PAGE_SIZE, NUMA_NO_NODE));
	274	}
69786cdb	275	}
c2febafc	276	zero_p4d_populate(pgd, addr, next);
69786cdb	277	} while (pgd++, addr = next, addr != end);
0207df4f AR	278
	279	return 0;
	280	}
	281
	282	static void kasan_free_pte(pte_t pte_start, pmd_t pmd)
	283	{
	284	pte_t *pte;
	285	int i;
	286
	287	for (i = 0; i < PTRS_PER_PTE; i++) {
	288	pte = pte_start + i;
	289	if (!pte_none(*pte))
	290	return;
	291	}
	292
	293	pte_free_kernel(&init_mm, (pte_t )page_to_virt(pmd_page(pmd)));
	294	pmd_clear(pmd);
	295	}
	296
	297	static void kasan_free_pmd(pmd_t pmd_start, pud_t pud)
	298	{
	299	pmd_t *pmd;
	300	int i;
	301
	302	for (i = 0; i < PTRS_PER_PMD; i++) {
	303	pmd = pmd_start + i;
	304	if (!pmd_none(*pmd))
	305	return;
	306	}
	307
	308	pmd_free(&init_mm, (pmd_t )page_to_virt(pud_page(pud)));
	309	pud_clear(pud);
	310	}
	311
	312	static void kasan_free_pud(pud_t pud_start, p4d_t p4d)
	313	{
	314	pud_t *pud;
	315	int i;
	316
	317	for (i = 0; i < PTRS_PER_PUD; i++) {
	318	pud = pud_start + i;
	319	if (!pud_none(*pud))
	320	return;
	321	}
	322
	323	pud_free(&init_mm, (pud_t )page_to_virt(p4d_page(p4d)));
	324	p4d_clear(p4d);
	325	}
	326
	327	static void kasan_free_p4d(p4d_t p4d_start, pgd_t pgd)
	328	{
	329	p4d_t *p4d;
	330	int i;
	331
	332	for (i = 0; i < PTRS_PER_P4D; i++) {
	333	p4d = p4d_start + i;
	334	if (!p4d_none(*p4d))
	335	return;
	336	}
	337
	338	p4d_free(&init_mm, (p4d_t )page_to_virt(pgd_page(pgd)));
	339	pgd_clear(pgd);
	340	}
	341
342	static void kasan_remove_pte_table(pte_t *pte, unsigned long addr,
343	unsigned long end)
344	{
345	unsigned long next;
346
347	for (; addr < end; addr = next, pte++) {
348	next = (addr + PAGE_SIZE) & PAGE_MASK;
349	if (next > end)
350	next = end;
351
352	if (!pte_present(*pte))
353	continue;
354
9577dd74	355	if (WARN_ON(!kasan_early_shadow_page_entry(*pte)))
0207df4f AR	356	continue;
	357	pte_clear(&init_mm, addr, pte);
	358	}
	359	}
	360
	361	static void kasan_remove_pmd_table(pmd_t *pmd, unsigned long addr,
	362	unsigned long end)
	363	{
	364	unsigned long next;
	365
	366	for (; addr < end; addr = next, pmd++) {
	367	pte_t *pte;
	368
	369	next = pmd_addr_end(addr, end);
	370
	371	if (!pmd_present(*pmd))
	372	continue;
	373
	374	if (kasan_pte_table(*pmd)) {
	375	if (IS_ALIGNED(addr, PMD_SIZE) &&
a11a496e	376	IS_ALIGNED(next, PMD_SIZE)) {
0207df4f	377	pmd_clear(pmd);
a11a496e LC	378	continue;
a11a496e LC	379	}
0207df4f AR	380	}
	381	pte = pte_offset_kernel(pmd, addr);
	382	kasan_remove_pte_table(pte, addr, next);
	383	kasan_free_pte(pte_offset_kernel(pmd, 0), pmd);
	384	}
	385	}
	386
	387	static void kasan_remove_pud_table(pud_t *pud, unsigned long addr,
	388	unsigned long end)
	389	{
	390	unsigned long next;
	391
	392	for (; addr < end; addr = next, pud++) {
	393	pmd_t pmd, pmd_base;
	394
	395	next = pud_addr_end(addr, end);
	396
	397	if (!pud_present(*pud))
	398	continue;
	399
	400	if (kasan_pmd_table(*pud)) {
	401	if (IS_ALIGNED(addr, PUD_SIZE) &&
a11a496e	402	IS_ALIGNED(next, PUD_SIZE)) {
0207df4f	403	pud_clear(pud);
a11a496e LC	404	continue;
a11a496e LC	405	}
0207df4f AR	406	}
	407	pmd = pmd_offset(pud, addr);
	408	pmd_base = pmd_offset(pud, 0);
	409	kasan_remove_pmd_table(pmd, addr, next);
	410	kasan_free_pmd(pmd_base, pud);
	411	}
	412	}
	413
	414	static void kasan_remove_p4d_table(p4d_t *p4d, unsigned long addr,
	415	unsigned long end)
	416	{
	417	unsigned long next;
	418
	419	for (; addr < end; addr = next, p4d++) {
	420	pud_t *pud;
	421
	422	next = p4d_addr_end(addr, end);
	423
	424	if (!p4d_present(*p4d))
	425	continue;
	426
	427	if (kasan_pud_table(*p4d)) {
	428	if (IS_ALIGNED(addr, P4D_SIZE) &&
a11a496e	429	IS_ALIGNED(next, P4D_SIZE)) {
0207df4f	430	p4d_clear(p4d);
a11a496e LC	431	continue;
a11a496e LC	432	}
0207df4f AR	433	}
	434	pud = pud_offset(p4d, addr);
	435	kasan_remove_pud_table(pud, addr, next);
	436	kasan_free_pud(pud_offset(p4d, 0), p4d);
	437	}
	438	}
	439
	440	void kasan_remove_zero_shadow(void *start, unsigned long size)
	441	{
	442	unsigned long addr, end, next;
	443	pgd_t *pgd;
	444
	445	addr = (unsigned long)kasan_mem_to_shadow(start);
	446	end = addr + (size >> KASAN_SHADOW_SCALE_SHIFT);
	447
affc3f07 AK	448	if (WARN_ON((unsigned long)start % KASAN_MEMORY_PER_SHADOW_PAGE) \|\|
affc3f07 AK	449	WARN_ON(size % KASAN_MEMORY_PER_SHADOW_PAGE))
0207df4f AR	450	return;
	451
	452	for (; addr < end; addr = next) {
	453	p4d_t *p4d;
	454
	455	next = pgd_addr_end(addr, end);
	456
	457	pgd = pgd_offset_k(addr);
	458	if (!pgd_present(*pgd))
	459	continue;
	460
	461	if (kasan_p4d_table(*pgd)) {
	462	if (IS_ALIGNED(addr, PGDIR_SIZE) &&
a11a496e	463	IS_ALIGNED(next, PGDIR_SIZE)) {
0207df4f	464	pgd_clear(pgd);
a11a496e LC	465	continue;
a11a496e LC	466	}
0207df4f AR	467	}
	468
	469	p4d = p4d_offset(pgd, addr);
	470	kasan_remove_p4d_table(p4d, addr, next);
	471	kasan_free_p4d(p4d_offset(pgd, 0), pgd);
	472	}
	473	}
	474
	475	int kasan_add_zero_shadow(void *start, unsigned long size)
	476	{
	477	int ret;
	478	void shadow_start, shadow_end;
	479
	480	shadow_start = kasan_mem_to_shadow(start);
	481	shadow_end = shadow_start + (size >> KASAN_SHADOW_SCALE_SHIFT);
	482
affc3f07 AK	483	if (WARN_ON((unsigned long)start % KASAN_MEMORY_PER_SHADOW_PAGE) \|\|
affc3f07 AK	484	WARN_ON(size % KASAN_MEMORY_PER_SHADOW_PAGE))
0207df4f AR	485	return -EINVAL;
0207df4f AR	486
9577dd74	487	ret = kasan_populate_early_shadow(shadow_start, shadow_end);
0207df4f	488	if (ret)
5dabd171	489	kasan_remove_zero_shadow(start, size);
0207df4f	490	return ret;
69786cdb	491	}