arch/arm64/mm/kasan_init.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * This file contains kasan initialization code for ARM64.
  *
  * Copyright (c) 2015 Samsung Electronics Co., Ltd.
  * Author: Andrey Ryabinin <ryabinin.a.a@gmail.com>
  */

 #define pr_fmt(fmt) "kasan: " fmt
 #include <linux/kasan.h>
 #include <linux/kernel.h>
 #include <linux/sched/task.h>
 #include <linux/memblock.h>
 #include <linux/start_kernel.h>
 #include <linux/mm.h>

 #include <asm/mmu_context.h>
 #include <asm/kernel-pgtable.h>
 #include <asm/page.h>
 #include <asm/pgalloc.h>
 #include <asm/sections.h>
 #include <asm/tlbflush.h>

 #if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)

 static pgd_t tmp_pg_dir[PTRS_PER_PGD] __initdata __aligned(PGD_SIZE);

 /*
  * The p*d_populate functions call virt_to_phys implicitly so they can't be used
  * directly on kernel symbols (bm_p*d). All the early functions are called too
  * early to use lm_alias so __p*d_populate functions must be used to populate
  * with the physical address from __pa_symbol.
  */

 static phys_addr_t __init kasan_alloc_zeroed_page(int node)
 {
 	void *p = memblock_alloc_try_nid(PAGE_SIZE, PAGE_SIZE,
 					      __pa(MAX_DMA_ADDRESS),
 					      MEMBLOCK_ALLOC_KASAN, node);
 	if (!p)
 		panic("%s: Failed to allocate %lu bytes align=0x%lx nid=%d from=%llx\n",
 		      __func__, PAGE_SIZE, PAGE_SIZE, node,
 		      __pa(MAX_DMA_ADDRESS));

 	return __pa(p);
 }

 static phys_addr_t __init kasan_alloc_raw_page(int node)
 {
 	void *p = memblock_alloc_try_nid_raw(PAGE_SIZE, PAGE_SIZE,
 						__pa(MAX_DMA_ADDRESS),
 						MEMBLOCK_ALLOC_KASAN, node);
 	if (!p)
 		panic("%s: Failed to allocate %lu bytes align=0x%lx nid=%d from=%llx\n",
 		      __func__, PAGE_SIZE, PAGE_SIZE, node,
 		      __pa(MAX_DMA_ADDRESS));

 	return __pa(p);
 }

 static pte_t *__init kasan_pte_offset(pmd_t *pmdp, unsigned long addr, int node,
 				      bool early)
 {
 	if (pmd_none(READ_ONCE(*pmdp))) {
 		phys_addr_t pte_phys = early ?
 				__pa_symbol(kasan_early_shadow_pte)
 					: kasan_alloc_zeroed_page(node);
 		__pmd_populate(pmdp, pte_phys, PMD_TYPE_TABLE);
 	}

 	return early ? pte_offset_kimg(pmdp, addr)
 		     : pte_offset_kernel(pmdp, addr);
 }

 static pmd_t *__init kasan_pmd_offset(pud_t *pudp, unsigned long addr, int node,
 				      bool early)
 {
 	if (pud_none(READ_ONCE(*pudp))) {
 		phys_addr_t pmd_phys = early ?
 				__pa_symbol(kasan_early_shadow_pmd)
 					: kasan_alloc_zeroed_page(node);
 		__pud_populate(pudp, pmd_phys, PMD_TYPE_TABLE);
 	}

 	return early ? pmd_offset_kimg(pudp, addr) : pmd_offset(pudp, addr);
 }

 static pud_t *__init kasan_pud_offset(p4d_t *p4dp, unsigned long addr, int node,
 				      bool early)
 {
 	if (p4d_none(READ_ONCE(*p4dp))) {
 		phys_addr_t pud_phys = early ?
 				__pa_symbol(kasan_early_shadow_pud)
 					: kasan_alloc_zeroed_page(node);
 		__p4d_populate(p4dp, pud_phys, PMD_TYPE_TABLE);
 	}

 	return early ? pud_offset_kimg(p4dp, addr) : pud_offset(p4dp, addr);
 }

 static void __init kasan_pte_populate(pmd_t *pmdp, unsigned long addr,
 				      unsigned long end, int node, bool early)
 {
 	unsigned long next;
 	pte_t *ptep = kasan_pte_offset(pmdp, addr, node, early);

 	do {
 		phys_addr_t page_phys = early ?
 				__pa_symbol(kasan_early_shadow_page)
 					: kasan_alloc_raw_page(node);
 		if (!early)
 			memset(__va(page_phys), KASAN_SHADOW_INIT, PAGE_SIZE);
 		next = addr + PAGE_SIZE;
 		set_pte(ptep, pfn_pte(__phys_to_pfn(page_phys), PAGE_KERNEL));
 	} while (ptep++, addr = next, addr != end && pte_none(READ_ONCE(*ptep)));
 }

 static void __init kasan_pmd_populate(pud_t *pudp, unsigned long addr,
 				      unsigned long end, int node, bool early)
 {
 	unsigned long next;
 	pmd_t *pmdp = kasan_pmd_offset(pudp, addr, node, early);

 	do {
 		next = pmd_addr_end(addr, end);
 		kasan_pte_populate(pmdp, addr, next, node, early);
 	} while (pmdp++, addr = next, addr != end && pmd_none(READ_ONCE(*pmdp)));
 }

 static void __init kasan_pud_populate(p4d_t *p4dp, unsigned long addr,
 				      unsigned long end, int node, bool early)
 {
 	unsigned long next;
 	pud_t *pudp = kasan_pud_offset(p4dp, addr, node, early);

 	do {
 		next = pud_addr_end(addr, end);
 		kasan_pmd_populate(pudp, addr, next, node, early);
 	} while (pudp++, addr = next, addr != end && pud_none(READ_ONCE(*pudp)));
 }

 static void __init kasan_p4d_populate(pgd_t *pgdp, unsigned long addr,
 				      unsigned long end, int node, bool early)
 {
 	unsigned long next;
 	p4d_t *p4dp = p4d_offset(pgdp, addr);

 	do {
 		next = p4d_addr_end(addr, end);
 		kasan_pud_populate(p4dp, addr, next, node, early);
 	} while (p4dp++, addr = next, addr != end);
 }

 static void __init kasan_pgd_populate(unsigned long addr, unsigned long end,
 				      int node, bool early)
 {
 	unsigned long next;
 	pgd_t *pgdp;

 	pgdp = pgd_offset_k(addr);
 	do {
 		next = pgd_addr_end(addr, end);
 		kasan_p4d_populate(pgdp, addr, next, node, early);
 	} while (pgdp++, addr = next, addr != end);
 }

 /* The early shadow maps everything to a single page of zeroes */
 asmlinkage void __init kasan_early_init(void)
 {
 	BUILD_BUG_ON(KASAN_SHADOW_OFFSET !=
 		KASAN_SHADOW_END - (1UL << (64 - KASAN_SHADOW_SCALE_SHIFT)));
 	BUILD_BUG_ON(!IS_ALIGNED(_KASAN_SHADOW_START(VA_BITS), PGDIR_SIZE));
 	BUILD_BUG_ON(!IS_ALIGNED(_KASAN_SHADOW_START(VA_BITS_MIN), PGDIR_SIZE));
 	BUILD_BUG_ON(!IS_ALIGNED(KASAN_SHADOW_END, PGDIR_SIZE));
 	kasan_pgd_populate(KASAN_SHADOW_START, KASAN_SHADOW_END, NUMA_NO_NODE,
 			   true);
 }

 /* Set up full kasan mappings, ensuring that the mapped pages are zeroed */
 static void __init kasan_map_populate(unsigned long start, unsigned long end,
 				      int node)
 {
 	kasan_pgd_populate(start & PAGE_MASK, PAGE_ALIGN(end), node, false);
 }

 /*
  * Copy the current shadow region into a new pgdir.
  */
 void __init kasan_copy_shadow(pgd_t *pgdir)
 {
 	pgd_t *pgdp, *pgdp_new, *pgdp_end;

 	pgdp = pgd_offset_k(KASAN_SHADOW_START);
 	pgdp_end = pgd_offset_k(KASAN_SHADOW_END);
 	pgdp_new = pgd_offset_pgd(pgdir, KASAN_SHADOW_START);
 	do {
 		set_pgd(pgdp_new, READ_ONCE(*pgdp));
 	} while (pgdp++, pgdp_new++, pgdp != pgdp_end);
 }

 static void __init clear_pgds(unsigned long start,
 			unsigned long end)
 {
 	/*
 	 * Remove references to kasan page tables from
 	 * swapper_pg_dir. pgd_clear() can't be used
 	 * here because it's nop on 2,3-level pagetable setups
 	 */
 	for (; start < end; start += PGDIR_SIZE)
 		set_pgd(pgd_offset_k(start), __pgd(0));
 }

 static void __init kasan_init_shadow(void)
 {
 	u64 kimg_shadow_start, kimg_shadow_end;
 	u64 mod_shadow_start, mod_shadow_end;
 	phys_addr_t pa_start, pa_end;
 	u64 i;

 	kimg_shadow_start = (u64)kasan_mem_to_shadow(_text) & PAGE_MASK;
 	kimg_shadow_end = PAGE_ALIGN((u64)kasan_mem_to_shadow(_end));

 	mod_shadow_start = (u64)kasan_mem_to_shadow((void *)MODULES_VADDR);
 	mod_shadow_end = (u64)kasan_mem_to_shadow((void *)MODULES_END);

 	/*
 	 * We are going to perform proper setup of shadow memory.
 	 * At first we should unmap early shadow (clear_pgds() call below).
 	 * However, instrumented code couldn't execute without shadow memory.
 	 * tmp_pg_dir used to keep early shadow mapped until full shadow
 	 * setup will be finished.
 	 */
 	memcpy(tmp_pg_dir, swapper_pg_dir, sizeof(tmp_pg_dir));
 	dsb(ishst);
 	cpu_replace_ttbr1(lm_alias(tmp_pg_dir));

 	clear_pgds(KASAN_SHADOW_START, KASAN_SHADOW_END);

 	kasan_map_populate(kimg_shadow_start, kimg_shadow_end,
 			   early_pfn_to_nid(virt_to_pfn(lm_alias(_text))));

 	kasan_populate_early_shadow(kasan_mem_to_shadow((void *)PAGE_END),
 				   (void *)mod_shadow_start);
 	kasan_populate_early_shadow((void *)kimg_shadow_end,
 				   (void *)KASAN_SHADOW_END);

 	if (kimg_shadow_start > mod_shadow_end)
 		kasan_populate_early_shadow((void *)mod_shadow_end,
 					    (void *)kimg_shadow_start);

 	for_each_mem_range(i, &pa_start, &pa_end) {
 		void *start = (void *)__phys_to_virt(pa_start);
 		void *end = (void *)__phys_to_virt(pa_end);

 		if (start >= end)
 			break;

 		kasan_map_populate((unsigned long)kasan_mem_to_shadow(start),
 				   (unsigned long)kasan_mem_to_shadow(end),
 				   early_pfn_to_nid(virt_to_pfn(start)));
 	}

 	/*
 	 * KAsan may reuse the contents of kasan_early_shadow_pte directly,
 	 * so we should make sure that it maps the zero page read-only.
 	 */
 	for (i = 0; i < PTRS_PER_PTE; i++)
 		set_pte(&kasan_early_shadow_pte[i],
 			pfn_pte(sym_to_pfn(kasan_early_shadow_page),
 				PAGE_KERNEL_RO));

 	memset(kasan_early_shadow_page, KASAN_SHADOW_INIT, PAGE_SIZE);
 	cpu_replace_ttbr1(lm_alias(swapper_pg_dir));
 }

 static void __init kasan_init_depth(void)
 {
 	init_task.kasan_depth = 0;
 }

 void __init kasan_init(void)
 {
 	kasan_init_shadow();
 	kasan_init_depth();
 #if defined(CONFIG_KASAN_GENERIC)
 	/* CONFIG_KASAN_SW_TAGS also requires kasan_init_sw_tags(). */
 	pr_info("KernelAddressSanitizer initialized\n");
 #endif
 }

 #endif /* CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS */
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* This file contains kasan initialization code for ARM64.
	*
	* Copyright (c) 2015 Samsung Electronics Co., Ltd.
	* Author: Andrey Ryabinin <ryabinin.a.a@gmail.com>
	*/

	#define pr_fmt(fmt) "kasan: " fmt
	#include <linux/kasan.h>
	#include <linux/kernel.h>
	#include <linux/sched/task.h>
	#include <linux/memblock.h>
	#include <linux/start_kernel.h>
	#include <linux/mm.h>

	#include <asm/mmu_context.h>
	#include <asm/kernel-pgtable.h>
	#include <asm/page.h>
	#include <asm/pgalloc.h>
	#include <asm/sections.h>
	#include <asm/tlbflush.h>

	#if defined(CONFIG_KASAN_GENERIC) \|\| defined(CONFIG_KASAN_SW_TAGS)

	static pgd_t tmp_pg_dir[PTRS_PER_PGD] __initdata __aligned(PGD_SIZE);

	/*
	* The p*d_populate functions call virt_to_phys implicitly so they can't be used
	* directly on kernel symbols (bm_p*d). All the early functions are called too
	* early to use lm_alias so __p*d_populate functions must be used to populate
	* with the physical address from __pa_symbol.
	*/

	static phys_addr_t __init kasan_alloc_zeroed_page(int node)
	{
	void *p = memblock_alloc_try_nid(PAGE_SIZE, PAGE_SIZE,
	__pa(MAX_DMA_ADDRESS),
	MEMBLOCK_ALLOC_KASAN, node);
	if (!p)
	panic("%s: Failed to allocate %lu bytes align=0x%lx nid=%d from=%llx\n",
	__func__, PAGE_SIZE, PAGE_SIZE, node,
	__pa(MAX_DMA_ADDRESS));

	return __pa(p);
	}

	static phys_addr_t __init kasan_alloc_raw_page(int node)
	{
	void *p = memblock_alloc_try_nid_raw(PAGE_SIZE, PAGE_SIZE,
	__pa(MAX_DMA_ADDRESS),
	MEMBLOCK_ALLOC_KASAN, node);
	if (!p)
	panic("%s: Failed to allocate %lu bytes align=0x%lx nid=%d from=%llx\n",
	__func__, PAGE_SIZE, PAGE_SIZE, node,
	__pa(MAX_DMA_ADDRESS));

	return __pa(p);
	}

	static pte_t __init kasan_pte_offset(pmd_t pmdp, unsigned long addr, int node,
	bool early)
	{
	if (pmd_none(READ_ONCE(*pmdp))) {
	phys_addr_t pte_phys = early ?
	__pa_symbol(kasan_early_shadow_pte)
	: kasan_alloc_zeroed_page(node);
	__pmd_populate(pmdp, pte_phys, PMD_TYPE_TABLE);
	}

	return early ? pte_offset_kimg(pmdp, addr)
	: pte_offset_kernel(pmdp, addr);
	}

	static pmd_t __init kasan_pmd_offset(pud_t pudp, unsigned long addr, int node,
	bool early)
	{
	if (pud_none(READ_ONCE(*pudp))) {
	phys_addr_t pmd_phys = early ?
	__pa_symbol(kasan_early_shadow_pmd)
	: kasan_alloc_zeroed_page(node);
	__pud_populate(pudp, pmd_phys, PMD_TYPE_TABLE);
	}

	return early ? pmd_offset_kimg(pudp, addr) : pmd_offset(pudp, addr);
	}

	static pud_t __init kasan_pud_offset(p4d_t p4dp, unsigned long addr, int node,
	bool early)
	{
	if (p4d_none(READ_ONCE(*p4dp))) {
	phys_addr_t pud_phys = early ?
	__pa_symbol(kasan_early_shadow_pud)
	: kasan_alloc_zeroed_page(node);
	__p4d_populate(p4dp, pud_phys, PMD_TYPE_TABLE);
	}

	return early ? pud_offset_kimg(p4dp, addr) : pud_offset(p4dp, addr);
	}

	static void __init kasan_pte_populate(pmd_t *pmdp, unsigned long addr,
	unsigned long end, int node, bool early)
	{
	unsigned long next;
	pte_t *ptep = kasan_pte_offset(pmdp, addr, node, early);

	do {
	phys_addr_t page_phys = early ?
	__pa_symbol(kasan_early_shadow_page)
	: kasan_alloc_raw_page(node);
	if (!early)
	memset(__va(page_phys), KASAN_SHADOW_INIT, PAGE_SIZE);
	next = addr + PAGE_SIZE;
	set_pte(ptep, pfn_pte(__phys_to_pfn(page_phys), PAGE_KERNEL));
	} while (ptep++, addr = next, addr != end && pte_none(READ_ONCE(*ptep)));
	}

	static void __init kasan_pmd_populate(pud_t *pudp, unsigned long addr,
	unsigned long end, int node, bool early)
	{
	unsigned long next;
	pmd_t *pmdp = kasan_pmd_offset(pudp, addr, node, early);

	do {
	next = pmd_addr_end(addr, end);
	kasan_pte_populate(pmdp, addr, next, node, early);
	} while (pmdp++, addr = next, addr != end && pmd_none(READ_ONCE(*pmdp)));
	}

	static void __init kasan_pud_populate(p4d_t *p4dp, unsigned long addr,
	unsigned long end, int node, bool early)
	{
	unsigned long next;
	pud_t *pudp = kasan_pud_offset(p4dp, addr, node, early);

	do {
	next = pud_addr_end(addr, end);
	kasan_pmd_populate(pudp, addr, next, node, early);
	} while (pudp++, addr = next, addr != end && pud_none(READ_ONCE(*pudp)));
	}

	static void __init kasan_p4d_populate(pgd_t *pgdp, unsigned long addr,
	unsigned long end, int node, bool early)
	{
	unsigned long next;
	p4d_t *p4dp = p4d_offset(pgdp, addr);

	do {
	next = p4d_addr_end(addr, end);
	kasan_pud_populate(p4dp, addr, next, node, early);
	} while (p4dp++, addr = next, addr != end);
	}

	static void __init kasan_pgd_populate(unsigned long addr, unsigned long end,
	int node, bool early)
	{
	unsigned long next;
	pgd_t *pgdp;

	pgdp = pgd_offset_k(addr);
	do {
	next = pgd_addr_end(addr, end);
	kasan_p4d_populate(pgdp, addr, next, node, early);
	} while (pgdp++, addr = next, addr != end);
	}

	/* The early shadow maps everything to a single page of zeroes */
	asmlinkage void __init kasan_early_init(void)
	{
	BUILD_BUG_ON(KASAN_SHADOW_OFFSET !=
	KASAN_SHADOW_END - (1UL << (64 - KASAN_SHADOW_SCALE_SHIFT)));
	BUILD_BUG_ON(!IS_ALIGNED(_KASAN_SHADOW_START(VA_BITS), PGDIR_SIZE));
	BUILD_BUG_ON(!IS_ALIGNED(_KASAN_SHADOW_START(VA_BITS_MIN), PGDIR_SIZE));
	BUILD_BUG_ON(!IS_ALIGNED(KASAN_SHADOW_END, PGDIR_SIZE));
	kasan_pgd_populate(KASAN_SHADOW_START, KASAN_SHADOW_END, NUMA_NO_NODE,
	true);
	}

	/* Set up full kasan mappings, ensuring that the mapped pages are zeroed */
	static void __init kasan_map_populate(unsigned long start, unsigned long end,
	int node)
	{
	kasan_pgd_populate(start & PAGE_MASK, PAGE_ALIGN(end), node, false);
	}

	/*
	* Copy the current shadow region into a new pgdir.
	*/
	void __init kasan_copy_shadow(pgd_t *pgdir)
	{
	pgd_t pgdp, pgdp_new, *pgdp_end;

	pgdp = pgd_offset_k(KASAN_SHADOW_START);
	pgdp_end = pgd_offset_k(KASAN_SHADOW_END);
	pgdp_new = pgd_offset_pgd(pgdir, KASAN_SHADOW_START);
	do {
	set_pgd(pgdp_new, READ_ONCE(*pgdp));
	} while (pgdp++, pgdp_new++, pgdp != pgdp_end);
	}

	static void __init clear_pgds(unsigned long start,
	unsigned long end)
	{
	/*
	* Remove references to kasan page tables from
	* swapper_pg_dir. pgd_clear() can't be used
	* here because it's nop on 2,3-level pagetable setups
	*/
	for (; start < end; start += PGDIR_SIZE)
	set_pgd(pgd_offset_k(start), __pgd(0));
	}

	static void __init kasan_init_shadow(void)
	{
	u64 kimg_shadow_start, kimg_shadow_end;
	u64 mod_shadow_start, mod_shadow_end;
	phys_addr_t pa_start, pa_end;
	u64 i;

	kimg_shadow_start = (u64)kasan_mem_to_shadow(_text) & PAGE_MASK;
	kimg_shadow_end = PAGE_ALIGN((u64)kasan_mem_to_shadow(_end));

	mod_shadow_start = (u64)kasan_mem_to_shadow((void *)MODULES_VADDR);
	mod_shadow_end = (u64)kasan_mem_to_shadow((void *)MODULES_END);

	/*
	* We are going to perform proper setup of shadow memory.
	* At first we should unmap early shadow (clear_pgds() call below).
	* However, instrumented code couldn't execute without shadow memory.
	* tmp_pg_dir used to keep early shadow mapped until full shadow
	* setup will be finished.
	*/
	memcpy(tmp_pg_dir, swapper_pg_dir, sizeof(tmp_pg_dir));
	dsb(ishst);
	cpu_replace_ttbr1(lm_alias(tmp_pg_dir));

	clear_pgds(KASAN_SHADOW_START, KASAN_SHADOW_END);

	kasan_map_populate(kimg_shadow_start, kimg_shadow_end,
	early_pfn_to_nid(virt_to_pfn(lm_alias(_text))));

	kasan_populate_early_shadow(kasan_mem_to_shadow((void *)PAGE_END),
	(void *)mod_shadow_start);
	kasan_populate_early_shadow((void *)kimg_shadow_end,
	(void *)KASAN_SHADOW_END);

	if (kimg_shadow_start > mod_shadow_end)
	kasan_populate_early_shadow((void *)mod_shadow_end,
	(void *)kimg_shadow_start);

	for_each_mem_range(i, &pa_start, &pa_end) {
	void start = (void )__phys_to_virt(pa_start);
	void end = (void )__phys_to_virt(pa_end);

	if (start >= end)
	break;

	kasan_map_populate((unsigned long)kasan_mem_to_shadow(start),
	(unsigned long)kasan_mem_to_shadow(end),
	early_pfn_to_nid(virt_to_pfn(start)));
	}

	/*
	* KAsan may reuse the contents of kasan_early_shadow_pte directly,
	* so we should make sure that it maps the zero page read-only.
	*/
	for (i = 0; i < PTRS_PER_PTE; i++)
	set_pte(&kasan_early_shadow_pte[i],
	pfn_pte(sym_to_pfn(kasan_early_shadow_page),
	PAGE_KERNEL_RO));

	memset(kasan_early_shadow_page, KASAN_SHADOW_INIT, PAGE_SIZE);
	cpu_replace_ttbr1(lm_alias(swapper_pg_dir));
	}

	static void __init kasan_init_depth(void)
	{
	init_task.kasan_depth = 0;
	}

	void __init kasan_init(void)
	{
	kasan_init_shadow();
	kasan_init_depth();
	#if defined(CONFIG_KASAN_GENERIC)
	/* CONFIG_KASAN_SW_TAGS also requires kasan_init_sw_tags(). */
	pr_info("KernelAddressSanitizer initialized\n");
	#endif
	}

	#endif /* CONFIG_KASAN_GENERIC \|\| CONFIG_KASAN_SW_TAGS */