1 files changed, 304 insertions, 107 deletions

diff --git a/arch/arm64/mm/kasan_init.c b/arch/arm64/mm/kasan_init.c
index 81f03959a4ab..abeb81bf6ebd 100644
--- a/arch/arm64/mm/kasan_init.c
+++ b/arch/arm64/mm/kasan_init.c
@@ -1,13 +1,9 @@
+// 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>
- *
- * 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.
- *
  */
 
 #define pr_fmt(fmt) "kasan: " fmt
@@ -22,11 +18,12 @@
 #include <asm/kernel-pgtable.h>
 #include <asm/page.h>
 #include <asm/pgalloc.h>
-#include <asm/pgtable.h>
 #include <asm/sections.h>
 #include <asm/tlbflush.h>
 
-static pgd_t tmp_pg_dir[PTRS_PER_PGD] __initdata __aligned(PGD_SIZE);
+#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
+
+static pgd_t tmp_pg_dir[PTRS_PER_PTE] __initdata __aligned(PAGE_SIZE);
 
 /*
  * The p*d_populate functions call virt_to_phys implicitly so they can't be used
@@ -35,179 +32,379 @@ static pgd_t tmp_pg_dir[PTRS_PER_PGD] __initdata __aligned(PGD_SIZE);
  * with the physical address from __pa_symbol.
  */
 
-static void __init kasan_early_pte_populate(pmd_t *pmd, unsigned long addr,
-					unsigned long end)
+static phys_addr_t __init kasan_alloc_zeroed_page(int node)
 {
-	pte_t *pte;
-	unsigned long next;
+	void *p = memblock_alloc_try_nid(PAGE_SIZE, PAGE_SIZE,
+					      __pa(MAX_DMA_ADDRESS),
+					      MEMBLOCK_ALLOC_NOLEAKTRACE, 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_NOLEAKTRACE,
+						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, PUD_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, P4D_TYPE_TABLE);
+	}
+
+	return early ? pud_offset_kimg(p4dp, addr) : pud_offset(p4dp, addr);
+}
+
+static p4d_t *__init kasan_p4d_offset(pgd_t *pgdp, unsigned long addr, int node,
+				      bool early)
+{
+	if (pgd_none(READ_ONCE(*pgdp))) {
+		phys_addr_t p4d_phys = early ?
+				__pa_symbol(kasan_early_shadow_p4d)
+					: kasan_alloc_zeroed_page(node);
+		__pgd_populate(pgdp, p4d_phys, PGD_TYPE_TABLE);
+	}
+
+	return early ? p4d_offset_kimg(pgdp, addr) : p4d_offset(pgdp, addr);
+}
 
-	if (pmd_none(*pmd))
-		__pmd_populate(pmd, __pa_symbol(kasan_zero_pte), PMD_TYPE_TABLE);
+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);
 
-	pte = pte_offset_kimg(pmd, addr);
 	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(pte, pfn_pte(sym_to_pfn(kasan_zero_page),
-					PAGE_KERNEL));
-	} while (pte++, addr = next, addr != end && pte_none(*pte));
+		__set_pte(ptep, pfn_pte(__phys_to_pfn(page_phys), PAGE_KERNEL));
+	} while (ptep++, addr = next, addr != end && pte_none(__ptep_get(ptep)));
 }
 
-static void __init kasan_early_pmd_populate(pud_t *pud,
-					unsigned long addr,
-					unsigned long end)
+static void __init kasan_pmd_populate(pud_t *pudp, unsigned long addr,
+				      unsigned long end, int node, bool early)
 {
-	pmd_t *pmd;
 	unsigned long next;
+	pmd_t *pmdp = kasan_pmd_offset(pudp, addr, node, early);
 
-	if (pud_none(*pud))
-		__pud_populate(pud, __pa_symbol(kasan_zero_pmd), PMD_TYPE_TABLE);
-
-	pmd = pmd_offset_kimg(pud, addr);
 	do {
 		next = pmd_addr_end(addr, end);
-		kasan_early_pte_populate(pmd, addr, next);
-	} while (pmd++, addr = next, addr != end && pmd_none(*pmd));
+		kasan_pte_populate(pmdp, addr, next, node, early);
+	} while (pmdp++, addr = next, addr != end && pmd_none(READ_ONCE(*pmdp)));
 }
 
-static void __init kasan_early_pud_populate(pgd_t *pgd,
-					unsigned long addr,
-					unsigned long end)
+static void __init kasan_pud_populate(p4d_t *p4dp, unsigned long addr,
+				      unsigned long end, int node, bool early)
 {
-	pud_t *pud;
 	unsigned long next;
+	pud_t *pudp = kasan_pud_offset(p4dp, addr, node, early);
 
-	if (pgd_none(*pgd))
-		__pgd_populate(pgd, __pa_symbol(kasan_zero_pud), PUD_TYPE_TABLE);
-
-	pud = pud_offset_kimg(pgd, addr);
 	do {
 		next = pud_addr_end(addr, end);
-		kasan_early_pmd_populate(pud, addr, next);
-	} while (pud++, addr = next, addr != end && pud_none(*pud));
+		kasan_pmd_populate(pudp, addr, next, node, early);
+	} while (pudp++, addr = next, addr != end && pud_none(READ_ONCE(*pudp)));
 }
 
-static void __init kasan_map_early_shadow(void)
+static void __init kasan_p4d_populate(pgd_t *pgdp, unsigned long addr,
+				      unsigned long end, int node, bool early)
 {
-	unsigned long addr = KASAN_SHADOW_START;
-	unsigned long end = KASAN_SHADOW_END;
 	unsigned long next;
-	pgd_t *pgd;
+	p4d_t *p4dp = kasan_p4d_offset(pgdp, addr, node, early);
 
-	pgd = pgd_offset_k(addr);
 	do {
-		next = pgd_addr_end(addr, end);
-		kasan_early_pud_populate(pgd, addr, next);
-	} while (pgd++, addr = next, addr != end);
+		next = p4d_addr_end(addr, end);
+		kasan_pud_populate(p4dp, addr, next, node, early);
+	} while (p4dp++, addr = next, addr != end && p4d_none(READ_ONCE(*p4dp)));
 }
 
-asmlinkage void __init kasan_early_init(void)
+static void __init kasan_pgd_populate(unsigned long addr, unsigned long end,
+				      int node, bool early)
 {
-	BUILD_BUG_ON(KASAN_SHADOW_OFFSET != KASAN_SHADOW_END - (1UL << 61));
-	BUILD_BUG_ON(!IS_ALIGNED(KASAN_SHADOW_START, PGDIR_SIZE));
-	BUILD_BUG_ON(!IS_ALIGNED(KASAN_SHADOW_END, PGDIR_SIZE));
-	kasan_map_early_shadow();
+	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);
 }
 
+#if defined(CONFIG_ARM64_64K_PAGES) || CONFIG_PGTABLE_LEVELS > 4
+#define SHADOW_ALIGN	P4D_SIZE
+#else
+#define SHADOW_ALIGN	PUD_SIZE
+#endif
+
 /*
- * Copy the current shadow region into a new pgdir.
+ * Return whether 'addr' is aligned to the size covered by a root level
+ * descriptor.
  */
-void __init kasan_copy_shadow(pgd_t *pgdir)
+static bool __init root_level_aligned(u64 addr)
 {
-	pgd_t *pgd, *pgd_new, *pgd_end;
+	int shift = (ARM64_HW_PGTABLE_LEVELS(vabits_actual) - 1) * PTDESC_TABLE_SHIFT;
 
-	pgd = pgd_offset_k(KASAN_SHADOW_START);
-	pgd_end = pgd_offset_k(KASAN_SHADOW_END);
-	pgd_new = pgd_offset_raw(pgdir, KASAN_SHADOW_START);
-	do {
-		set_pgd(pgd_new, *pgd);
-	} while (pgd++, pgd_new++, pgd != pgd_end);
+	return (addr % (PAGE_SIZE << shift)) == 0;
+}
+
+/* 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), SHADOW_ALIGN));
+	BUILD_BUG_ON(!IS_ALIGNED(_KASAN_SHADOW_START(VA_BITS_MIN), SHADOW_ALIGN));
+	BUILD_BUG_ON(!IS_ALIGNED(KASAN_SHADOW_END, SHADOW_ALIGN));
+
+	if (!root_level_aligned(KASAN_SHADOW_START)) {
+		/*
+		 * The start address is misaligned, and so the next level table
+		 * will be shared with the linear region. This can happen with
+		 * 4 or 5 level paging, so install a generic pte_t[] as the
+		 * next level. This prevents the kasan_pgd_populate call below
+		 * from inserting an entry that refers to the shared KASAN zero
+		 * shadow pud_t[]/p4d_t[], which could end up getting corrupted
+		 * when the linear region is mapped.
+		 */
+		static pte_t tbl[PTRS_PER_PTE] __page_aligned_bss;
+		pgd_t *pgdp = pgd_offset_k(KASAN_SHADOW_START);
+
+		set_pgd(pgdp, __pgd(__pa_symbol(tbl) | PGD_TYPE_TABLE));
+	}
+
+	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);
 }
 
-static void __init clear_pgds(unsigned long start,
-			unsigned long end)
+/*
+ * Return the descriptor index of 'addr' in the root level table
+ */
+static int __init root_level_idx(u64 addr)
 {
 	/*
-	 * 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
+	 * On 64k pages, the TTBR1 range root tables are extended for 52-bit
+	 * virtual addressing, and TTBR1 will simply point to the pgd_t entry
+	 * that covers the start of the 48-bit addressable VA space if LVA is
+	 * not implemented. This means we need to index the table as usual,
+	 * instead of masking off bits based on vabits_actual.
 	 */
-	for (; start < end; start += PGDIR_SIZE)
-		set_pgd(pgd_offset_k(start), __pgd(0));
+	u64 vabits = IS_ENABLED(CONFIG_ARM64_64K_PAGES) ? VA_BITS
+							: vabits_actual;
+	int shift = (ARM64_HW_PGTABLE_LEVELS(vabits) - 1) * PTDESC_TABLE_SHIFT;
+
+	return (addr & ~_PAGE_OFFSET(vabits)) >> (shift + PAGE_SHIFT);
 }
 
-void __init kasan_init(void)
+/*
+ * Clone a next level table from swapper_pg_dir into tmp_pg_dir
+ */
+static void __init clone_next_level(u64 addr, pgd_t *tmp_pg_dir, pud_t *pud)
+{
+	int idx = root_level_idx(addr);
+	pgd_t pgd = READ_ONCE(swapper_pg_dir[idx]);
+	pud_t *pudp = (pud_t *)__phys_to_kimg(__pgd_to_phys(pgd));
+
+	memcpy(pud, pudp, PAGE_SIZE);
+	tmp_pg_dir[idx] = __pgd(__phys_to_pgd_val(__pa_symbol(pud)) |
+				PUD_TYPE_TABLE);
+}
+
+/*
+ * Return the descriptor index of 'addr' in the next level table
+ */
+static int __init next_level_idx(u64 addr)
+{
+	int shift = (ARM64_HW_PGTABLE_LEVELS(vabits_actual) - 2) * PTDESC_TABLE_SHIFT;
+
+	return (addr >> (shift + PAGE_SHIFT)) % PTRS_PER_PTE;
+}
+
+/*
+ * Dereference the table descriptor at 'pgd_idx' and clear the entries from
+ * 'start' to 'end' (exclusive) from the table.
+ */
+static void __init clear_next_level(int pgd_idx, int start, int end)
+{
+	pgd_t pgd = READ_ONCE(swapper_pg_dir[pgd_idx]);
+	pud_t *pudp = (pud_t *)__phys_to_kimg(__pgd_to_phys(pgd));
+
+	memset(&pudp[start], 0, (end - start) * sizeof(pud_t));
+}
+
+static void __init clear_shadow(u64 start, u64 end)
+{
+	int l = root_level_idx(start), m = root_level_idx(end);
+
+	if (!root_level_aligned(start))
+		clear_next_level(l++, next_level_idx(start), PTRS_PER_PTE);
+	if (!root_level_aligned(end))
+		clear_next_level(m, 0, next_level_idx(end));
+	memset(&swapper_pg_dir[l], 0, (m - l) * sizeof(pgd_t));
+}
+
+static void __init kasan_init_shadow(void)
 {
+	static pud_t pud[2][PTRS_PER_PUD] __initdata __aligned(PAGE_SIZE);
 	u64 kimg_shadow_start, kimg_shadow_end;
-	u64 mod_shadow_start, mod_shadow_end;
-	struct memblock_region *reg;
-	int i;
+	u64 mod_shadow_start;
+	u64 vmalloc_shadow_end;
+	phys_addr_t pa_start, pa_end;
+	u64 i;
 
-	kimg_shadow_start = (u64)kasan_mem_to_shadow(_text);
-	kimg_shadow_end = (u64)kasan_mem_to_shadow(_end);
+	kimg_shadow_start = (u64)kasan_mem_to_shadow(KERNEL_START) & PAGE_MASK;
+	kimg_shadow_end = PAGE_ALIGN((u64)kasan_mem_to_shadow(KERNEL_END));
 
 	mod_shadow_start = (u64)kasan_mem_to_shadow((void *)MODULES_VADDR);
-	mod_shadow_end = (u64)kasan_mem_to_shadow((void *)MODULES_END);
+
+	vmalloc_shadow_end = (u64)kasan_mem_to_shadow((void *)VMALLOC_END);
 
 	/*
 	 * We are going to perform proper setup of shadow memory.
-	 * At first we should unmap early shadow (clear_pgds() call bellow).
+	 * 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));
+
+	/*
+	 * If the start or end address of the shadow region is not aligned to
+	 * the root level size, we have to allocate a temporary next-level table
+	 * in each case, clone the next level of descriptors, and install the
+	 * table into tmp_pg_dir. Note that with 5 levels of paging, the next
+	 * level will in fact be p4d_t, but that makes no difference in this
+	 * case.
+	 */
+	if (!root_level_aligned(KASAN_SHADOW_START))
+		clone_next_level(KASAN_SHADOW_START, tmp_pg_dir, pud[0]);
+	if (!root_level_aligned(KASAN_SHADOW_END))
+		clone_next_level(KASAN_SHADOW_END, tmp_pg_dir, pud[1]);
 	dsb(ishst);
 	cpu_replace_ttbr1(lm_alias(tmp_pg_dir));
 
-	clear_pgds(KASAN_SHADOW_START, KASAN_SHADOW_END);
-
-	vmemmap_populate(kimg_shadow_start, kimg_shadow_end,
-			 pfn_to_nid(virt_to_pfn(lm_alias(_text))));
+	clear_shadow(KASAN_SHADOW_START, KASAN_SHADOW_END);
 
-	/*
-	 * vmemmap_populate() has populated the shadow region that covers the
-	 * kernel image with SWAPPER_BLOCK_SIZE mappings, so we have to round
-	 * the start and end addresses to SWAPPER_BLOCK_SIZE as well, to prevent
-	 * kasan_populate_zero_shadow() from replacing the page table entries
-	 * (PMD or PTE) at the edges of the shadow region for the kernel
-	 * image.
-	 */
-	kimg_shadow_start = round_down(kimg_shadow_start, SWAPPER_BLOCK_SIZE);
-	kimg_shadow_end = round_up(kimg_shadow_end, SWAPPER_BLOCK_SIZE);
+	kasan_map_populate(kimg_shadow_start, kimg_shadow_end,
+			   early_pfn_to_nid(virt_to_pfn(lm_alias(KERNEL_START))));
 
-	kasan_populate_zero_shadow((void *)KASAN_SHADOW_START,
+	kasan_populate_early_shadow(kasan_mem_to_shadow((void *)PAGE_END),
 				   (void *)mod_shadow_start);
-	kasan_populate_zero_shadow((void *)kimg_shadow_end,
-				   kasan_mem_to_shadow((void *)PAGE_OFFSET));
 
-	if (kimg_shadow_start > mod_shadow_end)
-		kasan_populate_zero_shadow((void *)mod_shadow_end,
-					   (void *)kimg_shadow_start);
+	BUILD_BUG_ON(VMALLOC_START != MODULES_END);
+	kasan_populate_early_shadow((void *)vmalloc_shadow_end,
+				    (void *)KASAN_SHADOW_END);
 
-	for_each_memblock(memory, reg) {
-		void *start = (void *)__phys_to_virt(reg->base);
-		void *end = (void *)__phys_to_virt(reg->base + reg->size);
+	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;
 
-		vmemmap_populate((unsigned long)kasan_mem_to_shadow(start),
-				(unsigned long)kasan_mem_to_shadow(end),
-				pfn_to_nid(virt_to_pfn(start)));
+		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_zero_pte directly, so we
-	 * should make sure that it maps the zero page read-only.
+	 * 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_zero_pte[i],
-			pfn_pte(sym_to_pfn(kasan_zero_page), PAGE_KERNEL_RO));
+		__set_pte(&kasan_early_shadow_pte[i],
+			pfn_pte(sym_to_pfn(kasan_early_shadow_page),
+				PAGE_KERNEL_RO));
 
-	memset(kasan_zero_page, 0, PAGE_SIZE);
+	memset(kasan_early_shadow_page, KASAN_SHADOW_INIT, PAGE_SIZE);
 	cpu_replace_ttbr1(lm_alias(swapper_pg_dir));
+}
 
-	/* At this point kasan is fully initialized. Enable error messages */
+static void __init kasan_init_depth(void)
+{
 	init_task.kasan_depth = 0;
-	pr_info("KernelAddressSanitizer initialized\n");
 }
+
+#ifdef CONFIG_KASAN_VMALLOC
+void __init kasan_populate_early_vm_area_shadow(void *start, unsigned long size)
+{
+	unsigned long shadow_start, shadow_end;
+
+	if (!is_vmalloc_or_module_addr(start))
+		return;
+
+	shadow_start = (unsigned long)kasan_mem_to_shadow(start);
+	shadow_start = ALIGN_DOWN(shadow_start, PAGE_SIZE);
+	shadow_end = (unsigned long)kasan_mem_to_shadow(start + size);
+	shadow_end = ALIGN(shadow_end, PAGE_SIZE);
+	kasan_map_populate(shadow_start, shadow_end, NUMA_NO_NODE);
+}
+#endif
+
+void __init kasan_init(void)
+{
+	kasan_init_shadow();
+	kasan_init_depth();
+	kasan_init_generic();
+	/*
+	 * Generic KASAN is now fully initialized.
+	 * Software and Hardware Tag-Based modes still require
+	 * kasan_init_sw_tags() and kasan_init_hw_tags() correspondingly.
+	 */
+}
+
+#endif /* CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS */