summaryrefslogtreecommitdiffstats
path: root/arch/arm64/mm/kasan_init.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/arm64/mm/kasan_init.c')
-rw-r--r--arch/arm64/mm/kasan_init.c317
1 files changed, 317 insertions, 0 deletions
diff --git a/arch/arm64/mm/kasan_init.c b/arch/arm64/mm/kasan_init.c
new file mode 100644
index 000000000..e969e68de
--- /dev/null
+++ b/arch/arm64/mm/kasan_init.c
@@ -0,0 +1,317 @@
+// 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_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 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;
+ u64 vmalloc_shadow_end;
+ phys_addr_t pa_start, pa_end;
+ u64 i;
+
+ 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 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), idmap_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(KERNEL_START))));
+
+ kasan_populate_early_shadow(kasan_mem_to_shadow((void *)PAGE_END),
+ (void *)mod_shadow_start);
+
+ if (IS_ENABLED(CONFIG_KASAN_VMALLOC)) {
+ BUILD_BUG_ON(VMALLOC_START != MODULES_END);
+ kasan_populate_early_shadow((void *)vmalloc_shadow_end,
+ (void *)KASAN_SHADOW_END);
+ } else {
+ 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), idmap_pg_dir);
+}
+
+static void __init kasan_init_depth(void)
+{
+ init_task.kasan_depth = 0;
+}
+
+#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();
+#if defined(CONFIG_KASAN_GENERIC)
+ /* CONFIG_KASAN_SW_TAGS also requires kasan_init_sw_tags(). */
+ pr_info("KernelAddressSanitizer initialized (generic)\n");
+#endif
+}
+
+#endif /* CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS */