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-rw-r--r--arch/arm64/mm/kasan_init.c165
1 files changed, 165 insertions, 0 deletions
diff --git a/arch/arm64/mm/kasan_init.c b/arch/arm64/mm/kasan_init.c
new file mode 100644
index 000000000000..cf038c7d9fa9
--- /dev/null
+++ b/arch/arm64/mm/kasan_init.c
@@ -0,0 +1,165 @@
+/*
+ * 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
+#include <linux/kasan.h>
+#include <linux/kernel.h>
+#include <linux/memblock.h>
+#include <linux/start_kernel.h>
+
+#include <asm/page.h>
+#include <asm/pgalloc.h>
+#include <asm/pgtable.h>
+#include <asm/tlbflush.h>
+
+static pgd_t tmp_pg_dir[PTRS_PER_PGD] __initdata __aligned(PGD_SIZE);
+
+static void __init kasan_early_pte_populate(pmd_t *pmd, unsigned long addr,
+ unsigned long end)
+{
+ pte_t *pte;
+ unsigned long next;
+
+ if (pmd_none(*pmd))
+ pmd_populate_kernel(&init_mm, pmd, kasan_zero_pte);
+
+ pte = pte_offset_kernel(pmd, addr);
+ do {
+ next = addr + PAGE_SIZE;
+ set_pte(pte, pfn_pte(virt_to_pfn(kasan_zero_page),
+ PAGE_KERNEL));
+ } while (pte++, addr = next, addr != end && pte_none(*pte));
+}
+
+static void __init kasan_early_pmd_populate(pud_t *pud,
+ unsigned long addr,
+ unsigned long end)
+{
+ pmd_t *pmd;
+ unsigned long next;
+
+ if (pud_none(*pud))
+ pud_populate(&init_mm, pud, kasan_zero_pmd);
+
+ pmd = pmd_offset(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));
+}
+
+static void __init kasan_early_pud_populate(pgd_t *pgd,
+ unsigned long addr,
+ unsigned long end)
+{
+ pud_t *pud;
+ unsigned long next;
+
+ if (pgd_none(*pgd))
+ pgd_populate(&init_mm, pgd, kasan_zero_pud);
+
+ pud = pud_offset(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));
+}
+
+static void __init kasan_map_early_shadow(void)
+{
+ unsigned long addr = KASAN_SHADOW_START;
+ unsigned long end = KASAN_SHADOW_END;
+ unsigned long next;
+ pgd_t *pgd;
+
+ 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);
+}
+
+asmlinkage void __init kasan_early_init(void)
+{
+ 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();
+}
+
+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 cpu_set_ttbr1(unsigned long ttbr1)
+{
+ asm(
+ " msr ttbr1_el1, %0\n"
+ " isb"
+ :
+ : "r" (ttbr1));
+}
+
+void __init kasan_init(void)
+{
+ struct memblock_region *reg;
+
+ /*
+ * We are going to perform proper setup of shadow memory.
+ * At first we should unmap early shadow (clear_pgds() call bellow).
+ * 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));
+ cpu_set_ttbr1(__pa(tmp_pg_dir));
+ flush_tlb_all();
+
+ clear_pgds(KASAN_SHADOW_START, KASAN_SHADOW_END);
+
+ kasan_populate_zero_shadow((void *)KASAN_SHADOW_START,
+ kasan_mem_to_shadow((void *)MODULES_VADDR));
+
+ for_each_memblock(memory, reg) {
+ void *start = (void *)__phys_to_virt(reg->base);
+ void *end = (void *)__phys_to_virt(reg->base + reg->size);
+
+ if (start >= end)
+ break;
+
+ /*
+ * end + 1 here is intentional. We check several shadow bytes in
+ * advance to slightly speed up fastpath. In some rare cases
+ * we could cross boundary of mapped shadow, so we just map
+ * some more here.
+ */
+ vmemmap_populate((unsigned long)kasan_mem_to_shadow(start),
+ (unsigned long)kasan_mem_to_shadow(end) + 1,
+ pfn_to_nid(virt_to_pfn(start)));
+ }
+
+ memset(kasan_zero_page, 0, PAGE_SIZE);
+ cpu_set_ttbr1(__pa(swapper_pg_dir));
+ flush_tlb_all();
+
+ /* At this point kasan is fully initialized. Enable error messages */
+ init_task.kasan_depth = 0;
+ pr_info("KernelAddressSanitizer initialized\n");
+}