1 files changed, 206 insertions, 0 deletions
diff --git a/arch/x86/mm/kasan_init_64.c b/arch/x86/mm/kasan_init_64.c
new file mode 100644
index 000000000000..4860906c6b9f
--- /dev/null
+++ b/arch/x86/mm/kasan_init_64.c
@@ -0,0 +1,206 @@
+#include <linux/bootmem.h>
+#include <linux/kasan.h>
+#include <linux/kdebug.h>
+#include <linux/mm.h>
+#include <linux/sched.h>
+#include <linux/vmalloc.h>
+
+#include <asm/tlbflush.h>
+#include <asm/sections.h>
+
+extern pgd_t early_level4_pgt[PTRS_PER_PGD];
+extern struct range pfn_mapped[E820_X_MAX];
+
+extern unsigned char kasan_zero_page[PAGE_SIZE];
+
+static int __init map_range(struct range *range)
+{
+	unsigned long start;
+	unsigned long end;
+
+	start = (unsigned long)kasan_mem_to_shadow(pfn_to_kaddr(range->start));
+	end = (unsigned long)kasan_mem_to_shadow(pfn_to_kaddr(range->end));
+
+	/*
+	 * 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.
+	 */
+	return vmemmap_populate(start, end + 1, NUMA_NO_NODE);
+}
+
+static void __init clear_pgds(unsigned long start,
+			unsigned long end)
+{
+	for (; start < end; start += PGDIR_SIZE)
+		pgd_clear(pgd_offset_k(start));
+}
+
+void __init kasan_map_early_shadow(pgd_t *pgd)
+{
+	int i;
+	unsigned long start = KASAN_SHADOW_START;
+	unsigned long end = KASAN_SHADOW_END;
+
+	for (i = pgd_index(start); start < end; i++) {
+		pgd[i] = __pgd(__pa_nodebug(kasan_zero_pud)
+				| _KERNPG_TABLE);
+		start += PGDIR_SIZE;
+	}
+}
+
+static int __init zero_pte_populate(pmd_t *pmd, unsigned long addr,
+				unsigned long end)
+{
+	pte_t *pte = pte_offset_kernel(pmd, addr);
+
+	while (addr + PAGE_SIZE <= end) {
+		WARN_ON(!pte_none(*pte));
+		set_pte(pte, __pte(__pa_nodebug(kasan_zero_page)
+					| __PAGE_KERNEL_RO));
+		addr += PAGE_SIZE;
+		pte = pte_offset_kernel(pmd, addr);
+	}
+	return 0;
+}
+
+static int __init zero_pmd_populate(pud_t *pud, unsigned long addr,
+				unsigned long end)
+{
+	int ret = 0;
+	pmd_t *pmd = pmd_offset(pud, addr);
+
+	while (IS_ALIGNED(addr, PMD_SIZE) && addr + PMD_SIZE <= end) {
+		WARN_ON(!pmd_none(*pmd));
+		set_pmd(pmd, __pmd(__pa_nodebug(kasan_zero_pte)
+					| __PAGE_KERNEL_RO));
+		addr += PMD_SIZE;
+		pmd = pmd_offset(pud, addr);
+	}
+	if (addr < end) {
+		if (pmd_none(*pmd)) {
+			void *p = vmemmap_alloc_block(PAGE_SIZE, NUMA_NO_NODE);
+			if (!p)
+				return -ENOMEM;
+			set_pmd(pmd, __pmd(__pa_nodebug(p) | _KERNPG_TABLE));
+		}
+		ret = zero_pte_populate(pmd, addr, end);
+	}
+	return ret;
+}
+
+
+static int __init zero_pud_populate(pgd_t *pgd, unsigned long addr,
+				unsigned long end)
+{
+	int ret = 0;
+	pud_t *pud = pud_offset(pgd, addr);
+
+	while (IS_ALIGNED(addr, PUD_SIZE) && addr + PUD_SIZE <= end) {
+		WARN_ON(!pud_none(*pud));
+		set_pud(pud, __pud(__pa_nodebug(kasan_zero_pmd)
+					| __PAGE_KERNEL_RO));
+		addr += PUD_SIZE;
+		pud = pud_offset(pgd, addr);
+	}
+
+	if (addr < end) {
+		if (pud_none(*pud)) {
+			void *p = vmemmap_alloc_block(PAGE_SIZE, NUMA_NO_NODE);
+			if (!p)
+				return -ENOMEM;
+			set_pud(pud, __pud(__pa_nodebug(p) | _KERNPG_TABLE));
+		}
+		ret = zero_pmd_populate(pud, addr, end);
+	}
+	return ret;
+}
+
+static int __init zero_pgd_populate(unsigned long addr, unsigned long end)
+{
+	int ret = 0;
+	pgd_t *pgd = pgd_offset_k(addr);
+
+	while (IS_ALIGNED(addr, PGDIR_SIZE) && addr + PGDIR_SIZE <= end) {
+		WARN_ON(!pgd_none(*pgd));
+		set_pgd(pgd, __pgd(__pa_nodebug(kasan_zero_pud)
+					| __PAGE_KERNEL_RO));
+		addr += PGDIR_SIZE;
+		pgd = pgd_offset_k(addr);
+	}
+
+	if (addr < end) {
+		if (pgd_none(*pgd)) {
+			void *p = vmemmap_alloc_block(PAGE_SIZE, NUMA_NO_NODE);
+			if (!p)
+				return -ENOMEM;
+			set_pgd(pgd, __pgd(__pa_nodebug(p) | _KERNPG_TABLE));
+		}
+		ret = zero_pud_populate(pgd, addr, end);
+	}
+	return ret;
+}
+
+
+static void __init populate_zero_shadow(const void *start, const void *end)
+{
+	if (zero_pgd_populate((unsigned long)start, (unsigned long)end))
+		panic("kasan: unable to map zero shadow!");
+}
+
+
+#ifdef CONFIG_KASAN_INLINE
+static int kasan_die_handler(struct notifier_block *self,
+			     unsigned long val,
+			     void *data)
+{
+	if (val == DIE_GPF) {
+		pr_emerg("CONFIG_KASAN_INLINE enabled");
+		pr_emerg("GPF could be caused by NULL-ptr deref or user memory access");
+	}
+	return NOTIFY_OK;
+}
+
+static struct notifier_block kasan_die_notifier = {
+	.notifier_call = kasan_die_handler,
+};
+#endif
+
+void __init kasan_init(void)
+{
+	int i;
+
+#ifdef CONFIG_KASAN_INLINE
+	register_die_notifier(&kasan_die_notifier);
+#endif
+
+	memcpy(early_level4_pgt, init_level4_pgt, sizeof(early_level4_pgt));
+	load_cr3(early_level4_pgt);
+
+	clear_pgds(KASAN_SHADOW_START, KASAN_SHADOW_END);
+
+	populate_zero_shadow((void *)KASAN_SHADOW_START,
+			kasan_mem_to_shadow((void *)PAGE_OFFSET));
+
+	for (i = 0; i < E820_X_MAX; i++) {
+		if (pfn_mapped[i].end == 0)
+			break;
+
+		if (map_range(&pfn_mapped[i]))
+			panic("kasan: unable to allocate shadow!");
+	}
+	populate_zero_shadow(kasan_mem_to_shadow((void *)PAGE_OFFSET + MAXMEM),
+			kasan_mem_to_shadow((void *)__START_KERNEL_map));
+
+	vmemmap_populate((unsigned long)kasan_mem_to_shadow(_stext),
+			(unsigned long)kasan_mem_to_shadow(_end),
+			NUMA_NO_NODE);
+
+	populate_zero_shadow(kasan_mem_to_shadow((void *)MODULES_END),
+			(void *)KASAN_SHADOW_END);
+
+	memset(kasan_zero_page, 0, PAGE_SIZE);
+
+	load_cr3(init_level4_pgt);
+	init_task.kasan_depth = 0;
+}