1 files changed, 433 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 000000000..e7b9b464a
--- /dev/null
+++ b/arch/x86/mm/kasan_init_64.c
@@ -0,0 +1,433 @@
+// SPDX-License-Identifier: GPL-2.0
+#define DISABLE_BRANCH_PROFILING
+#define pr_fmt(fmt) "kasan: " fmt
+
+/* cpu_feature_enabled() cannot be used this early */
+#define USE_EARLY_PGTABLE_L5
+
+#include <linux/memblock.h>
+#include <linux/kasan.h>
+#include <linux/kdebug.h>
+#include <linux/mm.h>
+#include <linux/sched.h>
+#include <linux/sched/task.h>
+#include <linux/vmalloc.h>
+
+#include <asm/e820/types.h>
+#include <asm/pgalloc.h>
+#include <asm/tlbflush.h>
+#include <asm/sections.h>
+#include <asm/cpu_entry_area.h>
+
+extern struct range pfn_mapped[E820_MAX_ENTRIES];
+
+static p4d_t tmp_p4d_table[MAX_PTRS_PER_P4D] __initdata __aligned(PAGE_SIZE);
+
+static __init void *early_alloc(size_t size, int nid, bool should_panic)
+{
+	void *ptr = memblock_alloc_try_nid(size, size,
+			__pa(MAX_DMA_ADDRESS), MEMBLOCK_ALLOC_ACCESSIBLE, nid);
+
+	if (!ptr && should_panic)
+		panic("%pS: Failed to allocate page, nid=%d from=%lx\n",
+		      (void *)_RET_IP_, nid, __pa(MAX_DMA_ADDRESS));
+
+	return ptr;
+}
+
+static void __init kasan_populate_pmd(pmd_t *pmd, unsigned long addr,
+				      unsigned long end, int nid)
+{
+	pte_t *pte;
+
+	if (pmd_none(*pmd)) {
+		void *p;
+
+		if (boot_cpu_has(X86_FEATURE_PSE) &&
+		    ((end - addr) == PMD_SIZE) &&
+		    IS_ALIGNED(addr, PMD_SIZE)) {
+			p = early_alloc(PMD_SIZE, nid, false);
+			if (p && pmd_set_huge(pmd, __pa(p), PAGE_KERNEL))
+				return;
+			memblock_free(p, PMD_SIZE);
+		}
+
+		p = early_alloc(PAGE_SIZE, nid, true);
+		pmd_populate_kernel(&init_mm, pmd, p);
+	}
+
+	pte = pte_offset_kernel(pmd, addr);
+	do {
+		pte_t entry;
+		void *p;
+
+		if (!pte_none(*pte))
+			continue;
+
+		p = early_alloc(PAGE_SIZE, nid, true);
+		entry = pfn_pte(PFN_DOWN(__pa(p)), PAGE_KERNEL);
+		set_pte_at(&init_mm, addr, pte, entry);
+	} while (pte++, addr += PAGE_SIZE, addr != end);
+}
+
+static void __init kasan_populate_pud(pud_t *pud, unsigned long addr,
+				      unsigned long end, int nid)
+{
+	pmd_t *pmd;
+	unsigned long next;
+
+	if (pud_none(*pud)) {
+		void *p;
+
+		if (boot_cpu_has(X86_FEATURE_GBPAGES) &&
+		    ((end - addr) == PUD_SIZE) &&
+		    IS_ALIGNED(addr, PUD_SIZE)) {
+			p = early_alloc(PUD_SIZE, nid, false);
+			if (p && pud_set_huge(pud, __pa(p), PAGE_KERNEL))
+				return;
+			memblock_free(p, PUD_SIZE);
+		}
+
+		p = early_alloc(PAGE_SIZE, nid, true);
+		pud_populate(&init_mm, pud, p);
+	}
+
+	pmd = pmd_offset(pud, addr);
+	do {
+		next = pmd_addr_end(addr, end);
+		if (!pmd_large(*pmd))
+			kasan_populate_pmd(pmd, addr, next, nid);
+	} while (pmd++, addr = next, addr != end);
+}
+
+static void __init kasan_populate_p4d(p4d_t *p4d, unsigned long addr,
+				      unsigned long end, int nid)
+{
+	pud_t *pud;
+	unsigned long next;
+
+	if (p4d_none(*p4d)) {
+		void *p = early_alloc(PAGE_SIZE, nid, true);
+
+		p4d_populate(&init_mm, p4d, p);
+	}
+
+	pud = pud_offset(p4d, addr);
+	do {
+		next = pud_addr_end(addr, end);
+		if (!pud_large(*pud))
+			kasan_populate_pud(pud, addr, next, nid);
+	} while (pud++, addr = next, addr != end);
+}
+
+static void __init kasan_populate_pgd(pgd_t *pgd, unsigned long addr,
+				      unsigned long end, int nid)
+{
+	void *p;
+	p4d_t *p4d;
+	unsigned long next;
+
+	if (pgd_none(*pgd)) {
+		p = early_alloc(PAGE_SIZE, nid, true);
+		pgd_populate(&init_mm, pgd, p);
+	}
+
+	p4d = p4d_offset(pgd, addr);
+	do {
+		next = p4d_addr_end(addr, end);
+		kasan_populate_p4d(p4d, addr, next, nid);
+	} while (p4d++, addr = next, addr != end);
+}
+
+static void __init kasan_populate_shadow(unsigned long addr, unsigned long end,
+					 int nid)
+{
+	pgd_t *pgd;
+	unsigned long next;
+
+	addr = addr & PAGE_MASK;
+	end = round_up(end, PAGE_SIZE);
+	pgd = pgd_offset_k(addr);
+	do {
+		next = pgd_addr_end(addr, end);
+		kasan_populate_pgd(pgd, addr, next, nid);
+	} while (pgd++, addr = next, addr != end);
+}
+
+static void __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));
+
+	kasan_populate_shadow(start, end, early_pfn_to_nid(range->start));
+}
+
+static void __init clear_pgds(unsigned long start,
+			unsigned long end)
+{
+	pgd_t *pgd;
+	/* See comment in kasan_init() */
+	unsigned long pgd_end = end & PGDIR_MASK;
+
+	for (; start < pgd_end; start += PGDIR_SIZE) {
+		pgd = pgd_offset_k(start);
+		/*
+		 * With folded p4d, pgd_clear() is nop, use p4d_clear()
+		 * instead.
+		 */
+		if (pgtable_l5_enabled())
+			pgd_clear(pgd);
+		else
+			p4d_clear(p4d_offset(pgd, start));
+	}
+
+	pgd = pgd_offset_k(start);
+	for (; start < end; start += P4D_SIZE)
+		p4d_clear(p4d_offset(pgd, start));
+}
+
+static inline p4d_t *early_p4d_offset(pgd_t *pgd, unsigned long addr)
+{
+	unsigned long p4d;
+
+	if (!pgtable_l5_enabled())
+		return (p4d_t *)pgd;
+
+	p4d = pgd_val(*pgd) & PTE_PFN_MASK;
+	p4d += __START_KERNEL_map - phys_base;
+	return (p4d_t *)p4d + p4d_index(addr);
+}
+
+static void __init kasan_early_p4d_populate(pgd_t *pgd,
+		unsigned long addr,
+		unsigned long end)
+{
+	pgd_t pgd_entry;
+	p4d_t *p4d, p4d_entry;
+	unsigned long next;
+
+	if (pgd_none(*pgd)) {
+		pgd_entry = __pgd(_KERNPG_TABLE |
+					__pa_nodebug(kasan_early_shadow_p4d));
+		set_pgd(pgd, pgd_entry);
+	}
+
+	p4d = early_p4d_offset(pgd, addr);
+	do {
+		next = p4d_addr_end(addr, end);
+
+		if (!p4d_none(*p4d))
+			continue;
+
+		p4d_entry = __p4d(_KERNPG_TABLE |
+					__pa_nodebug(kasan_early_shadow_pud));
+		set_p4d(p4d, p4d_entry);
+	} while (p4d++, addr = next, addr != end && p4d_none(*p4d));
+}
+
+static void __init kasan_map_early_shadow(pgd_t *pgd)
+{
+	/* See comment in kasan_init() */
+	unsigned long addr = KASAN_SHADOW_START & PGDIR_MASK;
+	unsigned long end = KASAN_SHADOW_END;
+	unsigned long next;
+
+	pgd += pgd_index(addr);
+	do {
+		next = pgd_addr_end(addr, end);
+		kasan_early_p4d_populate(pgd, addr, next);
+	} while (pgd++, addr = next, addr != end);
+}
+
+static void __init kasan_shallow_populate_p4ds(pgd_t *pgd,
+					       unsigned long addr,
+					       unsigned long end)
+{
+	p4d_t *p4d;
+	unsigned long next;
+	void *p;
+
+	p4d = p4d_offset(pgd, addr);
+	do {
+		next = p4d_addr_end(addr, end);
+
+		if (p4d_none(*p4d)) {
+			p = early_alloc(PAGE_SIZE, NUMA_NO_NODE, true);
+			p4d_populate(&init_mm, p4d, p);
+		}
+	} while (p4d++, addr = next, addr != end);
+}
+
+static void __init kasan_shallow_populate_pgds(void *start, void *end)
+{
+	unsigned long addr, next;
+	pgd_t *pgd;
+	void *p;
+
+	addr = (unsigned long)start;
+	pgd = pgd_offset_k(addr);
+	do {
+		next = pgd_addr_end(addr, (unsigned long)end);
+
+		if (pgd_none(*pgd)) {
+			p = early_alloc(PAGE_SIZE, NUMA_NO_NODE, true);
+			pgd_populate(&init_mm, pgd, p);
+		}
+
+		/*
+		 * we need to populate p4ds to be synced when running in
+		 * four level mode - see sync_global_pgds_l4()
+		 */
+		kasan_shallow_populate_p4ds(pgd, addr, next);
+	} while (pgd++, addr = next, addr != (unsigned long)end);
+}
+
+void __init kasan_early_init(void)
+{
+	int i;
+	pteval_t pte_val = __pa_nodebug(kasan_early_shadow_page) |
+				__PAGE_KERNEL | _PAGE_ENC;
+	pmdval_t pmd_val = __pa_nodebug(kasan_early_shadow_pte) | _KERNPG_TABLE;
+	pudval_t pud_val = __pa_nodebug(kasan_early_shadow_pmd) | _KERNPG_TABLE;
+	p4dval_t p4d_val = __pa_nodebug(kasan_early_shadow_pud) | _KERNPG_TABLE;
+
+	/* Mask out unsupported __PAGE_KERNEL bits: */
+	pte_val &= __default_kernel_pte_mask;
+	pmd_val &= __default_kernel_pte_mask;
+	pud_val &= __default_kernel_pte_mask;
+	p4d_val &= __default_kernel_pte_mask;
+
+	for (i = 0; i < PTRS_PER_PTE; i++)
+		kasan_early_shadow_pte[i] = __pte(pte_val);
+
+	for (i = 0; i < PTRS_PER_PMD; i++)
+		kasan_early_shadow_pmd[i] = __pmd(pmd_val);
+
+	for (i = 0; i < PTRS_PER_PUD; i++)
+		kasan_early_shadow_pud[i] = __pud(pud_val);
+
+	for (i = 0; pgtable_l5_enabled() && i < PTRS_PER_P4D; i++)
+		kasan_early_shadow_p4d[i] = __p4d(p4d_val);
+
+	kasan_map_early_shadow(early_top_pgt);
+	kasan_map_early_shadow(init_top_pgt);
+}
+
+void __init kasan_init(void)
+{
+	int i;
+	void *shadow_cpu_entry_begin, *shadow_cpu_entry_end;
+
+	memcpy(early_top_pgt, init_top_pgt, sizeof(early_top_pgt));
+
+	/*
+	 * We use the same shadow offset for 4- and 5-level paging to
+	 * facilitate boot-time switching between paging modes.
+	 * As result in 5-level paging mode KASAN_SHADOW_START and
+	 * KASAN_SHADOW_END are not aligned to PGD boundary.
+	 *
+	 * KASAN_SHADOW_START doesn't share PGD with anything else.
+	 * We claim whole PGD entry to make things easier.
+	 *
+	 * KASAN_SHADOW_END lands in the last PGD entry and it collides with
+	 * bunch of things like kernel code, modules, EFI mapping, etc.
+	 * We need to take extra steps to not overwrite them.
+	 */
+	if (pgtable_l5_enabled()) {
+		void *ptr;
+
+		ptr = (void *)pgd_page_vaddr(*pgd_offset_k(KASAN_SHADOW_END));
+		memcpy(tmp_p4d_table, (void *)ptr, sizeof(tmp_p4d_table));
+		set_pgd(&early_top_pgt[pgd_index(KASAN_SHADOW_END)],
+				__pgd(__pa(tmp_p4d_table) | _KERNPG_TABLE));
+	}
+
+	load_cr3(early_top_pgt);
+	__flush_tlb_all();
+
+	clear_pgds(KASAN_SHADOW_START & PGDIR_MASK, KASAN_SHADOW_END);
+
+	kasan_populate_early_shadow((void *)(KASAN_SHADOW_START & PGDIR_MASK),
+			kasan_mem_to_shadow((void *)PAGE_OFFSET));
+
+	for (i = 0; i < E820_MAX_ENTRIES; i++) {
+		if (pfn_mapped[i].end == 0)
+			break;
+
+		map_range(&pfn_mapped[i]);
+	}
+
+	shadow_cpu_entry_begin = (void *)CPU_ENTRY_AREA_BASE;
+	shadow_cpu_entry_begin = kasan_mem_to_shadow(shadow_cpu_entry_begin);
+	shadow_cpu_entry_begin = (void *)round_down(
+			(unsigned long)shadow_cpu_entry_begin, PAGE_SIZE);
+
+	shadow_cpu_entry_end = (void *)(CPU_ENTRY_AREA_BASE +
+					CPU_ENTRY_AREA_MAP_SIZE);
+	shadow_cpu_entry_end = kasan_mem_to_shadow(shadow_cpu_entry_end);
+	shadow_cpu_entry_end = (void *)round_up(
+			(unsigned long)shadow_cpu_entry_end, PAGE_SIZE);
+
+	kasan_populate_early_shadow(
+		kasan_mem_to_shadow((void *)PAGE_OFFSET + MAXMEM),
+		kasan_mem_to_shadow((void *)VMALLOC_START));
+
+	/*
+	 * If we're in full vmalloc mode, don't back vmalloc space with early
+	 * shadow pages. Instead, prepopulate pgds/p4ds so they are synced to
+	 * the global table and we can populate the lower levels on demand.
+	 */
+	if (IS_ENABLED(CONFIG_KASAN_VMALLOC))
+		kasan_shallow_populate_pgds(
+			kasan_mem_to_shadow((void *)VMALLOC_START),
+			kasan_mem_to_shadow((void *)VMALLOC_END));
+	else
+		kasan_populate_early_shadow(
+			kasan_mem_to_shadow((void *)VMALLOC_START),
+			kasan_mem_to_shadow((void *)VMALLOC_END));
+
+	kasan_populate_early_shadow(
+		kasan_mem_to_shadow((void *)VMALLOC_END + 1),
+		shadow_cpu_entry_begin);
+
+	kasan_populate_shadow((unsigned long)shadow_cpu_entry_begin,
+			      (unsigned long)shadow_cpu_entry_end, 0);
+
+	kasan_populate_early_shadow(shadow_cpu_entry_end,
+			kasan_mem_to_shadow((void *)__START_KERNEL_map));
+
+	kasan_populate_shadow((unsigned long)kasan_mem_to_shadow(_stext),
+			      (unsigned long)kasan_mem_to_shadow(_end),
+			      early_pfn_to_nid(__pa(_stext)));
+
+	kasan_populate_early_shadow(kasan_mem_to_shadow((void *)MODULES_END),
+					(void *)KASAN_SHADOW_END);
+
+	load_cr3(init_top_pgt);
+	__flush_tlb_all();
+
+	/*
+	 * kasan_early_shadow_page has been used as early shadow memory, thus
+	 * it may contain some garbage. Now we can clear and write protect it,
+	 * since after the TLB flush no one should write to it.
+	 */
+	memset(kasan_early_shadow_page, 0, PAGE_SIZE);
+	for (i = 0; i < PTRS_PER_PTE; i++) {
+		pte_t pte;
+		pgprot_t prot;
+
+		prot = __pgprot(__PAGE_KERNEL_RO | _PAGE_ENC);
+		pgprot_val(prot) &= __default_kernel_pte_mask;
+
+		pte = __pte(__pa(kasan_early_shadow_page) | pgprot_val(prot));
+		set_pte(&kasan_early_shadow_pte[i], pte);
+	}
+	/* Flush TLBs again to be sure that write protection applied. */
+	__flush_tlb_all();
+
+	init_task.kasan_depth = 0;
+	pr_info("KernelAddressSanitizer initialized\n");
+}