kasan: rename source files to reflect the new naming scheme

We now have two KASAN modes: generic KASAN and tag-based KASAN.  Rename
kasan.c to generic.c to reflect that.  Also rename kasan_init.c to init.c
as it contains initialization code for both KASAN modes.

Link: http://lkml.kernel.org/r/88c6fd2a883e459e6242030497230e5fb0d44d44.1544099024.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 488 insertions, 0 deletions

diff --git a/mm/kasan/init.c b/mm/kasan/init.c
new file mode 100644
index 000000000000..c7550eb65922
--- /dev/null
+++ b/mm/kasan/init.c
@@ -0,0 +1,488 @@
+/*
+ * This file contains some kasan initialization code.
+ *
+ * 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.
+ *
+ */
+
+#include <linux/memblock.h>
+#include <linux/init.h>
+#include <linux/kasan.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/pfn.h>
+#include <linux/slab.h>
+
+#include <asm/page.h>
+#include <asm/pgalloc.h>
+
+#include "kasan.h"
+
+/*
+ * This page serves two purposes:
+ *   - It used as early shadow memory. The entire shadow region populated
+ *     with this page, before we will be able to setup normal shadow memory.
+ *   - Latter it reused it as zero shadow to cover large ranges of memory
+ *     that allowed to access, but not handled by kasan (vmalloc/vmemmap ...).
+ */
+unsigned char kasan_zero_page[PAGE_SIZE] __page_aligned_bss;
+
+#if CONFIG_PGTABLE_LEVELS > 4
+p4d_t kasan_zero_p4d[MAX_PTRS_PER_P4D] __page_aligned_bss;
+static inline bool kasan_p4d_table(pgd_t pgd)
+{
+	return pgd_page(pgd) == virt_to_page(lm_alias(kasan_zero_p4d));
+}
+#else
+static inline bool kasan_p4d_table(pgd_t pgd)
+{
+	return 0;
+}
+#endif
+#if CONFIG_PGTABLE_LEVELS > 3
+pud_t kasan_zero_pud[PTRS_PER_PUD] __page_aligned_bss;
+static inline bool kasan_pud_table(p4d_t p4d)
+{
+	return p4d_page(p4d) == virt_to_page(lm_alias(kasan_zero_pud));
+}
+#else
+static inline bool kasan_pud_table(p4d_t p4d)
+{
+	return 0;
+}
+#endif
+#if CONFIG_PGTABLE_LEVELS > 2
+pmd_t kasan_zero_pmd[PTRS_PER_PMD] __page_aligned_bss;
+static inline bool kasan_pmd_table(pud_t pud)
+{
+	return pud_page(pud) == virt_to_page(lm_alias(kasan_zero_pmd));
+}
+#else
+static inline bool kasan_pmd_table(pud_t pud)
+{
+	return 0;
+}
+#endif
+pte_t kasan_zero_pte[PTRS_PER_PTE] __page_aligned_bss;
+
+static inline bool kasan_pte_table(pmd_t pmd)
+{
+	return pmd_page(pmd) == virt_to_page(lm_alias(kasan_zero_pte));
+}
+
+static inline bool kasan_zero_page_entry(pte_t pte)
+{
+	return pte_page(pte) == virt_to_page(lm_alias(kasan_zero_page));
+}
+
+static __init void *early_alloc(size_t size, int node)
+{
+	return memblock_alloc_try_nid(size, size, __pa(MAX_DMA_ADDRESS),
+					MEMBLOCK_ALLOC_ACCESSIBLE, node);
+}
+
+static void __ref zero_pte_populate(pmd_t *pmd, unsigned long addr,
+				unsigned long end)
+{
+	pte_t *pte = pte_offset_kernel(pmd, addr);
+	pte_t zero_pte;
+
+	zero_pte = pfn_pte(PFN_DOWN(__pa_symbol(kasan_zero_page)), PAGE_KERNEL);
+	zero_pte = pte_wrprotect(zero_pte);
+
+	while (addr + PAGE_SIZE <= end) {
+		set_pte_at(&init_mm, addr, pte, zero_pte);
+		addr += PAGE_SIZE;
+		pte = pte_offset_kernel(pmd, addr);
+	}
+}
+
+static int __ref zero_pmd_populate(pud_t *pud, unsigned long addr,
+				unsigned long end)
+{
+	pmd_t *pmd = pmd_offset(pud, addr);
+	unsigned long next;
+
+	do {
+		next = pmd_addr_end(addr, end);
+
+		if (IS_ALIGNED(addr, PMD_SIZE) && end - addr >= PMD_SIZE) {
+			pmd_populate_kernel(&init_mm, pmd, lm_alias(kasan_zero_pte));
+			continue;
+		}
+
+		if (pmd_none(*pmd)) {
+			pte_t *p;
+
+			if (slab_is_available())
+				p = pte_alloc_one_kernel(&init_mm, addr);
+			else
+				p = early_alloc(PAGE_SIZE, NUMA_NO_NODE);
+			if (!p)
+				return -ENOMEM;
+
+			pmd_populate_kernel(&init_mm, pmd, p);
+		}
+		zero_pte_populate(pmd, addr, next);
+	} while (pmd++, addr = next, addr != end);
+
+	return 0;
+}
+
+static int __ref zero_pud_populate(p4d_t *p4d, unsigned long addr,
+				unsigned long end)
+{
+	pud_t *pud = pud_offset(p4d, addr);
+	unsigned long next;
+
+	do {
+		next = pud_addr_end(addr, end);
+		if (IS_ALIGNED(addr, PUD_SIZE) && end - addr >= PUD_SIZE) {
+			pmd_t *pmd;
+
+			pud_populate(&init_mm, pud, lm_alias(kasan_zero_pmd));
+			pmd = pmd_offset(pud, addr);
+			pmd_populate_kernel(&init_mm, pmd, lm_alias(kasan_zero_pte));
+			continue;
+		}
+
+		if (pud_none(*pud)) {
+			pmd_t *p;
+
+			if (slab_is_available()) {
+				p = pmd_alloc(&init_mm, pud, addr);
+				if (!p)
+					return -ENOMEM;
+			} else {
+				pud_populate(&init_mm, pud,
+					early_alloc(PAGE_SIZE, NUMA_NO_NODE));
+			}
+		}
+		zero_pmd_populate(pud, addr, next);
+	} while (pud++, addr = next, addr != end);
+
+	return 0;
+}
+
+static int __ref zero_p4d_populate(pgd_t *pgd, unsigned long addr,
+				unsigned long end)
+{
+	p4d_t *p4d = p4d_offset(pgd, addr);
+	unsigned long next;
+
+	do {
+		next = p4d_addr_end(addr, end);
+		if (IS_ALIGNED(addr, P4D_SIZE) && end - addr >= P4D_SIZE) {
+			pud_t *pud;
+			pmd_t *pmd;
+
+			p4d_populate(&init_mm, p4d, lm_alias(kasan_zero_pud));
+			pud = pud_offset(p4d, addr);
+			pud_populate(&init_mm, pud, lm_alias(kasan_zero_pmd));
+			pmd = pmd_offset(pud, addr);
+			pmd_populate_kernel(&init_mm, pmd,
+						lm_alias(kasan_zero_pte));
+			continue;
+		}
+
+		if (p4d_none(*p4d)) {
+			pud_t *p;
+
+			if (slab_is_available()) {
+				p = pud_alloc(&init_mm, p4d, addr);
+				if (!p)
+					return -ENOMEM;
+			} else {
+				p4d_populate(&init_mm, p4d,
+					early_alloc(PAGE_SIZE, NUMA_NO_NODE));
+			}
+		}
+		zero_pud_populate(p4d, addr, next);
+	} while (p4d++, addr = next, addr != end);
+
+	return 0;
+}
+
+/**
+ * kasan_populate_zero_shadow - populate shadow memory region with
+ *                               kasan_zero_page
+ * @shadow_start - start of the memory range to populate
+ * @shadow_end   - end of the memory range to populate
+ */
+int __ref kasan_populate_zero_shadow(const void *shadow_start,
+				const void *shadow_end)
+{
+	unsigned long addr = (unsigned long)shadow_start;
+	unsigned long end = (unsigned long)shadow_end;
+	pgd_t *pgd = pgd_offset_k(addr);
+	unsigned long next;
+
+	do {
+		next = pgd_addr_end(addr, end);
+
+		if (IS_ALIGNED(addr, PGDIR_SIZE) && end - addr >= PGDIR_SIZE) {
+			p4d_t *p4d;
+			pud_t *pud;
+			pmd_t *pmd;
+
+			/*
+			 * kasan_zero_pud should be populated with pmds
+			 * at this moment.
+			 * [pud,pmd]_populate*() below needed only for
+			 * 3,2 - level page tables where we don't have
+			 * puds,pmds, so pgd_populate(), pud_populate()
+			 * is noops.
+			 *
+			 * The ifndef is required to avoid build breakage.
+			 *
+			 * With 5level-fixup.h, pgd_populate() is not nop and
+			 * we reference kasan_zero_p4d. It's not defined
+			 * unless 5-level paging enabled.
+			 *
+			 * The ifndef can be dropped once all KASAN-enabled
+			 * architectures will switch to pgtable-nop4d.h.
+			 */
+#ifndef __ARCH_HAS_5LEVEL_HACK
+			pgd_populate(&init_mm, pgd, lm_alias(kasan_zero_p4d));
+#endif
+			p4d = p4d_offset(pgd, addr);
+			p4d_populate(&init_mm, p4d, lm_alias(kasan_zero_pud));
+			pud = pud_offset(p4d, addr);
+			pud_populate(&init_mm, pud, lm_alias(kasan_zero_pmd));
+			pmd = pmd_offset(pud, addr);
+			pmd_populate_kernel(&init_mm, pmd, lm_alias(kasan_zero_pte));
+			continue;
+		}
+
+		if (pgd_none(*pgd)) {
+			p4d_t *p;
+
+			if (slab_is_available()) {
+				p = p4d_alloc(&init_mm, pgd, addr);
+				if (!p)
+					return -ENOMEM;
+			} else {
+				pgd_populate(&init_mm, pgd,
+					early_alloc(PAGE_SIZE, NUMA_NO_NODE));
+			}
+		}
+		zero_p4d_populate(pgd, addr, next);
+	} while (pgd++, addr = next, addr != end);
+
+	return 0;
+}
+
+static void kasan_free_pte(pte_t *pte_start, pmd_t *pmd)
+{
+	pte_t *pte;
+	int i;
+
+	for (i = 0; i < PTRS_PER_PTE; i++) {
+		pte = pte_start + i;
+		if (!pte_none(*pte))
+			return;
+	}
+
+	pte_free_kernel(&init_mm, (pte_t *)page_to_virt(pmd_page(*pmd)));
+	pmd_clear(pmd);
+}
+
+static void kasan_free_pmd(pmd_t *pmd_start, pud_t *pud)
+{
+	pmd_t *pmd;
+	int i;
+
+	for (i = 0; i < PTRS_PER_PMD; i++) {
+		pmd = pmd_start + i;
+		if (!pmd_none(*pmd))
+			return;
+	}
+
+	pmd_free(&init_mm, (pmd_t *)page_to_virt(pud_page(*pud)));
+	pud_clear(pud);
+}
+
+static void kasan_free_pud(pud_t *pud_start, p4d_t *p4d)
+{
+	pud_t *pud;
+	int i;
+
+	for (i = 0; i < PTRS_PER_PUD; i++) {
+		pud = pud_start + i;
+		if (!pud_none(*pud))
+			return;
+	}
+
+	pud_free(&init_mm, (pud_t *)page_to_virt(p4d_page(*p4d)));
+	p4d_clear(p4d);
+}
+
+static void kasan_free_p4d(p4d_t *p4d_start, pgd_t *pgd)
+{
+	p4d_t *p4d;
+	int i;
+
+	for (i = 0; i < PTRS_PER_P4D; i++) {
+		p4d = p4d_start + i;
+		if (!p4d_none(*p4d))
+			return;
+	}
+
+	p4d_free(&init_mm, (p4d_t *)page_to_virt(pgd_page(*pgd)));
+	pgd_clear(pgd);
+}
+
+static void kasan_remove_pte_table(pte_t *pte, unsigned long addr,
+				unsigned long end)
+{
+	unsigned long next;
+
+	for (; addr < end; addr = next, pte++) {
+		next = (addr + PAGE_SIZE) & PAGE_MASK;
+		if (next > end)
+			next = end;
+
+		if (!pte_present(*pte))
+			continue;
+
+		if (WARN_ON(!kasan_zero_page_entry(*pte)))
+			continue;
+		pte_clear(&init_mm, addr, pte);
+	}
+}
+
+static void kasan_remove_pmd_table(pmd_t *pmd, unsigned long addr,
+				unsigned long end)
+{
+	unsigned long next;
+
+	for (; addr < end; addr = next, pmd++) {
+		pte_t *pte;
+
+		next = pmd_addr_end(addr, end);
+
+		if (!pmd_present(*pmd))
+			continue;
+
+		if (kasan_pte_table(*pmd)) {
+			if (IS_ALIGNED(addr, PMD_SIZE) &&
+			    IS_ALIGNED(next, PMD_SIZE))
+				pmd_clear(pmd);
+			continue;
+		}
+		pte = pte_offset_kernel(pmd, addr);
+		kasan_remove_pte_table(pte, addr, next);
+		kasan_free_pte(pte_offset_kernel(pmd, 0), pmd);
+	}
+}
+
+static void kasan_remove_pud_table(pud_t *pud, unsigned long addr,
+				unsigned long end)
+{
+	unsigned long next;
+
+	for (; addr < end; addr = next, pud++) {
+		pmd_t *pmd, *pmd_base;
+
+		next = pud_addr_end(addr, end);
+
+		if (!pud_present(*pud))
+			continue;
+
+		if (kasan_pmd_table(*pud)) {
+			if (IS_ALIGNED(addr, PUD_SIZE) &&
+			    IS_ALIGNED(next, PUD_SIZE))
+				pud_clear(pud);
+			continue;
+		}
+		pmd = pmd_offset(pud, addr);
+		pmd_base = pmd_offset(pud, 0);
+		kasan_remove_pmd_table(pmd, addr, next);
+		kasan_free_pmd(pmd_base, pud);
+	}
+}
+
+static void kasan_remove_p4d_table(p4d_t *p4d, unsigned long addr,
+				unsigned long end)
+{
+	unsigned long next;
+
+	for (; addr < end; addr = next, p4d++) {
+		pud_t *pud;
+
+		next = p4d_addr_end(addr, end);
+
+		if (!p4d_present(*p4d))
+			continue;
+
+		if (kasan_pud_table(*p4d)) {
+			if (IS_ALIGNED(addr, P4D_SIZE) &&
+			    IS_ALIGNED(next, P4D_SIZE))
+				p4d_clear(p4d);
+			continue;
+		}
+		pud = pud_offset(p4d, addr);
+		kasan_remove_pud_table(pud, addr, next);
+		kasan_free_pud(pud_offset(p4d, 0), p4d);
+	}
+}
+
+void kasan_remove_zero_shadow(void *start, unsigned long size)
+{
+	unsigned long addr, end, next;
+	pgd_t *pgd;
+
+	addr = (unsigned long)kasan_mem_to_shadow(start);
+	end = addr + (size >> KASAN_SHADOW_SCALE_SHIFT);
+
+	if (WARN_ON((unsigned long)start %
+			(KASAN_SHADOW_SCALE_SIZE * PAGE_SIZE)) ||
+	    WARN_ON(size % (KASAN_SHADOW_SCALE_SIZE * PAGE_SIZE)))
+		return;
+
+	for (; addr < end; addr = next) {
+		p4d_t *p4d;
+
+		next = pgd_addr_end(addr, end);
+
+		pgd = pgd_offset_k(addr);
+		if (!pgd_present(*pgd))
+			continue;
+
+		if (kasan_p4d_table(*pgd)) {
+			if (IS_ALIGNED(addr, PGDIR_SIZE) &&
+			    IS_ALIGNED(next, PGDIR_SIZE))
+				pgd_clear(pgd);
+			continue;
+		}
+
+		p4d = p4d_offset(pgd, addr);
+		kasan_remove_p4d_table(p4d, addr, next);
+		kasan_free_p4d(p4d_offset(pgd, 0), pgd);
+	}
+}
+
+int kasan_add_zero_shadow(void *start, unsigned long size)
+{
+	int ret;
+	void *shadow_start, *shadow_end;
+
+	shadow_start = kasan_mem_to_shadow(start);
+	shadow_end = shadow_start + (size >> KASAN_SHADOW_SCALE_SHIFT);
+
+	if (WARN_ON((unsigned long)start %
+			(KASAN_SHADOW_SCALE_SIZE * PAGE_SIZE)) ||
+	    WARN_ON(size % (KASAN_SHADOW_SCALE_SIZE * PAGE_SIZE)))
+		return -EINVAL;
+
+	ret = kasan_populate_zero_shadow(shadow_start, shadow_end);
+	if (ret)
+		kasan_remove_zero_shadow(shadow_start,
+					size >> KASAN_SHADOW_SCALE_SHIFT);
+	return ret;
+}