413 lines
12 KiB
C
413 lines
12 KiB
C
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// SPDX-License-Identifier: GPL-2.0-only
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/*
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* This file contains kasan initialization code for ARM64.
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*
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* Copyright (c) 2015 Samsung Electronics Co., Ltd.
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* Author: Andrey Ryabinin <ryabinin.a.a@gmail.com>
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*/
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#define pr_fmt(fmt) "kasan: " fmt
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#include <linux/kasan.h>
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#include <linux/kernel.h>
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#include <linux/sched/task.h>
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#include <linux/memblock.h>
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#include <linux/start_kernel.h>
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#include <linux/mm.h>
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#include <asm/mmu_context.h>
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#include <asm/kernel-pgtable.h>
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#include <asm/page.h>
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#include <asm/pgalloc.h>
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#include <asm/sections.h>
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#include <asm/tlbflush.h>
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#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
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static pgd_t tmp_pg_dir[PTRS_PER_PTE] __initdata __aligned(PAGE_SIZE);
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/*
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* The p*d_populate functions call virt_to_phys implicitly so they can't be used
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* directly on kernel symbols (bm_p*d). All the early functions are called too
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* early to use lm_alias so __p*d_populate functions must be used to populate
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* with the physical address from __pa_symbol.
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*/
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static phys_addr_t __init kasan_alloc_zeroed_page(int node)
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{
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void *p = memblock_alloc_try_nid(PAGE_SIZE, PAGE_SIZE,
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__pa(MAX_DMA_ADDRESS),
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MEMBLOCK_ALLOC_NOLEAKTRACE, node);
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if (!p)
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panic("%s: Failed to allocate %lu bytes align=0x%lx nid=%d from=%llx\n",
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__func__, PAGE_SIZE, PAGE_SIZE, node,
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__pa(MAX_DMA_ADDRESS));
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return __pa(p);
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}
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static phys_addr_t __init kasan_alloc_raw_page(int node)
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{
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void *p = memblock_alloc_try_nid_raw(PAGE_SIZE, PAGE_SIZE,
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__pa(MAX_DMA_ADDRESS),
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MEMBLOCK_ALLOC_NOLEAKTRACE,
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node);
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if (!p)
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panic("%s: Failed to allocate %lu bytes align=0x%lx nid=%d from=%llx\n",
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__func__, PAGE_SIZE, PAGE_SIZE, node,
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__pa(MAX_DMA_ADDRESS));
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return __pa(p);
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}
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static pte_t *__init kasan_pte_offset(pmd_t *pmdp, unsigned long addr, int node,
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bool early)
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{
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if (pmd_none(READ_ONCE(*pmdp))) {
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phys_addr_t pte_phys = early ?
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__pa_symbol(kasan_early_shadow_pte)
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: kasan_alloc_zeroed_page(node);
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__pmd_populate(pmdp, pte_phys, PMD_TYPE_TABLE);
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}
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return early ? pte_offset_kimg(pmdp, addr)
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: pte_offset_kernel(pmdp, addr);
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}
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static pmd_t *__init kasan_pmd_offset(pud_t *pudp, unsigned long addr, int node,
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bool early)
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{
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if (pud_none(READ_ONCE(*pudp))) {
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phys_addr_t pmd_phys = early ?
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__pa_symbol(kasan_early_shadow_pmd)
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: kasan_alloc_zeroed_page(node);
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__pud_populate(pudp, pmd_phys, PUD_TYPE_TABLE);
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}
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return early ? pmd_offset_kimg(pudp, addr) : pmd_offset(pudp, addr);
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}
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static pud_t *__init kasan_pud_offset(p4d_t *p4dp, unsigned long addr, int node,
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bool early)
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{
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if (p4d_none(READ_ONCE(*p4dp))) {
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phys_addr_t pud_phys = early ?
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__pa_symbol(kasan_early_shadow_pud)
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: kasan_alloc_zeroed_page(node);
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__p4d_populate(p4dp, pud_phys, P4D_TYPE_TABLE);
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}
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return early ? pud_offset_kimg(p4dp, addr) : pud_offset(p4dp, addr);
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}
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static p4d_t *__init kasan_p4d_offset(pgd_t *pgdp, unsigned long addr, int node,
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bool early)
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{
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if (pgd_none(READ_ONCE(*pgdp))) {
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phys_addr_t p4d_phys = early ?
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__pa_symbol(kasan_early_shadow_p4d)
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: kasan_alloc_zeroed_page(node);
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__pgd_populate(pgdp, p4d_phys, PGD_TYPE_TABLE);
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}
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return early ? p4d_offset_kimg(pgdp, addr) : p4d_offset(pgdp, addr);
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}
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static void __init kasan_pte_populate(pmd_t *pmdp, unsigned long addr,
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unsigned long end, int node, bool early)
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{
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unsigned long next;
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pte_t *ptep = kasan_pte_offset(pmdp, addr, node, early);
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do {
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phys_addr_t page_phys = early ?
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__pa_symbol(kasan_early_shadow_page)
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: kasan_alloc_raw_page(node);
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if (!early)
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memset(__va(page_phys), KASAN_SHADOW_INIT, PAGE_SIZE);
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next = addr + PAGE_SIZE;
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__set_pte(ptep, pfn_pte(__phys_to_pfn(page_phys), PAGE_KERNEL));
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} while (ptep++, addr = next, addr != end && pte_none(__ptep_get(ptep)));
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}
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static void __init kasan_pmd_populate(pud_t *pudp, unsigned long addr,
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unsigned long end, int node, bool early)
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{
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unsigned long next;
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pmd_t *pmdp = kasan_pmd_offset(pudp, addr, node, early);
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do {
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next = pmd_addr_end(addr, end);
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kasan_pte_populate(pmdp, addr, next, node, early);
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} while (pmdp++, addr = next, addr != end && pmd_none(READ_ONCE(*pmdp)));
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}
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static void __init kasan_pud_populate(p4d_t *p4dp, unsigned long addr,
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unsigned long end, int node, bool early)
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{
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unsigned long next;
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pud_t *pudp = kasan_pud_offset(p4dp, addr, node, early);
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do {
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next = pud_addr_end(addr, end);
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kasan_pmd_populate(pudp, addr, next, node, early);
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} while (pudp++, addr = next, addr != end && pud_none(READ_ONCE(*pudp)));
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}
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static void __init kasan_p4d_populate(pgd_t *pgdp, unsigned long addr,
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unsigned long end, int node, bool early)
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{
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unsigned long next;
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p4d_t *p4dp = kasan_p4d_offset(pgdp, addr, node, early);
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do {
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next = p4d_addr_end(addr, end);
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kasan_pud_populate(p4dp, addr, next, node, early);
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} while (p4dp++, addr = next, addr != end && p4d_none(READ_ONCE(*p4dp)));
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}
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static void __init kasan_pgd_populate(unsigned long addr, unsigned long end,
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int node, bool early)
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{
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unsigned long next;
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pgd_t *pgdp;
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pgdp = pgd_offset_k(addr);
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do {
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next = pgd_addr_end(addr, end);
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kasan_p4d_populate(pgdp, addr, next, node, early);
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} while (pgdp++, addr = next, addr != end);
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}
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#if defined(CONFIG_ARM64_64K_PAGES) || CONFIG_PGTABLE_LEVELS > 4
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#define SHADOW_ALIGN P4D_SIZE
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#else
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#define SHADOW_ALIGN PUD_SIZE
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#endif
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/*
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* Return whether 'addr' is aligned to the size covered by a root level
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* descriptor.
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*/
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static bool __init root_level_aligned(u64 addr)
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{
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int shift = (ARM64_HW_PGTABLE_LEVELS(vabits_actual) - 1) * (PAGE_SHIFT - 3);
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return (addr % (PAGE_SIZE << shift)) == 0;
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}
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/* The early shadow maps everything to a single page of zeroes */
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asmlinkage void __init kasan_early_init(void)
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{
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BUILD_BUG_ON(KASAN_SHADOW_OFFSET !=
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KASAN_SHADOW_END - (1UL << (64 - KASAN_SHADOW_SCALE_SHIFT)));
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BUILD_BUG_ON(!IS_ALIGNED(_KASAN_SHADOW_START(VA_BITS), SHADOW_ALIGN));
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BUILD_BUG_ON(!IS_ALIGNED(_KASAN_SHADOW_START(VA_BITS_MIN), SHADOW_ALIGN));
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BUILD_BUG_ON(!IS_ALIGNED(KASAN_SHADOW_END, SHADOW_ALIGN));
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if (!root_level_aligned(KASAN_SHADOW_START)) {
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/*
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* The start address is misaligned, and so the next level table
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* will be shared with the linear region. This can happen with
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* 4 or 5 level paging, so install a generic pte_t[] as the
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* next level. This prevents the kasan_pgd_populate call below
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* from inserting an entry that refers to the shared KASAN zero
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* shadow pud_t[]/p4d_t[], which could end up getting corrupted
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* when the linear region is mapped.
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*/
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static pte_t tbl[PTRS_PER_PTE] __page_aligned_bss;
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pgd_t *pgdp = pgd_offset_k(KASAN_SHADOW_START);
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set_pgd(pgdp, __pgd(__pa_symbol(tbl) | PGD_TYPE_TABLE));
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}
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kasan_pgd_populate(KASAN_SHADOW_START, KASAN_SHADOW_END, NUMA_NO_NODE,
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true);
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}
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/* Set up full kasan mappings, ensuring that the mapped pages are zeroed */
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static void __init kasan_map_populate(unsigned long start, unsigned long end,
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int node)
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{
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kasan_pgd_populate(start & PAGE_MASK, PAGE_ALIGN(end), node, false);
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}
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/*
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* Return the descriptor index of 'addr' in the root level table
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*/
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static int __init root_level_idx(u64 addr)
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{
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/*
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* On 64k pages, the TTBR1 range root tables are extended for 52-bit
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* virtual addressing, and TTBR1 will simply point to the pgd_t entry
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* that covers the start of the 48-bit addressable VA space if LVA is
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* not implemented. This means we need to index the table as usual,
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* instead of masking off bits based on vabits_actual.
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*/
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u64 vabits = IS_ENABLED(CONFIG_ARM64_64K_PAGES) ? VA_BITS
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: vabits_actual;
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int shift = (ARM64_HW_PGTABLE_LEVELS(vabits) - 1) * (PAGE_SHIFT - 3);
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return (addr & ~_PAGE_OFFSET(vabits)) >> (shift + PAGE_SHIFT);
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}
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/*
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* Clone a next level table from swapper_pg_dir into tmp_pg_dir
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*/
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static void __init clone_next_level(u64 addr, pgd_t *tmp_pg_dir, pud_t *pud)
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{
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int idx = root_level_idx(addr);
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pgd_t pgd = READ_ONCE(swapper_pg_dir[idx]);
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pud_t *pudp = (pud_t *)__phys_to_kimg(__pgd_to_phys(pgd));
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memcpy(pud, pudp, PAGE_SIZE);
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tmp_pg_dir[idx] = __pgd(__phys_to_pgd_val(__pa_symbol(pud)) |
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PUD_TYPE_TABLE);
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}
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/*
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* Return the descriptor index of 'addr' in the next level table
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*/
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static int __init next_level_idx(u64 addr)
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{
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int shift = (ARM64_HW_PGTABLE_LEVELS(vabits_actual) - 2) * (PAGE_SHIFT - 3);
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return (addr >> (shift + PAGE_SHIFT)) % PTRS_PER_PTE;
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}
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/*
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* Dereference the table descriptor at 'pgd_idx' and clear the entries from
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* 'start' to 'end' (exclusive) from the table.
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*/
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static void __init clear_next_level(int pgd_idx, int start, int end)
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{
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pgd_t pgd = READ_ONCE(swapper_pg_dir[pgd_idx]);
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pud_t *pudp = (pud_t *)__phys_to_kimg(__pgd_to_phys(pgd));
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memset(&pudp[start], 0, (end - start) * sizeof(pud_t));
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}
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static void __init clear_shadow(u64 start, u64 end)
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{
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int l = root_level_idx(start), m = root_level_idx(end);
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if (!root_level_aligned(start))
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clear_next_level(l++, next_level_idx(start), PTRS_PER_PTE);
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if (!root_level_aligned(end))
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clear_next_level(m, 0, next_level_idx(end));
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memset(&swapper_pg_dir[l], 0, (m - l) * sizeof(pgd_t));
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}
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static void __init kasan_init_shadow(void)
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{
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static pud_t pud[2][PTRS_PER_PUD] __initdata __aligned(PAGE_SIZE);
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u64 kimg_shadow_start, kimg_shadow_end;
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u64 mod_shadow_start;
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u64 vmalloc_shadow_end;
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phys_addr_t pa_start, pa_end;
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u64 i;
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kimg_shadow_start = (u64)kasan_mem_to_shadow(KERNEL_START) & PAGE_MASK;
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kimg_shadow_end = PAGE_ALIGN((u64)kasan_mem_to_shadow(KERNEL_END));
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mod_shadow_start = (u64)kasan_mem_to_shadow((void *)MODULES_VADDR);
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vmalloc_shadow_end = (u64)kasan_mem_to_shadow((void *)VMALLOC_END);
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/*
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* We are going to perform proper setup of shadow memory.
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* At first we should unmap early shadow (clear_pgds() call below).
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* However, instrumented code couldn't execute without shadow memory.
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* tmp_pg_dir used to keep early shadow mapped until full shadow
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* setup will be finished.
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*/
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memcpy(tmp_pg_dir, swapper_pg_dir, sizeof(tmp_pg_dir));
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/*
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* If the start or end address of the shadow region is not aligned to
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* the root level size, we have to allocate a temporary next-level table
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* in each case, clone the next level of descriptors, and install the
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* table into tmp_pg_dir. Note that with 5 levels of paging, the next
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* level will in fact be p4d_t, but that makes no difference in this
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* case.
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*/
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if (!root_level_aligned(KASAN_SHADOW_START))
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||
|
|
clone_next_level(KASAN_SHADOW_START, tmp_pg_dir, pud[0]);
|
||
|
|
if (!root_level_aligned(KASAN_SHADOW_END))
|
||
|
|
clone_next_level(KASAN_SHADOW_END, tmp_pg_dir, pud[1]);
|
||
|
|
dsb(ishst);
|
||
|
|
cpu_replace_ttbr1(lm_alias(tmp_pg_dir));
|
||
|
|
|
||
|
|
clear_shadow(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);
|
||
|
|
|
||
|
|
BUILD_BUG_ON(VMALLOC_START != MODULES_END);
|
||
|
|
kasan_populate_early_shadow((void *)vmalloc_shadow_end,
|
||
|
|
(void *)KASAN_SHADOW_END);
|
||
|
|
|
||
|
|
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));
|
||
|
|
}
|
||
|
|
|
||
|
|
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)
|
||
|
|
/*
|
||
|
|
* Generic KASAN is now fully initialized.
|
||
|
|
* Software and Hardware Tag-Based modes still require
|
||
|
|
* kasan_init_sw_tags() and kasan_init_hw_tags() correspondingly.
|
||
|
|
*/
|
||
|
|
pr_info("KernelAddressSanitizer initialized (generic)\n");
|
||
|
|
#endif
|
||
|
|
}
|
||
|
|
|
||
|
|
#endif /* CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS */
|