Loading...
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 | /*
* 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/bootmem.h>
#include <linux/init.h>
#include <linux/kasan.h>
#include <linux/kernel.h>
#include <linux/memblock.h>
#include <linux/pfn.h>
#include <asm/page.h>
#include <asm/pgalloc.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 > 3
pud_t kasan_zero_pud[PTRS_PER_PUD] __page_aligned_bss;
#endif
#if CONFIG_PGTABLE_LEVELS > 2
pmd_t kasan_zero_pmd[PTRS_PER_PMD] __page_aligned_bss;
#endif
pte_t kasan_zero_pte[PTRS_PER_PTE] __page_aligned_bss;
static __init void *early_alloc(size_t size, int node)
{
return memblock_virt_alloc_try_nid(size, size, __pa(MAX_DMA_ADDRESS),
BOOTMEM_ALLOC_ACCESSIBLE, node);
}
static void __init 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(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 void __init 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, kasan_zero_pte);
continue;
}
if (pmd_none(*pmd)) {
pmd_populate_kernel(&init_mm, pmd,
early_alloc(PAGE_SIZE, NUMA_NO_NODE));
}
zero_pte_populate(pmd, addr, next);
} while (pmd++, addr = next, addr != end);
}
static void __init zero_pud_populate(pgd_t *pgd, unsigned long addr,
unsigned long end)
{
pud_t *pud = pud_offset(pgd, 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, kasan_zero_pmd);
pmd = pmd_offset(pud, addr);
pmd_populate_kernel(&init_mm, pmd, kasan_zero_pte);
continue;
}
if (pud_none(*pud)) {
pud_populate(&init_mm, pud,
early_alloc(PAGE_SIZE, NUMA_NO_NODE));
}
zero_pmd_populate(pud, addr, next);
} while (pud++, addr = next, addr != end);
}
/**
* 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
*/
void __init 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) {
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.
*/
pgd_populate(&init_mm, pgd, kasan_zero_pud);
pud = pud_offset(pgd, addr);
pud_populate(&init_mm, pud, kasan_zero_pmd);
pmd = pmd_offset(pud, addr);
pmd_populate_kernel(&init_mm, pmd, kasan_zero_pte);
continue;
}
if (pgd_none(*pgd)) {
pgd_populate(&init_mm, pgd,
early_alloc(PAGE_SIZE, NUMA_NO_NODE));
}
zero_pud_populate(pgd, addr, next);
} while (pgd++, addr = next, addr != end);
}
|