219 lines
6.3 KiB
C
219 lines
6.3 KiB
C
|
/*
|
||
|
|
* This file contains kasan initialization code for ARM64.
|
||
|
|
*
|
||
|
|
* 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.
|
||
|
|
*
|
||
|
|
*/
|
||
|
|
|
||
|
|
#define pr_fmt(fmt) "kasan: " fmt
|
||
|
|
#include <linux/kasan.h>
|
||
|
|
#include <linux/kernel.h>
|
||
|
|
#include <linux/memblock.h>
|
||
|
|
#include <linux/start_kernel.h>
|
||
|
|
#include <linux/mm.h>
|
||
|
|
|
||
|
|
#include <asm/mmu_context.h>
|
||
|
|
#include <asm/kernel-pgtable.h>
|
||
|
|
#include <asm/page.h>
|
||
|
|
#include <asm/pgalloc.h>
|
||
|
|
#include <asm/pgtable.h>
|
||
|
|
#include <asm/sections.h>
|
||
|
|
#include <asm/tlbflush.h>
|
||
|
|
|
||
|
|
static pgd_t tmp_pg_dir[PTRS_PER_PGD] __initdata __aligned(PGD_SIZE);
|
||
|
|
|
||
|
|
/*
|
||
|
|
* The p*d_populate functions call virt_to_phys implicitly so they can't be used
|
||
|
|
* directly on kernel symbols (bm_p*d). All the early functions are called too
|
||
|
|
* early to use lm_alias so __p*d_populate functions must be used to populate
|
||
|
|
* with the physical address from __pa_symbol.
|
||
|
|
*/
|
||
|
|
|
||
|
|
static void __init kasan_early_pte_populate(pmd_t *pmd, unsigned long addr,
|
||
|
|
unsigned long end)
|
||
|
|
{
|
||
|
|
pte_t *pte;
|
||
|
|
unsigned long next;
|
||
|
|
|
||
|
|
if (pmd_none(*pmd))
|
||
|
|
__pmd_populate(pmd, __pa_symbol(kasan_zero_pte), PMD_TYPE_TABLE);
|
||
|
|
|
||
|
|
pte = pte_offset_kimg(pmd, addr);
|
||
|
|
do {
|
||
|
|
next = addr + PAGE_SIZE;
|
||
|
|
set_pte(pte, pfn_pte(sym_to_pfn(kasan_zero_page),
|
||
|
|
PAGE_KERNEL));
|
||
|
|
} while (pte++, addr = next, addr != end && pte_none(*pte));
|
||
|
|
}
|
||
|
|
|
||
|
|
static void __init kasan_early_pmd_populate(pud_t *pud,
|
||
|
|
unsigned long addr,
|
||
|
|
unsigned long end)
|
||
|
|
{
|
||
|
|
pmd_t *pmd;
|
||
|
|
unsigned long next;
|
||
|
|
|
||
|
|
if (pud_none(*pud))
|
||
|
|
__pud_populate(pud, __pa_symbol(kasan_zero_pmd), PMD_TYPE_TABLE);
|
||
|
|
|
||
|
|
pmd = pmd_offset_kimg(pud, addr);
|
||
|
|
do {
|
||
|
|
next = pmd_addr_end(addr, end);
|
||
|
|
kasan_early_pte_populate(pmd, addr, next);
|
||
|
|
} while (pmd++, addr = next, addr != end && pmd_none(*pmd));
|
||
|
|
}
|
||
|
|
|
||
|
|
static void __init kasan_early_pud_populate(pgd_t *pgd,
|
||
|
|
unsigned long addr,
|
||
|
|
unsigned long end)
|
||
|
|
{
|
||
|
|
pud_t *pud;
|
||
|
|
unsigned long next;
|
||
|
|
|
||
|
|
if (pgd_none(*pgd))
|
||
|
|
__pgd_populate(pgd, __pa_symbol(kasan_zero_pud), PUD_TYPE_TABLE);
|
||
|
|
|
||
|
|
pud = pud_offset_kimg(pgd, addr);
|
||
|
|
do {
|
||
|
|
next = pud_addr_end(addr, end);
|
||
|
|
kasan_early_pmd_populate(pud, addr, next);
|
||
|
|
} while (pud++, addr = next, addr != end && pud_none(*pud));
|
||
|
|
}
|
||
|
|
|
||
|
|
static void __init kasan_map_early_shadow(void)
|
||
|
|
{
|
||
|
|
unsigned long addr = KASAN_SHADOW_START;
|
||
|
|
unsigned long end = KASAN_SHADOW_END;
|
||
|
|
unsigned long next;
|
||
|
|
pgd_t *pgd;
|
||
|
|
|
||
|
|
pgd = pgd_offset_k(addr);
|
||
|
|
do {
|
||
|
|
next = pgd_addr_end(addr, end);
|
||
|
|
kasan_early_pud_populate(pgd, addr, next);
|
||
|
|
} while (pgd++, addr = next, addr != end);
|
||
|
|
}
|
||
|
|
|
||
|
|
asmlinkage void __init kasan_early_init(void)
|
||
|
|
{
|
||
|
|
BUILD_BUG_ON(KASAN_SHADOW_OFFSET != KASAN_SHADOW_END - (1UL << 61));
|
||
|
|
BUILD_BUG_ON(!IS_ALIGNED(KASAN_SHADOW_START, PGDIR_SIZE));
|
||
|
|
BUILD_BUG_ON(!IS_ALIGNED(KASAN_SHADOW_END, PGDIR_SIZE));
|
||
|
|
kasan_map_early_shadow();
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Copy the current shadow region into a new pgdir.
|
||
|
|
*/
|
||
|
|
void __init kasan_copy_shadow(pgd_t *pgdir)
|
||
|
|
{
|
||
|
|
pgd_t *pgd, *pgd_new, *pgd_end;
|
||
|
|
|
||
|
|
pgd = pgd_offset_k(KASAN_SHADOW_START);
|
||
|
|
pgd_end = pgd_offset_k(KASAN_SHADOW_END);
|
||
|
|
pgd_new = pgd_offset_raw(pgdir, KASAN_SHADOW_START);
|
||
|
|
do {
|
||
|
|
set_pgd(pgd_new, *pgd);
|
||
|
|
} while (pgd++, pgd_new++, pgd != pgd_end);
|
||
|
|
}
|
||
|
|
|
||
|
|
static void __init clear_pgds(unsigned long start,
|
||
|
|
unsigned long end)
|
||
|
|
{
|
||
|
|
/*
|
||
|
|
* Remove references to kasan page tables from
|
||
|
|
* swapper_pg_dir. pgd_clear() can't be used
|
||
|
|
* here because it's nop on 2,3-level pagetable setups
|
||
|
|
*/
|
||
|
|
for (; start < end; start += PGDIR_SIZE)
|
||
|
|
set_pgd(pgd_offset_k(start), __pgd(0));
|
||
|
|
}
|
||
|
|
|
||
|
|
void __init kasan_init(void)
|
||
|
|
{
|
||
|
|
u64 kimg_shadow_start, kimg_shadow_end;
|
||
|
|
u64 mod_shadow_start, mod_shadow_end;
|
||
|
|
struct memblock_region *reg;
|
||
|
|
int i;
|
||
|
|
|
||
|
|
kimg_shadow_start = (u64)kasan_mem_to_shadow(_text);
|
||
|
|
kimg_shadow_end = (u64)kasan_mem_to_shadow(_end);
|
||
|
|
|
||
|
|
mod_shadow_start = (u64)kasan_mem_to_shadow((void *)MODULES_VADDR);
|
||
|
|
mod_shadow_end = (u64)kasan_mem_to_shadow((void *)MODULES_END);
|
||
|
|
|
||
|
|
/*
|
||
|
|
* We are going to perform proper setup of shadow memory.
|
||
|
|
* At first we should unmap early shadow (clear_pgds() call bellow).
|
||
|
|
* However, instrumented code couldn't execute without shadow memory.
|
||
|
|
* tmp_pg_dir used to keep early shadow mapped until full shadow
|
||
|
|
* setup will be finished.
|
||
|
|
*/
|
||
|
|
memcpy(tmp_pg_dir, swapper_pg_dir, sizeof(tmp_pg_dir));
|
||
|
|
dsb(ishst);
|
||
|
|
cpu_replace_ttbr1(lm_alias(tmp_pg_dir));
|
||
|
|
|
||
|
|
clear_pgds(KASAN_SHADOW_START, KASAN_SHADOW_END);
|
||
|
|
|
||
|
|
vmemmap_populate(kimg_shadow_start, kimg_shadow_end,
|
||
|
|
pfn_to_nid(virt_to_pfn(lm_alias(_text))));
|
||
|
|
|
||
|
|
/*
|
||
|
|
* vmemmap_populate() has populated the shadow region that covers the
|
||
|
|
* kernel image with SWAPPER_BLOCK_SIZE mappings, so we have to round
|
||
|
|
* the start and end addresses to SWAPPER_BLOCK_SIZE as well, to prevent
|
||
|
|
* kasan_populate_zero_shadow() from replacing the page table entries
|
||
|
|
* (PMD or PTE) at the edges of the shadow region for the kernel
|
||
|
|
* image.
|
||
|
|
*/
|
||
|
|
kimg_shadow_start = round_down(kimg_shadow_start, SWAPPER_BLOCK_SIZE);
|
||
|
|
kimg_shadow_end = round_up(kimg_shadow_end, SWAPPER_BLOCK_SIZE);
|
||
|
|
|
||
|
|
kasan_populate_zero_shadow((void *)KASAN_SHADOW_START,
|
||
|
|
(void *)mod_shadow_start);
|
||
|
|
kasan_populate_zero_shadow((void *)kimg_shadow_end,
|
||
|
|
kasan_mem_to_shadow((void *)PAGE_OFFSET));
|
||
|
|
|
||
|
|
if (kimg_shadow_start > mod_shadow_end)
|
||
|
|
kasan_populate_zero_shadow((void *)mod_shadow_end,
|
||
|
|
(void *)kimg_shadow_start);
|
||
|
|
|
||
|
|
for_each_memblock(memory, reg) {
|
||
|
|
void *start = (void *)__phys_to_virt(reg->base);
|
||
|
|
void *end = (void *)__phys_to_virt(reg->base + reg->size);
|
||
|
|
|
||
|
|
if (start >= end)
|
||
|
|
break;
|
||
|
|
|
||
|
|
/*
|
||
|
|
* 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.
|
||
|
|
*/
|
||
|
|
vmemmap_populate((unsigned long)kasan_mem_to_shadow(start),
|
||
|
|
(unsigned long)kasan_mem_to_shadow(end) + 1,
|
||
|
|
pfn_to_nid(virt_to_pfn(start)));
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* KAsan may reuse the contents of kasan_zero_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_zero_pte[i],
|
||
|
|
pfn_pte(sym_to_pfn(kasan_zero_page), PAGE_KERNEL_RO));
|
||
|
|
|
||
|
|
memset(kasan_zero_page, 0, PAGE_SIZE);
|
||
|
|
cpu_replace_ttbr1(lm_alias(swapper_pg_dir));
|
||
|
|
|
||
|
|
/* At this point kasan is fully initialized. Enable error messages */
|
||
|
|
init_task.kasan_depth = 0;
|
||
|
|
pr_info("KernelAddressSanitizer initialized\n");
|
||
|
|
}
|