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// SPDX-License-Identifier: GPL-2.0
// Copyright (C) 2019 Andes Technology Corporation
#include <linux/pfn.h>
#include <linux/init_task.h>
#include <linux/kasan.h>
#include <linux/kernel.h>
#include <linux/memblock.h>
#include <linux/pgtable.h>
#include <asm/tlbflush.h>
#include <asm/fixmap.h>
#include <asm/pgalloc.h>
extern pgd_t early_pg_dir[PTRS_PER_PGD];
asmlinkage void __init kasan_early_init(void)
{
uintptr_t i;
pgd_t *pgd = early_pg_dir + pgd_index(KASAN_SHADOW_START);
for (i = 0; i < PTRS_PER_PTE; ++i)
set_pte(kasan_early_shadow_pte + i,
mk_pte(virt_to_page(kasan_early_shadow_page),
PAGE_KERNEL));
for (i = 0; i < PTRS_PER_PMD; ++i)
set_pmd(kasan_early_shadow_pmd + i,
pfn_pmd(PFN_DOWN
(__pa((uintptr_t) kasan_early_shadow_pte)),
__pgprot(_PAGE_TABLE)));
for (i = KASAN_SHADOW_START; i < KASAN_SHADOW_END;
i += PGDIR_SIZE, ++pgd)
set_pgd(pgd,
pfn_pgd(PFN_DOWN
(__pa(((uintptr_t) kasan_early_shadow_pmd))),
__pgprot(_PAGE_TABLE)));
/* init for swapper_pg_dir */
pgd = pgd_offset_k(KASAN_SHADOW_START);
for (i = KASAN_SHADOW_START; i < KASAN_SHADOW_END;
i += PGDIR_SIZE, ++pgd)
set_pgd(pgd,
pfn_pgd(PFN_DOWN
(__pa(((uintptr_t) kasan_early_shadow_pmd))),
__pgprot(_PAGE_TABLE)));
local_flush_tlb_all();
}
static void kasan_populate_pte(pmd_t *pmd, unsigned long vaddr, unsigned long end)
{
phys_addr_t phys_addr;
pte_t *ptep, *base_pte;
if (pmd_none(*pmd))
base_pte = memblock_alloc(PTRS_PER_PTE * sizeof(pte_t), PAGE_SIZE);
else
base_pte = (pte_t *)pmd_page_vaddr(*pmd);
ptep = base_pte + pte_index(vaddr);
do {
if (pte_none(*ptep)) {
phys_addr = memblock_phys_alloc(PAGE_SIZE, PAGE_SIZE);
set_pte(ptep, pfn_pte(PFN_DOWN(phys_addr), PAGE_KERNEL));
}
} while (ptep++, vaddr += PAGE_SIZE, vaddr != end);
set_pmd(pmd, pfn_pmd(PFN_DOWN(__pa(base_pte)), PAGE_TABLE));
}
static void kasan_populate_pmd(pgd_t *pgd, unsigned long vaddr, unsigned long end)
{
phys_addr_t phys_addr;
pmd_t *pmdp, *base_pmd;
unsigned long next;
base_pmd = (pmd_t *)pgd_page_vaddr(*pgd);
if (base_pmd == lm_alias(kasan_early_shadow_pmd))
base_pmd = memblock_alloc(PTRS_PER_PMD * sizeof(pmd_t), PAGE_SIZE);
pmdp = base_pmd + pmd_index(vaddr);
do {
next = pmd_addr_end(vaddr, end);
if (pmd_none(*pmdp) && IS_ALIGNED(vaddr, PMD_SIZE) && (next - vaddr) >= PMD_SIZE) {
phys_addr = memblock_phys_alloc(PMD_SIZE, PMD_SIZE);
if (phys_addr) {
set_pmd(pmdp, pfn_pmd(PFN_DOWN(phys_addr), PAGE_KERNEL));
continue;
}
}
kasan_populate_pte(pmdp, vaddr, next);
} while (pmdp++, vaddr = next, vaddr != end);
/*
* Wait for the whole PGD to be populated before setting the PGD in
* the page table, otherwise, if we did set the PGD before populating
* it entirely, memblock could allocate a page at a physical address
* where KASAN is not populated yet and then we'd get a page fault.
*/
set_pgd(pgd, pfn_pgd(PFN_DOWN(__pa(base_pmd)), PAGE_TABLE));
}
static void kasan_populate_pgd(unsigned long vaddr, unsigned long end)
{
phys_addr_t phys_addr;
pgd_t *pgdp = pgd_offset_k(vaddr);
unsigned long next;
do {
next = pgd_addr_end(vaddr, end);
/*
* pgdp can't be none since kasan_early_init initialized all KASAN
* shadow region with kasan_early_shadow_pmd: if this is stillthe case,
* that means we can try to allocate a hugepage as a replacement.
*/
if (pgd_page_vaddr(*pgdp) == (unsigned long)lm_alias(kasan_early_shadow_pmd) &&
IS_ALIGNED(vaddr, PGDIR_SIZE) && (next - vaddr) >= PGDIR_SIZE) {
phys_addr = memblock_phys_alloc(PGDIR_SIZE, PGDIR_SIZE);
if (phys_addr) {
set_pgd(pgdp, pfn_pgd(PFN_DOWN(phys_addr), PAGE_KERNEL));
continue;
}
}
kasan_populate_pmd(pgdp, vaddr, next);
} while (pgdp++, vaddr = next, vaddr != end);
}
static void __init kasan_populate(void *start, void *end)
{
unsigned long vaddr = (unsigned long)start & PAGE_MASK;
unsigned long vend = PAGE_ALIGN((unsigned long)end);
kasan_populate_pgd(vaddr, vend);
local_flush_tlb_all();
memset(start, KASAN_SHADOW_INIT, end - start);
}
static void __init kasan_shallow_populate_pgd(unsigned long vaddr, unsigned long end)
{
unsigned long next;
void *p;
pgd_t *pgd_k = pgd_offset_k(vaddr);
do {
next = pgd_addr_end(vaddr, end);
if (pgd_page_vaddr(*pgd_k) == (unsigned long)lm_alias(kasan_early_shadow_pmd)) {
p = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
set_pgd(pgd_k, pfn_pgd(PFN_DOWN(__pa(p)), PAGE_TABLE));
}
} while (pgd_k++, vaddr = next, vaddr != end);
}
static void __init kasan_shallow_populate(void *start, void *end)
{
unsigned long vaddr = (unsigned long)start & PAGE_MASK;
unsigned long vend = PAGE_ALIGN((unsigned long)end);
kasan_shallow_populate_pgd(vaddr, vend);
}
void __init kasan_init(void)
{
phys_addr_t _start, _end;
u64 i;
/*
* Populate all kernel virtual address space with kasan_early_shadow_page
* except for the linear mapping and the modules/kernel/BPF mapping.
*/
kasan_populate_early_shadow((void *)KASAN_SHADOW_START,
(void *)kasan_mem_to_shadow((void *)
VMEMMAP_END));
if (IS_ENABLED(CONFIG_KASAN_VMALLOC))
kasan_shallow_populate(
(void *)kasan_mem_to_shadow((void *)VMALLOC_START),
(void *)kasan_mem_to_shadow((void *)VMALLOC_END));
else
kasan_populate_early_shadow(
(void *)kasan_mem_to_shadow((void *)VMALLOC_START),
(void *)kasan_mem_to_shadow((void *)VMALLOC_END));
/* Populate the linear mapping */
for_each_mem_range(i, &_start, &_end) {
void *start = (void *)__va(_start);
void *end = (void *)__va(_end);
if (start >= end)
break;
kasan_populate(kasan_mem_to_shadow(start), kasan_mem_to_shadow(end));
};
/* Populate kernel, BPF, modules mapping */
kasan_populate(kasan_mem_to_shadow((const void *)MODULES_VADDR),
kasan_mem_to_shadow((const void *)BPF_JIT_REGION_END));
for (i = 0; i < PTRS_PER_PTE; i++)
set_pte(&kasan_early_shadow_pte[i],
mk_pte(virt_to_page(kasan_early_shadow_page),
__pgprot(_PAGE_PRESENT | _PAGE_READ |
_PAGE_ACCESSED)));
memset(kasan_early_shadow_page, KASAN_SHADOW_INIT, PAGE_SIZE);
init_task.kasan_depth = 0;
}
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