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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];
static void __init 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 __init 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 __init kasan_populate_pgd(pgd_t *pgdp,
unsigned long vaddr, unsigned long end,
bool early)
{
phys_addr_t phys_addr;
unsigned long next;
do {
next = pgd_addr_end(vaddr, end);
if (IS_ALIGNED(vaddr, PGDIR_SIZE) && (next - vaddr) >= PGDIR_SIZE) {
if (early) {
phys_addr = __pa((uintptr_t)kasan_early_shadow_pgd_next);
set_pgd(pgdp, pfn_pgd(PFN_DOWN(phys_addr), PAGE_TABLE));
continue;
} else if (pgd_page_vaddr(*pgdp) ==
(unsigned long)lm_alias(kasan_early_shadow_pgd_next)) {
/*
* pgdp can't be none since kasan_early_init
* initialized all KASAN shadow region with
* kasan_early_shadow_pud: if this is still the
* case, that means we can try to allocate a
* hugepage as a replacement.
*/
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);
}
asmlinkage void __init kasan_early_init(void)
{
uintptr_t i;
BUILD_BUG_ON(KASAN_SHADOW_OFFSET !=
KASAN_SHADOW_END - (1UL << (64 - KASAN_SHADOW_SCALE_SHIFT)));
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)),
PAGE_TABLE));
if (pgtable_l4_enabled) {
for (i = 0; i < PTRS_PER_PUD; ++i)
set_pud(kasan_early_shadow_pud + i,
pfn_pud(PFN_DOWN
(__pa(((uintptr_t)kasan_early_shadow_pmd))),
PAGE_TABLE));
}
kasan_populate_pgd(early_pg_dir + pgd_index(KASAN_SHADOW_START),
KASAN_SHADOW_START, KASAN_SHADOW_END, true);
local_flush_tlb_all();
}
void __init kasan_swapper_init(void)
{
kasan_populate_pgd(pgd_offset_k(KASAN_SHADOW_START),
KASAN_SHADOW_START, KASAN_SHADOW_END, true);
local_flush_tlb_all();
}
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(pgd_offset_k(vaddr), vaddr, vend, false);
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);
local_flush_tlb_all();
}
void __init kasan_init(void)
{
phys_addr_t p_start, p_end;
u64 i;
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));
/* Populate the linear mapping */
for_each_mem_range(i, &p_start, &p_end) {
void *start = (void *)__va(p_start);
void *end = (void *)__va(p_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 *)MODULES_VADDR + SZ_2G));
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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