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/*
* Xtensa KASAN shadow map initialization
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 2017 Cadence Design Systems Inc.
*/
#include <linux/memblock.h>
#include <linux/init_task.h>
#include <linux/kasan.h>
#include <linux/kernel.h>
#include <asm/initialize_mmu.h>
#include <asm/tlbflush.h>
#include <asm/traps.h>
void __init kasan_early_init(void)
{
unsigned long vaddr = KASAN_SHADOW_START;
pgd_t *pgd = pgd_offset_k(vaddr);
p4d_t *p4d = p4d_offset(pgd, vaddr);
pud_t *pud = pud_offset(p4d, vaddr);
pmd_t *pmd = pmd_offset(pud, vaddr);
int i;
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 (vaddr = 0; vaddr < KASAN_SHADOW_SIZE; vaddr += PMD_SIZE, ++pmd) {
BUG_ON(!pmd_none(*pmd));
set_pmd(pmd, __pmd((unsigned long)kasan_early_shadow_pte));
}
early_trap_init();
}
static void __init populate(void *start, void *end)
{
unsigned long n_pages = (end - start) / PAGE_SIZE;
unsigned long n_pmds = n_pages / PTRS_PER_PTE;
unsigned long i, j;
unsigned long vaddr = (unsigned long)start;
pgd_t *pgd = pgd_offset_k(vaddr);
p4d_t *p4d = p4d_offset(pgd, vaddr);
pud_t *pud = pud_offset(p4d, vaddr);
pmd_t *pmd = pmd_offset(pud, vaddr);
pte_t *pte = memblock_alloc(n_pages * sizeof(pte_t), PAGE_SIZE);
if (!pte)
panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
__func__, n_pages * sizeof(pte_t), PAGE_SIZE);
pr_debug("%s: %p - %p\n", __func__, start, end);
for (i = j = 0; i < n_pmds; ++i) {
int k;
for (k = 0; k < PTRS_PER_PTE; ++k, ++j) {
phys_addr_t phys =
memblock_phys_alloc_range(PAGE_SIZE, PAGE_SIZE,
0,
MEMBLOCK_ALLOC_ANYWHERE);
if (!phys)
panic("Failed to allocate page table page\n");
set_pte(pte + j, pfn_pte(PHYS_PFN(phys), PAGE_KERNEL));
}
}
for (i = 0; i < n_pmds ; ++i, pte += PTRS_PER_PTE)
set_pmd(pmd + i, __pmd((unsigned long)pte));
local_flush_tlb_all();
memset(start, 0, end - start);
}
void __init kasan_init(void)
{
int i;
BUILD_BUG_ON(KASAN_SHADOW_OFFSET != KASAN_SHADOW_START -
(KASAN_START_VADDR >> KASAN_SHADOW_SCALE_SHIFT));
BUILD_BUG_ON(VMALLOC_START < KASAN_START_VADDR);
/*
* Replace shadow map pages that cover addresses from VMALLOC area
* start to the end of KSEG with clean writable pages.
*/
populate(kasan_mem_to_shadow((void *)VMALLOC_START),
kasan_mem_to_shadow((void *)XCHAL_KSEG_BYPASS_VADDR));
/*
* Write protect kasan_early_shadow_page and zero-initialize it again.
*/
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_RO));
local_flush_tlb_all();
memset(kasan_early_shadow_page, 0, PAGE_SIZE);
/* At this point kasan is fully initialized. Enable error messages. */
current->kasan_depth = 0;
pr_info("KernelAddressSanitizer initialized\n");
}
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