| /* |
| * 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/bootmem.h> |
| #include <linux/init_task.h> |
| #include <linux/kasan.h> |
| #include <linux/kernel.h> |
| #include <linux/memblock.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); |
| pmd_t *pmd = pmd_offset(pgd, 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); |
| pmd_t *pmd = pmd_offset(pgd, vaddr); |
| pte_t *pte = memblock_virt_alloc(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_alloc_base(PAGE_SIZE, PAGE_SIZE, |
| MEMBLOCK_ALLOC_ANYWHERE); |
| |
| 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"); |
| } |