projects / linux-2.6-block.git / blame
| Commit | Line | Data |
|---|---|---|
| c633544a MF |
1 | /* |
| 2 | * Xtensa KASAN shadow map initialization | |
| 3 | * | |
| 4 | * This file is subject to the terms and conditions of the GNU General Public | |
| 5 | * License. See the file "COPYING" in the main directory of this archive | |
| 6 | * for more details. | |
| 7 | * | |
| 8 | * Copyright (C) 2017 Cadence Design Systems Inc. | |
| 9 | */ | |
| 10 | ||
| 11 | #include <linux/bootmem.h> | |
| 12 | #include <linux/init_task.h> | |
| 13 | #include <linux/kasan.h> | |
| 14 | #include <linux/kernel.h> | |
| 15 | #include <linux/memblock.h> | |
| 16 | #include <asm/initialize_mmu.h> | |
| 17 | #include <asm/tlbflush.h> | |
| 18 | #include <asm/traps.h> | |
| 19 | ||
| 20 | void __init kasan_early_init(void) | |
| 21 | { | |
| 22 | unsigned long vaddr = KASAN_SHADOW_START; | |
| 23 | pgd_t *pgd = pgd_offset_k(vaddr); | |
| 24 | pmd_t *pmd = pmd_offset(pgd, vaddr); | |
| 25 | int i; | |
| 26 | ||
| 27 | for (i = 0; i < PTRS_PER_PTE; ++i) | |
| 28 | set_pte(kasan_zero_pte + i, | |
| 29 | mk_pte(virt_to_page(kasan_zero_page), PAGE_KERNEL)); | |
| 30 | ||
| 31 | for (vaddr = 0; vaddr < KASAN_SHADOW_SIZE; vaddr += PMD_SIZE, ++pmd) { | |
| 32 | BUG_ON(!pmd_none(*pmd)); | |
| 33 | set_pmd(pmd, __pmd((unsigned long)kasan_zero_pte)); | |
| 34 | } | |
| 35 | early_trap_init(); | |
| 36 | } | |
| 37 | ||
| 38 | static void __init populate(void *start, void *end) | |
| 39 | { | |
| 40 | unsigned long n_pages = (end - start) / PAGE_SIZE; | |
| 41 | unsigned long n_pmds = n_pages / PTRS_PER_PTE; | |
| 42 | unsigned long i, j; | |
| 43 | unsigned long vaddr = (unsigned long)start; | |
| 44 | pgd_t *pgd = pgd_offset_k(vaddr); | |
| 45 | pmd_t *pmd = pmd_offset(pgd, vaddr); | |
| eb31d559 | 46 | pte_t *pte = memblock_alloc(n_pages * sizeof(pte_t), PAGE_SIZE); |
| c633544a MF |
47 | |
| 48 | pr_debug("%s: %p - %p\n", __func__, start, end); | |
| 49 | ||
| 50 | for (i = j = 0; i < n_pmds; ++i) { | |
| 51 | int k; | |
| 52 | ||
| 53 | for (k = 0; k < PTRS_PER_PTE; ++k, ++j) { | |
| 54 | phys_addr_t phys = | |
| 55 | memblock_alloc_base(PAGE_SIZE, PAGE_SIZE, | |
| 56 | MEMBLOCK_ALLOC_ANYWHERE); | |
| 57 | ||
| 58 | set_pte(pte + j, pfn_pte(PHYS_PFN(phys), PAGE_KERNEL)); | |
| 59 | } | |
| 60 | } | |
| 61 | ||
| 62 | for (i = 0; i < n_pmds ; ++i, pte += PTRS_PER_PTE) | |
| 63 | set_pmd(pmd + i, __pmd((unsigned long)pte)); | |
| 64 | ||
| 65 | local_flush_tlb_all(); | |
| 66 | memset(start, 0, end - start); | |
| 67 | } | |
| 68 | ||
| 69 | void __init kasan_init(void) | |
| 70 | { | |
| 71 | int i; | |
| 72 | ||
| 73 | BUILD_BUG_ON(KASAN_SHADOW_OFFSET != KASAN_SHADOW_START - | |
| 74 | (KASAN_START_VADDR >> KASAN_SHADOW_SCALE_SHIFT)); | |
| 75 | BUILD_BUG_ON(VMALLOC_START < KASAN_START_VADDR); | |
| 76 | ||
| 77 | /* | |
| 78 | * Replace shadow map pages that cover addresses from VMALLOC area | |
| 79 | * start to the end of KSEG with clean writable pages. | |
| 80 | */ | |
| 81 | populate(kasan_mem_to_shadow((void *)VMALLOC_START), | |
| 82 | kasan_mem_to_shadow((void *)XCHAL_KSEG_BYPASS_VADDR)); | |
| 83 | ||
| 84 | /* Write protect kasan_zero_page and zero-initialize it again. */ | |
| 85 | for (i = 0; i < PTRS_PER_PTE; ++i) | |
| 86 | set_pte(kasan_zero_pte + i, | |
| 87 | mk_pte(virt_to_page(kasan_zero_page), PAGE_KERNEL_RO)); | |
| 88 | ||
| 89 | local_flush_tlb_all(); | |
| 90 | memset(kasan_zero_page, 0, PAGE_SIZE); | |
| 91 | ||
| 92 | /* At this point kasan is fully initialized. Enable error messages. */ | |
| 93 | current->kasan_depth = 0; | |
| 94 | pr_info("KernelAddressSanitizer initialized\n"); | |
| 95 | } |