1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * KASAN for 64-bit Book3S powerpc 4 * 5 * Copyright 2019-2022, Daniel Axtens, IBM Corporation. 6 */ 7 8 /* 9 * ppc64 turns on virtual memory late in boot, after calling into generic code 10 * like the device-tree parser, so it uses this in conjunction with a hook in 11 * outline mode to avoid invalid access early in boot. 12 */ 13 14 #define DISABLE_BRANCH_PROFILING 15 16 #include <linux/kasan.h> 17 #include <linux/printk.h> 18 #include <linux/sched/task.h> 19 #include <linux/memblock.h> 20 #include <asm/pgalloc.h> 21 22 static void __init kasan_init_phys_region(void *start, void *end) 23 { 24 unsigned long k_start, k_end, k_cur; 25 void *va; 26 27 if (start >= end) 28 return; 29 30 k_start = ALIGN_DOWN((unsigned long)kasan_mem_to_shadow(start), PAGE_SIZE); 31 k_end = ALIGN((unsigned long)kasan_mem_to_shadow(end), PAGE_SIZE); 32 33 va = memblock_alloc_or_panic(k_end - k_start, PAGE_SIZE); 34 for (k_cur = k_start; k_cur < k_end; k_cur += PAGE_SIZE, va += PAGE_SIZE) 35 map_kernel_page(k_cur, __pa(va), PAGE_KERNEL); 36 } 37 38 void __init kasan_init(void) 39 { 40 /* 41 * We want to do the following things: 42 * 1) Map real memory into the shadow for all physical memblocks 43 * This takes us from c000... to c008... 44 * 2) Leave a hole over the shadow of vmalloc space. KASAN_VMALLOC 45 * will manage this for us. 46 * This takes us from c008... to c00a... 47 * 3) Map the 'early shadow'/zero page over iomap and vmemmap space. 48 * This takes us up to where we start at c00e... 49 */ 50 51 void *k_start = kasan_mem_to_shadow((void *)RADIX_VMALLOC_END); 52 void *k_end = kasan_mem_to_shadow((void *)RADIX_VMEMMAP_END); 53 phys_addr_t start, end; 54 u64 i; 55 pte_t zero_pte = pfn_pte(virt_to_pfn(kasan_early_shadow_page), PAGE_KERNEL); 56 57 if (!early_radix_enabled()) { 58 pr_warn("KASAN not enabled as it requires radix!"); 59 return; 60 } 61 62 for_each_mem_range(i, &start, &end) 63 kasan_init_phys_region(phys_to_virt(start), phys_to_virt(end)); 64 65 for (i = 0; i < PTRS_PER_PTE; i++) 66 __set_pte_at(&init_mm, (unsigned long)kasan_early_shadow_page, 67 &kasan_early_shadow_pte[i], zero_pte, 0); 68 69 for (i = 0; i < PTRS_PER_PMD; i++) 70 pmd_populate_kernel(&init_mm, &kasan_early_shadow_pmd[i], 71 kasan_early_shadow_pte); 72 73 for (i = 0; i < PTRS_PER_PUD; i++) 74 pud_populate(&init_mm, &kasan_early_shadow_pud[i], 75 kasan_early_shadow_pmd); 76 77 /* map the early shadow over the iomap and vmemmap space */ 78 kasan_populate_early_shadow(k_start, k_end); 79 80 /* mark early shadow region as RO and wipe it */ 81 zero_pte = pfn_pte(virt_to_pfn(kasan_early_shadow_page), PAGE_KERNEL_RO); 82 for (i = 0; i < PTRS_PER_PTE; i++) 83 __set_pte_at(&init_mm, (unsigned long)kasan_early_shadow_page, 84 &kasan_early_shadow_pte[i], zero_pte, 0); 85 86 /* 87 * clear_page relies on some cache info that hasn't been set up yet. 88 * It ends up looping ~forever and blows up other data. 89 * Use memset instead. 90 */ 91 memset(kasan_early_shadow_page, 0, PAGE_SIZE); 92 93 /* Enable error messages */ 94 init_task.kasan_depth = 0; 95 kasan_init_generic(); 96 } 97 98 void __init kasan_early_init(void) { } 99 100 void __init kasan_late_init(void) { } 101