1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * KASAN for 64-bit Book3e powerpc 4 * 5 * Copyright 2022, Christophe Leroy, CS GROUP France 6 */ 7 8 #define DISABLE_BRANCH_PROFILING 9 10 #include <linux/kasan.h> 11 #include <linux/printk.h> 12 #include <linux/memblock.h> 13 #include <linux/set_memory.h> 14 15 #include <asm/pgalloc.h> 16 17 static inline bool kasan_pud_table(p4d_t p4d) 18 { 19 return p4d_page(p4d) == virt_to_page(lm_alias(kasan_early_shadow_pud)); 20 } 21 22 static inline bool kasan_pmd_table(pud_t pud) 23 { 24 return pud_page(pud) == virt_to_page(lm_alias(kasan_early_shadow_pmd)); 25 } 26 27 static inline bool kasan_pte_table(pmd_t pmd) 28 { 29 return pmd_page(pmd) == virt_to_page(lm_alias(kasan_early_shadow_pte)); 30 } 31 32 static int __init kasan_map_kernel_page(unsigned long ea, unsigned long pa, pgprot_t prot) 33 { 34 pgd_t *pgdp; 35 p4d_t *p4dp; 36 pud_t *pudp; 37 pmd_t *pmdp; 38 pte_t *ptep; 39 40 pgdp = pgd_offset_k(ea); 41 p4dp = p4d_offset(pgdp, ea); 42 if (kasan_pud_table(*p4dp)) { 43 pudp = memblock_alloc(PUD_TABLE_SIZE, PUD_TABLE_SIZE); 44 memcpy(pudp, kasan_early_shadow_pud, PUD_TABLE_SIZE); 45 p4d_populate(&init_mm, p4dp, pudp); 46 } 47 pudp = pud_offset(p4dp, ea); 48 if (kasan_pmd_table(*pudp)) { 49 pmdp = memblock_alloc(PMD_TABLE_SIZE, PMD_TABLE_SIZE); 50 memcpy(pmdp, kasan_early_shadow_pmd, PMD_TABLE_SIZE); 51 pud_populate(&init_mm, pudp, pmdp); 52 } 53 pmdp = pmd_offset(pudp, ea); 54 if (kasan_pte_table(*pmdp)) { 55 ptep = memblock_alloc(PTE_TABLE_SIZE, PTE_TABLE_SIZE); 56 memcpy(ptep, kasan_early_shadow_pte, PTE_TABLE_SIZE); 57 pmd_populate_kernel(&init_mm, pmdp, ptep); 58 } 59 ptep = pte_offset_kernel(pmdp, ea); 60 61 __set_pte_at(&init_mm, ea, ptep, pfn_pte(pa >> PAGE_SHIFT, prot), 0); 62 63 return 0; 64 } 65 66 static void __init kasan_init_phys_region(void *start, void *end) 67 { 68 unsigned long k_start, k_end, k_cur; 69 void *va; 70 71 if (start >= end) 72 return; 73 74 k_start = ALIGN_DOWN((unsigned long)kasan_mem_to_shadow(start), PAGE_SIZE); 75 k_end = ALIGN((unsigned long)kasan_mem_to_shadow(end), PAGE_SIZE); 76 77 va = memblock_alloc(k_end - k_start, PAGE_SIZE); 78 for (k_cur = k_start; k_cur < k_end; k_cur += PAGE_SIZE, va += PAGE_SIZE) 79 kasan_map_kernel_page(k_cur, __pa(va), PAGE_KERNEL); 80 } 81 82 void __init kasan_early_init(void) 83 { 84 int i; 85 unsigned long addr; 86 pgd_t *pgd = pgd_offset_k(KASAN_SHADOW_START); 87 pte_t zero_pte = pfn_pte(virt_to_pfn(kasan_early_shadow_page), PAGE_KERNEL); 88 89 BUILD_BUG_ON(!IS_ALIGNED(KASAN_SHADOW_START, PGDIR_SIZE)); 90 BUILD_BUG_ON(!IS_ALIGNED(KASAN_SHADOW_END, PGDIR_SIZE)); 91 92 for (i = 0; i < PTRS_PER_PTE; i++) 93 __set_pte_at(&init_mm, (unsigned long)kasan_early_shadow_page, 94 &kasan_early_shadow_pte[i], zero_pte, 0); 95 96 for (i = 0; i < PTRS_PER_PMD; i++) 97 pmd_populate_kernel(&init_mm, &kasan_early_shadow_pmd[i], 98 kasan_early_shadow_pte); 99 100 for (i = 0; i < PTRS_PER_PUD; i++) 101 pud_populate(&init_mm, &kasan_early_shadow_pud[i], 102 kasan_early_shadow_pmd); 103 104 for (addr = KASAN_SHADOW_START; addr != KASAN_SHADOW_END; addr += PGDIR_SIZE) 105 p4d_populate(&init_mm, p4d_offset(pgd++, addr), kasan_early_shadow_pud); 106 } 107 108 void __init kasan_init(void) 109 { 110 phys_addr_t start, end; 111 u64 i; 112 pte_t zero_pte = pfn_pte(virt_to_pfn(kasan_early_shadow_page), PAGE_KERNEL_RO); 113 114 for_each_mem_range(i, &start, &end) 115 kasan_init_phys_region((void *)start, (void *)end); 116 117 if (IS_ENABLED(CONFIG_KASAN_VMALLOC)) 118 kasan_remove_zero_shadow((void *)VMALLOC_START, VMALLOC_SIZE); 119 120 for (i = 0; i < PTRS_PER_PTE; i++) 121 __set_pte_at(&init_mm, (unsigned long)kasan_early_shadow_page, 122 &kasan_early_shadow_pte[i], zero_pte, 0); 123 124 flush_tlb_kernel_range(KASAN_SHADOW_START, KASAN_SHADOW_END); 125 126 memset(kasan_early_shadow_page, 0, PAGE_SIZE); 127 128 /* Enable error messages */ 129 init_task.kasan_depth = 0; 130 pr_info("KASAN init done\n"); 131 } 132 133 void __init kasan_late_init(void) { } 134