1 // SPDX-License-Identifier: GPL-2.0-only
3 * Copyright (C) 2023 Loongson Technology Corporation Limited
5 #define pr_fmt(fmt) "kasan: " fmt
6 #include <linux/kasan.h>
7 #include <linux/memblock.h>
8 #include <linux/sched/task.h>
10 #include <asm/tlbflush.h>
11 #include <asm/pgalloc.h>
12 #include <asm-generic/sections.h>
14 static pgd_t kasan_pg_dir[PTRS_PER_PGD] __initdata __aligned(PAGE_SIZE);
16 #ifdef __PAGETABLE_PUD_FOLDED
17 #define __p4d_none(early, p4d) (0)
19 #define __p4d_none(early, p4d) (early ? (p4d_val(p4d) == 0) : \
20 (__pa(p4d_val(p4d)) == (unsigned long)__pa(kasan_early_shadow_pud)))
23 #ifdef __PAGETABLE_PMD_FOLDED
24 #define __pud_none(early, pud) (0)
26 #define __pud_none(early, pud) (early ? (pud_val(pud) == 0) : \
27 (__pa(pud_val(pud)) == (unsigned long)__pa(kasan_early_shadow_pmd)))
30 #define __pmd_none(early, pmd) (early ? (pmd_val(pmd) == 0) : \
31 (__pa(pmd_val(pmd)) == (unsigned long)__pa(kasan_early_shadow_pte)))
33 #define __pte_none(early, pte) (early ? pte_none(pte) : \
34 ((pte_val(pte) & _PFN_MASK) == (unsigned long)__pa(kasan_early_shadow_page)))
36 bool kasan_early_stage = true;
39 * Alloc memory for shadow memory page table.
41 static phys_addr_t __init kasan_alloc_zeroed_page(int node)
43 void *p = memblock_alloc_try_nid(PAGE_SIZE, PAGE_SIZE,
44 __pa(MAX_DMA_ADDRESS), MEMBLOCK_ALLOC_ACCESSIBLE, node);
46 panic("%s: Failed to allocate %lu bytes align=0x%lx nid=%d from=%llx\n",
47 __func__, PAGE_SIZE, PAGE_SIZE, node, __pa(MAX_DMA_ADDRESS));
52 static pte_t *__init kasan_pte_offset(pmd_t *pmdp, unsigned long addr, int node, bool early)
54 if (__pmd_none(early, READ_ONCE(*pmdp))) {
55 phys_addr_t pte_phys = early ?
56 __pa_symbol(kasan_early_shadow_pte) : kasan_alloc_zeroed_page(node);
58 memcpy(__va(pte_phys), kasan_early_shadow_pte, sizeof(kasan_early_shadow_pte));
59 pmd_populate_kernel(NULL, pmdp, (pte_t *)__va(pte_phys));
62 return pte_offset_kernel(pmdp, addr);
65 static pmd_t *__init kasan_pmd_offset(pud_t *pudp, unsigned long addr, int node, bool early)
67 if (__pud_none(early, READ_ONCE(*pudp))) {
68 phys_addr_t pmd_phys = early ?
69 __pa_symbol(kasan_early_shadow_pmd) : kasan_alloc_zeroed_page(node);
71 memcpy(__va(pmd_phys), kasan_early_shadow_pmd, sizeof(kasan_early_shadow_pmd));
72 pud_populate(&init_mm, pudp, (pmd_t *)__va(pmd_phys));
75 return pmd_offset(pudp, addr);
78 static pud_t *__init kasan_pud_offset(p4d_t *p4dp, unsigned long addr, int node, bool early)
80 if (__p4d_none(early, READ_ONCE(*p4dp))) {
81 phys_addr_t pud_phys = early ?
82 __pa_symbol(kasan_early_shadow_pud) : kasan_alloc_zeroed_page(node);
84 memcpy(__va(pud_phys), kasan_early_shadow_pud, sizeof(kasan_early_shadow_pud));
85 p4d_populate(&init_mm, p4dp, (pud_t *)__va(pud_phys));
88 return pud_offset(p4dp, addr);
91 static void __init kasan_pte_populate(pmd_t *pmdp, unsigned long addr,
92 unsigned long end, int node, bool early)
95 pte_t *ptep = kasan_pte_offset(pmdp, addr, node, early);
98 phys_addr_t page_phys = early ?
99 __pa_symbol(kasan_early_shadow_page)
100 : kasan_alloc_zeroed_page(node);
101 next = addr + PAGE_SIZE;
102 set_pte(ptep, pfn_pte(__phys_to_pfn(page_phys), PAGE_KERNEL));
103 } while (ptep++, addr = next, addr != end && __pte_none(early, READ_ONCE(*ptep)));
106 static void __init kasan_pmd_populate(pud_t *pudp, unsigned long addr,
107 unsigned long end, int node, bool early)
110 pmd_t *pmdp = kasan_pmd_offset(pudp, addr, node, early);
113 next = pmd_addr_end(addr, end);
114 kasan_pte_populate(pmdp, addr, next, node, early);
115 } while (pmdp++, addr = next, addr != end && __pmd_none(early, READ_ONCE(*pmdp)));
118 static void __init kasan_pud_populate(p4d_t *p4dp, unsigned long addr,
119 unsigned long end, int node, bool early)
122 pud_t *pudp = kasan_pud_offset(p4dp, addr, node, early);
125 next = pud_addr_end(addr, end);
126 kasan_pmd_populate(pudp, addr, next, node, early);
127 } while (pudp++, addr = next, addr != end);
130 static void __init kasan_p4d_populate(pgd_t *pgdp, unsigned long addr,
131 unsigned long end, int node, bool early)
134 p4d_t *p4dp = p4d_offset(pgdp, addr);
137 next = p4d_addr_end(addr, end);
138 kasan_pud_populate(p4dp, addr, next, node, early);
139 } while (p4dp++, addr = next, addr != end);
142 static void __init kasan_pgd_populate(unsigned long addr, unsigned long end,
143 int node, bool early)
148 pgdp = pgd_offset_k(addr);
151 next = pgd_addr_end(addr, end);
152 kasan_p4d_populate(pgdp, addr, next, node, early);
153 } while (pgdp++, addr = next, addr != end);
157 /* Set up full kasan mappings, ensuring that the mapped pages are zeroed */
158 static void __init kasan_map_populate(unsigned long start, unsigned long end,
161 kasan_pgd_populate(start & PAGE_MASK, PAGE_ALIGN(end), node, false);
164 asmlinkage void __init kasan_early_init(void)
166 BUILD_BUG_ON(!IS_ALIGNED(KASAN_SHADOW_START, PGDIR_SIZE));
167 BUILD_BUG_ON(!IS_ALIGNED(KASAN_SHADOW_END, PGDIR_SIZE));
170 static inline void kasan_set_pgd(pgd_t *pgdp, pgd_t pgdval)
172 WRITE_ONCE(*pgdp, pgdval);
175 static void __init clear_pgds(unsigned long start, unsigned long end)
178 * Remove references to kasan page tables from
179 * swapper_pg_dir. pgd_clear() can't be used
180 * here because it's nop on 2,3-level pagetable setups
182 for (; start < end; start += PGDIR_SIZE)
183 kasan_set_pgd((pgd_t *)pgd_offset_k(start), __pgd(0));
186 void __init kasan_init(void)
189 phys_addr_t pa_start, pa_end;
192 * PGD was populated as invalid_pmd_table or invalid_pud_table
193 * in pagetable_init() which depends on how many levels of page
194 * table you are using, but we had to clean the gpd of kasan
195 * shadow memory, as the pgd value is none-zero.
196 * The assertion pgd_none is going to be false and the formal populate
197 * afterwards is not going to create any new pgd at all.
199 memcpy(kasan_pg_dir, swapper_pg_dir, sizeof(kasan_pg_dir));
200 csr_write64(__pa_symbol(kasan_pg_dir), LOONGARCH_CSR_PGDH);
201 local_flush_tlb_all();
203 clear_pgds(KASAN_SHADOW_START, KASAN_SHADOW_END);
205 /* Maps everything to a single page of zeroes */
206 kasan_pgd_populate(KASAN_SHADOW_START, KASAN_SHADOW_END, NUMA_NO_NODE, true);
208 kasan_populate_early_shadow(kasan_mem_to_shadow((void *)VMALLOC_START),
209 kasan_mem_to_shadow((void *)KFENCE_AREA_END));
211 kasan_early_stage = false;
213 /* Populate the linear mapping */
214 for_each_mem_range(i, &pa_start, &pa_end) {
215 void *start = (void *)phys_to_virt(pa_start);
216 void *end = (void *)phys_to_virt(pa_end);
221 kasan_map_populate((unsigned long)kasan_mem_to_shadow(start),
222 (unsigned long)kasan_mem_to_shadow(end), NUMA_NO_NODE);
225 /* Populate modules mapping */
226 kasan_map_populate((unsigned long)kasan_mem_to_shadow((void *)MODULES_VADDR),
227 (unsigned long)kasan_mem_to_shadow((void *)MODULES_END), NUMA_NO_NODE);
229 * KAsan may reuse the contents of kasan_early_shadow_pte directly, so we
230 * should make sure that it maps the zero page read-only.
232 for (i = 0; i < PTRS_PER_PTE; i++)
233 set_pte(&kasan_early_shadow_pte[i],
234 pfn_pte(__phys_to_pfn(__pa_symbol(kasan_early_shadow_page)), PAGE_KERNEL_RO));
236 memset(kasan_early_shadow_page, 0, PAGE_SIZE);
237 csr_write64(__pa_symbol(swapper_pg_dir), LOONGARCH_CSR_PGDH);
238 local_flush_tlb_all();
240 /* At this point kasan is fully initialized. Enable error messages */
241 init_task.kasan_depth = 0;
242 pr_info("KernelAddressSanitizer initialized.\n");