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;
38 void *kasan_mem_to_shadow(const void *addr)
40 if (!kasan_arch_is_ready()) {
41 return (void *)(kasan_early_shadow_page);
43 unsigned long maddr = (unsigned long)addr;
44 unsigned long xrange = (maddr >> XRANGE_SHIFT) & 0xffff;
45 unsigned long offset = 0;
47 maddr &= XRANGE_SHADOW_MASK;
50 offset = XKPRANGE_CC_SHADOW_OFFSET;
53 offset = XKPRANGE_UC_SHADOW_OFFSET;
56 offset = XKVRANGE_VC_SHADOW_OFFSET;
63 return (void *)((maddr >> KASAN_SHADOW_SCALE_SHIFT) + offset);
67 const void *kasan_shadow_to_mem(const void *shadow_addr)
69 unsigned long addr = (unsigned long)shadow_addr;
71 if (unlikely(addr > KASAN_SHADOW_END) ||
72 unlikely(addr < KASAN_SHADOW_START)) {
77 if (addr >= XKVRANGE_VC_SHADOW_OFFSET)
78 return (void *)(((addr - XKVRANGE_VC_SHADOW_OFFSET) << KASAN_SHADOW_SCALE_SHIFT) + XKVRANGE_VC_START);
79 else if (addr >= XKPRANGE_UC_SHADOW_OFFSET)
80 return (void *)(((addr - XKPRANGE_UC_SHADOW_OFFSET) << KASAN_SHADOW_SCALE_SHIFT) + XKPRANGE_UC_START);
81 else if (addr >= XKPRANGE_CC_SHADOW_OFFSET)
82 return (void *)(((addr - XKPRANGE_CC_SHADOW_OFFSET) << KASAN_SHADOW_SCALE_SHIFT) + XKPRANGE_CC_START);
90 * Alloc memory for shadow memory page table.
92 static phys_addr_t __init kasan_alloc_zeroed_page(int node)
94 void *p = memblock_alloc_try_nid(PAGE_SIZE, PAGE_SIZE,
95 __pa(MAX_DMA_ADDRESS), MEMBLOCK_ALLOC_ACCESSIBLE, node);
97 panic("%s: Failed to allocate %lu bytes align=0x%lx nid=%d from=%llx\n",
98 __func__, PAGE_SIZE, PAGE_SIZE, node, __pa(MAX_DMA_ADDRESS));
103 static pte_t *__init kasan_pte_offset(pmd_t *pmdp, unsigned long addr, int node, bool early)
105 if (__pmd_none(early, READ_ONCE(*pmdp))) {
106 phys_addr_t pte_phys = early ?
107 __pa_symbol(kasan_early_shadow_pte) : kasan_alloc_zeroed_page(node);
109 memcpy(__va(pte_phys), kasan_early_shadow_pte, sizeof(kasan_early_shadow_pte));
110 pmd_populate_kernel(NULL, pmdp, (pte_t *)__va(pte_phys));
113 return pte_offset_kernel(pmdp, addr);
116 static pmd_t *__init kasan_pmd_offset(pud_t *pudp, unsigned long addr, int node, bool early)
118 if (__pud_none(early, READ_ONCE(*pudp))) {
119 phys_addr_t pmd_phys = early ?
120 __pa_symbol(kasan_early_shadow_pmd) : kasan_alloc_zeroed_page(node);
122 memcpy(__va(pmd_phys), kasan_early_shadow_pmd, sizeof(kasan_early_shadow_pmd));
123 pud_populate(&init_mm, pudp, (pmd_t *)__va(pmd_phys));
126 return pmd_offset(pudp, addr);
129 static pud_t *__init kasan_pud_offset(p4d_t *p4dp, unsigned long addr, int node, bool early)
131 if (__p4d_none(early, READ_ONCE(*p4dp))) {
132 phys_addr_t pud_phys = early ?
133 __pa_symbol(kasan_early_shadow_pud) : kasan_alloc_zeroed_page(node);
135 memcpy(__va(pud_phys), kasan_early_shadow_pud, sizeof(kasan_early_shadow_pud));
136 p4d_populate(&init_mm, p4dp, (pud_t *)__va(pud_phys));
139 return pud_offset(p4dp, addr);
142 static void __init kasan_pte_populate(pmd_t *pmdp, unsigned long addr,
143 unsigned long end, int node, bool early)
146 pte_t *ptep = kasan_pte_offset(pmdp, addr, node, early);
149 phys_addr_t page_phys = early ?
150 __pa_symbol(kasan_early_shadow_page)
151 : kasan_alloc_zeroed_page(node);
152 next = addr + PAGE_SIZE;
153 set_pte(ptep, pfn_pte(__phys_to_pfn(page_phys), PAGE_KERNEL));
154 } while (ptep++, addr = next, addr != end && __pte_none(early, READ_ONCE(*ptep)));
157 static void __init kasan_pmd_populate(pud_t *pudp, unsigned long addr,
158 unsigned long end, int node, bool early)
161 pmd_t *pmdp = kasan_pmd_offset(pudp, addr, node, early);
164 next = pmd_addr_end(addr, end);
165 kasan_pte_populate(pmdp, addr, next, node, early);
166 } while (pmdp++, addr = next, addr != end && __pmd_none(early, READ_ONCE(*pmdp)));
169 static void __init kasan_pud_populate(p4d_t *p4dp, unsigned long addr,
170 unsigned long end, int node, bool early)
173 pud_t *pudp = kasan_pud_offset(p4dp, addr, node, early);
176 next = pud_addr_end(addr, end);
177 kasan_pmd_populate(pudp, addr, next, node, early);
178 } while (pudp++, addr = next, addr != end);
181 static void __init kasan_p4d_populate(pgd_t *pgdp, unsigned long addr,
182 unsigned long end, int node, bool early)
185 p4d_t *p4dp = p4d_offset(pgdp, addr);
188 next = p4d_addr_end(addr, end);
189 kasan_pud_populate(p4dp, addr, next, node, early);
190 } while (p4dp++, addr = next, addr != end);
193 static void __init kasan_pgd_populate(unsigned long addr, unsigned long end,
194 int node, bool early)
199 pgdp = pgd_offset_k(addr);
202 next = pgd_addr_end(addr, end);
203 kasan_p4d_populate(pgdp, addr, next, node, early);
204 } while (pgdp++, addr = next, addr != end);
208 /* Set up full kasan mappings, ensuring that the mapped pages are zeroed */
209 static void __init kasan_map_populate(unsigned long start, unsigned long end,
212 kasan_pgd_populate(start & PAGE_MASK, PAGE_ALIGN(end), node, false);
215 asmlinkage void __init kasan_early_init(void)
217 BUILD_BUG_ON(!IS_ALIGNED(KASAN_SHADOW_START, PGDIR_SIZE));
218 BUILD_BUG_ON(!IS_ALIGNED(KASAN_SHADOW_END, PGDIR_SIZE));
221 static inline void kasan_set_pgd(pgd_t *pgdp, pgd_t pgdval)
223 WRITE_ONCE(*pgdp, pgdval);
226 static void __init clear_pgds(unsigned long start, unsigned long end)
229 * Remove references to kasan page tables from
230 * swapper_pg_dir. pgd_clear() can't be used
231 * here because it's nop on 2,3-level pagetable setups
233 for (; start < end; start += PGDIR_SIZE)
234 kasan_set_pgd((pgd_t *)pgd_offset_k(start), __pgd(0));
237 void __init kasan_init(void)
240 phys_addr_t pa_start, pa_end;
243 * PGD was populated as invalid_pmd_table or invalid_pud_table
244 * in pagetable_init() which depends on how many levels of page
245 * table you are using, but we had to clean the gpd of kasan
246 * shadow memory, as the pgd value is none-zero.
247 * The assertion pgd_none is going to be false and the formal populate
248 * afterwards is not going to create any new pgd at all.
250 memcpy(kasan_pg_dir, swapper_pg_dir, sizeof(kasan_pg_dir));
251 csr_write64(__pa_symbol(kasan_pg_dir), LOONGARCH_CSR_PGDH);
252 local_flush_tlb_all();
254 clear_pgds(KASAN_SHADOW_START, KASAN_SHADOW_END);
256 /* Maps everything to a single page of zeroes */
257 kasan_pgd_populate(KASAN_SHADOW_START, KASAN_SHADOW_END, NUMA_NO_NODE, true);
259 kasan_populate_early_shadow(kasan_mem_to_shadow((void *)VMALLOC_START),
260 kasan_mem_to_shadow((void *)KFENCE_AREA_END));
262 kasan_early_stage = false;
264 /* Populate the linear mapping */
265 for_each_mem_range(i, &pa_start, &pa_end) {
266 void *start = (void *)phys_to_virt(pa_start);
267 void *end = (void *)phys_to_virt(pa_end);
272 kasan_map_populate((unsigned long)kasan_mem_to_shadow(start),
273 (unsigned long)kasan_mem_to_shadow(end), NUMA_NO_NODE);
276 /* Populate modules mapping */
277 kasan_map_populate((unsigned long)kasan_mem_to_shadow((void *)MODULES_VADDR),
278 (unsigned long)kasan_mem_to_shadow((void *)MODULES_END), NUMA_NO_NODE);
280 * KAsan may reuse the contents of kasan_early_shadow_pte directly, so we
281 * should make sure that it maps the zero page read-only.
283 for (i = 0; i < PTRS_PER_PTE; i++)
284 set_pte(&kasan_early_shadow_pte[i],
285 pfn_pte(__phys_to_pfn(__pa_symbol(kasan_early_shadow_page)), PAGE_KERNEL_RO));
287 memset(kasan_early_shadow_page, 0, PAGE_SIZE);
288 csr_write64(__pa_symbol(swapper_pg_dir), LOONGARCH_CSR_PGDH);
289 local_flush_tlb_all();
291 /* At this point kasan is fully initialized. Enable error messages */
292 init_task.kasan_depth = 0;
293 pr_info("KernelAddressSanitizer initialized.\n");