arch/loongarch/mm/kasan_init.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2023 Loongson Technology Corporation Limited
   4  */
   5 #define pr_fmt(fmt) "kasan: " fmt
   6 #include <linux/kasan.h>
   7 #include <linux/memblock.h>
   8 #include <linux/sched/task.h>
   9
  10 #include <asm/tlbflush.h>
  11 #include <asm/pgalloc.h>
  12 #include <asm-generic/sections.h>
  13
  14 static pgd_t kasan_pg_dir[PTRS_PER_PGD] __initdata __aligned(PAGE_SIZE);
  15
  16 #ifdef __PAGETABLE_P4D_FOLDED
  17 #define __pgd_none(early, pgd) (0)
  18 #else
  19 #define __pgd_none(early, pgd) (early ? (pgd_val(pgd) == 0) : \
  20 (__pa(pgd_val(pgd)) == (unsigned long)__pa(kasan_early_shadow_p4d)))
  21 #endif
  22
  23 #ifdef __PAGETABLE_PUD_FOLDED
  24 #define __p4d_none(early, p4d) (0)
  25 #else
  26 #define __p4d_none(early, p4d) (early ? (p4d_val(p4d) == 0) : \
  27 (__pa(p4d_val(p4d)) == (unsigned long)__pa(kasan_early_shadow_pud)))
  28 #endif
  29
  30 #ifdef __PAGETABLE_PMD_FOLDED
  31 #define __pud_none(early, pud) (0)
  32 #else
  33 #define __pud_none(early, pud) (early ? (pud_val(pud) == 0) : \
  34 (__pa(pud_val(pud)) == (unsigned long)__pa(kasan_early_shadow_pmd)))
  35 #endif
  36
  37 #define __pmd_none(early, pmd) (early ? (pmd_val(pmd) == 0) : \
  38 (__pa(pmd_val(pmd)) == (unsigned long)__pa(kasan_early_shadow_pte)))
  39
  40 #define __pte_none(early, pte) (early ? pte_none(pte) : \
  41 ((pte_val(pte) & _PFN_MASK) == (unsigned long)__pa(kasan_early_shadow_page)))
  42
  43 bool kasan_early_stage = true;
  44
  45 void *kasan_mem_to_shadow(const void *addr)
  46 {
  47         if (!kasan_arch_is_ready()) {
  48                 return (void *)(kasan_early_shadow_page);
  49         } else {
  50                 unsigned long maddr = (unsigned long)addr;
  51                 unsigned long xrange = (maddr >> XRANGE_SHIFT) & 0xffff;
  52                 unsigned long offset = 0;
  53
  54                 if (maddr >= FIXADDR_START)
  55                         return (void *)(kasan_early_shadow_page);
  56
  57                 maddr &= XRANGE_SHADOW_MASK;
  58                 switch (xrange) {
  59                 case XKPRANGE_CC_SEG:
  60                         offset = XKPRANGE_CC_SHADOW_OFFSET;
  61                         break;
  62                 case XKPRANGE_UC_SEG:
  63                         offset = XKPRANGE_UC_SHADOW_OFFSET;
  64                         break;
  65                 case XKPRANGE_WC_SEG:
  66                         offset = XKPRANGE_WC_SHADOW_OFFSET;
  67                         break;
  68                 case XKVRANGE_VC_SEG:
  69                         offset = XKVRANGE_VC_SHADOW_OFFSET;
  70                         break;
  71                 default:
  72                         WARN_ON(1);
  73                         return NULL;
  74                 }
  75
  76                 return (void *)((maddr >> KASAN_SHADOW_SCALE_SHIFT) + offset);
  77         }
  78 }
  79
  80 const void *kasan_shadow_to_mem(const void *shadow_addr)
  81 {
  82         unsigned long addr = (unsigned long)shadow_addr;
  83
  84         if (unlikely(addr > KASAN_SHADOW_END) ||
  85                 unlikely(addr < KASAN_SHADOW_START)) {
  86                 WARN_ON(1);
  87                 return NULL;
  88         }
  89
  90         if (addr >= XKVRANGE_VC_SHADOW_OFFSET)
  91                 return (void *)(((addr - XKVRANGE_VC_SHADOW_OFFSET) << KASAN_SHADOW_SCALE_SHIFT) + XKVRANGE_VC_START);
  92         else if (addr >= XKPRANGE_WC_SHADOW_OFFSET)
  93                 return (void *)(((addr - XKPRANGE_WC_SHADOW_OFFSET) << KASAN_SHADOW_SCALE_SHIFT) + XKPRANGE_WC_START);
  94         else if (addr >= XKPRANGE_UC_SHADOW_OFFSET)
  95                 return (void *)(((addr - XKPRANGE_UC_SHADOW_OFFSET) << KASAN_SHADOW_SCALE_SHIFT) + XKPRANGE_UC_START);
  96         else if (addr >= XKPRANGE_CC_SHADOW_OFFSET)
  97                 return (void *)(((addr - XKPRANGE_CC_SHADOW_OFFSET) << KASAN_SHADOW_SCALE_SHIFT) + XKPRANGE_CC_START);
  98         else {
  99                 WARN_ON(1);
 100                 return NULL;
 101         }
 102 }
 103
 104 /*
 105  * Alloc memory for shadow memory page table.
 106  */
 107 static phys_addr_t __init kasan_alloc_zeroed_page(int node)
 108 {
 109         void *p = memblock_alloc_try_nid(PAGE_SIZE, PAGE_SIZE,
 110                                         __pa(MAX_DMA_ADDRESS), MEMBLOCK_ALLOC_ACCESSIBLE, node);
 111         if (!p)
 112                 panic("%s: Failed to allocate %lu bytes align=0x%lx nid=%d from=%llx\n",
 113                         __func__, PAGE_SIZE, PAGE_SIZE, node, __pa(MAX_DMA_ADDRESS));
 114
 115         return __pa(p);
 116 }
 117
 118 static pte_t *__init kasan_pte_offset(pmd_t *pmdp, unsigned long addr, int node, bool early)
 119 {
 120         if (__pmd_none(early, pmdp_get(pmdp))) {
 121                 phys_addr_t pte_phys = early ?
 122                                 __pa_symbol(kasan_early_shadow_pte) : kasan_alloc_zeroed_page(node);
 123                 if (!early)
 124                         memcpy(__va(pte_phys), kasan_early_shadow_pte, sizeof(kasan_early_shadow_pte));
 125                 pmd_populate_kernel(NULL, pmdp, (pte_t *)__va(pte_phys));
 126         }
 127
 128         return pte_offset_kernel(pmdp, addr);
 129 }
 130
 131 static pmd_t *__init kasan_pmd_offset(pud_t *pudp, unsigned long addr, int node, bool early)
 132 {
 133         if (__pud_none(early, pudp_get(pudp))) {
 134                 phys_addr_t pmd_phys = early ?
 135                                 __pa_symbol(kasan_early_shadow_pmd) : kasan_alloc_zeroed_page(node);
 136                 if (!early)
 137                         memcpy(__va(pmd_phys), kasan_early_shadow_pmd, sizeof(kasan_early_shadow_pmd));
 138                 pud_populate(&init_mm, pudp, (pmd_t *)__va(pmd_phys));
 139         }
 140
 141         return pmd_offset(pudp, addr);
 142 }
 143
 144 static pud_t *__init kasan_pud_offset(p4d_t *p4dp, unsigned long addr, int node, bool early)
 145 {
 146         if (__p4d_none(early, p4dp_get(p4dp))) {
 147                 phys_addr_t pud_phys = early ?
 148                         __pa_symbol(kasan_early_shadow_pud) : kasan_alloc_zeroed_page(node);
 149                 if (!early)
 150                         memcpy(__va(pud_phys), kasan_early_shadow_pud, sizeof(kasan_early_shadow_pud));
 151                 p4d_populate(&init_mm, p4dp, (pud_t *)__va(pud_phys));
 152         }
 153
 154         return pud_offset(p4dp, addr);
 155 }
 156
 157 static p4d_t *__init kasan_p4d_offset(pgd_t *pgdp, unsigned long addr, int node, bool early)
 158 {
 159         if (__pgd_none(early, pgdp_get(pgdp))) {
 160                 phys_addr_t p4d_phys = early ?
 161                         __pa_symbol(kasan_early_shadow_p4d) : kasan_alloc_zeroed_page(node);
 162                 if (!early)
 163                         memcpy(__va(p4d_phys), kasan_early_shadow_p4d, sizeof(kasan_early_shadow_p4d));
 164                 pgd_populate(&init_mm, pgdp, (p4d_t *)__va(p4d_phys));
 165         }
 166
 167         return p4d_offset(pgdp, addr);
 168 }
 169
 170 static void __init kasan_pte_populate(pmd_t *pmdp, unsigned long addr,
 171                                       unsigned long end, int node, bool early)
 172 {
 173         unsigned long next;
 174         pte_t *ptep = kasan_pte_offset(pmdp, addr, node, early);
 175
 176         do {
 177                 phys_addr_t page_phys = early ?
 178                                         __pa_symbol(kasan_early_shadow_page)
 179                                               : kasan_alloc_zeroed_page(node);
 180                 next = addr + PAGE_SIZE;
 181                 set_pte(ptep, pfn_pte(__phys_to_pfn(page_phys), PAGE_KERNEL));
 182         } while (ptep++, addr = next, addr != end && __pte_none(early, ptep_get(ptep)));
 183 }
 184
 185 static void __init kasan_pmd_populate(pud_t *pudp, unsigned long addr,
 186                                       unsigned long end, int node, bool early)
 187 {
 188         unsigned long next;
 189         pmd_t *pmdp = kasan_pmd_offset(pudp, addr, node, early);
 190
 191         do {
 192                 next = pmd_addr_end(addr, end);
 193                 kasan_pte_populate(pmdp, addr, next, node, early);
 194         } while (pmdp++, addr = next, addr != end && __pmd_none(early, pmdp_get(pmdp)));
 195 }
 196
 197 static void __init kasan_pud_populate(p4d_t *p4dp, unsigned long addr,
 198                                             unsigned long end, int node, bool early)
 199 {
 200         unsigned long next;
 201         pud_t *pudp = kasan_pud_offset(p4dp, addr, node, early);
 202
 203         do {
 204                 next = pud_addr_end(addr, end);
 205                 kasan_pmd_populate(pudp, addr, next, node, early);
 206         } while (pudp++, addr = next, addr != end && __pud_none(early, READ_ONCE(*pudp)));
 207 }
 208
 209 static void __init kasan_p4d_populate(pgd_t *pgdp, unsigned long addr,
 210                                             unsigned long end, int node, bool early)
 211 {
 212         unsigned long next;
 213         p4d_t *p4dp = kasan_p4d_offset(pgdp, addr, node, early);
 214
 215         do {
 216                 next = p4d_addr_end(addr, end);
 217                 kasan_pud_populate(p4dp, addr, next, node, early);
 218         } while (p4dp++, addr = next, addr != end && __p4d_none(early, READ_ONCE(*p4dp)));
 219 }
 220
 221 static void __init kasan_pgd_populate(unsigned long addr, unsigned long end,
 222                                       int node, bool early)
 223 {
 224         unsigned long next;
 225         pgd_t *pgdp;
 226
 227         pgdp = pgd_offset_k(addr);
 228
 229         do {
 230                 next = pgd_addr_end(addr, end);
 231                 kasan_p4d_populate(pgdp, addr, next, node, early);
 232         } while (pgdp++, addr = next, addr != end);
 233
 234 }
 235
 236 /* Set up full kasan mappings, ensuring that the mapped pages are zeroed */
 237 static void __init kasan_map_populate(unsigned long start, unsigned long end,
 238                                       int node)
 239 {
 240         kasan_pgd_populate(start & PAGE_MASK, PAGE_ALIGN(end), node, false);
 241 }
 242
 243 asmlinkage void __init kasan_early_init(void)
 244 {
 245         BUILD_BUG_ON(!IS_ALIGNED(KASAN_SHADOW_START, PGDIR_SIZE));
 246         BUILD_BUG_ON(!IS_ALIGNED(KASAN_SHADOW_END + 1, PGDIR_SIZE));
 247 }
 248
 249 static inline void kasan_set_pgd(pgd_t *pgdp, pgd_t pgdval)
 250 {
 251         WRITE_ONCE(*pgdp, pgdval);
 252 }
 253
 254 static void __init clear_pgds(unsigned long start, unsigned long end)
 255 {
 256         /*
 257          * Remove references to kasan page tables from
 258          * swapper_pg_dir. pgd_clear() can't be used
 259          * here because it's nop on 2,3-level pagetable setups
 260          */
 261         for (; start < end; start = pgd_addr_end(start, end))
 262                 kasan_set_pgd((pgd_t *)pgd_offset_k(start), __pgd(0));
 263 }
 264
 265 void __init kasan_init(void)
 266 {
 267         u64 i;
 268         phys_addr_t pa_start, pa_end;
 269
 270         /*
 271          * If PGDIR_SIZE is too large for cpu_vabits, KASAN_SHADOW_END will
 272          * overflow UINTPTR_MAX and then looks like a user space address.
 273          * For example, PGDIR_SIZE of CONFIG_4KB_4LEVEL is 2^39, which is too
 274          * large for Loongson-2K series whose cpu_vabits = 39.
 275          */
 276         if (KASAN_SHADOW_END < vm_map_base) {
 277                 pr_warn("PGDIR_SIZE too large for cpu_vabits, KernelAddressSanitizer disabled.\n");
 278                 return;
 279         }
 280
 281         /*
 282          * PGD was populated as invalid_pmd_table or invalid_pud_table
 283          * in pagetable_init() which depends on how many levels of page
 284          * table you are using, but we had to clean the gpd of kasan
 285          * shadow memory, as the pgd value is none-zero.
 286          * The assertion pgd_none is going to be false and the formal populate
 287          * afterwards is not going to create any new pgd at all.
 288          */
 289         memcpy(kasan_pg_dir, swapper_pg_dir, sizeof(kasan_pg_dir));
 290         csr_write64(__pa_symbol(kasan_pg_dir), LOONGARCH_CSR_PGDH);
 291         local_flush_tlb_all();
 292
 293         clear_pgds(KASAN_SHADOW_START, KASAN_SHADOW_END);
 294
 295         /* Maps everything to a single page of zeroes */
 296         kasan_pgd_populate(KASAN_SHADOW_START, KASAN_SHADOW_END, NUMA_NO_NODE, true);
 297
 298         kasan_populate_early_shadow(kasan_mem_to_shadow((void *)VMALLOC_START),
 299                                         kasan_mem_to_shadow((void *)KFENCE_AREA_END));
 300
 301         kasan_early_stage = false;
 302
 303         /* Populate the linear mapping */
 304         for_each_mem_range(i, &pa_start, &pa_end) {
 305                 void *start = (void *)phys_to_virt(pa_start);
 306                 void *end   = (void *)phys_to_virt(pa_end);
 307
 308                 if (start >= end)
 309                         break;
 310
 311                 kasan_map_populate((unsigned long)kasan_mem_to_shadow(start),
 312                         (unsigned long)kasan_mem_to_shadow(end), NUMA_NO_NODE);
 313         }
 314
 315         /* Populate modules mapping */
 316         kasan_map_populate((unsigned long)kasan_mem_to_shadow((void *)MODULES_VADDR),
 317                 (unsigned long)kasan_mem_to_shadow((void *)MODULES_END), NUMA_NO_NODE);
 318         /*
 319          * KAsan may reuse the contents of kasan_early_shadow_pte directly, so we
 320          * should make sure that it maps the zero page read-only.
 321          */
 322         for (i = 0; i < PTRS_PER_PTE; i++)
 323                 set_pte(&kasan_early_shadow_pte[i],
 324                         pfn_pte(__phys_to_pfn(__pa_symbol(kasan_early_shadow_page)), PAGE_KERNEL_RO));
 325
 326         memset(kasan_early_shadow_page, 0, PAGE_SIZE);
 327         csr_write64(__pa_symbol(swapper_pg_dir), LOONGARCH_CSR_PGDH);
 328         local_flush_tlb_all();
 329
 330         /* At this point kasan is fully initialized. Enable error messages */
 331         init_task.kasan_depth = 0;
 332         pr_info("KernelAddressSanitizer initialized.\n");
 333 }