arch/riscv/mm/kasan_init.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 // Copyright (C) 2019 Andes Technology Corporation
   3
   4 #include <linux/pfn.h>
   5 #include <linux/init_task.h>
   6 #include <linux/kasan.h>
   7 #include <linux/kernel.h>
   8 #include <linux/memblock.h>
   9 #include <asm/tlbflush.h>
  10 #include <asm/pgtable.h>
  11 #include <asm/fixmap.h>
  12
  13 extern pgd_t early_pg_dir[PTRS_PER_PGD];
  14 asmlinkage void __init kasan_early_init(void)
  15 {
  16         uintptr_t i;
  17         pgd_t *pgd = early_pg_dir + pgd_index(KASAN_SHADOW_START);
  18
  19         for (i = 0; i < PTRS_PER_PTE; ++i)
  20                 set_pte(kasan_early_shadow_pte + i,
  21                         mk_pte(virt_to_page(kasan_early_shadow_page),
  22                                PAGE_KERNEL));
  23
  24         for (i = 0; i < PTRS_PER_PMD; ++i)
  25                 set_pmd(kasan_early_shadow_pmd + i,
  26                         pfn_pmd(PFN_DOWN
  27                                 (__pa((uintptr_t) kasan_early_shadow_pte)),
  28                                 __pgprot(_PAGE_TABLE)));
  29
  30         for (i = KASAN_SHADOW_START; i < KASAN_SHADOW_END;
  31              i += PGDIR_SIZE, ++pgd)
  32                 set_pgd(pgd,
  33                         pfn_pgd(PFN_DOWN
  34                                 (__pa(((uintptr_t) kasan_early_shadow_pmd))),
  35                                 __pgprot(_PAGE_TABLE)));
  36
  37         /* init for swapper_pg_dir */
  38         pgd = pgd_offset_k(KASAN_SHADOW_START);
  39
  40         for (i = KASAN_SHADOW_START; i < KASAN_SHADOW_END;
  41              i += PGDIR_SIZE, ++pgd)
  42                 set_pgd(pgd,
  43                         pfn_pgd(PFN_DOWN
  44                                 (__pa(((uintptr_t) kasan_early_shadow_pmd))),
  45                                 __pgprot(_PAGE_TABLE)));
  46
  47         flush_tlb_all();
  48 }
  49
  50 static void __init populate(void *start, void *end)
  51 {
  52         unsigned long i, offset;
  53         unsigned long vaddr = (unsigned long)start & PAGE_MASK;
  54         unsigned long vend = PAGE_ALIGN((unsigned long)end);
  55         unsigned long n_pages = (vend - vaddr) / PAGE_SIZE;
  56         unsigned long n_ptes =
  57             ((n_pages + PTRS_PER_PTE) & -PTRS_PER_PTE) / PTRS_PER_PTE;
  58         unsigned long n_pmds =
  59             ((n_ptes + PTRS_PER_PMD) & -PTRS_PER_PMD) / PTRS_PER_PMD;
  60
  61         pte_t *pte =
  62             memblock_alloc(n_ptes * PTRS_PER_PTE * sizeof(pte_t), PAGE_SIZE);
  63         pmd_t *pmd =
  64             memblock_alloc(n_pmds * PTRS_PER_PMD * sizeof(pmd_t), PAGE_SIZE);
  65         pgd_t *pgd = pgd_offset_k(vaddr);
  66
  67         for (i = 0; i < n_pages; i++) {
  68                 phys_addr_t phys = memblock_phys_alloc(PAGE_SIZE, PAGE_SIZE);
  69                 set_pte(&pte[i], pfn_pte(PHYS_PFN(phys), PAGE_KERNEL));
  70         }
  71
  72         for (i = 0, offset = 0; i < n_ptes; i++, offset += PTRS_PER_PTE)
  73                 set_pmd(&pmd[i],
  74                         pfn_pmd(PFN_DOWN(__pa(&pte[offset])),
  75                                 __pgprot(_PAGE_TABLE)));
  76
  77         for (i = 0, offset = 0; i < n_pmds; i++, offset += PTRS_PER_PMD)
  78                 set_pgd(&pgd[i],
  79                         pfn_pgd(PFN_DOWN(__pa(&pmd[offset])),
  80                                 __pgprot(_PAGE_TABLE)));
  81
  82         flush_tlb_all();
  83         memset(start, 0, end - start);
  84 }
  85
  86 void __init kasan_init(void)
  87 {
  88         struct memblock_region *reg;
  89         unsigned long i;
  90
  91         kasan_populate_early_shadow((void *)KASAN_SHADOW_START,
  92                                     (void *)kasan_mem_to_shadow((void *)
  93                                                                 VMALLOC_END));
  94
  95         for_each_memblock(memory, reg) {
  96                 void *start = (void *)__va(reg->base);
  97                 void *end = (void *)__va(reg->base + reg->size);
  98
  99                 if (start >= end)
 100                         break;
 101
 102                 populate(kasan_mem_to_shadow(start), kasan_mem_to_shadow(end));
 103         };
 104
 105         for (i = 0; i < PTRS_PER_PTE; i++)
 106                 set_pte(&kasan_early_shadow_pte[i],
 107                         mk_pte(virt_to_page(kasan_early_shadow_page),
 108                                __pgprot(_PAGE_PRESENT | _PAGE_READ |
 109                                         _PAGE_ACCESSED)));
 110
 111         memset(kasan_early_shadow_page, 0, PAGE_SIZE);
 112         init_task.kasan_depth = 0;
 113 }