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(__pa((uintptr_t)kasan_early_shadow_pte)),
  27                         __pgprot(_PAGE_TABLE)));
  28
  29         for (i = KASAN_SHADOW_START; i < KASAN_SHADOW_END;
  30              i += PGDIR_SIZE, ++pgd)
  31                 set_pgd(pgd,
  32                  pfn_pgd(PFN_DOWN(__pa(((uintptr_t)kasan_early_shadow_pmd))),
  33                         __pgprot(_PAGE_TABLE)));
  34
  35         /* init for swapper_pg_dir */
  36         pgd = pgd_offset_k(KASAN_SHADOW_START);
  37
  38         for (i = KASAN_SHADOW_START; i < KASAN_SHADOW_END;
  39              i += PGDIR_SIZE, ++pgd)
  40                 set_pgd(pgd,
  41                  pfn_pgd(PFN_DOWN(__pa(((uintptr_t)kasan_early_shadow_pmd))),
  42                         __pgprot(_PAGE_TABLE)));
  43
  44         flush_tlb_all();
  45 }
  46
  47 static void __init populate(void *start, void *end)
  48 {
  49         unsigned long i;
  50         unsigned long vaddr = (unsigned long)start & PAGE_MASK;
  51         unsigned long vend = PAGE_ALIGN((unsigned long)end);
  52         unsigned long n_pages = (vend - vaddr) / PAGE_SIZE;
  53         unsigned long n_pmds =
  54                 (n_pages % PTRS_PER_PTE) ? n_pages / PTRS_PER_PTE + 1 :
  55                                                 n_pages / PTRS_PER_PTE;
  56         pgd_t *pgd = pgd_offset_k(vaddr);
  57         pmd_t *pmd = memblock_alloc(n_pmds * sizeof(pmd_t), PAGE_SIZE);
  58         pte_t *pte = memblock_alloc(n_pages * sizeof(pte_t), PAGE_SIZE);
  59
  60         for (i = 0; i < n_pages; i++) {
  61                 phys_addr_t phys = memblock_phys_alloc(PAGE_SIZE, PAGE_SIZE);
  62
  63                 set_pte(pte + i, pfn_pte(PHYS_PFN(phys), PAGE_KERNEL));
  64         }
  65
  66         for (i = 0; i < n_pmds; ++pgd, i += PTRS_PER_PMD)
  67                 set_pgd(pgd, pfn_pgd(PFN_DOWN(__pa(((uintptr_t)(pmd + i)))),
  68                                 __pgprot(_PAGE_TABLE)));
  69
  70         for (i = 0; i < n_pages; ++pmd, i += PTRS_PER_PTE)
  71                 set_pmd(pmd, pfn_pmd(PFN_DOWN(__pa((uintptr_t)(pte + i))),
  72                                 __pgprot(_PAGE_TABLE)));
  73
  74         flush_tlb_all();
  75         memset(start, 0, end - start);
  76 }
  77
  78 void __init kasan_init(void)
  79 {
  80         struct memblock_region *reg;
  81         unsigned long i;
  82
  83         kasan_populate_early_shadow((void *)KASAN_SHADOW_START,
  84                         (void *)kasan_mem_to_shadow((void *)VMALLOC_END));
  85
  86         for_each_memblock(memory, reg) {
  87                 void *start = (void *)__va(reg->base);
  88                 void *end = (void *)__va(reg->base + reg->size);
  89
  90                 if (start >= end)
  91                         break;
  92
  93                 populate(kasan_mem_to_shadow(start),
  94                          kasan_mem_to_shadow(end));
  95         };
  96
  97         for (i = 0; i < PTRS_PER_PTE; i++)
  98                 set_pte(&kasan_early_shadow_pte[i],
  99                         mk_pte(virt_to_page(kasan_early_shadow_page),
 100                         __pgprot(_PAGE_PRESENT | _PAGE_READ | _PAGE_ACCESSED)));
 101
 102         memset(kasan_early_shadow_page, 0, PAGE_SIZE);
 103         init_task.kasan_depth = 0;
 104 }