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 <linux/pgtable.h>
 10#include <asm/tlbflush.h>
 11#include <asm/fixmap.h>
 12
 13extern pgd_t early_pg_dir[PTRS_PER_PGD];
 14asmlinkage 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	local_flush_tlb_all();
 48}
 49
 50static 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	local_flush_tlb_all();
 83	memset(start, 0, end - start);
 84}
 85
 86void __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}