init_book3e_64.c

  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * KASAN for 64-bit Book3e powerpc
  4 *
  5 * Copyright 2022, Christophe Leroy, CS GROUP France
  6 */
  7
  8#define DISABLE_BRANCH_PROFILING
  9
 10#include <linux/kasan.h>
 11#include <linux/printk.h>
 12#include <linux/memblock.h>
 13#include <linux/set_memory.h>
 14
 15#include <asm/pgalloc.h>
 16
 17static inline bool kasan_pud_table(p4d_t p4d)
 18{
 19	return p4d_page(p4d) == virt_to_page(lm_alias(kasan_early_shadow_pud));
 20}
 21
 22static inline bool kasan_pmd_table(pud_t pud)
 23{
 24	return pud_page(pud) == virt_to_page(lm_alias(kasan_early_shadow_pmd));
 25}
 26
 27static inline bool kasan_pte_table(pmd_t pmd)
 28{
 29	return pmd_page(pmd) == virt_to_page(lm_alias(kasan_early_shadow_pte));
 30}
 31
 32static int __init kasan_map_kernel_page(unsigned long ea, unsigned long pa, pgprot_t prot)
 33{
 34	pgd_t *pgdp;
 35	p4d_t *p4dp;
 36	pud_t *pudp;
 37	pmd_t *pmdp;
 38	pte_t *ptep;
 39
 40	pgdp = pgd_offset_k(ea);
 41	p4dp = p4d_offset(pgdp, ea);
 42	if (kasan_pud_table(*p4dp)) {
 43		pudp = memblock_alloc_or_panic(PUD_TABLE_SIZE, PUD_TABLE_SIZE);
 44		memcpy(pudp, kasan_early_shadow_pud, PUD_TABLE_SIZE);
 45		p4d_populate(&init_mm, p4dp, pudp);
 46	}
 47	pudp = pud_offset(p4dp, ea);
 48	if (kasan_pmd_table(*pudp)) {
 49		pmdp = memblock_alloc_or_panic(PMD_TABLE_SIZE, PMD_TABLE_SIZE);
 50		memcpy(pmdp, kasan_early_shadow_pmd, PMD_TABLE_SIZE);
 51		pud_populate(&init_mm, pudp, pmdp);
 52	}
 53	pmdp = pmd_offset(pudp, ea);
 54	if (kasan_pte_table(*pmdp)) {
 55		ptep = memblock_alloc_or_panic(PTE_TABLE_SIZE, PTE_TABLE_SIZE);
 56		memcpy(ptep, kasan_early_shadow_pte, PTE_TABLE_SIZE);
 57		pmd_populate_kernel(&init_mm, pmdp, ptep);
 58	}
 59	ptep = pte_offset_kernel(pmdp, ea);
 60
 61	__set_pte_at(&init_mm, ea, ptep, pfn_pte(pa >> PAGE_SHIFT, prot), 0);
 62
 63	return 0;
 64}
 65
 66static void __init kasan_init_phys_region(void *start, void *end)
 67{
 68	unsigned long k_start, k_end, k_cur;
 69	void *va;
 70
 71	if (start >= end)
 72		return;
 73
 74	k_start = ALIGN_DOWN((unsigned long)kasan_mem_to_shadow(start), PAGE_SIZE);
 75	k_end = ALIGN((unsigned long)kasan_mem_to_shadow(end), PAGE_SIZE);
 76
 77	va = memblock_alloc_or_panic(k_end - k_start, PAGE_SIZE);
 78	for (k_cur = k_start; k_cur < k_end; k_cur += PAGE_SIZE, va += PAGE_SIZE)
 79		kasan_map_kernel_page(k_cur, __pa(va), PAGE_KERNEL);
 80}
 81
 82void __init kasan_early_init(void)
 83{
 84	int i;
 85	unsigned long addr;
 86	pgd_t *pgd = pgd_offset_k(KASAN_SHADOW_START);
 87	pte_t zero_pte = pfn_pte(virt_to_pfn(kasan_early_shadow_page), PAGE_KERNEL);
 88
 89	BUILD_BUG_ON(!IS_ALIGNED(KASAN_SHADOW_START, PGDIR_SIZE));
 90	BUILD_BUG_ON(!IS_ALIGNED(KASAN_SHADOW_END, PGDIR_SIZE));
 91
 92	for (i = 0; i < PTRS_PER_PTE; i++)
 93		__set_pte_at(&init_mm, (unsigned long)kasan_early_shadow_page,
 94			     &kasan_early_shadow_pte[i], zero_pte, 0);
 95
 96	for (i = 0; i < PTRS_PER_PMD; i++)
 97		pmd_populate_kernel(&init_mm, &kasan_early_shadow_pmd[i],
 98				    kasan_early_shadow_pte);
 99
100	for (i = 0; i < PTRS_PER_PUD; i++)
101		pud_populate(&init_mm, &kasan_early_shadow_pud[i],
102			     kasan_early_shadow_pmd);
103
104	for (addr = KASAN_SHADOW_START; addr != KASAN_SHADOW_END; addr += PGDIR_SIZE)
105		p4d_populate(&init_mm, p4d_offset(pgd++, addr), kasan_early_shadow_pud);
106}
107
108void __init kasan_init(void)
109{
110	phys_addr_t start, end;
111	u64 i;
112	pte_t zero_pte = pfn_pte(virt_to_pfn(kasan_early_shadow_page), PAGE_KERNEL_RO);
113
114	for_each_mem_range(i, &start, &end)
115		kasan_init_phys_region(phys_to_virt(start), phys_to_virt(end));
116
117	if (IS_ENABLED(CONFIG_KASAN_VMALLOC))
118		kasan_remove_zero_shadow((void *)VMALLOC_START, VMALLOC_SIZE);
119
120	for (i = 0; i < PTRS_PER_PTE; i++)
121		__set_pte_at(&init_mm, (unsigned long)kasan_early_shadow_page,
122			     &kasan_early_shadow_pte[i], zero_pte, 0);
123
124	flush_tlb_kernel_range(KASAN_SHADOW_START, KASAN_SHADOW_END);
125
126	memset(kasan_early_shadow_page, 0, PAGE_SIZE);
127
128	/* Enable error messages */
129	init_task.kasan_depth = 0;
130	kasan_init_generic();
131}
132
133void __init kasan_late_init(void) { }