mm/kasan/init_book3e_64.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /*
0003  * KASAN for 64-bit Book3e powerpc
0004  *
0005  * Copyright 2022, Christophe Leroy, CS GROUP France
0006  */
0007
0008 #define DISABLE_BRANCH_PROFILING
0009
0010 #include <linux/kasan.h>
0011 #include <linux/printk.h>
0012 #include <linux/memblock.h>
0013 #include <linux/set_memory.h>
0014
0015 #include <asm/pgalloc.h>
0016
0017 static inline bool kasan_pud_table(p4d_t p4d)
0018 {
0019     return p4d_page(p4d) == virt_to_page(lm_alias(kasan_early_shadow_pud));
0020 }
0021
0022 static inline bool kasan_pmd_table(pud_t pud)
0023 {
0024     return pud_page(pud) == virt_to_page(lm_alias(kasan_early_shadow_pmd));
0025 }
0026
0027 static inline bool kasan_pte_table(pmd_t pmd)
0028 {
0029     return pmd_page(pmd) == virt_to_page(lm_alias(kasan_early_shadow_pte));
0030 }
0031
0032 static int __init kasan_map_kernel_page(unsigned long ea, unsigned long pa, pgprot_t prot)
0033 {
0034     pgd_t *pgdp;
0035     p4d_t *p4dp;
0036     pud_t *pudp;
0037     pmd_t *pmdp;
0038     pte_t *ptep;
0039
0040     pgdp = pgd_offset_k(ea);
0041     p4dp = p4d_offset(pgdp, ea);
0042     if (kasan_pud_table(*p4dp)) {
0043         pudp = memblock_alloc(PUD_TABLE_SIZE, PUD_TABLE_SIZE);
0044         memcpy(pudp, kasan_early_shadow_pud, PUD_TABLE_SIZE);
0045         p4d_populate(&init_mm, p4dp, pudp);
0046     }
0047     pudp = pud_offset(p4dp, ea);
0048     if (kasan_pmd_table(*pudp)) {
0049         pmdp = memblock_alloc(PMD_TABLE_SIZE, PMD_TABLE_SIZE);
0050         memcpy(pmdp, kasan_early_shadow_pmd, PMD_TABLE_SIZE);
0051         pud_populate(&init_mm, pudp, pmdp);
0052     }
0053     pmdp = pmd_offset(pudp, ea);
0054     if (kasan_pte_table(*pmdp)) {
0055         ptep = memblock_alloc(PTE_TABLE_SIZE, PTE_TABLE_SIZE);
0056         memcpy(ptep, kasan_early_shadow_pte, PTE_TABLE_SIZE);
0057         pmd_populate_kernel(&init_mm, pmdp, ptep);
0058     }
0059     ptep = pte_offset_kernel(pmdp, ea);
0060
0061     __set_pte_at(&init_mm, ea, ptep, pfn_pte(pa >> PAGE_SHIFT, prot), 0);
0062
0063     return 0;
0064 }
0065
0066 static void __init kasan_init_phys_region(void *start, void *end)
0067 {
0068     unsigned long k_start, k_end, k_cur;
0069     void *va;
0070
0071     if (start >= end)
0072         return;
0073
0074     k_start = ALIGN_DOWN((unsigned long)kasan_mem_to_shadow(start), PAGE_SIZE);
0075     k_end = ALIGN((unsigned long)kasan_mem_to_shadow(end), PAGE_SIZE);
0076
0077     va = memblock_alloc(k_end - k_start, PAGE_SIZE);
0078     for (k_cur = k_start; k_cur < k_end; k_cur += PAGE_SIZE, va += PAGE_SIZE)
0079         kasan_map_kernel_page(k_cur, __pa(va), PAGE_KERNEL);
0080 }
0081
0082 void __init kasan_early_init(void)
0083 {
0084     int i;
0085     unsigned long addr;
0086     pgd_t *pgd = pgd_offset_k(KASAN_SHADOW_START);
0087     pte_t zero_pte = pfn_pte(virt_to_pfn(kasan_early_shadow_page), PAGE_KERNEL);
0088
0089     BUILD_BUG_ON(!IS_ALIGNED(KASAN_SHADOW_START, PGDIR_SIZE));
0090     BUILD_BUG_ON(!IS_ALIGNED(KASAN_SHADOW_END, PGDIR_SIZE));
0091
0092     for (i = 0; i < PTRS_PER_PTE; i++)
0093         __set_pte_at(&init_mm, (unsigned long)kasan_early_shadow_page,
0094                  &kasan_early_shadow_pte[i], zero_pte, 0);
0095
0096     for (i = 0; i < PTRS_PER_PMD; i++)
0097         pmd_populate_kernel(&init_mm, &kasan_early_shadow_pmd[i],
0098                     kasan_early_shadow_pte);
0099
0100     for (i = 0; i < PTRS_PER_PUD; i++)
0101         pud_populate(&init_mm, &kasan_early_shadow_pud[i],
0102                  kasan_early_shadow_pmd);
0103
0104     for (addr = KASAN_SHADOW_START; addr != KASAN_SHADOW_END; addr += PGDIR_SIZE)
0105         p4d_populate(&init_mm, p4d_offset(pgd++, addr), kasan_early_shadow_pud);
0106 }
0107
0108 void __init kasan_init(void)
0109 {
0110     phys_addr_t start, end;
0111     u64 i;
0112     pte_t zero_pte = pfn_pte(virt_to_pfn(kasan_early_shadow_page), PAGE_KERNEL_RO);
0113
0114     for_each_mem_range(i, &start, &end)
0115         kasan_init_phys_region((void *)start, (void *)end);
0116
0117     if (IS_ENABLED(CONFIG_KASAN_VMALLOC))
0118         kasan_remove_zero_shadow((void *)VMALLOC_START, VMALLOC_SIZE);
0119
0120     for (i = 0; i < PTRS_PER_PTE; i++)
0121         __set_pte_at(&init_mm, (unsigned long)kasan_early_shadow_page,
0122                  &kasan_early_shadow_pte[i], zero_pte, 0);
0123
0124     flush_tlb_kernel_range(KASAN_SHADOW_START, KASAN_SHADOW_END);
0125
0126     memset(kasan_early_shadow_page, 0, PAGE_SIZE);
0127
0128     /* Enable error messages */
0129     init_task.kasan_depth = 0;
0130     pr_info("KASAN init done\n");
0131 }
0132
0133 void __init kasan_late_init(void) { }