1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com) 4 */ 5 6 #include <linux/stddef.h> 7 #include <linux/module.h> 8 #include <linux/memblock.h> 9 #include <linux/mm.h> 10 #include <linux/swap.h> 11 #include <linux/slab.h> 12 #include <linux/init.h> 13 #include <asm/sections.h> 14 #include <asm/page.h> 15 #include <asm/pgalloc.h> 16 #include <as-layout.h> 17 #include <init.h> 18 #include <kern.h> 19 #include <kern_util.h> 20 #include <mem_user.h> 21 #include <os.h> 22 #include <um_malloc.h> 23 #include <linux/sched/task.h> 24 #include <linux/kasan.h> 25 26 #ifdef CONFIG_KASAN 27 void __init kasan_init(void) 28 { 29 /* 30 * kasan_map_memory will map all of the required address space and 31 * the host machine will allocate physical memory as necessary. 32 */ 33 kasan_map_memory((void *)KASAN_SHADOW_START, KASAN_SHADOW_SIZE); 34 init_task.kasan_depth = 0; 35 /* 36 * Since kasan_init() is called before main(), 37 * KASAN is initialized but the enablement is deferred after 38 * jump_label_init(). See arch_mm_preinit(). 39 */ 40 } 41 42 static void (*kasan_init_ptr)(void) 43 __section(".kasan_init") __used 44 = kasan_init; 45 #endif 46 47 /* allocated in paging_init, zeroed in mem_init, and unchanged thereafter */ 48 unsigned long *empty_zero_page = NULL; 49 EXPORT_SYMBOL(empty_zero_page); 50 51 /* 52 * Initialized during boot, and readonly for initializing page tables 53 * afterwards 54 */ 55 pgd_t swapper_pg_dir[PTRS_PER_PGD]; 56 57 /* Initialized at boot time, and readonly after that */ 58 int kmalloc_ok = 0; 59 60 /* Used during early boot */ 61 static unsigned long brk_end; 62 63 void __init arch_mm_preinit(void) 64 { 65 /* Safe to call after jump_label_init(). Enables KASAN. */ 66 kasan_init_generic(); 67 68 /* clear the zero-page */ 69 memset(empty_zero_page, 0, PAGE_SIZE); 70 71 /* Map in the area just after the brk now that kmalloc is about 72 * to be turned on. 73 */ 74 brk_end = PAGE_ALIGN((unsigned long) sbrk(0)); 75 map_memory(brk_end, __pa(brk_end), uml_reserved - brk_end, 1, 1, 0); 76 memblock_free((void *)brk_end, uml_reserved - brk_end); 77 uml_reserved = brk_end; 78 min_low_pfn = PFN_UP(__pa(uml_reserved)); 79 max_pfn = max_low_pfn; 80 } 81 82 void __init mem_init(void) 83 { 84 kmalloc_ok = 1; 85 } 86 87 void __init paging_init(void) 88 { 89 unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0 }; 90 91 empty_zero_page = (unsigned long *) memblock_alloc_low(PAGE_SIZE, 92 PAGE_SIZE); 93 if (!empty_zero_page) 94 panic("%s: Failed to allocate %lu bytes align=%lx\n", 95 __func__, PAGE_SIZE, PAGE_SIZE); 96 97 max_zone_pfn[ZONE_NORMAL] = high_physmem >> PAGE_SHIFT; 98 free_area_init(max_zone_pfn); 99 } 100 101 /* 102 * This can't do anything because nothing in the kernel image can be freed 103 * since it's not in kernel physical memory. 104 */ 105 106 void free_initmem(void) 107 { 108 } 109 110 /* Allocate and free page tables. */ 111 112 pgd_t *pgd_alloc(struct mm_struct *mm) 113 { 114 pgd_t *pgd = __pgd_alloc(mm, 0); 115 116 if (pgd) 117 memcpy(pgd + USER_PTRS_PER_PGD, 118 swapper_pg_dir + USER_PTRS_PER_PGD, 119 (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t)); 120 121 return pgd; 122 } 123 124 void *uml_kmalloc(int size, int flags) 125 { 126 return kmalloc(size, flags); 127 } 128 129 static const pgprot_t protection_map[16] = { 130 [VM_NONE] = PAGE_NONE, 131 [VM_READ] = PAGE_READONLY, 132 [VM_WRITE] = PAGE_COPY, 133 [VM_WRITE | VM_READ] = PAGE_COPY, 134 [VM_EXEC] = PAGE_READONLY, 135 [VM_EXEC | VM_READ] = PAGE_READONLY, 136 [VM_EXEC | VM_WRITE] = PAGE_COPY, 137 [VM_EXEC | VM_WRITE | VM_READ] = PAGE_COPY, 138 [VM_SHARED] = PAGE_NONE, 139 [VM_SHARED | VM_READ] = PAGE_READONLY, 140 [VM_SHARED | VM_WRITE] = PAGE_SHARED, 141 [VM_SHARED | VM_WRITE | VM_READ] = PAGE_SHARED, 142 [VM_SHARED | VM_EXEC] = PAGE_READONLY, 143 [VM_SHARED | VM_EXEC | VM_READ] = PAGE_READONLY, 144 [VM_SHARED | VM_EXEC | VM_WRITE] = PAGE_SHARED, 145 [VM_SHARED | VM_EXEC | VM_WRITE | VM_READ] = PAGE_SHARED 146 }; 147 DECLARE_VM_GET_PAGE_PROT 148 149 void mark_rodata_ro(void) 150 { 151 unsigned long rodata_start = PFN_ALIGN(__start_rodata); 152 unsigned long rodata_end = PFN_ALIGN(__end_rodata); 153 154 os_protect_memory((void *)rodata_start, rodata_end - rodata_start, 1, 0, 0); 155 } 156