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 /* 48 * Initialized during boot, and readonly for initializing page tables 49 * afterwards 50 */ 51 pgd_t swapper_pg_dir[PTRS_PER_PGD]; 52 53 /* Initialized at boot time, and readonly after that */ 54 int kmalloc_ok = 0; 55 56 /* Used during early boot */ 57 static unsigned long brk_end; 58 59 void __init arch_mm_preinit(void) 60 { 61 /* Safe to call after jump_label_init(). Enables KASAN. */ 62 kasan_init_generic(); 63 64 /* Map in the area just after the brk now that kmalloc is about 65 * to be turned on. 66 */ 67 brk_end = PAGE_ALIGN((unsigned long) sbrk(0)); 68 map_memory(brk_end, __pa(brk_end), uml_reserved - brk_end, 1, 1, 0); 69 memblock_free((void *)brk_end, uml_reserved - brk_end); 70 uml_reserved = brk_end; 71 min_low_pfn = PFN_UP(__pa(uml_reserved)); 72 max_pfn = max_low_pfn; 73 } 74 75 void __init mem_init(void) 76 { 77 kmalloc_ok = 1; 78 } 79 80 void __init arch_zone_limits_init(unsigned long *max_zone_pfns) 81 { 82 max_zone_pfns[ZONE_NORMAL] = high_physmem >> PAGE_SHIFT; 83 } 84 85 /* 86 * This can't do anything because nothing in the kernel image can be freed 87 * since it's not in kernel physical memory. 88 */ 89 90 void free_initmem(void) 91 { 92 } 93 94 /* Allocate and free page tables. */ 95 96 pgd_t *pgd_alloc(struct mm_struct *mm) 97 { 98 pgd_t *pgd = __pgd_alloc(mm, 0); 99 100 if (pgd) 101 memcpy(pgd + USER_PTRS_PER_PGD, 102 swapper_pg_dir + USER_PTRS_PER_PGD, 103 (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t)); 104 105 return pgd; 106 } 107 108 void *uml_kmalloc(int size, int flags) 109 { 110 return kmalloc(size, flags); 111 } 112 113 static const pgprot_t protection_map[16] = { 114 [VM_NONE] = PAGE_NONE, 115 [VM_READ] = PAGE_READONLY, 116 [VM_WRITE] = PAGE_COPY, 117 [VM_WRITE | VM_READ] = PAGE_COPY, 118 [VM_EXEC] = PAGE_READONLY, 119 [VM_EXEC | VM_READ] = PAGE_READONLY, 120 [VM_EXEC | VM_WRITE] = PAGE_COPY, 121 [VM_EXEC | VM_WRITE | VM_READ] = PAGE_COPY, 122 [VM_SHARED] = PAGE_NONE, 123 [VM_SHARED | VM_READ] = PAGE_READONLY, 124 [VM_SHARED | VM_WRITE] = PAGE_SHARED, 125 [VM_SHARED | VM_WRITE | VM_READ] = PAGE_SHARED, 126 [VM_SHARED | VM_EXEC] = PAGE_READONLY, 127 [VM_SHARED | VM_EXEC | VM_READ] = PAGE_READONLY, 128 [VM_SHARED | VM_EXEC | VM_WRITE] = PAGE_SHARED, 129 [VM_SHARED | VM_EXEC | VM_WRITE | VM_READ] = PAGE_SHARED 130 }; 131 DECLARE_VM_GET_PAGE_PROT 132 133 void mark_rodata_ro(void) 134 { 135 unsigned long rodata_start = PFN_ALIGN(__start_rodata); 136 unsigned long rodata_end = PFN_ALIGN(__end_rodata); 137 138 os_protect_memory((void *)rodata_start, rodata_end - rodata_start, 1, 0, 0); 139 } 140