1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2020-2022 Loongson Technology Corporation Limited 4 */ 5 #include <linux/compiler.h> 6 #include <linux/elf-randomize.h> 7 #include <linux/errno.h> 8 #include <linux/mm.h> 9 #include <linux/mman.h> 10 #include <linux/export.h> 11 #include <linux/personality.h> 12 #include <linux/random.h> 13 #include <linux/sched/signal.h> 14 #include <linux/sched/mm.h> 15 16 unsigned long shm_align_mask = PAGE_SIZE - 1; /* Sane caches */ 17 EXPORT_SYMBOL(shm_align_mask); 18 19 #define COLOUR_ALIGN(addr, pgoff) \ 20 ((((addr) + shm_align_mask) & ~shm_align_mask) + \ 21 (((pgoff) << PAGE_SHIFT) & shm_align_mask)) 22 23 enum mmap_allocation_direction {UP, DOWN}; 24 25 static unsigned long arch_get_unmapped_area_common(struct file *filp, 26 unsigned long addr0, unsigned long len, unsigned long pgoff, 27 unsigned long flags, enum mmap_allocation_direction dir) 28 { 29 struct mm_struct *mm = current->mm; 30 struct vm_area_struct *vma; 31 unsigned long addr = addr0; 32 int do_color_align; 33 struct vm_unmapped_area_info info; 34 35 if (unlikely(len > TASK_SIZE)) 36 return -ENOMEM; 37 38 if (flags & MAP_FIXED) { 39 /* Even MAP_FIXED mappings must reside within TASK_SIZE */ 40 if (TASK_SIZE - len < addr) 41 return -EINVAL; 42 43 /* 44 * We do not accept a shared mapping if it would violate 45 * cache aliasing constraints. 46 */ 47 if ((flags & MAP_SHARED) && 48 ((addr - (pgoff << PAGE_SHIFT)) & shm_align_mask)) 49 return -EINVAL; 50 return addr; 51 } 52 53 do_color_align = 0; 54 if (filp || (flags & MAP_SHARED)) 55 do_color_align = 1; 56 57 /* requesting a specific address */ 58 if (addr) { 59 if (do_color_align) 60 addr = COLOUR_ALIGN(addr, pgoff); 61 else 62 addr = PAGE_ALIGN(addr); 63 64 vma = find_vma(mm, addr); 65 if (TASK_SIZE - len >= addr && 66 (!vma || addr + len <= vm_start_gap(vma))) 67 return addr; 68 } 69 70 info.length = len; 71 info.align_mask = do_color_align ? (PAGE_MASK & shm_align_mask) : 0; 72 info.align_offset = pgoff << PAGE_SHIFT; 73 74 if (dir == DOWN) { 75 info.flags = VM_UNMAPPED_AREA_TOPDOWN; 76 info.low_limit = PAGE_SIZE; 77 info.high_limit = mm->mmap_base; 78 addr = vm_unmapped_area(&info); 79 80 if (!(addr & ~PAGE_MASK)) 81 return addr; 82 83 /* 84 * A failed mmap() very likely causes application failure, 85 * so fall back to the bottom-up function here. This scenario 86 * can happen with large stack limits and large mmap() 87 * allocations. 88 */ 89 } 90 91 info.flags = 0; 92 info.low_limit = mm->mmap_base; 93 info.high_limit = TASK_SIZE; 94 return vm_unmapped_area(&info); 95 } 96 97 unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr0, 98 unsigned long len, unsigned long pgoff, unsigned long flags) 99 { 100 return arch_get_unmapped_area_common(filp, 101 addr0, len, pgoff, flags, UP); 102 } 103 104 /* 105 * There is no need to export this but sched.h declares the function as 106 * extern so making it static here results in an error. 107 */ 108 unsigned long arch_get_unmapped_area_topdown(struct file *filp, 109 unsigned long addr0, unsigned long len, unsigned long pgoff, 110 unsigned long flags) 111 { 112 return arch_get_unmapped_area_common(filp, 113 addr0, len, pgoff, flags, DOWN); 114 } 115 116 int __virt_addr_valid(volatile void *kaddr) 117 { 118 unsigned long vaddr = (unsigned long)kaddr; 119 120 if ((vaddr < PAGE_OFFSET) || (vaddr >= vm_map_base)) 121 return 0; 122 123 return pfn_valid(PFN_DOWN(virt_to_phys(kaddr))); 124 } 125 EXPORT_SYMBOL_GPL(__virt_addr_valid); 126