1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2020-2022 Loongson Technology Corporation Limited 4 */ 5 #include <linux/export.h> 6 #include <linux/io.h> 7 #include <linux/memblock.h> 8 #include <linux/mm.h> 9 #include <linux/mman.h> 10 11 #define SHM_ALIGN_MASK (SHMLBA - 1) 12 13 #define COLOUR_ALIGN(addr, pgoff) \ 14 ((((addr) + SHM_ALIGN_MASK) & ~SHM_ALIGN_MASK) \ 15 + (((pgoff) << PAGE_SHIFT) & SHM_ALIGN_MASK)) 16 17 enum mmap_allocation_direction {UP, DOWN}; 18 19 static unsigned long arch_get_unmapped_area_common(struct file *filp, 20 unsigned long addr0, unsigned long len, unsigned long pgoff, 21 unsigned long flags, enum mmap_allocation_direction dir) 22 { 23 struct mm_struct *mm = current->mm; 24 struct vm_area_struct *vma; 25 unsigned long addr = addr0; 26 int do_color_align; 27 struct vm_unmapped_area_info info; 28 29 if (unlikely(len > TASK_SIZE)) 30 return -ENOMEM; 31 32 if (flags & MAP_FIXED) { 33 /* Even MAP_FIXED mappings must reside within TASK_SIZE */ 34 if (TASK_SIZE - len < addr) 35 return -EINVAL; 36 37 /* 38 * We do not accept a shared mapping if it would violate 39 * cache aliasing constraints. 40 */ 41 if ((flags & MAP_SHARED) && 42 ((addr - (pgoff << PAGE_SHIFT)) & SHM_ALIGN_MASK)) 43 return -EINVAL; 44 return addr; 45 } 46 47 do_color_align = 0; 48 if (filp || (flags & MAP_SHARED)) 49 do_color_align = 1; 50 51 /* requesting a specific address */ 52 if (addr) { 53 if (do_color_align) 54 addr = COLOUR_ALIGN(addr, pgoff); 55 else 56 addr = PAGE_ALIGN(addr); 57 58 vma = find_vma(mm, addr); 59 if (TASK_SIZE - len >= addr && 60 (!vma || addr + len <= vm_start_gap(vma))) 61 return addr; 62 } 63 64 info.length = len; 65 info.align_mask = do_color_align ? (PAGE_MASK & SHM_ALIGN_MASK) : 0; 66 info.align_offset = pgoff << PAGE_SHIFT; 67 68 if (dir == DOWN) { 69 info.flags = VM_UNMAPPED_AREA_TOPDOWN; 70 info.low_limit = PAGE_SIZE; 71 info.high_limit = mm->mmap_base; 72 addr = vm_unmapped_area(&info); 73 74 if (!(addr & ~PAGE_MASK)) 75 return addr; 76 77 /* 78 * A failed mmap() very likely causes application failure, 79 * so fall back to the bottom-up function here. This scenario 80 * can happen with large stack limits and large mmap() 81 * allocations. 82 */ 83 } 84 85 info.flags = 0; 86 info.low_limit = mm->mmap_base; 87 info.high_limit = TASK_SIZE; 88 return vm_unmapped_area(&info); 89 } 90 91 unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr0, 92 unsigned long len, unsigned long pgoff, unsigned long flags) 93 { 94 return arch_get_unmapped_area_common(filp, 95 addr0, len, pgoff, flags, UP); 96 } 97 98 /* 99 * There is no need to export this but sched.h declares the function as 100 * extern so making it static here results in an error. 101 */ 102 unsigned long arch_get_unmapped_area_topdown(struct file *filp, 103 unsigned long addr0, unsigned long len, unsigned long pgoff, 104 unsigned long flags) 105 { 106 return arch_get_unmapped_area_common(filp, 107 addr0, len, pgoff, flags, DOWN); 108 } 109 110 int __virt_addr_valid(volatile void *kaddr) 111 { 112 unsigned long vaddr = (unsigned long)kaddr; 113 114 if ((vaddr < PAGE_OFFSET) || (vaddr >= vm_map_base)) 115 return 0; 116 117 return pfn_valid(PFN_DOWN(PHYSADDR(kaddr))); 118 } 119 EXPORT_SYMBOL_GPL(__virt_addr_valid); 120 121 /* 122 * You really shouldn't be using read() or write() on /dev/mem. This might go 123 * away in the future. 124 */ 125 int valid_phys_addr_range(phys_addr_t addr, size_t size) 126 { 127 /* 128 * Check whether addr is covered by a memory region without the 129 * MEMBLOCK_NOMAP attribute, and whether that region covers the 130 * entire range. In theory, this could lead to false negatives 131 * if the range is covered by distinct but adjacent memory regions 132 * that only differ in other attributes. However, few of such 133 * attributes have been defined, and it is debatable whether it 134 * follows that /dev/mem read() calls should be able traverse 135 * such boundaries. 136 */ 137 return memblock_is_region_memory(addr, size) && memblock_is_map_memory(addr); 138 } 139 140 /* 141 * Do not allow /dev/mem mappings beyond the supported physical range. 142 */ 143 int valid_mmap_phys_addr_range(unsigned long pfn, size_t size) 144 { 145 return !(((pfn << PAGE_SHIFT) + size) & ~(GENMASK_ULL(cpu_pabits, 0))); 146 } 147