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
arch_get_unmapped_area_common(struct file * filp,unsigned long addr0,unsigned long len,unsigned long pgoff,unsigned long flags,enum mmap_allocation_direction dir)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
arch_get_unmapped_area(struct file * filp,unsigned long addr0,unsigned long len,unsigned long pgoff,unsigned long flags)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 */
arch_get_unmapped_area_topdown(struct file * filp,unsigned long addr0,unsigned long len,unsigned long pgoff,unsigned long flags)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
__virt_addr_valid(volatile void * kaddr)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