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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
0d55303c | 2 | #include <linux/compat.h> |
1da177e4 LT |
3 | #include <linux/errno.h> |
4 | #include <linux/sched.h> | |
01042607 | 5 | #include <linux/sched/mm.h> |
1da177e4 LT |
6 | #include <linux/syscalls.h> |
7 | #include <linux/mm.h> | |
4e950f6f | 8 | #include <linux/fs.h> |
1da177e4 | 9 | #include <linux/smp.h> |
1da177e4 LT |
10 | #include <linux/sem.h> |
11 | #include <linux/msg.h> | |
12 | #include <linux/shm.h> | |
13 | #include <linux/stat.h> | |
14 | #include <linux/mman.h> | |
15 | #include <linux/file.h> | |
16 | #include <linux/utsname.h> | |
17 | #include <linux/personality.h> | |
cc503c1b | 18 | #include <linux/random.h> |
e9c8abb6 | 19 | #include <linux/uaccess.h> |
910b2c51 | 20 | #include <linux/elf.h> |
1da177e4 | 21 | |
1b028f78 | 22 | #include <asm/elf.h> |
1da177e4 LT |
23 | #include <asm/ia32.h> |
24 | ||
dfb09f9b BP |
25 | /* |
26 | * Align a virtual address to avoid aliasing in the I$ on AMD F15h. | |
dfb09f9b | 27 | */ |
f9902472 | 28 | static unsigned long get_align_mask(void) |
dfb09f9b | 29 | { |
dfb09f9b BP |
30 | /* handle 32- and 64-bit case with a single conditional */ |
31 | if (va_align.flags < 0 || !(va_align.flags & (2 - mmap_is_ia32()))) | |
f9902472 | 32 | return 0; |
dfb09f9b BP |
33 | |
34 | if (!(current->flags & PF_RANDOMIZE)) | |
f9902472 | 35 | return 0; |
dfb09f9b | 36 | |
f9902472 ML |
37 | return va_align.mask; |
38 | } | |
dfb09f9b | 39 | |
4e26d11f HMG |
40 | /* |
41 | * To avoid aliasing in the I$ on AMD F15h, the bits defined by the | |
42 | * va_align.bits, [12:upper_bit), are set to a random value instead of | |
43 | * zeroing them. This random value is computed once per boot. This form | |
44 | * of ASLR is known as "per-boot ASLR". | |
45 | * | |
46 | * To achieve this, the random value is added to the info.align_offset | |
47 | * value before calling vm_unmapped_area() or ORed directly to the | |
48 | * address. | |
49 | */ | |
50 | static unsigned long get_align_bits(void) | |
51 | { | |
52 | return va_align.bits & get_align_mask(); | |
53 | } | |
54 | ||
f9902472 ML |
55 | unsigned long align_vdso_addr(unsigned long addr) |
56 | { | |
57 | unsigned long align_mask = get_align_mask(); | |
4e26d11f HMG |
58 | addr = (addr + align_mask) & ~align_mask; |
59 | return addr | get_align_bits(); | |
dfb09f9b BP |
60 | } |
61 | ||
62 | static int __init control_va_addr_alignment(char *str) | |
63 | { | |
64 | /* guard against enabling this on other CPU families */ | |
65 | if (va_align.flags < 0) | |
66 | return 1; | |
67 | ||
68 | if (*str == 0) | |
69 | return 1; | |
70 | ||
71 | if (*str == '=') | |
72 | str++; | |
73 | ||
74 | if (!strcmp(str, "32")) | |
75 | va_align.flags = ALIGN_VA_32; | |
76 | else if (!strcmp(str, "64")) | |
77 | va_align.flags = ALIGN_VA_64; | |
78 | else if (!strcmp(str, "off")) | |
79 | va_align.flags = 0; | |
80 | else if (!strcmp(str, "on")) | |
81 | va_align.flags = ALIGN_VA_32 | ALIGN_VA_64; | |
82 | else | |
83 | return 0; | |
84 | ||
85 | return 1; | |
86 | } | |
87 | __setup("align_va_addr", control_va_addr_alignment); | |
88 | ||
0ac676fb JB |
89 | SYSCALL_DEFINE6(mmap, unsigned long, addr, unsigned long, len, |
90 | unsigned long, prot, unsigned long, flags, | |
91 | unsigned long, fd, unsigned long, off) | |
1da177e4 | 92 | { |
1da177e4 | 93 | if (off & ~PAGE_MASK) |
91a8f6cb | 94 | return -EINVAL; |
1da177e4 | 95 | |
91a8f6cb | 96 | return ksys_mmap_pgoff(addr, len, prot, flags, fd, off >> PAGE_SHIFT); |
1da177e4 LT |
97 | } |
98 | ||
b569bab7 KS |
99 | static void find_start_end(unsigned long addr, unsigned long flags, |
100 | unsigned long *begin, unsigned long *end) | |
1da177e4 | 101 | { |
a846446b | 102 | if (!in_32bit_syscall() && (flags & MAP_32BIT)) { |
1da177e4 LT |
103 | /* This is usually used needed to map code in small |
104 | model, so it needs to be in the first 31bit. Limit | |
105 | it to that. This means we need to move the | |
106 | unmapped base down for this case. This can give | |
107 | conflicts with the heap, but we assume that glibc | |
108 | malloc knows how to fall back to mmap. Give it 1GB | |
e9c8abb6 GP |
109 | of playground for now. -AK */ |
110 | *begin = 0x40000000; | |
111 | *end = 0x80000000; | |
cc503c1b | 112 | if (current->flags & PF_RANDOMIZE) { |
9c6f0902 | 113 | *begin = randomize_page(*begin, 0x02000000); |
cc503c1b | 114 | } |
1b028f78 | 115 | return; |
84929801 | 116 | } |
1b028f78 DS |
117 | |
118 | *begin = get_mmap_base(1); | |
a846446b | 119 | if (in_32bit_syscall()) |
b569bab7 KS |
120 | *end = task_size_32bit(); |
121 | else | |
122 | *end = task_size_64bit(addr > DEFAULT_MAP_WINDOW); | |
e9c8abb6 | 123 | } |
1da177e4 LT |
124 | |
125 | unsigned long | |
126 | arch_get_unmapped_area(struct file *filp, unsigned long addr, | |
127 | unsigned long len, unsigned long pgoff, unsigned long flags) | |
128 | { | |
129 | struct mm_struct *mm = current->mm; | |
130 | struct vm_area_struct *vma; | |
f9902472 | 131 | struct vm_unmapped_area_info info; |
1da177e4 | 132 | unsigned long begin, end; |
e9c8abb6 | 133 | |
11300a64 BH |
134 | if (flags & MAP_FIXED) |
135 | return addr; | |
136 | ||
b569bab7 | 137 | find_start_end(addr, flags, &begin, &end); |
1da177e4 LT |
138 | |
139 | if (len > end) | |
140 | return -ENOMEM; | |
141 | ||
142 | if (addr) { | |
143 | addr = PAGE_ALIGN(addr); | |
144 | vma = find_vma(mm, addr); | |
145 | if (end - len >= addr && | |
1be7107f | 146 | (!vma || addr + len <= vm_start_gap(vma))) |
1da177e4 LT |
147 | return addr; |
148 | } | |
1363c3cd | 149 | |
f9902472 ML |
150 | info.flags = 0; |
151 | info.length = len; | |
152 | info.low_limit = begin; | |
153 | info.high_limit = end; | |
4e26d11f | 154 | info.align_mask = 0; |
7d025059 | 155 | info.align_offset = pgoff << PAGE_SHIFT; |
4e26d11f HMG |
156 | if (filp) { |
157 | info.align_mask = get_align_mask(); | |
158 | info.align_offset += get_align_bits(); | |
159 | } | |
f9902472 | 160 | return vm_unmapped_area(&info); |
1da177e4 LT |
161 | } |
162 | ||
cc503c1b JK |
163 | unsigned long |
164 | arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, | |
165 | const unsigned long len, const unsigned long pgoff, | |
166 | const unsigned long flags) | |
167 | { | |
168 | struct vm_area_struct *vma; | |
169 | struct mm_struct *mm = current->mm; | |
f9902472 ML |
170 | unsigned long addr = addr0; |
171 | struct vm_unmapped_area_info info; | |
cc503c1b JK |
172 | |
173 | /* requested length too big for entire address space */ | |
174 | if (len > TASK_SIZE) | |
175 | return -ENOMEM; | |
176 | ||
1e0f25db | 177 | /* No address checking. See comment at mmap_address_hint_valid() */ |
cc503c1b JK |
178 | if (flags & MAP_FIXED) |
179 | return addr; | |
180 | ||
e3e81aca | 181 | /* for MAP_32BIT mappings we force the legacy mmap base */ |
a846446b | 182 | if (!in_32bit_syscall() && (flags & MAP_32BIT)) |
cc503c1b JK |
183 | goto bottomup; |
184 | ||
185 | /* requesting a specific address */ | |
186 | if (addr) { | |
1e0f25db KS |
187 | addr &= PAGE_MASK; |
188 | if (!mmap_address_hint_valid(addr, len)) | |
189 | goto get_unmapped_area; | |
190 | ||
cc503c1b | 191 | vma = find_vma(mm, addr); |
1e0f25db | 192 | if (!vma || addr + len <= vm_start_gap(vma)) |
cc503c1b JK |
193 | return addr; |
194 | } | |
1e0f25db | 195 | get_unmapped_area: |
cc503c1b | 196 | |
f9902472 ML |
197 | info.flags = VM_UNMAPPED_AREA_TOPDOWN; |
198 | info.length = len; | |
199 | info.low_limit = PAGE_SIZE; | |
1b028f78 | 200 | info.high_limit = get_mmap_base(0); |
b569bab7 KS |
201 | |
202 | /* | |
203 | * If hint address is above DEFAULT_MAP_WINDOW, look for unmapped area | |
204 | * in the full address space. | |
205 | * | |
a846446b DS |
206 | * !in_32bit_syscall() check to avoid high addresses for x32 |
207 | * (and make it no op on native i386). | |
b569bab7 | 208 | */ |
a846446b | 209 | if (addr > DEFAULT_MAP_WINDOW && !in_32bit_syscall()) |
b569bab7 KS |
210 | info.high_limit += TASK_SIZE_MAX - DEFAULT_MAP_WINDOW; |
211 | ||
4e26d11f | 212 | info.align_mask = 0; |
7d025059 | 213 | info.align_offset = pgoff << PAGE_SHIFT; |
4e26d11f HMG |
214 | if (filp) { |
215 | info.align_mask = get_align_mask(); | |
216 | info.align_offset += get_align_bits(); | |
217 | } | |
f9902472 ML |
218 | addr = vm_unmapped_area(&info); |
219 | if (!(addr & ~PAGE_MASK)) | |
220 | return addr; | |
221 | VM_BUG_ON(addr != -ENOMEM); | |
b716ad95 | 222 | |
cc503c1b JK |
223 | bottomup: |
224 | /* | |
225 | * A failed mmap() very likely causes application failure, | |
226 | * so fall back to the bottom-up function here. This scenario | |
227 | * can happen with large stack limits and large mmap() | |
228 | * allocations. | |
229 | */ | |
f9902472 | 230 | return arch_get_unmapped_area(filp, addr0, len, pgoff, flags); |
cc503c1b | 231 | } |