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1// SPDX-License-Identifier: GPL-2.0
2#include <linux/compat.h>
3#include <linux/errno.h>
4#include <linux/sched.h>
5#include <linux/sched/mm.h>
6#include <linux/syscalls.h>
7#include <linux/mm.h>
8#include <linux/fs.h>
9#include <linux/smp.h>
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>
18#include <linux/random.h>
19#include <linux/uaccess.h>
20#include <linux/elf.h>
21#include <linux/hugetlb.h>
22
23#include <asm/elf.h>
24#include <asm/ia32.h>
25
26/*
27 * Align a virtual address to avoid aliasing in the I$ on AMD F15h.
28 */
29static unsigned long get_align_mask(struct file *filp)
30{
31 if (filp && is_file_hugepages(filp))
32 return huge_page_mask_align(filp);
33 /* handle 32- and 64-bit case with a single conditional */
34 if (va_align.flags < 0 || !(va_align.flags & (2 - mmap_is_ia32())))
35 return 0;
36
37 if (!(current->flags & PF_RANDOMIZE))
38 return 0;
39
40 return va_align.mask;
41}
42
43/*
44 * To avoid aliasing in the I$ on AMD F15h, the bits defined by the
45 * va_align.bits, [12:upper_bit), are set to a random value instead of
46 * zeroing them. This random value is computed once per boot. This form
47 * of ASLR is known as "per-boot ASLR".
48 *
49 * To achieve this, the random value is added to the info.align_offset
50 * value before calling vm_unmapped_area() or ORed directly to the
51 * address.
52 */
53static unsigned long get_align_bits(void)
54{
55 return va_align.bits & get_align_mask(NULL);
56}
57
58static int __init control_va_addr_alignment(char *str)
59{
60 /* guard against enabling this on other CPU families */
61 if (va_align.flags < 0)
62 return 1;
63
64 if (*str == 0)
65 return 1;
66
67 if (!strcmp(str, "32"))
68 va_align.flags = ALIGN_VA_32;
69 else if (!strcmp(str, "64"))
70 va_align.flags = ALIGN_VA_64;
71 else if (!strcmp(str, "off"))
72 va_align.flags = 0;
73 else if (!strcmp(str, "on"))
74 va_align.flags = ALIGN_VA_32 | ALIGN_VA_64;
75 else
76 pr_warn("invalid option value: 'align_va_addr=%s'\n", str);
77
78 return 1;
79}
80__setup("align_va_addr=", control_va_addr_alignment);
81
82SYSCALL_DEFINE6(mmap, unsigned long, addr, unsigned long, len,
83 unsigned long, prot, unsigned long, flags,
84 unsigned long, fd, unsigned long, off)
85{
86 if (off & ~PAGE_MASK)
87 return -EINVAL;
88
89 return ksys_mmap_pgoff(addr, len, prot, flags, fd, off >> PAGE_SHIFT);
90}
91
92static void find_start_end(unsigned long addr, unsigned long flags,
93 unsigned long *begin, unsigned long *end)
94{
95 if (!in_32bit_syscall() && (flags & MAP_32BIT)) {
96 /* This is usually used needed to map code in small
97 model, so it needs to be in the first 31bit. Limit
98 it to that. This means we need to move the
99 unmapped base down for this case. This can give
100 conflicts with the heap, but we assume that glibc
101 malloc knows how to fall back to mmap. Give it 1GB
102 of playground for now. -AK */
103 *begin = 0x40000000;
104 *end = 0x80000000;
105 if (current->flags & PF_RANDOMIZE) {
106 *begin = randomize_page(*begin, 0x02000000);
107 }
108 return;
109 }
110
111 *begin = get_mmap_base(1);
112 if (in_32bit_syscall())
113 *end = task_size_32bit();
114 else
115 *end = task_size_64bit(addr > DEFAULT_MAP_WINDOW);
116}
117
118static inline unsigned long stack_guard_placement(vm_flags_t vm_flags)
119{
120 if (vm_flags & VM_SHADOW_STACK)
121 return PAGE_SIZE;
122
123 return 0;
124}
125
126unsigned long
127arch_get_unmapped_area(struct file *filp, unsigned long addr, unsigned long len,
128 unsigned long pgoff, unsigned long flags, vm_flags_t vm_flags)
129{
130 struct mm_struct *mm = current->mm;
131 struct vm_area_struct *vma;
132 struct vm_unmapped_area_info info = {};
133 unsigned long begin, end;
134
135 if (flags & MAP_FIXED)
136 return addr;
137
138 find_start_end(addr, flags, &begin, &end);
139
140 if (len > end)
141 return -ENOMEM;
142
143 if (addr) {
144 addr = PAGE_ALIGN(addr);
145 vma = find_vma(mm, addr);
146 if (end - len >= addr &&
147 (!vma || addr + len <= vm_start_gap(vma)))
148 return addr;
149 }
150
151 info.length = len;
152 info.low_limit = begin;
153 info.high_limit = end;
154 if (!(filp && is_file_hugepages(filp))) {
155 info.align_offset = pgoff << PAGE_SHIFT;
156 info.start_gap = stack_guard_placement(vm_flags);
157 }
158 if (filp) {
159 info.align_mask = get_align_mask(filp);
160 info.align_offset += get_align_bits();
161 }
162
163 return vm_unmapped_area(&info);
164}
165
166unsigned long
167arch_get_unmapped_area_topdown(struct file *filp, unsigned long addr0,
168 unsigned long len, unsigned long pgoff,
169 unsigned long flags, vm_flags_t vm_flags)
170{
171 struct vm_area_struct *vma;
172 struct mm_struct *mm = current->mm;
173 unsigned long addr = addr0;
174 struct vm_unmapped_area_info info = {};
175
176 /* requested length too big for entire address space */
177 if (len > TASK_SIZE)
178 return -ENOMEM;
179
180 /* No address checking. See comment at mmap_address_hint_valid() */
181 if (flags & MAP_FIXED)
182 return addr;
183
184 /* for MAP_32BIT mappings we force the legacy mmap base */
185 if (!in_32bit_syscall() && (flags & MAP_32BIT))
186 goto bottomup;
187
188 /* requesting a specific address */
189 if (addr) {
190 addr &= PAGE_MASK;
191 if (!mmap_address_hint_valid(addr, len))
192 goto get_unmapped_area;
193
194 vma = find_vma(mm, addr);
195 if (!vma || addr + len <= vm_start_gap(vma))
196 return addr;
197 }
198get_unmapped_area:
199
200 info.flags = VM_UNMAPPED_AREA_TOPDOWN;
201 info.length = len;
202 if (!in_32bit_syscall() && (flags & MAP_ABOVE4G))
203 info.low_limit = SZ_4G;
204 else
205 info.low_limit = PAGE_SIZE;
206
207 info.high_limit = get_mmap_base(0);
208 if (!(filp && is_file_hugepages(filp))) {
209 info.start_gap = stack_guard_placement(vm_flags);
210 info.align_offset = pgoff << PAGE_SHIFT;
211 }
212
213 /*
214 * If hint address is above DEFAULT_MAP_WINDOW, look for unmapped area
215 * in the full address space.
216 *
217 * !in_32bit_syscall() check to avoid high addresses for x32
218 * (and make it no op on native i386).
219 */
220 if (addr > DEFAULT_MAP_WINDOW && !in_32bit_syscall())
221 info.high_limit += TASK_SIZE_MAX - DEFAULT_MAP_WINDOW;
222
223 if (filp) {
224 info.align_mask = get_align_mask(filp);
225 info.align_offset += get_align_bits();
226 }
227 addr = vm_unmapped_area(&info);
228 if (!(addr & ~PAGE_MASK))
229 return addr;
230 VM_BUG_ON(addr != -ENOMEM);
231
232bottomup:
233 /*
234 * A failed mmap() very likely causes application failure,
235 * so fall back to the bottom-up function here. This scenario
236 * can happen with large stack limits and large mmap()
237 * allocations.
238 */
239 return arch_get_unmapped_area(filp, addr0, len, pgoff, flags, 0);
240}
1#include <linux/errno.h>
2#include <linux/sched.h>
3#include <linux/syscalls.h>
4#include <linux/mm.h>
5#include <linux/fs.h>
6#include <linux/smp.h>
7#include <linux/sem.h>
8#include <linux/msg.h>
9#include <linux/shm.h>
10#include <linux/stat.h>
11#include <linux/mman.h>
12#include <linux/file.h>
13#include <linux/utsname.h>
14#include <linux/personality.h>
15#include <linux/random.h>
16#include <linux/uaccess.h>
17
18#include <asm/ia32.h>
19#include <asm/syscalls.h>
20
21SYSCALL_DEFINE6(mmap, unsigned long, addr, unsigned long, len,
22 unsigned long, prot, unsigned long, flags,
23 unsigned long, fd, unsigned long, off)
24{
25 long error;
26 error = -EINVAL;
27 if (off & ~PAGE_MASK)
28 goto out;
29
30 error = sys_mmap_pgoff(addr, len, prot, flags, fd, off >> PAGE_SHIFT);
31out:
32 return error;
33}
34
35static void find_start_end(unsigned long flags, unsigned long *begin,
36 unsigned long *end)
37{
38 if (!test_thread_flag(TIF_IA32) && (flags & MAP_32BIT)) {
39 unsigned long new_begin;
40 /* This is usually used needed to map code in small
41 model, so it needs to be in the first 31bit. Limit
42 it to that. This means we need to move the
43 unmapped base down for this case. This can give
44 conflicts with the heap, but we assume that glibc
45 malloc knows how to fall back to mmap. Give it 1GB
46 of playground for now. -AK */
47 *begin = 0x40000000;
48 *end = 0x80000000;
49 if (current->flags & PF_RANDOMIZE) {
50 new_begin = randomize_range(*begin, *begin + 0x02000000, 0);
51 if (new_begin)
52 *begin = new_begin;
53 }
54 } else {
55 *begin = TASK_UNMAPPED_BASE;
56 *end = TASK_SIZE;
57 }
58}
59
60unsigned long
61arch_get_unmapped_area(struct file *filp, unsigned long addr,
62 unsigned long len, unsigned long pgoff, unsigned long flags)
63{
64 struct mm_struct *mm = current->mm;
65 struct vm_area_struct *vma;
66 unsigned long start_addr;
67 unsigned long begin, end;
68
69 if (flags & MAP_FIXED)
70 return addr;
71
72 find_start_end(flags, &begin, &end);
73
74 if (len > end)
75 return -ENOMEM;
76
77 if (addr) {
78 addr = PAGE_ALIGN(addr);
79 vma = find_vma(mm, addr);
80 if (end - len >= addr &&
81 (!vma || addr + len <= vma->vm_start))
82 return addr;
83 }
84 if (((flags & MAP_32BIT) || test_thread_flag(TIF_IA32))
85 && len <= mm->cached_hole_size) {
86 mm->cached_hole_size = 0;
87 mm->free_area_cache = begin;
88 }
89 addr = mm->free_area_cache;
90 if (addr < begin)
91 addr = begin;
92 start_addr = addr;
93
94full_search:
95 for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
96 /* At this point: (!vma || addr < vma->vm_end). */
97 if (end - len < addr) {
98 /*
99 * Start a new search - just in case we missed
100 * some holes.
101 */
102 if (start_addr != begin) {
103 start_addr = addr = begin;
104 mm->cached_hole_size = 0;
105 goto full_search;
106 }
107 return -ENOMEM;
108 }
109 if (!vma || addr + len <= vma->vm_start) {
110 /*
111 * Remember the place where we stopped the search:
112 */
113 mm->free_area_cache = addr + len;
114 return addr;
115 }
116 if (addr + mm->cached_hole_size < vma->vm_start)
117 mm->cached_hole_size = vma->vm_start - addr;
118
119 addr = vma->vm_end;
120 }
121}
122
123
124unsigned long
125arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
126 const unsigned long len, const unsigned long pgoff,
127 const unsigned long flags)
128{
129 struct vm_area_struct *vma;
130 struct mm_struct *mm = current->mm;
131 unsigned long addr = addr0;
132
133 /* requested length too big for entire address space */
134 if (len > TASK_SIZE)
135 return -ENOMEM;
136
137 if (flags & MAP_FIXED)
138 return addr;
139
140 /* for MAP_32BIT mappings we force the legact mmap base */
141 if (!test_thread_flag(TIF_IA32) && (flags & MAP_32BIT))
142 goto bottomup;
143
144 /* requesting a specific address */
145 if (addr) {
146 addr = PAGE_ALIGN(addr);
147 vma = find_vma(mm, addr);
148 if (TASK_SIZE - len >= addr &&
149 (!vma || addr + len <= vma->vm_start))
150 return addr;
151 }
152
153 /* check if free_area_cache is useful for us */
154 if (len <= mm->cached_hole_size) {
155 mm->cached_hole_size = 0;
156 mm->free_area_cache = mm->mmap_base;
157 }
158
159 /* either no address requested or can't fit in requested address hole */
160 addr = mm->free_area_cache;
161
162 /* make sure it can fit in the remaining address space */
163 if (addr > len) {
164 vma = find_vma(mm, addr-len);
165 if (!vma || addr <= vma->vm_start)
166 /* remember the address as a hint for next time */
167 return mm->free_area_cache = addr-len;
168 }
169
170 if (mm->mmap_base < len)
171 goto bottomup;
172
173 addr = mm->mmap_base-len;
174
175 do {
176 /*
177 * Lookup failure means no vma is above this address,
178 * else if new region fits below vma->vm_start,
179 * return with success:
180 */
181 vma = find_vma(mm, addr);
182 if (!vma || addr+len <= vma->vm_start)
183 /* remember the address as a hint for next time */
184 return mm->free_area_cache = addr;
185
186 /* remember the largest hole we saw so far */
187 if (addr + mm->cached_hole_size < vma->vm_start)
188 mm->cached_hole_size = vma->vm_start - addr;
189
190 /* try just below the current vma->vm_start */
191 addr = vma->vm_start-len;
192 } while (len < vma->vm_start);
193
194bottomup:
195 /*
196 * A failed mmap() very likely causes application failure,
197 * so fall back to the bottom-up function here. This scenario
198 * can happen with large stack limits and large mmap()
199 * allocations.
200 */
201 mm->cached_hole_size = ~0UL;
202 mm->free_area_cache = TASK_UNMAPPED_BASE;
203 addr = arch_get_unmapped_area(filp, addr0, len, pgoff, flags);
204 /*
205 * Restore the topdown base:
206 */
207 mm->free_area_cache = mm->mmap_base;
208 mm->cached_hole_size = ~0UL;
209
210 return addr;
211}