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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#include <linux/elf.h>
18
19#include <asm/ia32.h>
20#include <asm/syscalls.h>
21
22/*
23 * Align a virtual address to avoid aliasing in the I$ on AMD F15h.
24 *
25 * @flags denotes the allocation direction - bottomup or topdown -
26 * or vDSO; see call sites below.
27 */
28unsigned long align_addr(unsigned long addr, struct file *filp,
29 enum align_flags flags)
30{
31 unsigned long tmp_addr;
32
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 addr;
36
37 if (!(current->flags & PF_RANDOMIZE))
38 return addr;
39
40 if (!((flags & ALIGN_VDSO) || filp))
41 return addr;
42
43 tmp_addr = addr;
44
45 /*
46 * We need an address which is <= than the original
47 * one only when in topdown direction.
48 */
49 if (!(flags & ALIGN_TOPDOWN))
50 tmp_addr += va_align.mask;
51
52 tmp_addr &= ~va_align.mask;
53
54 return tmp_addr;
55}
56
57static int __init control_va_addr_alignment(char *str)
58{
59 /* guard against enabling this on other CPU families */
60 if (va_align.flags < 0)
61 return 1;
62
63 if (*str == 0)
64 return 1;
65
66 if (*str == '=')
67 str++;
68
69 if (!strcmp(str, "32"))
70 va_align.flags = ALIGN_VA_32;
71 else if (!strcmp(str, "64"))
72 va_align.flags = ALIGN_VA_64;
73 else if (!strcmp(str, "off"))
74 va_align.flags = 0;
75 else if (!strcmp(str, "on"))
76 va_align.flags = ALIGN_VA_32 | ALIGN_VA_64;
77 else
78 return 0;
79
80 return 1;
81}
82__setup("align_va_addr", control_va_addr_alignment);
83
84SYSCALL_DEFINE6(mmap, unsigned long, addr, unsigned long, len,
85 unsigned long, prot, unsigned long, flags,
86 unsigned long, fd, unsigned long, off)
87{
88 long error;
89 error = -EINVAL;
90 if (off & ~PAGE_MASK)
91 goto out;
92
93 error = sys_mmap_pgoff(addr, len, prot, flags, fd, off >> PAGE_SHIFT);
94out:
95 return error;
96}
97
98static void find_start_end(unsigned long flags, unsigned long *begin,
99 unsigned long *end)
100{
101 if (!test_thread_flag(TIF_ADDR32) && (flags & MAP_32BIT)) {
102 unsigned long new_begin;
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
109 of playground for now. -AK */
110 *begin = 0x40000000;
111 *end = 0x80000000;
112 if (current->flags & PF_RANDOMIZE) {
113 new_begin = randomize_range(*begin, *begin + 0x02000000, 0);
114 if (new_begin)
115 *begin = new_begin;
116 }
117 } else {
118 *begin = TASK_UNMAPPED_BASE;
119 *end = TASK_SIZE;
120 }
121}
122
123unsigned long
124arch_get_unmapped_area(struct file *filp, unsigned long addr,
125 unsigned long len, unsigned long pgoff, unsigned long flags)
126{
127 struct mm_struct *mm = current->mm;
128 struct vm_area_struct *vma;
129 unsigned long start_addr;
130 unsigned long begin, end;
131
132 if (flags & MAP_FIXED)
133 return addr;
134
135 find_start_end(flags, &begin, &end);
136
137 if (len > end)
138 return -ENOMEM;
139
140 if (addr) {
141 addr = PAGE_ALIGN(addr);
142 vma = find_vma(mm, addr);
143 if (end - len >= addr &&
144 (!vma || addr + len <= vma->vm_start))
145 return addr;
146 }
147 if (((flags & MAP_32BIT) || test_thread_flag(TIF_ADDR32))
148 && len <= mm->cached_hole_size) {
149 mm->cached_hole_size = 0;
150 mm->free_area_cache = begin;
151 }
152 addr = mm->free_area_cache;
153 if (addr < begin)
154 addr = begin;
155 start_addr = addr;
156
157full_search:
158
159 addr = align_addr(addr, filp, 0);
160
161 for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
162 /* At this point: (!vma || addr < vma->vm_end). */
163 if (end - len < addr) {
164 /*
165 * Start a new search - just in case we missed
166 * some holes.
167 */
168 if (start_addr != begin) {
169 start_addr = addr = begin;
170 mm->cached_hole_size = 0;
171 goto full_search;
172 }
173 return -ENOMEM;
174 }
175 if (!vma || addr + len <= vma->vm_start) {
176 /*
177 * Remember the place where we stopped the search:
178 */
179 mm->free_area_cache = addr + len;
180 return addr;
181 }
182 if (addr + mm->cached_hole_size < vma->vm_start)
183 mm->cached_hole_size = vma->vm_start - addr;
184
185 addr = vma->vm_end;
186 addr = align_addr(addr, filp, 0);
187 }
188}
189
190
191unsigned long
192arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
193 const unsigned long len, const unsigned long pgoff,
194 const unsigned long flags)
195{
196 struct vm_area_struct *vma;
197 struct mm_struct *mm = current->mm;
198 unsigned long addr = addr0, start_addr;
199
200 /* requested length too big for entire address space */
201 if (len > TASK_SIZE)
202 return -ENOMEM;
203
204 if (flags & MAP_FIXED)
205 return addr;
206
207 /* for MAP_32BIT mappings we force the legact mmap base */
208 if (!test_thread_flag(TIF_ADDR32) && (flags & MAP_32BIT))
209 goto bottomup;
210
211 /* requesting a specific address */
212 if (addr) {
213 addr = PAGE_ALIGN(addr);
214 vma = find_vma(mm, addr);
215 if (TASK_SIZE - len >= addr &&
216 (!vma || addr + len <= vma->vm_start))
217 return addr;
218 }
219
220 /* check if free_area_cache is useful for us */
221 if (len <= mm->cached_hole_size) {
222 mm->cached_hole_size = 0;
223 mm->free_area_cache = mm->mmap_base;
224 }
225
226try_again:
227 /* either no address requested or can't fit in requested address hole */
228 start_addr = addr = mm->free_area_cache;
229
230 if (addr < len)
231 goto fail;
232
233 addr -= len;
234 do {
235 addr = align_addr(addr, filp, ALIGN_TOPDOWN);
236
237 /*
238 * Lookup failure means no vma is above this address,
239 * else if new region fits below vma->vm_start,
240 * return with success:
241 */
242 vma = find_vma(mm, addr);
243 if (!vma || addr+len <= vma->vm_start)
244 /* remember the address as a hint for next time */
245 return mm->free_area_cache = addr;
246
247 /* remember the largest hole we saw so far */
248 if (addr + mm->cached_hole_size < vma->vm_start)
249 mm->cached_hole_size = vma->vm_start - addr;
250
251 /* try just below the current vma->vm_start */
252 addr = vma->vm_start-len;
253 } while (len < vma->vm_start);
254
255fail:
256 /*
257 * if hint left us with no space for the requested
258 * mapping then try again:
259 */
260 if (start_addr != mm->mmap_base) {
261 mm->free_area_cache = mm->mmap_base;
262 mm->cached_hole_size = 0;
263 goto try_again;
264 }
265
266bottomup:
267 /*
268 * A failed mmap() very likely causes application failure,
269 * so fall back to the bottom-up function here. This scenario
270 * can happen with large stack limits and large mmap()
271 * allocations.
272 */
273 mm->cached_hole_size = ~0UL;
274 mm->free_area_cache = TASK_UNMAPPED_BASE;
275 addr = arch_get_unmapped_area(filp, addr0, len, pgoff, flags);
276 /*
277 * Restore the topdown base:
278 */
279 mm->free_area_cache = mm->mmap_base;
280 mm->cached_hole_size = ~0UL;
281
282 return addr;
283}
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
22#include <asm/elf.h>
23#include <asm/ia32.h>
24
25/*
26 * Align a virtual address to avoid aliasing in the I$ on AMD F15h.
27 */
28static unsigned long get_align_mask(void)
29{
30 /* handle 32- and 64-bit case with a single conditional */
31 if (va_align.flags < 0 || !(va_align.flags & (2 - mmap_is_ia32())))
32 return 0;
33
34 if (!(current->flags & PF_RANDOMIZE))
35 return 0;
36
37 return va_align.mask;
38}
39
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 */
50static unsigned long get_align_bits(void)
51{
52 return va_align.bits & get_align_mask();
53}
54
55unsigned long align_vdso_addr(unsigned long addr)
56{
57 unsigned long align_mask = get_align_mask();
58 addr = (addr + align_mask) & ~align_mask;
59 return addr | get_align_bits();
60}
61
62static 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
89SYSCALL_DEFINE6(mmap, unsigned long, addr, unsigned long, len,
90 unsigned long, prot, unsigned long, flags,
91 unsigned long, fd, unsigned long, off)
92{
93 if (off & ~PAGE_MASK)
94 return -EINVAL;
95
96 return ksys_mmap_pgoff(addr, len, prot, flags, fd, off >> PAGE_SHIFT);
97}
98
99static void find_start_end(unsigned long addr, unsigned long flags,
100 unsigned long *begin, unsigned long *end)
101{
102 if (!in_32bit_syscall() && (flags & MAP_32BIT)) {
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
109 of playground for now. -AK */
110 *begin = 0x40000000;
111 *end = 0x80000000;
112 if (current->flags & PF_RANDOMIZE) {
113 *begin = randomize_page(*begin, 0x02000000);
114 }
115 return;
116 }
117
118 *begin = get_mmap_base(1);
119 if (in_32bit_syscall())
120 *end = task_size_32bit();
121 else
122 *end = task_size_64bit(addr > DEFAULT_MAP_WINDOW);
123}
124
125unsigned long
126arch_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;
131 struct vm_unmapped_area_info info;
132 unsigned long begin, end;
133
134 if (flags & MAP_FIXED)
135 return addr;
136
137 find_start_end(addr, flags, &begin, &end);
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 &&
146 (!vma || addr + len <= vm_start_gap(vma)))
147 return addr;
148 }
149
150 info.flags = 0;
151 info.length = len;
152 info.low_limit = begin;
153 info.high_limit = end;
154 info.align_mask = 0;
155 info.align_offset = pgoff << PAGE_SHIFT;
156 if (filp) {
157 info.align_mask = get_align_mask();
158 info.align_offset += get_align_bits();
159 }
160 return vm_unmapped_area(&info);
161}
162
163unsigned long
164arch_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;
170 unsigned long addr = addr0;
171 struct vm_unmapped_area_info info;
172
173 /* requested length too big for entire address space */
174 if (len > TASK_SIZE)
175 return -ENOMEM;
176
177 /* No address checking. See comment at mmap_address_hint_valid() */
178 if (flags & MAP_FIXED)
179 return addr;
180
181 /* for MAP_32BIT mappings we force the legacy mmap base */
182 if (!in_32bit_syscall() && (flags & MAP_32BIT))
183 goto bottomup;
184
185 /* requesting a specific address */
186 if (addr) {
187 addr &= PAGE_MASK;
188 if (!mmap_address_hint_valid(addr, len))
189 goto get_unmapped_area;
190
191 vma = find_vma(mm, addr);
192 if (!vma || addr + len <= vm_start_gap(vma))
193 return addr;
194 }
195get_unmapped_area:
196
197 info.flags = VM_UNMAPPED_AREA_TOPDOWN;
198 info.length = len;
199 info.low_limit = PAGE_SIZE;
200 info.high_limit = get_mmap_base(0);
201
202 /*
203 * If hint address is above DEFAULT_MAP_WINDOW, look for unmapped area
204 * in the full address space.
205 *
206 * !in_32bit_syscall() check to avoid high addresses for x32
207 * (and make it no op on native i386).
208 */
209 if (addr > DEFAULT_MAP_WINDOW && !in_32bit_syscall())
210 info.high_limit += TASK_SIZE_MAX - DEFAULT_MAP_WINDOW;
211
212 info.align_mask = 0;
213 info.align_offset = pgoff << PAGE_SHIFT;
214 if (filp) {
215 info.align_mask = get_align_mask();
216 info.align_offset += get_align_bits();
217 }
218 addr = vm_unmapped_area(&info);
219 if (!(addr & ~PAGE_MASK))
220 return addr;
221 VM_BUG_ON(addr != -ENOMEM);
222
223bottomup:
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 */
230 return arch_get_unmapped_area(filp, addr0, len, pgoff, flags);
231}