Loading...
1/*
2 * This file is subject to the terms and conditions of the GNU General Public
3 * License. See the file "COPYING" in the main directory of this archive
4 * for more details.
5 *
6 * Copyright (C) 2011 Wind River Systems,
7 * written by Ralf Baechle <ralf@linux-mips.org>
8 */
9#include <linux/compiler.h>
10#include <linux/errno.h>
11#include <linux/mm.h>
12#include <linux/mman.h>
13#include <linux/module.h>
14#include <linux/personality.h>
15#include <linux/random.h>
16#include <linux/sched.h>
17
18unsigned long shm_align_mask = PAGE_SIZE - 1; /* Sane caches */
19EXPORT_SYMBOL(shm_align_mask);
20
21/* gap between mmap and stack */
22#define MIN_GAP (128*1024*1024UL)
23#define MAX_GAP ((TASK_SIZE)/6*5)
24
25static int mmap_is_legacy(void)
26{
27 if (current->personality & ADDR_COMPAT_LAYOUT)
28 return 1;
29
30 if (rlimit(RLIMIT_STACK) == RLIM_INFINITY)
31 return 1;
32
33 return sysctl_legacy_va_layout;
34}
35
36static unsigned long mmap_base(unsigned long rnd)
37{
38 unsigned long gap = rlimit(RLIMIT_STACK);
39
40 if (gap < MIN_GAP)
41 gap = MIN_GAP;
42 else if (gap > MAX_GAP)
43 gap = MAX_GAP;
44
45 return PAGE_ALIGN(TASK_SIZE - gap - rnd);
46}
47
48#define COLOUR_ALIGN(addr, pgoff) \
49 ((((addr) + shm_align_mask) & ~shm_align_mask) + \
50 (((pgoff) << PAGE_SHIFT) & shm_align_mask))
51
52enum mmap_allocation_direction {UP, DOWN};
53
54static unsigned long arch_get_unmapped_area_common(struct file *filp,
55 unsigned long addr0, unsigned long len, unsigned long pgoff,
56 unsigned long flags, enum mmap_allocation_direction dir)
57{
58 struct mm_struct *mm = current->mm;
59 struct vm_area_struct *vma;
60 unsigned long addr = addr0;
61 int do_color_align;
62 struct vm_unmapped_area_info info;
63
64 if (unlikely(len > TASK_SIZE))
65 return -ENOMEM;
66
67 if (flags & MAP_FIXED) {
68 /* Even MAP_FIXED mappings must reside within TASK_SIZE */
69 if (TASK_SIZE - len < addr)
70 return -EINVAL;
71
72 /*
73 * We do not accept a shared mapping if it would violate
74 * cache aliasing constraints.
75 */
76 if ((flags & MAP_SHARED) &&
77 ((addr - (pgoff << PAGE_SHIFT)) & shm_align_mask))
78 return -EINVAL;
79 return addr;
80 }
81
82 do_color_align = 0;
83 if (filp || (flags & MAP_SHARED))
84 do_color_align = 1;
85
86 /* requesting a specific address */
87 if (addr) {
88 if (do_color_align)
89 addr = COLOUR_ALIGN(addr, pgoff);
90 else
91 addr = PAGE_ALIGN(addr);
92
93 vma = find_vma(mm, addr);
94 if (TASK_SIZE - len >= addr &&
95 (!vma || addr + len <= vma->vm_start))
96 return addr;
97 }
98
99 info.length = len;
100 info.align_mask = do_color_align ? (PAGE_MASK & shm_align_mask) : 0;
101 info.align_offset = pgoff << PAGE_SHIFT;
102
103 if (dir == DOWN) {
104 info.flags = VM_UNMAPPED_AREA_TOPDOWN;
105 info.low_limit = PAGE_SIZE;
106 info.high_limit = mm->mmap_base;
107 addr = vm_unmapped_area(&info);
108
109 if (!(addr & ~PAGE_MASK))
110 return addr;
111
112 /*
113 * A failed mmap() very likely causes application failure,
114 * so fall back to the bottom-up function here. This scenario
115 * can happen with large stack limits and large mmap()
116 * allocations.
117 */
118 }
119
120 info.flags = 0;
121 info.low_limit = mm->mmap_base;
122 info.high_limit = TASK_SIZE;
123 return vm_unmapped_area(&info);
124}
125
126unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr0,
127 unsigned long len, unsigned long pgoff, unsigned long flags)
128{
129 return arch_get_unmapped_area_common(filp,
130 addr0, len, pgoff, flags, UP);
131}
132
133/*
134 * There is no need to export this but sched.h declares the function as
135 * extern so making it static here results in an error.
136 */
137unsigned long arch_get_unmapped_area_topdown(struct file *filp,
138 unsigned long addr0, unsigned long len, unsigned long pgoff,
139 unsigned long flags)
140{
141 return arch_get_unmapped_area_common(filp,
142 addr0, len, pgoff, flags, DOWN);
143}
144
145unsigned long arch_mmap_rnd(void)
146{
147 unsigned long rnd;
148
149 rnd = get_random_long();
150 rnd <<= PAGE_SHIFT;
151 if (TASK_IS_32BIT_ADDR)
152 rnd &= 0xfffffful;
153 else
154 rnd &= 0xffffffful;
155
156 return rnd;
157}
158
159void arch_pick_mmap_layout(struct mm_struct *mm)
160{
161 unsigned long random_factor = 0UL;
162
163 if (current->flags & PF_RANDOMIZE)
164 random_factor = arch_mmap_rnd();
165
166 if (mmap_is_legacy()) {
167 mm->mmap_base = TASK_UNMAPPED_BASE + random_factor;
168 mm->get_unmapped_area = arch_get_unmapped_area;
169 } else {
170 mm->mmap_base = mmap_base(random_factor);
171 mm->get_unmapped_area = arch_get_unmapped_area_topdown;
172 }
173}
174
175static inline unsigned long brk_rnd(void)
176{
177 unsigned long rnd = get_random_long();
178
179 rnd = rnd << PAGE_SHIFT;
180 /* 8MB for 32bit, 256MB for 64bit */
181 if (TASK_IS_32BIT_ADDR)
182 rnd = rnd & 0x7ffffful;
183 else
184 rnd = rnd & 0xffffffful;
185
186 return rnd;
187}
188
189unsigned long arch_randomize_brk(struct mm_struct *mm)
190{
191 unsigned long base = mm->brk;
192 unsigned long ret;
193
194 ret = PAGE_ALIGN(base + brk_rnd());
195
196 if (ret < mm->brk)
197 return mm->brk;
198
199 return ret;
200}
201
202int __virt_addr_valid(const volatile void *kaddr)
203{
204 return pfn_valid(PFN_DOWN(virt_to_phys(kaddr)));
205}
206EXPORT_SYMBOL_GPL(__virt_addr_valid);
1/*
2 * This file is subject to the terms and conditions of the GNU General Public
3 * License. See the file "COPYING" in the main directory of this archive
4 * for more details.
5 *
6 * Copyright (C) 2011 Wind River Systems,
7 * written by Ralf Baechle <ralf@linux-mips.org>
8 */
9#include <linux/compiler.h>
10#include <linux/elf-randomize.h>
11#include <linux/errno.h>
12#include <linux/mm.h>
13#include <linux/mman.h>
14#include <linux/export.h>
15#include <linux/personality.h>
16#include <linux/random.h>
17#include <linux/sched/signal.h>
18#include <linux/sched/mm.h>
19
20unsigned long shm_align_mask = PAGE_SIZE - 1; /* Sane caches */
21EXPORT_SYMBOL(shm_align_mask);
22
23#define COLOUR_ALIGN(addr, pgoff) \
24 ((((addr) + shm_align_mask) & ~shm_align_mask) + \
25 (((pgoff) << PAGE_SHIFT) & shm_align_mask))
26
27enum mmap_allocation_direction {UP, DOWN};
28
29static unsigned long arch_get_unmapped_area_common(struct file *filp,
30 unsigned long addr0, unsigned long len, unsigned long pgoff,
31 unsigned long flags, enum mmap_allocation_direction dir)
32{
33 struct mm_struct *mm = current->mm;
34 struct vm_area_struct *vma;
35 unsigned long addr = addr0;
36 int do_color_align;
37 struct vm_unmapped_area_info info;
38
39 if (unlikely(len > TASK_SIZE))
40 return -ENOMEM;
41
42 if (flags & MAP_FIXED) {
43 /* Even MAP_FIXED mappings must reside within TASK_SIZE */
44 if (TASK_SIZE - len < addr)
45 return -EINVAL;
46
47 /*
48 * We do not accept a shared mapping if it would violate
49 * cache aliasing constraints.
50 */
51 if ((flags & MAP_SHARED) &&
52 ((addr - (pgoff << PAGE_SHIFT)) & shm_align_mask))
53 return -EINVAL;
54 return addr;
55 }
56
57 do_color_align = 0;
58 if (filp || (flags & MAP_SHARED))
59 do_color_align = 1;
60
61 /* requesting a specific address */
62 if (addr) {
63 if (do_color_align)
64 addr = COLOUR_ALIGN(addr, pgoff);
65 else
66 addr = PAGE_ALIGN(addr);
67
68 vma = find_vma(mm, addr);
69 if (TASK_SIZE - len >= addr &&
70 (!vma || addr + len <= vm_start_gap(vma)))
71 return addr;
72 }
73
74 info.length = len;
75 info.align_mask = do_color_align ? (PAGE_MASK & shm_align_mask) : 0;
76 info.align_offset = pgoff << PAGE_SHIFT;
77
78 if (dir == DOWN) {
79 info.flags = VM_UNMAPPED_AREA_TOPDOWN;
80 info.low_limit = PAGE_SIZE;
81 info.high_limit = mm->mmap_base;
82 addr = vm_unmapped_area(&info);
83
84 if (!(addr & ~PAGE_MASK))
85 return addr;
86
87 /*
88 * A failed mmap() very likely causes application failure,
89 * so fall back to the bottom-up function here. This scenario
90 * can happen with large stack limits and large mmap()
91 * allocations.
92 */
93 }
94
95 info.flags = 0;
96 info.low_limit = mm->mmap_base;
97 info.high_limit = TASK_SIZE;
98 return vm_unmapped_area(&info);
99}
100
101unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr0,
102 unsigned long len, unsigned long pgoff, unsigned long flags)
103{
104 return arch_get_unmapped_area_common(filp,
105 addr0, len, pgoff, flags, UP);
106}
107
108/*
109 * There is no need to export this but sched.h declares the function as
110 * extern so making it static here results in an error.
111 */
112unsigned long arch_get_unmapped_area_topdown(struct file *filp,
113 unsigned long addr0, unsigned long len, unsigned long pgoff,
114 unsigned long flags)
115{
116 return arch_get_unmapped_area_common(filp,
117 addr0, len, pgoff, flags, DOWN);
118}
119
120bool __virt_addr_valid(const volatile void *kaddr)
121{
122 unsigned long vaddr = (unsigned long)kaddr;
123
124 if ((vaddr < PAGE_OFFSET) || (vaddr >= MAP_BASE))
125 return false;
126
127 return pfn_valid(PFN_DOWN(virt_to_phys(kaddr)));
128}
129EXPORT_SYMBOL_GPL(__virt_addr_valid);