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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);
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/* gap between mmap and stack */
24#define MIN_GAP (128*1024*1024UL)
25#define MAX_GAP ((TASK_SIZE)/6*5)
26
27static int mmap_is_legacy(struct rlimit *rlim_stack)
28{
29 if (current->personality & ADDR_COMPAT_LAYOUT)
30 return 1;
31
32 if (rlim_stack->rlim_cur == RLIM_INFINITY)
33 return 1;
34
35 return sysctl_legacy_va_layout;
36}
37
38static unsigned long mmap_base(unsigned long rnd, struct rlimit *rlim_stack)
39{
40 unsigned long gap = rlim_stack->rlim_cur;
41
42 if (gap < MIN_GAP)
43 gap = MIN_GAP;
44 else if (gap > MAX_GAP)
45 gap = MAX_GAP;
46
47 return PAGE_ALIGN(TASK_SIZE - gap - rnd);
48}
49
50#define COLOUR_ALIGN(addr, pgoff) \
51 ((((addr) + shm_align_mask) & ~shm_align_mask) + \
52 (((pgoff) << PAGE_SHIFT) & shm_align_mask))
53
54enum mmap_allocation_direction {UP, DOWN};
55
56static unsigned long arch_get_unmapped_area_common(struct file *filp,
57 unsigned long addr0, unsigned long len, unsigned long pgoff,
58 unsigned long flags, enum mmap_allocation_direction dir)
59{
60 struct mm_struct *mm = current->mm;
61 struct vm_area_struct *vma;
62 unsigned long addr = addr0;
63 int do_color_align;
64 struct vm_unmapped_area_info info;
65
66 if (unlikely(len > TASK_SIZE))
67 return -ENOMEM;
68
69 if (flags & MAP_FIXED) {
70 /* Even MAP_FIXED mappings must reside within TASK_SIZE */
71 if (TASK_SIZE - len < addr)
72 return -EINVAL;
73
74 /*
75 * We do not accept a shared mapping if it would violate
76 * cache aliasing constraints.
77 */
78 if ((flags & MAP_SHARED) &&
79 ((addr - (pgoff << PAGE_SHIFT)) & shm_align_mask))
80 return -EINVAL;
81 return addr;
82 }
83
84 do_color_align = 0;
85 if (filp || (flags & MAP_SHARED))
86 do_color_align = 1;
87
88 /* requesting a specific address */
89 if (addr) {
90 if (do_color_align)
91 addr = COLOUR_ALIGN(addr, pgoff);
92 else
93 addr = PAGE_ALIGN(addr);
94
95 vma = find_vma(mm, addr);
96 if (TASK_SIZE - len >= addr &&
97 (!vma || addr + len <= vm_start_gap(vma)))
98 return addr;
99 }
100
101 info.length = len;
102 info.align_mask = do_color_align ? (PAGE_MASK & shm_align_mask) : 0;
103 info.align_offset = pgoff << PAGE_SHIFT;
104
105 if (dir == DOWN) {
106 info.flags = VM_UNMAPPED_AREA_TOPDOWN;
107 info.low_limit = PAGE_SIZE;
108 info.high_limit = mm->mmap_base;
109 addr = vm_unmapped_area(&info);
110
111 if (!(addr & ~PAGE_MASK))
112 return addr;
113
114 /*
115 * A failed mmap() very likely causes application failure,
116 * so fall back to the bottom-up function here. This scenario
117 * can happen with large stack limits and large mmap()
118 * allocations.
119 */
120 }
121
122 info.flags = 0;
123 info.low_limit = mm->mmap_base;
124 info.high_limit = TASK_SIZE;
125 return vm_unmapped_area(&info);
126}
127
128unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr0,
129 unsigned long len, unsigned long pgoff, unsigned long flags)
130{
131 return arch_get_unmapped_area_common(filp,
132 addr0, len, pgoff, flags, UP);
133}
134
135/*
136 * There is no need to export this but sched.h declares the function as
137 * extern so making it static here results in an error.
138 */
139unsigned long arch_get_unmapped_area_topdown(struct file *filp,
140 unsigned long addr0, unsigned long len, unsigned long pgoff,
141 unsigned long flags)
142{
143 return arch_get_unmapped_area_common(filp,
144 addr0, len, pgoff, flags, DOWN);
145}
146
147unsigned long arch_mmap_rnd(void)
148{
149 unsigned long rnd;
150
151#ifdef CONFIG_COMPAT
152 if (TASK_IS_32BIT_ADDR)
153 rnd = get_random_long() & ((1UL << mmap_rnd_compat_bits) - 1);
154 else
155#endif /* CONFIG_COMPAT */
156 rnd = get_random_long() & ((1UL << mmap_rnd_bits) - 1);
157
158 return rnd << PAGE_SHIFT;
159}
160
161void arch_pick_mmap_layout(struct mm_struct *mm, struct rlimit *rlim_stack)
162{
163 unsigned long random_factor = 0UL;
164
165 if (current->flags & PF_RANDOMIZE)
166 random_factor = arch_mmap_rnd();
167
168 if (mmap_is_legacy(rlim_stack)) {
169 mm->mmap_base = TASK_UNMAPPED_BASE + random_factor;
170 mm->get_unmapped_area = arch_get_unmapped_area;
171 } else {
172 mm->mmap_base = mmap_base(random_factor, rlim_stack);
173 mm->get_unmapped_area = arch_get_unmapped_area_topdown;
174 }
175}
176
177static inline unsigned long brk_rnd(void)
178{
179 unsigned long rnd = get_random_long();
180
181 rnd = rnd << PAGE_SHIFT;
182 /* 8MB for 32bit, 256MB for 64bit */
183 if (TASK_IS_32BIT_ADDR)
184 rnd = rnd & 0x7ffffful;
185 else
186 rnd = rnd & 0xffffffful;
187
188 return rnd;
189}
190
191unsigned long arch_randomize_brk(struct mm_struct *mm)
192{
193 unsigned long base = mm->brk;
194 unsigned long ret;
195
196 ret = PAGE_ALIGN(base + brk_rnd());
197
198 if (ret < mm->brk)
199 return mm->brk;
200
201 return ret;
202}
203
204int __virt_addr_valid(const volatile void *kaddr)
205{
206 return pfn_valid(PFN_DOWN(virt_to_phys(kaddr)));
207}
208EXPORT_SYMBOL_GPL(__virt_addr_valid);