summaryrefslogtreecommitdiffstats
path: root/arch/x86/kernel/sys_x86_64.c
blob: 8aa2057efd12618aa20874b8a71fc40527cc6819 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/syscalls.h>
#include <linux/mm.h>
#include <linux/fs.h>
#include <linux/smp.h>
#include <linux/sem.h>
#include <linux/msg.h>
#include <linux/shm.h>
#include <linux/stat.h>
#include <linux/mman.h>
#include <linux/file.h>
#include <linux/utsname.h>
#include <linux/personality.h>
#include <linux/random.h>
#include <linux/uaccess.h>

#include <asm/ia32.h>
#include <asm/syscalls.h>

SYSCALL_DEFINE6(mmap, unsigned long, addr, unsigned long, len,
		unsigned long, prot, unsigned long, flags,
		unsigned long, fd, unsigned long, off)
{
	long error;
	error = -EINVAL;
	if (off & ~PAGE_MASK)
		goto out;

	error = sys_mmap_pgoff(addr, len, prot, flags, fd, off >> PAGE_SHIFT);
out:
	return error;
}

static void find_start_end(unsigned long flags, unsigned long *begin,
			   unsigned long *end)
{
	if (!test_thread_flag(TIF_IA32) && (flags & MAP_32BIT)) {
		unsigned long new_begin;
		/* This is usually used needed to map code in small
		   model, so it needs to be in the first 31bit. Limit
		   it to that.  This means we need to move the
		   unmapped base down for this case. This can give
		   conflicts with the heap, but we assume that glibc
		   malloc knows how to fall back to mmap. Give it 1GB
		   of playground for now. -AK */
		*begin = 0x40000000;
		*end = 0x80000000;
		if (current->flags & PF_RANDOMIZE) {
			new_begin = randomize_range(*begin, *begin + 0x02000000, 0);
			if (new_begin)
				*begin = new_begin;
		}
	} else {
		*begin = TASK_UNMAPPED_BASE;
		*end = TASK_SIZE;
	}
}

unsigned long
arch_get_unmapped_area(struct file *filp, unsigned long addr,
		unsigned long len, unsigned long pgoff, unsigned long flags)
{
	struct mm_struct *mm = current->mm;
	struct vm_area_struct *vma;
	unsigned long start_addr;
	unsigned long begin, end;

	if (flags & MAP_FIXED)
		return addr;

	find_start_end(flags, &begin, &end);

	if (len > end)
		return -ENOMEM;

	if (addr) {
		addr = PAGE_ALIGN(addr);
		vma = find_vma(mm, addr);
		if (end - len >= addr &&
		    (!vma || addr + len <= vma->vm_start))
			return addr;
	}
	if (((flags & MAP_32BIT) || test_thread_flag(TIF_IA32))
	    && len <= mm->cached_hole_size) {
		mm->cached_hole_size = 0;
		mm->free_area_cache = begin;
	}
	addr = mm->free_area_cache;
	if (addr < begin)
		addr = begin;
	start_addr = addr;

full_search:
	for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
		/* At this point:  (!vma || addr < vma->vm_end). */
		if (end - len < addr) {
			/*
			 * Start a new search - just in case we missed
			 * some holes.
			 */
			if (start_addr != begin) {
				start_addr = addr = begin;
				mm->cached_hole_size = 0;
				goto full_search;
			}
			return -ENOMEM;
		}
		if (!vma || addr + len <= vma->vm_start) {
			/*
			 * Remember the place where we stopped the search:
			 */
			mm->free_area_cache = addr + len;
			return addr;
		}
		if (addr + mm->cached_hole_size < vma->vm_start)
			mm->cached_hole_size = vma->vm_start - addr;

		addr = vma->vm_end;
	}
}


unsigned long
arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
			  const unsigned long len, const unsigned long pgoff,
			  const unsigned long flags)
{
	struct vm_area_struct *vma;
	struct mm_struct *mm = current->mm;
	unsigned long addr = addr0;

	/* requested length too big for entire address space */
	if (len > TASK_SIZE)
		return -ENOMEM;

	if (flags & MAP_FIXED)
		return addr;

	/* for MAP_32BIT mappings we force the legact mmap base */
	if (!test_thread_flag(TIF_IA32) && (flags & MAP_32BIT))
		goto bottomup;

	/* requesting a specific address */
	if (addr) {
		addr = PAGE_ALIGN(addr);
		vma = find_vma(mm, addr);
		if (TASK_SIZE - len >= addr &&
				(!vma || addr + len <= vma->vm_start))
			return addr;
	}

	/* check if free_area_cache is useful for us */
	if (len <= mm->cached_hole_size) {
		mm->cached_hole_size = 0;
		mm->free_area_cache = mm->mmap_base;
	}

	/* either no address requested or can't fit in requested address hole */
	addr = mm->free_area_cache;

	/* make sure it can fit in the remaining address space */
	if (addr > len) {
		vma = find_vma(mm, addr-len);
		if (!vma || addr <= vma->vm_start)
			/* remember the address as a hint for next time */
			return mm->free_area_cache = addr-len;
	}

	if (mm->mmap_base < len)
		goto bottomup;

	addr = mm->mmap_base-len;

	do {
		/*
		 * Lookup failure means no vma is above this address,
		 * else if new region fits below vma->vm_start,
		 * return with success:
		 */
		vma = find_vma(mm, addr);
		if (!vma || addr+len <= vma->vm_start)
			/* remember the address as a hint for next time */
			return mm->free_area_cache = addr;

		/* remember the largest hole we saw so far */
		if (addr + mm->cached_hole_size < vma->vm_start)
			mm->cached_hole_size = vma->vm_start - addr;

		/* try just below the current vma->vm_start */
		addr = vma->vm_start-len;
	} while (len < vma->vm_start);

bottomup:
	/*
	 * A failed mmap() very likely causes application failure,
	 * so fall back to the bottom-up function here. This scenario
	 * can happen with large stack limits and large mmap()
	 * allocations.
	 */
	mm->cached_hole_size = ~0UL;
	mm->free_area_cache = TASK_UNMAPPED_BASE;
	addr = arch_get_unmapped_area(filp, addr0, len, pgoff, flags);
	/*
	 * Restore the topdown base:
	 */
	mm->free_area_cache = mm->mmap_base;
	mm->cached_hole_size = ~0UL;

	return addr;
}


SYSCALL_DEFINE1(uname, struct new_utsname __user *, name)
{
	int err;
	down_read(&uts_sem);
	err = copy_to_user(name, utsname(), sizeof(*name));
	up_read(&uts_sem);
	if (personality(current->personality) == PER_LINUX32)
		err |= copy_to_user(&name->machine, "i686", 5);
	return err ? -EFAULT : 0;
}