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1da177e4 LT |
1 | /* elf-fdpic.c: ELF FDPIC memory layout management |
2 | * | |
3 | * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved. | |
4 | * Written by David Howells (dhowells@redhat.com) | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU General Public License | |
8 | * as published by the Free Software Foundation; either version | |
9 | * 2 of the License, or (at your option) any later version. | |
10 | */ | |
11 | ||
12 | #include <linux/sched.h> | |
13 | #include <linux/mm.h> | |
14 | #include <linux/fs.h> | |
15 | #include <linux/elf-fdpic.h> | |
16 | ||
17 | /*****************************************************************************/ | |
18 | /* | |
19 | * lay out the userspace VM according to our grand design | |
20 | */ | |
21 | #ifdef CONFIG_MMU | |
22 | void elf_fdpic_arch_lay_out_mm(struct elf_fdpic_params *exec_params, | |
23 | struct elf_fdpic_params *interp_params, | |
24 | unsigned long *start_stack, | |
25 | unsigned long *start_brk) | |
26 | { | |
27 | *start_stack = 0x02200000UL; | |
28 | ||
29 | /* if the only executable is a shared object, assume that it is an interpreter rather than | |
30 | * a true executable, and map it such that "ld.so --list" comes out right | |
31 | */ | |
32 | if (!(interp_params->flags & ELF_FDPIC_FLAG_PRESENT) && | |
33 | exec_params->hdr.e_type != ET_EXEC | |
34 | ) { | |
35 | exec_params->load_addr = PAGE_SIZE; | |
36 | ||
37 | *start_brk = 0x80000000UL; | |
38 | } | |
39 | else { | |
40 | exec_params->load_addr = 0x02200000UL; | |
41 | ||
42 | if ((exec_params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) == | |
43 | ELF_FDPIC_FLAG_INDEPENDENT | |
44 | ) { | |
45 | exec_params->flags &= ~ELF_FDPIC_FLAG_ARRANGEMENT; | |
46 | exec_params->flags |= ELF_FDPIC_FLAG_CONSTDISP; | |
47 | } | |
48 | } | |
49 | ||
50 | } /* end elf_fdpic_arch_lay_out_mm() */ | |
51 | #endif | |
52 | ||
53 | /*****************************************************************************/ | |
54 | /* | |
55 | * place non-fixed mmaps firstly in the bottom part of memory, working up, and then in the top part | |
56 | * of memory, working down | |
57 | */ | |
58 | unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr, unsigned long len, | |
59 | unsigned long pgoff, unsigned long flags) | |
60 | { | |
61 | struct vm_area_struct *vma; | |
62 | unsigned long limit; | |
63 | ||
64 | if (len > TASK_SIZE) | |
65 | return -ENOMEM; | |
66 | ||
67 | /* only honour a hint if we're not going to clobber something doing so */ | |
68 | if (addr) { | |
69 | addr = PAGE_ALIGN(addr); | |
70 | vma = find_vma(current->mm, addr); | |
71 | if (TASK_SIZE - len >= addr && | |
72 | (!vma || addr + len <= vma->vm_start)) | |
73 | goto success; | |
74 | } | |
75 | ||
76 | /* search between the bottom of user VM and the stack grow area */ | |
77 | addr = PAGE_SIZE; | |
78 | limit = (current->mm->start_stack - 0x00200000); | |
79 | if (addr + len <= limit) { | |
80 | limit -= len; | |
81 | ||
82 | if (addr <= limit) { | |
83 | vma = find_vma(current->mm, PAGE_SIZE); | |
84 | for (; vma; vma = vma->vm_next) { | |
85 | if (addr > limit) | |
86 | break; | |
87 | if (addr + len <= vma->vm_start) | |
88 | goto success; | |
89 | addr = vma->vm_end; | |
90 | } | |
91 | } | |
92 | } | |
93 | ||
94 | /* search from just above the WorkRAM area to the top of memory */ | |
95 | addr = PAGE_ALIGN(0x80000000); | |
96 | limit = TASK_SIZE - len; | |
97 | if (addr <= limit) { | |
98 | vma = find_vma(current->mm, addr); | |
99 | for (; vma; vma = vma->vm_next) { | |
100 | if (addr > limit) | |
101 | break; | |
102 | if (addr + len <= vma->vm_start) | |
103 | goto success; | |
104 | addr = vma->vm_end; | |
105 | } | |
106 | ||
107 | if (!vma && addr <= limit) | |
108 | goto success; | |
109 | } | |
110 | ||
111 | #if 0 | |
112 | printk("[area] l=%lx (ENOMEM) f='%s'\n", | |
113 | len, filp ? filp->f_dentry->d_name.name : ""); | |
114 | #endif | |
115 | return -ENOMEM; | |
116 | ||
117 | success: | |
118 | #if 0 | |
119 | printk("[area] l=%lx ad=%lx f='%s'\n", | |
120 | len, addr, filp ? filp->f_dentry->d_name.name : ""); | |
121 | #endif | |
122 | return addr; | |
123 | } /* end arch_get_unmapped_area() */ |