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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> | |
5616df20 | 16 | #include <asm/mman.h> |
1da177e4 LT |
17 | |
18 | /*****************************************************************************/ | |
19 | /* | |
20 | * lay out the userspace VM according to our grand design | |
21 | */ | |
22 | #ifdef CONFIG_MMU | |
23 | void elf_fdpic_arch_lay_out_mm(struct elf_fdpic_params *exec_params, | |
24 | struct elf_fdpic_params *interp_params, | |
25 | unsigned long *start_stack, | |
26 | unsigned long *start_brk) | |
27 | { | |
28 | *start_stack = 0x02200000UL; | |
29 | ||
30 | /* if the only executable is a shared object, assume that it is an interpreter rather than | |
31 | * a true executable, and map it such that "ld.so --list" comes out right | |
32 | */ | |
33 | if (!(interp_params->flags & ELF_FDPIC_FLAG_PRESENT) && | |
34 | exec_params->hdr.e_type != ET_EXEC | |
35 | ) { | |
36 | exec_params->load_addr = PAGE_SIZE; | |
37 | ||
38 | *start_brk = 0x80000000UL; | |
39 | } | |
40 | else { | |
41 | exec_params->load_addr = 0x02200000UL; | |
42 | ||
43 | if ((exec_params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) == | |
44 | ELF_FDPIC_FLAG_INDEPENDENT | |
45 | ) { | |
46 | exec_params->flags &= ~ELF_FDPIC_FLAG_ARRANGEMENT; | |
47 | exec_params->flags |= ELF_FDPIC_FLAG_CONSTDISP; | |
48 | } | |
49 | } | |
50 | ||
51 | } /* end elf_fdpic_arch_lay_out_mm() */ | |
52 | #endif | |
53 | ||
54 | /*****************************************************************************/ | |
55 | /* | |
56 | * place non-fixed mmaps firstly in the bottom part of memory, working up, and then in the top part | |
57 | * of memory, working down | |
58 | */ | |
59 | unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr, unsigned long len, | |
60 | unsigned long pgoff, unsigned long flags) | |
61 | { | |
62 | struct vm_area_struct *vma; | |
63 | unsigned long limit; | |
64 | ||
65 | if (len > TASK_SIZE) | |
66 | return -ENOMEM; | |
67 | ||
2fd3beba BH |
68 | /* handle MAP_FIXED */ |
69 | if (flags & MAP_FIXED) | |
70 | return addr; | |
71 | ||
1da177e4 LT |
72 | /* only honour a hint if we're not going to clobber something doing so */ |
73 | if (addr) { | |
74 | addr = PAGE_ALIGN(addr); | |
75 | vma = find_vma(current->mm, addr); | |
76 | if (TASK_SIZE - len >= addr && | |
77 | (!vma || addr + len <= vma->vm_start)) | |
78 | goto success; | |
79 | } | |
80 | ||
81 | /* search between the bottom of user VM and the stack grow area */ | |
82 | addr = PAGE_SIZE; | |
83 | limit = (current->mm->start_stack - 0x00200000); | |
84 | if (addr + len <= limit) { | |
85 | limit -= len; | |
86 | ||
87 | if (addr <= limit) { | |
88 | vma = find_vma(current->mm, PAGE_SIZE); | |
89 | for (; vma; vma = vma->vm_next) { | |
90 | if (addr > limit) | |
91 | break; | |
92 | if (addr + len <= vma->vm_start) | |
93 | goto success; | |
94 | addr = vma->vm_end; | |
95 | } | |
96 | } | |
97 | } | |
98 | ||
99 | /* search from just above the WorkRAM area to the top of memory */ | |
100 | addr = PAGE_ALIGN(0x80000000); | |
101 | limit = TASK_SIZE - len; | |
102 | if (addr <= limit) { | |
103 | vma = find_vma(current->mm, addr); | |
104 | for (; vma; vma = vma->vm_next) { | |
105 | if (addr > limit) | |
106 | break; | |
107 | if (addr + len <= vma->vm_start) | |
108 | goto success; | |
109 | addr = vma->vm_end; | |
110 | } | |
111 | ||
112 | if (!vma && addr <= limit) | |
113 | goto success; | |
114 | } | |
115 | ||
116 | #if 0 | |
117 | printk("[area] l=%lx (ENOMEM) f='%s'\n", | |
1f70cecc | 118 | len, filp ? filp->f_path.dentry->d_name.name : ""); |
1da177e4 LT |
119 | #endif |
120 | return -ENOMEM; | |
121 | ||
122 | success: | |
123 | #if 0 | |
124 | printk("[area] l=%lx ad=%lx f='%s'\n", | |
1f70cecc | 125 | len, addr, filp ? filp->f_path.dentry->d_name.name : ""); |
1da177e4 LT |
126 | #endif |
127 | return addr; | |
128 | } /* end arch_get_unmapped_area() */ |