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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; | |
e759a798 | 63 | struct vm_unmapped_area_info info; |
1da177e4 LT |
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 */ | |
e759a798 ML |
82 | info.flags = 0; |
83 | info.length = len; | |
84 | info.low_limit = PAGE_SIZE; | |
85 | info.high_limit = (current->mm->start_stack - 0x00200000); | |
86 | info.align_mask = 0; | |
87 | info.align_offset = 0; | |
88 | addr = vm_unmapped_area(&info); | |
89 | if (!(addr & ~PAGE_MASK)) | |
90 | goto success; | |
91 | VM_BUG_ON(addr != -ENOMEM); | |
1da177e4 LT |
92 | |
93 | /* search from just above the WorkRAM area to the top of memory */ | |
e759a798 ML |
94 | info.low_limit = PAGE_ALIGN(0x80000000); |
95 | info.high_limit = TASK_SIZE; | |
96 | addr = vm_unmapped_area(&info); | |
97 | if (!(addr & ~PAGE_MASK)) | |
98 | goto success; | |
99 | VM_BUG_ON(addr != -ENOMEM); | |
1da177e4 LT |
100 | |
101 | #if 0 | |
102 | printk("[area] l=%lx (ENOMEM) f='%s'\n", | |
1f70cecc | 103 | len, filp ? filp->f_path.dentry->d_name.name : ""); |
1da177e4 LT |
104 | #endif |
105 | return -ENOMEM; | |
106 | ||
107 | success: | |
108 | #if 0 | |
109 | printk("[area] l=%lx ad=%lx f='%s'\n", | |
1f70cecc | 110 | len, addr, filp ? filp->f_path.dentry->d_name.name : ""); |
1da177e4 LT |
111 | #endif |
112 | return addr; | |
113 | } /* end arch_get_unmapped_area() */ |