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#include <asm/mman.h>
17
18/*****************************************************************************/
19/*
20 * lay out the userspace VM according to our grand design
21 */
22#ifdef CONFIG_MMU
23void 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 */
59unsigned 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
68	/* handle MAP_FIXED */
69	if (flags & MAP_FIXED)
70		return addr;
71
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	return -ENOMEM;
117
118 success:
119	return addr;
120} /* end arch_get_unmapped_area() */
121