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