LXR linux/arch/frv/mm/elf-fdpic.c

   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#if 0
 117        printk("[area] l=%lx (ENOMEM) f='%s'\n",
 118               len, filp ? filp->f_path.dentry->d_name.name : "");
 119#endif
 120        return -ENOMEM;
 121
 122 success:
 123#if 0
 124        printk("[area] l=%lx ad=%lx f='%s'\n",
 125               len, addr, filp ? filp->f_path.dentry->d_name.name : "");
 126#endif
 127        return addr;
 128} /* end arch_get_unmapped_area() */
 129