release/src-rt-6.x.4708/linux/linux-2.6.36/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
  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
  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() */