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
  17 /*****************************************************************************/
  18 /*
  19  * lay out the userspace VM according to our grand design
  20  */
  21 #ifdef CONFIG_MMU
  22 void elf_fdpic_arch_lay_out_mm(struct elf_fdpic_params *exec_params,
  23                                struct elf_fdpic_params *interp_params,
  24                                unsigned long *start_stack,
  25                                unsigned long *start_brk)
  26 {
  27         *start_stack = 0x02200000UL;
  28
  29         /* if the only executable is a shared object, assume that it is an interpreter rather than
  30          * a true executable, and map it such that "ld.so --list" comes out right
  31          */
  32         if (!(interp_params->flags & ELF_FDPIC_FLAG_PRESENT) &&
  33             exec_params->hdr.e_type != ET_EXEC
  34             ) {
  35                 exec_params->load_addr = PAGE_SIZE;
  36
  37                 *start_brk = 0x80000000UL;
  38         }
  39         else {
  40                 exec_params->load_addr = 0x02200000UL;
  41
  42                 if ((exec_params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) ==
  43                     ELF_FDPIC_FLAG_INDEPENDENT
  44                     ) {
  45                         exec_params->flags &= ~ELF_FDPIC_FLAG_ARRANGEMENT;
  46                         exec_params->flags |= ELF_FDPIC_FLAG_CONSTDISP;
  47                 }
  48         }
  49
  50 } /* end elf_fdpic_arch_lay_out_mm() */
  51 #endif
  52
  53 /*****************************************************************************/
  54 /*
  55  * place non-fixed mmaps firstly in the bottom part of memory, working up, and then in the top part
  56  * of memory, working down
  57  */
  58 unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr, unsigned long len,
  59                                      unsigned long pgoff, unsigned long flags)
  60 {
  61         struct vm_area_struct *vma;
  62         unsigned long limit;
  63
  64         if (len > TASK_SIZE)
  65                 return -ENOMEM;
  66
  67         /* only honour a hint if we're not going to clobber something doing so */
  68         if (addr) {
  69                 addr = PAGE_ALIGN(addr);
  70                 vma = find_vma(current->mm, addr);
  71                 if (TASK_SIZE - len >= addr &&
  72                     (!vma || addr + len <= vma->vm_start))
  73                         goto success;
  74         }
  75
  76         /* search between the bottom of user VM and the stack grow area */
  77         addr = PAGE_SIZE;
  78         limit = (current->mm->start_stack - 0x00200000);
  79         if (addr + len <= limit) {
  80                 limit -= len;
  81
  82                 if (addr <= limit) {
  83                         vma = find_vma(current->mm, PAGE_SIZE);
  84                         for (; vma; vma = vma->vm_next) {
  85                                 if (addr > limit)
  86                                         break;
  87                                 if (addr + len <= vma->vm_start)
  88                                         goto success;
  89                                 addr = vma->vm_end;
  90                         }
  91                 }
  92         }
  93
  94         /* search from just above the WorkRAM area to the top of memory */
  95         addr = PAGE_ALIGN(0x80000000);
  96         limit = TASK_SIZE - len;
  97         if (addr <= limit) {
  98                 vma = find_vma(current->mm, addr);
  99                 for (; vma; vma = vma->vm_next) {
 100                         if (addr > limit)
 101                                 break;
 102                         if (addr + len <= vma->vm_start)
 103                                 goto success;
 104                         addr = vma->vm_end;
 105                 }
 106
 107                 if (!vma && addr <= limit)
 108                         goto success;
 109         }
 110
 111 #if 0
 112         printk("[area] l=%lx (ENOMEM) f='%s'\n",
 113                len, filp ? filp->f_dentry->d_name.name : "");
 114 #endif
 115         return -ENOMEM;
 116
 117  success:
 118 #if 0
 119         printk("[area] l=%lx ad=%lx f='%s'\n",
 120                len, addr, filp ? filp->f_dentry->d_name.name : "");
 121 #endif
 122         return addr;
 123 } /* end arch_get_unmapped_area() */