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