text: /* elf-fdpic.c: ELF FDPIC memory layout management
   *
   * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
   * Written by David Howells (dhowells@redhat.com)
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public License
   * as published by the Free Software Foundation; either version
   * 2 of the License, or (at your option) any later version.
   */
  
  #include <linux/sched.h>
  #include <linux/mm.h>
  #include <linux/fs.h>
  #include <linux/elf-fdpic.h>
  #include <asm/mman.h>
  
  /*****************************************************************************/
  /*
   * lay out the userspace VM according to our grand design
   */
  #ifdef CONFIG_MMU
  void elf_fdpic_arch_lay_out_mm(struct elf_fdpic_params *exec_params,
  			       struct elf_fdpic_params *interp_params,
  			       unsigned long *start_stack,
  			       unsigned long *start_brk)
  {
  	*start_stack = 0x02200000UL;
  
  	/* if the only executable is a shared object, assume that it is an interpreter rather than
  	 * a true executable, and map it such that "ld.so --list" comes out right
  	 */
  	if (!(interp_params->flags & ELF_FDPIC_FLAG_PRESENT) &&
  	    exec_params->hdr.e_type != ET_EXEC
  	    ) {
  		exec_params->load_addr = PAGE_SIZE;
  
  		*start_brk = 0x80000000UL;
  	}
  	else {
  		exec_params->load_addr = 0x02200000UL;
  
  		if ((exec_params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) ==
  		    ELF_FDPIC_FLAG_INDEPENDENT
  		    ) {
  			exec_params->flags &= ~ELF_FDPIC_FLAG_ARRANGEMENT;
  			exec_params->flags |= ELF_FDPIC_FLAG_CONSTDISP;
  		}
  	}
  
  } /* end elf_fdpic_arch_lay_out_mm() */
  #endif
  
  /*****************************************************************************/
  /*
   * place non-fixed mmaps firstly in the bottom part of memory, working up, and then in the top part
   * of memory, working down
   */
  unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr, unsigned long len,
  				     unsigned long pgoff, unsigned long flags)
  {
  	struct vm_area_struct *vma;
  	unsigned long limit;
  
  	if (len > TASK_SIZE)
  		return -ENOMEM;
  
  	/* handle MAP_FIXED */
  	if (flags & MAP_FIXED)
  		return addr;
  
  	/* only honour a hint if we're not going to clobber something doing so */
  	if (addr) {
  		addr = PAGE_ALIGN(addr);
  		vma = find_vma(current->mm, addr);
  		if (TASK_SIZE - len >= addr &&
  		    (!vma || addr + len <= vm_start_gap(vma)))
  			goto success;
  	}
  
  	/* search between the bottom of user VM and the stack grow area */
  	addr = PAGE_SIZE;
  	limit = (current->mm->start_stack - 0x00200000);
  	if (addr + len <= limit) {
  		limit -= len;
  
  		if (addr <= limit) {
  			vma = find_vma(current->mm, PAGE_SIZE);
  			for (; vma; vma = vma->vm_next) {
  				if (addr > limit)
  					break;
  				if (addr + len <= vma->vm_start)
  					goto success;
  				addr = vma->vm_end;
  			}
  		}
  	}
  
  	/* search from just above the WorkRAM area to the top of memory */
  	addr = PAGE_ALIGN(0x80000000);
  	limit = TASK_SIZE - len;
  	if (addr <= limit) {
  		vma = find_vma(current->mm, addr);
  		for (; vma; vma = vma->vm_next) {
  			if (addr > limit)
  				break;
  			if (addr + len <= vma->vm_start)
  				goto success;
  			addr = vma->vm_end;
  		}
  
  		if (!vma && addr <= limit)
  			goto success;
  	}
  
  #if 0
  	printk("[area] l=%lx (ENOMEM) f='%s'\n",
  	       len, filp ? filp->f_path.dentry->d_name.name : "");
  #endif
  	return -ENOMEM;
  
   success:
  #if 0
  	printk("[area] l=%lx ad=%lx f='%s'\n",
  	       len, addr, filp ? filp->f_path.dentry->d_name.name : "");
  #endif
  	return addr;
  } /* end arch_get_unmapped_area() */
  