/*
   *  arch/um/kernel/elf_aux.c
   *
   *  Scan the Elf auxiliary vector provided by the host to extract
   *  information about vsyscall-page, etc.
   *
   *  Copyright (C) 2004 Fujitsu Siemens Computers GmbH
   *  Author: Bodo Stroesser (bodo.stroesser@fujitsu-siemens.com)
   */
  #include <elf.h>
  #include <stddef.h>
  #include "init.h"
  #include "elf_user.h"

  #include "mem_user.h"

  typedef Elf32_auxv_t elf_auxv_t;

  /* These are initialized very early in boot and never changed */

  char * elf_aux_platform;

  extern long elf_aux_hwcap;

  unsigned long vsyscall_ehdr;
  unsigned long vsyscall_end;

  unsigned long __kernel_vsyscall;
  
  __init void scan_elf_aux( char **envp)
  {
  	long page_size = 0;
  	elf_auxv_t * auxv;
  
  	while ( *envp++ != NULL) ;
  
  	for ( auxv = (elf_auxv_t *)envp; auxv->a_type != AT_NULL; auxv++) {
  		switch ( auxv->a_type ) {
  			case AT_SYSINFO:
  				__kernel_vsyscall = auxv->a_un.a_val;

  				/* See if the page is under TASK_SIZE */
  				if (__kernel_vsyscall < (unsigned long) envp)
  					__kernel_vsyscall = 0;

  				break;
  			case AT_SYSINFO_EHDR:
  				vsyscall_ehdr = auxv->a_un.a_val;

  				/* See if the page is under TASK_SIZE */
  				if (vsyscall_ehdr < (unsigned long) envp)
  					vsyscall_ehdr = 0;

  				break;
  			case AT_HWCAP:
  				elf_aux_hwcap = auxv->a_un.a_val;
  				break;
  			case AT_PLATFORM:

                                  /* elf.h removed the pointer elements from
                                   * a_un, so we have to use a_val, which is
                                   * all that's left.
                                   */

  				elf_aux_platform =
  					(char *) (long) auxv->a_un.a_val;

  				break;
  			case AT_PAGESZ:
  				page_size = auxv->a_un.a_val;
  				break;
  		}
  	}
  	if ( ! __kernel_vsyscall || ! vsyscall_ehdr ||
  	     ! elf_aux_hwcap || ! elf_aux_platform ||
  	     ! page_size || (vsyscall_ehdr % page_size) ) {
  		__kernel_vsyscall = 0;
  		vsyscall_ehdr = 0;
  		elf_aux_hwcap = 0;
  		elf_aux_platform = "i586";
  	}
  	else {
  		vsyscall_end = vsyscall_ehdr + page_size;
  	}
  }