source: bootcd/isolinux/syslinux-6.03/gpxe/src/image/segment.c

/*
 * Copyright (C) 2007 Michael Brown <mbrown@fensystems.co.uk>.
 *
 * 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 any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

FILE_LICENCE ( GPL2_OR_LATER );

/**
 * @file
 *
 * Executable image segments
 *
 */

#include <errno.h>
#include <gpxe/uaccess.h>
#include <gpxe/memmap.h>
#include <gpxe/errortab.h>
#include <gpxe/segment.h>

/**
 * Prepare segment for loading
 *
 * @v segment           Segment start
 * @v filesz            Size of the "allocated bytes" portion of the segment
 * @v memsz             Size of the segment
 * @ret rc              Return status code
 */
int prep_segment ( userptr_t segment, size_t filesz, size_t memsz ) {
        struct memory_map memmap;
        physaddr_t start = user_to_phys ( segment, 0 );
        physaddr_t mid = user_to_phys ( segment, filesz );
        physaddr_t end = user_to_phys ( segment, memsz );
        unsigned int i;

        DBG ( "Preparing segment [%lx,%lx,%lx)\n", start, mid, end );

        /* Sanity check */
        if ( filesz > memsz ) {
                DBG ( "Insane segment [%lx,%lx,%lx)\n", start, mid, end );
                return -EINVAL;
        }

        /* Get a fresh memory map.  This allows us to automatically
         * avoid treading on any regions that Etherboot is currently
         * editing out of the memory map.
         */
        get_memmap ( &memmap );

        /* Look for a suitable memory region */
        for ( i = 0 ; i < memmap.count ; i++ ) {
                if ( ( start >= memmap.regions[i].start ) &&
                     ( end <= memmap.regions[i].end ) ) {
                        /* Found valid region: zero bss and return */
                        memset_user ( segment, filesz, 0, ( memsz - filesz ) );
                        return 0;
                }
        }

        /* No suitable memory region found */
        DBG ( "Segment [%lx,%lx,%lx) does not fit into available memory\n",
              start, mid, end );
        return -ERANGE;
}

/**
 * Segment-specific error messages
 *
 * This error happens sufficiently often to merit a user-friendly
 * description.
 */
struct errortab segment_errors[] __errortab = {
        { ERANGE, "Requested memory not available" },
};