/*- * Copyright (c) 2007-2008 *      Bill Paul <wpaul@windriver.com>.  All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright *    notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright *    notice, this list of conditions and the following disclaimer in the *    documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software *    must display the following acknowledgement: *      This product includes software developed by Bill Paul. * 4. Neither the name of the author nor the names of any co-contributors *    may be used to endorse or promote products derived from this software *    without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY Bill Paul AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED.  IN NO EVENT SHALL Bill Paul OR THE VOICES IN HIS HEAD * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF * THE POSSIBILITY OF SUCH DAMAGE. */#include "types.h"#include "data.h"#include "stand.h"/* * This module updates the page tables so that we can map additional * memory. With x86-64, paging is required when running in long mode, * which means we must have page tables, and those page tables consume * RAM, so we want to keep them small. The minimum case requires 3 * 4K page directories: one level 4 top level directory, one level 3 * directory, and one level 2 directory. We can set the page attribute * bits in the level 2 directory to use 2MB pages, which, with 512 * page table entries, allows us to map 1GB of RAM. That's enough to * get started, but eventually we want more. That means we have to add * more 2nd level page tables to map additional RAM. To avoid trampling * over too much memory to begin with, we leave the startup page table * in place until after we've dumped the first 640K of RAM. After that, * we're free to scribble on it, and we can add in some more pages. */extern p3_entry_t PT3[]; p2_entry_t * l2map = (p2_entry_t *)PAGE_TABLES;#define MAPS	63#define PTES	512void mapmem (void){	int		i;	bzero ((char *)l2map, sizeof(p2_entry_t) * 512 * MAPS);	/* Populate page tables */	for (i = 0; i < PTES * MAPS; i++) {		l2map[i] = (512 + i) * (2 * 1024 * 1024);		l2map[i] |= PG_V | PG_RW | PG_PS | PG_U;	}	/* Add them to the level 3 page directory */	for (i = 0; i < MAPS; i++) {		PT3[i + 1] = (p3_entry_t)((uintptr_t)(l2map + (i * 512)));		PT3[i + 1] |= PG_V | PG_RW | PG_U;	}	return;}