path: root/arch/x86/kernel/cpu/mtrr/cleanup.c

/*  MTRR (Memory Type Range Register) cleanup

    Copyright (C) 2009 Yinghai Lu

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Library General Public
    License as published by the Free Software Foundation; either
    version 2 of the License, or (at your option) any later version.

    This library 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
    Library General Public License for more details.

    You should have received a copy of the GNU Library General Public
    License along with this library; if not, write to the Free
    Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include <linux/module.h>
#include <linux/init.h>
#include <linux/pci.h>
#include <linux/smp.h>
#include <linux/cpu.h>
#include <linux/mutex.h>
#include <linux/sort.h>

#include <asm/e820.h>
#include <asm/mtrr.h>
#include <asm/uaccess.h>
#include <asm/processor.h>
#include <asm/msr.h>
#include <asm/kvm_para.h>
#include "mtrr.h"

/* should be related to MTRR_VAR_RANGES nums */
#define RANGE_NUM 256

struct res_range {
	unsigned long start;
	unsigned long end;
};

static int __init
add_range(struct res_range *range, int nr_range, unsigned long start,
			      unsigned long end)
{
	/* out of slots */
	if (nr_range >= RANGE_NUM)
		return nr_range;

	range[nr_range].start = start;
	range[nr_range].end = end;

	nr_range++;

	return nr_range;
}

static int __init
add_range_with_merge(struct res_range *range, int nr_range, unsigned long start,
			      unsigned long end)
{
	int i;

	/* try to merge it with old one */
	for (i = 0; i < nr_range; i++) {
		unsigned long final_start, final_end;
		unsigned long common_start, common_end;

		if (!range[i].end)
			continue;

		common_start = max(range[i].start, start);
		common_end = min(range[i].end, end);
		if (common_start > common_end + 1)
			continue;

		final_start = min(range[i].start, start);
		final_end = max(range[i].end, end);

		range[i].start = final_start;
		range[i].end =  final_end;
		return nr_range;
	}

	/* need to add that */
	return add_range(range, nr_range, start, end);
}

static void __init
subtract_range(struct res_range *range, unsigned long start, unsigned long end)
{
	int i, j;

	for (j = 0; j < RANGE_NUM; j++) {
		if (!range[j].end)
			continue;

		if (start <= range[j].start && end >= range[j].end) {
			range[j].start = 0;
			range[j].end = 0;
			continue;
		}

		if (start <= range[j].start && end < range[j].end &&
		    range[j].start < end + 1) {
			range[j].start = end + 1;
			continue;
		}


		if (start > range[j].start && end >= range[j].end &&
		    range[j].end > start - 1) {
			range[j].end = start - 1;
			continue;
		}

		if (start > range[j].start && end < range[j].end) {
			/* find the new spare */
			for (i = 0; i <