/* nommu.c: mmu-less memory info files
 *
 * 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/init.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/time.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/mman.h>
#include <linux/proc_fs.h>
#include <linux/mm.h>
#include <linux/mmzone.h>
#include <linux/pagemap.h>
#include <linux/swap.h>
#include <linux/smp.h>
#include <linux/seq_file.h>
#include <linux/hugetlb.h>
#include <linux/vmalloc.h>
#include <linux/uaccess.h>
#include <asm/pgtable.h>
#include <asm/tlb.h>
#include <asm/div64.h>
#include "internal.h"

/*
 * display a single region to a sequenced file
 */
static int nommu_region_show(struct seq_file *m, struct vm_region *region)
{
	unsigned long ino = 0;
	struct file *file;
	dev_t dev = 0;
	int flags;

	flags = region->vm_flags;
	file = region->vm_file;

	if (file) {
		struct inode *inode = file_inode(region->vm_file);
		dev = inode->i_sb->s_dev;
		ino = inode->i_ino;
	}

	seq_setwidth(m, 25 + sizeof(void *) * 6 - 1);
	seq_printf(m,
		   "%08lx-%08lx %c%c%c%c %08llx %02x:%02x %lu ",
		   region->vm_start,
		   region->vm_end,
		   flags & VM_READ ? 'r' : '-',
		   flags & VM_WRITE ? 'w' : '-',
		   flags & VM_EXEC ? 'x' : '-',
		   flags & VM_MAYSHARE ? flags & VM_SHARED ? 'S' : 's' : 'p',
		   ((loff_t)region->vm_pgoff) << PAGE_SHIFT,
		   MAJOR(dev), MINOR(dev), ino);

	if (file) {
		seq_pad(m, ' ');
		seq_file_path(m, file, "");
	}

	seq_putc(m, '\n');
	return 0;
}

/*
 * display a list of all the REGIONs the kernel knows about
 * - nommu kernels have a single flat list
 */
static int nommu_region_list_show(struct seq_file *m, void *_p)
{
	struct rb_node *p = _p;

	return nommu_region_show(m, rb_entry(p, struct vm_region, vm_rb));
}

static void *nommu_region_list_start(struct seq_file *m, loff_t *_pos)
{
	struct rb_node *p;
	loff_t pos = *_pos;

	down_read(&nommu_region_sem);

	for (p = rb_first(&nommu_region_tree); p; p = rb_next(p))
		if (pos-- == 0)
			return p;
	return NULL;
}

static void nommu_region_list_stop(struct seq_file *m, void *v)
{
	up_read(&nommu_region_sem);
}

static void *nommu_region_list_next(struct seq_file *m, void *v, loff_t *pos)
{
	(*pos)++;
	return rb_next((struct rb_node *) v);
}

static const struct seq_operations proc_nommu_region_list_seqop = {
	.start	= nommu_region_list_start,
	.next	= nommu_region_list_next,
	.stop	= nommu_region_list_stop,
	.show	= nommu_region_list_show
};

static int proc_nommu_region_list_open(struct inode *inode, struct file *file)
{
	return seq_open(file, &proc_nommu_region_list_seqop);
}

static const struct file_operations proc_nommu_region_list_operations = {
	.open    = proc_nommu_region_list_open,
	.read    = seq_read,
	.llseek  = seq_lseek,
	.release = seq_release,
};

static int __init proc_nommu_init(void)
{
	proc_create("maps", S_IRUGO, NULL, &proc_nommu_region_list_operations);
	return 0;
}

fs_initcall(proc_nommu_init);
 value='40'>40</option></select></td></tr><tr><td class='label'>space:</td><td class='ctrl'><select name='ignorews' onchange='this.form.submit();'><option value='0' selected='selected'>include</option><option value='1'>ignore</option></select></td></tr><tr><td class='label'>mode:</td><td class='ctrl'><select name='dt' onchange='this.form.submit();'><option value='0' selected='selected'>unified</option><option value='1'>ssdiff</option><option value='2'>stat only</option></select></td></tr><tr><td/><td class='ctrl'><noscript><input type='submit' value='reload'/></noscript></td></tr></table></form></div><table summary='commit info' class='commit-info'>
<tr><th>author</th><td>Srinivas Pandruvada &lt;srinivas.pandruvada@linux.intel.com&gt;</td><td class='right'>2017-02-03 14:18:39 -0800</td></tr>
<tr><th>committer</th><td>Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;</td><td class='right'>2017-02-04 00:11:08 +0100</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/?id=6e978b22efa1db9f6e71b24440b5f1d93e968ee3'>6e978b22efa1db9f6e71b24440b5f1d93e968ee3</a> (<a href='/cgit.cgi/linux/net-next.git/patch/?id=6e978b22efa1db9f6e71b24440b5f1d93e968ee3'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?id=6e978b22efa1db9f6e71b24440b5f1d93e968ee3'>c666f7a26b860674848949e39a610222b0723f89</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/?id=3c223c19aea85d3dda1416c187915f4a30b04b1f'>3c223c19aea85d3dda1416c187915f4a30b04b1f</a> (<a href='/cgit.cgi/linux/net-next.git/diff/?id=6e978b22efa1db9f6e71b24440b5f1d93e968ee3&amp;id2=3c223c19aea85d3dda1416c187915f4a30b04b1f'>diff</a>)</td></tr></table>
<div class='commit-subject'>cpufreq: intel_pstate: Disable energy efficiency optimization</div><div class='commit-msg'>Some Kabylake desktop processors may not reach max turbo when running in
HWP mode, even if running under sustained 100% utilization.

This occurs when the HWP.EPP (Energy Performance Preference) is set to
"balance_power" (0x80) -- the default on most systems.

It occurs because the platform BIOS may erroneously enable an
energy-efficiency setting -- MSR_IA32_POWER_CTL BIT-EE, which is not
recommended to be enabled on this SKU.

On the failing systems, this BIOS issue was not discovered when the
desktop motherboard was tested with Windows, because the BIOS also
neglects to provide the ACPI/CPPC table, that Windows requires to enable
HWP, and so Windows runs in legacy P-state mode, where this setting has
no effect.

Linux' intel_pstate driver does not require ACPI/CPPC to enable HWP, and
so it runs in HWP mode, exposing this incorrect BIOS configuration.

There are several ways to address this problem.

First, Linux can also run in legacy P-state mode on this system.
As intel_pstate is how Linux enables HWP, booting with
"intel_pstate=disable"
will run in acpi-cpufreq/ondemand legacy p-state mode.

Or second, the "performance" governor can be used with intel_pstate,
which will modify HWP.EPP to 0.

Or third, starting in 4.10, the
/sys/devices/system/cpu/cpufreq/policy*/energy_performance_preference
attribute in can be updated from "balance_power" to "performance".

Or fourth, apply this patch, which fixes the erroneous setting of
MSR_IA32_POWER_CTL BIT_EE on this model, allowing the default
configuration to function as designed.

Signed-off-by: Srinivas Pandruvada &lt;srinivas.pandruvada@linux.intel.com&gt;
Reviewed-by: Len Brown &lt;len.brown@intel.com&gt;
Cc: 4.6+ &lt;stable@vger.kernel.org&gt; # 4.6+
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=6e978b22efa1db9f6e71b24440b5f1d93e968ee3'>Diffstat</a></div><table summary='diffstat' class='diffstat'>