/*
 * Copyright (C) 2012 Red Hat, Inc.
 * Copyright (C) 2012 Jeremy Kerr <jeremy.kerr@canonical.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/efi.h>
#include <linux/fs.h>
#include <linux/ctype.h>
#include <linux/slab.h>
#include <linux/uuid.h>

#include "internal.h"

struct inode *efivarfs_get_inode(struct super_block *sb,
				const struct inode *dir, int mode,
				dev_t dev, bool is_removable)
{
	struct inode *inode = new_inode(sb);

	if (inode) {
		inode->i_ino = get_next_ino();
		inode->i_mode = mode;
		inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
		inode->i_flags = is_removable ? 0 : S_IMMUTABLE;
		switch (mode & S_IFMT) {
		case S_IFREG:
			inode->i_fop = &efivarfs_file_operations;
			break;
		case S_IFDIR:
			inode->i_op = &efivarfs_dir_inode_operations;
			inode->i_fop = &simple_dir_operations;
			inc_nlink(inode);
			break;
		}
	}
	return inode;
}

/*
 * Return true if 'str' is a valid efivarfs filename of the form,
 *
 *	VariableName-12345678-1234-1234-1234-1234567891bc
 */
bool efivarfs_valid_name(const char *str, int len)
{
	const char *s = str + len - EFI_VARIABLE_GUID_LEN;

	/*
	 * We need a GUID, plus at least one letter for the variable name,
	 * plus the '-' separator
	 */
	if (len < EFI_VARIABLE_GUID_LEN + 2)
		return false;

	/* GUID must be preceded by a '-' */
	if (*(s - 1) != '-')
		return false;

	/*
	 * Validate that 's' is of the correct format, e.g.
	 *
	 *	12345678-1234-1234-1234-123456789abc
	 */
	return uuid_is_valid(s);
}

static int efivarfs_create(struct inode *dir, struct dentry *dentry,
			  umode_t mode, bool excl)
{
	struct inode *inode = NULL;
	struct efivar_entry *var;
	int namelen, i = 0, err = 0;
	bool is_removable = false;

	if (!efivarfs_valid_name(dentry->d_name.name, dentry->d_name.len))
		return -EINVAL;

	var = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
	if (!var)
		return -ENOMEM;

	/* length of the variable name itself: remove GUID and separator */
	namelen = dentry->d_name.len - EFI_VARIABLE_GUID_LEN - 1;

	uuid_le_to_bin(dentry->d_name.name + namelen + 1, &var->var.VendorGuid);

	if (efivar_variable_is_removable(var->var.VendorGuid,
					 dentry->d_name.name, namelen))
		is_removable = true;

	inode = efivarfs_get_inode(dir->i_sb, dir, mode, 0, is_removable);
	if (!inode) {
		err = -ENOMEM;
		goto out;
	}

	for (i = 0; i < namelen; i++)
		var->var.VariableName[i] = dentry->d_name.name[i];

	var->var.VariableName[i] = '\0';

	inode->i_private = var;

	err = efivar_entry_add(var, &efivarfs_list);
	if (err)
		goto out;

	d_instantiate(dentry, inode);
	dget(dentry);
out:
	if (err) {
		kfree(var);
		if (inode)
			iput(inode);
	}
	return err;
}

static int efivarfs_unlink(struct inode *dir, struct dentry *dentry)
{
	struct efivar_entry *var = d_inode(dentry)->i_private;

	if (efivar_entry_delete(var))
		return -EINVAL;

	drop_nlink(d_inode(dentry));
	dput(dentry);
	return 0;
};

const struct inode_operations efivarfs_dir_inode_operations = {
	.lookup = simple_lookup,
	.unlink = efivarfs_unlink,
	.create = efivarfs_create,
};
='/cgit.cgi/linux/net-next.git/commit/security/tomoyo/policy?id=6e978b22efa1db9f6e71b24440b5f1d93e968ee3'>policy</a>/<a href='/cgit.cgi/linux/net-next.git/commit/security/tomoyo/policy/exception_policy.conf.default?id=6e978b22efa1db9f6e71b24440b5f1d93e968ee3'>exception_policy.conf.default</a></div><div class='content'><div class='cgit-panel'><b>diff options</b><form method='get'><input type='hidden' name='id' value='6e978b22efa1db9f6e71b24440b5f1d93e968ee3'/><table><tr><td colspan='2'/></tr><tr><td class='label'>context:</td><td class='ctrl'><select name='context' onchange='this.form.submit();'><option value='1'>1</option><option value='2'>2</option><option value='3' selected='selected'>3</option><option value='4'>4</option><option value='5'>5</option><option value='6'>6</option><option value='7'>7</option><option value='8'>8</option><option value='9'>9</option><option value='10'>10</option><option value='15'>15</option><option value='20'>20</option><option value='25'>25</option><option value='30'>30</option><option value='35'>35</option><option 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/security/tomoyo/policy/exception_policy.conf.default?id=6e978b22efa1db9f6e71b24440b5f1d93e968ee3'>6e978b22efa1db9f6e71b24440b5f1d93e968ee3</a> (<a href='/cgit.cgi/linux/net-next.git/patch/security/tomoyo/policy/exception_policy.conf.default?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> /<a href='/cgit.cgi/linux/net-next.git/tree/security/tomoyo/policy/exception_policy.conf.default?id=6e978b22efa1db9f6e71b24440b5f1d93e968ee3'>security/tomoyo/policy/exception_policy.conf.default</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/security/tomoyo/policy/exception_policy.conf.default?id=3c223c19aea85d3dda1416c187915f4a30b04b1f'>3c223c19aea85d3dda1416c187915f4a30b04b1f</a> (<a href='/cgit.cgi/linux/net-next.git/diff/security/tomoyo/policy/exception_policy.conf.default?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> (limited to 'security/tomoyo/policy/exception_policy.conf.default')</div><table summary='diffstat' class='diffstat'>