/*
 * Copyright 2012  Google, Inc.
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * 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.
 */

#include <linux/kernel.h>
#include <linux/compiler.h>
#include <linux/irqflags.h>
#include <linux/percpu.h>
#include <linux/smp.h>
#include <linux/atomic.h>
#include <linux/types.h>
#include <linux/mutex.h>
#include <linux/ftrace.h>
#include <linux/fs.h>
#include <linux/debugfs.h>
#include <linux/err.h>
#include <linux/cache.h>
#include <asm/barrier.h>
#include "internal.h"

/* This doesn't need to be atomic: speed is chosen over correctness here. */
static u64 pstore_ftrace_stamp;

static void notrace pstore_ftrace_call(unsigned long ip,
				       unsigned long parent_ip,
				       struct ftrace_ops *op,
				       struct pt_regs *regs)
{
	unsigned long flags;
	struct pstore_ftrace_record rec = {};

	if (unlikely(oops_in_progress))
		return;

	local_irq_save(flags);

	rec.ip = ip;
	rec.parent_ip = parent_ip;
	pstore_ftrace_write_timestamp(&rec, pstore_ftrace_stamp++);
	pstore_ftrace_encode_cpu(&rec, raw_smp_processor_id());
	psinfo->write_buf(PSTORE_TYPE_FTRACE, 0, NULL, 0, (void *)&rec,
			  0, sizeof(rec), psinfo);

	local_irq_restore(flags);
}

static struct ftrace_ops pstore_ftrace_ops __read_mostly = {
	.func	= pstore_ftrace_call,
};

static DEFINE_MUTEX(pstore_ftrace_lock);
static bool pstore_ftrace_enabled;

static ssize_t pstore_ftrace_knob_write(struct file *f, const char __user *buf,
					size_t count, loff_t *ppos)
{
	u8 on;
	ssize_t ret;

	ret = kstrtou8_from_user(buf, count, 2, &on);
	if (ret)
		return ret;

	mutex_lock(&pstore_ftrace_lock);

	if (!on ^ pstore_ftrace_enabled)
		goto out;

	if (on) {
		ftrace_ops_set_global_filter(&pstore_ftrace_ops);
		ret = register_ftrace_function(&pstore_ftrace_ops);
	} else {
		ret = unregister_ftrace_function(&pstore_ftrace_ops);
	}

	if (ret) {
		pr_err("%s: unable to %sregister ftrace ops: %zd\n",
		       __func__, on ? "" : "un", ret);
		goto err;
	}

	pstore_ftrace_enabled = on;
out:
	ret = count;
err:
	mutex_unlock(&pstore_ftrace_lock);

	return ret;
}

static ssize_t pstore_ftrace_knob_read(struct file *f, char __user *buf,
				       size_t count, loff_t *ppos)
{
	char val[] = { '0' + pstore_ftrace_enabled, '\n' };

	return simple_read_from_buffer(buf, count, ppos, val, sizeof(val));
}

static const struct file_operations pstore_knob_fops = {
	.open	= simple_open,
	.read	= pstore_ftrace_knob_read,
	.write	= pstore_ftrace_knob_write,
};

static struct dentry *pstore_ftrace_dir;

void pstore_register_ftrace(void)
{
	struct dentry *file;

	if (!psinfo->write_buf)
		return;

	pstore_ftrace_dir = debugfs_create_dir("pstore", NULL);
	if (!pstore_ftrace_dir) {
		pr_err("%s: unable to create pstore directory\n", __func__);
		return;
	}

	file = debugfs_create_file("record_ftrace", 0600, pstore_ftrace_dir,
				   NULL, &pstore_knob_fops);
	if (!file) {
		pr_err("%s: unable to create record_ftrace file\n", __func__);
		goto err_file;
	}

	return;
err_file:
	debugfs_remove(pstore_ftrace_dir);
}

void pstore_unregister_ftrace(void)
{
	mutex_lock(&pstore_ftrace_lock);
	if (pstore_ftrace_enabled) {
		unregister_ftrace_function(&pstore_ftrace_ops);
		pstore_ftrace_enabled = 0;
	}
	mutex_unlock(&pstore_ftrace_lock);

	debugfs_remove_recursive(pstore_ftrace_dir);
}
method='get'><input type='hidden' name='h' value='nds-private-remove'/><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/sound/soc/omap/mcbsp.h?h=nds-private-remove&amp;id=6e978b22efa1db9f6e71b24440b5f1d93e968ee3'>6e978b22efa1db9f6e71b24440b5f1d93e968ee3</a> (<a href='/cgit.cgi/linux/net-next.git/patch/sound/soc/omap/mcbsp.h?id=6e978b22efa1db9f6e71b24440b5f1d93e968ee3'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?h=nds-private-remove&amp;id=6e978b22efa1db9f6e71b24440b5f1d93e968ee3'>c666f7a26b860674848949e39a610222b0723f89</a> /<a href='/cgit.cgi/linux/net-next.git/tree/sound/soc/omap/mcbsp.h?h=nds-private-remove&amp;id=6e978b22efa1db9f6e71b24440b5f1d93e968ee3'>sound/soc/omap/mcbsp.h</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/sound/soc/omap/mcbsp.h?h=nds-private-remove&amp;id=3c223c19aea85d3dda1416c187915f4a30b04b1f'>3c223c19aea85d3dda1416c187915f4a30b04b1f</a> (<a href='/cgit.cgi/linux/net-next.git/diff/sound/soc/omap/mcbsp.h?h=nds-private-remove&amp;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/?h=nds-private-remove&amp;id=6e978b22efa1db9f6e71b24440b5f1d93e968ee3'>Diffstat</a> (limited to 'sound/soc/omap/mcbsp.h')</div><table summary='diffstat' class='diffstat'>