[GitHub/mt8127/android_kernel_alcatel_ttab.git] / arch / powerpc / platforms / pseries / dtl.c

/*
 * Virtual Processor Dispatch Trace Log
 *
 * (C) Copyright IBM Corporation 2009
 *
 * Author: Jeremy Kerr <jk@ozlabs.org>
 *
 * 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, or (at your option)
 * any later version.
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/init.h>
#include <linux/debugfs.h>
#include <asm/smp.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/firmware.h>

#include "plpar_wrappers.h"

/*
 * Layout of entries in the hypervisor's DTL buffer. Although we don't
 * actually access the internals of an entry (we only need to know the size),
 * we might as well define it here for reference.
 */
struct dtl_entry {
	u8	dispatch_reason;
	u8	preempt_reason;
	u16	processor_id;
	u32	enqueue_to_dispatch_time;
	u32	ready_to_enqueue_time;
	u32	waiting_to_ready_time;
	u64	timebase;
	u64	fault_addr;
	u64	srr0;
	u64	srr1;
};

struct dtl {
	struct dtl_entry	*buf;
	struct dentry		*file;
	int			cpu;
	int			buf_entries;
	u64			last_idx;
};
static DEFINE_PER_CPU(struct dtl, dtl);

/*
 * Dispatch trace log event mask:
 * 0x7: 0x1: voluntary virtual processor waits
 *      0x2: time-slice preempts
 *      0x4: virtual partition memory page faults
 */
static u8 dtl_event_mask = 0x7;


/*
 * Size of per-cpu log buffers. Default is just under 16 pages worth.
 */
static int dtl_buf_entries = (16 * 85);


static int dtl_enable(struct dtl *dtl)
{
	unsigned long addr;
	int ret, hwcpu;

	/* only allow one reader */
	if (dtl->buf)
		return -EBUSY;

	/* we need to store the original allocation size for use during read */
	dtl->buf_entries = dtl_buf_entries;

	dtl->buf = kmalloc_node(dtl->buf_entries * sizeof(struct dtl_entry),
			GFP_KERNEL, cpu_to_node(dtl->cpu));
	if (!dtl->buf) {
		printk(KERN_WARNING "%s: buffer alloc failed for cpu %d\n",
				__func__, dtl->cpu);
		return -ENOMEM;
	}

	/* Register our dtl buffer with the hypervisor. The HV expects the
	 * buffer size to be passed in the second word of the buffer */
	((u32 *)dtl->buf)[1] = dtl->buf_entries * sizeof(struct dtl_entry);

	hwcpu = get_hard_smp_processor_id(dtl->cpu);
	addr = __pa(dtl->buf);
	ret = register_dtl(hwcpu, addr);
	if (ret) {
		printk(KERN_WARNING "%s: DTL registration for cpu %d (hw %d) "
		       "failed with %d\n", __func__, dtl->cpu, hwcpu, ret);
		kfree(dtl->buf);
		return -EIO;
	}

	/* set our initial buffer indices */
	dtl->last_idx = lppaca[dtl->cpu].dtl_idx = 0;

	/* ensure that our updates to the lppaca fields have occurred before
	 * we actually enable the logging */
	smp_wmb();

	/* enable event logging */
	lppaca[dtl->cpu].dtl_enable_mask = dtl_event_mask;

	return 0;
}

static void dtl_disable(struct dtl *dtl)
{
	int hwcpu = get_hard_smp_processor_id(dtl->cpu);

	lppaca[dtl->cpu].dtl_enable_mask = 0x0;

	unregister_dtl(hwcpu, __pa(dtl->buf));

	kfree(dtl->buf);
	dtl->buf = NULL;
	dtl->buf_entries = 0;
}

/* file interface */

static int dtl_file_open(struct inode *inode, struct file *filp)
{
	struct dtl *dtl = inode->i_private;
	int rc;

	rc = dtl_enable(dtl);
	if (rc)
		return rc;

	filp->private_data = dtl;
	return 0;
}

static int dtl_file_release(struct inode *inode, struct file *filp)
{
	struct dtl *dtl = inode->i_private;
	dtl_disable(dtl);
	return 0;
}

static ssize_t dtl_file_read(struct file *filp, char __user *buf, size_t len,
		loff_t *pos)
{
	int rc, cur_idx, last_idx, n_read, n_req, read_size;
	struct dtl *dtl;

	if ((len % sizeof(struct dtl_entry)) != 0)
		return -EINVAL;

	dtl = filp->private_data;

	/* requested number of entries to read */
	n_req = len / sizeof(struct dtl_entry);

	/* actual number of entries read */
	n_read = 0;

	cur_idx = lppaca[dtl->cpu].dtl_idx;
	last_idx = dtl->last_idx;

	if (cur_idx - last_idx > dtl->buf_entries) {
		pr_debug("%s: hv buffer overflow for cpu %d, samples lost\n",
				__func__, dtl->cpu);
	}

	cur_idx  %= dtl->buf_entries;
	last_idx %= dtl->buf_entries;

	/* read the tail of the buffer if we've wrapped */
	if (last_idx > cur_idx) {
		read_size = min(n_req, dtl->buf_entries - last_idx);

		rc = copy_to_user(buf, &dtl->buf[last_idx],
				read_size * sizeof(struct dtl_entry));
		if (rc)
			return -EFAULT;

		last_idx = 0;
		n_req -= read_size;
		n_read += read_size;
		buf += read_size * sizeof(struct dtl_entry);
	}

	/* .. and now the head */
	read_size = min(n_req, cur_idx - last_idx);
	rc = copy_to_user(buf, &dtl->buf[last_idx],
			read_size * sizeof(struct dtl_entry));
	if (rc)
		return -EFAULT;

	n_read += read_size;
	dtl->last_idx += n_read;

	return n_read * sizeof(struct dtl_entry);
}

static struct file_operations dtl_fops = {
	.open		= dtl_file_open,
	.release	= dtl_file_release,
	.read		= dtl_file_read,
	.llseek		= no_llseek,
};

static struct dentry *dtl_dir;

static int dtl_setup_file(struct dtl *dtl)
{
	char name[10];

	sprintf(name, "cpu-%d", dtl->cpu);

	dtl->file = debugfs_create_file(name, 0400, dtl_dir, dtl, &dtl_fops);
	if (!dtl->file)
		return -ENOMEM;

	return 0;
}

static int dtl_init(void)
{
	struct dentry *event_mask_file, *buf_entries_file;
	int rc, i;

	if (!firmware_has_feature(FW_FEATURE_SPLPAR))
		return -ENODEV;

	/* set up common debugfs structure */

	rc = -ENOMEM;
	dtl_dir = debugfs_create_dir("dtl", powerpc_debugfs_root);
	if (!dtl_dir) {
		printk(KERN_WARNING "%s: can't create dtl root dir\n",
				__func__);
		goto err;
	}

	event_mask_file = debugfs_create_x8("dtl_event_mask", 0600,
				dtl_dir, &dtl_event_mask);
	buf_entries_file = debugfs_create_u32("dtl_buf_entries", 0600,
				dtl_dir, &dtl_buf_entries);

	if (!event_mask_file || !buf_entries_file) {
		printk(KERN_WARNING "%s: can't create dtl files\n", __func__);
		goto err_remove_dir;
	}

	/* set up the per-cpu log structures */
	for_each_possible_cpu(i) {
		struct dtl *dtl = &per_cpu(dtl, i);
		dtl->cpu = i;

		rc = dtl_setup_file(dtl);
		if (rc)
			goto err_remove_dir;
	}

	return 0;

err_remove_dir:
	debugfs_remove_recursive(dtl_dir);
err:
	return rc;
}
arch_initcall(dtl_init);
Commit	Line	Data
fc59a3fc JK	1	/*
	2	* Virtual Processor Dispatch Trace Log
	3	*
	4	* (C) Copyright IBM Corporation 2009
	5	*
	6	* Author: Jeremy Kerr <jk@ozlabs.org>
	7	*
	8	* This program is free software; you can redistribute it and/or modify
	9	* it under the terms of the GNU General Public License as published by
	10	* the Free Software Foundation; either version 2, or (at your option)
	11	* any later version.
	12	*
	13	* This program is distributed in the hope that it will be useful,
	14	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	15	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	16	* GNU General Public License for more details.
	17	*
	18	* You should have received a copy of the GNU General Public License
	19	* along with this program; if not, write to the Free Software
	20	* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
	21	*/
	22
	23	#include <linux/init.h>
	24	#include <linux/debugfs.h>
	25	#include <asm/smp.h>
	26	#include <asm/system.h>
	27	#include <asm/uaccess.h>
b71a0c29	28	#include <asm/firmware.h>
fc59a3fc JK	29
	30	#include "plpar_wrappers.h"
	31
	32	/*
	33	* Layout of entries in the hypervisor's DTL buffer. Although we don't
	34	* actually access the internals of an entry (we only need to know the size),
	35	* we might as well define it here for reference.
	36	*/
	37	struct dtl_entry {
	38	u8 dispatch_reason;
	39	u8 preempt_reason;
	40	u16 processor_id;
	41	u32 enqueue_to_dispatch_time;
	42	u32 ready_to_enqueue_time;
	43	u32 waiting_to_ready_time;
	44	u64 timebase;
	45	u64 fault_addr;
	46	u64 srr0;
	47	u64 srr1;
	48	};
	49
	50	struct dtl {
	51	struct dtl_entry *buf;
	52	struct dentry *file;
	53	int cpu;
	54	int buf_entries;
	55	u64 last_idx;
	56	};
	57	static DEFINE_PER_CPU(struct dtl, dtl);
	58
	59	/*
	60	* Dispatch trace log event mask:
	61	* 0x7: 0x1: voluntary virtual processor waits
	62	* 0x2: time-slice preempts
	63	* 0x4: virtual partition memory page faults
	64	*/
	65	static u8 dtl_event_mask = 0x7;
	66
	67
	68	/*
	69	* Size of per-cpu log buffers. Default is just under 16 pages worth.
	70	*/
	71	static int dtl_buf_entries = (16 * 85);
	72
	73
	74	static int dtl_enable(struct dtl *dtl)
	75	{
	76	unsigned long addr;
	77	int ret, hwcpu;
	78
	79	/* only allow one reader */
	80	if (dtl->buf)
	81	return -EBUSY;
	82
	83	/* we need to store the original allocation size for use during read */
	84	dtl->buf_entries = dtl_buf_entries;
	85
	86	dtl->buf = kmalloc_node(dtl->buf_entries * sizeof(struct dtl_entry),
	87	GFP_KERNEL, cpu_to_node(dtl->cpu));
	88	if (!dtl->buf) {
	89	printk(KERN_WARNING "%s: buffer alloc failed for cpu %d\n",
	90	__func__, dtl->cpu);
	91	return -ENOMEM;
	92	}
93
94	/* Register our dtl buffer with the hypervisor. The HV expects the
95	* buffer size to be passed in the second word of the buffer */
96	((u32 )dtl->buf)[1] = dtl->buf_entries sizeof(struct dtl_entry);
97
98	hwcpu = get_hard_smp_processor_id(dtl->cpu);
99	addr = __pa(dtl->buf);
100	ret = register_dtl(hwcpu, addr);
101	if (ret) {
102	printk(KERN_WARNING "%s: DTL registration for cpu %d (hw %d) "
103	"failed with %d\n", __func__, dtl->cpu, hwcpu, ret);
104	kfree(dtl->buf);
105	return -EIO;
106	}
107
108	/* set our initial buffer indices */
109	dtl->last_idx = lppaca[dtl->cpu].dtl_idx = 0;
110
82631f5d JK	111	/* ensure that our updates to the lppaca fields have occurred before
	112	* we actually enable the logging */
	113	smp_wmb();
	114
fc59a3fc JK	115	/* enable event logging */
	116	lppaca[dtl->cpu].dtl_enable_mask = dtl_event_mask;
	117
	118	return 0;
	119	}
	120
	121	static void dtl_disable(struct dtl *dtl)
	122	{
	123	int hwcpu = get_hard_smp_processor_id(dtl->cpu);
	124
	125	lppaca[dtl->cpu].dtl_enable_mask = 0x0;
	126
	127	unregister_dtl(hwcpu, __pa(dtl->buf));
	128
	129	kfree(dtl->buf);
	130	dtl->buf = NULL;
	131	dtl->buf_entries = 0;
	132	}
	133
	134	/* file interface */
	135
	136	static int dtl_file_open(struct inode inode, struct file filp)
	137	{
	138	struct dtl *dtl = inode->i_private;
	139	int rc;
	140
	141	rc = dtl_enable(dtl);
	142	if (rc)
	143	return rc;
	144
	145	filp->private_data = dtl;
	146	return 0;
	147	}
	148
	149	static int dtl_file_release(struct inode inode, struct file filp)
	150	{
	151	struct dtl *dtl = inode->i_private;
	152	dtl_disable(dtl);
	153	return 0;
	154	}
	155
	156	static ssize_t dtl_file_read(struct file filp, char __user buf, size_t len,
	157	loff_t *pos)
	158	{
	159	int rc, cur_idx, last_idx, n_read, n_req, read_size;
	160	struct dtl *dtl;
	161
	162	if ((len % sizeof(struct dtl_entry)) != 0)
	163	return -EINVAL;
	164
	165	dtl = filp->private_data;
	166
	167	/* requested number of entries to read */
	168	n_req = len / sizeof(struct dtl_entry);
	169
	170	/* actual number of entries read */
	171	n_read = 0;
	172
	173	cur_idx = lppaca[dtl->cpu].dtl_idx;
	174	last_idx = dtl->last_idx;
	175
	176	if (cur_idx - last_idx > dtl->buf_entries) {
	177	pr_debug("%s: hv buffer overflow for cpu %d, samples lost\n",
	178	__func__, dtl->cpu);
179	}
180
181	cur_idx %= dtl->buf_entries;
182	last_idx %= dtl->buf_entries;
183
184	/* read the tail of the buffer if we've wrapped */
185	if (last_idx > cur_idx) {
186	read_size = min(n_req, dtl->buf_entries - last_idx);
187
188	rc = copy_to_user(buf, &dtl->buf[last_idx],
189	read_size * sizeof(struct dtl_entry));
190	if (rc)
191	return -EFAULT;
192
193	last_idx = 0;
194	n_req -= read_size;
195	n_read += read_size;
196	buf += read_size * sizeof(struct dtl_entry);
197	}
198
199	/* .. and now the head */
200	read_size = min(n_req, cur_idx - last_idx);
201	rc = copy_to_user(buf, &dtl->buf[last_idx],
202	read_size * sizeof(struct dtl_entry));
203	if (rc)
204	return -EFAULT;
205
206	n_read += read_size;
207	dtl->last_idx += n_read;
208
209	return n_read * sizeof(struct dtl_entry);
210	}
211
212	static struct file_operations dtl_fops = {
213	.open = dtl_file_open,
214	.release = dtl_file_release,
215	.read = dtl_file_read,
216	.llseek = no_llseek,
217	};
218
219	static struct dentry *dtl_dir;
220
221	static int dtl_setup_file(struct dtl *dtl)
222	{
223	char name[10];
224
225	sprintf(name, "cpu-%d", dtl->cpu);
226
227	dtl->file = debugfs_create_file(name, 0400, dtl_dir, dtl, &dtl_fops);
228	if (!dtl->file)
229	return -ENOMEM;
230
231	return 0;
232	}
233
234	static int dtl_init(void)
235	{
236	struct dentry event_mask_file, buf_entries_file;
237	int rc, i;
238
239	if (!firmware_has_feature(FW_FEATURE_SPLPAR))
240	return -ENODEV;
241
242	/* set up common debugfs structure */
243
244	rc = -ENOMEM;
245	dtl_dir = debugfs_create_dir("dtl", powerpc_debugfs_root);
246	if (!dtl_dir) {
247	printk(KERN_WARNING "%s: can't create dtl root dir\n",
248	__func__);
249	goto err;
250	}
251
252	event_mask_file = debugfs_create_x8("dtl_event_mask", 0600,
253	dtl_dir, &dtl_event_mask);
254	buf_entries_file = debugfs_create_u32("dtl_buf_entries", 0600,
255	dtl_dir, &dtl_buf_entries);
256
257	if (!event_mask_file \|\| !buf_entries_file) {
258	printk(KERN_WARNING "%s: can't create dtl files\n", __func__);
259	goto err_remove_dir;
260	}
261
262	/* set up the per-cpu log structures */
263	for_each_possible_cpu(i) {
264	struct dtl *dtl = &per_cpu(dtl, i);
265	dtl->cpu = i;
266
267	rc = dtl_setup_file(dtl);
268	if (rc)
269	goto err_remove_dir;
270	}
271
272	return 0;
273
274	err_remove_dir:
275	debugfs_remove_recursive(dtl_dir);
276	err:
277	return rc;
278	}
279	arch_initcall(dtl_init);