[linux-2.6-block.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/slab.h>
#include <linux/debugfs.h>
#include <asm/smp.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/firmware.h>
#include <asm/lppaca.h>

#include "plpar_wrappers.h"

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

#ifdef CONFIG_VIRT_CPU_ACCOUNTING
	/* disable this for now */
	return -ENODEV;
#endif

	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(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>
5a0e3ad6	24	#include <linux/slab.h>
fc59a3fc JK	25	#include <linux/debugfs.h>
	26	#include <asm/smp.h>
	27	#include <asm/system.h>
	28	#include <asm/uaccess.h>
b71a0c29	29	#include <asm/firmware.h>
cf9efce0	30	#include <asm/lppaca.h>
fc59a3fc JK	31
	32	#include "plpar_wrappers.h"
	33
fc59a3fc JK	34	struct dtl {
	35	struct dtl_entry *buf;
	36	struct dentry *file;
	37	int cpu;
	38	int buf_entries;
	39	u64 last_idx;
	40	};
6b7487fc	41	static DEFINE_PER_CPU(struct dtl, cpu_dtl);
fc59a3fc JK	42
	43	/*
	44	* Dispatch trace log event mask:
	45	* 0x7: 0x1: voluntary virtual processor waits
	46	* 0x2: time-slice preempts
	47	* 0x4: virtual partition memory page faults
	48	*/
	49	static u8 dtl_event_mask = 0x7;
	50
	51
	52	/*
	53	* Size of per-cpu log buffers. Default is just under 16 pages worth.
	54	*/
	55	static int dtl_buf_entries = (16 * 85);
	56
	57
	58	static int dtl_enable(struct dtl *dtl)
	59	{
	60	unsigned long addr;
	61	int ret, hwcpu;
	62
	63	/* only allow one reader */
	64	if (dtl->buf)
	65	return -EBUSY;
	66
	67	/* we need to store the original allocation size for use during read */
	68	dtl->buf_entries = dtl_buf_entries;
	69
	70	dtl->buf = kmalloc_node(dtl->buf_entries * sizeof(struct dtl_entry),
	71	GFP_KERNEL, cpu_to_node(dtl->cpu));
	72	if (!dtl->buf) {
	73	printk(KERN_WARNING "%s: buffer alloc failed for cpu %d\n",
	74	__func__, dtl->cpu);
	75	return -ENOMEM;
	76	}
	77
	78	/* Register our dtl buffer with the hypervisor. The HV expects the
	79	* buffer size to be passed in the second word of the buffer */
	80	((u32 )dtl->buf)[1] = dtl->buf_entries sizeof(struct dtl_entry);
	81
	82	hwcpu = get_hard_smp_processor_id(dtl->cpu);
	83	addr = __pa(dtl->buf);
	84	ret = register_dtl(hwcpu, addr);
	85	if (ret) {
	86	printk(KERN_WARNING "%s: DTL registration for cpu %d (hw %d) "
	87	"failed with %d\n", __func__, dtl->cpu, hwcpu, ret);
	88	kfree(dtl->buf);
	89	return -EIO;
	90	}
	91
	92	/* set our initial buffer indices */
8154c5d2	93	dtl->last_idx = lppaca_of(dtl->cpu).dtl_idx = 0;
fc59a3fc	94
82631f5d JK	95	/* ensure that our updates to the lppaca fields have occurred before
	96	* we actually enable the logging */
	97	smp_wmb();
	98
fc59a3fc	99	/* enable event logging */
8154c5d2	100	lppaca_of(dtl->cpu).dtl_enable_mask = dtl_event_mask;
fc59a3fc JK	101
	102	return 0;
	103	}
	104
	105	static void dtl_disable(struct dtl *dtl)
	106	{
	107	int hwcpu = get_hard_smp_processor_id(dtl->cpu);
	108
8154c5d2	109	lppaca_of(dtl->cpu).dtl_enable_mask = 0x0;
fc59a3fc JK	110
	111	unregister_dtl(hwcpu, __pa(dtl->buf));
	112
	113	kfree(dtl->buf);
	114	dtl->buf = NULL;
	115	dtl->buf_entries = 0;
	116	}
	117
	118	/* file interface */
	119
	120	static int dtl_file_open(struct inode inode, struct file filp)
	121	{
	122	struct dtl *dtl = inode->i_private;
	123	int rc;
	124
	125	rc = dtl_enable(dtl);
	126	if (rc)
	127	return rc;
	128
	129	filp->private_data = dtl;
	130	return 0;
	131	}
	132
	133	static int dtl_file_release(struct inode inode, struct file filp)
	134	{
	135	struct dtl *dtl = inode->i_private;
	136	dtl_disable(dtl);
	137	return 0;
	138	}
	139
	140	static ssize_t dtl_file_read(struct file filp, char __user buf, size_t len,
	141	loff_t *pos)
	142	{
	143	int rc, cur_idx, last_idx, n_read, n_req, read_size;
	144	struct dtl *dtl;
	145
	146	if ((len % sizeof(struct dtl_entry)) != 0)
	147	return -EINVAL;
	148
	149	dtl = filp->private_data;
	150
	151	/* requested number of entries to read */
	152	n_req = len / sizeof(struct dtl_entry);
	153
	154	/* actual number of entries read */
	155	n_read = 0;
	156
8154c5d2	157	cur_idx = lppaca_of(dtl->cpu).dtl_idx;
fc59a3fc JK	158	last_idx = dtl->last_idx;
	159
	160	if (cur_idx - last_idx > dtl->buf_entries) {
	161	pr_debug("%s: hv buffer overflow for cpu %d, samples lost\n",
	162	__func__, dtl->cpu);
	163	}
	164
	165	cur_idx %= dtl->buf_entries;
	166	last_idx %= dtl->buf_entries;
	167
	168	/* read the tail of the buffer if we've wrapped */
	169	if (last_idx > cur_idx) {
	170	read_size = min(n_req, dtl->buf_entries - last_idx);
	171
	172	rc = copy_to_user(buf, &dtl->buf[last_idx],
	173	read_size * sizeof(struct dtl_entry));
	174	if (rc)
	175	return -EFAULT;
	176
	177	last_idx = 0;
	178	n_req -= read_size;
	179	n_read += read_size;
	180	buf += read_size * sizeof(struct dtl_entry);
	181	}
	182
	183	/* .. and now the head */
	184	read_size = min(n_req, cur_idx - last_idx);
	185	rc = copy_to_user(buf, &dtl->buf[last_idx],
	186	read_size * sizeof(struct dtl_entry));
	187	if (rc)
	188	return -EFAULT;
	189
	190	n_read += read_size;
	191	dtl->last_idx += n_read;
	192
	193	return n_read * sizeof(struct dtl_entry);
	194	}
	195
828c0950	196	static const struct file_operations dtl_fops = {
fc59a3fc JK	197	.open = dtl_file_open,
	198	.release = dtl_file_release,
	199	.read = dtl_file_read,
	200	.llseek = no_llseek,
	201	};
	202
	203	static struct dentry *dtl_dir;
	204
	205	static int dtl_setup_file(struct dtl *dtl)
	206	{
	207	char name[10];
	208
	209	sprintf(name, "cpu-%d", dtl->cpu);
	210
	211	dtl->file = debugfs_create_file(name, 0400, dtl_dir, dtl, &dtl_fops);
	212	if (!dtl->file)
	213	return -ENOMEM;
	214
	215	return 0;
	216	}
	217
	218	static int dtl_init(void)
	219	{
	220	struct dentry event_mask_file, buf_entries_file;
	221	int rc, i;
	222
cf9efce0 PM	223	#ifdef CONFIG_VIRT_CPU_ACCOUNTING
	224	/* disable this for now */
	225	return -ENODEV;
	226	#endif
	227
fc59a3fc JK	228	if (!firmware_has_feature(FW_FEATURE_SPLPAR))
	229	return -ENODEV;
	230
	231	/* set up common debugfs structure */
	232
	233	rc = -ENOMEM;
	234	dtl_dir = debugfs_create_dir("dtl", powerpc_debugfs_root);
	235	if (!dtl_dir) {
	236	printk(KERN_WARNING "%s: can't create dtl root dir\n",
	237	__func__);
	238	goto err;
	239	}
	240
	241	event_mask_file = debugfs_create_x8("dtl_event_mask", 0600,
	242	dtl_dir, &dtl_event_mask);
	243	buf_entries_file = debugfs_create_u32("dtl_buf_entries", 0600,
	244	dtl_dir, &dtl_buf_entries);
	245
	246	if (!event_mask_file \|\| !buf_entries_file) {
	247	printk(KERN_WARNING "%s: can't create dtl files\n", __func__);
	248	goto err_remove_dir;
	249	}
	250
	251	/* set up the per-cpu log structures */
	252	for_each_possible_cpu(i) {
6b7487fc	253	struct dtl *dtl = &per_cpu(cpu_dtl, i);
fc59a3fc JK	254	dtl->cpu = i;
	255
	256	rc = dtl_setup_file(dtl);
	257	if (rc)
	258	goto err_remove_dir;
	259	}
	260
	261	return 0;
	262
	263	err_remove_dir:
	264	debugfs_remove_recursive(dtl_dir);
	265	err:
	266	return rc;
	267	}
	268	arch_initcall(dtl_init);