[deliverable/linux.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 <linux/spinlock.h>
#include <asm/smp.h>
#include <asm/uaccess.h>
#include <asm/firmware.h>
#include <asm/lppaca.h>
#include <asm/debug.h>
#include <asm/plpar_wrappers.h>

struct dtl {
	struct dtl_entry	*buf;
	struct dentry		*file;
	int			cpu;
	int			buf_entries;
	u64			last_idx;
	spinlock_t		lock;
};
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. Firmware requires that the buffer does
 * not cross a 4k boundary.
 */
static int dtl_buf_entries = N_DISPATCH_LOG;

#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
struct dtl_ring {
	u64	write_index;
	struct dtl_entry *write_ptr;
	struct dtl_entry *buf;
	struct dtl_entry *buf_end;
	u8	saved_dtl_mask;
};

static DEFINE_PER_CPU(struct dtl_ring, dtl_rings);

static atomic_t dtl_count;

/*
 * The cpu accounting code controls the DTL ring buffer, and we get
 * given entries as they are processed.
 */
static void consume_dtle(struct dtl_entry *dtle, u64 index)
{
	struct dtl_ring *dtlr = &__get_cpu_var(dtl_rings);
	struct dtl_entry *wp = dtlr->write_ptr;
	struct lppaca *vpa = local_paca->lppaca_ptr;

	if (!wp)
		return;

	*wp = *dtle;
	barrier();

	/* check for hypervisor ring buffer overflow, ignore this entry if so */
	if (index + N_DISPATCH_LOG < be64_to_cpu(vpa->dtl_idx))
		return;

	++wp;
	if (wp == dtlr->buf_end)
		wp = dtlr->buf;
	dtlr->write_ptr = wp;

	/* incrementing write_index makes the new entry visible */
	smp_wmb();
	++dtlr->write_index;
}

static int dtl_start(struct dtl *dtl)
{
	struct dtl_ring *dtlr = &per_cpu(dtl_rings, dtl->cpu);

	dtlr->buf = dtl->buf;
	dtlr->buf_end = dtl->buf + dtl->buf_entries;
	dtlr->write_index = 0;

	/* setting write_ptr enables logging into our buffer */
	smp_wmb();
	dtlr->write_ptr = dtl->buf;

	/* enable event logging */
	dtlr->saved_dtl_mask = lppaca_of(dtl->cpu).dtl_enable_mask;
	lppaca_of(dtl->cpu).dtl_enable_mask |= dtl_event_mask;

	dtl_consumer = consume_dtle;
	atomic_inc(&dtl_count);
	return 0;
}

static void dtl_stop(struct dtl *dtl)
{
	struct dtl_ring *dtlr = &per_cpu(dtl_rings, dtl->cpu);

	dtlr->write_ptr = NULL;
	smp_wmb();

	dtlr->buf = NULL;

	/* restore dtl_enable_mask */
	lppaca_of(dtl->cpu).dtl_enable_mask = dtlr->saved_dtl_mask;

	if (atomic_dec_and_test(&dtl_count))
		dtl_consumer = NULL;
}

static u64 dtl_current_index(struct dtl *dtl)
{
	return per_cpu(dtl_rings, dtl->cpu).write_index;
}

#else /* CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */

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

	/* 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] = DISPATCH_LOG_BYTES;

	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);
		return -EIO;
	}

	/* set our initial buffer indices */
	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_stop(struct dtl *dtl)
{
	int hwcpu = get_hard_smp_processor_id(dtl->cpu);

	lppaca_of(dtl->cpu).dtl_enable_mask = 0x0;

	unregister_dtl(hwcpu);
}

static u64 dtl_current_index(struct dtl *dtl)
{
	return lppaca_of(dtl->cpu).dtl_idx;
}
#endif /* CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */

static int dtl_enable(struct dtl *dtl)
{
	long int n_entries;
	long int rc;
	struct dtl_entry *buf = NULL;

	if (!dtl_cache)
		return -ENOMEM;

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

	n_entries = dtl_buf_entries;
	buf = kmem_cache_alloc_node(dtl_cache, GFP_KERNEL, cpu_to_node(dtl->cpu));
	if (!buf) {
		printk(KERN_WARNING "%s: buffer alloc failed for cpu %d\n",
				__func__, dtl->cpu);
		return -ENOMEM;
	}

	spin_lock(&dtl->lock);
	rc = -EBUSY;
	if (!dtl->buf) {
		/* store the original allocation size for use during read */
		dtl->buf_entries = n_entries;
		dtl->buf = buf;
		dtl->last_idx = 0;
		rc = dtl_start(dtl);
		if (rc)
			dtl->buf = NULL;
	}
	spin_unlock(&dtl->lock);

	if (rc)
		kmem_cache_free(dtl_cache, buf);
	return rc;
}

static void dtl_disable(struct dtl *dtl)
{
	spin_lock(&dtl->lock);
	dtl_stop(dtl);
	kmem_cache_free(dtl_cache, dtl->buf);
	dtl->buf = NULL;
	dtl->buf_entries = 0;
	spin_unlock(&dtl->lock);
}

/* 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)
{
	long int rc, n_read, n_req, read_size;
	struct dtl *dtl;
	u64 cur_idx, last_idx, i;

	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;

	spin_lock(&dtl->lock);

	cur_idx = dtl_current_index(dtl);
	last_idx = dtl->last_idx;

	if (last_idx + dtl->buf_entries <= cur_idx)
		last_idx = cur_idx - dtl->buf_entries + 1;

	if (last_idx + n_req > cur_idx)
		n_req = cur_idx - last_idx;

	if (n_req > 0)
		dtl->last_idx = last_idx + n_req;

	spin_unlock(&dtl->lock);

	if (n_req <= 0)
		return 0;

	i = last_idx % dtl->buf_entries;

	/* read the tail of the buffer if we've wrapped */
	if (i + n_req > dtl->buf_entries) {
		read_size = dtl->buf_entries - i;

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

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

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

	n_read += n_req;

	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;

	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", 0400,
				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);
		spin_lock_init(&dtl->lock);
		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	25	#include <linux/debugfs.h>
872e439a	26	#include <linux/spinlock.h>
fc59a3fc	27	#include <asm/smp.h>
fc59a3fc	28	#include <asm/uaccess.h>
b71a0c29	29	#include <asm/firmware.h>
cf9efce0	30	#include <asm/lppaca.h>
ae3a197e	31	#include <asm/debug.h>
212bebb4	32	#include <asm/plpar_wrappers.h>
fc59a3fc	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;
872e439a	40	spinlock_t lock;
fc59a3fc	41	};
6b7487fc	42	static DEFINE_PER_CPU(struct dtl, cpu_dtl);
fc59a3fc JK	43
	44	/*
	45	* Dispatch trace log event mask:
	46	* 0x7: 0x1: voluntary virtual processor waits
	47	* 0x2: time-slice preempts
	48	* 0x4: virtual partition memory page faults
	49	*/
	50	static u8 dtl_event_mask = 0x7;
	51
	52
	53	/*
af442a1b NA	54	* Size of per-cpu log buffers. Firmware requires that the buffer does
af442a1b NA	55	* not cross a 4k boundary.
fc59a3fc	56	*/
af442a1b	57	static int dtl_buf_entries = N_DISPATCH_LOG;
fc59a3fc	58
abf917cd	59	#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
872e439a PM	60	struct dtl_ring {
	61	u64 write_index;
	62	struct dtl_entry *write_ptr;
	63	struct dtl_entry *buf;
	64	struct dtl_entry *buf_end;
	65	u8 saved_dtl_mask;
	66	};
	67
	68	static DEFINE_PER_CPU(struct dtl_ring, dtl_rings);
	69
	70	static atomic_t dtl_count;
	71
	72	/*
	73	* The cpu accounting code controls the DTL ring buffer, and we get
	74	* given entries as they are processed.
	75	*/
	76	static void consume_dtle(struct dtl_entry *dtle, u64 index)
fc59a3fc	77	{
872e439a PM	78	struct dtl_ring *dtlr = &__get_cpu_var(dtl_rings);
	79	struct dtl_entry *wp = dtlr->write_ptr;
	80	struct lppaca *vpa = local_paca->lppaca_ptr;
fc59a3fc	81
872e439a PM	82	if (!wp)
872e439a PM	83	return;
fc59a3fc	84
872e439a PM	85	wp = dtle;
872e439a PM	86	barrier();
fc59a3fc	87
872e439a	88	/* check for hypervisor ring buffer overflow, ignore this entry if so */
7ffcf8ec	89	if (index + N_DISPATCH_LOG < be64_to_cpu(vpa->dtl_idx))
872e439a PM	90	return;
	91
	92	++wp;
	93	if (wp == dtlr->buf_end)
	94	wp = dtlr->buf;
	95	dtlr->write_ptr = wp;
	96
	97	/* incrementing write_index makes the new entry visible */
	98	smp_wmb();
	99	++dtlr->write_index;
	100	}
	101
	102	static int dtl_start(struct dtl *dtl)
	103	{
	104	struct dtl_ring *dtlr = &per_cpu(dtl_rings, dtl->cpu);
	105
	106	dtlr->buf = dtl->buf;
	107	dtlr->buf_end = dtl->buf + dtl->buf_entries;
	108	dtlr->write_index = 0;
	109
	110	/* setting write_ptr enables logging into our buffer */
	111	smp_wmb();
	112	dtlr->write_ptr = dtl->buf;
	113
	114	/* enable event logging */
	115	dtlr->saved_dtl_mask = lppaca_of(dtl->cpu).dtl_enable_mask;
	116	lppaca_of(dtl->cpu).dtl_enable_mask \|= dtl_event_mask;
	117
	118	dtl_consumer = consume_dtle;
	119	atomic_inc(&dtl_count);
	120	return 0;
	121	}
	122
	123	static void dtl_stop(struct dtl *dtl)
	124	{
	125	struct dtl_ring *dtlr = &per_cpu(dtl_rings, dtl->cpu);
	126
	127	dtlr->write_ptr = NULL;
	128	smp_wmb();
	129
	130	dtlr->buf = NULL;
	131
	132	/* restore dtl_enable_mask */
	133	lppaca_of(dtl->cpu).dtl_enable_mask = dtlr->saved_dtl_mask;
	134
	135	if (atomic_dec_and_test(&dtl_count))
	136	dtl_consumer = NULL;
	137	}
	138
	139	static u64 dtl_current_index(struct dtl *dtl)
	140	{
	141	return per_cpu(dtl_rings, dtl->cpu).write_index;
	142	}
	143
abf917cd	144	#else /* CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
872e439a PM	145
	146	static int dtl_start(struct dtl *dtl)
	147	{
	148	unsigned long addr;
	149	int ret, hwcpu;
fc59a3fc JK	150
	151	/* Register our dtl buffer with the hypervisor. The HV expects the
	152	* buffer size to be passed in the second word of the buffer */
af442a1b	153	((u32 *)dtl->buf)[1] = DISPATCH_LOG_BYTES;
fc59a3fc JK	154
	155	hwcpu = get_hard_smp_processor_id(dtl->cpu);
	156	addr = __pa(dtl->buf);
	157	ret = register_dtl(hwcpu, addr);
	158	if (ret) {
	159	printk(KERN_WARNING "%s: DTL registration for cpu %d (hw %d) "
	160	"failed with %d\n", __func__, dtl->cpu, hwcpu, ret);
fc59a3fc JK	161	return -EIO;
	162	}
	163
	164	/* set our initial buffer indices */
872e439a	165	lppaca_of(dtl->cpu).dtl_idx = 0;
fc59a3fc	166
82631f5d JK	167	/* ensure that our updates to the lppaca fields have occurred before
	168	* we actually enable the logging */
	169	smp_wmb();
	170
fc59a3fc	171	/* enable event logging */
8154c5d2	172	lppaca_of(dtl->cpu).dtl_enable_mask = dtl_event_mask;
fc59a3fc JK	173
	174	return 0;
	175	}
	176
872e439a	177	static void dtl_stop(struct dtl *dtl)
fc59a3fc JK	178	{
	179	int hwcpu = get_hard_smp_processor_id(dtl->cpu);
	180
8154c5d2	181	lppaca_of(dtl->cpu).dtl_enable_mask = 0x0;
fc59a3fc	182
b1301797	183	unregister_dtl(hwcpu);
872e439a PM	184	}
	185
	186	static u64 dtl_current_index(struct dtl *dtl)
	187	{
	188	return lppaca_of(dtl->cpu).dtl_idx;
	189	}
abf917cd	190	#endif /* CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
fc59a3fc	191
872e439a PM	192	static int dtl_enable(struct dtl *dtl)
	193	{
	194	long int n_entries;
	195	long int rc;
	196	struct dtl_entry *buf = NULL;
	197
af442a1b NA	198	if (!dtl_cache)
	199	return -ENOMEM;
	200
872e439a PM	201	/* only allow one reader */
	202	if (dtl->buf)
	203	return -EBUSY;
	204
	205	n_entries = dtl_buf_entries;
af442a1b	206	buf = kmem_cache_alloc_node(dtl_cache, GFP_KERNEL, cpu_to_node(dtl->cpu));
872e439a PM	207	if (!buf) {
	208	printk(KERN_WARNING "%s: buffer alloc failed for cpu %d\n",
	209	__func__, dtl->cpu);
	210	return -ENOMEM;
	211	}
	212
	213	spin_lock(&dtl->lock);
	214	rc = -EBUSY;
	215	if (!dtl->buf) {
	216	/* store the original allocation size for use during read */
	217	dtl->buf_entries = n_entries;
	218	dtl->buf = buf;
	219	dtl->last_idx = 0;
	220	rc = dtl_start(dtl);
	221	if (rc)
	222	dtl->buf = NULL;
	223	}
	224	spin_unlock(&dtl->lock);
	225
	226	if (rc)
af442a1b	227	kmem_cache_free(dtl_cache, buf);
872e439a PM	228	return rc;
	229	}
	230
	231	static void dtl_disable(struct dtl *dtl)
	232	{
	233	spin_lock(&dtl->lock);
	234	dtl_stop(dtl);
af442a1b	235	kmem_cache_free(dtl_cache, dtl->buf);
fc59a3fc JK	236	dtl->buf = NULL;
fc59a3fc JK	237	dtl->buf_entries = 0;
872e439a	238	spin_unlock(&dtl->lock);
fc59a3fc JK	239	}
	240
	241	/* file interface */
	242
	243	static int dtl_file_open(struct inode inode, struct file filp)
	244	{
	245	struct dtl *dtl = inode->i_private;
	246	int rc;
	247
	248	rc = dtl_enable(dtl);
	249	if (rc)
	250	return rc;
	251
	252	filp->private_data = dtl;
	253	return 0;
	254	}
	255
	256	static int dtl_file_release(struct inode inode, struct file filp)
	257	{
	258	struct dtl *dtl = inode->i_private;
	259	dtl_disable(dtl);
	260	return 0;
	261	}
	262
	263	static ssize_t dtl_file_read(struct file filp, char __user buf, size_t len,
	264	loff_t *pos)
	265	{
872e439a	266	long int rc, n_read, n_req, read_size;
fc59a3fc	267	struct dtl *dtl;
872e439a	268	u64 cur_idx, last_idx, i;
fc59a3fc JK	269
	270	if ((len % sizeof(struct dtl_entry)) != 0)
	271	return -EINVAL;
	272
	273	dtl = filp->private_data;
	274
	275	/* requested number of entries to read */
	276	n_req = len / sizeof(struct dtl_entry);
	277
	278	/* actual number of entries read */
	279	n_read = 0;
	280
872e439a PM	281	spin_lock(&dtl->lock);
	282
	283	cur_idx = dtl_current_index(dtl);
fc59a3fc JK	284	last_idx = dtl->last_idx;
fc59a3fc JK	285
872e439a PM	286	if (last_idx + dtl->buf_entries <= cur_idx)
	287	last_idx = cur_idx - dtl->buf_entries + 1;
	288
	289	if (last_idx + n_req > cur_idx)
	290	n_req = cur_idx - last_idx;
fc59a3fc	291
872e439a PM	292	if (n_req > 0)
	293	dtl->last_idx = last_idx + n_req;
	294
	295	spin_unlock(&dtl->lock);
	296
	297	if (n_req <= 0)
	298	return 0;
	299
	300	i = last_idx % dtl->buf_entries;
fc59a3fc JK	301
fc59a3fc JK	302	/* read the tail of the buffer if we've wrapped */
872e439a PM	303	if (i + n_req > dtl->buf_entries) {
872e439a PM	304	read_size = dtl->buf_entries - i;
fc59a3fc	305
872e439a	306	rc = copy_to_user(buf, &dtl->buf[i],
fc59a3fc JK	307	read_size * sizeof(struct dtl_entry));
	308	if (rc)
	309	return -EFAULT;
	310
872e439a	311	i = 0;
fc59a3fc JK	312	n_req -= read_size;
	313	n_read += read_size;
	314	buf += read_size * sizeof(struct dtl_entry);
	315	}
	316
	317	/* .. and now the head */
872e439a	318	rc = copy_to_user(buf, &dtl->buf[i], n_req * sizeof(struct dtl_entry));
fc59a3fc JK	319	if (rc)
	320	return -EFAULT;
	321
872e439a	322	n_read += n_req;
fc59a3fc JK	323
	324	return n_read * sizeof(struct dtl_entry);
	325	}
	326
828c0950	327	static const struct file_operations dtl_fops = {
fc59a3fc JK	328	.open = dtl_file_open,
	329	.release = dtl_file_release,
	330	.read = dtl_file_read,
	331	.llseek = no_llseek,
	332	};
	333
	334	static struct dentry *dtl_dir;
	335
	336	static int dtl_setup_file(struct dtl *dtl)
	337	{
	338	char name[10];
	339
	340	sprintf(name, "cpu-%d", dtl->cpu);
	341
	342	dtl->file = debugfs_create_file(name, 0400, dtl_dir, dtl, &dtl_fops);
	343	if (!dtl->file)
	344	return -ENOMEM;
	345
	346	return 0;
	347	}
	348
	349	static int dtl_init(void)
	350	{
	351	struct dentry event_mask_file, buf_entries_file;
	352	int rc, i;
	353
	354	if (!firmware_has_feature(FW_FEATURE_SPLPAR))
	355	return -ENODEV;
	356
	357	/* set up common debugfs structure */
	358
	359	rc = -ENOMEM;
	360	dtl_dir = debugfs_create_dir("dtl", powerpc_debugfs_root);
	361	if (!dtl_dir) {
	362	printk(KERN_WARNING "%s: can't create dtl root dir\n",
	363	__func__);
	364	goto err;
	365	}
	366
	367	event_mask_file = debugfs_create_x8("dtl_event_mask", 0600,
	368	dtl_dir, &dtl_event_mask);
af442a1b	369	buf_entries_file = debugfs_create_u32("dtl_buf_entries", 0400,
fc59a3fc JK	370	dtl_dir, &dtl_buf_entries);
	371
	372	if (!event_mask_file \|\| !buf_entries_file) {
	373	printk(KERN_WARNING "%s: can't create dtl files\n", __func__);
	374	goto err_remove_dir;
	375	}
	376
	377	/* set up the per-cpu log structures */
	378	for_each_possible_cpu(i) {
6b7487fc	379	struct dtl *dtl = &per_cpu(cpu_dtl, i);
872e439a	380	spin_lock_init(&dtl->lock);
fc59a3fc JK	381	dtl->cpu = i;
	382
	383	rc = dtl_setup_file(dtl);
	384	if (rc)
	385	goto err_remove_dir;
	386	}
	387
	388	return 0;
	389
	390	err_remove_dir:
	391	debugfs_remove_recursive(dtl_dir);
	392	err:
	393	return rc;
	394	}
	395	arch_initcall(dtl_init);