aboutsummaryrefslogtreecommitdiff
path: root/arch/ia64/kernel/salinfo.c
blob: aa527d7e91f26bb12449ce978a58f0a2530c3f16 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
/*
 * salinfo.c
 *
 * Creates entries in /proc/sal for various system features.
 *
 * Copyright (c) 2003, 2006 Silicon Graphics, Inc.  All rights reserved.
 * Copyright (c) 2003 Hewlett-Packard Co
 *	Bjorn Helgaas <bjorn.helgaas@hp.com>
 *
 * 10/30/2001	jbarnes@sgi.com		copied much of Stephane's palinfo
 *					code to create this file
 * Oct 23 2003	kaos@sgi.com
 *   Replace IPI with set_cpus_allowed() to read a record from the required cpu.
 *   Redesign salinfo log processing to separate interrupt and user space
 *   contexts.
 *   Cache the record across multi-block reads from user space.
 *   Support > 64 cpus.
 *   Delete module_exit and MOD_INC/DEC_COUNT, salinfo cannot be a module.
 *
 * Jan 28 2004	kaos@sgi.com
 *   Periodically check for outstanding MCA or INIT records.
 *
 * Dec  5 2004	kaos@sgi.com
 *   Standardize which records are cleared automatically.
 *
 * Aug 18 2005	kaos@sgi.com
 *   mca.c may not pass a buffer, a NULL buffer just indicates that a new
 *   record is available in SAL.
 *   Replace some NR_CPUS by cpus_online, for hotplug cpu.
 *
 * Jan  5 2006        kaos@sgi.com
 *   Handle hotplug cpus coming online.
 *   Handle hotplug cpus going offline while they still have outstanding records.
 *   Use the cpu_* macros consistently.
 *   Replace the counting semaphore with a mutex and a test if the cpumask is non-empty.
 *   Modify the locking to make the test for "work to do" an atomic operation.
 */

#include <linux/capability.h>
#include <linux/cpu.h>
#include <linux/types.h>
#include <linux/proc_fs.h>
#include <linux/module.h>
#include <linux/smp.h>
#include <linux/timer.h>
#include <linux/vmalloc.h>
#include <linux/semaphore.h>

#include <asm/sal.h>
#include <asm/uaccess.h>

MODULE_AUTHOR("Jesse Barnes <jbarnes@sgi.com>");
MODULE_DESCRIPTION("/proc interface to IA-64 SAL features");
MODULE_LICENSE("GPL");

static int salinfo_read(char *page, char **start, off_t off, int count, int *eof, void *data);

typedef struct {
	const char		*name;		/* name of the proc entry */
	unsigned long           feature;        /* feature bit */
	struct proc_dir_entry	*entry;		/* registered entry (removal) */
} salinfo_entry_t;

/*
 * List {name,feature} pairs for every entry in /proc/sal/<feature>
 * that this module exports
 */
static salinfo_entry_t salinfo_entries[]={
	{ "bus_lock",           IA64_SAL_PLATFORM_FEATURE_BUS_LOCK, },
	{ "irq_redirection",	IA64_SAL_PLATFORM_FEATURE_IRQ_REDIR_HINT, },
	{ "ipi_redirection",	IA64_SAL_PLATFORM_FEATURE_IPI_REDIR_HINT, },
	{ "itc_drift",		IA64_SAL_PLATFORM_FEATURE_ITC_DRIFT, },
};

#define NR_SALINFO_ENTRIES ARRAY_SIZE(salinfo_entries)

static char *salinfo_log_name[] = {
	"mca",
	"init",
	"cmc",
	"cpe",
};

static struct proc_dir_entry *salinfo_proc_entries[
	ARRAY_SIZE(salinfo_entries) +			/* /proc/sal/bus_lock */
	ARRAY_SIZE(salinfo_log_name) +			/* /proc/sal/{mca,...} */
	(2 * ARRAY_SIZE(salinfo_log_name)) +		/* /proc/sal/mca/{event,data} */
	1];						/* /proc/sal */

/* Some records we get ourselves, some are accessed as saved data in buffers
 * that are owned by mca.c.
 */
struct salinfo_data_saved {
	u8*			buffer;
	u64			size;
	u64			id;
	int			cpu;
};

/* State transitions.  Actions are :-
 *   Write "read <cpunum>" to the data file.
 *   Write "clear <cpunum>" to the data file.
 *   Write "oemdata <cpunum> <offset> to the data file.
 *   Read from the data file.
 *   Close the data file.
 *
 * Start state is NO_DATA.
 *
 * NO_DATA
 *    write "read <cpunum>" -> NO_DATA or LOG_RECORD.
 *    write "clear <cpunum>" -> NO_DATA or LOG_RECORD.
 *    write "oemdata <cpunum> <offset> -> return -EINVAL.
 *    read data -> return EOF.
 *    close -> unchanged.  Free record areas.
 *
 * LOG_RECORD
 *    write "read <cpunum>" -> NO_DATA or LOG_RECORD.
 *    write "clear <cpunum>" -> NO_DATA or LOG_RECORD.
 *    write "oemdata <cpunum> <offset> -> format the oem data, goto OEMDATA.
 *    read data -> return the INIT/MCA/CMC/CPE record.
 *    close -> unchanged.  Keep record areas.
 *
 * OEMDATA
 *    write "read <cpunum>" -> NO_DATA or LOG_RECORD.
 *    write "clear <cpunum>" -> NO_DATA or LOG_RECORD.
 *    write "oemdata <cpunum> <offset> -> format the oem data, goto OEMDATA.
 *    read data -> return the formatted oemdata.
 *    close -> unchanged.  Keep record areas.
 *
 * Closing the data file does not change the state.  This allows shell scripts
 * to manipulate salinfo data, each shell redirection opens the file, does one
 * action then closes it again.  The record areas are only freed at close when
 * the state is NO_DATA.
 */
enum salinfo_state {
	STATE_NO_DATA,
	STATE_LOG_RECORD,
	STATE_OEMDATA,
};

struct salinfo_data {
	cpumask_t		cpu_event;	/* which cpus have outstanding events */
	struct semaphore	mutex;
	u8			*log_buffer;
	u64			log_size;
	u8			*oemdata;	/* decoded oem data */
	u64			oemdata_size;
	int			open;		/* single-open to prevent races */
	u8			type;
	u8			saved_num;	/* using a saved record? */
	enum salinfo_state	state :8;	/* processing state */
	u8			padding;
	int			cpu_check;	/* next CPU to check */
	struct salinfo_data_saved data_saved[5];/* save last 5 records from mca.c, must be < 255 */
};

static struct salinfo_data salinfo_data[ARRAY_SIZE(salinfo_log_name)];

static DEFINE_SPINLOCK(data_lock);
static DEFINE_SPINLOCK(data_saved_lock);

/** salinfo_platform_oemdata - optional callback to decode oemdata from an error
 * record.
 * @sect_header: pointer to the start of the section to decode.
 * @oemdata: returns vmalloc area containing the decoded output.
 * @oemdata_size: returns length of decoded output (strlen).
 *
 * Description: If user space asks for oem data to be decoded by the kernel
 * and/or prom and the platform has set salinfo_platform_oemdata to the address
 * of a platform specific routine then call that routine.  salinfo_platform_oemdata
 * vmalloc's and formats its output area, returning the address of the text
 * and its strlen.  Returns 0 for success, -ve for error.  The callback is
 * invoked on the cpu that generated the error record.
 */
int (*salinfo_platform_oemdata)(const u8 *sect_header, u8 **oemdata, u64 *oemdata_size);

struct salinfo_platform_oemdata_parms {
	const u8 *efi_guid;
	u8 **oemdata;
	u64 *oemdata_size;
	int ret;
};

/* Kick the mutex that tells user space that there is work to do.  Instead of
 * trying to track the state of the mutex across multiple cpus, in user
 * context, interrupt context, non-maskable interrupt context and hotplug cpu,
 * it is far easier just to grab the mutex if it is free then release it.
 *
 * This routine must be called with data_saved_lock held, to make the down/up
 * operation atomic.
 */
static void
salinfo_work_to_do(struct salinfo_data *data)
{
	(void)(down_trylock(&data->mutex) ?: 0);
	up(&data->mutex);
}

static void
salinfo_platform_oemdata_cpu(void *context)
{
	struct salinfo_platform_oemdata_parms *parms = context;
	parms->ret = salinfo_platform_oemdata(parms->efi_guid, parms->oemdata, parms->oemdata_size);
}

static void
shift1_data_saved (struct salinfo_data *data, int shift)
{
	memcpy(data->data_saved+shift, data->data_saved+shift+1,
	       (ARRAY_SIZE(data->data_saved) - (shift+1)) * sizeof(data->data_saved[0]));
	memset(data->data_saved + ARRAY_SIZE(data->data_saved) - 1, 0,
	       sizeof(data->data_saved[0]));
}

/* This routine is invoked in interrupt context.  Note: mca.c enables
 * interrupts before calling this code for CMC/CPE.  MCA and INIT events are
 * not irq safe, do not call any routines that use spinlocks, they may deadlock.
 * MCA and INIT records are recorded, a timer event will look for any
 * outstanding events and wake up the user space code.
 *
 * The buffer passed from mca.c points to the output from ia64_log_get. This is
 * a persistent buffer but its contents can change between the interrupt and
 * when user space processes the record.  Save the record id to identify
 * changes.  If the buffer is NULL then just update the bitmap.
 */
void
salinfo_log_wakeup(int type, u8 *buffer, u64 size, int irqsafe)
{
	struct salinfo_data *data = salinfo_data + type;
	struct salinfo_data_saved *data_saved;
	unsigned long flags = 0;
	int i;
	int saved_size = ARRAY_SIZE(data->data_saved);

	BUG_ON(type >= ARRAY_SIZE(salinfo_log_name));

	if (irqsafe)
		spin_lock_irqsave(&data_saved_lock, flags);
	if (buffer) {
		for (i = 0, data_saved = data->data_saved; i < saved_size; ++i, ++data_saved) {
			if (!data_saved->buffer)
				break;
		}
		if (i == saved_size) {
			if (!data->saved_num) {
				shift1_data_saved(data, 0);
				data_saved = data->data_saved + saved_size - 1;
			} else
				data_saved = NULL;
		}
		if (data_saved) {
			data_saved->cpu = smp_processor_id();
			data_saved->id = ((sal_log_record_header_t *)buffer)->id;
			data_saved->size = size;
			data_saved->buffer = buffer;
		}
	}
	cpu_set(smp_processor_id(), data->cpu_event);
	if (irqsafe) {
		salinfo_work_to_do(data);
		spin_unlock_irqrestore(&data_saved_lock, flags);
	}
}

/* Check for outstanding MCA/INIT records every minute (arbitrary) */
#define SALINFO_TIMER_DELAY (60*HZ)
static struct timer_list salinfo_timer;
extern void ia64_mlogbuf_dump(void);

static void
salinfo_timeout_check(struct salinfo_data *data)
{
	unsigned long flags;
	if (!data->open)
		return;
	if (!cpus_empty(data->cpu_event)) {
		spin_lock_irqsave(&data_saved_lock, flags);
		salinfo_work_to_do(data);
		spin_unlock_irqrestore(&data_saved_lock, flags);
	}
}

static void
salinfo_timeout (unsigned long arg)
{
	ia64_mlogbuf_dump();
	salinfo_timeout_check(salinfo_data + SAL_INFO_TYPE_MCA);
	salinfo_timeout_check(salinfo_data + SAL_INFO_TYPE_INIT);
	salinfo_timer.expires = jiffies + SALINFO_TIMER_DELAY;
	add_timer(&salinfo_timer);
}

static int
salinfo_event_open(struct inode *inode, struct file *file)
{
	if (!capable(CAP_SYS_ADMIN))
		return -EPERM;
	return 0;
}

static ssize_t
salinfo_event_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos)
{
	struct inode *inode = file_inode(file);
	struct proc_dir_entry *entry = PDE(inode);
	struct salinfo_data *data = entry->data;
	char cmd[32];
	size_t size;
	int i, n, cpu = -1;

retry:
	if (cpus_empty(data->cpu_event) && down_trylock(&data->mutex)) {
		if (file->f_flags & O_NONBLOCK)
			return -EAGAIN;
		if (down_interruptible(&data->mutex))
			return -EINTR;
	}

	n = data->cpu_check;
	for (i = 0; i < nr_cpu_ids; i++) {
		if (cpu_isset(n, data->cpu_event)) {
			if (!cpu_online(n)) {
				cpu_clear(n, data->cpu_event);
				continue;
			}
			cpu = n;
			break;
		}
		if (++n == nr_cpu_ids)
			n = 0;
	}

	if (cpu == -1)
		goto retry;

	ia64_mlogbuf_dump();

	/* for next read, start checking at next CPU */
	data->cpu_check = cpu;
	if (++data->cpu_check == nr_cpu_ids)
		data->cpu_check = 0;

	snprintf(cmd, sizeof(cmd), "read %d\n", cpu);

	size = strlen(cmd);
	if (size > count)
		size = count;
	if (copy_to_user(buffer, cmd, size))
		return -EFAULT;

	return size;
}

static const struct file_operations salinfo_event_fops = {
	.open  = salinfo_event_open,
	.read  = salinfo_event_read,
	.llseek = noop_llseek,
};

static int
salinfo_log_open(struct inode *inode, struct file *file)
{
	struct proc_dir_entry *entry = PDE(inode);
	struct salinfo_data *data = entry->data;

	if (!capable(CAP_SYS_ADMIN))
		return -EPERM;

	spin_lock(&data_lock);
	if (data->open) {
		spin_unlock(&data_lock);
		return -EBUSY;
	}
	data->open = 1;
	spin_unlock(&data_lock);

	if (data->state == STATE_NO_DATA &&
	    !(data->log_buffer = vmalloc(ia64_sal_get_state_info_size(data->type)))) {
		data->open = 0;
		return -ENOMEM;
	}

	return 0;
}

static int
salinfo_log_release(struct inode *inode, struct file *file)
{
	struct proc_dir_entry *entry = PDE(inode);
	struct salinfo_data *data = entry->data;

	if (data->state == STATE_NO_DATA) {
		vfree(data->log_buffer);
		vfree(data->oemdata);
		data->log_buffer = NULL;
		data->oemdata = NULL;
	}
	spin_lock(&data_lock);
	data->open = 0;
	spin_unlock(&data_lock);
	return 0;
}

static void
call_on_cpu(int cpu, void (*fn)(void *), void *arg)
{
	cpumask_t save_cpus_allowed = current->cpus_allowed;
	set_cpus_allowed_ptr(current, cpumask_of(cpu));
	(*fn)(arg);
	set_cpus_allowed_ptr(current, &save_cpus_allowed);
}

static void
salinfo_log_read_cpu(void *context)
{
	struct salinfo_data *data = context;
	sal_log_record_header_t *rh;
	data->log_size = ia64_sal_get_state_info(data->type, (u64 *) data->log_buffer);
	rh = (sal_log_record_header_t *)(data->log_buffer);
	/* Clear corrected errors as they are read from SAL */
	if (rh->severity == sal_log_severity_corrected)
		ia64_sal_clear_state_info(data->type);
}

static void
salinfo_log_new_read(int cpu, struct salinfo_data *data)
{
	struct salinfo_data_saved *data_saved;
	unsigned long flags;
	int i;
	int saved_size = ARRAY_SIZE(data->data_saved);

	data->saved_num = 0;
	spin_lock_irqsave(&data_saved_lock, flags);
retry:
	for (i = 0, data_saved = data->data_saved; i < saved_size; ++i, ++data_saved) {
		if (data_saved->buffer && data_saved->cpu == cpu) {
			sal_log_record_header_t *rh = (sal_log_record_header_t *)(data_saved->buffer);
			data->log_size = data_saved->size;
			memcpy(data->log_buffer, rh, data->log_size);
			barrier();	/* id check must not be moved */
			if (rh->id == data_saved->id) {
				data->saved_num = i+1;
				break;
			}
			/* saved record changed by mca.c since interrupt, discard it */
			shift1_data_saved(data, i);
			goto retry;
		}
	}
	spin_unlock_irqrestore(&data_saved_lock, flags);

	if (!data->saved_num)
		call_on_cpu(cpu, salinfo_log_read_cpu, data);
	if (!data->log_size) {
		data->state = STATE_NO_DATA;
		cpu_clear(cpu, data->cpu_event);
	} else {
		data->state = STATE_LOG_RECORD;
	}
}

static ssize_t
salinfo_log_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos)
{
	struct inode *inode = file_inode(file);
	struct proc_dir_entry *entry = PDE(inode);
	struct salinfo_data *data = entry->data;
	u8 *buf;
	u64 bufsize;

	if (data->state == STATE_LOG_RECORD) {
		buf = data->log_buffer;
		bufsize = data->log_size;
	} else if (data->state == STATE_OEMDATA) {
		buf = data->oemdata;
		bufsize = data->oemdata_size;
	} else {
		buf = NULL;
		bufsize = 0;
	}
	return simple_read_from_buffer(buffer, count, ppos, buf, bufsize);
}

static void
salinfo_log_clear_cpu(void *context)
{
	struct salinfo_data *data = context;
	ia64_sal_clear_state_info(data->type);
}

static int
salinfo_log_clear(struct salinfo_data *data, int cpu)
{
	sal_log_record_header_t *rh;
	unsigned long flags;
	spin_lock_irqsave(&data_saved_lock, flags);
	data->state = STATE_NO_DATA;
	if (!cpu_isset(cpu, data->cpu_event)) {
		spin_unlock_irqrestore(&data_saved_lock, flags);
		return 0;
	}
	cpu_clear(cpu, data->cpu_event);
	if (data->saved_num) {
		shift1_data_saved(data, data->saved_num - 1);
		data->saved_num = 0;
	}
	spin_unlock_irqrestore(&data_saved_lock, flags);
	rh = (sal_log_record_header_t *)(data->log_buffer);
	/* Corrected errors have already been cleared from SAL */
	if (rh->severity != sal_log_severity_corrected)
		call_on_cpu(cpu, salinfo_log_clear_cpu, data);
	/* clearing a record may make a new record visible */
	salinfo_log_new_read(cpu, data);
	if (data->state == STATE_LOG_RECORD) {
		spin_lock_irqsave(&data_saved_lock, flags);
		cpu_set(cpu, data->cpu_event);
		salinfo_work_to_do(data);
		spin_unlock_irqrestore(&data_saved_lock, flags);
	}
	return 0;
}

static ssize_t
salinfo_log_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
{
	struct inode *inode = file_inode(file);
	struct proc_dir_entry *entry = PDE(inode);
	struct salinfo_data *data = entry->data;
	char cmd[32];
	size_t size;
	u32 offset;
	int cpu;

	size = sizeof(cmd);
	if (count < size)
		size = count;
	if (copy_from_user(cmd, buffer, size))
		return -EFAULT;

	if (sscanf(cmd, "read %d", &cpu) == 1) {
		salinfo_log_new_read(cpu, data);
	} else if (sscanf(cmd, "clear %d", &cpu) == 1) {
		int ret;
		if ((ret = salinfo_log_clear(data, cpu)))
			count = ret;
	} else if (sscanf(cmd, "oemdata %d %d", &cpu, &offset) == 2) {
		if (data->state != STATE_LOG_RECORD && data->state != STATE_OEMDATA)
			return -EINVAL;
		if (offset > data->log_size - sizeof(efi_guid_t))
			return -EINVAL;
		data->state = STATE_OEMDATA;
		if (salinfo_platform_oemdata) {
			struct salinfo_platform_oemdata_parms parms = {
				.efi_guid = data->log_buffer + offset,
				.oemdata = &data->oemdata,
				.oemdata_size = &data->oemdata_size
			};
			call_on_cpu(cpu, salinfo_platform_oemdata_cpu, &parms);
			if (parms.ret)
				count = parms.ret;
		} else
			data->oemdata_size = 0;
	} else
		return -EINVAL;

	return count;
}

static const struct file_operations salinfo_data_fops = {
	.open    = salinfo_log_open,
	.release = salinfo_log_release,
	.read    = salinfo_log_read,
	.write   = salinfo_log_write,
	.llseek  = default_llseek,
};

static int __cpuinit
salinfo_cpu_callback(struct notifier_block *nb, unsigned long action, void *hcpu)
{
	unsigned int i, cpu = (unsigned long)hcpu;
	unsigned long flags;
	struct salinfo_data *data;
	switch (action) {
	case CPU_ONLINE:
	case CPU_ONLINE_FROZEN:
		spin_lock_irqsave(&data_saved_lock, flags);
		for (i = 0, data = salinfo_data;
		     i < ARRAY_SIZE(salinfo_data);
		     ++i, ++data) {
			cpu_set(cpu, data->cpu_event);
			salinfo_work_to_do(data);
		}
		spin_unlock_irqrestore(&data_saved_lock, flags);
		break;
	case CPU_DEAD:
	case CPU_DEAD_FROZEN:
		spin_lock_irqsave(&data_saved_lock, flags);
		for (i = 0, data = salinfo_data;
		     i < ARRAY_SIZE(salinfo_data);
		     ++i, ++data) {
			struct salinfo_data_saved *data_saved;
			int j;
			for (j = ARRAY_SIZE(data->data_saved) - 1, data_saved = data->data_saved + j;
			     j >= 0;
			     --j, --data_saved) {
				if (data_saved->buffer && data_saved->cpu == cpu) {
					shift1_data_saved(data, j);
				}
			}
			cpu_clear(cpu, data->cpu_event);
		}
		spin_unlock_irqrestore(&data_saved_lock, flags);
		break;
	}
	return NOTIFY_OK;
}

static struct notifier_block salinfo_cpu_notifier __cpuinitdata =
{
	.notifier_call = salinfo_cpu_callback,
	.priority = 0,
};

static int __init
salinfo_init(void)
{
	struct proc_dir_entry *salinfo_dir; /* /proc/sal dir entry */
	struct proc_dir_entry **sdir = salinfo_proc_entries; /* keeps track of every entry */
	struct proc_dir_entry *dir, *entry;
	struct salinfo_data *data;
	int i, j;

	salinfo_dir = proc_mkdir("sal", NULL);
	if (!salinfo_dir)
		return 0;

	for (i=0; i < NR_SALINFO_ENTRIES; i++) {
		/* pass the feature bit in question as misc data */
		*sdir++ = create_proc_read_entry (salinfo_entries[i].name, 0, salinfo_dir,
						  salinfo_read, (void *)salinfo_entries[i].feature);
	}

	for (i = 0; i < ARRAY_SIZE(salinfo_log_name); i++) {
		data = salinfo_data + i;
		data->type = i;
		sema_init(&data->mutex, 1);
		dir = proc_mkdir(salinfo_log_name[i], salinfo_dir);
		if (!dir)
			continue;

		entry = proc_create_data("event", S_IRUSR, dir,
					 &salinfo_event_fops, data);
		if (!entry)
			continue;
		*sdir++ = entry;

		entry = proc_create_data("data", S_IRUSR | S_IWUSR, dir,
					 &salinfo_data_fops, data);
		if (!entry)
			continue;
		*sdir++ = entry;

		/* we missed any events before now */
		for_each_online_cpu(j)
			cpu_set(j, data->cpu_event);

		*sdir++ = dir;
	}

	*sdir++ = salinfo_dir;

	init_timer(&salinfo_timer);
	salinfo_timer.expires = jiffies + SALINFO_TIMER_DELAY;
	salinfo_timer.function = &salinfo_timeout;
	add_timer(&salinfo_timer);

	register_hotcpu_notifier(&salinfo_cpu_notifier);

	return 0;
}

/*
 * 'data' contains an integer that corresponds to the feature we're
 * testing
 */
static int
salinfo_read(char *page, char **start, off_t off, int count, int *eof, void *data)
{
	int len = 0;

	len = sprintf(page, (sal_platform_features & (unsigned long)data) ? "1\n" : "0\n");

	if (len <= off+count) *eof = 1;

	*start = page + off;
	len   -= off;

	if (len>count) len = count;
	if (len<0) len = 0;

	return len;
}

module_init(salinfo_init);