xref: /openbmc/linux/drivers/acpi/apei/erst.c (revision 0da85d1e)
1 /*
2  * APEI Error Record Serialization Table support
3  *
4  * ERST is a way provided by APEI to save and retrieve hardware error
5  * information to and from a persistent store.
6  *
7  * For more information about ERST, please refer to ACPI Specification
8  * version 4.0, section 17.4.
9  *
10  * Copyright 2010 Intel Corp.
11  *   Author: Huang Ying <ying.huang@intel.com>
12  *
13  * This program is free software; you can redistribute it and/or
14  * modify it under the terms of the GNU General Public License version
15  * 2 as published by the Free Software Foundation.
16  *
17  * This program is distributed in the hope that it will be useful,
18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
20  * GNU General Public License for more details.
21  *
22  * You should have received a copy of the GNU General Public License
23  * along with this program; if not, write to the Free Software
24  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
25  */
26 
27 #include <linux/kernel.h>
28 #include <linux/module.h>
29 #include <linux/init.h>
30 #include <linux/delay.h>
31 #include <linux/io.h>
32 #include <linux/acpi.h>
33 #include <linux/uaccess.h>
34 #include <linux/cper.h>
35 #include <linux/nmi.h>
36 #include <linux/hardirq.h>
37 #include <linux/pstore.h>
38 #include <acpi/apei.h>
39 
40 #include "apei-internal.h"
41 
42 #undef pr_fmt
43 #define pr_fmt(fmt) "ERST: " fmt
44 
45 /* ERST command status */
46 #define ERST_STATUS_SUCCESS			0x0
47 #define ERST_STATUS_NOT_ENOUGH_SPACE		0x1
48 #define ERST_STATUS_HARDWARE_NOT_AVAILABLE	0x2
49 #define ERST_STATUS_FAILED			0x3
50 #define ERST_STATUS_RECORD_STORE_EMPTY		0x4
51 #define ERST_STATUS_RECORD_NOT_FOUND		0x5
52 
53 #define ERST_TAB_ENTRY(tab)						\
54 	((struct acpi_whea_header *)((char *)(tab) +			\
55 				     sizeof(struct acpi_table_erst)))
56 
57 #define SPIN_UNIT		100			/* 100ns */
58 /* Firmware should respond within 1 milliseconds */
59 #define FIRMWARE_TIMEOUT	(1 * NSEC_PER_MSEC)
60 #define FIRMWARE_MAX_STALL	50			/* 50us */
61 
62 int erst_disable;
63 EXPORT_SYMBOL_GPL(erst_disable);
64 
65 static struct acpi_table_erst *erst_tab;
66 
67 /* ERST Error Log Address Range atrributes */
68 #define ERST_RANGE_RESERVED	0x0001
69 #define ERST_RANGE_NVRAM	0x0002
70 #define ERST_RANGE_SLOW		0x0004
71 
72 /*
73  * ERST Error Log Address Range, used as buffer for reading/writing
74  * error records.
75  */
76 static struct erst_erange {
77 	u64 base;
78 	u64 size;
79 	void __iomem *vaddr;
80 	u32 attr;
81 } erst_erange;
82 
83 /*
84  * Prevent ERST interpreter to run simultaneously, because the
85  * corresponding firmware implementation may not work properly when
86  * invoked simultaneously.
87  *
88  * It is used to provide exclusive accessing for ERST Error Log
89  * Address Range too.
90  */
91 static DEFINE_RAW_SPINLOCK(erst_lock);
92 
93 static inline int erst_errno(int command_status)
94 {
95 	switch (command_status) {
96 	case ERST_STATUS_SUCCESS:
97 		return 0;
98 	case ERST_STATUS_HARDWARE_NOT_AVAILABLE:
99 		return -ENODEV;
100 	case ERST_STATUS_NOT_ENOUGH_SPACE:
101 		return -ENOSPC;
102 	case ERST_STATUS_RECORD_STORE_EMPTY:
103 	case ERST_STATUS_RECORD_NOT_FOUND:
104 		return -ENOENT;
105 	default:
106 		return -EINVAL;
107 	}
108 }
109 
110 static int erst_timedout(u64 *t, u64 spin_unit)
111 {
112 	if ((s64)*t < spin_unit) {
113 		pr_warn(FW_WARN "Firmware does not respond in time.\n");
114 		return 1;
115 	}
116 	*t -= spin_unit;
117 	ndelay(spin_unit);
118 	touch_nmi_watchdog();
119 	return 0;
120 }
121 
122 static int erst_exec_load_var1(struct apei_exec_context *ctx,
123 			       struct acpi_whea_header *entry)
124 {
125 	return __apei_exec_read_register(entry, &ctx->var1);
126 }
127 
128 static int erst_exec_load_var2(struct apei_exec_context *ctx,
129 			       struct acpi_whea_header *entry)
130 {
131 	return __apei_exec_read_register(entry, &ctx->var2);
132 }
133 
134 static int erst_exec_store_var1(struct apei_exec_context *ctx,
135 				struct acpi_whea_header *entry)
136 {
137 	return __apei_exec_write_register(entry, ctx->var1);
138 }
139 
140 static int erst_exec_add(struct apei_exec_context *ctx,
141 			 struct acpi_whea_header *entry)
142 {
143 	ctx->var1 += ctx->var2;
144 	return 0;
145 }
146 
147 static int erst_exec_subtract(struct apei_exec_context *ctx,
148 			      struct acpi_whea_header *entry)
149 {
150 	ctx->var1 -= ctx->var2;
151 	return 0;
152 }
153 
154 static int erst_exec_add_value(struct apei_exec_context *ctx,
155 			       struct acpi_whea_header *entry)
156 {
157 	int rc;
158 	u64 val;
159 
160 	rc = __apei_exec_read_register(entry, &val);
161 	if (rc)
162 		return rc;
163 	val += ctx->value;
164 	rc = __apei_exec_write_register(entry, val);
165 	return rc;
166 }
167 
168 static int erst_exec_subtract_value(struct apei_exec_context *ctx,
169 				    struct acpi_whea_header *entry)
170 {
171 	int rc;
172 	u64 val;
173 
174 	rc = __apei_exec_read_register(entry, &val);
175 	if (rc)
176 		return rc;
177 	val -= ctx->value;
178 	rc = __apei_exec_write_register(entry, val);
179 	return rc;
180 }
181 
182 static int erst_exec_stall(struct apei_exec_context *ctx,
183 			   struct acpi_whea_header *entry)
184 {
185 	u64 stall_time;
186 
187 	if (ctx->value > FIRMWARE_MAX_STALL) {
188 		if (!in_nmi())
189 			pr_warn(FW_WARN
190 			"Too long stall time for stall instruction: 0x%llx.\n",
191 				   ctx->value);
192 		stall_time = FIRMWARE_MAX_STALL;
193 	} else
194 		stall_time = ctx->value;
195 	udelay(stall_time);
196 	return 0;
197 }
198 
199 static int erst_exec_stall_while_true(struct apei_exec_context *ctx,
200 				      struct acpi_whea_header *entry)
201 {
202 	int rc;
203 	u64 val;
204 	u64 timeout = FIRMWARE_TIMEOUT;
205 	u64 stall_time;
206 
207 	if (ctx->var1 > FIRMWARE_MAX_STALL) {
208 		if (!in_nmi())
209 			pr_warn(FW_WARN
210 		"Too long stall time for stall while true instruction: 0x%llx.\n",
211 				   ctx->var1);
212 		stall_time = FIRMWARE_MAX_STALL;
213 	} else
214 		stall_time = ctx->var1;
215 
216 	for (;;) {
217 		rc = __apei_exec_read_register(entry, &val);
218 		if (rc)
219 			return rc;
220 		if (val != ctx->value)
221 			break;
222 		if (erst_timedout(&timeout, stall_time * NSEC_PER_USEC))
223 			return -EIO;
224 	}
225 	return 0;
226 }
227 
228 static int erst_exec_skip_next_instruction_if_true(
229 	struct apei_exec_context *ctx,
230 	struct acpi_whea_header *entry)
231 {
232 	int rc;
233 	u64 val;
234 
235 	rc = __apei_exec_read_register(entry, &val);
236 	if (rc)
237 		return rc;
238 	if (val == ctx->value) {
239 		ctx->ip += 2;
240 		return APEI_EXEC_SET_IP;
241 	}
242 
243 	return 0;
244 }
245 
246 static int erst_exec_goto(struct apei_exec_context *ctx,
247 			  struct acpi_whea_header *entry)
248 {
249 	ctx->ip = ctx->value;
250 	return APEI_EXEC_SET_IP;
251 }
252 
253 static int erst_exec_set_src_address_base(struct apei_exec_context *ctx,
254 					  struct acpi_whea_header *entry)
255 {
256 	return __apei_exec_read_register(entry, &ctx->src_base);
257 }
258 
259 static int erst_exec_set_dst_address_base(struct apei_exec_context *ctx,
260 					  struct acpi_whea_header *entry)
261 {
262 	return __apei_exec_read_register(entry, &ctx->dst_base);
263 }
264 
265 static int erst_exec_move_data(struct apei_exec_context *ctx,
266 			       struct acpi_whea_header *entry)
267 {
268 	int rc;
269 	u64 offset;
270 	void *src, *dst;
271 
272 	/* ioremap does not work in interrupt context */
273 	if (in_interrupt()) {
274 		pr_warn("MOVE_DATA can not be used in interrupt context.\n");
275 		return -EBUSY;
276 	}
277 
278 	rc = __apei_exec_read_register(entry, &offset);
279 	if (rc)
280 		return rc;
281 
282 	src = ioremap(ctx->src_base + offset, ctx->var2);
283 	if (!src)
284 		return -ENOMEM;
285 	dst = ioremap(ctx->dst_base + offset, ctx->var2);
286 	if (!dst) {
287 		iounmap(src);
288 		return -ENOMEM;
289 	}
290 
291 	memmove(dst, src, ctx->var2);
292 
293 	iounmap(src);
294 	iounmap(dst);
295 
296 	return 0;
297 }
298 
299 static struct apei_exec_ins_type erst_ins_type[] = {
300 	[ACPI_ERST_READ_REGISTER] = {
301 		.flags = APEI_EXEC_INS_ACCESS_REGISTER,
302 		.run = apei_exec_read_register,
303 	},
304 	[ACPI_ERST_READ_REGISTER_VALUE] = {
305 		.flags = APEI_EXEC_INS_ACCESS_REGISTER,
306 		.run = apei_exec_read_register_value,
307 	},
308 	[ACPI_ERST_WRITE_REGISTER] = {
309 		.flags = APEI_EXEC_INS_ACCESS_REGISTER,
310 		.run = apei_exec_write_register,
311 	},
312 	[ACPI_ERST_WRITE_REGISTER_VALUE] = {
313 		.flags = APEI_EXEC_INS_ACCESS_REGISTER,
314 		.run = apei_exec_write_register_value,
315 	},
316 	[ACPI_ERST_NOOP] = {
317 		.flags = 0,
318 		.run = apei_exec_noop,
319 	},
320 	[ACPI_ERST_LOAD_VAR1] = {
321 		.flags = APEI_EXEC_INS_ACCESS_REGISTER,
322 		.run = erst_exec_load_var1,
323 	},
324 	[ACPI_ERST_LOAD_VAR2] = {
325 		.flags = APEI_EXEC_INS_ACCESS_REGISTER,
326 		.run = erst_exec_load_var2,
327 	},
328 	[ACPI_ERST_STORE_VAR1] = {
329 		.flags = APEI_EXEC_INS_ACCESS_REGISTER,
330 		.run = erst_exec_store_var1,
331 	},
332 	[ACPI_ERST_ADD] = {
333 		.flags = 0,
334 		.run = erst_exec_add,
335 	},
336 	[ACPI_ERST_SUBTRACT] = {
337 		.flags = 0,
338 		.run = erst_exec_subtract,
339 	},
340 	[ACPI_ERST_ADD_VALUE] = {
341 		.flags = APEI_EXEC_INS_ACCESS_REGISTER,
342 		.run = erst_exec_add_value,
343 	},
344 	[ACPI_ERST_SUBTRACT_VALUE] = {
345 		.flags = APEI_EXEC_INS_ACCESS_REGISTER,
346 		.run = erst_exec_subtract_value,
347 	},
348 	[ACPI_ERST_STALL] = {
349 		.flags = 0,
350 		.run = erst_exec_stall,
351 	},
352 	[ACPI_ERST_STALL_WHILE_TRUE] = {
353 		.flags = APEI_EXEC_INS_ACCESS_REGISTER,
354 		.run = erst_exec_stall_while_true,
355 	},
356 	[ACPI_ERST_SKIP_NEXT_IF_TRUE] = {
357 		.flags = APEI_EXEC_INS_ACCESS_REGISTER,
358 		.run = erst_exec_skip_next_instruction_if_true,
359 	},
360 	[ACPI_ERST_GOTO] = {
361 		.flags = 0,
362 		.run = erst_exec_goto,
363 	},
364 	[ACPI_ERST_SET_SRC_ADDRESS_BASE] = {
365 		.flags = APEI_EXEC_INS_ACCESS_REGISTER,
366 		.run = erst_exec_set_src_address_base,
367 	},
368 	[ACPI_ERST_SET_DST_ADDRESS_BASE] = {
369 		.flags = APEI_EXEC_INS_ACCESS_REGISTER,
370 		.run = erst_exec_set_dst_address_base,
371 	},
372 	[ACPI_ERST_MOVE_DATA] = {
373 		.flags = APEI_EXEC_INS_ACCESS_REGISTER,
374 		.run = erst_exec_move_data,
375 	},
376 };
377 
378 static inline void erst_exec_ctx_init(struct apei_exec_context *ctx)
379 {
380 	apei_exec_ctx_init(ctx, erst_ins_type, ARRAY_SIZE(erst_ins_type),
381 			   ERST_TAB_ENTRY(erst_tab), erst_tab->entries);
382 }
383 
384 static int erst_get_erange(struct erst_erange *range)
385 {
386 	struct apei_exec_context ctx;
387 	int rc;
388 
389 	erst_exec_ctx_init(&ctx);
390 	rc = apei_exec_run(&ctx, ACPI_ERST_GET_ERROR_RANGE);
391 	if (rc)
392 		return rc;
393 	range->base = apei_exec_ctx_get_output(&ctx);
394 	rc = apei_exec_run(&ctx, ACPI_ERST_GET_ERROR_LENGTH);
395 	if (rc)
396 		return rc;
397 	range->size = apei_exec_ctx_get_output(&ctx);
398 	rc = apei_exec_run(&ctx, ACPI_ERST_GET_ERROR_ATTRIBUTES);
399 	if (rc)
400 		return rc;
401 	range->attr = apei_exec_ctx_get_output(&ctx);
402 
403 	return 0;
404 }
405 
406 static ssize_t __erst_get_record_count(void)
407 {
408 	struct apei_exec_context ctx;
409 	int rc;
410 
411 	erst_exec_ctx_init(&ctx);
412 	rc = apei_exec_run(&ctx, ACPI_ERST_GET_RECORD_COUNT);
413 	if (rc)
414 		return rc;
415 	return apei_exec_ctx_get_output(&ctx);
416 }
417 
418 ssize_t erst_get_record_count(void)
419 {
420 	ssize_t count;
421 	unsigned long flags;
422 
423 	if (erst_disable)
424 		return -ENODEV;
425 
426 	raw_spin_lock_irqsave(&erst_lock, flags);
427 	count = __erst_get_record_count();
428 	raw_spin_unlock_irqrestore(&erst_lock, flags);
429 
430 	return count;
431 }
432 EXPORT_SYMBOL_GPL(erst_get_record_count);
433 
434 #define ERST_RECORD_ID_CACHE_SIZE_MIN	16
435 #define ERST_RECORD_ID_CACHE_SIZE_MAX	1024
436 
437 struct erst_record_id_cache {
438 	struct mutex lock;
439 	u64 *entries;
440 	int len;
441 	int size;
442 	int refcount;
443 };
444 
445 static struct erst_record_id_cache erst_record_id_cache = {
446 	.lock = __MUTEX_INITIALIZER(erst_record_id_cache.lock),
447 	.refcount = 0,
448 };
449 
450 static int __erst_get_next_record_id(u64 *record_id)
451 {
452 	struct apei_exec_context ctx;
453 	int rc;
454 
455 	erst_exec_ctx_init(&ctx);
456 	rc = apei_exec_run(&ctx, ACPI_ERST_GET_RECORD_ID);
457 	if (rc)
458 		return rc;
459 	*record_id = apei_exec_ctx_get_output(&ctx);
460 
461 	return 0;
462 }
463 
464 int erst_get_record_id_begin(int *pos)
465 {
466 	int rc;
467 
468 	if (erst_disable)
469 		return -ENODEV;
470 
471 	rc = mutex_lock_interruptible(&erst_record_id_cache.lock);
472 	if (rc)
473 		return rc;
474 	erst_record_id_cache.refcount++;
475 	mutex_unlock(&erst_record_id_cache.lock);
476 
477 	*pos = 0;
478 
479 	return 0;
480 }
481 EXPORT_SYMBOL_GPL(erst_get_record_id_begin);
482 
483 /* erst_record_id_cache.lock must be held by caller */
484 static int __erst_record_id_cache_add_one(void)
485 {
486 	u64 id, prev_id, first_id;
487 	int i, rc;
488 	u64 *entries;
489 	unsigned long flags;
490 
491 	id = prev_id = first_id = APEI_ERST_INVALID_RECORD_ID;
492 retry:
493 	raw_spin_lock_irqsave(&erst_lock, flags);
494 	rc = __erst_get_next_record_id(&id);
495 	raw_spin_unlock_irqrestore(&erst_lock, flags);
496 	if (rc == -ENOENT)
497 		return 0;
498 	if (rc)
499 		return rc;
500 	if (id == APEI_ERST_INVALID_RECORD_ID)
501 		return 0;
502 	/* can not skip current ID, or loop back to first ID */
503 	if (id == prev_id || id == first_id)
504 		return 0;
505 	if (first_id == APEI_ERST_INVALID_RECORD_ID)
506 		first_id = id;
507 	prev_id = id;
508 
509 	entries = erst_record_id_cache.entries;
510 	for (i = 0; i < erst_record_id_cache.len; i++) {
511 		if (entries[i] == id)
512 			break;
513 	}
514 	/* record id already in cache, try next */
515 	if (i < erst_record_id_cache.len)
516 		goto retry;
517 	if (erst_record_id_cache.len >= erst_record_id_cache.size) {
518 		int new_size, alloc_size;
519 		u64 *new_entries;
520 
521 		new_size = erst_record_id_cache.size * 2;
522 		new_size = clamp_val(new_size, ERST_RECORD_ID_CACHE_SIZE_MIN,
523 				     ERST_RECORD_ID_CACHE_SIZE_MAX);
524 		if (new_size <= erst_record_id_cache.size) {
525 			if (printk_ratelimit())
526 				pr_warn(FW_WARN "too many record IDs!\n");
527 			return 0;
528 		}
529 		alloc_size = new_size * sizeof(entries[0]);
530 		if (alloc_size < PAGE_SIZE)
531 			new_entries = kmalloc(alloc_size, GFP_KERNEL);
532 		else
533 			new_entries = vmalloc(alloc_size);
534 		if (!new_entries)
535 			return -ENOMEM;
536 		memcpy(new_entries, entries,
537 		       erst_record_id_cache.len * sizeof(entries[0]));
538 		if (erst_record_id_cache.size < PAGE_SIZE)
539 			kfree(entries);
540 		else
541 			vfree(entries);
542 		erst_record_id_cache.entries = entries = new_entries;
543 		erst_record_id_cache.size = new_size;
544 	}
545 	entries[i] = id;
546 	erst_record_id_cache.len++;
547 
548 	return 1;
549 }
550 
551 /*
552  * Get the record ID of an existing error record on the persistent
553  * storage. If there is no error record on the persistent storage, the
554  * returned record_id is APEI_ERST_INVALID_RECORD_ID.
555  */
556 int erst_get_record_id_next(int *pos, u64 *record_id)
557 {
558 	int rc = 0;
559 	u64 *entries;
560 
561 	if (erst_disable)
562 		return -ENODEV;
563 
564 	/* must be enclosed by erst_get_record_id_begin/end */
565 	BUG_ON(!erst_record_id_cache.refcount);
566 	BUG_ON(*pos < 0 || *pos > erst_record_id_cache.len);
567 
568 	mutex_lock(&erst_record_id_cache.lock);
569 	entries = erst_record_id_cache.entries;
570 	for (; *pos < erst_record_id_cache.len; (*pos)++)
571 		if (entries[*pos] != APEI_ERST_INVALID_RECORD_ID)
572 			break;
573 	/* found next record id in cache */
574 	if (*pos < erst_record_id_cache.len) {
575 		*record_id = entries[*pos];
576 		(*pos)++;
577 		goto out_unlock;
578 	}
579 
580 	/* Try to add one more record ID to cache */
581 	rc = __erst_record_id_cache_add_one();
582 	if (rc < 0)
583 		goto out_unlock;
584 	/* successfully add one new ID */
585 	if (rc == 1) {
586 		*record_id = erst_record_id_cache.entries[*pos];
587 		(*pos)++;
588 		rc = 0;
589 	} else {
590 		*pos = -1;
591 		*record_id = APEI_ERST_INVALID_RECORD_ID;
592 	}
593 out_unlock:
594 	mutex_unlock(&erst_record_id_cache.lock);
595 
596 	return rc;
597 }
598 EXPORT_SYMBOL_GPL(erst_get_record_id_next);
599 
600 /* erst_record_id_cache.lock must be held by caller */
601 static void __erst_record_id_cache_compact(void)
602 {
603 	int i, wpos = 0;
604 	u64 *entries;
605 
606 	if (erst_record_id_cache.refcount)
607 		return;
608 
609 	entries = erst_record_id_cache.entries;
610 	for (i = 0; i < erst_record_id_cache.len; i++) {
611 		if (entries[i] == APEI_ERST_INVALID_RECORD_ID)
612 			continue;
613 		if (wpos != i)
614 			entries[wpos] = entries[i];
615 		wpos++;
616 	}
617 	erst_record_id_cache.len = wpos;
618 }
619 
620 void erst_get_record_id_end(void)
621 {
622 	/*
623 	 * erst_disable != 0 should be detected by invoker via the
624 	 * return value of erst_get_record_id_begin/next, so this
625 	 * function should not be called for erst_disable != 0.
626 	 */
627 	BUG_ON(erst_disable);
628 
629 	mutex_lock(&erst_record_id_cache.lock);
630 	erst_record_id_cache.refcount--;
631 	BUG_ON(erst_record_id_cache.refcount < 0);
632 	__erst_record_id_cache_compact();
633 	mutex_unlock(&erst_record_id_cache.lock);
634 }
635 EXPORT_SYMBOL_GPL(erst_get_record_id_end);
636 
637 static int __erst_write_to_storage(u64 offset)
638 {
639 	struct apei_exec_context ctx;
640 	u64 timeout = FIRMWARE_TIMEOUT;
641 	u64 val;
642 	int rc;
643 
644 	erst_exec_ctx_init(&ctx);
645 	rc = apei_exec_run_optional(&ctx, ACPI_ERST_BEGIN_WRITE);
646 	if (rc)
647 		return rc;
648 	apei_exec_ctx_set_input(&ctx, offset);
649 	rc = apei_exec_run(&ctx, ACPI_ERST_SET_RECORD_OFFSET);
650 	if (rc)
651 		return rc;
652 	rc = apei_exec_run(&ctx, ACPI_ERST_EXECUTE_OPERATION);
653 	if (rc)
654 		return rc;
655 	for (;;) {
656 		rc = apei_exec_run(&ctx, ACPI_ERST_CHECK_BUSY_STATUS);
657 		if (rc)
658 			return rc;
659 		val = apei_exec_ctx_get_output(&ctx);
660 		if (!val)
661 			break;
662 		if (erst_timedout(&timeout, SPIN_UNIT))
663 			return -EIO;
664 	}
665 	rc = apei_exec_run(&ctx, ACPI_ERST_GET_COMMAND_STATUS);
666 	if (rc)
667 		return rc;
668 	val = apei_exec_ctx_get_output(&ctx);
669 	rc = apei_exec_run_optional(&ctx, ACPI_ERST_END);
670 	if (rc)
671 		return rc;
672 
673 	return erst_errno(val);
674 }
675 
676 static int __erst_read_from_storage(u64 record_id, u64 offset)
677 {
678 	struct apei_exec_context ctx;
679 	u64 timeout = FIRMWARE_TIMEOUT;
680 	u64 val;
681 	int rc;
682 
683 	erst_exec_ctx_init(&ctx);
684 	rc = apei_exec_run_optional(&ctx, ACPI_ERST_BEGIN_READ);
685 	if (rc)
686 		return rc;
687 	apei_exec_ctx_set_input(&ctx, offset);
688 	rc = apei_exec_run(&ctx, ACPI_ERST_SET_RECORD_OFFSET);
689 	if (rc)
690 		return rc;
691 	apei_exec_ctx_set_input(&ctx, record_id);
692 	rc = apei_exec_run(&ctx, ACPI_ERST_SET_RECORD_ID);
693 	if (rc)
694 		return rc;
695 	rc = apei_exec_run(&ctx, ACPI_ERST_EXECUTE_OPERATION);
696 	if (rc)
697 		return rc;
698 	for (;;) {
699 		rc = apei_exec_run(&ctx, ACPI_ERST_CHECK_BUSY_STATUS);
700 		if (rc)
701 			return rc;
702 		val = apei_exec_ctx_get_output(&ctx);
703 		if (!val)
704 			break;
705 		if (erst_timedout(&timeout, SPIN_UNIT))
706 			return -EIO;
707 	};
708 	rc = apei_exec_run(&ctx, ACPI_ERST_GET_COMMAND_STATUS);
709 	if (rc)
710 		return rc;
711 	val = apei_exec_ctx_get_output(&ctx);
712 	rc = apei_exec_run_optional(&ctx, ACPI_ERST_END);
713 	if (rc)
714 		return rc;
715 
716 	return erst_errno(val);
717 }
718 
719 static int __erst_clear_from_storage(u64 record_id)
720 {
721 	struct apei_exec_context ctx;
722 	u64 timeout = FIRMWARE_TIMEOUT;
723 	u64 val;
724 	int rc;
725 
726 	erst_exec_ctx_init(&ctx);
727 	rc = apei_exec_run_optional(&ctx, ACPI_ERST_BEGIN_CLEAR);
728 	if (rc)
729 		return rc;
730 	apei_exec_ctx_set_input(&ctx, record_id);
731 	rc = apei_exec_run(&ctx, ACPI_ERST_SET_RECORD_ID);
732 	if (rc)
733 		return rc;
734 	rc = apei_exec_run(&ctx, ACPI_ERST_EXECUTE_OPERATION);
735 	if (rc)
736 		return rc;
737 	for (;;) {
738 		rc = apei_exec_run(&ctx, ACPI_ERST_CHECK_BUSY_STATUS);
739 		if (rc)
740 			return rc;
741 		val = apei_exec_ctx_get_output(&ctx);
742 		if (!val)
743 			break;
744 		if (erst_timedout(&timeout, SPIN_UNIT))
745 			return -EIO;
746 	}
747 	rc = apei_exec_run(&ctx, ACPI_ERST_GET_COMMAND_STATUS);
748 	if (rc)
749 		return rc;
750 	val = apei_exec_ctx_get_output(&ctx);
751 	rc = apei_exec_run_optional(&ctx, ACPI_ERST_END);
752 	if (rc)
753 		return rc;
754 
755 	return erst_errno(val);
756 }
757 
758 /* NVRAM ERST Error Log Address Range is not supported yet */
759 static void pr_unimpl_nvram(void)
760 {
761 	if (printk_ratelimit())
762 		pr_warn("NVRAM ERST Log Address Range not implemented yet.\n");
763 }
764 
765 static int __erst_write_to_nvram(const struct cper_record_header *record)
766 {
767 	/* do not print message, because printk is not safe for NMI */
768 	return -ENOSYS;
769 }
770 
771 static int __erst_read_to_erange_from_nvram(u64 record_id, u64 *offset)
772 {
773 	pr_unimpl_nvram();
774 	return -ENOSYS;
775 }
776 
777 static int __erst_clear_from_nvram(u64 record_id)
778 {
779 	pr_unimpl_nvram();
780 	return -ENOSYS;
781 }
782 
783 int erst_write(const struct cper_record_header *record)
784 {
785 	int rc;
786 	unsigned long flags;
787 	struct cper_record_header *rcd_erange;
788 
789 	if (erst_disable)
790 		return -ENODEV;
791 
792 	if (memcmp(record->signature, CPER_SIG_RECORD, CPER_SIG_SIZE))
793 		return -EINVAL;
794 
795 	if (erst_erange.attr & ERST_RANGE_NVRAM) {
796 		if (!raw_spin_trylock_irqsave(&erst_lock, flags))
797 			return -EBUSY;
798 		rc = __erst_write_to_nvram(record);
799 		raw_spin_unlock_irqrestore(&erst_lock, flags);
800 		return rc;
801 	}
802 
803 	if (record->record_length > erst_erange.size)
804 		return -EINVAL;
805 
806 	if (!raw_spin_trylock_irqsave(&erst_lock, flags))
807 		return -EBUSY;
808 	memcpy(erst_erange.vaddr, record, record->record_length);
809 	rcd_erange = erst_erange.vaddr;
810 	/* signature for serialization system */
811 	memcpy(&rcd_erange->persistence_information, "ER", 2);
812 
813 	rc = __erst_write_to_storage(0);
814 	raw_spin_unlock_irqrestore(&erst_lock, flags);
815 
816 	return rc;
817 }
818 EXPORT_SYMBOL_GPL(erst_write);
819 
820 static int __erst_read_to_erange(u64 record_id, u64 *offset)
821 {
822 	int rc;
823 
824 	if (erst_erange.attr & ERST_RANGE_NVRAM)
825 		return __erst_read_to_erange_from_nvram(
826 			record_id, offset);
827 
828 	rc = __erst_read_from_storage(record_id, 0);
829 	if (rc)
830 		return rc;
831 	*offset = 0;
832 
833 	return 0;
834 }
835 
836 static ssize_t __erst_read(u64 record_id, struct cper_record_header *record,
837 			   size_t buflen)
838 {
839 	int rc;
840 	u64 offset, len = 0;
841 	struct cper_record_header *rcd_tmp;
842 
843 	rc = __erst_read_to_erange(record_id, &offset);
844 	if (rc)
845 		return rc;
846 	rcd_tmp = erst_erange.vaddr + offset;
847 	len = rcd_tmp->record_length;
848 	if (len <= buflen)
849 		memcpy(record, rcd_tmp, len);
850 
851 	return len;
852 }
853 
854 /*
855  * If return value > buflen, the buffer size is not big enough,
856  * else if return value < 0, something goes wrong,
857  * else everything is OK, and return value is record length
858  */
859 ssize_t erst_read(u64 record_id, struct cper_record_header *record,
860 		  size_t buflen)
861 {
862 	ssize_t len;
863 	unsigned long flags;
864 
865 	if (erst_disable)
866 		return -ENODEV;
867 
868 	raw_spin_lock_irqsave(&erst_lock, flags);
869 	len = __erst_read(record_id, record, buflen);
870 	raw_spin_unlock_irqrestore(&erst_lock, flags);
871 	return len;
872 }
873 EXPORT_SYMBOL_GPL(erst_read);
874 
875 int erst_clear(u64 record_id)
876 {
877 	int rc, i;
878 	unsigned long flags;
879 	u64 *entries;
880 
881 	if (erst_disable)
882 		return -ENODEV;
883 
884 	rc = mutex_lock_interruptible(&erst_record_id_cache.lock);
885 	if (rc)
886 		return rc;
887 	raw_spin_lock_irqsave(&erst_lock, flags);
888 	if (erst_erange.attr & ERST_RANGE_NVRAM)
889 		rc = __erst_clear_from_nvram(record_id);
890 	else
891 		rc = __erst_clear_from_storage(record_id);
892 	raw_spin_unlock_irqrestore(&erst_lock, flags);
893 	if (rc)
894 		goto out;
895 	entries = erst_record_id_cache.entries;
896 	for (i = 0; i < erst_record_id_cache.len; i++) {
897 		if (entries[i] == record_id)
898 			entries[i] = APEI_ERST_INVALID_RECORD_ID;
899 	}
900 	__erst_record_id_cache_compact();
901 out:
902 	mutex_unlock(&erst_record_id_cache.lock);
903 	return rc;
904 }
905 EXPORT_SYMBOL_GPL(erst_clear);
906 
907 static int __init setup_erst_disable(char *str)
908 {
909 	erst_disable = 1;
910 	return 0;
911 }
912 
913 __setup("erst_disable", setup_erst_disable);
914 
915 static int erst_check_table(struct acpi_table_erst *erst_tab)
916 {
917 	if ((erst_tab->header_length !=
918 	     (sizeof(struct acpi_table_erst) - sizeof(erst_tab->header)))
919 	    && (erst_tab->header_length != sizeof(struct acpi_table_erst)))
920 		return -EINVAL;
921 	if (erst_tab->header.length < sizeof(struct acpi_table_erst))
922 		return -EINVAL;
923 	if (erst_tab->entries !=
924 	    (erst_tab->header.length - sizeof(struct acpi_table_erst)) /
925 	    sizeof(struct acpi_erst_entry))
926 		return -EINVAL;
927 
928 	return 0;
929 }
930 
931 static int erst_open_pstore(struct pstore_info *psi);
932 static int erst_close_pstore(struct pstore_info *psi);
933 static ssize_t erst_reader(u64 *id, enum pstore_type_id *type, int *count,
934 			   struct timespec *time, char **buf,
935 			   bool *compressed, struct pstore_info *psi);
936 static int erst_writer(enum pstore_type_id type, enum kmsg_dump_reason reason,
937 		       u64 *id, unsigned int part, int count, bool compressed,
938 		       size_t size, struct pstore_info *psi);
939 static int erst_clearer(enum pstore_type_id type, u64 id, int count,
940 			struct timespec time, struct pstore_info *psi);
941 
942 static struct pstore_info erst_info = {
943 	.owner		= THIS_MODULE,
944 	.name		= "erst",
945 	.flags		= PSTORE_FLAGS_FRAGILE,
946 	.open		= erst_open_pstore,
947 	.close		= erst_close_pstore,
948 	.read		= erst_reader,
949 	.write		= erst_writer,
950 	.erase		= erst_clearer
951 };
952 
953 #define CPER_CREATOR_PSTORE						\
954 	UUID_LE(0x75a574e3, 0x5052, 0x4b29, 0x8a, 0x8e, 0xbe, 0x2c,	\
955 		0x64, 0x90, 0xb8, 0x9d)
956 #define CPER_SECTION_TYPE_DMESG						\
957 	UUID_LE(0xc197e04e, 0xd545, 0x4a70, 0x9c, 0x17, 0xa5, 0x54,	\
958 		0x94, 0x19, 0xeb, 0x12)
959 #define CPER_SECTION_TYPE_DMESG_Z					\
960 	UUID_LE(0x4f118707, 0x04dd, 0x4055, 0xb5, 0xdd, 0x95, 0x6d,	\
961 		0x34, 0xdd, 0xfa, 0xc6)
962 #define CPER_SECTION_TYPE_MCE						\
963 	UUID_LE(0xfe08ffbe, 0x95e4, 0x4be7, 0xbc, 0x73, 0x40, 0x96,	\
964 		0x04, 0x4a, 0x38, 0xfc)
965 
966 struct cper_pstore_record {
967 	struct cper_record_header hdr;
968 	struct cper_section_descriptor sec_hdr;
969 	char data[];
970 } __packed;
971 
972 static int reader_pos;
973 
974 static int erst_open_pstore(struct pstore_info *psi)
975 {
976 	int rc;
977 
978 	if (erst_disable)
979 		return -ENODEV;
980 
981 	rc = erst_get_record_id_begin(&reader_pos);
982 
983 	return rc;
984 }
985 
986 static int erst_close_pstore(struct pstore_info *psi)
987 {
988 	erst_get_record_id_end();
989 
990 	return 0;
991 }
992 
993 static ssize_t erst_reader(u64 *id, enum pstore_type_id *type, int *count,
994 			   struct timespec *time, char **buf,
995 			   bool *compressed, struct pstore_info *psi)
996 {
997 	int rc;
998 	ssize_t len = 0;
999 	u64 record_id;
1000 	struct cper_pstore_record *rcd;
1001 	size_t rcd_len = sizeof(*rcd) + erst_info.bufsize;
1002 
1003 	if (erst_disable)
1004 		return -ENODEV;
1005 
1006 	rcd = kmalloc(rcd_len, GFP_KERNEL);
1007 	if (!rcd) {
1008 		rc = -ENOMEM;
1009 		goto out;
1010 	}
1011 skip:
1012 	rc = erst_get_record_id_next(&reader_pos, &record_id);
1013 	if (rc)
1014 		goto out;
1015 
1016 	/* no more record */
1017 	if (record_id == APEI_ERST_INVALID_RECORD_ID) {
1018 		rc = -EINVAL;
1019 		goto out;
1020 	}
1021 
1022 	len = erst_read(record_id, &rcd->hdr, rcd_len);
1023 	/* The record may be cleared by others, try read next record */
1024 	if (len == -ENOENT)
1025 		goto skip;
1026 	else if (len < sizeof(*rcd)) {
1027 		rc = -EIO;
1028 		goto out;
1029 	}
1030 	if (uuid_le_cmp(rcd->hdr.creator_id, CPER_CREATOR_PSTORE) != 0)
1031 		goto skip;
1032 
1033 	*buf = kmalloc(len, GFP_KERNEL);
1034 	if (*buf == NULL) {
1035 		rc = -ENOMEM;
1036 		goto out;
1037 	}
1038 	memcpy(*buf, rcd->data, len - sizeof(*rcd));
1039 	*id = record_id;
1040 	*compressed = false;
1041 	if (uuid_le_cmp(rcd->sec_hdr.section_type,
1042 			CPER_SECTION_TYPE_DMESG_Z) == 0) {
1043 		*type = PSTORE_TYPE_DMESG;
1044 		*compressed = true;
1045 	} else if (uuid_le_cmp(rcd->sec_hdr.section_type,
1046 			CPER_SECTION_TYPE_DMESG) == 0)
1047 		*type = PSTORE_TYPE_DMESG;
1048 	else if (uuid_le_cmp(rcd->sec_hdr.section_type,
1049 			     CPER_SECTION_TYPE_MCE) == 0)
1050 		*type = PSTORE_TYPE_MCE;
1051 	else
1052 		*type = PSTORE_TYPE_UNKNOWN;
1053 
1054 	if (rcd->hdr.validation_bits & CPER_VALID_TIMESTAMP)
1055 		time->tv_sec = rcd->hdr.timestamp;
1056 	else
1057 		time->tv_sec = 0;
1058 	time->tv_nsec = 0;
1059 
1060 out:
1061 	kfree(rcd);
1062 	return (rc < 0) ? rc : (len - sizeof(*rcd));
1063 }
1064 
1065 static int erst_writer(enum pstore_type_id type, enum kmsg_dump_reason reason,
1066 		       u64 *id, unsigned int part, int count, bool compressed,
1067 		       size_t size, struct pstore_info *psi)
1068 {
1069 	struct cper_pstore_record *rcd = (struct cper_pstore_record *)
1070 					(erst_info.buf - sizeof(*rcd));
1071 	int ret;
1072 
1073 	memset(rcd, 0, sizeof(*rcd));
1074 	memcpy(rcd->hdr.signature, CPER_SIG_RECORD, CPER_SIG_SIZE);
1075 	rcd->hdr.revision = CPER_RECORD_REV;
1076 	rcd->hdr.signature_end = CPER_SIG_END;
1077 	rcd->hdr.section_count = 1;
1078 	rcd->hdr.error_severity = CPER_SEV_FATAL;
1079 	/* timestamp valid. platform_id, partition_id are invalid */
1080 	rcd->hdr.validation_bits = CPER_VALID_TIMESTAMP;
1081 	rcd->hdr.timestamp = get_seconds();
1082 	rcd->hdr.record_length = sizeof(*rcd) + size;
1083 	rcd->hdr.creator_id = CPER_CREATOR_PSTORE;
1084 	rcd->hdr.notification_type = CPER_NOTIFY_MCE;
1085 	rcd->hdr.record_id = cper_next_record_id();
1086 	rcd->hdr.flags = CPER_HW_ERROR_FLAGS_PREVERR;
1087 
1088 	rcd->sec_hdr.section_offset = sizeof(*rcd);
1089 	rcd->sec_hdr.section_length = size;
1090 	rcd->sec_hdr.revision = CPER_SEC_REV;
1091 	/* fru_id and fru_text is invalid */
1092 	rcd->sec_hdr.validation_bits = 0;
1093 	rcd->sec_hdr.flags = CPER_SEC_PRIMARY;
1094 	switch (type) {
1095 	case PSTORE_TYPE_DMESG:
1096 		if (compressed)
1097 			rcd->sec_hdr.section_type = CPER_SECTION_TYPE_DMESG_Z;
1098 		else
1099 			rcd->sec_hdr.section_type = CPER_SECTION_TYPE_DMESG;
1100 		break;
1101 	case PSTORE_TYPE_MCE:
1102 		rcd->sec_hdr.section_type = CPER_SECTION_TYPE_MCE;
1103 		break;
1104 	default:
1105 		return -EINVAL;
1106 	}
1107 	rcd->sec_hdr.section_severity = CPER_SEV_FATAL;
1108 
1109 	ret = erst_write(&rcd->hdr);
1110 	*id = rcd->hdr.record_id;
1111 
1112 	return ret;
1113 }
1114 
1115 static int erst_clearer(enum pstore_type_id type, u64 id, int count,
1116 			struct timespec time, struct pstore_info *psi)
1117 {
1118 	return erst_clear(id);
1119 }
1120 
1121 static int __init erst_init(void)
1122 {
1123 	int rc = 0;
1124 	acpi_status status;
1125 	struct apei_exec_context ctx;
1126 	struct apei_resources erst_resources;
1127 	struct resource *r;
1128 	char *buf;
1129 
1130 	if (acpi_disabled)
1131 		goto err;
1132 
1133 	if (erst_disable) {
1134 		pr_info(
1135 	"Error Record Serialization Table (ERST) support is disabled.\n");
1136 		goto err;
1137 	}
1138 
1139 	status = acpi_get_table(ACPI_SIG_ERST, 0,
1140 				(struct acpi_table_header **)&erst_tab);
1141 	if (status == AE_NOT_FOUND)
1142 		goto err;
1143 	else if (ACPI_FAILURE(status)) {
1144 		const char *msg = acpi_format_exception(status);
1145 		pr_err("Failed to get table, %s\n", msg);
1146 		rc = -EINVAL;
1147 		goto err;
1148 	}
1149 
1150 	rc = erst_check_table(erst_tab);
1151 	if (rc) {
1152 		pr_err(FW_BUG "ERST table is invalid.\n");
1153 		goto err;
1154 	}
1155 
1156 	apei_resources_init(&erst_resources);
1157 	erst_exec_ctx_init(&ctx);
1158 	rc = apei_exec_collect_resources(&ctx, &erst_resources);
1159 	if (rc)
1160 		goto err_fini;
1161 	rc = apei_resources_request(&erst_resources, "APEI ERST");
1162 	if (rc)
1163 		goto err_fini;
1164 	rc = apei_exec_pre_map_gars(&ctx);
1165 	if (rc)
1166 		goto err_release;
1167 	rc = erst_get_erange(&erst_erange);
1168 	if (rc) {
1169 		if (rc == -ENODEV)
1170 			pr_info(
1171 	"The corresponding hardware device or firmware implementation "
1172 	"is not available.\n");
1173 		else
1174 			pr_err("Failed to get Error Log Address Range.\n");
1175 		goto err_unmap_reg;
1176 	}
1177 
1178 	r = request_mem_region(erst_erange.base, erst_erange.size, "APEI ERST");
1179 	if (!r) {
1180 		pr_err("Can not request [mem %#010llx-%#010llx] for ERST.\n",
1181 		       (unsigned long long)erst_erange.base,
1182 		       (unsigned long long)erst_erange.base + erst_erange.size - 1);
1183 		rc = -EIO;
1184 		goto err_unmap_reg;
1185 	}
1186 	rc = -ENOMEM;
1187 	erst_erange.vaddr = ioremap_cache(erst_erange.base,
1188 					  erst_erange.size);
1189 	if (!erst_erange.vaddr)
1190 		goto err_release_erange;
1191 
1192 	pr_info(
1193 	"Error Record Serialization Table (ERST) support is initialized.\n");
1194 
1195 	buf = kmalloc(erst_erange.size, GFP_KERNEL);
1196 	spin_lock_init(&erst_info.buf_lock);
1197 	if (buf) {
1198 		erst_info.buf = buf + sizeof(struct cper_pstore_record);
1199 		erst_info.bufsize = erst_erange.size -
1200 				    sizeof(struct cper_pstore_record);
1201 		rc = pstore_register(&erst_info);
1202 		if (rc) {
1203 			if (rc != -EPERM)
1204 				pr_info(
1205 				"Could not register with persistent store.\n");
1206 			erst_info.buf = NULL;
1207 			erst_info.bufsize = 0;
1208 			kfree(buf);
1209 		}
1210 	} else
1211 		pr_err(
1212 		"Failed to allocate %lld bytes for persistent store error log.\n",
1213 		erst_erange.size);
1214 
1215 	return 0;
1216 
1217 err_release_erange:
1218 	release_mem_region(erst_erange.base, erst_erange.size);
1219 err_unmap_reg:
1220 	apei_exec_post_unmap_gars(&ctx);
1221 err_release:
1222 	apei_resources_release(&erst_resources);
1223 err_fini:
1224 	apei_resources_fini(&erst_resources);
1225 err:
1226 	erst_disable = 1;
1227 	return rc;
1228 }
1229 
1230 device_initcall(erst_init);
1231