xref: /openbmc/linux/fs/pstore/ram.c (revision b6bec26c)
1 /*
2  * RAM Oops/Panic logger
3  *
4  * Copyright (C) 2010 Marco Stornelli <marco.stornelli@gmail.com>
5  * Copyright (C) 2011 Kees Cook <keescook@chromium.org>
6  *
7  * This program is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU General Public License
9  * version 2 as published by the Free Software Foundation.
10  *
11  * This program is distributed in the hope that it will be useful, but
12  * WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14  * General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License
17  * along with this program; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
19  * 02110-1301 USA
20  *
21  */
22 
23 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
24 
25 #include <linux/kernel.h>
26 #include <linux/err.h>
27 #include <linux/module.h>
28 #include <linux/version.h>
29 #include <linux/pstore.h>
30 #include <linux/time.h>
31 #include <linux/io.h>
32 #include <linux/ioport.h>
33 #include <linux/platform_device.h>
34 #include <linux/slab.h>
35 #include <linux/compiler.h>
36 #include <linux/pstore_ram.h>
37 
38 #define RAMOOPS_KERNMSG_HDR "===="
39 #define MIN_MEM_SIZE 4096UL
40 
41 static ulong record_size = MIN_MEM_SIZE;
42 module_param(record_size, ulong, 0400);
43 MODULE_PARM_DESC(record_size,
44 		"size of each dump done on oops/panic");
45 
46 static ulong ramoops_console_size = MIN_MEM_SIZE;
47 module_param_named(console_size, ramoops_console_size, ulong, 0400);
48 MODULE_PARM_DESC(console_size, "size of kernel console log");
49 
50 static ulong ramoops_ftrace_size = MIN_MEM_SIZE;
51 module_param_named(ftrace_size, ramoops_ftrace_size, ulong, 0400);
52 MODULE_PARM_DESC(ftrace_size, "size of ftrace log");
53 
54 static ulong mem_address;
55 module_param(mem_address, ulong, 0400);
56 MODULE_PARM_DESC(mem_address,
57 		"start of reserved RAM used to store oops/panic logs");
58 
59 static ulong mem_size;
60 module_param(mem_size, ulong, 0400);
61 MODULE_PARM_DESC(mem_size,
62 		"size of reserved RAM used to store oops/panic logs");
63 
64 static int dump_oops = 1;
65 module_param(dump_oops, int, 0600);
66 MODULE_PARM_DESC(dump_oops,
67 		"set to 1 to dump oopses, 0 to only dump panics (default 1)");
68 
69 static int ramoops_ecc;
70 module_param_named(ecc, ramoops_ecc, int, 0600);
71 MODULE_PARM_DESC(ramoops_ecc,
72 		"if non-zero, the option enables ECC support and specifies "
73 		"ECC buffer size in bytes (1 is a special value, means 16 "
74 		"bytes ECC)");
75 
76 struct ramoops_context {
77 	struct persistent_ram_zone **przs;
78 	struct persistent_ram_zone *cprz;
79 	struct persistent_ram_zone *fprz;
80 	phys_addr_t phys_addr;
81 	unsigned long size;
82 	size_t record_size;
83 	size_t console_size;
84 	size_t ftrace_size;
85 	int dump_oops;
86 	int ecc_size;
87 	unsigned int max_dump_cnt;
88 	unsigned int dump_write_cnt;
89 	unsigned int dump_read_cnt;
90 	unsigned int console_read_cnt;
91 	unsigned int ftrace_read_cnt;
92 	struct pstore_info pstore;
93 };
94 
95 static struct platform_device *dummy;
96 static struct ramoops_platform_data *dummy_data;
97 
98 static int ramoops_pstore_open(struct pstore_info *psi)
99 {
100 	struct ramoops_context *cxt = psi->data;
101 
102 	cxt->dump_read_cnt = 0;
103 	cxt->console_read_cnt = 0;
104 	return 0;
105 }
106 
107 static struct persistent_ram_zone *
108 ramoops_get_next_prz(struct persistent_ram_zone *przs[], uint *c, uint max,
109 		     u64 *id,
110 		     enum pstore_type_id *typep, enum pstore_type_id type,
111 		     bool update)
112 {
113 	struct persistent_ram_zone *prz;
114 	int i = (*c)++;
115 
116 	if (i >= max)
117 		return NULL;
118 
119 	prz = przs[i];
120 
121 	if (update) {
122 		/* Update old/shadowed buffer. */
123 		persistent_ram_save_old(prz);
124 		if (!persistent_ram_old_size(prz))
125 			return NULL;
126 	}
127 
128 	*typep = type;
129 	*id = i;
130 
131 	return prz;
132 }
133 
134 static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type,
135 				   int *count, struct timespec *time,
136 				   char **buf, struct pstore_info *psi)
137 {
138 	ssize_t size;
139 	struct ramoops_context *cxt = psi->data;
140 	struct persistent_ram_zone *prz;
141 
142 	prz = ramoops_get_next_prz(cxt->przs, &cxt->dump_read_cnt,
143 				   cxt->max_dump_cnt, id, type,
144 				   PSTORE_TYPE_DMESG, 1);
145 	if (!prz)
146 		prz = ramoops_get_next_prz(&cxt->cprz, &cxt->console_read_cnt,
147 					   1, id, type, PSTORE_TYPE_CONSOLE, 0);
148 	if (!prz)
149 		prz = ramoops_get_next_prz(&cxt->fprz, &cxt->ftrace_read_cnt,
150 					   1, id, type, PSTORE_TYPE_FTRACE, 0);
151 	if (!prz)
152 		return 0;
153 
154 	/* TODO(kees): Bogus time for the moment. */
155 	time->tv_sec = 0;
156 	time->tv_nsec = 0;
157 
158 	size = persistent_ram_old_size(prz);
159 	*buf = kmalloc(size, GFP_KERNEL);
160 	if (*buf == NULL)
161 		return -ENOMEM;
162 	memcpy(*buf, persistent_ram_old(prz), size);
163 
164 	return size;
165 }
166 
167 static size_t ramoops_write_kmsg_hdr(struct persistent_ram_zone *prz)
168 {
169 	char *hdr;
170 	struct timeval timestamp;
171 	size_t len;
172 
173 	do_gettimeofday(&timestamp);
174 	hdr = kasprintf(GFP_ATOMIC, RAMOOPS_KERNMSG_HDR "%lu.%lu\n",
175 		(long)timestamp.tv_sec, (long)timestamp.tv_usec);
176 	WARN_ON_ONCE(!hdr);
177 	len = hdr ? strlen(hdr) : 0;
178 	persistent_ram_write(prz, hdr, len);
179 	kfree(hdr);
180 
181 	return len;
182 }
183 
184 static int notrace ramoops_pstore_write_buf(enum pstore_type_id type,
185 					    enum kmsg_dump_reason reason,
186 					    u64 *id, unsigned int part,
187 					    const char *buf, size_t size,
188 					    struct pstore_info *psi)
189 {
190 	struct ramoops_context *cxt = psi->data;
191 	struct persistent_ram_zone *prz;
192 	size_t hlen;
193 
194 	if (type == PSTORE_TYPE_CONSOLE) {
195 		if (!cxt->cprz)
196 			return -ENOMEM;
197 		persistent_ram_write(cxt->cprz, buf, size);
198 		return 0;
199 	} else if (type == PSTORE_TYPE_FTRACE) {
200 		if (!cxt->fprz)
201 			return -ENOMEM;
202 		persistent_ram_write(cxt->fprz, buf, size);
203 		return 0;
204 	}
205 
206 	if (type != PSTORE_TYPE_DMESG)
207 		return -EINVAL;
208 
209 	/* Out of the various dmesg dump types, ramoops is currently designed
210 	 * to only store crash logs, rather than storing general kernel logs.
211 	 */
212 	if (reason != KMSG_DUMP_OOPS &&
213 	    reason != KMSG_DUMP_PANIC)
214 		return -EINVAL;
215 
216 	/* Skip Oopes when configured to do so. */
217 	if (reason == KMSG_DUMP_OOPS && !cxt->dump_oops)
218 		return -EINVAL;
219 
220 	/* Explicitly only take the first part of any new crash.
221 	 * If our buffer is larger than kmsg_bytes, this can never happen,
222 	 * and if our buffer is smaller than kmsg_bytes, we don't want the
223 	 * report split across multiple records.
224 	 */
225 	if (part != 1)
226 		return -ENOSPC;
227 
228 	if (!cxt->przs)
229 		return -ENOSPC;
230 
231 	prz = cxt->przs[cxt->dump_write_cnt];
232 
233 	hlen = ramoops_write_kmsg_hdr(prz);
234 	if (size + hlen > prz->buffer_size)
235 		size = prz->buffer_size - hlen;
236 	persistent_ram_write(prz, buf, size);
237 
238 	cxt->dump_write_cnt = (cxt->dump_write_cnt + 1) % cxt->max_dump_cnt;
239 
240 	return 0;
241 }
242 
243 static int ramoops_pstore_erase(enum pstore_type_id type, u64 id, int count,
244 				struct timespec time, struct pstore_info *psi)
245 {
246 	struct ramoops_context *cxt = psi->data;
247 	struct persistent_ram_zone *prz;
248 
249 	switch (type) {
250 	case PSTORE_TYPE_DMESG:
251 		if (id >= cxt->max_dump_cnt)
252 			return -EINVAL;
253 		prz = cxt->przs[id];
254 		break;
255 	case PSTORE_TYPE_CONSOLE:
256 		prz = cxt->cprz;
257 		break;
258 	case PSTORE_TYPE_FTRACE:
259 		prz = cxt->fprz;
260 		break;
261 	default:
262 		return -EINVAL;
263 	}
264 
265 	persistent_ram_free_old(prz);
266 	persistent_ram_zap(prz);
267 
268 	return 0;
269 }
270 
271 static struct ramoops_context oops_cxt = {
272 	.pstore = {
273 		.owner	= THIS_MODULE,
274 		.name	= "ramoops",
275 		.open	= ramoops_pstore_open,
276 		.read	= ramoops_pstore_read,
277 		.write_buf	= ramoops_pstore_write_buf,
278 		.erase	= ramoops_pstore_erase,
279 	},
280 };
281 
282 static void ramoops_free_przs(struct ramoops_context *cxt)
283 {
284 	int i;
285 
286 	if (!cxt->przs)
287 		return;
288 
289 	for (i = 0; !IS_ERR_OR_NULL(cxt->przs[i]); i++)
290 		persistent_ram_free(cxt->przs[i]);
291 	kfree(cxt->przs);
292 }
293 
294 static int ramoops_init_przs(struct device *dev, struct ramoops_context *cxt,
295 			     phys_addr_t *paddr, size_t dump_mem_sz)
296 {
297 	int err = -ENOMEM;
298 	int i;
299 
300 	if (!cxt->record_size)
301 		return 0;
302 
303 	if (*paddr + dump_mem_sz - cxt->phys_addr > cxt->size) {
304 		dev_err(dev, "no room for dumps\n");
305 		return -ENOMEM;
306 	}
307 
308 	cxt->max_dump_cnt = dump_mem_sz / cxt->record_size;
309 	if (!cxt->max_dump_cnt)
310 		return -ENOMEM;
311 
312 	cxt->przs = kzalloc(sizeof(*cxt->przs) * cxt->max_dump_cnt,
313 			     GFP_KERNEL);
314 	if (!cxt->przs) {
315 		dev_err(dev, "failed to initialize a prz array for dumps\n");
316 		return -ENOMEM;
317 	}
318 
319 	for (i = 0; i < cxt->max_dump_cnt; i++) {
320 		size_t sz = cxt->record_size;
321 
322 		cxt->przs[i] = persistent_ram_new(*paddr, sz, 0, cxt->ecc_size);
323 		if (IS_ERR(cxt->przs[i])) {
324 			err = PTR_ERR(cxt->przs[i]);
325 			dev_err(dev, "failed to request mem region (0x%zx@0x%llx): %d\n",
326 				sz, (unsigned long long)*paddr, err);
327 			goto fail_prz;
328 		}
329 		*paddr += sz;
330 	}
331 
332 	return 0;
333 fail_prz:
334 	ramoops_free_przs(cxt);
335 	return err;
336 }
337 
338 static int ramoops_init_prz(struct device *dev, struct ramoops_context *cxt,
339 			    struct persistent_ram_zone **prz,
340 			    phys_addr_t *paddr, size_t sz, u32 sig)
341 {
342 	if (!sz)
343 		return 0;
344 
345 	if (*paddr + sz - cxt->phys_addr > cxt->size) {
346 		dev_err(dev, "no room for mem region (0x%zx@0x%llx) in (0x%lx@0x%llx)\n",
347 			sz, (unsigned long long)*paddr,
348 			cxt->size, (unsigned long long)cxt->phys_addr);
349 		return -ENOMEM;
350 	}
351 
352 	*prz = persistent_ram_new(*paddr, sz, sig, cxt->ecc_size);
353 	if (IS_ERR(*prz)) {
354 		int err = PTR_ERR(*prz);
355 
356 		dev_err(dev, "failed to request mem region (0x%zx@0x%llx): %d\n",
357 			sz, (unsigned long long)*paddr, err);
358 		return err;
359 	}
360 
361 	persistent_ram_zap(*prz);
362 
363 	*paddr += sz;
364 
365 	return 0;
366 }
367 
368 static int ramoops_probe(struct platform_device *pdev)
369 {
370 	struct device *dev = &pdev->dev;
371 	struct ramoops_platform_data *pdata = pdev->dev.platform_data;
372 	struct ramoops_context *cxt = &oops_cxt;
373 	size_t dump_mem_sz;
374 	phys_addr_t paddr;
375 	int err = -EINVAL;
376 
377 	/* Only a single ramoops area allowed at a time, so fail extra
378 	 * probes.
379 	 */
380 	if (cxt->max_dump_cnt)
381 		goto fail_out;
382 
383 	if (!pdata->mem_size || (!pdata->record_size && !pdata->console_size &&
384 			!pdata->ftrace_size)) {
385 		pr_err("The memory size and the record/console size must be "
386 			"non-zero\n");
387 		goto fail_out;
388 	}
389 
390 	if (!is_power_of_2(pdata->mem_size))
391 		pdata->mem_size = rounddown_pow_of_two(pdata->mem_size);
392 	if (!is_power_of_2(pdata->record_size))
393 		pdata->record_size = rounddown_pow_of_two(pdata->record_size);
394 	if (!is_power_of_2(pdata->console_size))
395 		pdata->console_size = rounddown_pow_of_two(pdata->console_size);
396 	if (!is_power_of_2(pdata->ftrace_size))
397 		pdata->ftrace_size = rounddown_pow_of_two(pdata->ftrace_size);
398 
399 	cxt->dump_read_cnt = 0;
400 	cxt->size = pdata->mem_size;
401 	cxt->phys_addr = pdata->mem_address;
402 	cxt->record_size = pdata->record_size;
403 	cxt->console_size = pdata->console_size;
404 	cxt->ftrace_size = pdata->ftrace_size;
405 	cxt->dump_oops = pdata->dump_oops;
406 	cxt->ecc_size = pdata->ecc_size;
407 
408 	paddr = cxt->phys_addr;
409 
410 	dump_mem_sz = cxt->size - cxt->console_size - cxt->ftrace_size;
411 	err = ramoops_init_przs(dev, cxt, &paddr, dump_mem_sz);
412 	if (err)
413 		goto fail_out;
414 
415 	err = ramoops_init_prz(dev, cxt, &cxt->cprz, &paddr,
416 			       cxt->console_size, 0);
417 	if (err)
418 		goto fail_init_cprz;
419 
420 	err = ramoops_init_prz(dev, cxt, &cxt->fprz, &paddr, cxt->ftrace_size,
421 			       LINUX_VERSION_CODE);
422 	if (err)
423 		goto fail_init_fprz;
424 
425 	if (!cxt->przs && !cxt->cprz && !cxt->fprz) {
426 		pr_err("memory size too small, minimum is %zu\n",
427 			cxt->console_size + cxt->record_size +
428 			cxt->ftrace_size);
429 		goto fail_cnt;
430 	}
431 
432 	cxt->pstore.data = cxt;
433 	/*
434 	 * Console can handle any buffer size, so prefer LOG_LINE_MAX. If we
435 	 * have to handle dumps, we must have at least record_size buffer. And
436 	 * for ftrace, bufsize is irrelevant (if bufsize is 0, buf will be
437 	 * ZERO_SIZE_PTR).
438 	 */
439 	if (cxt->console_size)
440 		cxt->pstore.bufsize = 1024; /* LOG_LINE_MAX */
441 	cxt->pstore.bufsize = max(cxt->record_size, cxt->pstore.bufsize);
442 	cxt->pstore.buf = kmalloc(cxt->pstore.bufsize, GFP_KERNEL);
443 	spin_lock_init(&cxt->pstore.buf_lock);
444 	if (!cxt->pstore.buf) {
445 		pr_err("cannot allocate pstore buffer\n");
446 		goto fail_clear;
447 	}
448 
449 	err = pstore_register(&cxt->pstore);
450 	if (err) {
451 		pr_err("registering with pstore failed\n");
452 		goto fail_buf;
453 	}
454 
455 	/*
456 	 * Update the module parameter variables as well so they are visible
457 	 * through /sys/module/ramoops/parameters/
458 	 */
459 	mem_size = pdata->mem_size;
460 	mem_address = pdata->mem_address;
461 	record_size = pdata->record_size;
462 	dump_oops = pdata->dump_oops;
463 
464 	pr_info("attached 0x%lx@0x%llx, ecc: %d\n",
465 		cxt->size, (unsigned long long)cxt->phys_addr,
466 		cxt->ecc_size);
467 
468 	return 0;
469 
470 fail_buf:
471 	kfree(cxt->pstore.buf);
472 fail_clear:
473 	cxt->pstore.bufsize = 0;
474 	cxt->max_dump_cnt = 0;
475 fail_cnt:
476 	kfree(cxt->fprz);
477 fail_init_fprz:
478 	kfree(cxt->cprz);
479 fail_init_cprz:
480 	ramoops_free_przs(cxt);
481 fail_out:
482 	return err;
483 }
484 
485 static int __exit ramoops_remove(struct platform_device *pdev)
486 {
487 #if 0
488 	/* TODO(kees): We cannot unload ramoops since pstore doesn't support
489 	 * unregistering yet.
490 	 */
491 	struct ramoops_context *cxt = &oops_cxt;
492 
493 	iounmap(cxt->virt_addr);
494 	release_mem_region(cxt->phys_addr, cxt->size);
495 	cxt->max_dump_cnt = 0;
496 
497 	/* TODO(kees): When pstore supports unregistering, call it here. */
498 	kfree(cxt->pstore.buf);
499 	cxt->pstore.bufsize = 0;
500 
501 	return 0;
502 #endif
503 	return -EBUSY;
504 }
505 
506 static struct platform_driver ramoops_driver = {
507 	.probe		= ramoops_probe,
508 	.remove		= __exit_p(ramoops_remove),
509 	.driver		= {
510 		.name	= "ramoops",
511 		.owner	= THIS_MODULE,
512 	},
513 };
514 
515 static void ramoops_register_dummy(void)
516 {
517 	if (!mem_size)
518 		return;
519 
520 	pr_info("using module parameters\n");
521 
522 	dummy_data = kzalloc(sizeof(*dummy_data), GFP_KERNEL);
523 	if (!dummy_data) {
524 		pr_info("could not allocate pdata\n");
525 		return;
526 	}
527 
528 	dummy_data->mem_size = mem_size;
529 	dummy_data->mem_address = mem_address;
530 	dummy_data->record_size = record_size;
531 	dummy_data->console_size = ramoops_console_size;
532 	dummy_data->ftrace_size = ramoops_ftrace_size;
533 	dummy_data->dump_oops = dump_oops;
534 	/*
535 	 * For backwards compatibility ramoops.ecc=1 means 16 bytes ECC
536 	 * (using 1 byte for ECC isn't much of use anyway).
537 	 */
538 	dummy_data->ecc_size = ramoops_ecc == 1 ? 16 : ramoops_ecc;
539 
540 	dummy = platform_device_register_data(NULL, "ramoops", -1,
541 			dummy_data, sizeof(struct ramoops_platform_data));
542 	if (IS_ERR(dummy)) {
543 		pr_info("could not create platform device: %ld\n",
544 			PTR_ERR(dummy));
545 	}
546 }
547 
548 static int __init ramoops_init(void)
549 {
550 	ramoops_register_dummy();
551 	return platform_driver_register(&ramoops_driver);
552 }
553 postcore_initcall(ramoops_init);
554 
555 static void __exit ramoops_exit(void)
556 {
557 	platform_driver_unregister(&ramoops_driver);
558 	platform_device_unregister(dummy);
559 	kfree(dummy_data);
560 }
561 module_exit(ramoops_exit);
562 
563 MODULE_LICENSE("GPL");
564 MODULE_AUTHOR("Marco Stornelli <marco.stornelli@gmail.com>");
565 MODULE_DESCRIPTION("RAM Oops/Panic logger/driver");
566