xref: /openbmc/linux/fs/pstore/ram.c (revision 3c881e05c814c970e4f9577446a9d3461d134607)
1  // SPDX-License-Identifier: GPL-2.0-only
2  /*
3   * RAM Oops/Panic logger
4   *
5   * Copyright (C) 2010 Marco Stornelli <marco.stornelli@gmail.com>
6   * Copyright (C) 2011 Kees Cook <keescook@chromium.org>
7   */
8  
9  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10  
11  #include <linux/kernel.h>
12  #include <linux/err.h>
13  #include <linux/module.h>
14  #include <linux/version.h>
15  #include <linux/pstore.h>
16  #include <linux/io.h>
17  #include <linux/ioport.h>
18  #include <linux/platform_device.h>
19  #include <linux/slab.h>
20  #include <linux/compiler.h>
21  #include <linux/pstore_ram.h>
22  #include <linux/of.h>
23  #include <linux/of_address.h>
24  #include "internal.h"
25  
26  #define RAMOOPS_KERNMSG_HDR "===="
27  #define MIN_MEM_SIZE 4096UL
28  
29  static ulong record_size = MIN_MEM_SIZE;
30  module_param(record_size, ulong, 0400);
31  MODULE_PARM_DESC(record_size,
32  		"size of each dump done on oops/panic");
33  
34  static ulong ramoops_console_size = MIN_MEM_SIZE;
35  module_param_named(console_size, ramoops_console_size, ulong, 0400);
36  MODULE_PARM_DESC(console_size, "size of kernel console log");
37  
38  static ulong ramoops_ftrace_size = MIN_MEM_SIZE;
39  module_param_named(ftrace_size, ramoops_ftrace_size, ulong, 0400);
40  MODULE_PARM_DESC(ftrace_size, "size of ftrace log");
41  
42  static ulong ramoops_pmsg_size = MIN_MEM_SIZE;
43  module_param_named(pmsg_size, ramoops_pmsg_size, ulong, 0400);
44  MODULE_PARM_DESC(pmsg_size, "size of user space message log");
45  
46  static unsigned long long mem_address;
47  module_param_hw(mem_address, ullong, other, 0400);
48  MODULE_PARM_DESC(mem_address,
49  		"start of reserved RAM used to store oops/panic logs");
50  
51  static ulong mem_size;
52  module_param(mem_size, ulong, 0400);
53  MODULE_PARM_DESC(mem_size,
54  		"size of reserved RAM used to store oops/panic logs");
55  
56  static unsigned int mem_type;
57  module_param(mem_type, uint, 0400);
58  MODULE_PARM_DESC(mem_type,
59  		"memory type: 0=write-combined (default), 1=unbuffered, 2=cached");
60  
61  static int ramoops_max_reason = -1;
62  module_param_named(max_reason, ramoops_max_reason, int, 0400);
63  MODULE_PARM_DESC(max_reason,
64  		 "maximum reason for kmsg dump (default 2: Oops and Panic) ");
65  
66  static int ramoops_ecc;
67  module_param_named(ecc, ramoops_ecc, int, 0400);
68  MODULE_PARM_DESC(ramoops_ecc,
69  		"if non-zero, the option enables ECC support and specifies "
70  		"ECC buffer size in bytes (1 is a special value, means 16 "
71  		"bytes ECC)");
72  
73  static int ramoops_dump_oops = -1;
74  module_param_named(dump_oops, ramoops_dump_oops, int, 0400);
75  MODULE_PARM_DESC(dump_oops,
76  		 "(deprecated: use max_reason instead) set to 1 to dump oopses & panics, 0 to only dump panics");
77  
78  struct ramoops_context {
79  	struct persistent_ram_zone **dprzs;	/* Oops dump zones */
80  	struct persistent_ram_zone *cprz;	/* Console zone */
81  	struct persistent_ram_zone **fprzs;	/* Ftrace zones */
82  	struct persistent_ram_zone *mprz;	/* PMSG zone */
83  	phys_addr_t phys_addr;
84  	unsigned long size;
85  	unsigned int memtype;
86  	size_t record_size;
87  	size_t console_size;
88  	size_t ftrace_size;
89  	size_t pmsg_size;
90  	u32 flags;
91  	struct persistent_ram_ecc_info ecc_info;
92  	unsigned int max_dump_cnt;
93  	unsigned int dump_write_cnt;
94  	/* _read_cnt need clear on ramoops_pstore_open */
95  	unsigned int dump_read_cnt;
96  	unsigned int console_read_cnt;
97  	unsigned int max_ftrace_cnt;
98  	unsigned int ftrace_read_cnt;
99  	unsigned int pmsg_read_cnt;
100  	struct pstore_info pstore;
101  };
102  
103  static struct platform_device *dummy;
104  
105  static int ramoops_pstore_open(struct pstore_info *psi)
106  {
107  	struct ramoops_context *cxt = psi->data;
108  
109  	cxt->dump_read_cnt = 0;
110  	cxt->console_read_cnt = 0;
111  	cxt->ftrace_read_cnt = 0;
112  	cxt->pmsg_read_cnt = 0;
113  	return 0;
114  }
115  
116  static struct persistent_ram_zone *
117  ramoops_get_next_prz(struct persistent_ram_zone *przs[], int id,
118  		     struct pstore_record *record)
119  {
120  	struct persistent_ram_zone *prz;
121  
122  	/* Give up if we never existed or have hit the end. */
123  	if (!przs)
124  		return NULL;
125  
126  	prz = przs[id];
127  	if (!prz)
128  		return NULL;
129  
130  	/* Update old/shadowed buffer. */
131  	if (prz->type == PSTORE_TYPE_DMESG)
132  		persistent_ram_save_old(prz);
133  
134  	if (!persistent_ram_old_size(prz))
135  		return NULL;
136  
137  	record->type = prz->type;
138  	record->id = id;
139  
140  	return prz;
141  }
142  
143  static int ramoops_read_kmsg_hdr(char *buffer, struct timespec64 *time,
144  				  bool *compressed)
145  {
146  	char data_type;
147  	int header_length = 0;
148  
149  	if (sscanf(buffer, RAMOOPS_KERNMSG_HDR "%lld.%lu-%c\n%n",
150  		   (time64_t *)&time->tv_sec, &time->tv_nsec, &data_type,
151  		   &header_length) == 3) {
152  		time->tv_nsec *= 1000;
153  		if (data_type == 'C')
154  			*compressed = true;
155  		else
156  			*compressed = false;
157  	} else if (sscanf(buffer, RAMOOPS_KERNMSG_HDR "%lld.%lu\n%n",
158  			  (time64_t *)&time->tv_sec, &time->tv_nsec,
159  			  &header_length) == 2) {
160  		time->tv_nsec *= 1000;
161  		*compressed = false;
162  	} else {
163  		time->tv_sec = 0;
164  		time->tv_nsec = 0;
165  		*compressed = false;
166  	}
167  	return header_length;
168  }
169  
170  static bool prz_ok(struct persistent_ram_zone *prz)
171  {
172  	return !!prz && !!(persistent_ram_old_size(prz) +
173  			   persistent_ram_ecc_string(prz, NULL, 0));
174  }
175  
176  static ssize_t ramoops_pstore_read(struct pstore_record *record)
177  {
178  	ssize_t size = 0;
179  	struct ramoops_context *cxt = record->psi->data;
180  	struct persistent_ram_zone *prz = NULL;
181  	int header_length = 0;
182  	bool free_prz = false;
183  
184  	/*
185  	 * Ramoops headers provide time stamps for PSTORE_TYPE_DMESG, but
186  	 * PSTORE_TYPE_CONSOLE and PSTORE_TYPE_FTRACE don't currently have
187  	 * valid time stamps, so it is initialized to zero.
188  	 */
189  	record->time.tv_sec = 0;
190  	record->time.tv_nsec = 0;
191  	record->compressed = false;
192  
193  	/* Find the next valid persistent_ram_zone for DMESG */
194  	while (cxt->dump_read_cnt < cxt->max_dump_cnt && !prz) {
195  		prz = ramoops_get_next_prz(cxt->dprzs, cxt->dump_read_cnt++,
196  					   record);
197  		if (!prz_ok(prz))
198  			continue;
199  		header_length = ramoops_read_kmsg_hdr(persistent_ram_old(prz),
200  						      &record->time,
201  						      &record->compressed);
202  		/* Clear and skip this DMESG record if it has no valid header */
203  		if (!header_length) {
204  			persistent_ram_free_old(prz);
205  			persistent_ram_zap(prz);
206  			prz = NULL;
207  		}
208  	}
209  
210  	if (!prz_ok(prz) && !cxt->console_read_cnt++)
211  		prz = ramoops_get_next_prz(&cxt->cprz, 0 /* single */, record);
212  
213  	if (!prz_ok(prz) && !cxt->pmsg_read_cnt++)
214  		prz = ramoops_get_next_prz(&cxt->mprz, 0 /* single */, record);
215  
216  	/* ftrace is last since it may want to dynamically allocate memory. */
217  	if (!prz_ok(prz)) {
218  		if (!(cxt->flags & RAMOOPS_FLAG_FTRACE_PER_CPU) &&
219  		    !cxt->ftrace_read_cnt++) {
220  			prz = ramoops_get_next_prz(cxt->fprzs, 0 /* single */,
221  						   record);
222  		} else {
223  			/*
224  			 * Build a new dummy record which combines all the
225  			 * per-cpu records including metadata and ecc info.
226  			 */
227  			struct persistent_ram_zone *tmp_prz, *prz_next;
228  
229  			tmp_prz = kzalloc(sizeof(struct persistent_ram_zone),
230  					  GFP_KERNEL);
231  			if (!tmp_prz)
232  				return -ENOMEM;
233  			prz = tmp_prz;
234  			free_prz = true;
235  
236  			while (cxt->ftrace_read_cnt < cxt->max_ftrace_cnt) {
237  				prz_next = ramoops_get_next_prz(cxt->fprzs,
238  						cxt->ftrace_read_cnt++, record);
239  
240  				if (!prz_ok(prz_next))
241  					continue;
242  
243  				tmp_prz->ecc_info = prz_next->ecc_info;
244  				tmp_prz->corrected_bytes +=
245  						prz_next->corrected_bytes;
246  				tmp_prz->bad_blocks += prz_next->bad_blocks;
247  
248  				size = pstore_ftrace_combine_log(
249  						&tmp_prz->old_log,
250  						&tmp_prz->old_log_size,
251  						prz_next->old_log,
252  						prz_next->old_log_size);
253  				if (size)
254  					goto out;
255  			}
256  			record->id = 0;
257  		}
258  	}
259  
260  	if (!prz_ok(prz)) {
261  		size = 0;
262  		goto out;
263  	}
264  
265  	size = persistent_ram_old_size(prz) - header_length;
266  
267  	/* ECC correction notice */
268  	record->ecc_notice_size = persistent_ram_ecc_string(prz, NULL, 0);
269  
270  	record->buf = kmalloc(size + record->ecc_notice_size + 1, GFP_KERNEL);
271  	if (record->buf == NULL) {
272  		size = -ENOMEM;
273  		goto out;
274  	}
275  
276  	memcpy(record->buf, (char *)persistent_ram_old(prz) + header_length,
277  	       size);
278  
279  	persistent_ram_ecc_string(prz, record->buf + size,
280  				  record->ecc_notice_size + 1);
281  
282  out:
283  	if (free_prz) {
284  		kfree(prz->old_log);
285  		kfree(prz);
286  	}
287  
288  	return size;
289  }
290  
291  static size_t ramoops_write_kmsg_hdr(struct persistent_ram_zone *prz,
292  				     struct pstore_record *record)
293  {
294  	char hdr[36]; /* "===="(4), %lld(20), "."(1), %06lu(6), "-%c\n"(3) */
295  	size_t len;
296  
297  	len = scnprintf(hdr, sizeof(hdr),
298  		RAMOOPS_KERNMSG_HDR "%lld.%06lu-%c\n",
299  		(time64_t)record->time.tv_sec,
300  		record->time.tv_nsec / 1000,
301  		record->compressed ? 'C' : 'D');
302  	persistent_ram_write(prz, hdr, len);
303  
304  	return len;
305  }
306  
307  static int notrace ramoops_pstore_write(struct pstore_record *record)
308  {
309  	struct ramoops_context *cxt = record->psi->data;
310  	struct persistent_ram_zone *prz;
311  	size_t size, hlen;
312  
313  	if (record->type == PSTORE_TYPE_CONSOLE) {
314  		if (!cxt->cprz)
315  			return -ENOMEM;
316  		persistent_ram_write(cxt->cprz, record->buf, record->size);
317  		return 0;
318  	} else if (record->type == PSTORE_TYPE_FTRACE) {
319  		int zonenum;
320  
321  		if (!cxt->fprzs)
322  			return -ENOMEM;
323  		/*
324  		 * Choose zone by if we're using per-cpu buffers.
325  		 */
326  		if (cxt->flags & RAMOOPS_FLAG_FTRACE_PER_CPU)
327  			zonenum = smp_processor_id();
328  		else
329  			zonenum = 0;
330  
331  		persistent_ram_write(cxt->fprzs[zonenum], record->buf,
332  				     record->size);
333  		return 0;
334  	} else if (record->type == PSTORE_TYPE_PMSG) {
335  		pr_warn_ratelimited("PMSG shouldn't call %s\n", __func__);
336  		return -EINVAL;
337  	}
338  
339  	if (record->type != PSTORE_TYPE_DMESG)
340  		return -EINVAL;
341  
342  	/*
343  	 * We could filter on record->reason here if we wanted to (which
344  	 * would duplicate what happened before the "max_reason" setting
345  	 * was added), but that would defeat the purpose of a system
346  	 * changing printk.always_kmsg_dump, so instead log everything that
347  	 * the kmsg dumper sends us, since it should be doing the filtering
348  	 * based on the combination of printk.always_kmsg_dump and our
349  	 * requested "max_reason".
350  	 */
351  
352  	/*
353  	 * Explicitly only take the first part of any new crash.
354  	 * If our buffer is larger than kmsg_bytes, this can never happen,
355  	 * and if our buffer is smaller than kmsg_bytes, we don't want the
356  	 * report split across multiple records.
357  	 */
358  	if (record->part != 1)
359  		return -ENOSPC;
360  
361  	if (!cxt->dprzs)
362  		return -ENOSPC;
363  
364  	prz = cxt->dprzs[cxt->dump_write_cnt];
365  
366  	/*
367  	 * Since this is a new crash dump, we need to reset the buffer in
368  	 * case it still has an old dump present. Without this, the new dump
369  	 * will get appended, which would seriously confuse anything trying
370  	 * to check dump file contents. Specifically, ramoops_read_kmsg_hdr()
371  	 * expects to find a dump header in the beginning of buffer data, so
372  	 * we must to reset the buffer values, in order to ensure that the
373  	 * header will be written to the beginning of the buffer.
374  	 */
375  	persistent_ram_zap(prz);
376  
377  	/* Build header and append record contents. */
378  	hlen = ramoops_write_kmsg_hdr(prz, record);
379  	if (!hlen)
380  		return -ENOMEM;
381  
382  	size = record->size;
383  	if (size + hlen > prz->buffer_size)
384  		size = prz->buffer_size - hlen;
385  	persistent_ram_write(prz, record->buf, size);
386  
387  	cxt->dump_write_cnt = (cxt->dump_write_cnt + 1) % cxt->max_dump_cnt;
388  
389  	return 0;
390  }
391  
392  static int notrace ramoops_pstore_write_user(struct pstore_record *record,
393  					     const char __user *buf)
394  {
395  	if (record->type == PSTORE_TYPE_PMSG) {
396  		struct ramoops_context *cxt = record->psi->data;
397  
398  		if (!cxt->mprz)
399  			return -ENOMEM;
400  		return persistent_ram_write_user(cxt->mprz, buf, record->size);
401  	}
402  
403  	return -EINVAL;
404  }
405  
406  static int ramoops_pstore_erase(struct pstore_record *record)
407  {
408  	struct ramoops_context *cxt = record->psi->data;
409  	struct persistent_ram_zone *prz;
410  
411  	switch (record->type) {
412  	case PSTORE_TYPE_DMESG:
413  		if (record->id >= cxt->max_dump_cnt)
414  			return -EINVAL;
415  		prz = cxt->dprzs[record->id];
416  		break;
417  	case PSTORE_TYPE_CONSOLE:
418  		prz = cxt->cprz;
419  		break;
420  	case PSTORE_TYPE_FTRACE:
421  		if (record->id >= cxt->max_ftrace_cnt)
422  			return -EINVAL;
423  		prz = cxt->fprzs[record->id];
424  		break;
425  	case PSTORE_TYPE_PMSG:
426  		prz = cxt->mprz;
427  		break;
428  	default:
429  		return -EINVAL;
430  	}
431  
432  	persistent_ram_free_old(prz);
433  	persistent_ram_zap(prz);
434  
435  	return 0;
436  }
437  
438  static struct ramoops_context oops_cxt = {
439  	.pstore = {
440  		.owner	= THIS_MODULE,
441  		.name	= "ramoops",
442  		.open	= ramoops_pstore_open,
443  		.read	= ramoops_pstore_read,
444  		.write	= ramoops_pstore_write,
445  		.write_user	= ramoops_pstore_write_user,
446  		.erase	= ramoops_pstore_erase,
447  	},
448  };
449  
450  static void ramoops_free_przs(struct ramoops_context *cxt)
451  {
452  	int i;
453  
454  	/* Free dump PRZs */
455  	if (cxt->dprzs) {
456  		for (i = 0; i < cxt->max_dump_cnt; i++)
457  			persistent_ram_free(cxt->dprzs[i]);
458  
459  		kfree(cxt->dprzs);
460  		cxt->max_dump_cnt = 0;
461  	}
462  
463  	/* Free ftrace PRZs */
464  	if (cxt->fprzs) {
465  		for (i = 0; i < cxt->max_ftrace_cnt; i++)
466  			persistent_ram_free(cxt->fprzs[i]);
467  		kfree(cxt->fprzs);
468  		cxt->max_ftrace_cnt = 0;
469  	}
470  }
471  
472  static int ramoops_init_przs(const char *name,
473  			     struct device *dev, struct ramoops_context *cxt,
474  			     struct persistent_ram_zone ***przs,
475  			     phys_addr_t *paddr, size_t mem_sz,
476  			     ssize_t record_size,
477  			     unsigned int *cnt, u32 sig, u32 flags)
478  {
479  	int err = -ENOMEM;
480  	int i;
481  	size_t zone_sz;
482  	struct persistent_ram_zone **prz_ar;
483  
484  	/* Allocate nothing for 0 mem_sz or 0 record_size. */
485  	if (mem_sz == 0 || record_size == 0) {
486  		*cnt = 0;
487  		return 0;
488  	}
489  
490  	/*
491  	 * If we have a negative record size, calculate it based on
492  	 * mem_sz / *cnt. If we have a positive record size, calculate
493  	 * cnt from mem_sz / record_size.
494  	 */
495  	if (record_size < 0) {
496  		if (*cnt == 0)
497  			return 0;
498  		record_size = mem_sz / *cnt;
499  		if (record_size == 0) {
500  			dev_err(dev, "%s record size == 0 (%zu / %u)\n",
501  				name, mem_sz, *cnt);
502  			goto fail;
503  		}
504  	} else {
505  		*cnt = mem_sz / record_size;
506  		if (*cnt == 0) {
507  			dev_err(dev, "%s record count == 0 (%zu / %zu)\n",
508  				name, mem_sz, record_size);
509  			goto fail;
510  		}
511  	}
512  
513  	if (*paddr + mem_sz - cxt->phys_addr > cxt->size) {
514  		dev_err(dev, "no room for %s mem region (0x%zx@0x%llx) in (0x%lx@0x%llx)\n",
515  			name,
516  			mem_sz, (unsigned long long)*paddr,
517  			cxt->size, (unsigned long long)cxt->phys_addr);
518  		goto fail;
519  	}
520  
521  	zone_sz = mem_sz / *cnt;
522  	if (!zone_sz) {
523  		dev_err(dev, "%s zone size == 0\n", name);
524  		goto fail;
525  	}
526  
527  	prz_ar = kcalloc(*cnt, sizeof(**przs), GFP_KERNEL);
528  	if (!prz_ar)
529  		goto fail;
530  
531  	for (i = 0; i < *cnt; i++) {
532  		char *label;
533  
534  		if (*cnt == 1)
535  			label = kasprintf(GFP_KERNEL, "ramoops:%s", name);
536  		else
537  			label = kasprintf(GFP_KERNEL, "ramoops:%s(%d/%d)",
538  					  name, i, *cnt - 1);
539  		prz_ar[i] = persistent_ram_new(*paddr, zone_sz, sig,
540  					       &cxt->ecc_info,
541  					       cxt->memtype, flags, label);
542  		kfree(label);
543  		if (IS_ERR(prz_ar[i])) {
544  			err = PTR_ERR(prz_ar[i]);
545  			dev_err(dev, "failed to request %s mem region (0x%zx@0x%llx): %d\n",
546  				name, record_size,
547  				(unsigned long long)*paddr, err);
548  
549  			while (i > 0) {
550  				i--;
551  				persistent_ram_free(prz_ar[i]);
552  			}
553  			kfree(prz_ar);
554  			goto fail;
555  		}
556  		*paddr += zone_sz;
557  		prz_ar[i]->type = pstore_name_to_type(name);
558  	}
559  
560  	*przs = prz_ar;
561  	return 0;
562  
563  fail:
564  	*cnt = 0;
565  	return err;
566  }
567  
568  static int ramoops_init_prz(const char *name,
569  			    struct device *dev, struct ramoops_context *cxt,
570  			    struct persistent_ram_zone **prz,
571  			    phys_addr_t *paddr, size_t sz, u32 sig)
572  {
573  	char *label;
574  
575  	if (!sz)
576  		return 0;
577  
578  	if (*paddr + sz - cxt->phys_addr > cxt->size) {
579  		dev_err(dev, "no room for %s mem region (0x%zx@0x%llx) in (0x%lx@0x%llx)\n",
580  			name, sz, (unsigned long long)*paddr,
581  			cxt->size, (unsigned long long)cxt->phys_addr);
582  		return -ENOMEM;
583  	}
584  
585  	label = kasprintf(GFP_KERNEL, "ramoops:%s", name);
586  	*prz = persistent_ram_new(*paddr, sz, sig, &cxt->ecc_info,
587  				  cxt->memtype, PRZ_FLAG_ZAP_OLD, label);
588  	kfree(label);
589  	if (IS_ERR(*prz)) {
590  		int err = PTR_ERR(*prz);
591  
592  		dev_err(dev, "failed to request %s mem region (0x%zx@0x%llx): %d\n",
593  			name, sz, (unsigned long long)*paddr, err);
594  		return err;
595  	}
596  
597  	*paddr += sz;
598  	(*prz)->type = pstore_name_to_type(name);
599  
600  	return 0;
601  }
602  
603  /* Read a u32 from a dt property and make sure it's safe for an int. */
604  static int ramoops_parse_dt_u32(struct platform_device *pdev,
605  				const char *propname,
606  				u32 default_value, u32 *value)
607  {
608  	u32 val32 = 0;
609  	int ret;
610  
611  	ret = of_property_read_u32(pdev->dev.of_node, propname, &val32);
612  	if (ret == -EINVAL) {
613  		/* field is missing, use default value. */
614  		val32 = default_value;
615  	} else if (ret < 0) {
616  		dev_err(&pdev->dev, "failed to parse property %s: %d\n",
617  			propname, ret);
618  		return ret;
619  	}
620  
621  	/* Sanity check our results. */
622  	if (val32 > INT_MAX) {
623  		dev_err(&pdev->dev, "%s %u > INT_MAX\n", propname, val32);
624  		return -EOVERFLOW;
625  	}
626  
627  	*value = val32;
628  	return 0;
629  }
630  
631  static int ramoops_parse_dt(struct platform_device *pdev,
632  			    struct ramoops_platform_data *pdata)
633  {
634  	struct device_node *of_node = pdev->dev.of_node;
635  	struct device_node *parent_node;
636  	struct resource *res;
637  	u32 value;
638  	int ret;
639  
640  	dev_dbg(&pdev->dev, "using Device Tree\n");
641  
642  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
643  	if (!res) {
644  		dev_err(&pdev->dev,
645  			"failed to locate DT /reserved-memory resource\n");
646  		return -EINVAL;
647  	}
648  
649  	pdata->mem_size = resource_size(res);
650  	pdata->mem_address = res->start;
651  	/*
652  	 * Setting "unbuffered" is deprecated and will be ignored if
653  	 * "mem_type" is also specified.
654  	 */
655  	pdata->mem_type = of_property_read_bool(of_node, "unbuffered");
656  	/*
657  	 * Setting "no-dump-oops" is deprecated and will be ignored if
658  	 * "max_reason" is also specified.
659  	 */
660  	if (of_property_read_bool(of_node, "no-dump-oops"))
661  		pdata->max_reason = KMSG_DUMP_PANIC;
662  	else
663  		pdata->max_reason = KMSG_DUMP_OOPS;
664  
665  #define parse_u32(name, field, default_value) {				\
666  		ret = ramoops_parse_dt_u32(pdev, name, default_value,	\
667  					    &value);			\
668  		if (ret < 0)						\
669  			return ret;					\
670  		field = value;						\
671  	}
672  
673  	parse_u32("mem-type", pdata->record_size, pdata->mem_type);
674  	parse_u32("record-size", pdata->record_size, 0);
675  	parse_u32("console-size", pdata->console_size, 0);
676  	parse_u32("ftrace-size", pdata->ftrace_size, 0);
677  	parse_u32("pmsg-size", pdata->pmsg_size, 0);
678  	parse_u32("ecc-size", pdata->ecc_info.ecc_size, 0);
679  	parse_u32("flags", pdata->flags, 0);
680  	parse_u32("max-reason", pdata->max_reason, pdata->max_reason);
681  
682  #undef parse_u32
683  
684  	/*
685  	 * Some old Chromebooks relied on the kernel setting the
686  	 * console_size and pmsg_size to the record size since that's
687  	 * what the downstream kernel did.  These same Chromebooks had
688  	 * "ramoops" straight under the root node which isn't
689  	 * according to the current upstream bindings (though it was
690  	 * arguably acceptable under a prior version of the bindings).
691  	 * Let's make those old Chromebooks work by detecting that
692  	 * we're not a child of "reserved-memory" and mimicking the
693  	 * expected behavior.
694  	 */
695  	parent_node = of_get_parent(of_node);
696  	if (!of_node_name_eq(parent_node, "reserved-memory") &&
697  	    !pdata->console_size && !pdata->ftrace_size &&
698  	    !pdata->pmsg_size && !pdata->ecc_info.ecc_size) {
699  		pdata->console_size = pdata->record_size;
700  		pdata->pmsg_size = pdata->record_size;
701  	}
702  	of_node_put(parent_node);
703  
704  	return 0;
705  }
706  
707  static int ramoops_probe(struct platform_device *pdev)
708  {
709  	struct device *dev = &pdev->dev;
710  	struct ramoops_platform_data *pdata = dev->platform_data;
711  	struct ramoops_platform_data pdata_local;
712  	struct ramoops_context *cxt = &oops_cxt;
713  	size_t dump_mem_sz;
714  	phys_addr_t paddr;
715  	int err = -EINVAL;
716  
717  	/*
718  	 * Only a single ramoops area allowed at a time, so fail extra
719  	 * probes.
720  	 */
721  	if (cxt->max_dump_cnt) {
722  		pr_err("already initialized\n");
723  		goto fail_out;
724  	}
725  
726  	if (dev_of_node(dev) && !pdata) {
727  		pdata = &pdata_local;
728  		memset(pdata, 0, sizeof(*pdata));
729  
730  		err = ramoops_parse_dt(pdev, pdata);
731  		if (err < 0)
732  			goto fail_out;
733  	}
734  
735  	/* Make sure we didn't get bogus platform data pointer. */
736  	if (!pdata) {
737  		pr_err("NULL platform data\n");
738  		goto fail_out;
739  	}
740  
741  	if (!pdata->mem_size || (!pdata->record_size && !pdata->console_size &&
742  			!pdata->ftrace_size && !pdata->pmsg_size)) {
743  		pr_err("The memory size and the record/console size must be "
744  			"non-zero\n");
745  		goto fail_out;
746  	}
747  
748  	if (pdata->record_size && !is_power_of_2(pdata->record_size))
749  		pdata->record_size = rounddown_pow_of_two(pdata->record_size);
750  	if (pdata->console_size && !is_power_of_2(pdata->console_size))
751  		pdata->console_size = rounddown_pow_of_two(pdata->console_size);
752  	if (pdata->ftrace_size && !is_power_of_2(pdata->ftrace_size))
753  		pdata->ftrace_size = rounddown_pow_of_two(pdata->ftrace_size);
754  	if (pdata->pmsg_size && !is_power_of_2(pdata->pmsg_size))
755  		pdata->pmsg_size = rounddown_pow_of_two(pdata->pmsg_size);
756  
757  	cxt->size = pdata->mem_size;
758  	cxt->phys_addr = pdata->mem_address;
759  	cxt->memtype = pdata->mem_type;
760  	cxt->record_size = pdata->record_size;
761  	cxt->console_size = pdata->console_size;
762  	cxt->ftrace_size = pdata->ftrace_size;
763  	cxt->pmsg_size = pdata->pmsg_size;
764  	cxt->flags = pdata->flags;
765  	cxt->ecc_info = pdata->ecc_info;
766  
767  	paddr = cxt->phys_addr;
768  
769  	dump_mem_sz = cxt->size - cxt->console_size - cxt->ftrace_size
770  			- cxt->pmsg_size;
771  	err = ramoops_init_przs("dmesg", dev, cxt, &cxt->dprzs, &paddr,
772  				dump_mem_sz, cxt->record_size,
773  				&cxt->max_dump_cnt, 0, 0);
774  	if (err)
775  		goto fail_out;
776  
777  	err = ramoops_init_prz("console", dev, cxt, &cxt->cprz, &paddr,
778  			       cxt->console_size, 0);
779  	if (err)
780  		goto fail_init_cprz;
781  
782  	cxt->max_ftrace_cnt = (cxt->flags & RAMOOPS_FLAG_FTRACE_PER_CPU)
783  				? nr_cpu_ids
784  				: 1;
785  	err = ramoops_init_przs("ftrace", dev, cxt, &cxt->fprzs, &paddr,
786  				cxt->ftrace_size, -1,
787  				&cxt->max_ftrace_cnt, LINUX_VERSION_CODE,
788  				(cxt->flags & RAMOOPS_FLAG_FTRACE_PER_CPU)
789  					? PRZ_FLAG_NO_LOCK : 0);
790  	if (err)
791  		goto fail_init_fprz;
792  
793  	err = ramoops_init_prz("pmsg", dev, cxt, &cxt->mprz, &paddr,
794  				cxt->pmsg_size, 0);
795  	if (err)
796  		goto fail_init_mprz;
797  
798  	cxt->pstore.data = cxt;
799  	/*
800  	 * Prepare frontend flags based on which areas are initialized.
801  	 * For ramoops_init_przs() cases, the "max count" variable tells
802  	 * if there are regions present. For ramoops_init_prz() cases,
803  	 * the single region size is how to check.
804  	 */
805  	cxt->pstore.flags = 0;
806  	if (cxt->max_dump_cnt) {
807  		cxt->pstore.flags |= PSTORE_FLAGS_DMESG;
808  		cxt->pstore.max_reason = pdata->max_reason;
809  	}
810  	if (cxt->console_size)
811  		cxt->pstore.flags |= PSTORE_FLAGS_CONSOLE;
812  	if (cxt->max_ftrace_cnt)
813  		cxt->pstore.flags |= PSTORE_FLAGS_FTRACE;
814  	if (cxt->pmsg_size)
815  		cxt->pstore.flags |= PSTORE_FLAGS_PMSG;
816  
817  	/*
818  	 * Since bufsize is only used for dmesg crash dumps, it
819  	 * must match the size of the dprz record (after PRZ header
820  	 * and ECC bytes have been accounted for).
821  	 */
822  	if (cxt->pstore.flags & PSTORE_FLAGS_DMESG) {
823  		cxt->pstore.bufsize = cxt->dprzs[0]->buffer_size;
824  		cxt->pstore.buf = kzalloc(cxt->pstore.bufsize, GFP_KERNEL);
825  		if (!cxt->pstore.buf) {
826  			pr_err("cannot allocate pstore crash dump buffer\n");
827  			err = -ENOMEM;
828  			goto fail_clear;
829  		}
830  	}
831  
832  	err = pstore_register(&cxt->pstore);
833  	if (err) {
834  		pr_err("registering with pstore failed\n");
835  		goto fail_buf;
836  	}
837  
838  	/*
839  	 * Update the module parameter variables as well so they are visible
840  	 * through /sys/module/ramoops/parameters/
841  	 */
842  	mem_size = pdata->mem_size;
843  	mem_address = pdata->mem_address;
844  	record_size = pdata->record_size;
845  	ramoops_max_reason = pdata->max_reason;
846  	ramoops_console_size = pdata->console_size;
847  	ramoops_pmsg_size = pdata->pmsg_size;
848  	ramoops_ftrace_size = pdata->ftrace_size;
849  
850  	pr_info("using 0x%lx@0x%llx, ecc: %d\n",
851  		cxt->size, (unsigned long long)cxt->phys_addr,
852  		cxt->ecc_info.ecc_size);
853  
854  	return 0;
855  
856  fail_buf:
857  	kfree(cxt->pstore.buf);
858  fail_clear:
859  	cxt->pstore.bufsize = 0;
860  	persistent_ram_free(cxt->mprz);
861  fail_init_mprz:
862  fail_init_fprz:
863  	persistent_ram_free(cxt->cprz);
864  fail_init_cprz:
865  	ramoops_free_przs(cxt);
866  fail_out:
867  	return err;
868  }
869  
870  static int ramoops_remove(struct platform_device *pdev)
871  {
872  	struct ramoops_context *cxt = &oops_cxt;
873  
874  	pstore_unregister(&cxt->pstore);
875  
876  	kfree(cxt->pstore.buf);
877  	cxt->pstore.bufsize = 0;
878  
879  	persistent_ram_free(cxt->mprz);
880  	persistent_ram_free(cxt->cprz);
881  	ramoops_free_przs(cxt);
882  
883  	return 0;
884  }
885  
886  static const struct of_device_id dt_match[] = {
887  	{ .compatible = "ramoops" },
888  	{}
889  };
890  
891  static struct platform_driver ramoops_driver = {
892  	.probe		= ramoops_probe,
893  	.remove		= ramoops_remove,
894  	.driver		= {
895  		.name		= "ramoops",
896  		.of_match_table	= dt_match,
897  	},
898  };
899  
900  static inline void ramoops_unregister_dummy(void)
901  {
902  	platform_device_unregister(dummy);
903  	dummy = NULL;
904  }
905  
906  static void __init ramoops_register_dummy(void)
907  {
908  	struct ramoops_platform_data pdata;
909  
910  	/*
911  	 * Prepare a dummy platform data structure to carry the module
912  	 * parameters. If mem_size isn't set, then there are no module
913  	 * parameters, and we can skip this.
914  	 */
915  	if (!mem_size)
916  		return;
917  
918  	pr_info("using module parameters\n");
919  
920  	memset(&pdata, 0, sizeof(pdata));
921  	pdata.mem_size = mem_size;
922  	pdata.mem_address = mem_address;
923  	pdata.mem_type = mem_type;
924  	pdata.record_size = record_size;
925  	pdata.console_size = ramoops_console_size;
926  	pdata.ftrace_size = ramoops_ftrace_size;
927  	pdata.pmsg_size = ramoops_pmsg_size;
928  	/* If "max_reason" is set, its value has priority over "dump_oops". */
929  	if (ramoops_max_reason >= 0)
930  		pdata.max_reason = ramoops_max_reason;
931  	/* Otherwise, if "dump_oops" is set, parse it into "max_reason". */
932  	else if (ramoops_dump_oops != -1)
933  		pdata.max_reason = ramoops_dump_oops ? KMSG_DUMP_OOPS
934  						     : KMSG_DUMP_PANIC;
935  	/* And if neither are explicitly set, use the default. */
936  	else
937  		pdata.max_reason = KMSG_DUMP_OOPS;
938  	pdata.flags = RAMOOPS_FLAG_FTRACE_PER_CPU;
939  
940  	/*
941  	 * For backwards compatibility ramoops.ecc=1 means 16 bytes ECC
942  	 * (using 1 byte for ECC isn't much of use anyway).
943  	 */
944  	pdata.ecc_info.ecc_size = ramoops_ecc == 1 ? 16 : ramoops_ecc;
945  
946  	dummy = platform_device_register_data(NULL, "ramoops", -1,
947  			&pdata, sizeof(pdata));
948  	if (IS_ERR(dummy)) {
949  		pr_info("could not create platform device: %ld\n",
950  			PTR_ERR(dummy));
951  		dummy = NULL;
952  	}
953  }
954  
955  static int __init ramoops_init(void)
956  {
957  	int ret;
958  
959  	ramoops_register_dummy();
960  	ret = platform_driver_register(&ramoops_driver);
961  	if (ret != 0)
962  		ramoops_unregister_dummy();
963  
964  	return ret;
965  }
966  postcore_initcall(ramoops_init);
967  
968  static void __exit ramoops_exit(void)
969  {
970  	platform_driver_unregister(&ramoops_driver);
971  	ramoops_unregister_dummy();
972  }
973  module_exit(ramoops_exit);
974  
975  MODULE_LICENSE("GPL");
976  MODULE_AUTHOR("Marco Stornelli <marco.stornelli@gmail.com>");
977  MODULE_DESCRIPTION("RAM Oops/Panic logger/driver");
978