xref: /linux/drivers/remoteproc/remoteproc_coredump.c (revision 03c11eb3b16dc0058589751dfd91f254be2be613)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Coredump functionality for Remoteproc framework.
4  *
5  * Copyright (c) 2020, The Linux Foundation. All rights reserved.
6  */
7 
8 #include <linux/completion.h>
9 #include <linux/devcoredump.h>
10 #include <linux/device.h>
11 #include <linux/kernel.h>
12 #include <linux/remoteproc.h>
13 #include "remoteproc_internal.h"
14 #include "remoteproc_elf_helpers.h"
15 
16 struct rproc_coredump_state {
17 	struct rproc *rproc;
18 	void *header;
19 	struct completion dump_done;
20 };
21 
22 /**
23  * rproc_coredump_cleanup() - clean up dump_segments list
24  * @rproc: the remote processor handle
25  */
rproc_coredump_cleanup(struct rproc * rproc)26 void rproc_coredump_cleanup(struct rproc *rproc)
27 {
28 	struct rproc_dump_segment *entry, *tmp;
29 
30 	list_for_each_entry_safe(entry, tmp, &rproc->dump_segments, node) {
31 		list_del(&entry->node);
32 		kfree(entry);
33 	}
34 }
35 EXPORT_SYMBOL_GPL(rproc_coredump_cleanup);
36 
37 /**
38  * rproc_coredump_add_segment() - add segment of device memory to coredump
39  * @rproc:	handle of a remote processor
40  * @da:		device address
41  * @size:	size of segment
42  *
43  * Add device memory to the list of segments to be included in a coredump for
44  * the remoteproc.
45  *
46  * Return: 0 on success, negative errno on error.
47  */
rproc_coredump_add_segment(struct rproc * rproc,dma_addr_t da,size_t size)48 int rproc_coredump_add_segment(struct rproc *rproc, dma_addr_t da, size_t size)
49 {
50 	struct rproc_dump_segment *segment;
51 
52 	segment = kzalloc(sizeof(*segment), GFP_KERNEL);
53 	if (!segment)
54 		return -ENOMEM;
55 
56 	segment->da = da;
57 	segment->size = size;
58 
59 	list_add_tail(&segment->node, &rproc->dump_segments);
60 
61 	return 0;
62 }
63 EXPORT_SYMBOL(rproc_coredump_add_segment);
64 
65 /**
66  * rproc_coredump_add_custom_segment() - add custom coredump segment
67  * @rproc:	handle of a remote processor
68  * @da:		device address
69  * @size:	size of segment
70  * @dumpfn:	custom dump function called for each segment during coredump
71  * @priv:	private data
72  *
73  * Add device memory to the list of segments to be included in the coredump
74  * and associate the segment with the given custom dump function and private
75  * data.
76  *
77  * Return: 0 on success, negative errno on error.
78  */
rproc_coredump_add_custom_segment(struct rproc * rproc,dma_addr_t da,size_t size,void (* dumpfn)(struct rproc * rproc,struct rproc_dump_segment * segment,void * dest,size_t offset,size_t size),void * priv)79 int rproc_coredump_add_custom_segment(struct rproc *rproc,
80 				      dma_addr_t da, size_t size,
81 				      void (*dumpfn)(struct rproc *rproc,
82 						     struct rproc_dump_segment *segment,
83 						     void *dest, size_t offset,
84 						     size_t size),
85 				      void *priv)
86 {
87 	struct rproc_dump_segment *segment;
88 
89 	segment = kzalloc(sizeof(*segment), GFP_KERNEL);
90 	if (!segment)
91 		return -ENOMEM;
92 
93 	segment->da = da;
94 	segment->size = size;
95 	segment->priv = priv;
96 	segment->dump = dumpfn;
97 
98 	list_add_tail(&segment->node, &rproc->dump_segments);
99 
100 	return 0;
101 }
102 EXPORT_SYMBOL(rproc_coredump_add_custom_segment);
103 
104 /**
105  * rproc_coredump_set_elf_info() - set coredump elf information
106  * @rproc:	handle of a remote processor
107  * @class:	elf class for coredump elf file
108  * @machine:	elf machine for coredump elf file
109  *
110  * Set elf information which will be used for coredump elf file.
111  *
112  * Return: 0 on success, negative errno on error.
113  */
rproc_coredump_set_elf_info(struct rproc * rproc,u8 class,u16 machine)114 int rproc_coredump_set_elf_info(struct rproc *rproc, u8 class, u16 machine)
115 {
116 	if (class != ELFCLASS64 && class != ELFCLASS32)
117 		return -EINVAL;
118 
119 	rproc->elf_class = class;
120 	rproc->elf_machine = machine;
121 
122 	return 0;
123 }
124 EXPORT_SYMBOL(rproc_coredump_set_elf_info);
125 
rproc_coredump_free(void * data)126 static void rproc_coredump_free(void *data)
127 {
128 	struct rproc_coredump_state *dump_state = data;
129 
130 	vfree(dump_state->header);
131 	complete(&dump_state->dump_done);
132 }
133 
rproc_coredump_find_segment(loff_t user_offset,struct list_head * segments,size_t * data_left)134 static void *rproc_coredump_find_segment(loff_t user_offset,
135 					 struct list_head *segments,
136 					 size_t *data_left)
137 {
138 	struct rproc_dump_segment *segment;
139 
140 	list_for_each_entry(segment, segments, node) {
141 		if (user_offset < segment->size) {
142 			*data_left = segment->size - user_offset;
143 			return segment;
144 		}
145 		user_offset -= segment->size;
146 	}
147 
148 	*data_left = 0;
149 	return NULL;
150 }
151 
rproc_copy_segment(struct rproc * rproc,void * dest,struct rproc_dump_segment * segment,size_t offset,size_t size)152 static void rproc_copy_segment(struct rproc *rproc, void *dest,
153 			       struct rproc_dump_segment *segment,
154 			       size_t offset, size_t size)
155 {
156 	bool is_iomem = false;
157 	void *ptr;
158 
159 	if (segment->dump) {
160 		segment->dump(rproc, segment, dest, offset, size);
161 	} else {
162 		ptr = rproc_da_to_va(rproc, segment->da + offset, size, &is_iomem);
163 		if (!ptr) {
164 			dev_err(&rproc->dev,
165 				"invalid copy request for segment %pad with offset %zu and size %zu)\n",
166 				&segment->da, offset, size);
167 			memset(dest, 0xff, size);
168 		} else {
169 			if (is_iomem)
170 				memcpy_fromio(dest, (void const __iomem *)ptr, size);
171 			else
172 				memcpy(dest, ptr, size);
173 		}
174 	}
175 }
176 
rproc_coredump_read(char * buffer,loff_t offset,size_t count,void * data,size_t header_sz)177 static ssize_t rproc_coredump_read(char *buffer, loff_t offset, size_t count,
178 				   void *data, size_t header_sz)
179 {
180 	size_t seg_data, bytes_left = count;
181 	ssize_t copy_sz;
182 	struct rproc_dump_segment *seg;
183 	struct rproc_coredump_state *dump_state = data;
184 	struct rproc *rproc = dump_state->rproc;
185 	void *elfcore = dump_state->header;
186 
187 	/* Copy the vmalloc'ed header first. */
188 	if (offset < header_sz) {
189 		copy_sz = memory_read_from_buffer(buffer, count, &offset,
190 						  elfcore, header_sz);
191 
192 		return copy_sz;
193 	}
194 
195 	/*
196 	 * Find out the segment memory chunk to be copied based on offset.
197 	 * Keep copying data until count bytes are read.
198 	 */
199 	while (bytes_left) {
200 		seg = rproc_coredump_find_segment(offset - header_sz,
201 						  &rproc->dump_segments,
202 						  &seg_data);
203 		/* EOF check */
204 		if (!seg) {
205 			dev_info(&rproc->dev, "Ramdump done, %lld bytes read",
206 				 offset);
207 			break;
208 		}
209 
210 		copy_sz = min_t(size_t, bytes_left, seg_data);
211 
212 		rproc_copy_segment(rproc, buffer, seg, seg->size - seg_data,
213 				   copy_sz);
214 
215 		offset += copy_sz;
216 		buffer += copy_sz;
217 		bytes_left -= copy_sz;
218 	}
219 
220 	return count - bytes_left;
221 }
222 
223 /**
224  * rproc_coredump() - perform coredump
225  * @rproc:	rproc handle
226  *
227  * This function will generate an ELF header for the registered segments
228  * and create a devcoredump device associated with rproc. Based on the
229  * coredump configuration this function will directly copy the segments
230  * from device memory to userspace or copy segments from device memory to
231  * a separate buffer, which can then be read by userspace.
232  * The first approach avoids using extra vmalloc memory. But it will stall
233  * recovery flow until dump is read by userspace.
234  */
rproc_coredump(struct rproc * rproc)235 void rproc_coredump(struct rproc *rproc)
236 {
237 	struct rproc_dump_segment *segment;
238 	void *phdr;
239 	void *ehdr;
240 	size_t data_size;
241 	size_t offset;
242 	void *data;
243 	u8 class = rproc->elf_class;
244 	int phnum = 0;
245 	struct rproc_coredump_state dump_state;
246 	enum rproc_dump_mechanism dump_conf = rproc->dump_conf;
247 
248 	if (list_empty(&rproc->dump_segments) ||
249 	    dump_conf == RPROC_COREDUMP_DISABLED)
250 		return;
251 
252 	if (class == ELFCLASSNONE) {
253 		dev_err(&rproc->dev, "ELF class is not set\n");
254 		return;
255 	}
256 
257 	data_size = elf_size_of_hdr(class);
258 	list_for_each_entry(segment, &rproc->dump_segments, node) {
259 		/*
260 		 * For default configuration buffer includes headers & segments.
261 		 * For inline dump buffer just includes headers as segments are
262 		 * directly read from device memory.
263 		 */
264 		data_size += elf_size_of_phdr(class);
265 		if (dump_conf == RPROC_COREDUMP_ENABLED)
266 			data_size += segment->size;
267 
268 		phnum++;
269 	}
270 
271 	data = vmalloc(data_size);
272 	if (!data)
273 		return;
274 
275 	ehdr = data;
276 
277 	memset(ehdr, 0, elf_size_of_hdr(class));
278 	/* e_ident field is common for both elf32 and elf64 */
279 	elf_hdr_init_ident(ehdr, class);
280 
281 	elf_hdr_set_e_type(class, ehdr, ET_CORE);
282 	elf_hdr_set_e_machine(class, ehdr, rproc->elf_machine);
283 	elf_hdr_set_e_version(class, ehdr, EV_CURRENT);
284 	elf_hdr_set_e_entry(class, ehdr, rproc->bootaddr);
285 	elf_hdr_set_e_phoff(class, ehdr, elf_size_of_hdr(class));
286 	elf_hdr_set_e_ehsize(class, ehdr, elf_size_of_hdr(class));
287 	elf_hdr_set_e_phentsize(class, ehdr, elf_size_of_phdr(class));
288 	elf_hdr_set_e_phnum(class, ehdr, phnum);
289 
290 	phdr = data + elf_hdr_get_e_phoff(class, ehdr);
291 	offset = elf_hdr_get_e_phoff(class, ehdr);
292 	offset += elf_size_of_phdr(class) * elf_hdr_get_e_phnum(class, ehdr);
293 
294 	list_for_each_entry(segment, &rproc->dump_segments, node) {
295 		memset(phdr, 0, elf_size_of_phdr(class));
296 		elf_phdr_set_p_type(class, phdr, PT_LOAD);
297 		elf_phdr_set_p_offset(class, phdr, offset);
298 		elf_phdr_set_p_vaddr(class, phdr, segment->da);
299 		elf_phdr_set_p_paddr(class, phdr, segment->da);
300 		elf_phdr_set_p_filesz(class, phdr, segment->size);
301 		elf_phdr_set_p_memsz(class, phdr, segment->size);
302 		elf_phdr_set_p_flags(class, phdr, PF_R | PF_W | PF_X);
303 		elf_phdr_set_p_align(class, phdr, 0);
304 
305 		if (dump_conf == RPROC_COREDUMP_ENABLED)
306 			rproc_copy_segment(rproc, data + offset, segment, 0,
307 					   segment->size);
308 
309 		offset += elf_phdr_get_p_filesz(class, phdr);
310 		phdr += elf_size_of_phdr(class);
311 	}
312 	if (dump_conf == RPROC_COREDUMP_ENABLED) {
313 		dev_coredumpv(&rproc->dev, data, data_size, GFP_KERNEL);
314 		return;
315 	}
316 
317 	/* Initialize the dump state struct to be used by rproc_coredump_read */
318 	dump_state.rproc = rproc;
319 	dump_state.header = data;
320 	init_completion(&dump_state.dump_done);
321 
322 	dev_coredumpm(&rproc->dev, NULL, &dump_state, data_size, GFP_KERNEL,
323 		      rproc_coredump_read, rproc_coredump_free);
324 
325 	/*
326 	 * Wait until the dump is read and free is called. Data is freed
327 	 * by devcoredump framework automatically after 5 minutes.
328 	 */
329 	wait_for_completion(&dump_state.dump_done);
330 }
331 EXPORT_SYMBOL_GPL(rproc_coredump);
332 
333 /**
334  * rproc_coredump_using_sections() - perform coredump using section headers
335  * @rproc:	rproc handle
336  *
337  * This function will generate an ELF header for the registered sections of
338  * segments and create a devcoredump device associated with rproc. Based on
339  * the coredump configuration this function will directly copy the segments
340  * from device memory to userspace or copy segments from device memory to
341  * a separate buffer, which can then be read by userspace.
342  * The first approach avoids using extra vmalloc memory. But it will stall
343  * recovery flow until dump is read by userspace.
344  */
rproc_coredump_using_sections(struct rproc * rproc)345 void rproc_coredump_using_sections(struct rproc *rproc)
346 {
347 	struct rproc_dump_segment *segment;
348 	void *shdr;
349 	void *ehdr;
350 	size_t data_size;
351 	size_t strtbl_size = 0;
352 	size_t strtbl_index = 1;
353 	size_t offset;
354 	void *data;
355 	u8 class = rproc->elf_class;
356 	int shnum;
357 	struct rproc_coredump_state dump_state;
358 	unsigned int dump_conf = rproc->dump_conf;
359 	char *str_tbl = "STR_TBL";
360 
361 	if (list_empty(&rproc->dump_segments) ||
362 	    dump_conf == RPROC_COREDUMP_DISABLED)
363 		return;
364 
365 	if (class == ELFCLASSNONE) {
366 		dev_err(&rproc->dev, "ELF class is not set\n");
367 		return;
368 	}
369 
370 	/*
371 	 * We allocate two extra section headers. The first one is null.
372 	 * Second section header is for the string table. Also space is
373 	 * allocated for string table.
374 	 */
375 	data_size = elf_size_of_hdr(class) + 2 * elf_size_of_shdr(class);
376 	shnum = 2;
377 
378 	/* the extra byte is for the null character at index 0 */
379 	strtbl_size += strlen(str_tbl) + 2;
380 
381 	list_for_each_entry(segment, &rproc->dump_segments, node) {
382 		data_size += elf_size_of_shdr(class);
383 		strtbl_size += strlen(segment->priv) + 1;
384 		if (dump_conf == RPROC_COREDUMP_ENABLED)
385 			data_size += segment->size;
386 		shnum++;
387 	}
388 
389 	data_size += strtbl_size;
390 
391 	data = vmalloc(data_size);
392 	if (!data)
393 		return;
394 
395 	ehdr = data;
396 	memset(ehdr, 0, elf_size_of_hdr(class));
397 	/* e_ident field is common for both elf32 and elf64 */
398 	elf_hdr_init_ident(ehdr, class);
399 
400 	elf_hdr_set_e_type(class, ehdr, ET_CORE);
401 	elf_hdr_set_e_machine(class, ehdr, rproc->elf_machine);
402 	elf_hdr_set_e_version(class, ehdr, EV_CURRENT);
403 	elf_hdr_set_e_entry(class, ehdr, rproc->bootaddr);
404 	elf_hdr_set_e_shoff(class, ehdr, elf_size_of_hdr(class));
405 	elf_hdr_set_e_ehsize(class, ehdr, elf_size_of_hdr(class));
406 	elf_hdr_set_e_shentsize(class, ehdr, elf_size_of_shdr(class));
407 	elf_hdr_set_e_shnum(class, ehdr, shnum);
408 	elf_hdr_set_e_shstrndx(class, ehdr, 1);
409 
410 	/*
411 	 * The zeroth index of the section header is reserved and is rarely used.
412 	 * Set the section header as null (SHN_UNDEF) and move to the next one.
413 	 */
414 	shdr = data + elf_hdr_get_e_shoff(class, ehdr);
415 	memset(shdr, 0, elf_size_of_shdr(class));
416 	shdr += elf_size_of_shdr(class);
417 
418 	/* Initialize the string table. */
419 	offset = elf_hdr_get_e_shoff(class, ehdr) +
420 		 elf_size_of_shdr(class) * elf_hdr_get_e_shnum(class, ehdr);
421 	memset(data + offset, 0, strtbl_size);
422 
423 	/* Fill in the string table section header. */
424 	memset(shdr, 0, elf_size_of_shdr(class));
425 	elf_shdr_set_sh_type(class, shdr, SHT_STRTAB);
426 	elf_shdr_set_sh_offset(class, shdr, offset);
427 	elf_shdr_set_sh_size(class, shdr, strtbl_size);
428 	elf_shdr_set_sh_entsize(class, shdr, 0);
429 	elf_shdr_set_sh_flags(class, shdr, 0);
430 	elf_shdr_set_sh_name(class, shdr, elf_strtbl_add(str_tbl, ehdr, class, &strtbl_index));
431 	offset += elf_shdr_get_sh_size(class, shdr);
432 	shdr += elf_size_of_shdr(class);
433 
434 	list_for_each_entry(segment, &rproc->dump_segments, node) {
435 		memset(shdr, 0, elf_size_of_shdr(class));
436 		elf_shdr_set_sh_type(class, shdr, SHT_PROGBITS);
437 		elf_shdr_set_sh_offset(class, shdr, offset);
438 		elf_shdr_set_sh_addr(class, shdr, segment->da);
439 		elf_shdr_set_sh_size(class, shdr, segment->size);
440 		elf_shdr_set_sh_entsize(class, shdr, 0);
441 		elf_shdr_set_sh_flags(class, shdr, SHF_WRITE);
442 		elf_shdr_set_sh_name(class, shdr,
443 				     elf_strtbl_add(segment->priv, ehdr, class, &strtbl_index));
444 
445 		/* No need to copy segments for inline dumps */
446 		if (dump_conf == RPROC_COREDUMP_ENABLED)
447 			rproc_copy_segment(rproc, data + offset, segment, 0,
448 					   segment->size);
449 		offset += elf_shdr_get_sh_size(class, shdr);
450 		shdr += elf_size_of_shdr(class);
451 	}
452 
453 	if (dump_conf == RPROC_COREDUMP_ENABLED) {
454 		dev_coredumpv(&rproc->dev, data, data_size, GFP_KERNEL);
455 		return;
456 	}
457 
458 	/* Initialize the dump state struct to be used by rproc_coredump_read */
459 	dump_state.rproc = rproc;
460 	dump_state.header = data;
461 	init_completion(&dump_state.dump_done);
462 
463 	dev_coredumpm(&rproc->dev, NULL, &dump_state, data_size, GFP_KERNEL,
464 		      rproc_coredump_read, rproc_coredump_free);
465 
466 	/* Wait until the dump is read and free is called. Data is freed
467 	 * by devcoredump framework automatically after 5 minutes.
468 	 */
469 	wait_for_completion(&dump_state.dump_done);
470 }
471 EXPORT_SYMBOL(rproc_coredump_using_sections);
472