drivers/remoteproc/remoteproc_coredump.c

   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  */
  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  */
  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  */
  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  */
 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
 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
 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
 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
 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  */
 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  */
 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);