1 /* 2 * Firmware Assisted dump: A robust mechanism to get reliable kernel crash 3 * dump with assistance from firmware. This approach does not use kexec, 4 * instead firmware assists in booting the kdump kernel while preserving 5 * memory contents. The most of the code implementation has been adapted 6 * from phyp assisted dump implementation written by Linas Vepstas and 7 * Manish Ahuja 8 * 9 * This program is free software; you can redistribute it and/or modify 10 * it under the terms of the GNU General Public License as published by 11 * the Free Software Foundation; either version 2 of the License, or 12 * (at your option) any later version. 13 * 14 * This program is distributed in the hope that it will be useful, 15 * but WITHOUT ANY WARRANTY; without even the implied warranty of 16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 17 * GNU General Public License for more details. 18 * 19 * You should have received a copy of the GNU General Public License 20 * along with this program; if not, write to the Free Software 21 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. 22 * 23 * Copyright 2011 IBM Corporation 24 * Author: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> 25 */ 26 27 #undef DEBUG 28 #define pr_fmt(fmt) "fadump: " fmt 29 30 #include <linux/string.h> 31 #include <linux/memblock.h> 32 #include <linux/delay.h> 33 #include <linux/debugfs.h> 34 #include <linux/seq_file.h> 35 #include <linux/crash_dump.h> 36 #include <linux/kobject.h> 37 #include <linux/sysfs.h> 38 39 #include <asm/page.h> 40 #include <asm/prom.h> 41 #include <asm/rtas.h> 42 #include <asm/fadump.h> 43 #include <asm/debug.h> 44 #include <asm/setup.h> 45 46 static struct fw_dump fw_dump; 47 static struct fadump_mem_struct fdm; 48 static const struct fadump_mem_struct *fdm_active; 49 50 static DEFINE_MUTEX(fadump_mutex); 51 struct fad_crash_memory_ranges crash_memory_ranges[INIT_CRASHMEM_RANGES]; 52 int crash_mem_ranges; 53 54 /* Scan the Firmware Assisted dump configuration details. */ 55 int __init early_init_dt_scan_fw_dump(unsigned long node, 56 const char *uname, int depth, void *data) 57 { 58 __be32 *sections; 59 int i, num_sections; 60 unsigned long size; 61 const int *token; 62 63 if (depth != 1 || strcmp(uname, "rtas") != 0) 64 return 0; 65 66 /* 67 * Check if Firmware Assisted dump is supported. if yes, check 68 * if dump has been initiated on last reboot. 69 */ 70 token = of_get_flat_dt_prop(node, "ibm,configure-kernel-dump", NULL); 71 if (!token) 72 return 0; 73 74 fw_dump.fadump_supported = 1; 75 fw_dump.ibm_configure_kernel_dump = *token; 76 77 /* 78 * The 'ibm,kernel-dump' rtas node is present only if there is 79 * dump data waiting for us. 80 */ 81 fdm_active = of_get_flat_dt_prop(node, "ibm,kernel-dump", NULL); 82 if (fdm_active) 83 fw_dump.dump_active = 1; 84 85 /* Get the sizes required to store dump data for the firmware provided 86 * dump sections. 87 * For each dump section type supported, a 32bit cell which defines 88 * the ID of a supported section followed by two 32 bit cells which 89 * gives teh size of the section in bytes. 90 */ 91 sections = of_get_flat_dt_prop(node, "ibm,configure-kernel-dump-sizes", 92 &size); 93 94 if (!sections) 95 return 0; 96 97 num_sections = size / (3 * sizeof(u32)); 98 99 for (i = 0; i < num_sections; i++, sections += 3) { 100 u32 type = (u32)of_read_number(sections, 1); 101 102 switch (type) { 103 case FADUMP_CPU_STATE_DATA: 104 fw_dump.cpu_state_data_size = 105 of_read_ulong(§ions[1], 2); 106 break; 107 case FADUMP_HPTE_REGION: 108 fw_dump.hpte_region_size = 109 of_read_ulong(§ions[1], 2); 110 break; 111 } 112 } 113 return 1; 114 } 115 116 int is_fadump_active(void) 117 { 118 return fw_dump.dump_active; 119 } 120 121 /* Print firmware assisted dump configurations for debugging purpose. */ 122 static void fadump_show_config(void) 123 { 124 pr_debug("Support for firmware-assisted dump (fadump): %s\n", 125 (fw_dump.fadump_supported ? "present" : "no support")); 126 127 if (!fw_dump.fadump_supported) 128 return; 129 130 pr_debug("Fadump enabled : %s\n", 131 (fw_dump.fadump_enabled ? "yes" : "no")); 132 pr_debug("Dump Active : %s\n", 133 (fw_dump.dump_active ? "yes" : "no")); 134 pr_debug("Dump section sizes:\n"); 135 pr_debug(" CPU state data size: %lx\n", fw_dump.cpu_state_data_size); 136 pr_debug(" HPTE region size : %lx\n", fw_dump.hpte_region_size); 137 pr_debug("Boot memory size : %lx\n", fw_dump.boot_memory_size); 138 } 139 140 static unsigned long init_fadump_mem_struct(struct fadump_mem_struct *fdm, 141 unsigned long addr) 142 { 143 if (!fdm) 144 return 0; 145 146 memset(fdm, 0, sizeof(struct fadump_mem_struct)); 147 addr = addr & PAGE_MASK; 148 149 fdm->header.dump_format_version = 0x00000001; 150 fdm->header.dump_num_sections = 3; 151 fdm->header.dump_status_flag = 0; 152 fdm->header.offset_first_dump_section = 153 (u32)offsetof(struct fadump_mem_struct, cpu_state_data); 154 155 /* 156 * Fields for disk dump option. 157 * We are not using disk dump option, hence set these fields to 0. 158 */ 159 fdm->header.dd_block_size = 0; 160 fdm->header.dd_block_offset = 0; 161 fdm->header.dd_num_blocks = 0; 162 fdm->header.dd_offset_disk_path = 0; 163 164 /* set 0 to disable an automatic dump-reboot. */ 165 fdm->header.max_time_auto = 0; 166 167 /* Kernel dump sections */ 168 /* cpu state data section. */ 169 fdm->cpu_state_data.request_flag = FADUMP_REQUEST_FLAG; 170 fdm->cpu_state_data.source_data_type = FADUMP_CPU_STATE_DATA; 171 fdm->cpu_state_data.source_address = 0; 172 fdm->cpu_state_data.source_len = fw_dump.cpu_state_data_size; 173 fdm->cpu_state_data.destination_address = addr; 174 addr += fw_dump.cpu_state_data_size; 175 176 /* hpte region section */ 177 fdm->hpte_region.request_flag = FADUMP_REQUEST_FLAG; 178 fdm->hpte_region.source_data_type = FADUMP_HPTE_REGION; 179 fdm->hpte_region.source_address = 0; 180 fdm->hpte_region.source_len = fw_dump.hpte_region_size; 181 fdm->hpte_region.destination_address = addr; 182 addr += fw_dump.hpte_region_size; 183 184 /* RMA region section */ 185 fdm->rmr_region.request_flag = FADUMP_REQUEST_FLAG; 186 fdm->rmr_region.source_data_type = FADUMP_REAL_MODE_REGION; 187 fdm->rmr_region.source_address = RMA_START; 188 fdm->rmr_region.source_len = fw_dump.boot_memory_size; 189 fdm->rmr_region.destination_address = addr; 190 addr += fw_dump.boot_memory_size; 191 192 return addr; 193 } 194 195 /** 196 * fadump_calculate_reserve_size(): reserve variable boot area 5% of System RAM 197 * 198 * Function to find the largest memory size we need to reserve during early 199 * boot process. This will be the size of the memory that is required for a 200 * kernel to boot successfully. 201 * 202 * This function has been taken from phyp-assisted dump feature implementation. 203 * 204 * returns larger of 256MB or 5% rounded down to multiples of 256MB. 205 * 206 * TODO: Come up with better approach to find out more accurate memory size 207 * that is required for a kernel to boot successfully. 208 * 209 */ 210 static inline unsigned long fadump_calculate_reserve_size(void) 211 { 212 unsigned long size; 213 214 /* 215 * Check if the size is specified through fadump_reserve_mem= cmdline 216 * option. If yes, then use that. 217 */ 218 if (fw_dump.reserve_bootvar) 219 return fw_dump.reserve_bootvar; 220 221 /* divide by 20 to get 5% of value */ 222 size = memblock_end_of_DRAM() / 20; 223 224 /* round it down in multiples of 256 */ 225 size = size & ~0x0FFFFFFFUL; 226 227 /* Truncate to memory_limit. We don't want to over reserve the memory.*/ 228 if (memory_limit && size > memory_limit) 229 size = memory_limit; 230 231 return (size > MIN_BOOT_MEM ? size : MIN_BOOT_MEM); 232 } 233 234 /* 235 * Calculate the total memory size required to be reserved for 236 * firmware-assisted dump registration. 237 */ 238 static unsigned long get_fadump_area_size(void) 239 { 240 unsigned long size = 0; 241 242 size += fw_dump.cpu_state_data_size; 243 size += fw_dump.hpte_region_size; 244 size += fw_dump.boot_memory_size; 245 size += sizeof(struct fadump_crash_info_header); 246 size += sizeof(struct elfhdr); /* ELF core header.*/ 247 size += sizeof(struct elf_phdr); /* place holder for cpu notes */ 248 /* Program headers for crash memory regions. */ 249 size += sizeof(struct elf_phdr) * (memblock_num_regions(memory) + 2); 250 251 size = PAGE_ALIGN(size); 252 return size; 253 } 254 255 int __init fadump_reserve_mem(void) 256 { 257 unsigned long base, size, memory_boundary; 258 259 if (!fw_dump.fadump_enabled) 260 return 0; 261 262 if (!fw_dump.fadump_supported) { 263 printk(KERN_INFO "Firmware-assisted dump is not supported on" 264 " this hardware\n"); 265 fw_dump.fadump_enabled = 0; 266 return 0; 267 } 268 /* 269 * Initialize boot memory size 270 * If dump is active then we have already calculated the size during 271 * first kernel. 272 */ 273 if (fdm_active) 274 fw_dump.boot_memory_size = fdm_active->rmr_region.source_len; 275 else 276 fw_dump.boot_memory_size = fadump_calculate_reserve_size(); 277 278 /* 279 * Calculate the memory boundary. 280 * If memory_limit is less than actual memory boundary then reserve 281 * the memory for fadump beyond the memory_limit and adjust the 282 * memory_limit accordingly, so that the running kernel can run with 283 * specified memory_limit. 284 */ 285 if (memory_limit && memory_limit < memblock_end_of_DRAM()) { 286 size = get_fadump_area_size(); 287 if ((memory_limit + size) < memblock_end_of_DRAM()) 288 memory_limit += size; 289 else 290 memory_limit = memblock_end_of_DRAM(); 291 printk(KERN_INFO "Adjusted memory_limit for firmware-assisted" 292 " dump, now %#016llx\n", memory_limit); 293 } 294 if (memory_limit) 295 memory_boundary = memory_limit; 296 else 297 memory_boundary = memblock_end_of_DRAM(); 298 299 if (fw_dump.dump_active) { 300 printk(KERN_INFO "Firmware-assisted dump is active.\n"); 301 /* 302 * If last boot has crashed then reserve all the memory 303 * above boot_memory_size so that we don't touch it until 304 * dump is written to disk by userspace tool. This memory 305 * will be released for general use once the dump is saved. 306 */ 307 base = fw_dump.boot_memory_size; 308 size = memory_boundary - base; 309 memblock_reserve(base, size); 310 printk(KERN_INFO "Reserved %ldMB of memory at %ldMB " 311 "for saving crash dump\n", 312 (unsigned long)(size >> 20), 313 (unsigned long)(base >> 20)); 314 315 fw_dump.fadumphdr_addr = 316 fdm_active->rmr_region.destination_address + 317 fdm_active->rmr_region.source_len; 318 pr_debug("fadumphdr_addr = %p\n", 319 (void *) fw_dump.fadumphdr_addr); 320 } else { 321 /* Reserve the memory at the top of memory. */ 322 size = get_fadump_area_size(); 323 base = memory_boundary - size; 324 memblock_reserve(base, size); 325 printk(KERN_INFO "Reserved %ldMB of memory at %ldMB " 326 "for firmware-assisted dump\n", 327 (unsigned long)(size >> 20), 328 (unsigned long)(base >> 20)); 329 } 330 fw_dump.reserve_dump_area_start = base; 331 fw_dump.reserve_dump_area_size = size; 332 return 1; 333 } 334 335 /* Look for fadump= cmdline option. */ 336 static int __init early_fadump_param(char *p) 337 { 338 if (!p) 339 return 1; 340 341 if (strncmp(p, "on", 2) == 0) 342 fw_dump.fadump_enabled = 1; 343 else if (strncmp(p, "off", 3) == 0) 344 fw_dump.fadump_enabled = 0; 345 346 return 0; 347 } 348 early_param("fadump", early_fadump_param); 349 350 /* Look for fadump_reserve_mem= cmdline option */ 351 static int __init early_fadump_reserve_mem(char *p) 352 { 353 if (p) 354 fw_dump.reserve_bootvar = memparse(p, &p); 355 return 0; 356 } 357 early_param("fadump_reserve_mem", early_fadump_reserve_mem); 358 359 static void register_fw_dump(struct fadump_mem_struct *fdm) 360 { 361 int rc; 362 unsigned int wait_time; 363 364 pr_debug("Registering for firmware-assisted kernel dump...\n"); 365 366 /* TODO: Add upper time limit for the delay */ 367 do { 368 rc = rtas_call(fw_dump.ibm_configure_kernel_dump, 3, 1, NULL, 369 FADUMP_REGISTER, fdm, 370 sizeof(struct fadump_mem_struct)); 371 372 wait_time = rtas_busy_delay_time(rc); 373 if (wait_time) 374 mdelay(wait_time); 375 376 } while (wait_time); 377 378 switch (rc) { 379 case -1: 380 printk(KERN_ERR "Failed to register firmware-assisted kernel" 381 " dump. Hardware Error(%d).\n", rc); 382 break; 383 case -3: 384 printk(KERN_ERR "Failed to register firmware-assisted kernel" 385 " dump. Parameter Error(%d).\n", rc); 386 break; 387 case -9: 388 printk(KERN_ERR "firmware-assisted kernel dump is already " 389 " registered."); 390 fw_dump.dump_registered = 1; 391 break; 392 case 0: 393 printk(KERN_INFO "firmware-assisted kernel dump registration" 394 " is successful\n"); 395 fw_dump.dump_registered = 1; 396 break; 397 } 398 } 399 400 void crash_fadump(struct pt_regs *regs, const char *str) 401 { 402 struct fadump_crash_info_header *fdh = NULL; 403 404 if (!fw_dump.dump_registered || !fw_dump.fadumphdr_addr) 405 return; 406 407 fdh = __va(fw_dump.fadumphdr_addr); 408 crashing_cpu = smp_processor_id(); 409 fdh->crashing_cpu = crashing_cpu; 410 crash_save_vmcoreinfo(); 411 412 if (regs) 413 fdh->regs = *regs; 414 else 415 ppc_save_regs(&fdh->regs); 416 417 fdh->cpu_online_mask = *cpu_online_mask; 418 419 /* Call ibm,os-term rtas call to trigger firmware assisted dump */ 420 rtas_os_term((char *)str); 421 } 422 423 #define GPR_MASK 0xffffff0000000000 424 static inline int fadump_gpr_index(u64 id) 425 { 426 int i = -1; 427 char str[3]; 428 429 if ((id & GPR_MASK) == REG_ID("GPR")) { 430 /* get the digits at the end */ 431 id &= ~GPR_MASK; 432 id >>= 24; 433 str[2] = '\0'; 434 str[1] = id & 0xff; 435 str[0] = (id >> 8) & 0xff; 436 sscanf(str, "%d", &i); 437 if (i > 31) 438 i = -1; 439 } 440 return i; 441 } 442 443 static inline void fadump_set_regval(struct pt_regs *regs, u64 reg_id, 444 u64 reg_val) 445 { 446 int i; 447 448 i = fadump_gpr_index(reg_id); 449 if (i >= 0) 450 regs->gpr[i] = (unsigned long)reg_val; 451 else if (reg_id == REG_ID("NIA")) 452 regs->nip = (unsigned long)reg_val; 453 else if (reg_id == REG_ID("MSR")) 454 regs->msr = (unsigned long)reg_val; 455 else if (reg_id == REG_ID("CTR")) 456 regs->ctr = (unsigned long)reg_val; 457 else if (reg_id == REG_ID("LR")) 458 regs->link = (unsigned long)reg_val; 459 else if (reg_id == REG_ID("XER")) 460 regs->xer = (unsigned long)reg_val; 461 else if (reg_id == REG_ID("CR")) 462 regs->ccr = (unsigned long)reg_val; 463 else if (reg_id == REG_ID("DAR")) 464 regs->dar = (unsigned long)reg_val; 465 else if (reg_id == REG_ID("DSISR")) 466 regs->dsisr = (unsigned long)reg_val; 467 } 468 469 static struct fadump_reg_entry* 470 fadump_read_registers(struct fadump_reg_entry *reg_entry, struct pt_regs *regs) 471 { 472 memset(regs, 0, sizeof(struct pt_regs)); 473 474 while (reg_entry->reg_id != REG_ID("CPUEND")) { 475 fadump_set_regval(regs, reg_entry->reg_id, 476 reg_entry->reg_value); 477 reg_entry++; 478 } 479 reg_entry++; 480 return reg_entry; 481 } 482 483 static u32 *fadump_append_elf_note(u32 *buf, char *name, unsigned type, 484 void *data, size_t data_len) 485 { 486 struct elf_note note; 487 488 note.n_namesz = strlen(name) + 1; 489 note.n_descsz = data_len; 490 note.n_type = type; 491 memcpy(buf, ¬e, sizeof(note)); 492 buf += (sizeof(note) + 3)/4; 493 memcpy(buf, name, note.n_namesz); 494 buf += (note.n_namesz + 3)/4; 495 memcpy(buf, data, note.n_descsz); 496 buf += (note.n_descsz + 3)/4; 497 498 return buf; 499 } 500 501 static void fadump_final_note(u32 *buf) 502 { 503 struct elf_note note; 504 505 note.n_namesz = 0; 506 note.n_descsz = 0; 507 note.n_type = 0; 508 memcpy(buf, ¬e, sizeof(note)); 509 } 510 511 static u32 *fadump_regs_to_elf_notes(u32 *buf, struct pt_regs *regs) 512 { 513 struct elf_prstatus prstatus; 514 515 memset(&prstatus, 0, sizeof(prstatus)); 516 /* 517 * FIXME: How do i get PID? Do I really need it? 518 * prstatus.pr_pid = ???? 519 */ 520 elf_core_copy_kernel_regs(&prstatus.pr_reg, regs); 521 buf = fadump_append_elf_note(buf, KEXEC_CORE_NOTE_NAME, NT_PRSTATUS, 522 &prstatus, sizeof(prstatus)); 523 return buf; 524 } 525 526 static void fadump_update_elfcore_header(char *bufp) 527 { 528 struct elfhdr *elf; 529 struct elf_phdr *phdr; 530 531 elf = (struct elfhdr *)bufp; 532 bufp += sizeof(struct elfhdr); 533 534 /* First note is a place holder for cpu notes info. */ 535 phdr = (struct elf_phdr *)bufp; 536 537 if (phdr->p_type == PT_NOTE) { 538 phdr->p_paddr = fw_dump.cpu_notes_buf; 539 phdr->p_offset = phdr->p_paddr; 540 phdr->p_filesz = fw_dump.cpu_notes_buf_size; 541 phdr->p_memsz = fw_dump.cpu_notes_buf_size; 542 } 543 return; 544 } 545 546 static void *fadump_cpu_notes_buf_alloc(unsigned long size) 547 { 548 void *vaddr; 549 struct page *page; 550 unsigned long order, count, i; 551 552 order = get_order(size); 553 vaddr = (void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, order); 554 if (!vaddr) 555 return NULL; 556 557 count = 1 << order; 558 page = virt_to_page(vaddr); 559 for (i = 0; i < count; i++) 560 SetPageReserved(page + i); 561 return vaddr; 562 } 563 564 static void fadump_cpu_notes_buf_free(unsigned long vaddr, unsigned long size) 565 { 566 struct page *page; 567 unsigned long order, count, i; 568 569 order = get_order(size); 570 count = 1 << order; 571 page = virt_to_page(vaddr); 572 for (i = 0; i < count; i++) 573 ClearPageReserved(page + i); 574 __free_pages(page, order); 575 } 576 577 /* 578 * Read CPU state dump data and convert it into ELF notes. 579 * The CPU dump starts with magic number "REGSAVE". NumCpusOffset should be 580 * used to access the data to allow for additional fields to be added without 581 * affecting compatibility. Each list of registers for a CPU starts with 582 * "CPUSTRT" and ends with "CPUEND". Each register entry is of 16 bytes, 583 * 8 Byte ASCII identifier and 8 Byte register value. The register entry 584 * with identifier "CPUSTRT" and "CPUEND" contains 4 byte cpu id as part 585 * of register value. For more details refer to PAPR document. 586 * 587 * Only for the crashing cpu we ignore the CPU dump data and get exact 588 * state from fadump crash info structure populated by first kernel at the 589 * time of crash. 590 */ 591 static int __init fadump_build_cpu_notes(const struct fadump_mem_struct *fdm) 592 { 593 struct fadump_reg_save_area_header *reg_header; 594 struct fadump_reg_entry *reg_entry; 595 struct fadump_crash_info_header *fdh = NULL; 596 void *vaddr; 597 unsigned long addr; 598 u32 num_cpus, *note_buf; 599 struct pt_regs regs; 600 int i, rc = 0, cpu = 0; 601 602 if (!fdm->cpu_state_data.bytes_dumped) 603 return -EINVAL; 604 605 addr = fdm->cpu_state_data.destination_address; 606 vaddr = __va(addr); 607 608 reg_header = vaddr; 609 if (reg_header->magic_number != REGSAVE_AREA_MAGIC) { 610 printk(KERN_ERR "Unable to read register save area.\n"); 611 return -ENOENT; 612 } 613 pr_debug("--------CPU State Data------------\n"); 614 pr_debug("Magic Number: %llx\n", reg_header->magic_number); 615 pr_debug("NumCpuOffset: %x\n", reg_header->num_cpu_offset); 616 617 vaddr += reg_header->num_cpu_offset; 618 num_cpus = *((u32 *)(vaddr)); 619 pr_debug("NumCpus : %u\n", num_cpus); 620 vaddr += sizeof(u32); 621 reg_entry = (struct fadump_reg_entry *)vaddr; 622 623 /* Allocate buffer to hold cpu crash notes. */ 624 fw_dump.cpu_notes_buf_size = num_cpus * sizeof(note_buf_t); 625 fw_dump.cpu_notes_buf_size = PAGE_ALIGN(fw_dump.cpu_notes_buf_size); 626 note_buf = fadump_cpu_notes_buf_alloc(fw_dump.cpu_notes_buf_size); 627 if (!note_buf) { 628 printk(KERN_ERR "Failed to allocate 0x%lx bytes for " 629 "cpu notes buffer\n", fw_dump.cpu_notes_buf_size); 630 return -ENOMEM; 631 } 632 fw_dump.cpu_notes_buf = __pa(note_buf); 633 634 pr_debug("Allocated buffer for cpu notes of size %ld at %p\n", 635 (num_cpus * sizeof(note_buf_t)), note_buf); 636 637 if (fw_dump.fadumphdr_addr) 638 fdh = __va(fw_dump.fadumphdr_addr); 639 640 for (i = 0; i < num_cpus; i++) { 641 if (reg_entry->reg_id != REG_ID("CPUSTRT")) { 642 printk(KERN_ERR "Unable to read CPU state data\n"); 643 rc = -ENOENT; 644 goto error_out; 645 } 646 /* Lower 4 bytes of reg_value contains logical cpu id */ 647 cpu = reg_entry->reg_value & FADUMP_CPU_ID_MASK; 648 if (!cpumask_test_cpu(cpu, &fdh->cpu_online_mask)) { 649 SKIP_TO_NEXT_CPU(reg_entry); 650 continue; 651 } 652 pr_debug("Reading register data for cpu %d...\n", cpu); 653 if (fdh && fdh->crashing_cpu == cpu) { 654 regs = fdh->regs; 655 note_buf = fadump_regs_to_elf_notes(note_buf, ®s); 656 SKIP_TO_NEXT_CPU(reg_entry); 657 } else { 658 reg_entry++; 659 reg_entry = fadump_read_registers(reg_entry, ®s); 660 note_buf = fadump_regs_to_elf_notes(note_buf, ®s); 661 } 662 } 663 fadump_final_note(note_buf); 664 665 pr_debug("Updating elfcore header (%llx) with cpu notes\n", 666 fdh->elfcorehdr_addr); 667 fadump_update_elfcore_header((char *)__va(fdh->elfcorehdr_addr)); 668 return 0; 669 670 error_out: 671 fadump_cpu_notes_buf_free((unsigned long)__va(fw_dump.cpu_notes_buf), 672 fw_dump.cpu_notes_buf_size); 673 fw_dump.cpu_notes_buf = 0; 674 fw_dump.cpu_notes_buf_size = 0; 675 return rc; 676 677 } 678 679 /* 680 * Validate and process the dump data stored by firmware before exporting 681 * it through '/proc/vmcore'. 682 */ 683 static int __init process_fadump(const struct fadump_mem_struct *fdm_active) 684 { 685 struct fadump_crash_info_header *fdh; 686 int rc = 0; 687 688 if (!fdm_active || !fw_dump.fadumphdr_addr) 689 return -EINVAL; 690 691 /* Check if the dump data is valid. */ 692 if ((fdm_active->header.dump_status_flag == FADUMP_ERROR_FLAG) || 693 (fdm_active->cpu_state_data.error_flags != 0) || 694 (fdm_active->rmr_region.error_flags != 0)) { 695 printk(KERN_ERR "Dump taken by platform is not valid\n"); 696 return -EINVAL; 697 } 698 if ((fdm_active->rmr_region.bytes_dumped != 699 fdm_active->rmr_region.source_len) || 700 !fdm_active->cpu_state_data.bytes_dumped) { 701 printk(KERN_ERR "Dump taken by platform is incomplete\n"); 702 return -EINVAL; 703 } 704 705 /* Validate the fadump crash info header */ 706 fdh = __va(fw_dump.fadumphdr_addr); 707 if (fdh->magic_number != FADUMP_CRASH_INFO_MAGIC) { 708 printk(KERN_ERR "Crash info header is not valid.\n"); 709 return -EINVAL; 710 } 711 712 rc = fadump_build_cpu_notes(fdm_active); 713 if (rc) 714 return rc; 715 716 /* 717 * We are done validating dump info and elfcore header is now ready 718 * to be exported. set elfcorehdr_addr so that vmcore module will 719 * export the elfcore header through '/proc/vmcore'. 720 */ 721 elfcorehdr_addr = fdh->elfcorehdr_addr; 722 723 return 0; 724 } 725 726 static inline void fadump_add_crash_memory(unsigned long long base, 727 unsigned long long end) 728 { 729 if (base == end) 730 return; 731 732 pr_debug("crash_memory_range[%d] [%#016llx-%#016llx], %#llx bytes\n", 733 crash_mem_ranges, base, end - 1, (end - base)); 734 crash_memory_ranges[crash_mem_ranges].base = base; 735 crash_memory_ranges[crash_mem_ranges].size = end - base; 736 crash_mem_ranges++; 737 } 738 739 static void fadump_exclude_reserved_area(unsigned long long start, 740 unsigned long long end) 741 { 742 unsigned long long ra_start, ra_end; 743 744 ra_start = fw_dump.reserve_dump_area_start; 745 ra_end = ra_start + fw_dump.reserve_dump_area_size; 746 747 if ((ra_start < end) && (ra_end > start)) { 748 if ((start < ra_start) && (end > ra_end)) { 749 fadump_add_crash_memory(start, ra_start); 750 fadump_add_crash_memory(ra_end, end); 751 } else if (start < ra_start) { 752 fadump_add_crash_memory(start, ra_start); 753 } else if (ra_end < end) { 754 fadump_add_crash_memory(ra_end, end); 755 } 756 } else 757 fadump_add_crash_memory(start, end); 758 } 759 760 static int fadump_init_elfcore_header(char *bufp) 761 { 762 struct elfhdr *elf; 763 764 elf = (struct elfhdr *) bufp; 765 bufp += sizeof(struct elfhdr); 766 memcpy(elf->e_ident, ELFMAG, SELFMAG); 767 elf->e_ident[EI_CLASS] = ELF_CLASS; 768 elf->e_ident[EI_DATA] = ELF_DATA; 769 elf->e_ident[EI_VERSION] = EV_CURRENT; 770 elf->e_ident[EI_OSABI] = ELF_OSABI; 771 memset(elf->e_ident+EI_PAD, 0, EI_NIDENT-EI_PAD); 772 elf->e_type = ET_CORE; 773 elf->e_machine = ELF_ARCH; 774 elf->e_version = EV_CURRENT; 775 elf->e_entry = 0; 776 elf->e_phoff = sizeof(struct elfhdr); 777 elf->e_shoff = 0; 778 elf->e_flags = ELF_CORE_EFLAGS; 779 elf->e_ehsize = sizeof(struct elfhdr); 780 elf->e_phentsize = sizeof(struct elf_phdr); 781 elf->e_phnum = 0; 782 elf->e_shentsize = 0; 783 elf->e_shnum = 0; 784 elf->e_shstrndx = 0; 785 786 return 0; 787 } 788 789 /* 790 * Traverse through memblock structure and setup crash memory ranges. These 791 * ranges will be used create PT_LOAD program headers in elfcore header. 792 */ 793 static void fadump_setup_crash_memory_ranges(void) 794 { 795 struct memblock_region *reg; 796 unsigned long long start, end; 797 798 pr_debug("Setup crash memory ranges.\n"); 799 crash_mem_ranges = 0; 800 /* 801 * add the first memory chunk (RMA_START through boot_memory_size) as 802 * a separate memory chunk. The reason is, at the time crash firmware 803 * will move the content of this memory chunk to different location 804 * specified during fadump registration. We need to create a separate 805 * program header for this chunk with the correct offset. 806 */ 807 fadump_add_crash_memory(RMA_START, fw_dump.boot_memory_size); 808 809 for_each_memblock(memory, reg) { 810 start = (unsigned long long)reg->base; 811 end = start + (unsigned long long)reg->size; 812 if (start == RMA_START && end >= fw_dump.boot_memory_size) 813 start = fw_dump.boot_memory_size; 814 815 /* add this range excluding the reserved dump area. */ 816 fadump_exclude_reserved_area(start, end); 817 } 818 } 819 820 /* 821 * If the given physical address falls within the boot memory region then 822 * return the relocated address that points to the dump region reserved 823 * for saving initial boot memory contents. 824 */ 825 static inline unsigned long fadump_relocate(unsigned long paddr) 826 { 827 if (paddr > RMA_START && paddr < fw_dump.boot_memory_size) 828 return fdm.rmr_region.destination_address + paddr; 829 else 830 return paddr; 831 } 832 833 static int fadump_create_elfcore_headers(char *bufp) 834 { 835 struct elfhdr *elf; 836 struct elf_phdr *phdr; 837 int i; 838 839 fadump_init_elfcore_header(bufp); 840 elf = (struct elfhdr *)bufp; 841 bufp += sizeof(struct elfhdr); 842 843 /* 844 * setup ELF PT_NOTE, place holder for cpu notes info. The notes info 845 * will be populated during second kernel boot after crash. Hence 846 * this PT_NOTE will always be the first elf note. 847 * 848 * NOTE: Any new ELF note addition should be placed after this note. 849 */ 850 phdr = (struct elf_phdr *)bufp; 851 bufp += sizeof(struct elf_phdr); 852 phdr->p_type = PT_NOTE; 853 phdr->p_flags = 0; 854 phdr->p_vaddr = 0; 855 phdr->p_align = 0; 856 857 phdr->p_offset = 0; 858 phdr->p_paddr = 0; 859 phdr->p_filesz = 0; 860 phdr->p_memsz = 0; 861 862 (elf->e_phnum)++; 863 864 /* setup ELF PT_NOTE for vmcoreinfo */ 865 phdr = (struct elf_phdr *)bufp; 866 bufp += sizeof(struct elf_phdr); 867 phdr->p_type = PT_NOTE; 868 phdr->p_flags = 0; 869 phdr->p_vaddr = 0; 870 phdr->p_align = 0; 871 872 phdr->p_paddr = fadump_relocate(paddr_vmcoreinfo_note()); 873 phdr->p_offset = phdr->p_paddr; 874 phdr->p_memsz = vmcoreinfo_max_size; 875 phdr->p_filesz = vmcoreinfo_max_size; 876 877 /* Increment number of program headers. */ 878 (elf->e_phnum)++; 879 880 /* setup PT_LOAD sections. */ 881 882 for (i = 0; i < crash_mem_ranges; i++) { 883 unsigned long long mbase, msize; 884 mbase = crash_memory_ranges[i].base; 885 msize = crash_memory_ranges[i].size; 886 887 if (!msize) 888 continue; 889 890 phdr = (struct elf_phdr *)bufp; 891 bufp += sizeof(struct elf_phdr); 892 phdr->p_type = PT_LOAD; 893 phdr->p_flags = PF_R|PF_W|PF_X; 894 phdr->p_offset = mbase; 895 896 if (mbase == RMA_START) { 897 /* 898 * The entire RMA region will be moved by firmware 899 * to the specified destination_address. Hence set 900 * the correct offset. 901 */ 902 phdr->p_offset = fdm.rmr_region.destination_address; 903 } 904 905 phdr->p_paddr = mbase; 906 phdr->p_vaddr = (unsigned long)__va(mbase); 907 phdr->p_filesz = msize; 908 phdr->p_memsz = msize; 909 phdr->p_align = 0; 910 911 /* Increment number of program headers. */ 912 (elf->e_phnum)++; 913 } 914 return 0; 915 } 916 917 static unsigned long init_fadump_header(unsigned long addr) 918 { 919 struct fadump_crash_info_header *fdh; 920 921 if (!addr) 922 return 0; 923 924 fw_dump.fadumphdr_addr = addr; 925 fdh = __va(addr); 926 addr += sizeof(struct fadump_crash_info_header); 927 928 memset(fdh, 0, sizeof(struct fadump_crash_info_header)); 929 fdh->magic_number = FADUMP_CRASH_INFO_MAGIC; 930 fdh->elfcorehdr_addr = addr; 931 /* We will set the crashing cpu id in crash_fadump() during crash. */ 932 fdh->crashing_cpu = CPU_UNKNOWN; 933 934 return addr; 935 } 936 937 static void register_fadump(void) 938 { 939 unsigned long addr; 940 void *vaddr; 941 942 /* 943 * If no memory is reserved then we can not register for firmware- 944 * assisted dump. 945 */ 946 if (!fw_dump.reserve_dump_area_size) 947 return; 948 949 fadump_setup_crash_memory_ranges(); 950 951 addr = fdm.rmr_region.destination_address + fdm.rmr_region.source_len; 952 /* Initialize fadump crash info header. */ 953 addr = init_fadump_header(addr); 954 vaddr = __va(addr); 955 956 pr_debug("Creating ELF core headers at %#016lx\n", addr); 957 fadump_create_elfcore_headers(vaddr); 958 959 /* register the future kernel dump with firmware. */ 960 register_fw_dump(&fdm); 961 } 962 963 static int fadump_unregister_dump(struct fadump_mem_struct *fdm) 964 { 965 int rc = 0; 966 unsigned int wait_time; 967 968 pr_debug("Un-register firmware-assisted dump\n"); 969 970 /* TODO: Add upper time limit for the delay */ 971 do { 972 rc = rtas_call(fw_dump.ibm_configure_kernel_dump, 3, 1, NULL, 973 FADUMP_UNREGISTER, fdm, 974 sizeof(struct fadump_mem_struct)); 975 976 wait_time = rtas_busy_delay_time(rc); 977 if (wait_time) 978 mdelay(wait_time); 979 } while (wait_time); 980 981 if (rc) { 982 printk(KERN_ERR "Failed to un-register firmware-assisted dump." 983 " unexpected error(%d).\n", rc); 984 return rc; 985 } 986 fw_dump.dump_registered = 0; 987 return 0; 988 } 989 990 static int fadump_invalidate_dump(struct fadump_mem_struct *fdm) 991 { 992 int rc = 0; 993 unsigned int wait_time; 994 995 pr_debug("Invalidating firmware-assisted dump registration\n"); 996 997 /* TODO: Add upper time limit for the delay */ 998 do { 999 rc = rtas_call(fw_dump.ibm_configure_kernel_dump, 3, 1, NULL, 1000 FADUMP_INVALIDATE, fdm, 1001 sizeof(struct fadump_mem_struct)); 1002 1003 wait_time = rtas_busy_delay_time(rc); 1004 if (wait_time) 1005 mdelay(wait_time); 1006 } while (wait_time); 1007 1008 if (rc) { 1009 printk(KERN_ERR "Failed to invalidate firmware-assisted dump " 1010 "rgistration. unexpected error(%d).\n", rc); 1011 return rc; 1012 } 1013 fw_dump.dump_active = 0; 1014 fdm_active = NULL; 1015 return 0; 1016 } 1017 1018 void fadump_cleanup(void) 1019 { 1020 /* Invalidate the registration only if dump is active. */ 1021 if (fw_dump.dump_active) { 1022 init_fadump_mem_struct(&fdm, 1023 fdm_active->cpu_state_data.destination_address); 1024 fadump_invalidate_dump(&fdm); 1025 } 1026 } 1027 1028 /* 1029 * Release the memory that was reserved in early boot to preserve the memory 1030 * contents. The released memory will be available for general use. 1031 */ 1032 static void fadump_release_memory(unsigned long begin, unsigned long end) 1033 { 1034 unsigned long addr; 1035 unsigned long ra_start, ra_end; 1036 1037 ra_start = fw_dump.reserve_dump_area_start; 1038 ra_end = ra_start + fw_dump.reserve_dump_area_size; 1039 1040 for (addr = begin; addr < end; addr += PAGE_SIZE) { 1041 /* 1042 * exclude the dump reserve area. Will reuse it for next 1043 * fadump registration. 1044 */ 1045 if (addr <= ra_end && ((addr + PAGE_SIZE) > ra_start)) 1046 continue; 1047 1048 free_reserved_page(pfn_to_page(addr >> PAGE_SHIFT)); 1049 } 1050 } 1051 1052 static void fadump_invalidate_release_mem(void) 1053 { 1054 unsigned long reserved_area_start, reserved_area_end; 1055 unsigned long destination_address; 1056 1057 mutex_lock(&fadump_mutex); 1058 if (!fw_dump.dump_active) { 1059 mutex_unlock(&fadump_mutex); 1060 return; 1061 } 1062 1063 destination_address = fdm_active->cpu_state_data.destination_address; 1064 fadump_cleanup(); 1065 mutex_unlock(&fadump_mutex); 1066 1067 /* 1068 * Save the current reserved memory bounds we will require them 1069 * later for releasing the memory for general use. 1070 */ 1071 reserved_area_start = fw_dump.reserve_dump_area_start; 1072 reserved_area_end = reserved_area_start + 1073 fw_dump.reserve_dump_area_size; 1074 /* 1075 * Setup reserve_dump_area_start and its size so that we can 1076 * reuse this reserved memory for Re-registration. 1077 */ 1078 fw_dump.reserve_dump_area_start = destination_address; 1079 fw_dump.reserve_dump_area_size = get_fadump_area_size(); 1080 1081 fadump_release_memory(reserved_area_start, reserved_area_end); 1082 if (fw_dump.cpu_notes_buf) { 1083 fadump_cpu_notes_buf_free( 1084 (unsigned long)__va(fw_dump.cpu_notes_buf), 1085 fw_dump.cpu_notes_buf_size); 1086 fw_dump.cpu_notes_buf = 0; 1087 fw_dump.cpu_notes_buf_size = 0; 1088 } 1089 /* Initialize the kernel dump memory structure for FAD registration. */ 1090 init_fadump_mem_struct(&fdm, fw_dump.reserve_dump_area_start); 1091 } 1092 1093 static ssize_t fadump_release_memory_store(struct kobject *kobj, 1094 struct kobj_attribute *attr, 1095 const char *buf, size_t count) 1096 { 1097 if (!fw_dump.dump_active) 1098 return -EPERM; 1099 1100 if (buf[0] == '1') { 1101 /* 1102 * Take away the '/proc/vmcore'. We are releasing the dump 1103 * memory, hence it will not be valid anymore. 1104 */ 1105 vmcore_cleanup(); 1106 fadump_invalidate_release_mem(); 1107 1108 } else 1109 return -EINVAL; 1110 return count; 1111 } 1112 1113 static ssize_t fadump_enabled_show(struct kobject *kobj, 1114 struct kobj_attribute *attr, 1115 char *buf) 1116 { 1117 return sprintf(buf, "%d\n", fw_dump.fadump_enabled); 1118 } 1119 1120 static ssize_t fadump_register_show(struct kobject *kobj, 1121 struct kobj_attribute *attr, 1122 char *buf) 1123 { 1124 return sprintf(buf, "%d\n", fw_dump.dump_registered); 1125 } 1126 1127 static ssize_t fadump_register_store(struct kobject *kobj, 1128 struct kobj_attribute *attr, 1129 const char *buf, size_t count) 1130 { 1131 int ret = 0; 1132 1133 if (!fw_dump.fadump_enabled || fdm_active) 1134 return -EPERM; 1135 1136 mutex_lock(&fadump_mutex); 1137 1138 switch (buf[0]) { 1139 case '0': 1140 if (fw_dump.dump_registered == 0) { 1141 ret = -EINVAL; 1142 goto unlock_out; 1143 } 1144 /* Un-register Firmware-assisted dump */ 1145 fadump_unregister_dump(&fdm); 1146 break; 1147 case '1': 1148 if (fw_dump.dump_registered == 1) { 1149 ret = -EINVAL; 1150 goto unlock_out; 1151 } 1152 /* Register Firmware-assisted dump */ 1153 register_fadump(); 1154 break; 1155 default: 1156 ret = -EINVAL; 1157 break; 1158 } 1159 1160 unlock_out: 1161 mutex_unlock(&fadump_mutex); 1162 return ret < 0 ? ret : count; 1163 } 1164 1165 static int fadump_region_show(struct seq_file *m, void *private) 1166 { 1167 const struct fadump_mem_struct *fdm_ptr; 1168 1169 if (!fw_dump.fadump_enabled) 1170 return 0; 1171 1172 mutex_lock(&fadump_mutex); 1173 if (fdm_active) 1174 fdm_ptr = fdm_active; 1175 else { 1176 mutex_unlock(&fadump_mutex); 1177 fdm_ptr = &fdm; 1178 } 1179 1180 seq_printf(m, 1181 "CPU : [%#016llx-%#016llx] %#llx bytes, " 1182 "Dumped: %#llx\n", 1183 fdm_ptr->cpu_state_data.destination_address, 1184 fdm_ptr->cpu_state_data.destination_address + 1185 fdm_ptr->cpu_state_data.source_len - 1, 1186 fdm_ptr->cpu_state_data.source_len, 1187 fdm_ptr->cpu_state_data.bytes_dumped); 1188 seq_printf(m, 1189 "HPTE: [%#016llx-%#016llx] %#llx bytes, " 1190 "Dumped: %#llx\n", 1191 fdm_ptr->hpte_region.destination_address, 1192 fdm_ptr->hpte_region.destination_address + 1193 fdm_ptr->hpte_region.source_len - 1, 1194 fdm_ptr->hpte_region.source_len, 1195 fdm_ptr->hpte_region.bytes_dumped); 1196 seq_printf(m, 1197 "DUMP: [%#016llx-%#016llx] %#llx bytes, " 1198 "Dumped: %#llx\n", 1199 fdm_ptr->rmr_region.destination_address, 1200 fdm_ptr->rmr_region.destination_address + 1201 fdm_ptr->rmr_region.source_len - 1, 1202 fdm_ptr->rmr_region.source_len, 1203 fdm_ptr->rmr_region.bytes_dumped); 1204 1205 if (!fdm_active || 1206 (fw_dump.reserve_dump_area_start == 1207 fdm_ptr->cpu_state_data.destination_address)) 1208 goto out; 1209 1210 /* Dump is active. Show reserved memory region. */ 1211 seq_printf(m, 1212 " : [%#016llx-%#016llx] %#llx bytes, " 1213 "Dumped: %#llx\n", 1214 (unsigned long long)fw_dump.reserve_dump_area_start, 1215 fdm_ptr->cpu_state_data.destination_address - 1, 1216 fdm_ptr->cpu_state_data.destination_address - 1217 fw_dump.reserve_dump_area_start, 1218 fdm_ptr->cpu_state_data.destination_address - 1219 fw_dump.reserve_dump_area_start); 1220 out: 1221 if (fdm_active) 1222 mutex_unlock(&fadump_mutex); 1223 return 0; 1224 } 1225 1226 static struct kobj_attribute fadump_release_attr = __ATTR(fadump_release_mem, 1227 0200, NULL, 1228 fadump_release_memory_store); 1229 static struct kobj_attribute fadump_attr = __ATTR(fadump_enabled, 1230 0444, fadump_enabled_show, 1231 NULL); 1232 static struct kobj_attribute fadump_register_attr = __ATTR(fadump_registered, 1233 0644, fadump_register_show, 1234 fadump_register_store); 1235 1236 static int fadump_region_open(struct inode *inode, struct file *file) 1237 { 1238 return single_open(file, fadump_region_show, inode->i_private); 1239 } 1240 1241 static const struct file_operations fadump_region_fops = { 1242 .open = fadump_region_open, 1243 .read = seq_read, 1244 .llseek = seq_lseek, 1245 .release = single_release, 1246 }; 1247 1248 static void fadump_init_files(void) 1249 { 1250 struct dentry *debugfs_file; 1251 int rc = 0; 1252 1253 rc = sysfs_create_file(kernel_kobj, &fadump_attr.attr); 1254 if (rc) 1255 printk(KERN_ERR "fadump: unable to create sysfs file" 1256 " fadump_enabled (%d)\n", rc); 1257 1258 rc = sysfs_create_file(kernel_kobj, &fadump_register_attr.attr); 1259 if (rc) 1260 printk(KERN_ERR "fadump: unable to create sysfs file" 1261 " fadump_registered (%d)\n", rc); 1262 1263 debugfs_file = debugfs_create_file("fadump_region", 0444, 1264 powerpc_debugfs_root, NULL, 1265 &fadump_region_fops); 1266 if (!debugfs_file) 1267 printk(KERN_ERR "fadump: unable to create debugfs file" 1268 " fadump_region\n"); 1269 1270 if (fw_dump.dump_active) { 1271 rc = sysfs_create_file(kernel_kobj, &fadump_release_attr.attr); 1272 if (rc) 1273 printk(KERN_ERR "fadump: unable to create sysfs file" 1274 " fadump_release_mem (%d)\n", rc); 1275 } 1276 return; 1277 } 1278 1279 /* 1280 * Prepare for firmware-assisted dump. 1281 */ 1282 int __init setup_fadump(void) 1283 { 1284 if (!fw_dump.fadump_enabled) 1285 return 0; 1286 1287 if (!fw_dump.fadump_supported) { 1288 printk(KERN_ERR "Firmware-assisted dump is not supported on" 1289 " this hardware\n"); 1290 return 0; 1291 } 1292 1293 fadump_show_config(); 1294 /* 1295 * If dump data is available then see if it is valid and prepare for 1296 * saving it to the disk. 1297 */ 1298 if (fw_dump.dump_active) { 1299 /* 1300 * if dump process fails then invalidate the registration 1301 * and release memory before proceeding for re-registration. 1302 */ 1303 if (process_fadump(fdm_active) < 0) 1304 fadump_invalidate_release_mem(); 1305 } 1306 /* Initialize the kernel dump memory structure for FAD registration. */ 1307 else if (fw_dump.reserve_dump_area_size) 1308 init_fadump_mem_struct(&fdm, fw_dump.reserve_dump_area_start); 1309 fadump_init_files(); 1310 1311 return 1; 1312 } 1313 subsys_initcall(setup_fadump); 1314