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TOMOYO Linux Cross Reference
Linux/arch/powerpc/kernel/fadump.c

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  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/seq_file.h>
 34 #include <linux/crash_dump.h>
 35 #include <linux/kobject.h>
 36 #include <linux/sysfs.h>
 37 
 38 #include <asm/debugfs.h>
 39 #include <asm/page.h>
 40 #include <asm/prom.h>
 41 #include <asm/rtas.h>
 42 #include <asm/fadump.h>
 43 #include <asm/setup.h>
 44 
 45 static struct fw_dump fw_dump;
 46 static struct fadump_mem_struct fdm;
 47 static const struct fadump_mem_struct *fdm_active;
 48 
 49 static DEFINE_MUTEX(fadump_mutex);
 50 struct fad_crash_memory_ranges crash_memory_ranges[INIT_CRASHMEM_RANGES];
 51 int crash_mem_ranges;
 52 
 53 /* Scan the Firmware Assisted dump configuration details. */
 54 int __init early_init_dt_scan_fw_dump(unsigned long node,
 55                         const char *uname, int depth, void *data)
 56 {
 57         const __be32 *sections;
 58         int i, num_sections;
 59         int size;
 60         const __be32 *token;
 61 
 62         if (depth != 1 || strcmp(uname, "rtas") != 0)
 63                 return 0;
 64 
 65         /*
 66          * Check if Firmware Assisted dump is supported. if yes, check
 67          * if dump has been initiated on last reboot.
 68          */
 69         token = of_get_flat_dt_prop(node, "ibm,configure-kernel-dump", NULL);
 70         if (!token)
 71                 return 1;
 72 
 73         fw_dump.fadump_supported = 1;
 74         fw_dump.ibm_configure_kernel_dump = be32_to_cpu(*token);
 75 
 76         /*
 77          * The 'ibm,kernel-dump' rtas node is present only if there is
 78          * dump data waiting for us.
 79          */
 80         fdm_active = of_get_flat_dt_prop(node, "ibm,kernel-dump", NULL);
 81         if (fdm_active)
 82                 fw_dump.dump_active = 1;
 83 
 84         /* Get the sizes required to store dump data for the firmware provided
 85          * dump sections.
 86          * For each dump section type supported, a 32bit cell which defines
 87          * the ID of a supported section followed by two 32 bit cells which
 88          * gives teh size of the section in bytes.
 89          */
 90         sections = of_get_flat_dt_prop(node, "ibm,configure-kernel-dump-sizes",
 91                                         &size);
 92 
 93         if (!sections)
 94                 return 1;
 95 
 96         num_sections = size / (3 * sizeof(u32));
 97 
 98         for (i = 0; i < num_sections; i++, sections += 3) {
 99                 u32 type = (u32)of_read_number(sections, 1);
100 
101                 switch (type) {
102                 case FADUMP_CPU_STATE_DATA:
103                         fw_dump.cpu_state_data_size =
104                                         of_read_ulong(&sections[1], 2);
105                         break;
106                 case FADUMP_HPTE_REGION:
107                         fw_dump.hpte_region_size =
108                                         of_read_ulong(&sections[1], 2);
109                         break;
110                 }
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 = cpu_to_be32(0x00000001);
150         fdm->header.dump_num_sections = cpu_to_be16(3);
151         fdm->header.dump_status_flag = 0;
152         fdm->header.offset_first_dump_section =
153                 cpu_to_be32((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 = cpu_to_be32(FADUMP_REQUEST_FLAG);
170         fdm->cpu_state_data.source_data_type = cpu_to_be16(FADUMP_CPU_STATE_DATA);
171         fdm->cpu_state_data.source_address = 0;
172         fdm->cpu_state_data.source_len = cpu_to_be64(fw_dump.cpu_state_data_size);
173         fdm->cpu_state_data.destination_address = cpu_to_be64(addr);
174         addr += fw_dump.cpu_state_data_size;
175 
176         /* hpte region section */
177         fdm->hpte_region.request_flag = cpu_to_be32(FADUMP_REQUEST_FLAG);
178         fdm->hpte_region.source_data_type = cpu_to_be16(FADUMP_HPTE_REGION);
179         fdm->hpte_region.source_address = 0;
180         fdm->hpte_region.source_len = cpu_to_be64(fw_dump.hpte_region_size);
181         fdm->hpte_region.destination_address = cpu_to_be64(addr);
182         addr += fw_dump.hpte_region_size;
183 
184         /* RMA region section */
185         fdm->rmr_region.request_flag = cpu_to_be32(FADUMP_REQUEST_FLAG);
186         fdm->rmr_region.source_data_type = cpu_to_be16(FADUMP_REAL_MODE_REGION);
187         fdm->rmr_region.source_address = cpu_to_be64(RMA_START);
188         fdm->rmr_region.source_len = cpu_to_be64(fw_dump.boot_memory_size);
189         fdm->rmr_region.destination_address = cpu_to_be64(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         int ret;
213         unsigned long long base, size;
214 
215         /*
216          * Check if the size is specified through crashkernel= cmdline
217          * option. If yes, then use that but ignore base as fadump
218          * reserves memory at end of RAM.
219          */
220         ret = parse_crashkernel(boot_command_line, memblock_phys_mem_size(),
221                                 &size, &base);
222         if (ret == 0 && size > 0) {
223                 fw_dump.reserve_bootvar = (unsigned long)size;
224                 return fw_dump.reserve_bootvar;
225         }
226 
227         /* divide by 20 to get 5% of value */
228         size = memblock_end_of_DRAM() / 20;
229 
230         /* round it down in multiples of 256 */
231         size = size & ~0x0FFFFFFFUL;
232 
233         /* Truncate to memory_limit. We don't want to over reserve the memory.*/
234         if (memory_limit && size > memory_limit)
235                 size = memory_limit;
236 
237         return (size > MIN_BOOT_MEM ? size : MIN_BOOT_MEM);
238 }
239 
240 /*
241  * Calculate the total memory size required to be reserved for
242  * firmware-assisted dump registration.
243  */
244 static unsigned long get_fadump_area_size(void)
245 {
246         unsigned long size = 0;
247 
248         size += fw_dump.cpu_state_data_size;
249         size += fw_dump.hpte_region_size;
250         size += fw_dump.boot_memory_size;
251         size += sizeof(struct fadump_crash_info_header);
252         size += sizeof(struct elfhdr); /* ELF core header.*/
253         size += sizeof(struct elf_phdr); /* place holder for cpu notes */
254         /* Program headers for crash memory regions. */
255         size += sizeof(struct elf_phdr) * (memblock_num_regions(memory) + 2);
256 
257         size = PAGE_ALIGN(size);
258         return size;
259 }
260 
261 int __init fadump_reserve_mem(void)
262 {
263         unsigned long base, size, memory_boundary;
264 
265         if (!fw_dump.fadump_enabled)
266                 return 0;
267 
268         if (!fw_dump.fadump_supported) {
269                 printk(KERN_INFO "Firmware-assisted dump is not supported on"
270                                 " this hardware\n");
271                 fw_dump.fadump_enabled = 0;
272                 return 0;
273         }
274         /*
275          * Initialize boot memory size
276          * If dump is active then we have already calculated the size during
277          * first kernel.
278          */
279         if (fdm_active)
280                 fw_dump.boot_memory_size = be64_to_cpu(fdm_active->rmr_region.source_len);
281         else
282                 fw_dump.boot_memory_size = fadump_calculate_reserve_size();
283 
284         /*
285          * Calculate the memory boundary.
286          * If memory_limit is less than actual memory boundary then reserve
287          * the memory for fadump beyond the memory_limit and adjust the
288          * memory_limit accordingly, so that the running kernel can run with
289          * specified memory_limit.
290          */
291         if (memory_limit && memory_limit < memblock_end_of_DRAM()) {
292                 size = get_fadump_area_size();
293                 if ((memory_limit + size) < memblock_end_of_DRAM())
294                         memory_limit += size;
295                 else
296                         memory_limit = memblock_end_of_DRAM();
297                 printk(KERN_INFO "Adjusted memory_limit for firmware-assisted"
298                                 " dump, now %#016llx\n", memory_limit);
299         }
300         if (memory_limit)
301                 memory_boundary = memory_limit;
302         else
303                 memory_boundary = memblock_end_of_DRAM();
304 
305         if (fw_dump.dump_active) {
306                 printk(KERN_INFO "Firmware-assisted dump is active.\n");
307                 /*
308                  * If last boot has crashed then reserve all the memory
309                  * above boot_memory_size so that we don't touch it until
310                  * dump is written to disk by userspace tool. This memory
311                  * will be released for general use once the dump is saved.
312                  */
313                 base = fw_dump.boot_memory_size;
314                 size = memory_boundary - base;
315                 memblock_reserve(base, size);
316                 printk(KERN_INFO "Reserved %ldMB of memory at %ldMB "
317                                 "for saving crash dump\n",
318                                 (unsigned long)(size >> 20),
319                                 (unsigned long)(base >> 20));
320 
321                 fw_dump.fadumphdr_addr =
322                                 be64_to_cpu(fdm_active->rmr_region.destination_address) +
323                                 be64_to_cpu(fdm_active->rmr_region.source_len);
324                 pr_debug("fadumphdr_addr = %p\n",
325                                 (void *) fw_dump.fadumphdr_addr);
326         } else {
327                 size = get_fadump_area_size();
328 
329                 /*
330                  * Reserve memory at an offset closer to bottom of the RAM to
331                  * minimize the impact of memory hot-remove operation. We can't
332                  * use memblock_find_in_range() here since it doesn't allocate
333                  * from bottom to top.
334                  */
335                 for (base = fw_dump.boot_memory_size;
336                      base <= (memory_boundary - size);
337                      base += size) {
338                         if (memblock_is_region_memory(base, size) &&
339                             !memblock_is_region_reserved(base, size))
340                                 break;
341                 }
342                 if ((base > (memory_boundary - size)) ||
343                     memblock_reserve(base, size)) {
344                         pr_err("Failed to reserve memory\n");
345                         return 0;
346                 }
347 
348                 pr_info("Reserved %ldMB of memory at %ldMB for firmware-"
349                         "assisted dump (System RAM: %ldMB)\n",
350                         (unsigned long)(size >> 20),
351                         (unsigned long)(base >> 20),
352                         (unsigned long)(memblock_phys_mem_size() >> 20));
353         }
354 
355         fw_dump.reserve_dump_area_start = base;
356         fw_dump.reserve_dump_area_size = size;
357         return 1;
358 }
359 
360 unsigned long __init arch_reserved_kernel_pages(void)
361 {
362         return memblock_reserved_size() / PAGE_SIZE;
363 }
364 
365 /* Look for fadump= cmdline option. */
366 static int __init early_fadump_param(char *p)
367 {
368         if (!p)
369                 return 1;
370 
371         if (strncmp(p, "on", 2) == 0)
372                 fw_dump.fadump_enabled = 1;
373         else if (strncmp(p, "off", 3) == 0)
374                 fw_dump.fadump_enabled = 0;
375 
376         return 0;
377 }
378 early_param("fadump", early_fadump_param);
379 
380 static void register_fw_dump(struct fadump_mem_struct *fdm)
381 {
382         int rc;
383         unsigned int wait_time;
384 
385         pr_debug("Registering for firmware-assisted kernel dump...\n");
386 
387         /* TODO: Add upper time limit for the delay */
388         do {
389                 rc = rtas_call(fw_dump.ibm_configure_kernel_dump, 3, 1, NULL,
390                         FADUMP_REGISTER, fdm,
391                         sizeof(struct fadump_mem_struct));
392 
393                 wait_time = rtas_busy_delay_time(rc);
394                 if (wait_time)
395                         mdelay(wait_time);
396 
397         } while (wait_time);
398 
399         switch (rc) {
400         case -1:
401                 printk(KERN_ERR "Failed to register firmware-assisted kernel"
402                         " dump. Hardware Error(%d).\n", rc);
403                 break;
404         case -3:
405                 printk(KERN_ERR "Failed to register firmware-assisted kernel"
406                         " dump. Parameter Error(%d).\n", rc);
407                 break;
408         case -9:
409                 printk(KERN_ERR "firmware-assisted kernel dump is already "
410                         " registered.");
411                 fw_dump.dump_registered = 1;
412                 break;
413         case 0:
414                 printk(KERN_INFO "firmware-assisted kernel dump registration"
415                         " is successful\n");
416                 fw_dump.dump_registered = 1;
417                 break;
418         }
419 }
420 
421 void crash_fadump(struct pt_regs *regs, const char *str)
422 {
423         struct fadump_crash_info_header *fdh = NULL;
424         int old_cpu, this_cpu;
425 
426         if (!fw_dump.dump_registered || !fw_dump.fadumphdr_addr)
427                 return;
428 
429         /*
430          * old_cpu == -1 means this is the first CPU which has come here,
431          * go ahead and trigger fadump.
432          *
433          * old_cpu != -1 means some other CPU has already on it's way
434          * to trigger fadump, just keep looping here.
435          */
436         this_cpu = smp_processor_id();
437         old_cpu = cmpxchg(&crashing_cpu, -1, this_cpu);
438 
439         if (old_cpu != -1) {
440                 /*
441                  * We can't loop here indefinitely. Wait as long as fadump
442                  * is in force. If we race with fadump un-registration this
443                  * loop will break and then we go down to normal panic path
444                  * and reboot. If fadump is in force the first crashing
445                  * cpu will definitely trigger fadump.
446                  */
447                 while (fw_dump.dump_registered)
448                         cpu_relax();
449                 return;
450         }
451 
452         fdh = __va(fw_dump.fadumphdr_addr);
453         fdh->crashing_cpu = crashing_cpu;
454         crash_save_vmcoreinfo();
455 
456         if (regs)
457                 fdh->regs = *regs;
458         else
459                 ppc_save_regs(&fdh->regs);
460 
461         fdh->online_mask = *cpu_online_mask;
462 
463         /* Call ibm,os-term rtas call to trigger firmware assisted dump */
464         rtas_os_term((char *)str);
465 }
466 
467 #define GPR_MASK        0xffffff0000000000
468 static inline int fadump_gpr_index(u64 id)
469 {
470         int i = -1;
471         char str[3];
472 
473         if ((id & GPR_MASK) == REG_ID("GPR")) {
474                 /* get the digits at the end */
475                 id &= ~GPR_MASK;
476                 id >>= 24;
477                 str[2] = '\0';
478                 str[1] = id & 0xff;
479                 str[0] = (id >> 8) & 0xff;
480                 sscanf(str, "%d", &i);
481                 if (i > 31)
482                         i = -1;
483         }
484         return i;
485 }
486 
487 static inline void fadump_set_regval(struct pt_regs *regs, u64 reg_id,
488                                                                 u64 reg_val)
489 {
490         int i;
491 
492         i = fadump_gpr_index(reg_id);
493         if (i >= 0)
494                 regs->gpr[i] = (unsigned long)reg_val;
495         else if (reg_id == REG_ID("NIA"))
496                 regs->nip = (unsigned long)reg_val;
497         else if (reg_id == REG_ID("MSR"))
498                 regs->msr = (unsigned long)reg_val;
499         else if (reg_id == REG_ID("CTR"))
500                 regs->ctr = (unsigned long)reg_val;
501         else if (reg_id == REG_ID("LR"))
502                 regs->link = (unsigned long)reg_val;
503         else if (reg_id == REG_ID("XER"))
504                 regs->xer = (unsigned long)reg_val;
505         else if (reg_id == REG_ID("CR"))
506                 regs->ccr = (unsigned long)reg_val;
507         else if (reg_id == REG_ID("DAR"))
508                 regs->dar = (unsigned long)reg_val;
509         else if (reg_id == REG_ID("DSISR"))
510                 regs->dsisr = (unsigned long)reg_val;
511 }
512 
513 static struct fadump_reg_entry*
514 fadump_read_registers(struct fadump_reg_entry *reg_entry, struct pt_regs *regs)
515 {
516         memset(regs, 0, sizeof(struct pt_regs));
517 
518         while (be64_to_cpu(reg_entry->reg_id) != REG_ID("CPUEND")) {
519                 fadump_set_regval(regs, be64_to_cpu(reg_entry->reg_id),
520                                         be64_to_cpu(reg_entry->reg_value));
521                 reg_entry++;
522         }
523         reg_entry++;
524         return reg_entry;
525 }
526 
527 static u32 *fadump_regs_to_elf_notes(u32 *buf, struct pt_regs *regs)
528 {
529         struct elf_prstatus prstatus;
530 
531         memset(&prstatus, 0, sizeof(prstatus));
532         /*
533          * FIXME: How do i get PID? Do I really need it?
534          * prstatus.pr_pid = ????
535          */
536         elf_core_copy_kernel_regs(&prstatus.pr_reg, regs);
537         buf = append_elf_note(buf, CRASH_CORE_NOTE_NAME, NT_PRSTATUS,
538                               &prstatus, sizeof(prstatus));
539         return buf;
540 }
541 
542 static void fadump_update_elfcore_header(char *bufp)
543 {
544         struct elfhdr *elf;
545         struct elf_phdr *phdr;
546 
547         elf = (struct elfhdr *)bufp;
548         bufp += sizeof(struct elfhdr);
549 
550         /* First note is a place holder for cpu notes info. */
551         phdr = (struct elf_phdr *)bufp;
552 
553         if (phdr->p_type == PT_NOTE) {
554                 phdr->p_paddr = fw_dump.cpu_notes_buf;
555                 phdr->p_offset  = phdr->p_paddr;
556                 phdr->p_filesz  = fw_dump.cpu_notes_buf_size;
557                 phdr->p_memsz = fw_dump.cpu_notes_buf_size;
558         }
559         return;
560 }
561 
562 static void *fadump_cpu_notes_buf_alloc(unsigned long size)
563 {
564         void *vaddr;
565         struct page *page;
566         unsigned long order, count, i;
567 
568         order = get_order(size);
569         vaddr = (void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, order);
570         if (!vaddr)
571                 return NULL;
572 
573         count = 1 << order;
574         page = virt_to_page(vaddr);
575         for (i = 0; i < count; i++)
576                 SetPageReserved(page + i);
577         return vaddr;
578 }
579 
580 static void fadump_cpu_notes_buf_free(unsigned long vaddr, unsigned long size)
581 {
582         struct page *page;
583         unsigned long order, count, i;
584 
585         order = get_order(size);
586         count = 1 << order;
587         page = virt_to_page(vaddr);
588         for (i = 0; i < count; i++)
589                 ClearPageReserved(page + i);
590         __free_pages(page, order);
591 }
592 
593 /*
594  * Read CPU state dump data and convert it into ELF notes.
595  * The CPU dump starts with magic number "REGSAVE". NumCpusOffset should be
596  * used to access the data to allow for additional fields to be added without
597  * affecting compatibility. Each list of registers for a CPU starts with
598  * "CPUSTRT" and ends with "CPUEND". Each register entry is of 16 bytes,
599  * 8 Byte ASCII identifier and 8 Byte register value. The register entry
600  * with identifier "CPUSTRT" and "CPUEND" contains 4 byte cpu id as part
601  * of register value. For more details refer to PAPR document.
602  *
603  * Only for the crashing cpu we ignore the CPU dump data and get exact
604  * state from fadump crash info structure populated by first kernel at the
605  * time of crash.
606  */
607 static int __init fadump_build_cpu_notes(const struct fadump_mem_struct *fdm)
608 {
609         struct fadump_reg_save_area_header *reg_header;
610         struct fadump_reg_entry *reg_entry;
611         struct fadump_crash_info_header *fdh = NULL;
612         void *vaddr;
613         unsigned long addr;
614         u32 num_cpus, *note_buf;
615         struct pt_regs regs;
616         int i, rc = 0, cpu = 0;
617 
618         if (!fdm->cpu_state_data.bytes_dumped)
619                 return -EINVAL;
620 
621         addr = be64_to_cpu(fdm->cpu_state_data.destination_address);
622         vaddr = __va(addr);
623 
624         reg_header = vaddr;
625         if (be64_to_cpu(reg_header->magic_number) != REGSAVE_AREA_MAGIC) {
626                 printk(KERN_ERR "Unable to read register save area.\n");
627                 return -ENOENT;
628         }
629         pr_debug("--------CPU State Data------------\n");
630         pr_debug("Magic Number: %llx\n", be64_to_cpu(reg_header->magic_number));
631         pr_debug("NumCpuOffset: %x\n", be32_to_cpu(reg_header->num_cpu_offset));
632 
633         vaddr += be32_to_cpu(reg_header->num_cpu_offset);
634         num_cpus = be32_to_cpu(*((__be32 *)(vaddr)));
635         pr_debug("NumCpus     : %u\n", num_cpus);
636         vaddr += sizeof(u32);
637         reg_entry = (struct fadump_reg_entry *)vaddr;
638 
639         /* Allocate buffer to hold cpu crash notes. */
640         fw_dump.cpu_notes_buf_size = num_cpus * sizeof(note_buf_t);
641         fw_dump.cpu_notes_buf_size = PAGE_ALIGN(fw_dump.cpu_notes_buf_size);
642         note_buf = fadump_cpu_notes_buf_alloc(fw_dump.cpu_notes_buf_size);
643         if (!note_buf) {
644                 printk(KERN_ERR "Failed to allocate 0x%lx bytes for "
645                         "cpu notes buffer\n", fw_dump.cpu_notes_buf_size);
646                 return -ENOMEM;
647         }
648         fw_dump.cpu_notes_buf = __pa(note_buf);
649 
650         pr_debug("Allocated buffer for cpu notes of size %ld at %p\n",
651                         (num_cpus * sizeof(note_buf_t)), note_buf);
652 
653         if (fw_dump.fadumphdr_addr)
654                 fdh = __va(fw_dump.fadumphdr_addr);
655 
656         for (i = 0; i < num_cpus; i++) {
657                 if (be64_to_cpu(reg_entry->reg_id) != REG_ID("CPUSTRT")) {
658                         printk(KERN_ERR "Unable to read CPU state data\n");
659                         rc = -ENOENT;
660                         goto error_out;
661                 }
662                 /* Lower 4 bytes of reg_value contains logical cpu id */
663                 cpu = be64_to_cpu(reg_entry->reg_value) & FADUMP_CPU_ID_MASK;
664                 if (fdh && !cpumask_test_cpu(cpu, &fdh->online_mask)) {
665                         SKIP_TO_NEXT_CPU(reg_entry);
666                         continue;
667                 }
668                 pr_debug("Reading register data for cpu %d...\n", cpu);
669                 if (fdh && fdh->crashing_cpu == cpu) {
670                         regs = fdh->regs;
671                         note_buf = fadump_regs_to_elf_notes(note_buf, &regs);
672                         SKIP_TO_NEXT_CPU(reg_entry);
673                 } else {
674                         reg_entry++;
675                         reg_entry = fadump_read_registers(reg_entry, &regs);
676                         note_buf = fadump_regs_to_elf_notes(note_buf, &regs);
677                 }
678         }
679         final_note(note_buf);
680 
681         if (fdh) {
682                 pr_debug("Updating elfcore header (%llx) with cpu notes\n",
683                                                         fdh->elfcorehdr_addr);
684                 fadump_update_elfcore_header((char *)__va(fdh->elfcorehdr_addr));
685         }
686         return 0;
687 
688 error_out:
689         fadump_cpu_notes_buf_free((unsigned long)__va(fw_dump.cpu_notes_buf),
690                                         fw_dump.cpu_notes_buf_size);
691         fw_dump.cpu_notes_buf = 0;
692         fw_dump.cpu_notes_buf_size = 0;
693         return rc;
694 
695 }
696 
697 /*
698  * Validate and process the dump data stored by firmware before exporting
699  * it through '/proc/vmcore'.
700  */
701 static int __init process_fadump(const struct fadump_mem_struct *fdm_active)
702 {
703         struct fadump_crash_info_header *fdh;
704         int rc = 0;
705 
706         if (!fdm_active || !fw_dump.fadumphdr_addr)
707                 return -EINVAL;
708 
709         /* Check if the dump data is valid. */
710         if ((be16_to_cpu(fdm_active->header.dump_status_flag) == FADUMP_ERROR_FLAG) ||
711                         (fdm_active->cpu_state_data.error_flags != 0) ||
712                         (fdm_active->rmr_region.error_flags != 0)) {
713                 printk(KERN_ERR "Dump taken by platform is not valid\n");
714                 return -EINVAL;
715         }
716         if ((fdm_active->rmr_region.bytes_dumped !=
717                         fdm_active->rmr_region.source_len) ||
718                         !fdm_active->cpu_state_data.bytes_dumped) {
719                 printk(KERN_ERR "Dump taken by platform is incomplete\n");
720                 return -EINVAL;
721         }
722 
723         /* Validate the fadump crash info header */
724         fdh = __va(fw_dump.fadumphdr_addr);
725         if (fdh->magic_number != FADUMP_CRASH_INFO_MAGIC) {
726                 printk(KERN_ERR "Crash info header is not valid.\n");
727                 return -EINVAL;
728         }
729 
730         rc = fadump_build_cpu_notes(fdm_active);
731         if (rc)
732                 return rc;
733 
734         /*
735          * We are done validating dump info and elfcore header is now ready
736          * to be exported. set elfcorehdr_addr so that vmcore module will
737          * export the elfcore header through '/proc/vmcore'.
738          */
739         elfcorehdr_addr = fdh->elfcorehdr_addr;
740 
741         return 0;
742 }
743 
744 static inline void fadump_add_crash_memory(unsigned long long base,
745                                         unsigned long long end)
746 {
747         if (base == end)
748                 return;
749 
750         pr_debug("crash_memory_range[%d] [%#016llx-%#016llx], %#llx bytes\n",
751                 crash_mem_ranges, base, end - 1, (end - base));
752         crash_memory_ranges[crash_mem_ranges].base = base;
753         crash_memory_ranges[crash_mem_ranges].size = end - base;
754         crash_mem_ranges++;
755 }
756 
757 static void fadump_exclude_reserved_area(unsigned long long start,
758                                         unsigned long long end)
759 {
760         unsigned long long ra_start, ra_end;
761 
762         ra_start = fw_dump.reserve_dump_area_start;
763         ra_end = ra_start + fw_dump.reserve_dump_area_size;
764 
765         if ((ra_start < end) && (ra_end > start)) {
766                 if ((start < ra_start) && (end > ra_end)) {
767                         fadump_add_crash_memory(start, ra_start);
768                         fadump_add_crash_memory(ra_end, end);
769                 } else if (start < ra_start) {
770                         fadump_add_crash_memory(start, ra_start);
771                 } else if (ra_end < end) {
772                         fadump_add_crash_memory(ra_end, end);
773                 }
774         } else
775                 fadump_add_crash_memory(start, end);
776 }
777 
778 static int fadump_init_elfcore_header(char *bufp)
779 {
780         struct elfhdr *elf;
781 
782         elf = (struct elfhdr *) bufp;
783         bufp += sizeof(struct elfhdr);
784         memcpy(elf->e_ident, ELFMAG, SELFMAG);
785         elf->e_ident[EI_CLASS] = ELF_CLASS;
786         elf->e_ident[EI_DATA] = ELF_DATA;
787         elf->e_ident[EI_VERSION] = EV_CURRENT;
788         elf->e_ident[EI_OSABI] = ELF_OSABI;
789         memset(elf->e_ident+EI_PAD, 0, EI_NIDENT-EI_PAD);
790         elf->e_type = ET_CORE;
791         elf->e_machine = ELF_ARCH;
792         elf->e_version = EV_CURRENT;
793         elf->e_entry = 0;
794         elf->e_phoff = sizeof(struct elfhdr);
795         elf->e_shoff = 0;
796 #if defined(_CALL_ELF)
797         elf->e_flags = _CALL_ELF;
798 #else
799         elf->e_flags = 0;
800 #endif
801         elf->e_ehsize = sizeof(struct elfhdr);
802         elf->e_phentsize = sizeof(struct elf_phdr);
803         elf->e_phnum = 0;
804         elf->e_shentsize = 0;
805         elf->e_shnum = 0;
806         elf->e_shstrndx = 0;
807 
808         return 0;
809 }
810 
811 /*
812  * Traverse through memblock structure and setup crash memory ranges. These
813  * ranges will be used create PT_LOAD program headers in elfcore header.
814  */
815 static void fadump_setup_crash_memory_ranges(void)
816 {
817         struct memblock_region *reg;
818         unsigned long long start, end;
819 
820         pr_debug("Setup crash memory ranges.\n");
821         crash_mem_ranges = 0;
822         /*
823          * add the first memory chunk (RMA_START through boot_memory_size) as
824          * a separate memory chunk. The reason is, at the time crash firmware
825          * will move the content of this memory chunk to different location
826          * specified during fadump registration. We need to create a separate
827          * program header for this chunk with the correct offset.
828          */
829         fadump_add_crash_memory(RMA_START, fw_dump.boot_memory_size);
830 
831         for_each_memblock(memory, reg) {
832                 start = (unsigned long long)reg->base;
833                 end = start + (unsigned long long)reg->size;
834                 if (start == RMA_START && end >= fw_dump.boot_memory_size)
835                         start = fw_dump.boot_memory_size;
836 
837                 /* add this range excluding the reserved dump area. */
838                 fadump_exclude_reserved_area(start, end);
839         }
840 }
841 
842 /*
843  * If the given physical address falls within the boot memory region then
844  * return the relocated address that points to the dump region reserved
845  * for saving initial boot memory contents.
846  */
847 static inline unsigned long fadump_relocate(unsigned long paddr)
848 {
849         if (paddr > RMA_START && paddr < fw_dump.boot_memory_size)
850                 return be64_to_cpu(fdm.rmr_region.destination_address) + paddr;
851         else
852                 return paddr;
853 }
854 
855 static int fadump_create_elfcore_headers(char *bufp)
856 {
857         struct elfhdr *elf;
858         struct elf_phdr *phdr;
859         int i;
860 
861         fadump_init_elfcore_header(bufp);
862         elf = (struct elfhdr *)bufp;
863         bufp += sizeof(struct elfhdr);
864 
865         /*
866          * setup ELF PT_NOTE, place holder for cpu notes info. The notes info
867          * will be populated during second kernel boot after crash. Hence
868          * this PT_NOTE will always be the first elf note.
869          *
870          * NOTE: Any new ELF note addition should be placed after this note.
871          */
872         phdr = (struct elf_phdr *)bufp;
873         bufp += sizeof(struct elf_phdr);
874         phdr->p_type = PT_NOTE;
875         phdr->p_flags = 0;
876         phdr->p_vaddr = 0;
877         phdr->p_align = 0;
878 
879         phdr->p_offset = 0;
880         phdr->p_paddr = 0;
881         phdr->p_filesz = 0;
882         phdr->p_memsz = 0;
883 
884         (elf->e_phnum)++;
885 
886         /* setup ELF PT_NOTE for vmcoreinfo */
887         phdr = (struct elf_phdr *)bufp;
888         bufp += sizeof(struct elf_phdr);
889         phdr->p_type    = PT_NOTE;
890         phdr->p_flags   = 0;
891         phdr->p_vaddr   = 0;
892         phdr->p_align   = 0;
893 
894         phdr->p_paddr   = fadump_relocate(paddr_vmcoreinfo_note());
895         phdr->p_offset  = phdr->p_paddr;
896         phdr->p_memsz   = vmcoreinfo_max_size;
897         phdr->p_filesz  = vmcoreinfo_max_size;
898 
899         /* Increment number of program headers. */
900         (elf->e_phnum)++;
901 
902         /* setup PT_LOAD sections. */
903 
904         for (i = 0; i < crash_mem_ranges; i++) {
905                 unsigned long long mbase, msize;
906                 mbase = crash_memory_ranges[i].base;
907                 msize = crash_memory_ranges[i].size;
908 
909                 if (!msize)
910                         continue;
911 
912                 phdr = (struct elf_phdr *)bufp;
913                 bufp += sizeof(struct elf_phdr);
914                 phdr->p_type    = PT_LOAD;
915                 phdr->p_flags   = PF_R|PF_W|PF_X;
916                 phdr->p_offset  = mbase;
917 
918                 if (mbase == RMA_START) {
919                         /*
920                          * The entire RMA region will be moved by firmware
921                          * to the specified destination_address. Hence set
922                          * the correct offset.
923                          */
924                         phdr->p_offset = be64_to_cpu(fdm.rmr_region.destination_address);
925                 }
926 
927                 phdr->p_paddr = mbase;
928                 phdr->p_vaddr = (unsigned long)__va(mbase);
929                 phdr->p_filesz = msize;
930                 phdr->p_memsz = msize;
931                 phdr->p_align = 0;
932 
933                 /* Increment number of program headers. */
934                 (elf->e_phnum)++;
935         }
936         return 0;
937 }
938 
939 static unsigned long init_fadump_header(unsigned long addr)
940 {
941         struct fadump_crash_info_header *fdh;
942 
943         if (!addr)
944                 return 0;
945 
946         fw_dump.fadumphdr_addr = addr;
947         fdh = __va(addr);
948         addr += sizeof(struct fadump_crash_info_header);
949 
950         memset(fdh, 0, sizeof(struct fadump_crash_info_header));
951         fdh->magic_number = FADUMP_CRASH_INFO_MAGIC;
952         fdh->elfcorehdr_addr = addr;
953         /* We will set the crashing cpu id in crash_fadump() during crash. */
954         fdh->crashing_cpu = CPU_UNKNOWN;
955 
956         return addr;
957 }
958 
959 static void register_fadump(void)
960 {
961         unsigned long addr;
962         void *vaddr;
963 
964         /*
965          * If no memory is reserved then we can not register for firmware-
966          * assisted dump.
967          */
968         if (!fw_dump.reserve_dump_area_size)
969                 return;
970 
971         fadump_setup_crash_memory_ranges();
972 
973         addr = be64_to_cpu(fdm.rmr_region.destination_address) + be64_to_cpu(fdm.rmr_region.source_len);
974         /* Initialize fadump crash info header. */
975         addr = init_fadump_header(addr);
976         vaddr = __va(addr);
977 
978         pr_debug("Creating ELF core headers at %#016lx\n", addr);
979         fadump_create_elfcore_headers(vaddr);
980 
981         /* register the future kernel dump with firmware. */
982         register_fw_dump(&fdm);
983 }
984 
985 static int fadump_unregister_dump(struct fadump_mem_struct *fdm)
986 {
987         int rc = 0;
988         unsigned int wait_time;
989 
990         pr_debug("Un-register firmware-assisted dump\n");
991 
992         /* TODO: Add upper time limit for the delay */
993         do {
994                 rc = rtas_call(fw_dump.ibm_configure_kernel_dump, 3, 1, NULL,
995                         FADUMP_UNREGISTER, fdm,
996                         sizeof(struct fadump_mem_struct));
997 
998                 wait_time = rtas_busy_delay_time(rc);
999                 if (wait_time)
1000                         mdelay(wait_time);
1001         } while (wait_time);
1002 
1003         if (rc) {
1004                 printk(KERN_ERR "Failed to un-register firmware-assisted dump."
1005                         " unexpected error(%d).\n", rc);
1006                 return rc;
1007         }
1008         fw_dump.dump_registered = 0;
1009         return 0;
1010 }
1011 
1012 static int fadump_invalidate_dump(struct fadump_mem_struct *fdm)
1013 {
1014         int rc = 0;
1015         unsigned int wait_time;
1016 
1017         pr_debug("Invalidating firmware-assisted dump registration\n");
1018 
1019         /* TODO: Add upper time limit for the delay */
1020         do {
1021                 rc = rtas_call(fw_dump.ibm_configure_kernel_dump, 3, 1, NULL,
1022                         FADUMP_INVALIDATE, fdm,
1023                         sizeof(struct fadump_mem_struct));
1024 
1025                 wait_time = rtas_busy_delay_time(rc);
1026                 if (wait_time)
1027                         mdelay(wait_time);
1028         } while (wait_time);
1029 
1030         if (rc) {
1031                 pr_err("Failed to invalidate firmware-assisted dump registration. Unexpected error (%d).\n", rc);
1032                 return rc;
1033         }
1034         fw_dump.dump_active = 0;
1035         fdm_active = NULL;
1036         return 0;
1037 }
1038 
1039 void fadump_cleanup(void)
1040 {
1041         /* Invalidate the registration only if dump is active. */
1042         if (fw_dump.dump_active) {
1043                 init_fadump_mem_struct(&fdm,
1044                         be64_to_cpu(fdm_active->cpu_state_data.destination_address));
1045                 fadump_invalidate_dump(&fdm);
1046         }
1047 }
1048 
1049 /*
1050  * Release the memory that was reserved in early boot to preserve the memory
1051  * contents. The released memory will be available for general use.
1052  */
1053 static void fadump_release_memory(unsigned long begin, unsigned long end)
1054 {
1055         unsigned long addr;
1056         unsigned long ra_start, ra_end;
1057 
1058         ra_start = fw_dump.reserve_dump_area_start;
1059         ra_end = ra_start + fw_dump.reserve_dump_area_size;
1060 
1061         for (addr = begin; addr < end; addr += PAGE_SIZE) {
1062                 /*
1063                  * exclude the dump reserve area. Will reuse it for next
1064                  * fadump registration.
1065                  */
1066                 if (addr <= ra_end && ((addr + PAGE_SIZE) > ra_start))
1067                         continue;
1068 
1069                 free_reserved_page(pfn_to_page(addr >> PAGE_SHIFT));
1070         }
1071 }
1072 
1073 static void fadump_invalidate_release_mem(void)
1074 {
1075         unsigned long reserved_area_start, reserved_area_end;
1076         unsigned long destination_address;
1077 
1078         mutex_lock(&fadump_mutex);
1079         if (!fw_dump.dump_active) {
1080                 mutex_unlock(&fadump_mutex);
1081                 return;
1082         }
1083 
1084         destination_address = be64_to_cpu(fdm_active->cpu_state_data.destination_address);
1085         fadump_cleanup();
1086         mutex_unlock(&fadump_mutex);
1087 
1088         /*
1089          * Save the current reserved memory bounds we will require them
1090          * later for releasing the memory for general use.
1091          */
1092         reserved_area_start = fw_dump.reserve_dump_area_start;
1093         reserved_area_end = reserved_area_start +
1094                         fw_dump.reserve_dump_area_size;
1095         /*
1096          * Setup reserve_dump_area_start and its size so that we can
1097          * reuse this reserved memory for Re-registration.
1098          */
1099         fw_dump.reserve_dump_area_start = destination_address;
1100         fw_dump.reserve_dump_area_size = get_fadump_area_size();
1101 
1102         fadump_release_memory(reserved_area_start, reserved_area_end);
1103         if (fw_dump.cpu_notes_buf) {
1104                 fadump_cpu_notes_buf_free(
1105                                 (unsigned long)__va(fw_dump.cpu_notes_buf),
1106                                 fw_dump.cpu_notes_buf_size);
1107                 fw_dump.cpu_notes_buf = 0;
1108                 fw_dump.cpu_notes_buf_size = 0;
1109         }
1110         /* Initialize the kernel dump memory structure for FAD registration. */
1111         init_fadump_mem_struct(&fdm, fw_dump.reserve_dump_area_start);
1112 }
1113 
1114 static ssize_t fadump_release_memory_store(struct kobject *kobj,
1115                                         struct kobj_attribute *attr,
1116                                         const char *buf, size_t count)
1117 {
1118         if (!fw_dump.dump_active)
1119                 return -EPERM;
1120 
1121         if (buf[0] == '1') {
1122                 /*
1123                  * Take away the '/proc/vmcore'. We are releasing the dump
1124                  * memory, hence it will not be valid anymore.
1125                  */
1126 #ifdef CONFIG_PROC_VMCORE
1127                 vmcore_cleanup();
1128 #endif
1129                 fadump_invalidate_release_mem();
1130 
1131         } else
1132                 return -EINVAL;
1133         return count;
1134 }
1135 
1136 static ssize_t fadump_enabled_show(struct kobject *kobj,
1137                                         struct kobj_attribute *attr,
1138                                         char *buf)
1139 {
1140         return sprintf(buf, "%d\n", fw_dump.fadump_enabled);
1141 }
1142 
1143 static ssize_t fadump_register_show(struct kobject *kobj,
1144                                         struct kobj_attribute *attr,
1145                                         char *buf)
1146 {
1147         return sprintf(buf, "%d\n", fw_dump.dump_registered);
1148 }
1149 
1150 static ssize_t fadump_register_store(struct kobject *kobj,
1151                                         struct kobj_attribute *attr,
1152                                         const char *buf, size_t count)
1153 {
1154         int ret = 0;
1155 
1156         if (!fw_dump.fadump_enabled || fdm_active)
1157                 return -EPERM;
1158 
1159         mutex_lock(&fadump_mutex);
1160 
1161         switch (buf[0]) {
1162         case '':
1163                 if (fw_dump.dump_registered == 0) {
1164                         ret = -EINVAL;
1165                         goto unlock_out;
1166                 }
1167                 /* Un-register Firmware-assisted dump */
1168                 fadump_unregister_dump(&fdm);
1169                 break;
1170         case '1':
1171                 if (fw_dump.dump_registered == 1) {
1172                         ret = -EINVAL;
1173                         goto unlock_out;
1174                 }
1175                 /* Register Firmware-assisted dump */
1176                 register_fadump();
1177                 break;
1178         default:
1179                 ret = -EINVAL;
1180                 break;
1181         }
1182 
1183 unlock_out:
1184         mutex_unlock(&fadump_mutex);
1185         return ret < 0 ? ret : count;
1186 }
1187 
1188 static int fadump_region_show(struct seq_file *m, void *private)
1189 {
1190         const struct fadump_mem_struct *fdm_ptr;
1191 
1192         if (!fw_dump.fadump_enabled)
1193                 return 0;
1194 
1195         mutex_lock(&fadump_mutex);
1196         if (fdm_active)
1197                 fdm_ptr = fdm_active;
1198         else {
1199                 mutex_unlock(&fadump_mutex);
1200                 fdm_ptr = &fdm;
1201         }
1202 
1203         seq_printf(m,
1204                         "CPU : [%#016llx-%#016llx] %#llx bytes, "
1205                         "Dumped: %#llx\n",
1206                         be64_to_cpu(fdm_ptr->cpu_state_data.destination_address),
1207                         be64_to_cpu(fdm_ptr->cpu_state_data.destination_address) +
1208                         be64_to_cpu(fdm_ptr->cpu_state_data.source_len) - 1,
1209                         be64_to_cpu(fdm_ptr->cpu_state_data.source_len),
1210                         be64_to_cpu(fdm_ptr->cpu_state_data.bytes_dumped));
1211         seq_printf(m,
1212                         "HPTE: [%#016llx-%#016llx] %#llx bytes, "
1213                         "Dumped: %#llx\n",
1214                         be64_to_cpu(fdm_ptr->hpte_region.destination_address),
1215                         be64_to_cpu(fdm_ptr->hpte_region.destination_address) +
1216                         be64_to_cpu(fdm_ptr->hpte_region.source_len) - 1,
1217                         be64_to_cpu(fdm_ptr->hpte_region.source_len),
1218                         be64_to_cpu(fdm_ptr->hpte_region.bytes_dumped));
1219         seq_printf(m,
1220                         "DUMP: [%#016llx-%#016llx] %#llx bytes, "
1221                         "Dumped: %#llx\n",
1222                         be64_to_cpu(fdm_ptr->rmr_region.destination_address),
1223                         be64_to_cpu(fdm_ptr->rmr_region.destination_address) +
1224                         be64_to_cpu(fdm_ptr->rmr_region.source_len) - 1,
1225                         be64_to_cpu(fdm_ptr->rmr_region.source_len),
1226                         be64_to_cpu(fdm_ptr->rmr_region.bytes_dumped));
1227 
1228         if (!fdm_active ||
1229                 (fw_dump.reserve_dump_area_start ==
1230                 be64_to_cpu(fdm_ptr->cpu_state_data.destination_address)))
1231                 goto out;
1232 
1233         /* Dump is active. Show reserved memory region. */
1234         seq_printf(m,
1235                         "    : [%#016llx-%#016llx] %#llx bytes, "
1236                         "Dumped: %#llx\n",
1237                         (unsigned long long)fw_dump.reserve_dump_area_start,
1238                         be64_to_cpu(fdm_ptr->cpu_state_data.destination_address) - 1,
1239                         be64_to_cpu(fdm_ptr->cpu_state_data.destination_address) -
1240                         fw_dump.reserve_dump_area_start,
1241                         be64_to_cpu(fdm_ptr->cpu_state_data.destination_address) -
1242                         fw_dump.reserve_dump_area_start);
1243 out:
1244         if (fdm_active)
1245                 mutex_unlock(&fadump_mutex);
1246         return 0;
1247 }
1248 
1249 static struct kobj_attribute fadump_release_attr = __ATTR(fadump_release_mem,
1250                                                 0200, NULL,
1251                                                 fadump_release_memory_store);
1252 static struct kobj_attribute fadump_attr = __ATTR(fadump_enabled,
1253                                                 0444, fadump_enabled_show,
1254                                                 NULL);
1255 static struct kobj_attribute fadump_register_attr = __ATTR(fadump_registered,
1256                                                 0644, fadump_register_show,
1257                                                 fadump_register_store);
1258 
1259 static int fadump_region_open(struct inode *inode, struct file *file)
1260 {
1261         return single_open(file, fadump_region_show, inode->i_private);
1262 }
1263 
1264 static const struct file_operations fadump_region_fops = {
1265         .open    = fadump_region_open,
1266         .read    = seq_read,
1267         .llseek  = seq_lseek,
1268         .release = single_release,
1269 };
1270 
1271 static void fadump_init_files(void)
1272 {
1273         struct dentry *debugfs_file;
1274         int rc = 0;
1275 
1276         rc = sysfs_create_file(kernel_kobj, &fadump_attr.attr);
1277         if (rc)
1278                 printk(KERN_ERR "fadump: unable to create sysfs file"
1279                         " fadump_enabled (%d)\n", rc);
1280 
1281         rc = sysfs_create_file(kernel_kobj, &fadump_register_attr.attr);
1282         if (rc)
1283                 printk(KERN_ERR "fadump: unable to create sysfs file"
1284                         " fadump_registered (%d)\n", rc);
1285 
1286         debugfs_file = debugfs_create_file("fadump_region", 0444,
1287                                         powerpc_debugfs_root, NULL,
1288                                         &fadump_region_fops);
1289         if (!debugfs_file)
1290                 printk(KERN_ERR "fadump: unable to create debugfs file"
1291                                 " fadump_region\n");
1292 
1293         if (fw_dump.dump_active) {
1294                 rc = sysfs_create_file(kernel_kobj, &fadump_release_attr.attr);
1295                 if (rc)
1296                         printk(KERN_ERR "fadump: unable to create sysfs file"
1297                                 " fadump_release_mem (%d)\n", rc);
1298         }
1299         return;
1300 }
1301 
1302 /*
1303  * Prepare for firmware-assisted dump.
1304  */
1305 int __init setup_fadump(void)
1306 {
1307         if (!fw_dump.fadump_enabled)
1308                 return 0;
1309 
1310         if (!fw_dump.fadump_supported) {
1311                 printk(KERN_ERR "Firmware-assisted dump is not supported on"
1312                         " this hardware\n");
1313                 return 0;
1314         }
1315 
1316         fadump_show_config();
1317         /*
1318          * If dump data is available then see if it is valid and prepare for
1319          * saving it to the disk.
1320          */
1321         if (fw_dump.dump_active) {
1322                 /*
1323                  * if dump process fails then invalidate the registration
1324                  * and release memory before proceeding for re-registration.
1325                  */
1326                 if (process_fadump(fdm_active) < 0)
1327                         fadump_invalidate_release_mem();
1328         }
1329         /* Initialize the kernel dump memory structure for FAD registration. */
1330         else if (fw_dump.reserve_dump_area_size)
1331                 init_fadump_mem_struct(&fdm, fw_dump.reserve_dump_area_start);
1332         fadump_init_files();
1333 
1334         return 1;
1335 }
1336 subsys_initcall(setup_fadump);
1337 

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