xref: /linux/arch/powerpc/kernel/fadump.c (revision c0c914eca7f251c70facc37dfebeaf176601918d)
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 	const __be32 *sections;
59 	int i, num_sections;
60 	int size;
61 	const __be32 *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 1;
73 
74 	fw_dump.fadump_supported = 1;
75 	fw_dump.ibm_configure_kernel_dump = be32_to_cpu(*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 1;
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(&sections[1], 2);
106 			break;
107 		case FADUMP_HPTE_REGION:
108 			fw_dump.hpte_region_size =
109 					of_read_ulong(&sections[1], 2);
110 			break;
111 		}
112 	}
113 
114 	return 1;
115 }
116 
117 int is_fadump_active(void)
118 {
119 	return fw_dump.dump_active;
120 }
121 
122 /* Print firmware assisted dump configurations for debugging purpose. */
123 static void fadump_show_config(void)
124 {
125 	pr_debug("Support for firmware-assisted dump (fadump): %s\n",
126 			(fw_dump.fadump_supported ? "present" : "no support"));
127 
128 	if (!fw_dump.fadump_supported)
129 		return;
130 
131 	pr_debug("Fadump enabled    : %s\n",
132 				(fw_dump.fadump_enabled ? "yes" : "no"));
133 	pr_debug("Dump Active       : %s\n",
134 				(fw_dump.dump_active ? "yes" : "no"));
135 	pr_debug("Dump section sizes:\n");
136 	pr_debug("    CPU state data size: %lx\n", fw_dump.cpu_state_data_size);
137 	pr_debug("    HPTE region size   : %lx\n", fw_dump.hpte_region_size);
138 	pr_debug("Boot memory size  : %lx\n", fw_dump.boot_memory_size);
139 }
140 
141 static unsigned long init_fadump_mem_struct(struct fadump_mem_struct *fdm,
142 				unsigned long addr)
143 {
144 	if (!fdm)
145 		return 0;
146 
147 	memset(fdm, 0, sizeof(struct fadump_mem_struct));
148 	addr = addr & PAGE_MASK;
149 
150 	fdm->header.dump_format_version = cpu_to_be32(0x00000001);
151 	fdm->header.dump_num_sections = cpu_to_be16(3);
152 	fdm->header.dump_status_flag = 0;
153 	fdm->header.offset_first_dump_section =
154 		cpu_to_be32((u32)offsetof(struct fadump_mem_struct, cpu_state_data));
155 
156 	/*
157 	 * Fields for disk dump option.
158 	 * We are not using disk dump option, hence set these fields to 0.
159 	 */
160 	fdm->header.dd_block_size = 0;
161 	fdm->header.dd_block_offset = 0;
162 	fdm->header.dd_num_blocks = 0;
163 	fdm->header.dd_offset_disk_path = 0;
164 
165 	/* set 0 to disable an automatic dump-reboot. */
166 	fdm->header.max_time_auto = 0;
167 
168 	/* Kernel dump sections */
169 	/* cpu state data section. */
170 	fdm->cpu_state_data.request_flag = cpu_to_be32(FADUMP_REQUEST_FLAG);
171 	fdm->cpu_state_data.source_data_type = cpu_to_be16(FADUMP_CPU_STATE_DATA);
172 	fdm->cpu_state_data.source_address = 0;
173 	fdm->cpu_state_data.source_len = cpu_to_be64(fw_dump.cpu_state_data_size);
174 	fdm->cpu_state_data.destination_address = cpu_to_be64(addr);
175 	addr += fw_dump.cpu_state_data_size;
176 
177 	/* hpte region section */
178 	fdm->hpte_region.request_flag = cpu_to_be32(FADUMP_REQUEST_FLAG);
179 	fdm->hpte_region.source_data_type = cpu_to_be16(FADUMP_HPTE_REGION);
180 	fdm->hpte_region.source_address = 0;
181 	fdm->hpte_region.source_len = cpu_to_be64(fw_dump.hpte_region_size);
182 	fdm->hpte_region.destination_address = cpu_to_be64(addr);
183 	addr += fw_dump.hpte_region_size;
184 
185 	/* RMA region section */
186 	fdm->rmr_region.request_flag = cpu_to_be32(FADUMP_REQUEST_FLAG);
187 	fdm->rmr_region.source_data_type = cpu_to_be16(FADUMP_REAL_MODE_REGION);
188 	fdm->rmr_region.source_address = cpu_to_be64(RMA_START);
189 	fdm->rmr_region.source_len = cpu_to_be64(fw_dump.boot_memory_size);
190 	fdm->rmr_region.destination_address = cpu_to_be64(addr);
191 	addr += fw_dump.boot_memory_size;
192 
193 	return addr;
194 }
195 
196 /**
197  * fadump_calculate_reserve_size(): reserve variable boot area 5% of System RAM
198  *
199  * Function to find the largest memory size we need to reserve during early
200  * boot process. This will be the size of the memory that is required for a
201  * kernel to boot successfully.
202  *
203  * This function has been taken from phyp-assisted dump feature implementation.
204  *
205  * returns larger of 256MB or 5% rounded down to multiples of 256MB.
206  *
207  * TODO: Come up with better approach to find out more accurate memory size
208  * that is required for a kernel to boot successfully.
209  *
210  */
211 static inline unsigned long fadump_calculate_reserve_size(void)
212 {
213 	unsigned long size;
214 
215 	/*
216 	 * Check if the size is specified through fadump_reserve_mem= cmdline
217 	 * option. If yes, then use that.
218 	 */
219 	if (fw_dump.reserve_bootvar)
220 		return fw_dump.reserve_bootvar;
221 
222 	/* divide by 20 to get 5% of value */
223 	size = memblock_end_of_DRAM() / 20;
224 
225 	/* round it down in multiples of 256 */
226 	size = size & ~0x0FFFFFFFUL;
227 
228 	/* Truncate to memory_limit. We don't want to over reserve the memory.*/
229 	if (memory_limit && size > memory_limit)
230 		size = memory_limit;
231 
232 	return (size > MIN_BOOT_MEM ? size : MIN_BOOT_MEM);
233 }
234 
235 /*
236  * Calculate the total memory size required to be reserved for
237  * firmware-assisted dump registration.
238  */
239 static unsigned long get_fadump_area_size(void)
240 {
241 	unsigned long size = 0;
242 
243 	size += fw_dump.cpu_state_data_size;
244 	size += fw_dump.hpte_region_size;
245 	size += fw_dump.boot_memory_size;
246 	size += sizeof(struct fadump_crash_info_header);
247 	size += sizeof(struct elfhdr); /* ELF core header.*/
248 	size += sizeof(struct elf_phdr); /* place holder for cpu notes */
249 	/* Program headers for crash memory regions. */
250 	size += sizeof(struct elf_phdr) * (memblock_num_regions(memory) + 2);
251 
252 	size = PAGE_ALIGN(size);
253 	return size;
254 }
255 
256 int __init fadump_reserve_mem(void)
257 {
258 	unsigned long base, size, memory_boundary;
259 
260 	if (!fw_dump.fadump_enabled)
261 		return 0;
262 
263 	if (!fw_dump.fadump_supported) {
264 		printk(KERN_INFO "Firmware-assisted dump is not supported on"
265 				" this hardware\n");
266 		fw_dump.fadump_enabled = 0;
267 		return 0;
268 	}
269 	/*
270 	 * Initialize boot memory size
271 	 * If dump is active then we have already calculated the size during
272 	 * first kernel.
273 	 */
274 	if (fdm_active)
275 		fw_dump.boot_memory_size = be64_to_cpu(fdm_active->rmr_region.source_len);
276 	else
277 		fw_dump.boot_memory_size = fadump_calculate_reserve_size();
278 
279 	/*
280 	 * Calculate the memory boundary.
281 	 * If memory_limit is less than actual memory boundary then reserve
282 	 * the memory for fadump beyond the memory_limit and adjust the
283 	 * memory_limit accordingly, so that the running kernel can run with
284 	 * specified memory_limit.
285 	 */
286 	if (memory_limit && memory_limit < memblock_end_of_DRAM()) {
287 		size = get_fadump_area_size();
288 		if ((memory_limit + size) < memblock_end_of_DRAM())
289 			memory_limit += size;
290 		else
291 			memory_limit = memblock_end_of_DRAM();
292 		printk(KERN_INFO "Adjusted memory_limit for firmware-assisted"
293 				" dump, now %#016llx\n", memory_limit);
294 	}
295 	if (memory_limit)
296 		memory_boundary = memory_limit;
297 	else
298 		memory_boundary = memblock_end_of_DRAM();
299 
300 	if (fw_dump.dump_active) {
301 		printk(KERN_INFO "Firmware-assisted dump is active.\n");
302 		/*
303 		 * If last boot has crashed then reserve all the memory
304 		 * above boot_memory_size so that we don't touch it until
305 		 * dump is written to disk by userspace tool. This memory
306 		 * will be released for general use once the dump is saved.
307 		 */
308 		base = fw_dump.boot_memory_size;
309 		size = memory_boundary - base;
310 		memblock_reserve(base, size);
311 		printk(KERN_INFO "Reserved %ldMB of memory at %ldMB "
312 				"for saving crash dump\n",
313 				(unsigned long)(size >> 20),
314 				(unsigned long)(base >> 20));
315 
316 		fw_dump.fadumphdr_addr =
317 				be64_to_cpu(fdm_active->rmr_region.destination_address) +
318 				be64_to_cpu(fdm_active->rmr_region.source_len);
319 		pr_debug("fadumphdr_addr = %p\n",
320 				(void *) fw_dump.fadumphdr_addr);
321 	} else {
322 		/* Reserve the memory at the top of memory. */
323 		size = get_fadump_area_size();
324 		base = memory_boundary - size;
325 		memblock_reserve(base, size);
326 		printk(KERN_INFO "Reserved %ldMB of memory at %ldMB "
327 				"for firmware-assisted dump\n",
328 				(unsigned long)(size >> 20),
329 				(unsigned long)(base >> 20));
330 	}
331 	fw_dump.reserve_dump_area_start = base;
332 	fw_dump.reserve_dump_area_size = size;
333 	return 1;
334 }
335 
336 /* Look for fadump= cmdline option. */
337 static int __init early_fadump_param(char *p)
338 {
339 	if (!p)
340 		return 1;
341 
342 	if (strncmp(p, "on", 2) == 0)
343 		fw_dump.fadump_enabled = 1;
344 	else if (strncmp(p, "off", 3) == 0)
345 		fw_dump.fadump_enabled = 0;
346 
347 	return 0;
348 }
349 early_param("fadump", early_fadump_param);
350 
351 /* Look for fadump_reserve_mem= cmdline option */
352 static int __init early_fadump_reserve_mem(char *p)
353 {
354 	if (p)
355 		fw_dump.reserve_bootvar = memparse(p, &p);
356 	return 0;
357 }
358 early_param("fadump_reserve_mem", early_fadump_reserve_mem);
359 
360 static void register_fw_dump(struct fadump_mem_struct *fdm)
361 {
362 	int rc;
363 	unsigned int wait_time;
364 
365 	pr_debug("Registering for firmware-assisted kernel dump...\n");
366 
367 	/* TODO: Add upper time limit for the delay */
368 	do {
369 		rc = rtas_call(fw_dump.ibm_configure_kernel_dump, 3, 1, NULL,
370 			FADUMP_REGISTER, fdm,
371 			sizeof(struct fadump_mem_struct));
372 
373 		wait_time = rtas_busy_delay_time(rc);
374 		if (wait_time)
375 			mdelay(wait_time);
376 
377 	} while (wait_time);
378 
379 	switch (rc) {
380 	case -1:
381 		printk(KERN_ERR "Failed to register firmware-assisted kernel"
382 			" dump. Hardware Error(%d).\n", rc);
383 		break;
384 	case -3:
385 		printk(KERN_ERR "Failed to register firmware-assisted kernel"
386 			" dump. Parameter Error(%d).\n", rc);
387 		break;
388 	case -9:
389 		printk(KERN_ERR "firmware-assisted kernel dump is already "
390 			" registered.");
391 		fw_dump.dump_registered = 1;
392 		break;
393 	case 0:
394 		printk(KERN_INFO "firmware-assisted kernel dump registration"
395 			" is successful\n");
396 		fw_dump.dump_registered = 1;
397 		break;
398 	}
399 }
400 
401 void crash_fadump(struct pt_regs *regs, const char *str)
402 {
403 	struct fadump_crash_info_header *fdh = NULL;
404 
405 	if (!fw_dump.dump_registered || !fw_dump.fadumphdr_addr)
406 		return;
407 
408 	fdh = __va(fw_dump.fadumphdr_addr);
409 	crashing_cpu = smp_processor_id();
410 	fdh->crashing_cpu = crashing_cpu;
411 	crash_save_vmcoreinfo();
412 
413 	if (regs)
414 		fdh->regs = *regs;
415 	else
416 		ppc_save_regs(&fdh->regs);
417 
418 	fdh->online_mask = *cpu_online_mask;
419 
420 	/* Call ibm,os-term rtas call to trigger firmware assisted dump */
421 	rtas_os_term((char *)str);
422 }
423 
424 #define GPR_MASK	0xffffff0000000000
425 static inline int fadump_gpr_index(u64 id)
426 {
427 	int i = -1;
428 	char str[3];
429 
430 	if ((id & GPR_MASK) == REG_ID("GPR")) {
431 		/* get the digits at the end */
432 		id &= ~GPR_MASK;
433 		id >>= 24;
434 		str[2] = '\0';
435 		str[1] = id & 0xff;
436 		str[0] = (id >> 8) & 0xff;
437 		sscanf(str, "%d", &i);
438 		if (i > 31)
439 			i = -1;
440 	}
441 	return i;
442 }
443 
444 static inline void fadump_set_regval(struct pt_regs *regs, u64 reg_id,
445 								u64 reg_val)
446 {
447 	int i;
448 
449 	i = fadump_gpr_index(reg_id);
450 	if (i >= 0)
451 		regs->gpr[i] = (unsigned long)reg_val;
452 	else if (reg_id == REG_ID("NIA"))
453 		regs->nip = (unsigned long)reg_val;
454 	else if (reg_id == REG_ID("MSR"))
455 		regs->msr = (unsigned long)reg_val;
456 	else if (reg_id == REG_ID("CTR"))
457 		regs->ctr = (unsigned long)reg_val;
458 	else if (reg_id == REG_ID("LR"))
459 		regs->link = (unsigned long)reg_val;
460 	else if (reg_id == REG_ID("XER"))
461 		regs->xer = (unsigned long)reg_val;
462 	else if (reg_id == REG_ID("CR"))
463 		regs->ccr = (unsigned long)reg_val;
464 	else if (reg_id == REG_ID("DAR"))
465 		regs->dar = (unsigned long)reg_val;
466 	else if (reg_id == REG_ID("DSISR"))
467 		regs->dsisr = (unsigned long)reg_val;
468 }
469 
470 static struct fadump_reg_entry*
471 fadump_read_registers(struct fadump_reg_entry *reg_entry, struct pt_regs *regs)
472 {
473 	memset(regs, 0, sizeof(struct pt_regs));
474 
475 	while (be64_to_cpu(reg_entry->reg_id) != REG_ID("CPUEND")) {
476 		fadump_set_regval(regs, be64_to_cpu(reg_entry->reg_id),
477 					be64_to_cpu(reg_entry->reg_value));
478 		reg_entry++;
479 	}
480 	reg_entry++;
481 	return reg_entry;
482 }
483 
484 static u32 *fadump_append_elf_note(u32 *buf, char *name, unsigned type,
485 						void *data, size_t data_len)
486 {
487 	struct elf_note note;
488 
489 	note.n_namesz = strlen(name) + 1;
490 	note.n_descsz = data_len;
491 	note.n_type   = type;
492 	memcpy(buf, &note, sizeof(note));
493 	buf += (sizeof(note) + 3)/4;
494 	memcpy(buf, name, note.n_namesz);
495 	buf += (note.n_namesz + 3)/4;
496 	memcpy(buf, data, note.n_descsz);
497 	buf += (note.n_descsz + 3)/4;
498 
499 	return buf;
500 }
501 
502 static void fadump_final_note(u32 *buf)
503 {
504 	struct elf_note note;
505 
506 	note.n_namesz = 0;
507 	note.n_descsz = 0;
508 	note.n_type   = 0;
509 	memcpy(buf, &note, sizeof(note));
510 }
511 
512 static u32 *fadump_regs_to_elf_notes(u32 *buf, struct pt_regs *regs)
513 {
514 	struct elf_prstatus prstatus;
515 
516 	memset(&prstatus, 0, sizeof(prstatus));
517 	/*
518 	 * FIXME: How do i get PID? Do I really need it?
519 	 * prstatus.pr_pid = ????
520 	 */
521 	elf_core_copy_kernel_regs(&prstatus.pr_reg, regs);
522 	buf = fadump_append_elf_note(buf, KEXEC_CORE_NOTE_NAME, NT_PRSTATUS,
523 				&prstatus, sizeof(prstatus));
524 	return buf;
525 }
526 
527 static void fadump_update_elfcore_header(char *bufp)
528 {
529 	struct elfhdr *elf;
530 	struct elf_phdr *phdr;
531 
532 	elf = (struct elfhdr *)bufp;
533 	bufp += sizeof(struct elfhdr);
534 
535 	/* First note is a place holder for cpu notes info. */
536 	phdr = (struct elf_phdr *)bufp;
537 
538 	if (phdr->p_type == PT_NOTE) {
539 		phdr->p_paddr = fw_dump.cpu_notes_buf;
540 		phdr->p_offset	= phdr->p_paddr;
541 		phdr->p_filesz	= fw_dump.cpu_notes_buf_size;
542 		phdr->p_memsz = fw_dump.cpu_notes_buf_size;
543 	}
544 	return;
545 }
546 
547 static void *fadump_cpu_notes_buf_alloc(unsigned long size)
548 {
549 	void *vaddr;
550 	struct page *page;
551 	unsigned long order, count, i;
552 
553 	order = get_order(size);
554 	vaddr = (void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, order);
555 	if (!vaddr)
556 		return NULL;
557 
558 	count = 1 << order;
559 	page = virt_to_page(vaddr);
560 	for (i = 0; i < count; i++)
561 		SetPageReserved(page + i);
562 	return vaddr;
563 }
564 
565 static void fadump_cpu_notes_buf_free(unsigned long vaddr, unsigned long size)
566 {
567 	struct page *page;
568 	unsigned long order, count, i;
569 
570 	order = get_order(size);
571 	count = 1 << order;
572 	page = virt_to_page(vaddr);
573 	for (i = 0; i < count; i++)
574 		ClearPageReserved(page + i);
575 	__free_pages(page, order);
576 }
577 
578 /*
579  * Read CPU state dump data and convert it into ELF notes.
580  * The CPU dump starts with magic number "REGSAVE". NumCpusOffset should be
581  * used to access the data to allow for additional fields to be added without
582  * affecting compatibility. Each list of registers for a CPU starts with
583  * "CPUSTRT" and ends with "CPUEND". Each register entry is of 16 bytes,
584  * 8 Byte ASCII identifier and 8 Byte register value. The register entry
585  * with identifier "CPUSTRT" and "CPUEND" contains 4 byte cpu id as part
586  * of register value. For more details refer to PAPR document.
587  *
588  * Only for the crashing cpu we ignore the CPU dump data and get exact
589  * state from fadump crash info structure populated by first kernel at the
590  * time of crash.
591  */
592 static int __init fadump_build_cpu_notes(const struct fadump_mem_struct *fdm)
593 {
594 	struct fadump_reg_save_area_header *reg_header;
595 	struct fadump_reg_entry *reg_entry;
596 	struct fadump_crash_info_header *fdh = NULL;
597 	void *vaddr;
598 	unsigned long addr;
599 	u32 num_cpus, *note_buf;
600 	struct pt_regs regs;
601 	int i, rc = 0, cpu = 0;
602 
603 	if (!fdm->cpu_state_data.bytes_dumped)
604 		return -EINVAL;
605 
606 	addr = be64_to_cpu(fdm->cpu_state_data.destination_address);
607 	vaddr = __va(addr);
608 
609 	reg_header = vaddr;
610 	if (be64_to_cpu(reg_header->magic_number) != REGSAVE_AREA_MAGIC) {
611 		printk(KERN_ERR "Unable to read register save area.\n");
612 		return -ENOENT;
613 	}
614 	pr_debug("--------CPU State Data------------\n");
615 	pr_debug("Magic Number: %llx\n", be64_to_cpu(reg_header->magic_number));
616 	pr_debug("NumCpuOffset: %x\n", be32_to_cpu(reg_header->num_cpu_offset));
617 
618 	vaddr += be32_to_cpu(reg_header->num_cpu_offset);
619 	num_cpus = be32_to_cpu(*((__be32 *)(vaddr)));
620 	pr_debug("NumCpus     : %u\n", num_cpus);
621 	vaddr += sizeof(u32);
622 	reg_entry = (struct fadump_reg_entry *)vaddr;
623 
624 	/* Allocate buffer to hold cpu crash notes. */
625 	fw_dump.cpu_notes_buf_size = num_cpus * sizeof(note_buf_t);
626 	fw_dump.cpu_notes_buf_size = PAGE_ALIGN(fw_dump.cpu_notes_buf_size);
627 	note_buf = fadump_cpu_notes_buf_alloc(fw_dump.cpu_notes_buf_size);
628 	if (!note_buf) {
629 		printk(KERN_ERR "Failed to allocate 0x%lx bytes for "
630 			"cpu notes buffer\n", fw_dump.cpu_notes_buf_size);
631 		return -ENOMEM;
632 	}
633 	fw_dump.cpu_notes_buf = __pa(note_buf);
634 
635 	pr_debug("Allocated buffer for cpu notes of size %ld at %p\n",
636 			(num_cpus * sizeof(note_buf_t)), note_buf);
637 
638 	if (fw_dump.fadumphdr_addr)
639 		fdh = __va(fw_dump.fadumphdr_addr);
640 
641 	for (i = 0; i < num_cpus; i++) {
642 		if (be64_to_cpu(reg_entry->reg_id) != REG_ID("CPUSTRT")) {
643 			printk(KERN_ERR "Unable to read CPU state data\n");
644 			rc = -ENOENT;
645 			goto error_out;
646 		}
647 		/* Lower 4 bytes of reg_value contains logical cpu id */
648 		cpu = be64_to_cpu(reg_entry->reg_value) & FADUMP_CPU_ID_MASK;
649 		if (fdh && !cpumask_test_cpu(cpu, &fdh->online_mask)) {
650 			SKIP_TO_NEXT_CPU(reg_entry);
651 			continue;
652 		}
653 		pr_debug("Reading register data for cpu %d...\n", cpu);
654 		if (fdh && fdh->crashing_cpu == cpu) {
655 			regs = fdh->regs;
656 			note_buf = fadump_regs_to_elf_notes(note_buf, &regs);
657 			SKIP_TO_NEXT_CPU(reg_entry);
658 		} else {
659 			reg_entry++;
660 			reg_entry = fadump_read_registers(reg_entry, &regs);
661 			note_buf = fadump_regs_to_elf_notes(note_buf, &regs);
662 		}
663 	}
664 	fadump_final_note(note_buf);
665 
666 	if (fdh) {
667 		pr_debug("Updating elfcore header (%llx) with cpu notes\n",
668 							fdh->elfcorehdr_addr);
669 		fadump_update_elfcore_header((char *)__va(fdh->elfcorehdr_addr));
670 	}
671 	return 0;
672 
673 error_out:
674 	fadump_cpu_notes_buf_free((unsigned long)__va(fw_dump.cpu_notes_buf),
675 					fw_dump.cpu_notes_buf_size);
676 	fw_dump.cpu_notes_buf = 0;
677 	fw_dump.cpu_notes_buf_size = 0;
678 	return rc;
679 
680 }
681 
682 /*
683  * Validate and process the dump data stored by firmware before exporting
684  * it through '/proc/vmcore'.
685  */
686 static int __init process_fadump(const struct fadump_mem_struct *fdm_active)
687 {
688 	struct fadump_crash_info_header *fdh;
689 	int rc = 0;
690 
691 	if (!fdm_active || !fw_dump.fadumphdr_addr)
692 		return -EINVAL;
693 
694 	/* Check if the dump data is valid. */
695 	if ((be16_to_cpu(fdm_active->header.dump_status_flag) == FADUMP_ERROR_FLAG) ||
696 			(fdm_active->cpu_state_data.error_flags != 0) ||
697 			(fdm_active->rmr_region.error_flags != 0)) {
698 		printk(KERN_ERR "Dump taken by platform is not valid\n");
699 		return -EINVAL;
700 	}
701 	if ((fdm_active->rmr_region.bytes_dumped !=
702 			fdm_active->rmr_region.source_len) ||
703 			!fdm_active->cpu_state_data.bytes_dumped) {
704 		printk(KERN_ERR "Dump taken by platform is incomplete\n");
705 		return -EINVAL;
706 	}
707 
708 	/* Validate the fadump crash info header */
709 	fdh = __va(fw_dump.fadumphdr_addr);
710 	if (fdh->magic_number != FADUMP_CRASH_INFO_MAGIC) {
711 		printk(KERN_ERR "Crash info header is not valid.\n");
712 		return -EINVAL;
713 	}
714 
715 	rc = fadump_build_cpu_notes(fdm_active);
716 	if (rc)
717 		return rc;
718 
719 	/*
720 	 * We are done validating dump info and elfcore header is now ready
721 	 * to be exported. set elfcorehdr_addr so that vmcore module will
722 	 * export the elfcore header through '/proc/vmcore'.
723 	 */
724 	elfcorehdr_addr = fdh->elfcorehdr_addr;
725 
726 	return 0;
727 }
728 
729 static inline void fadump_add_crash_memory(unsigned long long base,
730 					unsigned long long end)
731 {
732 	if (base == end)
733 		return;
734 
735 	pr_debug("crash_memory_range[%d] [%#016llx-%#016llx], %#llx bytes\n",
736 		crash_mem_ranges, base, end - 1, (end - base));
737 	crash_memory_ranges[crash_mem_ranges].base = base;
738 	crash_memory_ranges[crash_mem_ranges].size = end - base;
739 	crash_mem_ranges++;
740 }
741 
742 static void fadump_exclude_reserved_area(unsigned long long start,
743 					unsigned long long end)
744 {
745 	unsigned long long ra_start, ra_end;
746 
747 	ra_start = fw_dump.reserve_dump_area_start;
748 	ra_end = ra_start + fw_dump.reserve_dump_area_size;
749 
750 	if ((ra_start < end) && (ra_end > start)) {
751 		if ((start < ra_start) && (end > ra_end)) {
752 			fadump_add_crash_memory(start, ra_start);
753 			fadump_add_crash_memory(ra_end, end);
754 		} else if (start < ra_start) {
755 			fadump_add_crash_memory(start, ra_start);
756 		} else if (ra_end < end) {
757 			fadump_add_crash_memory(ra_end, end);
758 		}
759 	} else
760 		fadump_add_crash_memory(start, end);
761 }
762 
763 static int fadump_init_elfcore_header(char *bufp)
764 {
765 	struct elfhdr *elf;
766 
767 	elf = (struct elfhdr *) bufp;
768 	bufp += sizeof(struct elfhdr);
769 	memcpy(elf->e_ident, ELFMAG, SELFMAG);
770 	elf->e_ident[EI_CLASS] = ELF_CLASS;
771 	elf->e_ident[EI_DATA] = ELF_DATA;
772 	elf->e_ident[EI_VERSION] = EV_CURRENT;
773 	elf->e_ident[EI_OSABI] = ELF_OSABI;
774 	memset(elf->e_ident+EI_PAD, 0, EI_NIDENT-EI_PAD);
775 	elf->e_type = ET_CORE;
776 	elf->e_machine = ELF_ARCH;
777 	elf->e_version = EV_CURRENT;
778 	elf->e_entry = 0;
779 	elf->e_phoff = sizeof(struct elfhdr);
780 	elf->e_shoff = 0;
781 	elf->e_flags = ELF_CORE_EFLAGS;
782 	elf->e_ehsize = sizeof(struct elfhdr);
783 	elf->e_phentsize = sizeof(struct elf_phdr);
784 	elf->e_phnum = 0;
785 	elf->e_shentsize = 0;
786 	elf->e_shnum = 0;
787 	elf->e_shstrndx = 0;
788 
789 	return 0;
790 }
791 
792 /*
793  * Traverse through memblock structure and setup crash memory ranges. These
794  * ranges will be used create PT_LOAD program headers in elfcore header.
795  */
796 static void fadump_setup_crash_memory_ranges(void)
797 {
798 	struct memblock_region *reg;
799 	unsigned long long start, end;
800 
801 	pr_debug("Setup crash memory ranges.\n");
802 	crash_mem_ranges = 0;
803 	/*
804 	 * add the first memory chunk (RMA_START through boot_memory_size) as
805 	 * a separate memory chunk. The reason is, at the time crash firmware
806 	 * will move the content of this memory chunk to different location
807 	 * specified during fadump registration. We need to create a separate
808 	 * program header for this chunk with the correct offset.
809 	 */
810 	fadump_add_crash_memory(RMA_START, fw_dump.boot_memory_size);
811 
812 	for_each_memblock(memory, reg) {
813 		start = (unsigned long long)reg->base;
814 		end = start + (unsigned long long)reg->size;
815 		if (start == RMA_START && end >= fw_dump.boot_memory_size)
816 			start = fw_dump.boot_memory_size;
817 
818 		/* add this range excluding the reserved dump area. */
819 		fadump_exclude_reserved_area(start, end);
820 	}
821 }
822 
823 /*
824  * If the given physical address falls within the boot memory region then
825  * return the relocated address that points to the dump region reserved
826  * for saving initial boot memory contents.
827  */
828 static inline unsigned long fadump_relocate(unsigned long paddr)
829 {
830 	if (paddr > RMA_START && paddr < fw_dump.boot_memory_size)
831 		return be64_to_cpu(fdm.rmr_region.destination_address) + paddr;
832 	else
833 		return paddr;
834 }
835 
836 static int fadump_create_elfcore_headers(char *bufp)
837 {
838 	struct elfhdr *elf;
839 	struct elf_phdr *phdr;
840 	int i;
841 
842 	fadump_init_elfcore_header(bufp);
843 	elf = (struct elfhdr *)bufp;
844 	bufp += sizeof(struct elfhdr);
845 
846 	/*
847 	 * setup ELF PT_NOTE, place holder for cpu notes info. The notes info
848 	 * will be populated during second kernel boot after crash. Hence
849 	 * this PT_NOTE will always be the first elf note.
850 	 *
851 	 * NOTE: Any new ELF note addition should be placed after this note.
852 	 */
853 	phdr = (struct elf_phdr *)bufp;
854 	bufp += sizeof(struct elf_phdr);
855 	phdr->p_type = PT_NOTE;
856 	phdr->p_flags = 0;
857 	phdr->p_vaddr = 0;
858 	phdr->p_align = 0;
859 
860 	phdr->p_offset = 0;
861 	phdr->p_paddr = 0;
862 	phdr->p_filesz = 0;
863 	phdr->p_memsz = 0;
864 
865 	(elf->e_phnum)++;
866 
867 	/* setup ELF PT_NOTE for vmcoreinfo */
868 	phdr = (struct elf_phdr *)bufp;
869 	bufp += sizeof(struct elf_phdr);
870 	phdr->p_type	= PT_NOTE;
871 	phdr->p_flags	= 0;
872 	phdr->p_vaddr	= 0;
873 	phdr->p_align	= 0;
874 
875 	phdr->p_paddr	= fadump_relocate(paddr_vmcoreinfo_note());
876 	phdr->p_offset	= phdr->p_paddr;
877 	phdr->p_memsz	= vmcoreinfo_max_size;
878 	phdr->p_filesz	= vmcoreinfo_max_size;
879 
880 	/* Increment number of program headers. */
881 	(elf->e_phnum)++;
882 
883 	/* setup PT_LOAD sections. */
884 
885 	for (i = 0; i < crash_mem_ranges; i++) {
886 		unsigned long long mbase, msize;
887 		mbase = crash_memory_ranges[i].base;
888 		msize = crash_memory_ranges[i].size;
889 
890 		if (!msize)
891 			continue;
892 
893 		phdr = (struct elf_phdr *)bufp;
894 		bufp += sizeof(struct elf_phdr);
895 		phdr->p_type	= PT_LOAD;
896 		phdr->p_flags	= PF_R|PF_W|PF_X;
897 		phdr->p_offset	= mbase;
898 
899 		if (mbase == RMA_START) {
900 			/*
901 			 * The entire RMA region will be moved by firmware
902 			 * to the specified destination_address. Hence set
903 			 * the correct offset.
904 			 */
905 			phdr->p_offset = be64_to_cpu(fdm.rmr_region.destination_address);
906 		}
907 
908 		phdr->p_paddr = mbase;
909 		phdr->p_vaddr = (unsigned long)__va(mbase);
910 		phdr->p_filesz = msize;
911 		phdr->p_memsz = msize;
912 		phdr->p_align = 0;
913 
914 		/* Increment number of program headers. */
915 		(elf->e_phnum)++;
916 	}
917 	return 0;
918 }
919 
920 static unsigned long init_fadump_header(unsigned long addr)
921 {
922 	struct fadump_crash_info_header *fdh;
923 
924 	if (!addr)
925 		return 0;
926 
927 	fw_dump.fadumphdr_addr = addr;
928 	fdh = __va(addr);
929 	addr += sizeof(struct fadump_crash_info_header);
930 
931 	memset(fdh, 0, sizeof(struct fadump_crash_info_header));
932 	fdh->magic_number = FADUMP_CRASH_INFO_MAGIC;
933 	fdh->elfcorehdr_addr = addr;
934 	/* We will set the crashing cpu id in crash_fadump() during crash. */
935 	fdh->crashing_cpu = CPU_UNKNOWN;
936 
937 	return addr;
938 }
939 
940 static void register_fadump(void)
941 {
942 	unsigned long addr;
943 	void *vaddr;
944 
945 	/*
946 	 * If no memory is reserved then we can not register for firmware-
947 	 * assisted dump.
948 	 */
949 	if (!fw_dump.reserve_dump_area_size)
950 		return;
951 
952 	fadump_setup_crash_memory_ranges();
953 
954 	addr = be64_to_cpu(fdm.rmr_region.destination_address) + be64_to_cpu(fdm.rmr_region.source_len);
955 	/* Initialize fadump crash info header. */
956 	addr = init_fadump_header(addr);
957 	vaddr = __va(addr);
958 
959 	pr_debug("Creating ELF core headers at %#016lx\n", addr);
960 	fadump_create_elfcore_headers(vaddr);
961 
962 	/* register the future kernel dump with firmware. */
963 	register_fw_dump(&fdm);
964 }
965 
966 static int fadump_unregister_dump(struct fadump_mem_struct *fdm)
967 {
968 	int rc = 0;
969 	unsigned int wait_time;
970 
971 	pr_debug("Un-register firmware-assisted dump\n");
972 
973 	/* TODO: Add upper time limit for the delay */
974 	do {
975 		rc = rtas_call(fw_dump.ibm_configure_kernel_dump, 3, 1, NULL,
976 			FADUMP_UNREGISTER, fdm,
977 			sizeof(struct fadump_mem_struct));
978 
979 		wait_time = rtas_busy_delay_time(rc);
980 		if (wait_time)
981 			mdelay(wait_time);
982 	} while (wait_time);
983 
984 	if (rc) {
985 		printk(KERN_ERR "Failed to un-register firmware-assisted dump."
986 			" unexpected error(%d).\n", rc);
987 		return rc;
988 	}
989 	fw_dump.dump_registered = 0;
990 	return 0;
991 }
992 
993 static int fadump_invalidate_dump(struct fadump_mem_struct *fdm)
994 {
995 	int rc = 0;
996 	unsigned int wait_time;
997 
998 	pr_debug("Invalidating firmware-assisted dump registration\n");
999 
1000 	/* TODO: Add upper time limit for the delay */
1001 	do {
1002 		rc = rtas_call(fw_dump.ibm_configure_kernel_dump, 3, 1, NULL,
1003 			FADUMP_INVALIDATE, fdm,
1004 			sizeof(struct fadump_mem_struct));
1005 
1006 		wait_time = rtas_busy_delay_time(rc);
1007 		if (wait_time)
1008 			mdelay(wait_time);
1009 	} while (wait_time);
1010 
1011 	if (rc) {
1012 		printk(KERN_ERR "Failed to invalidate firmware-assisted dump "
1013 			"rgistration. unexpected error(%d).\n", rc);
1014 		return rc;
1015 	}
1016 	fw_dump.dump_active = 0;
1017 	fdm_active = NULL;
1018 	return 0;
1019 }
1020 
1021 void fadump_cleanup(void)
1022 {
1023 	/* Invalidate the registration only if dump is active. */
1024 	if (fw_dump.dump_active) {
1025 		init_fadump_mem_struct(&fdm,
1026 			be64_to_cpu(fdm_active->cpu_state_data.destination_address));
1027 		fadump_invalidate_dump(&fdm);
1028 	}
1029 }
1030 
1031 /*
1032  * Release the memory that was reserved in early boot to preserve the memory
1033  * contents. The released memory will be available for general use.
1034  */
1035 static void fadump_release_memory(unsigned long begin, unsigned long end)
1036 {
1037 	unsigned long addr;
1038 	unsigned long ra_start, ra_end;
1039 
1040 	ra_start = fw_dump.reserve_dump_area_start;
1041 	ra_end = ra_start + fw_dump.reserve_dump_area_size;
1042 
1043 	for (addr = begin; addr < end; addr += PAGE_SIZE) {
1044 		/*
1045 		 * exclude the dump reserve area. Will reuse it for next
1046 		 * fadump registration.
1047 		 */
1048 		if (addr <= ra_end && ((addr + PAGE_SIZE) > ra_start))
1049 			continue;
1050 
1051 		free_reserved_page(pfn_to_page(addr >> PAGE_SHIFT));
1052 	}
1053 }
1054 
1055 static void fadump_invalidate_release_mem(void)
1056 {
1057 	unsigned long reserved_area_start, reserved_area_end;
1058 	unsigned long destination_address;
1059 
1060 	mutex_lock(&fadump_mutex);
1061 	if (!fw_dump.dump_active) {
1062 		mutex_unlock(&fadump_mutex);
1063 		return;
1064 	}
1065 
1066 	destination_address = be64_to_cpu(fdm_active->cpu_state_data.destination_address);
1067 	fadump_cleanup();
1068 	mutex_unlock(&fadump_mutex);
1069 
1070 	/*
1071 	 * Save the current reserved memory bounds we will require them
1072 	 * later for releasing the memory for general use.
1073 	 */
1074 	reserved_area_start = fw_dump.reserve_dump_area_start;
1075 	reserved_area_end = reserved_area_start +
1076 			fw_dump.reserve_dump_area_size;
1077 	/*
1078 	 * Setup reserve_dump_area_start and its size so that we can
1079 	 * reuse this reserved memory for Re-registration.
1080 	 */
1081 	fw_dump.reserve_dump_area_start = destination_address;
1082 	fw_dump.reserve_dump_area_size = get_fadump_area_size();
1083 
1084 	fadump_release_memory(reserved_area_start, reserved_area_end);
1085 	if (fw_dump.cpu_notes_buf) {
1086 		fadump_cpu_notes_buf_free(
1087 				(unsigned long)__va(fw_dump.cpu_notes_buf),
1088 				fw_dump.cpu_notes_buf_size);
1089 		fw_dump.cpu_notes_buf = 0;
1090 		fw_dump.cpu_notes_buf_size = 0;
1091 	}
1092 	/* Initialize the kernel dump memory structure for FAD registration. */
1093 	init_fadump_mem_struct(&fdm, fw_dump.reserve_dump_area_start);
1094 }
1095 
1096 static ssize_t fadump_release_memory_store(struct kobject *kobj,
1097 					struct kobj_attribute *attr,
1098 					const char *buf, size_t count)
1099 {
1100 	if (!fw_dump.dump_active)
1101 		return -EPERM;
1102 
1103 	if (buf[0] == '1') {
1104 		/*
1105 		 * Take away the '/proc/vmcore'. We are releasing the dump
1106 		 * memory, hence it will not be valid anymore.
1107 		 */
1108 		vmcore_cleanup();
1109 		fadump_invalidate_release_mem();
1110 
1111 	} else
1112 		return -EINVAL;
1113 	return count;
1114 }
1115 
1116 static ssize_t fadump_enabled_show(struct kobject *kobj,
1117 					struct kobj_attribute *attr,
1118 					char *buf)
1119 {
1120 	return sprintf(buf, "%d\n", fw_dump.fadump_enabled);
1121 }
1122 
1123 static ssize_t fadump_register_show(struct kobject *kobj,
1124 					struct kobj_attribute *attr,
1125 					char *buf)
1126 {
1127 	return sprintf(buf, "%d\n", fw_dump.dump_registered);
1128 }
1129 
1130 static ssize_t fadump_register_store(struct kobject *kobj,
1131 					struct kobj_attribute *attr,
1132 					const char *buf, size_t count)
1133 {
1134 	int ret = 0;
1135 
1136 	if (!fw_dump.fadump_enabled || fdm_active)
1137 		return -EPERM;
1138 
1139 	mutex_lock(&fadump_mutex);
1140 
1141 	switch (buf[0]) {
1142 	case '0':
1143 		if (fw_dump.dump_registered == 0) {
1144 			ret = -EINVAL;
1145 			goto unlock_out;
1146 		}
1147 		/* Un-register Firmware-assisted dump */
1148 		fadump_unregister_dump(&fdm);
1149 		break;
1150 	case '1':
1151 		if (fw_dump.dump_registered == 1) {
1152 			ret = -EINVAL;
1153 			goto unlock_out;
1154 		}
1155 		/* Register Firmware-assisted dump */
1156 		register_fadump();
1157 		break;
1158 	default:
1159 		ret = -EINVAL;
1160 		break;
1161 	}
1162 
1163 unlock_out:
1164 	mutex_unlock(&fadump_mutex);
1165 	return ret < 0 ? ret : count;
1166 }
1167 
1168 static int fadump_region_show(struct seq_file *m, void *private)
1169 {
1170 	const struct fadump_mem_struct *fdm_ptr;
1171 
1172 	if (!fw_dump.fadump_enabled)
1173 		return 0;
1174 
1175 	mutex_lock(&fadump_mutex);
1176 	if (fdm_active)
1177 		fdm_ptr = fdm_active;
1178 	else {
1179 		mutex_unlock(&fadump_mutex);
1180 		fdm_ptr = &fdm;
1181 	}
1182 
1183 	seq_printf(m,
1184 			"CPU : [%#016llx-%#016llx] %#llx bytes, "
1185 			"Dumped: %#llx\n",
1186 			be64_to_cpu(fdm_ptr->cpu_state_data.destination_address),
1187 			be64_to_cpu(fdm_ptr->cpu_state_data.destination_address) +
1188 			be64_to_cpu(fdm_ptr->cpu_state_data.source_len) - 1,
1189 			be64_to_cpu(fdm_ptr->cpu_state_data.source_len),
1190 			be64_to_cpu(fdm_ptr->cpu_state_data.bytes_dumped));
1191 	seq_printf(m,
1192 			"HPTE: [%#016llx-%#016llx] %#llx bytes, "
1193 			"Dumped: %#llx\n",
1194 			be64_to_cpu(fdm_ptr->hpte_region.destination_address),
1195 			be64_to_cpu(fdm_ptr->hpte_region.destination_address) +
1196 			be64_to_cpu(fdm_ptr->hpte_region.source_len) - 1,
1197 			be64_to_cpu(fdm_ptr->hpte_region.source_len),
1198 			be64_to_cpu(fdm_ptr->hpte_region.bytes_dumped));
1199 	seq_printf(m,
1200 			"DUMP: [%#016llx-%#016llx] %#llx bytes, "
1201 			"Dumped: %#llx\n",
1202 			be64_to_cpu(fdm_ptr->rmr_region.destination_address),
1203 			be64_to_cpu(fdm_ptr->rmr_region.destination_address) +
1204 			be64_to_cpu(fdm_ptr->rmr_region.source_len) - 1,
1205 			be64_to_cpu(fdm_ptr->rmr_region.source_len),
1206 			be64_to_cpu(fdm_ptr->rmr_region.bytes_dumped));
1207 
1208 	if (!fdm_active ||
1209 		(fw_dump.reserve_dump_area_start ==
1210 		be64_to_cpu(fdm_ptr->cpu_state_data.destination_address)))
1211 		goto out;
1212 
1213 	/* Dump is active. Show reserved memory region. */
1214 	seq_printf(m,
1215 			"    : [%#016llx-%#016llx] %#llx bytes, "
1216 			"Dumped: %#llx\n",
1217 			(unsigned long long)fw_dump.reserve_dump_area_start,
1218 			be64_to_cpu(fdm_ptr->cpu_state_data.destination_address) - 1,
1219 			be64_to_cpu(fdm_ptr->cpu_state_data.destination_address) -
1220 			fw_dump.reserve_dump_area_start,
1221 			be64_to_cpu(fdm_ptr->cpu_state_data.destination_address) -
1222 			fw_dump.reserve_dump_area_start);
1223 out:
1224 	if (fdm_active)
1225 		mutex_unlock(&fadump_mutex);
1226 	return 0;
1227 }
1228 
1229 static struct kobj_attribute fadump_release_attr = __ATTR(fadump_release_mem,
1230 						0200, NULL,
1231 						fadump_release_memory_store);
1232 static struct kobj_attribute fadump_attr = __ATTR(fadump_enabled,
1233 						0444, fadump_enabled_show,
1234 						NULL);
1235 static struct kobj_attribute fadump_register_attr = __ATTR(fadump_registered,
1236 						0644, fadump_register_show,
1237 						fadump_register_store);
1238 
1239 static int fadump_region_open(struct inode *inode, struct file *file)
1240 {
1241 	return single_open(file, fadump_region_show, inode->i_private);
1242 }
1243 
1244 static const struct file_operations fadump_region_fops = {
1245 	.open    = fadump_region_open,
1246 	.read    = seq_read,
1247 	.llseek  = seq_lseek,
1248 	.release = single_release,
1249 };
1250 
1251 static void fadump_init_files(void)
1252 {
1253 	struct dentry *debugfs_file;
1254 	int rc = 0;
1255 
1256 	rc = sysfs_create_file(kernel_kobj, &fadump_attr.attr);
1257 	if (rc)
1258 		printk(KERN_ERR "fadump: unable to create sysfs file"
1259 			" fadump_enabled (%d)\n", rc);
1260 
1261 	rc = sysfs_create_file(kernel_kobj, &fadump_register_attr.attr);
1262 	if (rc)
1263 		printk(KERN_ERR "fadump: unable to create sysfs file"
1264 			" fadump_registered (%d)\n", rc);
1265 
1266 	debugfs_file = debugfs_create_file("fadump_region", 0444,
1267 					powerpc_debugfs_root, NULL,
1268 					&fadump_region_fops);
1269 	if (!debugfs_file)
1270 		printk(KERN_ERR "fadump: unable to create debugfs file"
1271 				" fadump_region\n");
1272 
1273 	if (fw_dump.dump_active) {
1274 		rc = sysfs_create_file(kernel_kobj, &fadump_release_attr.attr);
1275 		if (rc)
1276 			printk(KERN_ERR "fadump: unable to create sysfs file"
1277 				" fadump_release_mem (%d)\n", rc);
1278 	}
1279 	return;
1280 }
1281 
1282 /*
1283  * Prepare for firmware-assisted dump.
1284  */
1285 int __init setup_fadump(void)
1286 {
1287 	if (!fw_dump.fadump_enabled)
1288 		return 0;
1289 
1290 	if (!fw_dump.fadump_supported) {
1291 		printk(KERN_ERR "Firmware-assisted dump is not supported on"
1292 			" this hardware\n");
1293 		return 0;
1294 	}
1295 
1296 	fadump_show_config();
1297 	/*
1298 	 * If dump data is available then see if it is valid and prepare for
1299 	 * saving it to the disk.
1300 	 */
1301 	if (fw_dump.dump_active) {
1302 		/*
1303 		 * if dump process fails then invalidate the registration
1304 		 * and release memory before proceeding for re-registration.
1305 		 */
1306 		if (process_fadump(fdm_active) < 0)
1307 			fadump_invalidate_release_mem();
1308 	}
1309 	/* Initialize the kernel dump memory structure for FAD registration. */
1310 	else if (fw_dump.reserve_dump_area_size)
1311 		init_fadump_mem_struct(&fdm, fw_dump.reserve_dump_area_start);
1312 	fadump_init_files();
1313 
1314 	return 1;
1315 }
1316 subsys_initcall(setup_fadump);
1317