1	// SPDX-License-Identifier: GPL-2.0-or-later
2	/*
3	* Firmware Assisted dump: A robust mechanism to get reliable kernel crash
4	* dump with assistance from firmware. This approach does not use kexec,
5	* instead firmware assists in booting the kdump kernel while preserving
6	* memory contents. The most of the code implementation has been adapted
7	* from phyp assisted dump implementation written by Linas Vepstas and
8	* Manish Ahuja
9	*
10	* Copyright 2011 IBM Corporation
11	* Author: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
12	*/
13
14	#undef DEBUG
15	#define pr_fmt(fmt) "fadump: " fmt
16
17	#include <linux/string.h>
18	#include <linux/memblock.h>
19	#include <linux/delay.h>
20	#include <linux/seq_file.h>
21	#include <linux/crash_dump.h>
22	#include <linux/kobject.h>
23	#include <linux/sysfs.h>
24	#include <linux/slab.h>
25	#include <linux/cma.h>
26	#include <linux/hugetlb.h>
27	#include <linux/debugfs.h>
28	#include <linux/of.h>
29	#include <linux/of_fdt.h>
30
31	#include <asm/page.h>
32	#include <asm/fadump.h>
33	#include <asm/fadump-internal.h>
34	#include <asm/setup.h>
35	#include <asm/interrupt.h>
36
37	/*
38	* The CPU who acquired the lock to trigger the fadump crash should
39	* wait for other CPUs to enter.
40	*
41	* The timeout is in milliseconds.
42	*/
43	#define CRASH_TIMEOUT 500
44
45	static struct fw_dump fw_dump;
46
47	static void __init fadump_reserve_crash_area(u64 base);
48
49	#ifndef CONFIG_PRESERVE_FA_DUMP
50
51	static struct kobject *fadump_kobj;
52
53	static atomic_t cpus_in_fadump;
54	static DEFINE_MUTEX(fadump_mutex);
55
56	static struct fadump_mrange_info crash_mrange_info = { "crash", NULL, 0, 0, 0, false };
57
58	#define RESERVED_RNGS_SZ 16384 /* 16K - 128 entries */
59	#define RESERVED_RNGS_CNT (RESERVED_RNGS_SZ / \
60	sizeof(struct fadump_memory_range))
61	static struct fadump_memory_range rngs[RESERVED_RNGS_CNT];
62	static struct fadump_mrange_info
63	reserved_mrange_info = { "reserved", rngs, RESERVED_RNGS_SZ, 0, RESERVED_RNGS_CNT, true };
64
65	static void __init early_init_dt_scan_reserved_ranges(unsigned long node);
66
67	#ifdef CONFIG_CMA
68	static struct cma *fadump_cma;
69
70	/*
71	* fadump_cma_init() - Initialize CMA area from a fadump reserved memory
72	*
73	* This function initializes CMA area from fadump reserved memory.
74	* The total size of fadump reserved memory covers for boot memory size
75	* + cpu data size + hpte size and metadata.
76	* Initialize only the area equivalent to boot memory size for CMA use.
77	* The remaining portion of fadump reserved memory will be not given
78	* to CMA and pages for those will stay reserved. boot memory size is
79	* aligned per CMA requirement to satisy cma_init_reserved_mem() call.
80	* But for some reason even if it fails we still have the memory reservation
81	* with us and we can still continue doing fadump.
82	*/
83	static int __init fadump_cma_init(void)
84	{
85	unsigned long long base, size;
86	int rc;
87
88	if (!fw_dump.fadump_enabled)
89	return 0;
90
91	/*
92	* Do not use CMA if user has provided fadump=nocma kernel parameter.
93	* Return 1 to continue with fadump old behaviour.
94	*/
95	if (fw_dump.nocma)
96	return 1;
97
98	base = fw_dump.reserve_dump_area_start;
99	size = fw_dump.boot_memory_size;
100
101	if (!size)
102	return 0;
103
104	rc = cma_init_reserved_mem(base, size, order_per_bit: 0, name: "fadump_cma", res_cma: &fadump_cma);
105	if (rc) {
106	pr_err("Failed to init cma area for firmware-assisted dump,%d\n", rc);
107	/*
108	* Though the CMA init has failed we still have memory
109	* reservation with us. The reserved memory will be
110	* blocked from production system usage. Hence return 1,
111	* so that we can continue with fadump.
112	*/
113	return 1;
114	}
115
116	/*
117	* If CMA activation fails, keep the pages reserved, instead of
118	* exposing them to buddy allocator. Same as 'fadump=nocma' case.
119	*/
120	cma_reserve_pages_on_error(cma: fadump_cma);
121
122	/*
123	* So we now have successfully initialized cma area for fadump.
124	*/
125	pr_info("Initialized 0x%lx bytes cma area at %ldMB from 0x%lx "
126	"bytes of memory reserved for firmware-assisted dump\n",
127	cma_get_size(fadump_cma),
128	(unsigned long)cma_get_base(fadump_cma) >> 20,
129	fw_dump.reserve_dump_area_size);
130	return 1;
131	}
132	#else
133	static int __init fadump_cma_init(void) { return 1; }
134	#endif /* CONFIG_CMA */
135
136	/* Scan the Firmware Assisted dump configuration details. */
137	int __init early_init_dt_scan_fw_dump(unsigned long node, const char *uname,
138	int depth, void *data)
139	{
140	if (depth == 0) {
141	early_init_dt_scan_reserved_ranges(node);
142	return 0;
143	}
144
145	if (depth != 1)
146	return 0;
147
148	if (strcmp(uname, "rtas") == 0) {
149	rtas_fadump_dt_scan(&fw_dump, node);
150	return 1;
151	}
152
153	if (strcmp(uname, "ibm,opal") == 0) {
154	opal_fadump_dt_scan(&fw_dump, node);
155	return 1;
156	}
157
158	return 0;
159	}
160
161	/*
162	* If fadump is registered, check if the memory provided
163	* falls within boot memory area and reserved memory area.
164	*/
165	int is_fadump_memory_area(u64 addr, unsigned long size)
166	{
167	u64 d_start, d_end;
168
169	if (!fw_dump.dump_registered)
170	return 0;
171
172	if (!size)
173	return 0;
174
175	d_start = fw_dump.reserve_dump_area_start;
176	d_end = d_start + fw_dump.reserve_dump_area_size;
177	if (((addr + size) > d_start) && (addr <= d_end))
178	return 1;
179
180	return (addr <= fw_dump.boot_mem_top);
181	}
182
183	int should_fadump_crash(void)
184	{
185	if (!fw_dump.dump_registered || !fw_dump.fadumphdr_addr)
186	return 0;
187	return 1;
188	}
189
190	int is_fadump_active(void)
191	{
192	return fw_dump.dump_active;
193	}
194
195	/*
196	* Returns true, if there are no holes in memory area between d_start to d_end,
197	* false otherwise.
198	*/
199	static bool is_fadump_mem_area_contiguous(u64 d_start, u64 d_end)
200	{
201	phys_addr_t reg_start, reg_end;
202	bool ret = false;
203	u64 i, start, end;
204
205	for_each_mem_range(i, &reg_start, &reg_end) {
206	start = max_t(u64, d_start, reg_start);
207	end = min_t(u64, d_end, reg_end);
208	if (d_start < end) {
209	/* Memory hole from d_start to start */
210	if (start > d_start)
211	break;
212
213	if (end == d_end) {
214	ret = true;
215	break;
216	}
217
218	d_start = end + 1;
219	}
220	}
221
222	return ret;
223	}
224
225	/*
226	* Returns true, if there are no holes in boot memory area,
227	* false otherwise.
228	*/
229	bool is_fadump_boot_mem_contiguous(void)
230	{
231	unsigned long d_start, d_end;
232	bool ret = false;
233	int i;
234
235	for (i = 0; i < fw_dump.boot_mem_regs_cnt; i++) {
236	d_start = fw_dump.boot_mem_addr[i];
237	d_end = d_start + fw_dump.boot_mem_sz[i];
238
239	ret = is_fadump_mem_area_contiguous(d_start, d_end);
240	if (!ret)
241	break;
242	}
243
244	return ret;
245	}
246
247	/*
248	* Returns true, if there are no holes in reserved memory area,
249	* false otherwise.
250	*/
251	bool is_fadump_reserved_mem_contiguous(void)
252	{
253	u64 d_start, d_end;
254
255	d_start = fw_dump.reserve_dump_area_start;
256	d_end = d_start + fw_dump.reserve_dump_area_size;
257	return is_fadump_mem_area_contiguous(d_start, d_end);
258	}
259
260	/* Print firmware assisted dump configurations for debugging purpose. */
261	static void __init fadump_show_config(void)
262	{
263	int i;
264
265	pr_debug("Support for firmware-assisted dump (fadump): %s\n",
266	(fw_dump.fadump_supported ? "present" : "no support"));
267
268	if (!fw_dump.fadump_supported)
269	return;
270
271	pr_debug("Fadump enabled : %s\n",
272	(fw_dump.fadump_enabled ? "yes" : "no"));
273	pr_debug("Dump Active : %s\n",
274	(fw_dump.dump_active ? "yes" : "no"));
275	pr_debug("Dump section sizes:\n");
276	pr_debug(" CPU state data size: %lx\n", fw_dump.cpu_state_data_size);
277	pr_debug(" HPTE region size : %lx\n", fw_dump.hpte_region_size);
278	pr_debug(" Boot memory size : %lx\n", fw_dump.boot_memory_size);
279	pr_debug(" Boot memory top : %llx\n", fw_dump.boot_mem_top);
280	pr_debug("Boot memory regions cnt: %llx\n", fw_dump.boot_mem_regs_cnt);
281	for (i = 0; i < fw_dump.boot_mem_regs_cnt; i++) {
282	pr_debug("[%03d] base = %llx, size = %llx\n", i,
283	fw_dump.boot_mem_addr[i], fw_dump.boot_mem_sz[i]);
284	}
285	}
286
287	/**
288	* fadump_calculate_reserve_size(): reserve variable boot area 5% of System RAM
289	*
290	* Function to find the largest memory size we need to reserve during early
291	* boot process. This will be the size of the memory that is required for a
292	* kernel to boot successfully.
293	*
294	* This function has been taken from phyp-assisted dump feature implementation.
295	*
296	* returns larger of 256MB or 5% rounded down to multiples of 256MB.
297	*
298	* TODO: Come up with better approach to find out more accurate memory size
299	* that is required for a kernel to boot successfully.
300	*
301	*/
302	static __init u64 fadump_calculate_reserve_size(void)
303	{
304	u64 base, size, bootmem_min;
305	int ret;
306
307	if (fw_dump.reserve_bootvar)
308	pr_warn("'fadump_reserve_mem=' parameter is deprecated in favor of 'crashkernel=' parameter.\n");
309
310	/*
311	* Check if the size is specified through crashkernel= cmdline
312	* option. If yes, then use that but ignore base as fadump reserves
313	* memory at a predefined offset.
314	*/
315	ret = parse_crashkernel(cmdline: boot_command_line, system_ram: memblock_phys_mem_size(),
316	crash_size: &size, crash_base: &base, NULL, NULL);
317	if (ret == 0 && size > 0) {
318	unsigned long max_size;
319
320	if (fw_dump.reserve_bootvar)
321	pr_info("Using 'crashkernel=' parameter for memory reservation.\n");
322
323	fw_dump.reserve_bootvar = (unsigned long)size;
324
325	/*
326	* Adjust if the boot memory size specified is above
327	* the upper limit.
328	*/
329	max_size = memblock_phys_mem_size() / MAX_BOOT_MEM_RATIO;
330	if (fw_dump.reserve_bootvar > max_size) {
331	fw_dump.reserve_bootvar = max_size;
332	pr_info("Adjusted boot memory size to %luMB\n",
333	(fw_dump.reserve_bootvar >> 20));
334	}
335
336	return fw_dump.reserve_bootvar;
337	} else if (fw_dump.reserve_bootvar) {
338	/*
339	* 'fadump_reserve_mem=' is being used to reserve memory
340	* for firmware-assisted dump.
341	*/
342	return fw_dump.reserve_bootvar;
343	}
344
345	/* divide by 20 to get 5% of value */
346	size = memblock_phys_mem_size() / 20;
347
348	/* round it down in multiples of 256 */
349	size = size & ~0x0FFFFFFFUL;
350
351	/* Truncate to memory_limit. We don't want to over reserve the memory.*/
352	if (memory_limit && size > memory_limit)
353	size = memory_limit;
354
355	bootmem_min = fw_dump.ops->fadump_get_bootmem_min();
356	return (size > bootmem_min ? size : bootmem_min);
357	}
358
359	/*
360	* Calculate the total memory size required to be reserved for
361	* firmware-assisted dump registration.
362	*/
363	static unsigned long __init get_fadump_area_size(void)
364	{
365	unsigned long size = 0;
366
367	size += fw_dump.cpu_state_data_size;
368	size += fw_dump.hpte_region_size;
369	/*
370	* Account for pagesize alignment of boot memory area destination address.
371	* This faciliates in mmap reading of first kernel's memory.
372	*/
373	size = PAGE_ALIGN(size);
374	size += fw_dump.boot_memory_size;
375	size += sizeof(struct fadump_crash_info_header);
376	size += sizeof(struct elfhdr); /* ELF core header.*/
377	size += sizeof(struct elf_phdr); /* place holder for cpu notes */
378	/* Program headers for crash memory regions. */
379	size += sizeof(struct elf_phdr) * (memblock_num_regions(memory) + 2);
380
381	size = PAGE_ALIGN(size);
382
383	/* This is to hold kernel metadata on platforms that support it */
384	size += (fw_dump.ops->fadump_get_metadata_size ?
385	fw_dump.ops->fadump_get_metadata_size() : 0);
386	return size;
387	}
388
389	static int __init add_boot_mem_region(unsigned long rstart,
390	unsigned long rsize)
391	{
392	int i = fw_dump.boot_mem_regs_cnt++;
393
394	if (fw_dump.boot_mem_regs_cnt > FADUMP_MAX_MEM_REGS) {
395	fw_dump.boot_mem_regs_cnt = FADUMP_MAX_MEM_REGS;
396	return 0;
397	}
398
399	pr_debug("Added boot memory range[%d] [%#016lx-%#016lx)\n",
400	i, rstart, (rstart + rsize));
401	fw_dump.boot_mem_addr[i] = rstart;
402	fw_dump.boot_mem_sz[i] = rsize;
403	return 1;
404	}
405
406	/*
407	* Firmware usually has a hard limit on the data it can copy per region.
408	* Honour that by splitting a memory range into multiple regions.
409	*/
410	static int __init add_boot_mem_regions(unsigned long mstart,
411	unsigned long msize)
412	{
413	unsigned long rstart, rsize, max_size;
414	int ret = 1;
415
416	rstart = mstart;
417	max_size = fw_dump.max_copy_size ? fw_dump.max_copy_size : msize;
418	while (msize) {
419	if (msize > max_size)
420	rsize = max_size;
421	else
422	rsize = msize;
423
424	ret = add_boot_mem_region(rstart, rsize);
425	if (!ret)
426	break;
427
428	msize -= rsize;
429	rstart += rsize;
430	}
431
432	return ret;
433	}
434
435	static int __init fadump_get_boot_mem_regions(void)
436	{
437	unsigned long size, cur_size, hole_size, last_end;
438	unsigned long mem_size = fw_dump.boot_memory_size;
439	phys_addr_t reg_start, reg_end;
440	int ret = 1;
441	u64 i;
442
443	fw_dump.boot_mem_regs_cnt = 0;
444
445	last_end = 0;
446	hole_size = 0;
447	cur_size = 0;
448	for_each_mem_range(i, &reg_start, &reg_end) {
449	size = reg_end - reg_start;
450	hole_size += (reg_start - last_end);
451
452	if ((cur_size + size) >= mem_size) {
453	size = (mem_size - cur_size);
454	ret = add_boot_mem_regions(mstart: reg_start, msize: size);
455	break;
456	}
457
458	mem_size -= size;
459	cur_size += size;
460	ret = add_boot_mem_regions(mstart: reg_start, msize: size);
461	if (!ret)
462	break;
463
464	last_end = reg_end;
465	}
466	fw_dump.boot_mem_top = PAGE_ALIGN(fw_dump.boot_memory_size + hole_size);
467
468	return ret;
469	}
470
471	/*
472	* Returns true, if the given range overlaps with reserved memory ranges
473	* starting at idx. Also, updates idx to index of overlapping memory range
474	* with the given memory range.
475	* False, otherwise.
476	*/
477	static bool __init overlaps_reserved_ranges(u64 base, u64 end, int *idx)
478	{
479	bool ret = false;
480	int i;
481
482	for (i = *idx; i < reserved_mrange_info.mem_range_cnt; i++) {
483	u64 rbase = reserved_mrange_info.mem_ranges[i].base;
484	u64 rend = rbase + reserved_mrange_info.mem_ranges[i].size;
485
486	if (end <= rbase)
487	break;
488
489	if ((end > rbase) && (base < rend)) {
490	*idx = i;
491	ret = true;
492	break;
493	}
494	}
495
496	return ret;
497	}
498
499	/*
500	* Locate a suitable memory area to reserve memory for FADump. While at it,
501	* lookup reserved-ranges & avoid overlap with them, as they are used by F/W.
502	*/
503	static u64 __init fadump_locate_reserve_mem(u64 base, u64 size)
504	{
505	struct fadump_memory_range *mrngs;
506	phys_addr_t mstart, mend;
507	int idx = 0;
508	u64 i, ret = 0;
509
510	mrngs = reserved_mrange_info.mem_ranges;
511	for_each_free_mem_range(i, NUMA_NO_NODE, MEMBLOCK_NONE,
512	&mstart, &mend, NULL) {
513	pr_debug("%llu) mstart: %llx, mend: %llx, base: %llx\n",
514	i, mstart, mend, base);
515
516	if (mstart > base)
517	base = PAGE_ALIGN(mstart);
518
519	while ((mend > base) && ((mend - base) >= size)) {
520	if (!overlaps_reserved_ranges(base, end: base+size, idx: &idx)) {
521	ret = base;
522	goto out;
523	}
524
525	base = mrngs[idx].base + mrngs[idx].size;
526	base = PAGE_ALIGN(base);
527	}
528	}
529
530	out:
531	return ret;
532	}
533
534	int __init fadump_reserve_mem(void)
535	{
536	u64 base, size, mem_boundary, bootmem_min;
537	int ret = 1;
538
539	if (!fw_dump.fadump_enabled)
540	return 0;
541
542	if (!fw_dump.fadump_supported) {
543	pr_info("Firmware-Assisted Dump is not supported on this hardware\n");
544	goto error_out;
545	}
546
547	/*
548	* Initialize boot memory size
549	* If dump is active then we have already calculated the size during
550	* first kernel.
551	*/
552	if (!fw_dump.dump_active) {
553	fw_dump.boot_memory_size =
554	PAGE_ALIGN(fadump_calculate_reserve_size());
555	#ifdef CONFIG_CMA
556	if (!fw_dump.nocma) {
557	fw_dump.boot_memory_size =
558	ALIGN(fw_dump.boot_memory_size,
559	CMA_MIN_ALIGNMENT_BYTES);
560	}
561	#endif
562
563	bootmem_min = fw_dump.ops->fadump_get_bootmem_min();
564	if (fw_dump.boot_memory_size < bootmem_min) {
565	pr_err("Can't enable fadump with boot memory size (0x%lx) less than 0x%llx\n",
566	fw_dump.boot_memory_size, bootmem_min);
567	goto error_out;
568	}
569
570	if (!fadump_get_boot_mem_regions()) {
571	pr_err("Too many holes in boot memory area to enable fadump\n");
572	goto error_out;
573	}
574	}
575
576	/*
577	* Calculate the memory boundary.
578	* If memory_limit is less than actual memory boundary then reserve
579	* the memory for fadump beyond the memory_limit and adjust the
580	* memory_limit accordingly, so that the running kernel can run with
581	* specified memory_limit.
582	*/
583	if (memory_limit && memory_limit < memblock_end_of_DRAM()) {
584	size = get_fadump_area_size();
585	if ((memory_limit + size) < memblock_end_of_DRAM())
586	memory_limit += size;
587	else
588	memory_limit = memblock_end_of_DRAM();
589	printk(KERN_INFO "Adjusted memory_limit for firmware-assisted"
590	" dump, now %#016llx\n", memory_limit);
591	}
592	if (memory_limit)
593	mem_boundary = memory_limit;
594	else
595	mem_boundary = memblock_end_of_DRAM();
596
597	base = fw_dump.boot_mem_top;
598	size = get_fadump_area_size();
599	fw_dump.reserve_dump_area_size = size;
600	if (fw_dump.dump_active) {
601	pr_info("Firmware-assisted dump is active.\n");
602
603	#ifdef CONFIG_HUGETLB_PAGE
604	/*
605	* FADump capture kernel doesn't care much about hugepages.
606	* In fact, handling hugepages in capture kernel is asking for
607	* trouble. So, disable HugeTLB support when fadump is active.
608	*/
609	hugetlb_disabled = true;
610	#endif
611	/*
612	* If last boot has crashed then reserve all the memory
613	* above boot memory size so that we don't touch it until
614	* dump is written to disk by userspace tool. This memory
615	* can be released for general use by invalidating fadump.
616	*/
617	fadump_reserve_crash_area(base);
618
619	pr_debug("fadumphdr_addr = %#016lx\n", fw_dump.fadumphdr_addr);
620	pr_debug("Reserve dump area start address: 0x%lx\n",
621	fw_dump.reserve_dump_area_start);
622	} else {
623	/*
624	* Reserve memory at an offset closer to bottom of the RAM to
625	* minimize the impact of memory hot-remove operation.
626	*/
627	base = fadump_locate_reserve_mem(base, size);
628
629	if (!base || (base + size > mem_boundary)) {
630	pr_err("Failed to find memory chunk for reservation!\n");
631	goto error_out;
632	}
633	fw_dump.reserve_dump_area_start = base;
634
635	/*
636	* Calculate the kernel metadata address and register it with
637	* f/w if the platform supports.
638	*/
639	if (fw_dump.ops->fadump_setup_metadata &&
640	(fw_dump.ops->fadump_setup_metadata(&fw_dump) < 0))
641	goto error_out;
642
643	if (memblock_reserve(base, size)) {
644	pr_err("Failed to reserve memory!\n");
645	goto error_out;
646	}
647
648	pr_info("Reserved %lldMB of memory at %#016llx (System RAM: %lldMB)\n",
649	(size >> 20), base, (memblock_phys_mem_size() >> 20));
650
651	ret = fadump_cma_init();
652	}
653
654	return ret;
655	error_out:
656	fw_dump.fadump_enabled = 0;
657	fw_dump.reserve_dump_area_size = 0;
658	return 0;
659	}
660
661	/* Look for fadump= cmdline option. */
662	static int __init early_fadump_param(char *p)
663	{
664	if (!p)
665	return 1;
666
667	if (strncmp(p, "on", 2) == 0)
668	fw_dump.fadump_enabled = 1;
669	else if (strncmp(p, "off", 3) == 0)
670	fw_dump.fadump_enabled = 0;
671	else if (strncmp(p, "nocma", 5) == 0) {
672	fw_dump.fadump_enabled = 1;
673	fw_dump.nocma = 1;
674	}
675
676	return 0;
677	}
678	early_param("fadump", early_fadump_param);
679
680	/*
681	* Look for fadump_reserve_mem= cmdline option
682	* TODO: Remove references to 'fadump_reserve_mem=' parameter,
683	* the sooner 'crashkernel=' parameter is accustomed to.
684	*/
685	static int __init early_fadump_reserve_mem(char *p)
686	{
687	if (p)
688	fw_dump.reserve_bootvar = memparse(ptr: p, retptr: &p);
689	return 0;
690	}
691	early_param("fadump_reserve_mem", early_fadump_reserve_mem);
692
693	void crash_fadump(struct pt_regs *regs, const char *str)
694	{
695	unsigned int msecs;
696	struct fadump_crash_info_header *fdh = NULL;
697	int old_cpu, this_cpu;
698	/* Do not include first CPU */
699	unsigned int ncpus = num_online_cpus() - 1;
700
701	if (!should_fadump_crash())
702	return;
703
704	/*
705	* old_cpu == -1 means this is the first CPU which has come here,
706	* go ahead and trigger fadump.
707	*
708	* old_cpu != -1 means some other CPU has already on it's way
709	* to trigger fadump, just keep looping here.
710	*/
711	this_cpu = smp_processor_id();
712	old_cpu = cmpxchg(&crashing_cpu, -1, this_cpu);
713
714	if (old_cpu != -1) {
715	atomic_inc(v: &cpus_in_fadump);
716
717	/*
718	* We can't loop here indefinitely. Wait as long as fadump
719	* is in force. If we race with fadump un-registration this
720	* loop will break and then we go down to normal panic path
721	* and reboot. If fadump is in force the first crashing
722	* cpu will definitely trigger fadump.
723	*/
724	while (fw_dump.dump_registered)
725	cpu_relax();
726	return;
727	}
728
729	fdh = __va(fw_dump.fadumphdr_addr);
730	fdh->crashing_cpu = crashing_cpu;
731	crash_save_vmcoreinfo();
732
733	if (regs)
734	fdh->regs = *regs;
735	else
736	ppc_save_regs(&fdh->regs);
737
738	fdh->cpu_mask = *cpu_online_mask;
739
740	/*
741	* If we came in via system reset, wait a while for the secondary
742	* CPUs to enter.
743	*/
744	if (TRAP(&(fdh->regs)) == INTERRUPT_SYSTEM_RESET) {
745	msecs = CRASH_TIMEOUT;
746	while ((atomic_read(v: &cpus_in_fadump) < ncpus) && (--msecs > 0))
747	mdelay(1);
748	}
749
750	fw_dump.ops->fadump_trigger(fdh, str);
751	}
752
753	u32 *__init fadump_regs_to_elf_notes(u32 *buf, struct pt_regs *regs)
754	{
755	struct elf_prstatus prstatus;
756
757	memset(&prstatus, 0, sizeof(prstatus));
758	/*
759	* FIXME: How do i get PID? Do I really need it?
760	* prstatus.pr_pid = ????
761	*/
762	elf_core_copy_regs(elfregs: &prstatus.pr_reg, regs);
763	buf = append_elf_note(buf, CRASH_CORE_NOTE_NAME, NT_PRSTATUS,
764	data: &prstatus, data_len: sizeof(prstatus));
765	return buf;
766	}
767
768	void __init fadump_update_elfcore_header(char *bufp)
769	{
770	struct elf_phdr *phdr;
771
772	bufp += sizeof(struct elfhdr);
773
774	/* First note is a place holder for cpu notes info. */
775	phdr = (struct elf_phdr *)bufp;
776
777	if (phdr->p_type == PT_NOTE) {
778	phdr->p_paddr = __pa(fw_dump.cpu_notes_buf_vaddr);
779	phdr->p_offset = phdr->p_paddr;
780	phdr->p_filesz = fw_dump.cpu_notes_buf_size;
781	phdr->p_memsz = fw_dump.cpu_notes_buf_size;
782	}
783	return;
784	}
785
786	static void *__init fadump_alloc_buffer(unsigned long size)
787	{
788	unsigned long count, i;
789	struct page *page;
790	void *vaddr;
791
792	vaddr = alloc_pages_exact(size, GFP_KERNEL | __GFP_ZERO);
793	if (!vaddr)
794	return NULL;
795
796	count = PAGE_ALIGN(size) / PAGE_SIZE;
797	page = virt_to_page(vaddr);
798	for (i = 0; i < count; i++)
799	mark_page_reserved(page: page + i);
800	return vaddr;
801	}
802
803	static void fadump_free_buffer(unsigned long vaddr, unsigned long size)
804	{
805	free_reserved_area(start: (void *)vaddr, end: (void *)(vaddr + size), poison: -1, NULL);
806	}
807
808	s32 __init fadump_setup_cpu_notes_buf(u32 num_cpus)
809	{
810	/* Allocate buffer to hold cpu crash notes. */
811	fw_dump.cpu_notes_buf_size = num_cpus * sizeof(note_buf_t);
812	fw_dump.cpu_notes_buf_size = PAGE_ALIGN(fw_dump.cpu_notes_buf_size);
813	fw_dump.cpu_notes_buf_vaddr =
814	(unsigned long)fadump_alloc_buffer(size: fw_dump.cpu_notes_buf_size);
815	if (!fw_dump.cpu_notes_buf_vaddr) {
816	pr_err("Failed to allocate %ld bytes for CPU notes buffer\n",
817	fw_dump.cpu_notes_buf_size);
818	return -ENOMEM;
819	}
820
821	pr_debug("Allocated buffer for cpu notes of size %ld at 0x%lx\n",
822	fw_dump.cpu_notes_buf_size,
823	fw_dump.cpu_notes_buf_vaddr);
824	return 0;
825	}
826
827	void fadump_free_cpu_notes_buf(void)
828	{
829	if (!fw_dump.cpu_notes_buf_vaddr)
830	return;
831
832	fadump_free_buffer(vaddr: fw_dump.cpu_notes_buf_vaddr,
833	size: fw_dump.cpu_notes_buf_size);
834	fw_dump.cpu_notes_buf_vaddr = 0;
835	fw_dump.cpu_notes_buf_size = 0;
836	}
837
838	static void fadump_free_mem_ranges(struct fadump_mrange_info *mrange_info)
839	{
840	if (mrange_info->is_static) {
841	mrange_info->mem_range_cnt = 0;
842	return;
843	}
844
845	kfree(objp: mrange_info->mem_ranges);
846	memset((void *)((u64)mrange_info + RNG_NAME_SZ), 0,
847	(sizeof(struct fadump_mrange_info) - RNG_NAME_SZ));
848	}
849
850	/*
851	* Allocate or reallocate mem_ranges array in incremental units
852	* of PAGE_SIZE.
853	*/
854	static int fadump_alloc_mem_ranges(struct fadump_mrange_info *mrange_info)
855	{
856	struct fadump_memory_range *new_array;
857	u64 new_size;
858
859	new_size = mrange_info->mem_ranges_sz + PAGE_SIZE;
860	pr_debug("Allocating %llu bytes of memory for %s memory ranges\n",
861	new_size, mrange_info->name);
862
863	new_array = krealloc(objp: mrange_info->mem_ranges, new_size, GFP_KERNEL);
864	if (new_array == NULL) {
865	pr_err("Insufficient memory for setting up %s memory ranges\n",
866	mrange_info->name);
867	fadump_free_mem_ranges(mrange_info);
868	return -ENOMEM;
869	}
870
871	mrange_info->mem_ranges = new_array;
872	mrange_info->mem_ranges_sz = new_size;
873	mrange_info->max_mem_ranges = (new_size /
874	sizeof(struct fadump_memory_range));
875	return 0;
876	}
877	static inline int fadump_add_mem_range(struct fadump_mrange_info *mrange_info,
878	u64 base, u64 end)
879	{
880	struct fadump_memory_range *mem_ranges = mrange_info->mem_ranges;
881	bool is_adjacent = false;
882	u64 start, size;
883
884	if (base == end)
885	return 0;
886
887	/*
888	* Fold adjacent memory ranges to bring down the memory ranges/
889	* PT_LOAD segments count.
890	*/
891	if (mrange_info->mem_range_cnt) {
892	start = mem_ranges[mrange_info->mem_range_cnt - 1].base;
893	size = mem_ranges[mrange_info->mem_range_cnt - 1].size;
894
895	/*
896	* Boot memory area needs separate PT_LOAD segment(s) as it
897	* is moved to a different location at the time of crash.
898	* So, fold only if the region is not boot memory area.
899	*/
900	if ((start + size) == base && start >= fw_dump.boot_mem_top)
901	is_adjacent = true;
902	}
903	if (!is_adjacent) {
904	/* resize the array on reaching the limit */
905	if (mrange_info->mem_range_cnt == mrange_info->max_mem_ranges) {
906	int ret;
907
908	if (mrange_info->is_static) {
909	pr_err("Reached array size limit for %s memory ranges\n",
910	mrange_info->name);
911	return -ENOSPC;
912	}
913
914	ret = fadump_alloc_mem_ranges(mrange_info);
915	if (ret)
916	return ret;
917
918	/* Update to the new resized array */
919	mem_ranges = mrange_info->mem_ranges;
920	}
921
922	start = base;
923	mem_ranges[mrange_info->mem_range_cnt].base = start;
924	mrange_info->mem_range_cnt++;
925	}
926
927	mem_ranges[mrange_info->mem_range_cnt - 1].size = (end - start);
928	pr_debug("%s_memory_range[%d] [%#016llx-%#016llx], %#llx bytes\n",
929	mrange_info->name, (mrange_info->mem_range_cnt - 1),
930	start, end - 1, (end - start));
931	return 0;
932	}
933
934	static int fadump_exclude_reserved_area(u64 start, u64 end)
935	{
936	u64 ra_start, ra_end;
937	int ret = 0;
938
939	ra_start = fw_dump.reserve_dump_area_start;
940	ra_end = ra_start + fw_dump.reserve_dump_area_size;
941
942	if ((ra_start < end) && (ra_end > start)) {
943	if ((start < ra_start) && (end > ra_end)) {
944	ret = fadump_add_mem_range(mrange_info: &crash_mrange_info,
945	base: start, end: ra_start);
946	if (ret)
947	return ret;
948
949	ret = fadump_add_mem_range(mrange_info: &crash_mrange_info,
950	base: ra_end, end);
951	} else if (start < ra_start) {
952	ret = fadump_add_mem_range(mrange_info: &crash_mrange_info,
953	base: start, end: ra_start);
954	} else if (ra_end < end) {
955	ret = fadump_add_mem_range(mrange_info: &crash_mrange_info,
956	base: ra_end, end);
957	}
958	} else
959	ret = fadump_add_mem_range(mrange_info: &crash_mrange_info, base: start, end);
960
961	return ret;
962	}
963
964	static int fadump_init_elfcore_header(char *bufp)
965	{
966	struct elfhdr *elf;
967
968	elf = (struct elfhdr *) bufp;
969	bufp += sizeof(struct elfhdr);
970	memcpy(elf->e_ident, ELFMAG, SELFMAG);
971	elf->e_ident[EI_CLASS] = ELF_CLASS;
972	elf->e_ident[EI_DATA] = ELF_DATA;
973	elf->e_ident[EI_VERSION] = EV_CURRENT;
974	elf->e_ident[EI_OSABI] = ELF_OSABI;
975	memset(elf->e_ident+EI_PAD, 0, EI_NIDENT-EI_PAD);
976	elf->e_type = ET_CORE;
977	elf->e_machine = ELF_ARCH;
978	elf->e_version = EV_CURRENT;
979	elf->e_entry = 0;
980	elf->e_phoff = sizeof(struct elfhdr);
981	elf->e_shoff = 0;
982
983	if (IS_ENABLED(CONFIG_PPC64_ELF_ABI_V2))
984	elf->e_flags = 2;
985	else if (IS_ENABLED(CONFIG_PPC64_ELF_ABI_V1))
986	elf->e_flags = 1;
987	else
988	elf->e_flags = 0;
989
990	elf->e_ehsize = sizeof(struct elfhdr);
991	elf->e_phentsize = sizeof(struct elf_phdr);
992	elf->e_phnum = 0;
993	elf->e_shentsize = 0;
994	elf->e_shnum = 0;
995	elf->e_shstrndx = 0;
996
997	return 0;
998	}
999
1000	/*
1001	* Traverse through memblock structure and setup crash memory ranges. These
1002	* ranges will be used create PT_LOAD program headers in elfcore header.
1003	*/
1004	static int fadump_setup_crash_memory_ranges(void)
1005	{
1006	u64 i, start, end;
1007	int ret;
1008
1009	pr_debug("Setup crash memory ranges.\n");
1010	crash_mrange_info.mem_range_cnt = 0;
1011
1012	/*
1013	* Boot memory region(s) registered with firmware are moved to
1014	* different location at the time of crash. Create separate program
1015	* header(s) for this memory chunk(s) with the correct offset.
1016	*/
1017	for (i = 0; i < fw_dump.boot_mem_regs_cnt; i++) {
1018	start = fw_dump.boot_mem_addr[i];
1019	end = start + fw_dump.boot_mem_sz[i];
1020	ret = fadump_add_mem_range(mrange_info: &crash_mrange_info, base: start, end);
1021	if (ret)
1022	return ret;
1023	}
1024
1025	for_each_mem_range(i, &start, &end) {
1026	/*
1027	* skip the memory chunk that is already added
1028	* (0 through boot_memory_top).
1029	*/
1030	if (start < fw_dump.boot_mem_top) {
1031	if (end > fw_dump.boot_mem_top)
1032	start = fw_dump.boot_mem_top;
1033	else
1034	continue;
1035	}
1036
1037	/* add this range excluding the reserved dump area. */
1038	ret = fadump_exclude_reserved_area(start, end);
1039	if (ret)
1040	return ret;
1041	}
1042
1043	return 0;
1044	}
1045
1046	/*
1047	* If the given physical address falls within the boot memory region then
1048	* return the relocated address that points to the dump region reserved
1049	* for saving initial boot memory contents.
1050	*/
1051	static inline unsigned long fadump_relocate(unsigned long paddr)
1052	{
1053	unsigned long raddr, rstart, rend, rlast, hole_size;
1054	int i;
1055
1056	hole_size = 0;
1057	rlast = 0;
1058	raddr = paddr;
1059	for (i = 0; i < fw_dump.boot_mem_regs_cnt; i++) {
1060	rstart = fw_dump.boot_mem_addr[i];
1061	rend = rstart + fw_dump.boot_mem_sz[i];
1062	hole_size += (rstart - rlast);
1063
1064	if (paddr >= rstart && paddr < rend) {
1065	raddr += fw_dump.boot_mem_dest_addr - hole_size;
1066	break;
1067	}
1068
1069	rlast = rend;
1070	}
1071
1072	pr_debug("vmcoreinfo: paddr = 0x%lx, raddr = 0x%lx\n", paddr, raddr);
1073	return raddr;
1074	}
1075
1076	static int fadump_create_elfcore_headers(char *bufp)
1077	{
1078	unsigned long long raddr, offset;
1079	struct elf_phdr *phdr;
1080	struct elfhdr *elf;
1081	int i, j;
1082
1083	fadump_init_elfcore_header(bufp);
1084	elf = (struct elfhdr *)bufp;
1085	bufp += sizeof(struct elfhdr);
1086
1087	/*
1088	* setup ELF PT_NOTE, place holder for cpu notes info. The notes info
1089	* will be populated during second kernel boot after crash. Hence
1090	* this PT_NOTE will always be the first elf note.
1091	*
1092	* NOTE: Any new ELF note addition should be placed after this note.
1093	*/
1094	phdr = (struct elf_phdr *)bufp;
1095	bufp += sizeof(struct elf_phdr);
1096	phdr->p_type = PT_NOTE;
1097	phdr->p_flags = 0;
1098	phdr->p_vaddr = 0;
1099	phdr->p_align = 0;
1100
1101	phdr->p_offset = 0;
1102	phdr->p_paddr = 0;
1103	phdr->p_filesz = 0;
1104	phdr->p_memsz = 0;
1105
1106	(elf->e_phnum)++;
1107
1108	/* setup ELF PT_NOTE for vmcoreinfo */
1109	phdr = (struct elf_phdr *)bufp;
1110	bufp += sizeof(struct elf_phdr);
1111	phdr->p_type = PT_NOTE;
1112	phdr->p_flags = 0;
1113	phdr->p_vaddr = 0;
1114	phdr->p_align = 0;
1115
1116	phdr->p_paddr = fadump_relocate(paddr: paddr_vmcoreinfo_note());
1117	phdr->p_offset = phdr->p_paddr;
1118	phdr->p_memsz = phdr->p_filesz = VMCOREINFO_NOTE_SIZE;
1119
1120	/* Increment number of program headers. */
1121	(elf->e_phnum)++;
1122
1123	/* setup PT_LOAD sections. */
1124	j = 0;
1125	offset = 0;
1126	raddr = fw_dump.boot_mem_addr[0];
1127	for (i = 0; i < crash_mrange_info.mem_range_cnt; i++) {
1128	u64 mbase, msize;
1129
1130	mbase = crash_mrange_info.mem_ranges[i].base;
1131	msize = crash_mrange_info.mem_ranges[i].size;
1132	if (!msize)
1133	continue;
1134
1135	phdr = (struct elf_phdr *)bufp;
1136	bufp += sizeof(struct elf_phdr);
1137	phdr->p_type = PT_LOAD;
1138	phdr->p_flags = PF_R|PF_W|PF_X;
1139	phdr->p_offset = mbase;
1140
1141	if (mbase == raddr) {
1142	/*
1143	* The entire real memory region will be moved by
1144	* firmware to the specified destination_address.
1145	* Hence set the correct offset.
1146	*/
1147	phdr->p_offset = fw_dump.boot_mem_dest_addr + offset;
1148	if (j < (fw_dump.boot_mem_regs_cnt - 1)) {
1149	offset += fw_dump.boot_mem_sz[j];
1150	raddr = fw_dump.boot_mem_addr[++j];
1151	}
1152	}
1153
1154	phdr->p_paddr = mbase;
1155	phdr->p_vaddr = (unsigned long)__va(mbase);
1156	phdr->p_filesz = msize;
1157	phdr->p_memsz = msize;
1158	phdr->p_align = 0;
1159
1160	/* Increment number of program headers. */
1161	(elf->e_phnum)++;
1162	}
1163	return 0;
1164	}
1165
1166	static unsigned long init_fadump_header(unsigned long addr)
1167	{
1168	struct fadump_crash_info_header *fdh;
1169
1170	if (!addr)
1171	return 0;
1172
1173	fdh = __va(addr);
1174	addr += sizeof(struct fadump_crash_info_header);
1175
1176	memset(fdh, 0, sizeof(struct fadump_crash_info_header));
1177	fdh->magic_number = FADUMP_CRASH_INFO_MAGIC;
1178	fdh->elfcorehdr_addr = addr;
1179	/* We will set the crashing cpu id in crash_fadump() during crash. */
1180	fdh->crashing_cpu = FADUMP_CPU_UNKNOWN;
1181	/*
1182	* When LPAR is terminated by PYHP, ensure all possible CPUs'
1183	* register data is processed while exporting the vmcore.
1184	*/
1185	fdh->cpu_mask = *cpu_possible_mask;
1186
1187	return addr;
1188	}
1189
1190	static int register_fadump(void)
1191	{
1192	unsigned long addr;
1193	void *vaddr;
1194	int ret;
1195
1196	/*
1197	* If no memory is reserved then we can not register for firmware-
1198	* assisted dump.
1199	*/
1200	if (!fw_dump.reserve_dump_area_size)
1201	return -ENODEV;
1202
1203	ret = fadump_setup_crash_memory_ranges();
1204	if (ret)
1205	return ret;
1206
1207	addr = fw_dump.fadumphdr_addr;
1208
1209	/* Initialize fadump crash info header. */
1210	addr = init_fadump_header(addr);
1211	vaddr = __va(addr);
1212
1213	pr_debug("Creating ELF core headers at %#016lx\n", addr);
1214	fadump_create_elfcore_headers(bufp: vaddr);
1215
1216	/* register the future kernel dump with firmware. */
1217	pr_debug("Registering for firmware-assisted kernel dump...\n");
1218	return fw_dump.ops->fadump_register(&fw_dump);
1219	}
1220
1221	void fadump_cleanup(void)
1222	{
1223	if (!fw_dump.fadump_supported)
1224	return;
1225
1226	/* Invalidate the registration only if dump is active. */
1227	if (fw_dump.dump_active) {
1228	pr_debug("Invalidating firmware-assisted dump registration\n");
1229	fw_dump.ops->fadump_invalidate(&fw_dump);
1230	} else if (fw_dump.dump_registered) {
1231	/* Un-register Firmware-assisted dump if it was registered. */
1232	fw_dump.ops->fadump_unregister(&fw_dump);
1233	fadump_free_mem_ranges(mrange_info: &crash_mrange_info);
1234	}
1235
1236	if (fw_dump.ops->fadump_cleanup)
1237	fw_dump.ops->fadump_cleanup(&fw_dump);
1238	}
1239
1240	static void fadump_free_reserved_memory(unsigned long start_pfn,
1241	unsigned long end_pfn)
1242	{
1243	unsigned long pfn;
1244	unsigned long time_limit = jiffies + HZ;
1245
1246	pr_info("freeing reserved memory (0x%llx - 0x%llx)\n",
1247	PFN_PHYS(start_pfn), PFN_PHYS(end_pfn));
1248
1249	for (pfn = start_pfn; pfn < end_pfn; pfn++) {
1250	free_reserved_page(pfn_to_page(pfn));
1251
1252	if (time_after(jiffies, time_limit)) {
1253	cond_resched();
1254	time_limit = jiffies + HZ;
1255	}
1256	}
1257	}
1258
1259	/*
1260	* Skip memory holes and free memory that was actually reserved.
1261	*/
1262	static void fadump_release_reserved_area(u64 start, u64 end)
1263	{
1264	unsigned long reg_spfn, reg_epfn;
1265	u64 tstart, tend, spfn, epfn;
1266	int i;
1267
1268	spfn = PHYS_PFN(start);
1269	epfn = PHYS_PFN(end);
1270
1271	for_each_mem_pfn_range(i, MAX_NUMNODES, &reg_spfn, &reg_epfn, NULL) {
1272	tstart = max_t(u64, spfn, reg_spfn);
1273	tend = min_t(u64, epfn, reg_epfn);
1274
1275	if (tstart < tend) {
1276	fadump_free_reserved_memory(start_pfn: tstart, end_pfn: tend);
1277
1278	if (tend == epfn)
1279	break;
1280
1281	spfn = tend;
1282	}
1283	}
1284	}
1285
1286	/*
1287	* Sort the mem ranges in-place and merge adjacent ranges
1288	* to minimize the memory ranges count.
1289	*/
1290	static void sort_and_merge_mem_ranges(struct fadump_mrange_info *mrange_info)
1291	{
1292	struct fadump_memory_range *mem_ranges;
1293	u64 base, size;
1294	int i, j, idx;
1295
1296	if (!reserved_mrange_info.mem_range_cnt)
1297	return;
1298
1299	/* Sort the memory ranges */
1300	mem_ranges = mrange_info->mem_ranges;
1301	for (i = 0; i < mrange_info->mem_range_cnt; i++) {
1302	idx = i;
1303	for (j = (i + 1); j < mrange_info->mem_range_cnt; j++) {
1304	if (mem_ranges[idx].base > mem_ranges[j].base)
1305	idx = j;
1306	}
1307	if (idx != i)
1308	swap(mem_ranges[idx], mem_ranges[i]);
1309	}
1310
1311	/* Merge adjacent reserved ranges */
1312	idx = 0;
1313	for (i = 1; i < mrange_info->mem_range_cnt; i++) {
1314	base = mem_ranges[i-1].base;
1315	size = mem_ranges[i-1].size;
1316	if (mem_ranges[i].base == (base + size))
1317	mem_ranges[idx].size += mem_ranges[i].size;
1318	else {
1319	idx++;
1320	if (i == idx)
1321	continue;
1322
1323	mem_ranges[idx] = mem_ranges[i];
1324	}
1325	}
1326	mrange_info->mem_range_cnt = idx + 1;
1327	}
1328
1329	/*
1330	* Scan reserved-ranges to consider them while reserving/releasing
1331	* memory for FADump.
1332	*/
1333	static void __init early_init_dt_scan_reserved_ranges(unsigned long node)
1334	{
1335	const __be32 *prop;
1336	int len, ret = -1;
1337	unsigned long i;
1338
1339	/* reserved-ranges already scanned */
1340	if (reserved_mrange_info.mem_range_cnt != 0)
1341	return;
1342
1343	prop = of_get_flat_dt_prop(node, name: "reserved-ranges", size: &len);
1344	if (!prop)
1345	return;
1346
1347	/*
1348	* Each reserved range is an (address,size) pair, 2 cells each,
1349	* totalling 4 cells per range.
1350	*/
1351	for (i = 0; i < len / (sizeof(*prop) * 4); i++) {
1352	u64 base, size;
1353
1354	base = of_read_number(cell: prop + (i * 4) + 0, size: 2);
1355	size = of_read_number(cell: prop + (i * 4) + 2, size: 2);
1356
1357	if (size) {
1358	ret = fadump_add_mem_range(mrange_info: &reserved_mrange_info,
1359	base, end: base + size);
1360	if (ret < 0) {
1361	pr_warn("some reserved ranges are ignored!\n");
1362	break;
1363	}
1364	}
1365	}
1366
1367	/* Compact reserved ranges */
1368	sort_and_merge_mem_ranges(mrange_info: &reserved_mrange_info);
1369	}
1370
1371	/*
1372	* Release the memory that was reserved during early boot to preserve the
1373	* crash'ed kernel's memory contents except reserved dump area (permanent
1374	* reservation) and reserved ranges used by F/W. The released memory will
1375	* be available for general use.
1376	*/
1377	static void fadump_release_memory(u64 begin, u64 end)
1378	{
1379	u64 ra_start, ra_end, tstart;
1380	int i, ret;
1381
1382	ra_start = fw_dump.reserve_dump_area_start;
1383	ra_end = ra_start + fw_dump.reserve_dump_area_size;
1384
1385	/*
1386	* If reserved ranges array limit is hit, overwrite the last reserved
1387	* memory range with reserved dump area to ensure it is excluded from
1388	* the memory being released (reused for next FADump registration).
1389	*/
1390	if (reserved_mrange_info.mem_range_cnt ==
1391	reserved_mrange_info.max_mem_ranges)
1392	reserved_mrange_info.mem_range_cnt--;
1393
1394	ret = fadump_add_mem_range(mrange_info: &reserved_mrange_info, base: ra_start, end: ra_end);
1395	if (ret != 0)
1396	return;
1397
1398	/* Get the reserved ranges list in order first. */
1399	sort_and_merge_mem_ranges(mrange_info: &reserved_mrange_info);
1400
1401	/* Exclude reserved ranges and release remaining memory */
1402	tstart = begin;
1403	for (i = 0; i < reserved_mrange_info.mem_range_cnt; i++) {
1404	ra_start = reserved_mrange_info.mem_ranges[i].base;
1405	ra_end = ra_start + reserved_mrange_info.mem_ranges[i].size;
1406
1407	if (tstart >= ra_end)
1408	continue;
1409
1410	if (tstart < ra_start)
1411	fadump_release_reserved_area(start: tstart, end: ra_start);
1412	tstart = ra_end;
1413	}
1414
1415	if (tstart < end)
1416	fadump_release_reserved_area(start: tstart, end);
1417	}
1418
1419	static void fadump_invalidate_release_mem(void)
1420	{
1421	mutex_lock(&fadump_mutex);
1422	if (!fw_dump.dump_active) {
1423	mutex_unlock(lock: &fadump_mutex);
1424	return;
1425	}
1426
1427	fadump_cleanup();
1428	mutex_unlock(lock: &fadump_mutex);
1429
1430	fadump_release_memory(begin: fw_dump.boot_mem_top, end: memblock_end_of_DRAM());
1431	fadump_free_cpu_notes_buf();
1432
1433	/*
1434	* Setup kernel metadata and initialize the kernel dump
1435	* memory structure for FADump re-registration.
1436	*/
1437	if (fw_dump.ops->fadump_setup_metadata &&
1438	(fw_dump.ops->fadump_setup_metadata(&fw_dump) < 0))
1439	pr_warn("Failed to setup kernel metadata!\n");
1440	fw_dump.ops->fadump_init_mem_struct(&fw_dump);
1441	}
1442
1443	static ssize_t release_mem_store(struct kobject *kobj,
1444	struct kobj_attribute *attr,
1445	const char *buf, size_t count)
1446	{
1447	int input = -1;
1448
1449	if (!fw_dump.dump_active)
1450	return -EPERM;
1451
1452	if (kstrtoint(s: buf, base: 0, res: &input))
1453	return -EINVAL;
1454
1455	if (input == 1) {
1456	/*
1457	* Take away the '/proc/vmcore'. We are releasing the dump
1458	* memory, hence it will not be valid anymore.
1459	*/
1460	#ifdef CONFIG_PROC_VMCORE
1461	vmcore_cleanup();
1462	#endif
1463	fadump_invalidate_release_mem();
1464
1465	} else
1466	return -EINVAL;
1467	return count;
1468	}
1469
1470	/* Release the reserved memory and disable the FADump */
1471	static void __init unregister_fadump(void)
1472	{
1473	fadump_cleanup();
1474	fadump_release_memory(begin: fw_dump.reserve_dump_area_start,
1475	end: fw_dump.reserve_dump_area_size);
1476	fw_dump.fadump_enabled = 0;
1477	kobject_put(kobj: fadump_kobj);
1478	}
1479
1480	static ssize_t enabled_show(struct kobject *kobj,
1481	struct kobj_attribute *attr,
1482	char *buf)
1483	{
1484	return sprintf(buf, fmt: "%d\n", fw_dump.fadump_enabled);
1485	}
1486
1487	static ssize_t mem_reserved_show(struct kobject *kobj,
1488	struct kobj_attribute *attr,
1489	char *buf)
1490	{
1491	return sprintf(buf, fmt: "%ld\n", fw_dump.reserve_dump_area_size);
1492	}
1493
1494	static ssize_t registered_show(struct kobject *kobj,
1495	struct kobj_attribute *attr,
1496	char *buf)
1497	{
1498	return sprintf(buf, fmt: "%d\n", fw_dump.dump_registered);
1499	}
1500
1501	static ssize_t registered_store(struct kobject *kobj,
1502	struct kobj_attribute *attr,
1503	const char *buf, size_t count)
1504	{
1505	int ret = 0;
1506	int input = -1;
1507
1508	if (!fw_dump.fadump_enabled || fw_dump.dump_active)
1509	return -EPERM;
1510
1511	if (kstrtoint(s: buf, base: 0, res: &input))
1512	return -EINVAL;
1513
1514	mutex_lock(&fadump_mutex);
1515
1516	switch (input) {
1517	case 0:
1518	if (fw_dump.dump_registered == 0) {
1519	goto unlock_out;
1520	}
1521
1522	/* Un-register Firmware-assisted dump */
1523	pr_debug("Un-register firmware-assisted dump\n");
1524	fw_dump.ops->fadump_unregister(&fw_dump);
1525	break;
1526	case 1:
1527	if (fw_dump.dump_registered == 1) {
1528	/* Un-register Firmware-assisted dump */
1529	fw_dump.ops->fadump_unregister(&fw_dump);
1530	}
1531	/* Register Firmware-assisted dump */
1532	ret = register_fadump();
1533	break;
1534	default:
1535	ret = -EINVAL;
1536	break;
1537	}
1538
1539	unlock_out:
1540	mutex_unlock(lock: &fadump_mutex);
1541	return ret < 0 ? ret : count;
1542	}
1543
1544	static int fadump_region_show(struct seq_file *m, void *private)
1545	{
1546	if (!fw_dump.fadump_enabled)
1547	return 0;
1548
1549	mutex_lock(&fadump_mutex);
1550	fw_dump.ops->fadump_region_show(&fw_dump, m);
1551	mutex_unlock(lock: &fadump_mutex);
1552	return 0;
1553	}
1554
1555	static struct kobj_attribute release_attr = __ATTR_WO(release_mem);
1556	static struct kobj_attribute enable_attr = __ATTR_RO(enabled);
1557	static struct kobj_attribute register_attr = __ATTR_RW(registered);
1558	static struct kobj_attribute mem_reserved_attr = __ATTR_RO(mem_reserved);
1559
1560	static struct attribute *fadump_attrs[] = {
1561	&enable_attr.attr,
1562	&register_attr.attr,
1563	&mem_reserved_attr.attr,
1564	NULL,
1565	};
1566
1567	ATTRIBUTE_GROUPS(fadump);
1568
1569	DEFINE_SHOW_ATTRIBUTE(fadump_region);
1570
1571	static void __init fadump_init_files(void)
1572	{
1573	int rc = 0;
1574
1575	fadump_kobj = kobject_create_and_add(name: "fadump", parent: kernel_kobj);
1576	if (!fadump_kobj) {
1577	pr_err("failed to create fadump kobject\n");
1578	return;
1579	}
1580
1581	debugfs_create_file(name: "fadump_region", mode: 0444, parent: arch_debugfs_dir, NULL,
1582	fops: &fadump_region_fops);
1583
1584	if (fw_dump.dump_active) {
1585	rc = sysfs_create_file(kobj: fadump_kobj, attr: &release_attr.attr);
1586	if (rc)
1587	pr_err("unable to create release_mem sysfs file (%d)\n",
1588	rc);
1589	}
1590
1591	rc = sysfs_create_groups(kobj: fadump_kobj, groups: fadump_groups);
1592	if (rc) {
1593	pr_err("sysfs group creation failed (%d), unregistering FADump",
1594	rc);
1595	unregister_fadump();
1596	return;
1597	}
1598
1599	/*
1600	* The FADump sysfs are moved from kernel_kobj to fadump_kobj need to
1601	* create symlink at old location to maintain backward compatibility.
1602	*
1603	* - fadump_enabled -> fadump/enabled
1604	* - fadump_registered -> fadump/registered
1605	* - fadump_release_mem -> fadump/release_mem
1606	*/
1607	rc = compat_only_sysfs_link_entry_to_kobj(kobj: kernel_kobj, target_kobj: fadump_kobj,
1608	target_name: "enabled", symlink_name: "fadump_enabled");
1609	if (rc) {
1610	pr_err("unable to create fadump_enabled symlink (%d)", rc);
1611	return;
1612	}
1613
1614	rc = compat_only_sysfs_link_entry_to_kobj(kobj: kernel_kobj, target_kobj: fadump_kobj,
1615	target_name: "registered",
1616	symlink_name: "fadump_registered");
1617	if (rc) {
1618	pr_err("unable to create fadump_registered symlink (%d)", rc);
1619	sysfs_remove_link(kobj: kernel_kobj, name: "fadump_enabled");
1620	return;
1621	}
1622
1623	if (fw_dump.dump_active) {
1624	rc = compat_only_sysfs_link_entry_to_kobj(kobj: kernel_kobj,
1625	target_kobj: fadump_kobj,
1626	target_name: "release_mem",
1627	symlink_name: "fadump_release_mem");
1628	if (rc)
1629	pr_err("unable to create fadump_release_mem symlink (%d)",
1630	rc);
1631	}
1632	return;
1633	}
1634
1635	/*
1636	* Prepare for firmware-assisted dump.
1637	*/
1638	int __init setup_fadump(void)
1639	{
1640	if (!fw_dump.fadump_supported)
1641	return 0;
1642
1643	fadump_init_files();
1644	fadump_show_config();
1645
1646	if (!fw_dump.fadump_enabled)
1647	return 1;
1648
1649	/*
1650	* If dump data is available then see if it is valid and prepare for
1651	* saving it to the disk.
1652	*/
1653	if (fw_dump.dump_active) {
1654	/*
1655	* if dump process fails then invalidate the registration
1656	* and release memory before proceeding for re-registration.
1657	*/
1658	if (fw_dump.ops->fadump_process(&fw_dump) < 0)
1659	fadump_invalidate_release_mem();
1660	}
1661	/* Initialize the kernel dump memory structure and register with f/w */
1662	else if (fw_dump.reserve_dump_area_size) {
1663	fw_dump.ops->fadump_init_mem_struct(&fw_dump);
1664	register_fadump();
1665	}
1666
1667	/*
1668	* In case of panic, fadump is triggered via ppc_panic_event()
1669	* panic notifier. Setting crash_kexec_post_notifiers to 'true'
1670	* lets panic() function take crash friendly path before panic
1671	* notifiers are invoked.
1672	*/
1673	crash_kexec_post_notifiers = true;
1674
1675	return 1;
1676	}
1677	/*
1678	* Use subsys_initcall_sync() here because there is dependency with
1679	* crash_save_vmcoreinfo_init(), which must run first to ensure vmcoreinfo initialization
1680	* is done before registering with f/w.
1681	*/
1682	subsys_initcall_sync(setup_fadump);
1683	#else /* !CONFIG_PRESERVE_FA_DUMP */
1684
1685	/* Scan the Firmware Assisted dump configuration details. */
1686	int __init early_init_dt_scan_fw_dump(unsigned long node, const char *uname,
1687	int depth, void *data)
1688	{
1689	if ((depth != 1) || (strcmp(uname, "ibm,opal") != 0))
1690	return 0;
1691
1692	opal_fadump_dt_scan(&fw_dump, node);
1693	return 1;
1694	}
1695
1696	/*
1697	* When dump is active but PRESERVE_FA_DUMP is enabled on the kernel,
1698	* preserve crash data. The subsequent memory preserving kernel boot
1699	* is likely to process this crash data.
1700	*/
1701	int __init fadump_reserve_mem(void)
1702	{
1703	if (fw_dump.dump_active) {
1704	/*
1705	* If last boot has crashed then reserve all the memory
1706	* above boot memory to preserve crash data.
1707	*/
1708	pr_info("Preserving crash data for processing in next boot.\n");
1709	fadump_reserve_crash_area(fw_dump.boot_mem_top);
1710	} else
1711	pr_debug("FADump-aware kernel..\n");
1712
1713	return 1;
1714	}
1715	#endif /* CONFIG_PRESERVE_FA_DUMP */
1716
1717	/* Preserve everything above the base address */
1718	static void __init fadump_reserve_crash_area(u64 base)
1719	{
1720	u64 i, mstart, mend, msize;
1721
1722	for_each_mem_range(i, &mstart, &mend) {
1723	msize = mend - mstart;
1724
1725	if ((mstart + msize) < base)
1726	continue;
1727
1728	if (mstart < base) {
1729	msize -= (base - mstart);
1730	mstart = base;
1731	}
1732
1733	pr_info("Reserving %lluMB of memory at %#016llx for preserving crash data",
1734	(msize >> 20), mstart);
1735	memblock_reserve(base: mstart, size: msize);
1736	}
1737	}
1738
1739	unsigned long __init arch_reserved_kernel_pages(void)
1740	{
1741	return memblock_reserved_size() / PAGE_SIZE;
1742	}
1743