xref: /openbmc/linux/arch/powerpc/kernel/fadump.c (revision d1eb75e0)
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  */
fadump_cma_init(void)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, 0, "fadump_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(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
fadump_cma_init(void)133 static int __init fadump_cma_init(void) { return 1; }
134 #endif /* CONFIG_CMA */
135 
136 /* Scan the Firmware Assisted dump configuration details. */
early_init_dt_scan_fw_dump(unsigned long node,const char * uname,int depth,void * data)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  */
is_fadump_memory_area(u64 addr,unsigned long size)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 
should_fadump_crash(void)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 
is_fadump_active(void)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  */
is_fadump_mem_area_contiguous(u64 d_start,u64 d_end)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  */
is_fadump_boot_mem_contiguous(void)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  */
is_fadump_reserved_mem_contiguous(void)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. */
fadump_show_config(void)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  */
fadump_calculate_reserve_size(void)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(boot_command_line, memblock_phys_mem_size(),
316 				&size, &base);
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  */
get_fadump_area_size(void)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 
add_boot_mem_region(unsigned long rstart,unsigned long rsize)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  */
add_boot_mem_regions(unsigned long mstart,unsigned long msize)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 
fadump_get_boot_mem_regions(void)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(reg_start, size);
455 			break;
456 		}
457 
458 		mem_size -= size;
459 		cur_size += size;
460 		ret = add_boot_mem_regions(reg_start, 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  */
overlaps_reserved_ranges(u64 base,u64 end,int * idx)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  */
fadump_locate_reserve_mem(u64 base,u64 size)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, base+size, &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 
fadump_reserve_mem(void)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. */
early_fadump_param(char * p)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  */
early_fadump_reserve_mem(char * p)685 static int __init early_fadump_reserve_mem(char *p)
686 {
687 	if (p)
688 		fw_dump.reserve_bootvar = memparse(p, &p);
689 	return 0;
690 }
691 early_param("fadump_reserve_mem", early_fadump_reserve_mem);
692 
crash_fadump(struct pt_regs * regs,const char * str)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(&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(&cpus_in_fadump) < ncpus) && (--msecs > 0))
747 			mdelay(1);
748 	}
749 
750 	fw_dump.ops->fadump_trigger(fdh, str);
751 }
752 
fadump_regs_to_elf_notes(u32 * buf,struct pt_regs * regs)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(&prstatus.pr_reg, regs);
763 	buf = append_elf_note(buf, CRASH_CORE_NOTE_NAME, NT_PRSTATUS,
764 			      &prstatus, sizeof(prstatus));
765 	return buf;
766 }
767 
fadump_update_elfcore_header(char * bufp)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 
fadump_alloc_buffer(unsigned long size)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 + i);
800 	return vaddr;
801 }
802 
fadump_free_buffer(unsigned long vaddr,unsigned long size)803 static void fadump_free_buffer(unsigned long vaddr, unsigned long size)
804 {
805 	free_reserved_area((void *)vaddr, (void *)(vaddr + size), -1, NULL);
806 }
807 
fadump_setup_cpu_notes_buf(u32 num_cpus)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(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 
fadump_free_cpu_notes_buf(void)827 void fadump_free_cpu_notes_buf(void)
828 {
829 	if (!fw_dump.cpu_notes_buf_vaddr)
830 		return;
831 
832 	fadump_free_buffer(fw_dump.cpu_notes_buf_vaddr,
833 			   fw_dump.cpu_notes_buf_size);
834 	fw_dump.cpu_notes_buf_vaddr = 0;
835 	fw_dump.cpu_notes_buf_size = 0;
836 }
837 
fadump_free_mem_ranges(struct fadump_mrange_info * mrange_info)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(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  */
fadump_alloc_mem_ranges(struct fadump_mrange_info * mrange_info)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(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 }
fadump_add_mem_range(struct fadump_mrange_info * mrange_info,u64 base,u64 end)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 
fadump_exclude_reserved_area(u64 start,u64 end)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(&crash_mrange_info,
945 						   start, ra_start);
946 			if (ret)
947 				return ret;
948 
949 			ret = fadump_add_mem_range(&crash_mrange_info,
950 						   ra_end, end);
951 		} else if (start < ra_start) {
952 			ret = fadump_add_mem_range(&crash_mrange_info,
953 						   start, ra_start);
954 		} else if (ra_end < end) {
955 			ret = fadump_add_mem_range(&crash_mrange_info,
956 						   ra_end, end);
957 		}
958 	} else
959 		ret = fadump_add_mem_range(&crash_mrange_info, start, end);
960 
961 	return ret;
962 }
963 
fadump_init_elfcore_header(char * bufp)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  */
fadump_setup_crash_memory_ranges(void)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(&crash_mrange_info, 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  */
fadump_relocate(unsigned long paddr)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 
fadump_create_elfcore_headers(char * bufp)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_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 
init_fadump_header(unsigned long addr)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 
register_fadump(void)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(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 
fadump_cleanup(void)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(&crash_mrange_info);
1234 	}
1235 
1236 	if (fw_dump.ops->fadump_cleanup)
1237 		fw_dump.ops->fadump_cleanup(&fw_dump);
1238 }
1239 
fadump_free_reserved_memory(unsigned long start_pfn,unsigned long end_pfn)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  */
fadump_release_reserved_area(u64 start,u64 end)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(tstart, 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  */
sort_and_merge_mem_ranges(struct fadump_mrange_info * mrange_info)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  */
early_init_dt_scan_reserved_ranges(unsigned long node)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, "reserved-ranges", &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(prop + (i * 4) + 0, 2);
1355 		size = of_read_number(prop + (i * 4) + 2, 2);
1356 
1357 		if (size) {
1358 			ret = fadump_add_mem_range(&reserved_mrange_info,
1359 						   base, 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(&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  */
fadump_release_memory(u64 begin,u64 end)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(&reserved_mrange_info, ra_start, ra_end);
1395 	if (ret != 0)
1396 		return;
1397 
1398 	/* Get the reserved ranges list in order first. */
1399 	sort_and_merge_mem_ranges(&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(tstart, ra_start);
1412 		tstart = ra_end;
1413 	}
1414 
1415 	if (tstart < end)
1416 		fadump_release_reserved_area(tstart, end);
1417 }
1418 
fadump_invalidate_release_mem(void)1419 static void fadump_invalidate_release_mem(void)
1420 {
1421 	mutex_lock(&fadump_mutex);
1422 	if (!fw_dump.dump_active) {
1423 		mutex_unlock(&fadump_mutex);
1424 		return;
1425 	}
1426 
1427 	fadump_cleanup();
1428 	mutex_unlock(&fadump_mutex);
1429 
1430 	fadump_release_memory(fw_dump.boot_mem_top, 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 
release_mem_store(struct kobject * kobj,struct kobj_attribute * attr,const char * buf,size_t count)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(buf, 0, &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 */
unregister_fadump(void)1471 static void __init unregister_fadump(void)
1472 {
1473 	fadump_cleanup();
1474 	fadump_release_memory(fw_dump.reserve_dump_area_start,
1475 			      fw_dump.reserve_dump_area_size);
1476 	fw_dump.fadump_enabled = 0;
1477 	kobject_put(fadump_kobj);
1478 }
1479 
enabled_show(struct kobject * kobj,struct kobj_attribute * attr,char * buf)1480 static ssize_t enabled_show(struct kobject *kobj,
1481 			    struct kobj_attribute *attr,
1482 			    char *buf)
1483 {
1484 	return sprintf(buf, "%d\n", fw_dump.fadump_enabled);
1485 }
1486 
mem_reserved_show(struct kobject * kobj,struct kobj_attribute * attr,char * buf)1487 static ssize_t mem_reserved_show(struct kobject *kobj,
1488 				 struct kobj_attribute *attr,
1489 				 char *buf)
1490 {
1491 	return sprintf(buf, "%ld\n", fw_dump.reserve_dump_area_size);
1492 }
1493 
registered_show(struct kobject * kobj,struct kobj_attribute * attr,char * buf)1494 static ssize_t registered_show(struct kobject *kobj,
1495 			       struct kobj_attribute *attr,
1496 			       char *buf)
1497 {
1498 	return sprintf(buf, "%d\n", fw_dump.dump_registered);
1499 }
1500 
registered_store(struct kobject * kobj,struct kobj_attribute * attr,const char * buf,size_t count)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(buf, 0, &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(&fadump_mutex);
1541 	return ret < 0 ? ret : count;
1542 }
1543 
fadump_region_show(struct seq_file * m,void * private)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(&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 
fadump_init_files(void)1571 static void __init fadump_init_files(void)
1572 {
1573 	int rc = 0;
1574 
1575 	fadump_kobj = kobject_create_and_add("fadump", kernel_kobj);
1576 	if (!fadump_kobj) {
1577 		pr_err("failed to create fadump kobject\n");
1578 		return;
1579 	}
1580 
1581 	debugfs_create_file("fadump_region", 0444, arch_debugfs_dir, NULL,
1582 			    &fadump_region_fops);
1583 
1584 	if (fw_dump.dump_active) {
1585 		rc = sysfs_create_file(fadump_kobj, &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(fadump_kobj, 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(kernel_kobj, fadump_kobj,
1608 						  "enabled", "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(kernel_kobj, fadump_kobj,
1615 						  "registered",
1616 						  "fadump_registered");
1617 	if (rc) {
1618 		pr_err("unable to create fadump_registered symlink (%d)", rc);
1619 		sysfs_remove_link(kernel_kobj, "fadump_enabled");
1620 		return;
1621 	}
1622 
1623 	if (fw_dump.dump_active) {
1624 		rc = compat_only_sysfs_link_entry_to_kobj(kernel_kobj,
1625 							  fadump_kobj,
1626 							  "release_mem",
1627 							  "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  */
setup_fadump(void)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. */
early_init_dt_scan_fw_dump(unsigned long node,const char * uname,int depth,void * data)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  */
fadump_reserve_mem(void)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 */
fadump_reserve_crash_area(u64 base)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(mstart, msize);
1736 	}
1737 }
1738 
arch_reserved_kernel_pages(void)1739 unsigned long __init arch_reserved_kernel_pages(void)
1740 {
1741 	return memblock_reserved_size() / PAGE_SIZE;
1742 }
1743