1 // SPDX-License-Identifier: GPL-2.0-or-later
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
10 * Copyright 2011 IBM Corporation
11 * Author: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
15 #define pr_fmt(fmt) "fadump: " fmt
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>
31 #include <asm/fadump.h>
32 #include <asm/fadump-internal.h>
33 #include <asm/setup.h>
34 #include <asm/interrupt.h>
37 * The CPU who acquired the lock to trigger the fadump crash should
38 * wait for other CPUs to enter.
40 * The timeout is in milliseconds.
42 #define CRASH_TIMEOUT 500
44 static struct fw_dump fw_dump;
46 static void __init fadump_reserve_crash_area(u64 base);
48 #ifndef CONFIG_PRESERVE_FA_DUMP
50 static struct kobject *fadump_kobj;
52 static atomic_t cpus_in_fadump;
53 static DEFINE_MUTEX(fadump_mutex);
55 static struct fadump_mrange_info crash_mrange_info = { "crash", NULL, 0, 0, 0, false };
57 #define RESERVED_RNGS_SZ 16384 /* 16K - 128 entries */
58 #define RESERVED_RNGS_CNT (RESERVED_RNGS_SZ / \
59 sizeof(struct fadump_memory_range))
60 static struct fadump_memory_range rngs[RESERVED_RNGS_CNT];
61 static struct fadump_mrange_info
62 reserved_mrange_info = { "reserved", rngs, RESERVED_RNGS_SZ, 0, RESERVED_RNGS_CNT, true };
64 static void __init early_init_dt_scan_reserved_ranges(unsigned long node);
67 static struct cma *fadump_cma;
70 * fadump_cma_init() - Initialize CMA area from a fadump reserved memory
72 * This function initializes CMA area from fadump reserved memory.
73 * The total size of fadump reserved memory covers for boot memory size
74 * + cpu data size + hpte size and metadata.
75 * Initialize only the area equivalent to boot memory size for CMA use.
76 * The reamining portion of fadump reserved memory will be not given
77 * to CMA and pages for thoes will stay reserved. boot memory size is
78 * aligned per CMA requirement to satisy cma_init_reserved_mem() call.
79 * But for some reason even if it fails we still have the memory reservation
80 * with us and we can still continue doing fadump.
82 static int __init fadump_cma_init(void)
84 unsigned long long base, size;
87 if (!fw_dump.fadump_enabled)
91 * Do not use CMA if user has provided fadump=nocma kernel parameter.
92 * Return 1 to continue with fadump old behaviour.
97 base = fw_dump.reserve_dump_area_start;
98 size = fw_dump.boot_memory_size;
103 rc = cma_init_reserved_mem(base, size, 0, "fadump_cma", &fadump_cma);
105 pr_err("Failed to init cma area for firmware-assisted dump,%d\n", rc);
107 * Though the CMA init has failed we still have memory
108 * reservation with us. The reserved memory will be
109 * blocked from production system usage. Hence return 1,
110 * so that we can continue with fadump.
116 * So we now have successfully initialized cma area for fadump.
118 pr_info("Initialized 0x%lx bytes cma area at %ldMB from 0x%lx "
119 "bytes of memory reserved for firmware-assisted dump\n",
120 cma_get_size(fadump_cma),
121 (unsigned long)cma_get_base(fadump_cma) >> 20,
122 fw_dump.reserve_dump_area_size);
126 static int __init fadump_cma_init(void) { return 1; }
127 #endif /* CONFIG_CMA */
129 /* Scan the Firmware Assisted dump configuration details. */
130 int __init early_init_dt_scan_fw_dump(unsigned long node, const char *uname,
131 int depth, void *data)
134 early_init_dt_scan_reserved_ranges(node);
141 if (strcmp(uname, "rtas") == 0) {
142 rtas_fadump_dt_scan(&fw_dump, node);
146 if (strcmp(uname, "ibm,opal") == 0) {
147 opal_fadump_dt_scan(&fw_dump, node);
155 * If fadump is registered, check if the memory provided
156 * falls within boot memory area and reserved memory area.
158 int is_fadump_memory_area(u64 addr, unsigned long size)
162 if (!fw_dump.dump_registered)
168 d_start = fw_dump.reserve_dump_area_start;
169 d_end = d_start + fw_dump.reserve_dump_area_size;
170 if (((addr + size) > d_start) && (addr <= d_end))
173 return (addr <= fw_dump.boot_mem_top);
176 int should_fadump_crash(void)
178 if (!fw_dump.dump_registered || !fw_dump.fadumphdr_addr)
183 int is_fadump_active(void)
185 return fw_dump.dump_active;
189 * Returns true, if there are no holes in memory area between d_start to d_end,
192 static bool is_fadump_mem_area_contiguous(u64 d_start, u64 d_end)
194 phys_addr_t reg_start, reg_end;
198 for_each_mem_range(i, ®_start, ®_end) {
199 start = max_t(u64, d_start, reg_start);
200 end = min_t(u64, d_end, reg_end);
202 /* Memory hole from d_start to start */
219 * Returns true, if there are no holes in boot memory area,
222 bool is_fadump_boot_mem_contiguous(void)
224 unsigned long d_start, d_end;
228 for (i = 0; i < fw_dump.boot_mem_regs_cnt; i++) {
229 d_start = fw_dump.boot_mem_addr[i];
230 d_end = d_start + fw_dump.boot_mem_sz[i];
232 ret = is_fadump_mem_area_contiguous(d_start, d_end);
241 * Returns true, if there are no holes in reserved memory area,
244 bool is_fadump_reserved_mem_contiguous(void)
248 d_start = fw_dump.reserve_dump_area_start;
249 d_end = d_start + fw_dump.reserve_dump_area_size;
250 return is_fadump_mem_area_contiguous(d_start, d_end);
253 /* Print firmware assisted dump configurations for debugging purpose. */
254 static void fadump_show_config(void)
258 pr_debug("Support for firmware-assisted dump (fadump): %s\n",
259 (fw_dump.fadump_supported ? "present" : "no support"));
261 if (!fw_dump.fadump_supported)
264 pr_debug("Fadump enabled : %s\n",
265 (fw_dump.fadump_enabled ? "yes" : "no"));
266 pr_debug("Dump Active : %s\n",
267 (fw_dump.dump_active ? "yes" : "no"));
268 pr_debug("Dump section sizes:\n");
269 pr_debug(" CPU state data size: %lx\n", fw_dump.cpu_state_data_size);
270 pr_debug(" HPTE region size : %lx\n", fw_dump.hpte_region_size);
271 pr_debug(" Boot memory size : %lx\n", fw_dump.boot_memory_size);
272 pr_debug(" Boot memory top : %llx\n", fw_dump.boot_mem_top);
273 pr_debug("Boot memory regions cnt: %llx\n", fw_dump.boot_mem_regs_cnt);
274 for (i = 0; i < fw_dump.boot_mem_regs_cnt; i++) {
275 pr_debug("[%03d] base = %llx, size = %llx\n", i,
276 fw_dump.boot_mem_addr[i], fw_dump.boot_mem_sz[i]);
281 * fadump_calculate_reserve_size(): reserve variable boot area 5% of System RAM
283 * Function to find the largest memory size we need to reserve during early
284 * boot process. This will be the size of the memory that is required for a
285 * kernel to boot successfully.
287 * This function has been taken from phyp-assisted dump feature implementation.
289 * returns larger of 256MB or 5% rounded down to multiples of 256MB.
291 * TODO: Come up with better approach to find out more accurate memory size
292 * that is required for a kernel to boot successfully.
295 static __init u64 fadump_calculate_reserve_size(void)
297 u64 base, size, bootmem_min;
300 if (fw_dump.reserve_bootvar)
301 pr_warn("'fadump_reserve_mem=' parameter is deprecated in favor of 'crashkernel=' parameter.\n");
304 * Check if the size is specified through crashkernel= cmdline
305 * option. If yes, then use that but ignore base as fadump reserves
306 * memory at a predefined offset.
308 ret = parse_crashkernel(boot_command_line, memblock_phys_mem_size(),
310 if (ret == 0 && size > 0) {
311 unsigned long max_size;
313 if (fw_dump.reserve_bootvar)
314 pr_info("Using 'crashkernel=' parameter for memory reservation.\n");
316 fw_dump.reserve_bootvar = (unsigned long)size;
319 * Adjust if the boot memory size specified is above
322 max_size = memblock_phys_mem_size() / MAX_BOOT_MEM_RATIO;
323 if (fw_dump.reserve_bootvar > max_size) {
324 fw_dump.reserve_bootvar = max_size;
325 pr_info("Adjusted boot memory size to %luMB\n",
326 (fw_dump.reserve_bootvar >> 20));
329 return fw_dump.reserve_bootvar;
330 } else if (fw_dump.reserve_bootvar) {
332 * 'fadump_reserve_mem=' is being used to reserve memory
333 * for firmware-assisted dump.
335 return fw_dump.reserve_bootvar;
338 /* divide by 20 to get 5% of value */
339 size = memblock_phys_mem_size() / 20;
341 /* round it down in multiples of 256 */
342 size = size & ~0x0FFFFFFFUL;
344 /* Truncate to memory_limit. We don't want to over reserve the memory.*/
345 if (memory_limit && size > memory_limit)
348 bootmem_min = fw_dump.ops->fadump_get_bootmem_min();
349 return (size > bootmem_min ? size : bootmem_min);
353 * Calculate the total memory size required to be reserved for
354 * firmware-assisted dump registration.
356 static unsigned long get_fadump_area_size(void)
358 unsigned long size = 0;
360 size += fw_dump.cpu_state_data_size;
361 size += fw_dump.hpte_region_size;
362 size += fw_dump.boot_memory_size;
363 size += sizeof(struct fadump_crash_info_header);
364 size += sizeof(struct elfhdr); /* ELF core header.*/
365 size += sizeof(struct elf_phdr); /* place holder for cpu notes */
366 /* Program headers for crash memory regions. */
367 size += sizeof(struct elf_phdr) * (memblock_num_regions(memory) + 2);
369 size = PAGE_ALIGN(size);
371 /* This is to hold kernel metadata on platforms that support it */
372 size += (fw_dump.ops->fadump_get_metadata_size ?
373 fw_dump.ops->fadump_get_metadata_size() : 0);
377 static int __init add_boot_mem_region(unsigned long rstart,
380 int i = fw_dump.boot_mem_regs_cnt++;
382 if (fw_dump.boot_mem_regs_cnt > FADUMP_MAX_MEM_REGS) {
383 fw_dump.boot_mem_regs_cnt = FADUMP_MAX_MEM_REGS;
387 pr_debug("Added boot memory range[%d] [%#016lx-%#016lx)\n",
388 i, rstart, (rstart + rsize));
389 fw_dump.boot_mem_addr[i] = rstart;
390 fw_dump.boot_mem_sz[i] = rsize;
395 * Firmware usually has a hard limit on the data it can copy per region.
396 * Honour that by splitting a memory range into multiple regions.
398 static int __init add_boot_mem_regions(unsigned long mstart,
401 unsigned long rstart, rsize, max_size;
405 max_size = fw_dump.max_copy_size ? fw_dump.max_copy_size : msize;
407 if (msize > max_size)
412 ret = add_boot_mem_region(rstart, rsize);
423 static int __init fadump_get_boot_mem_regions(void)
425 unsigned long size, cur_size, hole_size, last_end;
426 unsigned long mem_size = fw_dump.boot_memory_size;
427 phys_addr_t reg_start, reg_end;
431 fw_dump.boot_mem_regs_cnt = 0;
436 for_each_mem_range(i, ®_start, ®_end) {
437 size = reg_end - reg_start;
438 hole_size += (reg_start - last_end);
440 if ((cur_size + size) >= mem_size) {
441 size = (mem_size - cur_size);
442 ret = add_boot_mem_regions(reg_start, size);
448 ret = add_boot_mem_regions(reg_start, size);
454 fw_dump.boot_mem_top = PAGE_ALIGN(fw_dump.boot_memory_size + hole_size);
460 * Returns true, if the given range overlaps with reserved memory ranges
461 * starting at idx. Also, updates idx to index of overlapping memory range
462 * with the given memory range.
465 static bool overlaps_reserved_ranges(u64 base, u64 end, int *idx)
470 for (i = *idx; i < reserved_mrange_info.mem_range_cnt; i++) {
471 u64 rbase = reserved_mrange_info.mem_ranges[i].base;
472 u64 rend = rbase + reserved_mrange_info.mem_ranges[i].size;
477 if ((end > rbase) && (base < rend)) {
488 * Locate a suitable memory area to reserve memory for FADump. While at it,
489 * lookup reserved-ranges & avoid overlap with them, as they are used by F/W.
491 static u64 __init fadump_locate_reserve_mem(u64 base, u64 size)
493 struct fadump_memory_range *mrngs;
494 phys_addr_t mstart, mend;
498 mrngs = reserved_mrange_info.mem_ranges;
499 for_each_free_mem_range(i, NUMA_NO_NODE, MEMBLOCK_NONE,
500 &mstart, &mend, NULL) {
501 pr_debug("%llu) mstart: %llx, mend: %llx, base: %llx\n",
502 i, mstart, mend, base);
505 base = PAGE_ALIGN(mstart);
507 while ((mend > base) && ((mend - base) >= size)) {
508 if (!overlaps_reserved_ranges(base, base+size, &idx)) {
513 base = mrngs[idx].base + mrngs[idx].size;
514 base = PAGE_ALIGN(base);
522 int __init fadump_reserve_mem(void)
524 u64 base, size, mem_boundary, bootmem_min;
527 if (!fw_dump.fadump_enabled)
530 if (!fw_dump.fadump_supported) {
531 pr_info("Firmware-Assisted Dump is not supported on this hardware\n");
536 * Initialize boot memory size
537 * If dump is active then we have already calculated the size during
540 if (!fw_dump.dump_active) {
541 fw_dump.boot_memory_size =
542 PAGE_ALIGN(fadump_calculate_reserve_size());
544 if (!fw_dump.nocma) {
545 fw_dump.boot_memory_size =
546 ALIGN(fw_dump.boot_memory_size,
547 FADUMP_CMA_ALIGNMENT);
551 bootmem_min = fw_dump.ops->fadump_get_bootmem_min();
552 if (fw_dump.boot_memory_size < bootmem_min) {
553 pr_err("Can't enable fadump with boot memory size (0x%lx) less than 0x%llx\n",
554 fw_dump.boot_memory_size, bootmem_min);
558 if (!fadump_get_boot_mem_regions()) {
559 pr_err("Too many holes in boot memory area to enable fadump\n");
565 * Calculate the memory boundary.
566 * If memory_limit is less than actual memory boundary then reserve
567 * the memory for fadump beyond the memory_limit and adjust the
568 * memory_limit accordingly, so that the running kernel can run with
569 * specified memory_limit.
571 if (memory_limit && memory_limit < memblock_end_of_DRAM()) {
572 size = get_fadump_area_size();
573 if ((memory_limit + size) < memblock_end_of_DRAM())
574 memory_limit += size;
576 memory_limit = memblock_end_of_DRAM();
577 printk(KERN_INFO "Adjusted memory_limit for firmware-assisted"
578 " dump, now %#016llx\n", memory_limit);
581 mem_boundary = memory_limit;
583 mem_boundary = memblock_end_of_DRAM();
585 base = fw_dump.boot_mem_top;
586 size = get_fadump_area_size();
587 fw_dump.reserve_dump_area_size = size;
588 if (fw_dump.dump_active) {
589 pr_info("Firmware-assisted dump is active.\n");
591 #ifdef CONFIG_HUGETLB_PAGE
593 * FADump capture kernel doesn't care much about hugepages.
594 * In fact, handling hugepages in capture kernel is asking for
595 * trouble. So, disable HugeTLB support when fadump is active.
597 hugetlb_disabled = true;
600 * If last boot has crashed then reserve all the memory
601 * above boot memory size so that we don't touch it until
602 * dump is written to disk by userspace tool. This memory
603 * can be released for general use by invalidating fadump.
605 fadump_reserve_crash_area(base);
607 pr_debug("fadumphdr_addr = %#016lx\n", fw_dump.fadumphdr_addr);
608 pr_debug("Reserve dump area start address: 0x%lx\n",
609 fw_dump.reserve_dump_area_start);
612 * Reserve memory at an offset closer to bottom of the RAM to
613 * minimize the impact of memory hot-remove operation.
615 base = fadump_locate_reserve_mem(base, size);
617 if (!base || (base + size > mem_boundary)) {
618 pr_err("Failed to find memory chunk for reservation!\n");
621 fw_dump.reserve_dump_area_start = base;
624 * Calculate the kernel metadata address and register it with
625 * f/w if the platform supports.
627 if (fw_dump.ops->fadump_setup_metadata &&
628 (fw_dump.ops->fadump_setup_metadata(&fw_dump) < 0))
631 if (memblock_reserve(base, size)) {
632 pr_err("Failed to reserve memory!\n");
636 pr_info("Reserved %lldMB of memory at %#016llx (System RAM: %lldMB)\n",
637 (size >> 20), base, (memblock_phys_mem_size() >> 20));
639 ret = fadump_cma_init();
644 fw_dump.fadump_enabled = 0;
648 /* Look for fadump= cmdline option. */
649 static int __init early_fadump_param(char *p)
654 if (strncmp(p, "on", 2) == 0)
655 fw_dump.fadump_enabled = 1;
656 else if (strncmp(p, "off", 3) == 0)
657 fw_dump.fadump_enabled = 0;
658 else if (strncmp(p, "nocma", 5) == 0) {
659 fw_dump.fadump_enabled = 1;
665 early_param("fadump", early_fadump_param);
668 * Look for fadump_reserve_mem= cmdline option
669 * TODO: Remove references to 'fadump_reserve_mem=' parameter,
670 * the sooner 'crashkernel=' parameter is accustomed to.
672 static int __init early_fadump_reserve_mem(char *p)
675 fw_dump.reserve_bootvar = memparse(p, &p);
678 early_param("fadump_reserve_mem", early_fadump_reserve_mem);
680 void crash_fadump(struct pt_regs *regs, const char *str)
683 struct fadump_crash_info_header *fdh = NULL;
684 int old_cpu, this_cpu;
685 /* Do not include first CPU */
686 unsigned int ncpus = num_online_cpus() - 1;
688 if (!should_fadump_crash())
692 * old_cpu == -1 means this is the first CPU which has come here,
693 * go ahead and trigger fadump.
695 * old_cpu != -1 means some other CPU has already on it's way
696 * to trigger fadump, just keep looping here.
698 this_cpu = smp_processor_id();
699 old_cpu = cmpxchg(&crashing_cpu, -1, this_cpu);
702 atomic_inc(&cpus_in_fadump);
705 * We can't loop here indefinitely. Wait as long as fadump
706 * is in force. If we race with fadump un-registration this
707 * loop will break and then we go down to normal panic path
708 * and reboot. If fadump is in force the first crashing
709 * cpu will definitely trigger fadump.
711 while (fw_dump.dump_registered)
716 fdh = __va(fw_dump.fadumphdr_addr);
717 fdh->crashing_cpu = crashing_cpu;
718 crash_save_vmcoreinfo();
723 ppc_save_regs(&fdh->regs);
725 fdh->online_mask = *cpu_online_mask;
728 * If we came in via system reset, wait a while for the secondary
731 if (TRAP(&(fdh->regs)) == INTERRUPT_SYSTEM_RESET) {
732 msecs = CRASH_TIMEOUT;
733 while ((atomic_read(&cpus_in_fadump) < ncpus) && (--msecs > 0))
737 fw_dump.ops->fadump_trigger(fdh, str);
740 u32 *fadump_regs_to_elf_notes(u32 *buf, struct pt_regs *regs)
742 struct elf_prstatus prstatus;
744 memset(&prstatus, 0, sizeof(prstatus));
746 * FIXME: How do i get PID? Do I really need it?
747 * prstatus.pr_pid = ????
749 elf_core_copy_kernel_regs(&prstatus.pr_reg, regs);
750 buf = append_elf_note(buf, CRASH_CORE_NOTE_NAME, NT_PRSTATUS,
751 &prstatus, sizeof(prstatus));
755 void fadump_update_elfcore_header(char *bufp)
757 struct elf_phdr *phdr;
759 bufp += sizeof(struct elfhdr);
761 /* First note is a place holder for cpu notes info. */
762 phdr = (struct elf_phdr *)bufp;
764 if (phdr->p_type == PT_NOTE) {
765 phdr->p_paddr = __pa(fw_dump.cpu_notes_buf_vaddr);
766 phdr->p_offset = phdr->p_paddr;
767 phdr->p_filesz = fw_dump.cpu_notes_buf_size;
768 phdr->p_memsz = fw_dump.cpu_notes_buf_size;
773 static void *fadump_alloc_buffer(unsigned long size)
775 unsigned long count, i;
779 vaddr = alloc_pages_exact(size, GFP_KERNEL | __GFP_ZERO);
783 count = PAGE_ALIGN(size) / PAGE_SIZE;
784 page = virt_to_page(vaddr);
785 for (i = 0; i < count; i++)
786 mark_page_reserved(page + i);
790 static void fadump_free_buffer(unsigned long vaddr, unsigned long size)
792 free_reserved_area((void *)vaddr, (void *)(vaddr + size), -1, NULL);
795 s32 fadump_setup_cpu_notes_buf(u32 num_cpus)
797 /* Allocate buffer to hold cpu crash notes. */
798 fw_dump.cpu_notes_buf_size = num_cpus * sizeof(note_buf_t);
799 fw_dump.cpu_notes_buf_size = PAGE_ALIGN(fw_dump.cpu_notes_buf_size);
800 fw_dump.cpu_notes_buf_vaddr =
801 (unsigned long)fadump_alloc_buffer(fw_dump.cpu_notes_buf_size);
802 if (!fw_dump.cpu_notes_buf_vaddr) {
803 pr_err("Failed to allocate %ld bytes for CPU notes buffer\n",
804 fw_dump.cpu_notes_buf_size);
808 pr_debug("Allocated buffer for cpu notes of size %ld at 0x%lx\n",
809 fw_dump.cpu_notes_buf_size,
810 fw_dump.cpu_notes_buf_vaddr);
814 void fadump_free_cpu_notes_buf(void)
816 if (!fw_dump.cpu_notes_buf_vaddr)
819 fadump_free_buffer(fw_dump.cpu_notes_buf_vaddr,
820 fw_dump.cpu_notes_buf_size);
821 fw_dump.cpu_notes_buf_vaddr = 0;
822 fw_dump.cpu_notes_buf_size = 0;
825 static void fadump_free_mem_ranges(struct fadump_mrange_info *mrange_info)
827 if (mrange_info->is_static) {
828 mrange_info->mem_range_cnt = 0;
832 kfree(mrange_info->mem_ranges);
833 memset((void *)((u64)mrange_info + RNG_NAME_SZ), 0,
834 (sizeof(struct fadump_mrange_info) - RNG_NAME_SZ));
838 * Allocate or reallocate mem_ranges array in incremental units
841 static int fadump_alloc_mem_ranges(struct fadump_mrange_info *mrange_info)
843 struct fadump_memory_range *new_array;
846 new_size = mrange_info->mem_ranges_sz + PAGE_SIZE;
847 pr_debug("Allocating %llu bytes of memory for %s memory ranges\n",
848 new_size, mrange_info->name);
850 new_array = krealloc(mrange_info->mem_ranges, new_size, GFP_KERNEL);
851 if (new_array == NULL) {
852 pr_err("Insufficient memory for setting up %s memory ranges\n",
854 fadump_free_mem_ranges(mrange_info);
858 mrange_info->mem_ranges = new_array;
859 mrange_info->mem_ranges_sz = new_size;
860 mrange_info->max_mem_ranges = (new_size /
861 sizeof(struct fadump_memory_range));
864 static inline int fadump_add_mem_range(struct fadump_mrange_info *mrange_info,
867 struct fadump_memory_range *mem_ranges = mrange_info->mem_ranges;
868 bool is_adjacent = false;
875 * Fold adjacent memory ranges to bring down the memory ranges/
876 * PT_LOAD segments count.
878 if (mrange_info->mem_range_cnt) {
879 start = mem_ranges[mrange_info->mem_range_cnt - 1].base;
880 size = mem_ranges[mrange_info->mem_range_cnt - 1].size;
883 * Boot memory area needs separate PT_LOAD segment(s) as it
884 * is moved to a different location at the time of crash.
885 * So, fold only if the region is not boot memory area.
887 if ((start + size) == base && start >= fw_dump.boot_mem_top)
891 /* resize the array on reaching the limit */
892 if (mrange_info->mem_range_cnt == mrange_info->max_mem_ranges) {
895 if (mrange_info->is_static) {
896 pr_err("Reached array size limit for %s memory ranges\n",
901 ret = fadump_alloc_mem_ranges(mrange_info);
905 /* Update to the new resized array */
906 mem_ranges = mrange_info->mem_ranges;
910 mem_ranges[mrange_info->mem_range_cnt].base = start;
911 mrange_info->mem_range_cnt++;
914 mem_ranges[mrange_info->mem_range_cnt - 1].size = (end - start);
915 pr_debug("%s_memory_range[%d] [%#016llx-%#016llx], %#llx bytes\n",
916 mrange_info->name, (mrange_info->mem_range_cnt - 1),
917 start, end - 1, (end - start));
921 static int fadump_exclude_reserved_area(u64 start, u64 end)
923 u64 ra_start, ra_end;
926 ra_start = fw_dump.reserve_dump_area_start;
927 ra_end = ra_start + fw_dump.reserve_dump_area_size;
929 if ((ra_start < end) && (ra_end > start)) {
930 if ((start < ra_start) && (end > ra_end)) {
931 ret = fadump_add_mem_range(&crash_mrange_info,
936 ret = fadump_add_mem_range(&crash_mrange_info,
938 } else if (start < ra_start) {
939 ret = fadump_add_mem_range(&crash_mrange_info,
941 } else if (ra_end < end) {
942 ret = fadump_add_mem_range(&crash_mrange_info,
946 ret = fadump_add_mem_range(&crash_mrange_info, start, end);
951 static int fadump_init_elfcore_header(char *bufp)
955 elf = (struct elfhdr *) bufp;
956 bufp += sizeof(struct elfhdr);
957 memcpy(elf->e_ident, ELFMAG, SELFMAG);
958 elf->e_ident[EI_CLASS] = ELF_CLASS;
959 elf->e_ident[EI_DATA] = ELF_DATA;
960 elf->e_ident[EI_VERSION] = EV_CURRENT;
961 elf->e_ident[EI_OSABI] = ELF_OSABI;
962 memset(elf->e_ident+EI_PAD, 0, EI_NIDENT-EI_PAD);
963 elf->e_type = ET_CORE;
964 elf->e_machine = ELF_ARCH;
965 elf->e_version = EV_CURRENT;
967 elf->e_phoff = sizeof(struct elfhdr);
969 #if defined(_CALL_ELF)
970 elf->e_flags = _CALL_ELF;
974 elf->e_ehsize = sizeof(struct elfhdr);
975 elf->e_phentsize = sizeof(struct elf_phdr);
977 elf->e_shentsize = 0;
985 * Traverse through memblock structure and setup crash memory ranges. These
986 * ranges will be used create PT_LOAD program headers in elfcore header.
988 static int fadump_setup_crash_memory_ranges(void)
993 pr_debug("Setup crash memory ranges.\n");
994 crash_mrange_info.mem_range_cnt = 0;
997 * Boot memory region(s) registered with firmware are moved to
998 * different location at the time of crash. Create separate program
999 * header(s) for this memory chunk(s) with the correct offset.
1001 for (i = 0; i < fw_dump.boot_mem_regs_cnt; i++) {
1002 start = fw_dump.boot_mem_addr[i];
1003 end = start + fw_dump.boot_mem_sz[i];
1004 ret = fadump_add_mem_range(&crash_mrange_info, start, end);
1009 for_each_mem_range(i, &start, &end) {
1011 * skip the memory chunk that is already added
1012 * (0 through boot_memory_top).
1014 if (start < fw_dump.boot_mem_top) {
1015 if (end > fw_dump.boot_mem_top)
1016 start = fw_dump.boot_mem_top;
1021 /* add this range excluding the reserved dump area. */
1022 ret = fadump_exclude_reserved_area(start, end);
1031 * If the given physical address falls within the boot memory region then
1032 * return the relocated address that points to the dump region reserved
1033 * for saving initial boot memory contents.
1035 static inline unsigned long fadump_relocate(unsigned long paddr)
1037 unsigned long raddr, rstart, rend, rlast, hole_size;
1043 for (i = 0; i < fw_dump.boot_mem_regs_cnt; i++) {
1044 rstart = fw_dump.boot_mem_addr[i];
1045 rend = rstart + fw_dump.boot_mem_sz[i];
1046 hole_size += (rstart - rlast);
1048 if (paddr >= rstart && paddr < rend) {
1049 raddr += fw_dump.boot_mem_dest_addr - hole_size;
1056 pr_debug("vmcoreinfo: paddr = 0x%lx, raddr = 0x%lx\n", paddr, raddr);
1060 static int fadump_create_elfcore_headers(char *bufp)
1062 unsigned long long raddr, offset;
1063 struct elf_phdr *phdr;
1067 fadump_init_elfcore_header(bufp);
1068 elf = (struct elfhdr *)bufp;
1069 bufp += sizeof(struct elfhdr);
1072 * setup ELF PT_NOTE, place holder for cpu notes info. The notes info
1073 * will be populated during second kernel boot after crash. Hence
1074 * this PT_NOTE will always be the first elf note.
1076 * NOTE: Any new ELF note addition should be placed after this note.
1078 phdr = (struct elf_phdr *)bufp;
1079 bufp += sizeof(struct elf_phdr);
1080 phdr->p_type = PT_NOTE;
1092 /* setup ELF PT_NOTE for vmcoreinfo */
1093 phdr = (struct elf_phdr *)bufp;
1094 bufp += sizeof(struct elf_phdr);
1095 phdr->p_type = PT_NOTE;
1100 phdr->p_paddr = fadump_relocate(paddr_vmcoreinfo_note());
1101 phdr->p_offset = phdr->p_paddr;
1102 phdr->p_memsz = phdr->p_filesz = VMCOREINFO_NOTE_SIZE;
1104 /* Increment number of program headers. */
1107 /* setup PT_LOAD sections. */
1110 raddr = fw_dump.boot_mem_addr[0];
1111 for (i = 0; i < crash_mrange_info.mem_range_cnt; i++) {
1114 mbase = crash_mrange_info.mem_ranges[i].base;
1115 msize = crash_mrange_info.mem_ranges[i].size;
1119 phdr = (struct elf_phdr *)bufp;
1120 bufp += sizeof(struct elf_phdr);
1121 phdr->p_type = PT_LOAD;
1122 phdr->p_flags = PF_R|PF_W|PF_X;
1123 phdr->p_offset = mbase;
1125 if (mbase == raddr) {
1127 * The entire real memory region will be moved by
1128 * firmware to the specified destination_address.
1129 * Hence set the correct offset.
1131 phdr->p_offset = fw_dump.boot_mem_dest_addr + offset;
1132 if (j < (fw_dump.boot_mem_regs_cnt - 1)) {
1133 offset += fw_dump.boot_mem_sz[j];
1134 raddr = fw_dump.boot_mem_addr[++j];
1138 phdr->p_paddr = mbase;
1139 phdr->p_vaddr = (unsigned long)__va(mbase);
1140 phdr->p_filesz = msize;
1141 phdr->p_memsz = msize;
1144 /* Increment number of program headers. */
1150 static unsigned long init_fadump_header(unsigned long addr)
1152 struct fadump_crash_info_header *fdh;
1158 addr += sizeof(struct fadump_crash_info_header);
1160 memset(fdh, 0, sizeof(struct fadump_crash_info_header));
1161 fdh->magic_number = FADUMP_CRASH_INFO_MAGIC;
1162 fdh->elfcorehdr_addr = addr;
1163 /* We will set the crashing cpu id in crash_fadump() during crash. */
1164 fdh->crashing_cpu = FADUMP_CPU_UNKNOWN;
1169 static int register_fadump(void)
1176 * If no memory is reserved then we can not register for firmware-
1179 if (!fw_dump.reserve_dump_area_size)
1182 ret = fadump_setup_crash_memory_ranges();
1186 addr = fw_dump.fadumphdr_addr;
1188 /* Initialize fadump crash info header. */
1189 addr = init_fadump_header(addr);
1192 pr_debug("Creating ELF core headers at %#016lx\n", addr);
1193 fadump_create_elfcore_headers(vaddr);
1195 /* register the future kernel dump with firmware. */
1196 pr_debug("Registering for firmware-assisted kernel dump...\n");
1197 return fw_dump.ops->fadump_register(&fw_dump);
1200 void fadump_cleanup(void)
1202 if (!fw_dump.fadump_supported)
1205 /* Invalidate the registration only if dump is active. */
1206 if (fw_dump.dump_active) {
1207 pr_debug("Invalidating firmware-assisted dump registration\n");
1208 fw_dump.ops->fadump_invalidate(&fw_dump);
1209 } else if (fw_dump.dump_registered) {
1210 /* Un-register Firmware-assisted dump if it was registered. */
1211 fw_dump.ops->fadump_unregister(&fw_dump);
1212 fadump_free_mem_ranges(&crash_mrange_info);
1215 if (fw_dump.ops->fadump_cleanup)
1216 fw_dump.ops->fadump_cleanup(&fw_dump);
1219 static void fadump_free_reserved_memory(unsigned long start_pfn,
1220 unsigned long end_pfn)
1223 unsigned long time_limit = jiffies + HZ;
1225 pr_info("freeing reserved memory (0x%llx - 0x%llx)\n",
1226 PFN_PHYS(start_pfn), PFN_PHYS(end_pfn));
1228 for (pfn = start_pfn; pfn < end_pfn; pfn++) {
1229 free_reserved_page(pfn_to_page(pfn));
1231 if (time_after(jiffies, time_limit)) {
1233 time_limit = jiffies + HZ;
1239 * Skip memory holes and free memory that was actually reserved.
1241 static void fadump_release_reserved_area(u64 start, u64 end)
1243 unsigned long reg_spfn, reg_epfn;
1244 u64 tstart, tend, spfn, epfn;
1247 spfn = PHYS_PFN(start);
1248 epfn = PHYS_PFN(end);
1250 for_each_mem_pfn_range(i, MAX_NUMNODES, ®_spfn, ®_epfn, NULL) {
1251 tstart = max_t(u64, spfn, reg_spfn);
1252 tend = min_t(u64, epfn, reg_epfn);
1254 if (tstart < tend) {
1255 fadump_free_reserved_memory(tstart, tend);
1266 * Sort the mem ranges in-place and merge adjacent ranges
1267 * to minimize the memory ranges count.
1269 static void sort_and_merge_mem_ranges(struct fadump_mrange_info *mrange_info)
1271 struct fadump_memory_range *mem_ranges;
1272 struct fadump_memory_range tmp_range;
1276 if (!reserved_mrange_info.mem_range_cnt)
1279 /* Sort the memory ranges */
1280 mem_ranges = mrange_info->mem_ranges;
1281 for (i = 0; i < mrange_info->mem_range_cnt; i++) {
1283 for (j = (i + 1); j < mrange_info->mem_range_cnt; j++) {
1284 if (mem_ranges[idx].base > mem_ranges[j].base)
1288 tmp_range = mem_ranges[idx];
1289 mem_ranges[idx] = mem_ranges[i];
1290 mem_ranges[i] = tmp_range;
1294 /* Merge adjacent reserved ranges */
1296 for (i = 1; i < mrange_info->mem_range_cnt; i++) {
1297 base = mem_ranges[i-1].base;
1298 size = mem_ranges[i-1].size;
1299 if (mem_ranges[i].base == (base + size))
1300 mem_ranges[idx].size += mem_ranges[i].size;
1306 mem_ranges[idx] = mem_ranges[i];
1309 mrange_info->mem_range_cnt = idx + 1;
1313 * Scan reserved-ranges to consider them while reserving/releasing
1314 * memory for FADump.
1316 static void __init early_init_dt_scan_reserved_ranges(unsigned long node)
1322 /* reserved-ranges already scanned */
1323 if (reserved_mrange_info.mem_range_cnt != 0)
1326 prop = of_get_flat_dt_prop(node, "reserved-ranges", &len);
1331 * Each reserved range is an (address,size) pair, 2 cells each,
1332 * totalling 4 cells per range.
1334 for (i = 0; i < len / (sizeof(*prop) * 4); i++) {
1337 base = of_read_number(prop + (i * 4) + 0, 2);
1338 size = of_read_number(prop + (i * 4) + 2, 2);
1341 ret = fadump_add_mem_range(&reserved_mrange_info,
1344 pr_warn("some reserved ranges are ignored!\n");
1350 /* Compact reserved ranges */
1351 sort_and_merge_mem_ranges(&reserved_mrange_info);
1355 * Release the memory that was reserved during early boot to preserve the
1356 * crash'ed kernel's memory contents except reserved dump area (permanent
1357 * reservation) and reserved ranges used by F/W. The released memory will
1358 * be available for general use.
1360 static void fadump_release_memory(u64 begin, u64 end)
1362 u64 ra_start, ra_end, tstart;
1365 ra_start = fw_dump.reserve_dump_area_start;
1366 ra_end = ra_start + fw_dump.reserve_dump_area_size;
1369 * If reserved ranges array limit is hit, overwrite the last reserved
1370 * memory range with reserved dump area to ensure it is excluded from
1371 * the memory being released (reused for next FADump registration).
1373 if (reserved_mrange_info.mem_range_cnt ==
1374 reserved_mrange_info.max_mem_ranges)
1375 reserved_mrange_info.mem_range_cnt--;
1377 ret = fadump_add_mem_range(&reserved_mrange_info, ra_start, ra_end);
1381 /* Get the reserved ranges list in order first. */
1382 sort_and_merge_mem_ranges(&reserved_mrange_info);
1384 /* Exclude reserved ranges and release remaining memory */
1386 for (i = 0; i < reserved_mrange_info.mem_range_cnt; i++) {
1387 ra_start = reserved_mrange_info.mem_ranges[i].base;
1388 ra_end = ra_start + reserved_mrange_info.mem_ranges[i].size;
1390 if (tstart >= ra_end)
1393 if (tstart < ra_start)
1394 fadump_release_reserved_area(tstart, ra_start);
1399 fadump_release_reserved_area(tstart, end);
1402 static void fadump_invalidate_release_mem(void)
1404 mutex_lock(&fadump_mutex);
1405 if (!fw_dump.dump_active) {
1406 mutex_unlock(&fadump_mutex);
1411 mutex_unlock(&fadump_mutex);
1413 fadump_release_memory(fw_dump.boot_mem_top, memblock_end_of_DRAM());
1414 fadump_free_cpu_notes_buf();
1417 * Setup kernel metadata and initialize the kernel dump
1418 * memory structure for FADump re-registration.
1420 if (fw_dump.ops->fadump_setup_metadata &&
1421 (fw_dump.ops->fadump_setup_metadata(&fw_dump) < 0))
1422 pr_warn("Failed to setup kernel metadata!\n");
1423 fw_dump.ops->fadump_init_mem_struct(&fw_dump);
1426 static ssize_t release_mem_store(struct kobject *kobj,
1427 struct kobj_attribute *attr,
1428 const char *buf, size_t count)
1432 if (!fw_dump.dump_active)
1435 if (kstrtoint(buf, 0, &input))
1440 * Take away the '/proc/vmcore'. We are releasing the dump
1441 * memory, hence it will not be valid anymore.
1443 #ifdef CONFIG_PROC_VMCORE
1446 fadump_invalidate_release_mem();
1453 /* Release the reserved memory and disable the FADump */
1454 static void unregister_fadump(void)
1457 fadump_release_memory(fw_dump.reserve_dump_area_start,
1458 fw_dump.reserve_dump_area_size);
1459 fw_dump.fadump_enabled = 0;
1460 kobject_put(fadump_kobj);
1463 static ssize_t enabled_show(struct kobject *kobj,
1464 struct kobj_attribute *attr,
1467 return sprintf(buf, "%d\n", fw_dump.fadump_enabled);
1470 static ssize_t mem_reserved_show(struct kobject *kobj,
1471 struct kobj_attribute *attr,
1474 return sprintf(buf, "%ld\n", fw_dump.reserve_dump_area_size);
1477 static ssize_t registered_show(struct kobject *kobj,
1478 struct kobj_attribute *attr,
1481 return sprintf(buf, "%d\n", fw_dump.dump_registered);
1484 static ssize_t registered_store(struct kobject *kobj,
1485 struct kobj_attribute *attr,
1486 const char *buf, size_t count)
1491 if (!fw_dump.fadump_enabled || fw_dump.dump_active)
1494 if (kstrtoint(buf, 0, &input))
1497 mutex_lock(&fadump_mutex);
1501 if (fw_dump.dump_registered == 0) {
1505 /* Un-register Firmware-assisted dump */
1506 pr_debug("Un-register firmware-assisted dump\n");
1507 fw_dump.ops->fadump_unregister(&fw_dump);
1510 if (fw_dump.dump_registered == 1) {
1511 /* Un-register Firmware-assisted dump */
1512 fw_dump.ops->fadump_unregister(&fw_dump);
1514 /* Register Firmware-assisted dump */
1515 ret = register_fadump();
1523 mutex_unlock(&fadump_mutex);
1524 return ret < 0 ? ret : count;
1527 static int fadump_region_show(struct seq_file *m, void *private)
1529 if (!fw_dump.fadump_enabled)
1532 mutex_lock(&fadump_mutex);
1533 fw_dump.ops->fadump_region_show(&fw_dump, m);
1534 mutex_unlock(&fadump_mutex);
1538 static struct kobj_attribute release_attr = __ATTR_WO(release_mem);
1539 static struct kobj_attribute enable_attr = __ATTR_RO(enabled);
1540 static struct kobj_attribute register_attr = __ATTR_RW(registered);
1541 static struct kobj_attribute mem_reserved_attr = __ATTR_RO(mem_reserved);
1543 static struct attribute *fadump_attrs[] = {
1545 ®ister_attr.attr,
1546 &mem_reserved_attr.attr,
1550 ATTRIBUTE_GROUPS(fadump);
1552 DEFINE_SHOW_ATTRIBUTE(fadump_region);
1554 static void fadump_init_files(void)
1558 fadump_kobj = kobject_create_and_add("fadump", kernel_kobj);
1560 pr_err("failed to create fadump kobject\n");
1564 debugfs_create_file("fadump_region", 0444, arch_debugfs_dir, NULL,
1565 &fadump_region_fops);
1567 if (fw_dump.dump_active) {
1568 rc = sysfs_create_file(fadump_kobj, &release_attr.attr);
1570 pr_err("unable to create release_mem sysfs file (%d)\n",
1574 rc = sysfs_create_groups(fadump_kobj, fadump_groups);
1576 pr_err("sysfs group creation failed (%d), unregistering FADump",
1578 unregister_fadump();
1583 * The FADump sysfs are moved from kernel_kobj to fadump_kobj need to
1584 * create symlink at old location to maintain backward compatibility.
1586 * - fadump_enabled -> fadump/enabled
1587 * - fadump_registered -> fadump/registered
1588 * - fadump_release_mem -> fadump/release_mem
1590 rc = compat_only_sysfs_link_entry_to_kobj(kernel_kobj, fadump_kobj,
1591 "enabled", "fadump_enabled");
1593 pr_err("unable to create fadump_enabled symlink (%d)", rc);
1597 rc = compat_only_sysfs_link_entry_to_kobj(kernel_kobj, fadump_kobj,
1599 "fadump_registered");
1601 pr_err("unable to create fadump_registered symlink (%d)", rc);
1602 sysfs_remove_link(kernel_kobj, "fadump_enabled");
1606 if (fw_dump.dump_active) {
1607 rc = compat_only_sysfs_link_entry_to_kobj(kernel_kobj,
1610 "fadump_release_mem");
1612 pr_err("unable to create fadump_release_mem symlink (%d)",
1619 * Prepare for firmware-assisted dump.
1621 int __init setup_fadump(void)
1623 if (!fw_dump.fadump_supported)
1626 fadump_init_files();
1627 fadump_show_config();
1629 if (!fw_dump.fadump_enabled)
1633 * If dump data is available then see if it is valid and prepare for
1634 * saving it to the disk.
1636 if (fw_dump.dump_active) {
1638 * if dump process fails then invalidate the registration
1639 * and release memory before proceeding for re-registration.
1641 if (fw_dump.ops->fadump_process(&fw_dump) < 0)
1642 fadump_invalidate_release_mem();
1644 /* Initialize the kernel dump memory structure for FAD registration. */
1645 else if (fw_dump.reserve_dump_area_size)
1646 fw_dump.ops->fadump_init_mem_struct(&fw_dump);
1649 * In case of panic, fadump is triggered via ppc_panic_event()
1650 * panic notifier. Setting crash_kexec_post_notifiers to 'true'
1651 * lets panic() function take crash friendly path before panic
1652 * notifiers are invoked.
1654 crash_kexec_post_notifiers = true;
1658 subsys_initcall(setup_fadump);
1659 #else /* !CONFIG_PRESERVE_FA_DUMP */
1661 /* Scan the Firmware Assisted dump configuration details. */
1662 int __init early_init_dt_scan_fw_dump(unsigned long node, const char *uname,
1663 int depth, void *data)
1665 if ((depth != 1) || (strcmp(uname, "ibm,opal") != 0))
1668 opal_fadump_dt_scan(&fw_dump, node);
1673 * When dump is active but PRESERVE_FA_DUMP is enabled on the kernel,
1674 * preserve crash data. The subsequent memory preserving kernel boot
1675 * is likely to process this crash data.
1677 int __init fadump_reserve_mem(void)
1679 if (fw_dump.dump_active) {
1681 * If last boot has crashed then reserve all the memory
1682 * above boot memory to preserve crash data.
1684 pr_info("Preserving crash data for processing in next boot.\n");
1685 fadump_reserve_crash_area(fw_dump.boot_mem_top);
1687 pr_debug("FADump-aware kernel..\n");
1691 #endif /* CONFIG_PRESERVE_FA_DUMP */
1693 /* Preserve everything above the base address */
1694 static void __init fadump_reserve_crash_area(u64 base)
1696 u64 i, mstart, mend, msize;
1698 for_each_mem_range(i, &mstart, &mend) {
1699 msize = mend - mstart;
1701 if ((mstart + msize) < base)
1704 if (mstart < base) {
1705 msize -= (base - mstart);
1709 pr_info("Reserving %lluMB of memory at %#016llx for preserving crash data",
1710 (msize >> 20), mstart);
1711 memblock_reserve(mstart, msize);
1715 unsigned long __init arch_reserved_kernel_pages(void)
1717 return memblock_reserved_size() / PAGE_SIZE;