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-rw-r--r--arch/powerpc/platforms/powernv/opal-fadump.c716
1 files changed, 716 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/powernv/opal-fadump.c b/arch/powerpc/platforms/powernv/opal-fadump.c
new file mode 100644
index 000000000000..d361d37d975f
--- /dev/null
+++ b/arch/powerpc/platforms/powernv/opal-fadump.c
@@ -0,0 +1,716 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Firmware-Assisted Dump support on POWER platform (OPAL).
+ *
+ * Copyright 2019, Hari Bathini, IBM Corporation.
+ */
+
+#define pr_fmt(fmt) "opal fadump: " fmt
+
+#include <linux/string.h>
+#include <linux/seq_file.h>
+#include <linux/of.h>
+#include <linux/of_fdt.h>
+#include <linux/libfdt.h>
+#include <linux/mm.h>
+#include <linux/crash_dump.h>
+
+#include <asm/page.h>
+#include <asm/opal.h>
+#include <asm/fadump-internal.h>
+
+#include "opal-fadump.h"
+
+
+#ifdef CONFIG_PRESERVE_FA_DUMP
+/*
+ * When dump is active but PRESERVE_FA_DUMP is enabled on the kernel,
+ * ensure crash data is preserved in hope that the subsequent memory
+ * preserving kernel boot is going to process this crash data.
+ */
+void __init opal_fadump_dt_scan(struct fw_dump *fadump_conf, u64 node)
+{
+ const struct opal_fadump_mem_struct *opal_fdm_active;
+ const __be32 *prop;
+ unsigned long dn;
+ u64 addr = 0;
+ s64 ret;
+
+ dn = of_get_flat_dt_subnode_by_name(node, "dump");
+ if (dn == -FDT_ERR_NOTFOUND)
+ return;
+
+ /*
+ * Check if dump has been initiated on last reboot.
+ */
+ prop = of_get_flat_dt_prop(dn, "mpipl-boot", NULL);
+ if (!prop)
+ return;
+
+ ret = opal_mpipl_query_tag(OPAL_MPIPL_TAG_KERNEL, &addr);
+ if ((ret != OPAL_SUCCESS) || !addr) {
+ pr_debug("Could not get Kernel metadata (%lld)\n", ret);
+ return;
+ }
+
+ /*
+ * Preserve memory only if kernel memory regions are registered
+ * with f/w for MPIPL.
+ */
+ addr = be64_to_cpu(addr);
+ pr_debug("Kernel metadata addr: %llx\n", addr);
+ opal_fdm_active = (void *)addr;
+ if (opal_fdm_active->registered_regions == 0)
+ return;
+
+ ret = opal_mpipl_query_tag(OPAL_MPIPL_TAG_BOOT_MEM, &addr);
+ if ((ret != OPAL_SUCCESS) || !addr) {
+ pr_err("Failed to get boot memory tag (%lld)\n", ret);
+ return;
+ }
+
+ /*
+ * Memory below this address can be used for booting a
+ * capture kernel or petitboot kernel. Preserve everything
+ * above this address for processing crashdump.
+ */
+ fadump_conf->boot_mem_top = be64_to_cpu(addr);
+ pr_debug("Preserve everything above %llx\n", fadump_conf->boot_mem_top);
+
+ pr_info("Firmware-assisted dump is active.\n");
+ fadump_conf->dump_active = 1;
+}
+
+#else /* CONFIG_PRESERVE_FA_DUMP */
+static const struct opal_fadump_mem_struct *opal_fdm_active;
+static const struct opal_mpipl_fadump *opal_cpu_metadata;
+static struct opal_fadump_mem_struct *opal_fdm;
+
+#ifdef CONFIG_OPAL_CORE
+extern bool kernel_initiated;
+#endif
+
+static int opal_fadump_unregister(struct fw_dump *fadump_conf);
+
+static void opal_fadump_update_config(struct fw_dump *fadump_conf,
+ const struct opal_fadump_mem_struct *fdm)
+{
+ pr_debug("Boot memory regions count: %d\n", fdm->region_cnt);
+
+ /*
+ * The destination address of the first boot memory region is the
+ * destination address of boot memory regions.
+ */
+ fadump_conf->boot_mem_dest_addr = fdm->rgn[0].dest;
+ pr_debug("Destination address of boot memory regions: %#016llx\n",
+ fadump_conf->boot_mem_dest_addr);
+
+ fadump_conf->fadumphdr_addr = fdm->fadumphdr_addr;
+}
+
+/*
+ * This function is called in the capture kernel to get configuration details
+ * from metadata setup by the first kernel.
+ */
+static void opal_fadump_get_config(struct fw_dump *fadump_conf,
+ const struct opal_fadump_mem_struct *fdm)
+{
+ unsigned long base, size, last_end, hole_size;
+ int i;
+
+ if (!fadump_conf->dump_active)
+ return;
+
+ last_end = 0;
+ hole_size = 0;
+ fadump_conf->boot_memory_size = 0;
+
+ pr_debug("Boot memory regions:\n");
+ for (i = 0; i < fdm->region_cnt; i++) {
+ base = fdm->rgn[i].src;
+ size = fdm->rgn[i].size;
+ pr_debug("\t[%03d] base: 0x%lx, size: 0x%lx\n", i, base, size);
+
+ fadump_conf->boot_mem_addr[i] = base;
+ fadump_conf->boot_mem_sz[i] = size;
+ fadump_conf->boot_memory_size += size;
+ hole_size += (base - last_end);
+
+ last_end = base + size;
+ }
+
+ /*
+ * Start address of reserve dump area (permanent reservation) for
+ * re-registering FADump after dump capture.
+ */
+ fadump_conf->reserve_dump_area_start = fdm->rgn[0].dest;
+
+ /*
+ * Rarely, but it can so happen that system crashes before all
+ * boot memory regions are registered for MPIPL. In such
+ * cases, warn that the vmcore may not be accurate and proceed
+ * anyway as that is the best bet considering free pages, cache
+ * pages, user pages, etc are usually filtered out.
+ *
+ * Hope the memory that could not be preserved only has pages
+ * that are usually filtered out while saving the vmcore.
+ */
+ if (fdm->region_cnt > fdm->registered_regions) {
+ pr_warn("Not all memory regions were saved!!!\n");
+ pr_warn(" Unsaved memory regions:\n");
+ i = fdm->registered_regions;
+ while (i < fdm->region_cnt) {
+ pr_warn("\t[%03d] base: 0x%llx, size: 0x%llx\n",
+ i, fdm->rgn[i].src, fdm->rgn[i].size);
+ i++;
+ }
+
+ pr_warn("If the unsaved regions only contain pages that are filtered out (eg. free/user pages), the vmcore should still be usable.\n");
+ pr_warn("WARNING: If the unsaved regions contain kernel pages, the vmcore will be corrupted.\n");
+ }
+
+ fadump_conf->boot_mem_top = (fadump_conf->boot_memory_size + hole_size);
+ fadump_conf->boot_mem_regs_cnt = fdm->region_cnt;
+ opal_fadump_update_config(fadump_conf, fdm);
+}
+
+/* Initialize kernel metadata */
+static void opal_fadump_init_metadata(struct opal_fadump_mem_struct *fdm)
+{
+ fdm->version = OPAL_FADUMP_VERSION;
+ fdm->region_cnt = 0;
+ fdm->registered_regions = 0;
+ fdm->fadumphdr_addr = 0;
+}
+
+static u64 opal_fadump_init_mem_struct(struct fw_dump *fadump_conf)
+{
+ u64 addr = fadump_conf->reserve_dump_area_start;
+ int i;
+
+ opal_fdm = __va(fadump_conf->kernel_metadata);
+ opal_fadump_init_metadata(opal_fdm);
+
+ /* Boot memory regions */
+ for (i = 0; i < fadump_conf->boot_mem_regs_cnt; i++) {
+ opal_fdm->rgn[i].src = fadump_conf->boot_mem_addr[i];
+ opal_fdm->rgn[i].dest = addr;
+ opal_fdm->rgn[i].size = fadump_conf->boot_mem_sz[i];
+
+ opal_fdm->region_cnt++;
+ addr += fadump_conf->boot_mem_sz[i];
+ }
+
+ /*
+ * Kernel metadata is passed to f/w and retrieved in capture kerenl.
+ * So, use it to save fadump header address instead of calculating it.
+ */
+ opal_fdm->fadumphdr_addr = (opal_fdm->rgn[0].dest +
+ fadump_conf->boot_memory_size);
+
+ opal_fadump_update_config(fadump_conf, opal_fdm);
+
+ return addr;
+}
+
+static u64 opal_fadump_get_metadata_size(void)
+{
+ return PAGE_ALIGN(sizeof(struct opal_fadump_mem_struct));
+}
+
+static int opal_fadump_setup_metadata(struct fw_dump *fadump_conf)
+{
+ int err = 0;
+ s64 ret;
+
+ /*
+ * Use the last page(s) in FADump memory reservation for
+ * kernel metadata.
+ */
+ fadump_conf->kernel_metadata = (fadump_conf->reserve_dump_area_start +
+ fadump_conf->reserve_dump_area_size -
+ opal_fadump_get_metadata_size());
+ pr_info("Kernel metadata addr: %llx\n", fadump_conf->kernel_metadata);
+
+ /* Initialize kernel metadata before registering the address with f/w */
+ opal_fdm = __va(fadump_conf->kernel_metadata);
+ opal_fadump_init_metadata(opal_fdm);
+
+ /*
+ * Register metadata address with f/w. Can be retrieved in
+ * the capture kernel.
+ */
+ ret = opal_mpipl_register_tag(OPAL_MPIPL_TAG_KERNEL,
+ fadump_conf->kernel_metadata);
+ if (ret != OPAL_SUCCESS) {
+ pr_err("Failed to set kernel metadata tag!\n");
+ err = -EPERM;
+ }
+
+ /*
+ * Register boot memory top address with f/w. Should be retrieved
+ * by a kernel that intends to preserve crash'ed kernel's memory.
+ */
+ ret = opal_mpipl_register_tag(OPAL_MPIPL_TAG_BOOT_MEM,
+ fadump_conf->boot_mem_top);
+ if (ret != OPAL_SUCCESS) {
+ pr_err("Failed to set boot memory tag!\n");
+ err = -EPERM;
+ }
+
+ return err;
+}
+
+static u64 opal_fadump_get_bootmem_min(void)
+{
+ return OPAL_FADUMP_MIN_BOOT_MEM;
+}
+
+static int opal_fadump_register(struct fw_dump *fadump_conf)
+{
+ s64 rc = OPAL_PARAMETER;
+ int i, err = -EIO;
+
+ for (i = 0; i < opal_fdm->region_cnt; i++) {
+ rc = opal_mpipl_update(OPAL_MPIPL_ADD_RANGE,
+ opal_fdm->rgn[i].src,
+ opal_fdm->rgn[i].dest,
+ opal_fdm->rgn[i].size);
+ if (rc != OPAL_SUCCESS)
+ break;
+
+ opal_fdm->registered_regions++;
+ }
+
+ switch (rc) {
+ case OPAL_SUCCESS:
+ pr_info("Registration is successful!\n");
+ fadump_conf->dump_registered = 1;
+ err = 0;
+ break;
+ case OPAL_RESOURCE:
+ /* If MAX regions limit in f/w is hit, warn and proceed. */
+ pr_warn("%d regions could not be registered for MPIPL as MAX limit is reached!\n",
+ (opal_fdm->region_cnt - opal_fdm->registered_regions));
+ fadump_conf->dump_registered = 1;
+ err = 0;
+ break;
+ case OPAL_PARAMETER:
+ pr_err("Failed to register. Parameter Error(%lld).\n", rc);
+ break;
+ case OPAL_HARDWARE:
+ pr_err("Support not available.\n");
+ fadump_conf->fadump_supported = 0;
+ fadump_conf->fadump_enabled = 0;
+ break;
+ default:
+ pr_err("Failed to register. Unknown Error(%lld).\n", rc);
+ break;
+ }
+
+ /*
+ * If some regions were registered before OPAL_MPIPL_ADD_RANGE
+ * OPAL call failed, unregister all regions.
+ */
+ if ((err < 0) && (opal_fdm->registered_regions > 0))
+ opal_fadump_unregister(fadump_conf);
+
+ return err;
+}
+
+static int opal_fadump_unregister(struct fw_dump *fadump_conf)
+{
+ s64 rc;
+
+ rc = opal_mpipl_update(OPAL_MPIPL_REMOVE_ALL, 0, 0, 0);
+ if (rc) {
+ pr_err("Failed to un-register - unexpected Error(%lld).\n", rc);
+ return -EIO;
+ }
+
+ opal_fdm->registered_regions = 0;
+ fadump_conf->dump_registered = 0;
+ return 0;
+}
+
+static int opal_fadump_invalidate(struct fw_dump *fadump_conf)
+{
+ s64 rc;
+
+ rc = opal_mpipl_update(OPAL_MPIPL_FREE_PRESERVED_MEMORY, 0, 0, 0);
+ if (rc) {
+ pr_err("Failed to invalidate - unexpected Error(%lld).\n", rc);
+ return -EIO;
+ }
+
+ fadump_conf->dump_active = 0;
+ opal_fdm_active = NULL;
+ return 0;
+}
+
+static void opal_fadump_cleanup(struct fw_dump *fadump_conf)
+{
+ s64 ret;
+
+ ret = opal_mpipl_register_tag(OPAL_MPIPL_TAG_KERNEL, 0);
+ if (ret != OPAL_SUCCESS)
+ pr_warn("Could not reset (%llu) kernel metadata tag!\n", ret);
+}
+
+/*
+ * Verify if CPU state data is available. If available, do a bit of sanity
+ * checking before processing this data.
+ */
+static bool __init is_opal_fadump_cpu_data_valid(struct fw_dump *fadump_conf)
+{
+ if (!opal_cpu_metadata)
+ return false;
+
+ fadump_conf->cpu_state_data_version =
+ be32_to_cpu(opal_cpu_metadata->cpu_data_version);
+ fadump_conf->cpu_state_entry_size =
+ be32_to_cpu(opal_cpu_metadata->cpu_data_size);
+ fadump_conf->cpu_state_dest_vaddr =
+ (u64)__va(be64_to_cpu(opal_cpu_metadata->region[0].dest));
+ fadump_conf->cpu_state_data_size =
+ be64_to_cpu(opal_cpu_metadata->region[0].size);
+
+ if (fadump_conf->cpu_state_data_version != HDAT_FADUMP_CPU_DATA_VER) {
+ pr_warn("Supported CPU state data version: %u, found: %d!\n",
+ HDAT_FADUMP_CPU_DATA_VER,
+ fadump_conf->cpu_state_data_version);
+ pr_warn("WARNING: F/W using newer CPU state data format!!\n");
+ }
+
+ if ((fadump_conf->cpu_state_dest_vaddr == 0) ||
+ (fadump_conf->cpu_state_entry_size == 0) ||
+ (fadump_conf->cpu_state_entry_size >
+ fadump_conf->cpu_state_data_size)) {
+ pr_err("CPU state data is invalid. Ignoring!\n");
+ return false;
+ }
+
+ return true;
+}
+
+/*
+ * Convert CPU state data saved at the time of crash into ELF notes.
+ *
+ * While the crashing CPU's register data is saved by the kernel, CPU state
+ * data for all CPUs is saved by f/w. In CPU state data provided by f/w,
+ * each register entry is of 16 bytes, a numerical identifier along with
+ * a GPR/SPR flag in the first 8 bytes and the register value in the next
+ * 8 bytes. For more details refer to F/W documentation. If this data is
+ * missing or in unsupported format, append crashing CPU's register data
+ * saved by the kernel in the PT_NOTE, to have something to work with in
+ * the vmcore file.
+ */
+static int __init
+opal_fadump_build_cpu_notes(struct fw_dump *fadump_conf,
+ struct fadump_crash_info_header *fdh)
+{
+ u32 thread_pir, size_per_thread, regs_offset, regs_cnt, reg_esize;
+ struct hdat_fadump_thread_hdr *thdr;
+ bool is_cpu_data_valid = false;
+ u32 num_cpus = 1, *note_buf;
+ struct pt_regs regs;
+ char *bufp;
+ int rc, i;
+
+ if (is_opal_fadump_cpu_data_valid(fadump_conf)) {
+ size_per_thread = fadump_conf->cpu_state_entry_size;
+ num_cpus = (fadump_conf->cpu_state_data_size / size_per_thread);
+ bufp = __va(fadump_conf->cpu_state_dest_vaddr);
+ is_cpu_data_valid = true;
+ }
+
+ rc = fadump_setup_cpu_notes_buf(num_cpus);
+ if (rc != 0)
+ return rc;
+
+ note_buf = (u32 *)fadump_conf->cpu_notes_buf_vaddr;
+ if (!is_cpu_data_valid)
+ goto out;
+
+ /*
+ * Offset for register entries, entry size and registers count is
+ * duplicated in every thread header in keeping with HDAT format.
+ * Use these values from the first thread header.
+ */
+ thdr = (struct hdat_fadump_thread_hdr *)bufp;
+ regs_offset = (offsetof(struct hdat_fadump_thread_hdr, offset) +
+ be32_to_cpu(thdr->offset));
+ reg_esize = be32_to_cpu(thdr->esize);
+ regs_cnt = be32_to_cpu(thdr->ecnt);
+
+ pr_debug("--------CPU State Data------------\n");
+ pr_debug("NumCpus : %u\n", num_cpus);
+ pr_debug("\tOffset: %u, Entry size: %u, Cnt: %u\n",
+ regs_offset, reg_esize, regs_cnt);
+
+ for (i = 0; i < num_cpus; i++, bufp += size_per_thread) {
+ thdr = (struct hdat_fadump_thread_hdr *)bufp;
+
+ thread_pir = be32_to_cpu(thdr->pir);
+ pr_debug("[%04d] PIR: 0x%x, core state: 0x%02x\n",
+ i, thread_pir, thdr->core_state);
+
+ /*
+ * If this is kernel initiated crash, crashing_cpu would be set
+ * appropriately and register data of the crashing CPU saved by
+ * crashing kernel. Add this saved register data of crashing CPU
+ * to elf notes and populate the pt_regs for the remaining CPUs
+ * from register state data provided by firmware.
+ */
+ if (fdh->crashing_cpu == thread_pir) {
+ note_buf = fadump_regs_to_elf_notes(note_buf,
+ &fdh->regs);
+ pr_debug("Crashing CPU PIR: 0x%x - R1 : 0x%lx, NIP : 0x%lx\n",
+ fdh->crashing_cpu, fdh->regs.gpr[1],
+ fdh->regs.nip);
+ continue;
+ }
+
+ /*
+ * Register state data of MAX cores is provided by firmware,
+ * but some of this cores may not be active. So, while
+ * processing register state data, check core state and
+ * skip threads that belong to inactive cores.
+ */
+ if (thdr->core_state == HDAT_FADUMP_CORE_INACTIVE)
+ continue;
+
+ opal_fadump_read_regs((bufp + regs_offset), regs_cnt,
+ reg_esize, true, &regs);
+ note_buf = fadump_regs_to_elf_notes(note_buf, &regs);
+ pr_debug("CPU PIR: 0x%x - R1 : 0x%lx, NIP : 0x%lx\n",
+ thread_pir, regs.gpr[1], regs.nip);
+ }
+
+out:
+ /*
+ * CPU state data is invalid/unsupported. Try appending crashing CPU's
+ * register data, if it is saved by the kernel.
+ */
+ if (fadump_conf->cpu_notes_buf_vaddr == (u64)note_buf) {
+ if (fdh->crashing_cpu == FADUMP_CPU_UNKNOWN) {
+ fadump_free_cpu_notes_buf();
+ return -ENODEV;
+ }
+
+ pr_warn("WARNING: appending only crashing CPU's register data\n");
+ note_buf = fadump_regs_to_elf_notes(note_buf, &(fdh->regs));
+ }
+
+ final_note(note_buf);
+
+ pr_debug("Updating elfcore header (%llx) with cpu notes\n",
+ fdh->elfcorehdr_addr);
+ fadump_update_elfcore_header(__va(fdh->elfcorehdr_addr));
+ return 0;
+}
+
+static int __init opal_fadump_process(struct fw_dump *fadump_conf)
+{
+ struct fadump_crash_info_header *fdh;
+ int rc = -EINVAL;
+
+ if (!opal_fdm_active || !fadump_conf->fadumphdr_addr)
+ return rc;
+
+ /* Validate the fadump crash info header */
+ fdh = __va(fadump_conf->fadumphdr_addr);
+ if (fdh->magic_number != FADUMP_CRASH_INFO_MAGIC) {
+ pr_err("Crash info header is not valid.\n");
+ return rc;
+ }
+
+#ifdef CONFIG_OPAL_CORE
+ /*
+ * If this is a kernel initiated crash, crashing_cpu would be set
+ * appropriately and register data of the crashing CPU saved by
+ * crashing kernel. Add this saved register data of crashing CPU
+ * to elf notes and populate the pt_regs for the remaining CPUs
+ * from register state data provided by firmware.
+ */
+ if (fdh->crashing_cpu != FADUMP_CPU_UNKNOWN)
+ kernel_initiated = true;
+#endif
+
+ rc = opal_fadump_build_cpu_notes(fadump_conf, fdh);
+ if (rc)
+ return rc;
+
+ /*
+ * We are done validating dump info and elfcore header is now ready
+ * to be exported. set elfcorehdr_addr so that vmcore module will
+ * export the elfcore header through '/proc/vmcore'.
+ */
+ elfcorehdr_addr = fdh->elfcorehdr_addr;
+
+ return rc;
+}
+
+static void opal_fadump_region_show(struct fw_dump *fadump_conf,
+ struct seq_file *m)
+{
+ const struct opal_fadump_mem_struct *fdm_ptr;
+ u64 dumped_bytes = 0;
+ int i;
+
+ if (fadump_conf->dump_active)
+ fdm_ptr = opal_fdm_active;
+ else
+ fdm_ptr = opal_fdm;
+
+ for (i = 0; i < fdm_ptr->region_cnt; i++) {
+ /*
+ * Only regions that are registered for MPIPL
+ * would have dump data.
+ */
+ if ((fadump_conf->dump_active) &&
+ (i < fdm_ptr->registered_regions))
+ dumped_bytes = fdm_ptr->rgn[i].size;
+
+ seq_printf(m, "DUMP: Src: %#016llx, Dest: %#016llx, ",
+ fdm_ptr->rgn[i].src, fdm_ptr->rgn[i].dest);
+ seq_printf(m, "Size: %#llx, Dumped: %#llx bytes\n",
+ fdm_ptr->rgn[i].size, dumped_bytes);
+ }
+
+ /* Dump is active. Show reserved area start address. */
+ if (fadump_conf->dump_active) {
+ seq_printf(m, "\nMemory above %#016lx is reserved for saving crash dump\n",
+ fadump_conf->reserve_dump_area_start);
+ }
+}
+
+static void opal_fadump_trigger(struct fadump_crash_info_header *fdh,
+ const char *msg)
+{
+ int rc;
+
+ /*
+ * Unlike on pSeries platform, logical CPU number is not provided
+ * with architected register state data. So, store the crashing
+ * CPU's PIR instead to plug the appropriate register data for
+ * crashing CPU in the vmcore file.
+ */
+ fdh->crashing_cpu = (u32)mfspr(SPRN_PIR);
+
+ rc = opal_cec_reboot2(OPAL_REBOOT_MPIPL, msg);
+ if (rc == OPAL_UNSUPPORTED) {
+ pr_emerg("Reboot type %d not supported.\n",
+ OPAL_REBOOT_MPIPL);
+ } else if (rc == OPAL_HARDWARE)
+ pr_emerg("No backend support for MPIPL!\n");
+}
+
+static struct fadump_ops opal_fadump_ops = {
+ .fadump_init_mem_struct = opal_fadump_init_mem_struct,
+ .fadump_get_metadata_size = opal_fadump_get_metadata_size,
+ .fadump_setup_metadata = opal_fadump_setup_metadata,
+ .fadump_get_bootmem_min = opal_fadump_get_bootmem_min,
+ .fadump_register = opal_fadump_register,
+ .fadump_unregister = opal_fadump_unregister,
+ .fadump_invalidate = opal_fadump_invalidate,
+ .fadump_cleanup = opal_fadump_cleanup,
+ .fadump_process = opal_fadump_process,
+ .fadump_region_show = opal_fadump_region_show,
+ .fadump_trigger = opal_fadump_trigger,
+};
+
+void __init opal_fadump_dt_scan(struct fw_dump *fadump_conf, u64 node)
+{
+ const __be32 *prop;
+ unsigned long dn;
+ u64 addr = 0;
+ int i, len;
+ s64 ret;
+
+ /*
+ * Check if Firmware-Assisted Dump is supported. if yes, check
+ * if dump has been initiated on last reboot.
+ */
+ dn = of_get_flat_dt_subnode_by_name(node, "dump");
+ if (dn == -FDT_ERR_NOTFOUND) {
+ pr_debug("FADump support is missing!\n");
+ return;
+ }
+
+ if (!of_flat_dt_is_compatible(dn, "ibm,opal-dump")) {
+ pr_err("Support missing for this f/w version!\n");
+ return;
+ }
+
+ prop = of_get_flat_dt_prop(dn, "fw-load-area", &len);
+ if (prop) {
+ /*
+ * Each f/w load area is an (address,size) pair,
+ * 2 cells each, totalling 4 cells per range.
+ */
+ for (i = 0; i < len / (sizeof(*prop) * 4); i++) {
+ u64 base, end;
+
+ base = of_read_number(prop + (i * 4) + 0, 2);
+ end = base;
+ end += of_read_number(prop + (i * 4) + 2, 2);
+ if (end > OPAL_FADUMP_MIN_BOOT_MEM) {
+ pr_err("F/W load area: 0x%llx-0x%llx\n",
+ base, end);
+ pr_err("F/W version not supported!\n");
+ return;
+ }
+ }
+ }
+
+ fadump_conf->ops = &opal_fadump_ops;
+ fadump_conf->fadump_supported = 1;
+
+ /*
+ * Firmware supports 32-bit field for size. Align it to PAGE_SIZE
+ * and request firmware to copy multiple kernel boot memory regions.
+ */
+ fadump_conf->max_copy_size = _ALIGN_DOWN(U32_MAX, PAGE_SIZE);
+
+ /*
+ * Check if dump has been initiated on last reboot.
+ */
+ prop = of_get_flat_dt_prop(dn, "mpipl-boot", NULL);
+ if (!prop)
+ return;
+
+ ret = opal_mpipl_query_tag(OPAL_MPIPL_TAG_KERNEL, &addr);
+ if ((ret != OPAL_SUCCESS) || !addr) {
+ pr_err("Failed to get Kernel metadata (%lld)\n", ret);
+ return;
+ }
+
+ addr = be64_to_cpu(addr);
+ pr_debug("Kernel metadata addr: %llx\n", addr);
+
+ opal_fdm_active = __va(addr);
+ if (opal_fdm_active->version != OPAL_FADUMP_VERSION) {
+ pr_warn("Supported kernel metadata version: %u, found: %d!\n",
+ OPAL_FADUMP_VERSION, opal_fdm_active->version);
+ pr_warn("WARNING: Kernel metadata format mismatch identified! Core file maybe corrupted..\n");
+ }
+
+ /* Kernel regions not registered with f/w for MPIPL */
+ if (opal_fdm_active->registered_regions == 0) {
+ opal_fdm_active = NULL;
+ return;
+ }
+
+ ret = opal_mpipl_query_tag(OPAL_MPIPL_TAG_CPU, &addr);
+ if (addr) {
+ addr = be64_to_cpu(addr);
+ pr_debug("CPU metadata addr: %llx\n", addr);
+ opal_cpu_metadata = __va(addr);
+ }
+
+ pr_info("Firmware-assisted dump is active.\n");
+ fadump_conf->dump_active = 1;
+ opal_fadump_get_config(fadump_conf, opal_fdm_active);
+}
+#endif /* !CONFIG_PRESERVE_FA_DUMP */