From 2a1b06dd3a17ac278494da3c15cac84684346d22 Mon Sep 17 00:00:00 2001 From: Hari Bathini Date: Wed, 11 Sep 2019 20:21:59 +0530 Subject: [PATCH] powerpc/fadump: process the crashdump by exporting it as /proc/vmcore Add support in the kernel to process the crash'ed kernel's memory preserved during MPIPL and export it as /proc/vmcore file for the userland scripts to filter and analyze it later. Signed-off-by: Hari Bathini Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/156821351482.5656.6255805804744333073.stgit@hbathini.in.ibm.com --- arch/powerpc/platforms/powernv/opal-fadump.c | 147 ++++++++++++++++++++++++++- 1 file changed, 145 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/platforms/powernv/opal-fadump.c b/arch/powerpc/platforms/powernv/opal-fadump.c index a4b96a7..5ace7c4 100644 --- a/arch/powerpc/platforms/powernv/opal-fadump.c +++ b/arch/powerpc/platforms/powernv/opal-fadump.c @@ -12,6 +12,7 @@ #include #include #include +#include #include #include @@ -19,6 +20,7 @@ #include "opal-fadump.h" +static const struct opal_fadump_mem_struct *opal_fdm_active; static struct opal_fadump_mem_struct *opal_fdm; static int opal_fadump_unregister(struct fw_dump *fadump_conf); @@ -39,6 +41,37 @@ static void opal_fadump_update_config(struct fw_dump *fadump_conf, 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) +{ + int i; + + if (!fadump_conf->dump_active) + return; + + fadump_conf->boot_memory_size = 0; + + pr_debug("Boot memory regions:\n"); + for (i = 0; i < fdm->region_cnt; i++) { + pr_debug("\t%d. base: 0x%llx, size: 0x%llx\n", + (i + 1), fdm->rgn[i].src, fdm->rgn[i].size); + + fadump_conf->boot_memory_size += fdm->rgn[i].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; + + opal_fadump_update_config(fadump_conf, fdm); +} + /* Initialize kernel metadata */ static void opal_fadump_init_metadata(struct opal_fadump_mem_struct *fdm) { @@ -209,24 +242,97 @@ static void opal_fadump_cleanup(struct fw_dump *fadump_conf) pr_warn("Could not reset (%llu) kernel metadata tag!\n", ret); } +/* + * Convert CPU state data saved at the time of crash into ELF notes. + * + * Append crashing CPU's register data saved by the kernel in the PT_NOTE. + */ +static int __init +opal_fadump_build_cpu_notes(struct fw_dump *fadump_conf, + struct fadump_crash_info_header *fdh) +{ + u32 num_cpus = 1, *note_buf; + int rc; + + if (fdh->crashing_cpu == FADUMP_CPU_UNKNOWN) + return -ENODEV; + + /* Allocate CPU notes buffer to hold crashing cpu notes. */ + rc = fadump_setup_cpu_notes_buf(num_cpus); + if (rc != 0) + return rc; + + note_buf = (u32 *)fadump_conf->cpu_notes_buf_vaddr; + 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) { - return -EINVAL; + 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; + } + + 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 = opal_fdm; + 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, @@ -257,7 +363,11 @@ static struct fadump_ops opal_fadump_ops = { void __init opal_fadump_dt_scan(struct fw_dump *fadump_conf, u64 node) { + const __be32 *prop; unsigned long dn; + u64 addr = 0; + s64 ret; + /* * Check if Firmware-Assisted Dump is supported. if yes, check @@ -276,4 +386,37 @@ void __init opal_fadump_dt_scan(struct fw_dump *fadump_conf, u64 node) fadump_conf->ops = &opal_fadump_ops; fadump_conf->fadump_supported = 1; + + /* + * 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; + } + + pr_info("Firmware-assisted dump is active.\n"); + fadump_conf->dump_active = 1; + opal_fadump_get_config(fadump_conf, opal_fdm_active); } -- 2.7.4