[PATCH v5 16/31] powernv/fadump: process the crashdump by exporting it as /proc/vmcore
Hari Bathini
hbathini at linux.ibm.com
Tue Aug 20 22:06:05 AEST 2019
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 <hbathini at linux.ibm.com>
---
arch/powerpc/platforms/powernv/opal-fadump.c | 165 ++++++++++++++++++++++++++
1 file changed, 163 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/platforms/powernv/opal-fadump.c b/arch/powerpc/platforms/powernv/opal-fadump.c
index a755705..10f6086 100644
--- a/arch/powerpc/platforms/powernv/opal-fadump.c
+++ b/arch/powerpc/platforms/powernv/opal-fadump.c
@@ -14,6 +14,7 @@
#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>
@@ -21,6 +22,7 @@
#include "../../kernel/fadump-common.h"
#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);
@@ -41,6 +43,37 @@ 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)
{
@@ -215,24 +248,114 @@ 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.
+ */
+static int __init opal_fadump_build_cpu_notes(struct fw_dump *fadump_conf)
+{
+ u32 num_cpus, *note_buf;
+ struct fadump_crash_info_header *fdh = NULL;
+
+ num_cpus = 1;
+ /* Allocate buffer to hold cpu crash notes. */
+ fadump_conf->cpu_notes_buf_size = num_cpus * sizeof(note_buf_t);
+ fadump_conf->cpu_notes_buf_size =
+ PAGE_ALIGN(fadump_conf->cpu_notes_buf_size);
+ note_buf = fadump_cpu_notes_buf_alloc(fadump_conf->cpu_notes_buf_size);
+ if (!note_buf) {
+ pr_err("Failed to allocate 0x%lx bytes for cpu notes buffer\n",
+ fadump_conf->cpu_notes_buf_size);
+ return -ENOMEM;
+ }
+ fadump_conf->cpu_notes_buf = __pa(note_buf);
+
+ pr_debug("Allocated buffer for cpu notes of size %ld at %p\n",
+ (num_cpus * sizeof(note_buf_t)), note_buf);
+
+ if (fadump_conf->fadumphdr_addr)
+ fdh = __va(fadump_conf->fadumphdr_addr);
+
+ if (fdh && (fdh->crashing_cpu != FADUMP_CPU_UNKNOWN)) {
+ 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(fadump_conf,
+ __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 = 0;
+
+ if (!opal_fdm_active || !fadump_conf->fadumphdr_addr)
+ return -EINVAL;
+
+ /* 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 -EINVAL;
+ }
+
+ /*
+ * TODO: To build cpu notes, find a way to map PIR to logical id.
+ * Also, we may need different method for pseries and powernv.
+ * The currently booted kernel could have a different PIR to
+ * logical id mapping. So, try saving info of previous kernel's
+ * paca to get the right PIR to logical id mapping.
+ */
+ rc = opal_fadump_build_cpu_notes(fadump_conf);
+ 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)
{
int i;
- const struct opal_fadump_mem_struct *fdm_ptr = opal_fdm;
+ const struct opal_fadump_mem_struct *fdm_ptr;
u64 dumped_bytes = 0;
+ 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,
@@ -264,6 +387,7 @@ static struct fadump_ops opal_fadump_ops = {
int __init opal_fadump_dt_scan(struct fw_dump *fadump_conf, ulong node)
{
unsigned long dn;
+ const __be32 *prop;
/*
* Check if Firmware-Assisted Dump is supported. if yes, check
@@ -283,5 +407,42 @@ int __init opal_fadump_dt_scan(struct fw_dump *fadump_conf, ulong 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) {
+ u64 addr = 0;
+ s64 ret;
+ const struct opal_fadump_mem_struct *r_opal_fdm_active;
+
+ 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 1;
+ }
+
+ addr = be64_to_cpu(addr);
+ pr_debug("Kernel metadata addr: %llx\n", addr);
+
+ opal_fdm_active = __va(addr);
+ r_opal_fdm_active = (void *)addr;
+ if (r_opal_fdm_active->version != OPAL_FADUMP_VERSION) {
+ pr_err("FADump active but version (%u) unsupported!\n",
+ r_opal_fdm_active->version);
+ return 1;
+ }
+
+ /* Kernel regions not registered with f/w for MPIPL */
+ if (r_opal_fdm_active->registered_regions == 0) {
+ opal_fdm_active = NULL;
+ return 1;
+ }
+
+ pr_info("Firmware-assisted dump is active.\n");
+ fadump_conf->dump_active = 1;
+ opal_fadump_get_config(fadump_conf, r_opal_fdm_active);
+ }
+
return 1;
}
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