[PATCH v6 20/36] powernv/fadump: process the crashdump by exporting it as /proc/vmcore
Hari Bathini
hbathini at linux.ibm.com
Thu Sep 12 00:51:59 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>
---
Changes in v6:
* Drop the TODO that is anyway removed later in this patch series.
* Make mpipl-boot node processing code unindented.
* Avoid using r_ variables as platform takes care of them in real mode anyway.
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 <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>
@@ -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);
}
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