linux/arch/powerpc/platforms/powernv/opal-fadump.c

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// 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 (be16_to_cpu(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", be16_to_cpu(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 = be64_to_cpu(fdm->rgn[0].dest);
pr_debug("Destination address of boot memory regions: %#016llx\n",
fadump_conf->boot_mem_dest_addr);
fadump_conf->fadumphdr_addr = be64_to_cpu(fdm->fadumphdr_addr);
}
/*
* This function is called in the capture kernel to get configuration details
* from metadata setup by the first kernel.
*/
static void __init 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 < be16_to_cpu(fdm->region_cnt); i++) {
base = be64_to_cpu(fdm->rgn[i].src);
size = be64_to_cpu(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 = be64_to_cpu(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 (be16_to_cpu(fdm->region_cnt) > be16_to_cpu(fdm->registered_regions)) {
pr_warn("Not all memory regions were saved!!!\n");
pr_warn(" Unsaved memory regions:\n");
i = be16_to_cpu(fdm->registered_regions);
while (i < be16_to_cpu(fdm->region_cnt)) {
pr_warn("\t[%03d] base: 0x%llx, size: 0x%llx\n",
i, be64_to_cpu(fdm->rgn[i].src),
be64_to_cpu(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 = be16_to_cpu(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 = cpu_to_be16(0);
fdm->registered_regions = cpu_to_be16(0);
fdm->fadumphdr_addr = cpu_to_be64(0);
}
static u64 opal_fadump_init_mem_struct(struct fw_dump *fadump_conf)
{
u64 addr = fadump_conf->reserve_dump_area_start;
u16 reg_cnt;
int i;
opal_fdm = __va(fadump_conf->kernel_metadata);
opal_fadump_init_metadata(opal_fdm);
/* Boot memory regions */
reg_cnt = be16_to_cpu(opal_fdm->region_cnt);
for (i = 0; i < fadump_conf->boot_mem_regs_cnt; i++) {
opal_fdm->rgn[i].src = cpu_to_be64(fadump_conf->boot_mem_addr[i]);
opal_fdm->rgn[i].dest = cpu_to_be64(addr);
opal_fdm->rgn[i].size = cpu_to_be64(fadump_conf->boot_mem_sz[i]);
reg_cnt++;
addr += fadump_conf->boot_mem_sz[i];
}
opal_fdm->region_cnt = cpu_to_be16(reg_cnt);
/*
* Kernel metadata is passed to f/w and retrieved in capture kernel.
* So, use it to save fadump header address instead of calculating it.
*/
opal_fdm->fadumphdr_addr = cpu_to_be64(be64_to_cpu(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;
u16 registered_regs;
int i, err = -EIO;
registered_regs = be16_to_cpu(opal_fdm->registered_regions);
for (i = 0; i < be16_to_cpu(opal_fdm->region_cnt); i++) {
rc = opal_mpipl_update(OPAL_MPIPL_ADD_RANGE,
be64_to_cpu(opal_fdm->rgn[i].src),
be64_to_cpu(opal_fdm->rgn[i].dest),
be64_to_cpu(opal_fdm->rgn[i].size));
if (rc != OPAL_SUCCESS)
break;
registered_regs++;
}
opal_fdm->registered_regions = cpu_to_be16(registered_regs);
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",
(be16_to_cpu(opal_fdm->region_cnt) -
be16_to_cpu(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) && (be16_to_cpu(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 = cpu_to_be16(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",
powerpc: make fadump resilient with memory add/remove events Due to changes in memory resources caused by either memory hotplug or online/offline events, the elfcorehdr, which describes the CPUs and memory of the crashed kernel to the kernel that collects the dump (known as second/fadump kernel), becomes outdated. Consequently, attempting dump collection with an outdated elfcorehdr can lead to failed or inaccurate dump collection. Memory hotplug or online/offline events is referred as memory add/remove events in reset of the commit message. The current solution to address the aforementioned issue is as follows: Monitor memory add/remove events in userspace using udev rules, and re-register fadump whenever there are changes in memory resources. This leads to the creation of a new elfcorehdr with updated system memory information. There are several notable issues associated with re-registering fadump for every memory add/remove events. 1. Bulk memory add/remove events with udev-based fadump re-registration can lead to race conditions and, more importantly, it creates a wide window during which fadump is inactive until all memory add/remove events are settled. 2. Re-registering fadump for every memory add/remove event is inefficient. 3. The memory for elfcorehdr is allocated based on the memblock regions available during early boot and remains fixed thereafter. However, if elfcorehdr is later recreated with additional memblock regions, its size will increase, potentially leading to memory corruption. Address the aforementioned challenges by shifting the creation of elfcorehdr from the first kernel (also referred as the crashed kernel), where it was created and frequently recreated for every memory add/remove event, to the fadump kernel. As a result, the elfcorehdr only needs to be created once, thus eliminating the necessity to re-register fadump during memory add/remove events. At present, the first kernel prepares fadump header and stores it in the fadump reserved area. The fadump header includes the start address of the elfcorehdr, crashing CPU details, and other relevant information. In the event of a crash in the first kernel, the second/fadump boots and accesses the fadump header prepared by the first kernel. It then performs the following steps in a platform-specific function [rtas|opal]_fadump_process: 1. Sanity check for fadump header 2. Update CPU notes in elfcorehdr Along with the above, update the setup_fadump()/fadump.c to create elfcorehdr and set its address to the global variable elfcorehdr_addr for the vmcore module to process it in the second/fadump kernel. Section below outlines the information required to create the elfcorehdr and the changes made to make it available to the fadump kernel if it's not already. To create elfcorehdr, the following crashed kernel information is required: CPU notes, vmcoreinfo, and memory ranges. At present, the CPU notes are already prepared in the fadump kernel, so no changes are needed in that regard. The fadump kernel has access to all crashed kernel memory regions, including boot memory regions that are relocated by firmware to fadump reserved areas, so no changes for that either. However, it is necessary to add new members to the fadump header, i.e., the 'fadump_crash_info_header' structure, in order to pass the crashed kernel's vmcoreinfo address and its size to fadump kernel. In addition to the vmcoreinfo address and size, there are a few other attributes also added to the fadump_crash_info_header structure. 1. version: It stores the fadump header version, which is currently set to 1. This provides flexibility to update the fadump crash info header in the future without changing the magic number. For each change in the fadump header, the version will be increased. This will help the updated kernel determine how to handle kernel dumps from older kernels. The magic number remains relevant for checking fadump header corruption. 2. pt_regs_sz/cpu_mask_sz: Store size of pt_regs and cpu_mask structure of first kernel. These attributes are used to prevent dump processing if the sizes of pt_regs or cpu_mask structure differ between the first and fadump kernels. Note: if either first/crashed kernel or second/fadump kernel do not have the changes introduced here then kernel fail to collect the dump and prints relevant error message on the console. Signed-off-by: Sourabh Jain <sourabhjain@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://msgid.link/20240422195932.1583833-2-sourabhjain@linux.ibm.com
2024-04-23 01:29:30 +05:30
fadump_conf->elfcorehdr_addr);
fadump_update_elfcore_header((char *)fadump_conf->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;
fdh = __va(fadump_conf->fadumphdr_addr);
#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
powerpc: make fadump resilient with memory add/remove events Due to changes in memory resources caused by either memory hotplug or online/offline events, the elfcorehdr, which describes the CPUs and memory of the crashed kernel to the kernel that collects the dump (known as second/fadump kernel), becomes outdated. Consequently, attempting dump collection with an outdated elfcorehdr can lead to failed or inaccurate dump collection. Memory hotplug or online/offline events is referred as memory add/remove events in reset of the commit message. The current solution to address the aforementioned issue is as follows: Monitor memory add/remove events in userspace using udev rules, and re-register fadump whenever there are changes in memory resources. This leads to the creation of a new elfcorehdr with updated system memory information. There are several notable issues associated with re-registering fadump for every memory add/remove events. 1. Bulk memory add/remove events with udev-based fadump re-registration can lead to race conditions and, more importantly, it creates a wide window during which fadump is inactive until all memory add/remove events are settled. 2. Re-registering fadump for every memory add/remove event is inefficient. 3. The memory for elfcorehdr is allocated based on the memblock regions available during early boot and remains fixed thereafter. However, if elfcorehdr is later recreated with additional memblock regions, its size will increase, potentially leading to memory corruption. Address the aforementioned challenges by shifting the creation of elfcorehdr from the first kernel (also referred as the crashed kernel), where it was created and frequently recreated for every memory add/remove event, to the fadump kernel. As a result, the elfcorehdr only needs to be created once, thus eliminating the necessity to re-register fadump during memory add/remove events. At present, the first kernel prepares fadump header and stores it in the fadump reserved area. The fadump header includes the start address of the elfcorehdr, crashing CPU details, and other relevant information. In the event of a crash in the first kernel, the second/fadump boots and accesses the fadump header prepared by the first kernel. It then performs the following steps in a platform-specific function [rtas|opal]_fadump_process: 1. Sanity check for fadump header 2. Update CPU notes in elfcorehdr Along with the above, update the setup_fadump()/fadump.c to create elfcorehdr and set its address to the global variable elfcorehdr_addr for the vmcore module to process it in the second/fadump kernel. Section below outlines the information required to create the elfcorehdr and the changes made to make it available to the fadump kernel if it's not already. To create elfcorehdr, the following crashed kernel information is required: CPU notes, vmcoreinfo, and memory ranges. At present, the CPU notes are already prepared in the fadump kernel, so no changes are needed in that regard. The fadump kernel has access to all crashed kernel memory regions, including boot memory regions that are relocated by firmware to fadump reserved areas, so no changes for that either. However, it is necessary to add new members to the fadump header, i.e., the 'fadump_crash_info_header' structure, in order to pass the crashed kernel's vmcoreinfo address and its size to fadump kernel. In addition to the vmcoreinfo address and size, there are a few other attributes also added to the fadump_crash_info_header structure. 1. version: It stores the fadump header version, which is currently set to 1. This provides flexibility to update the fadump crash info header in the future without changing the magic number. For each change in the fadump header, the version will be increased. This will help the updated kernel determine how to handle kernel dumps from older kernels. The magic number remains relevant for checking fadump header corruption. 2. pt_regs_sz/cpu_mask_sz: Store size of pt_regs and cpu_mask structure of first kernel. These attributes are used to prevent dump processing if the sizes of pt_regs or cpu_mask structure differ between the first and fadump kernels. Note: if either first/crashed kernel or second/fadump kernel do not have the changes introduced here then kernel fail to collect the dump and prints relevant error message on the console. Signed-off-by: Sourabh Jain <sourabhjain@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://msgid.link/20240422195932.1583833-2-sourabhjain@linux.ibm.com
2024-04-23 01:29:30 +05:30
return opal_fadump_build_cpu_notes(fadump_conf, fdh);
}
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 < be16_to_cpu(fdm_ptr->region_cnt); i++) {
/*
* Only regions that are registered for MPIPL
* would have dump data.
*/
if ((fadump_conf->dump_active) &&
(i < be16_to_cpu(fdm_ptr->registered_regions)))
dumped_bytes = be64_to_cpu(fdm_ptr->rgn[i].size);
seq_printf(m, "DUMP: Src: %#016llx, Dest: %#016llx, ",
be64_to_cpu(fdm_ptr->rgn[i].src),
be64_to_cpu(fdm_ptr->rgn[i].dest));
seq_printf(m, "Size: %#llx, Dumped: %#llx bytes\n",
be64_to_cpu(fdm_ptr->rgn[i].size), dumped_bytes);
}
/* Dump is active. Show preserved area start address. */
if (fadump_conf->dump_active) {
seq_printf(m, "\nMemory above %#016llx is reserved for saving crash dump\n",
fadump_conf->boot_mem_top);
}
}
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");
}
/* FADUMP_MAX_MEM_REGS or lower */
static int opal_fadump_max_boot_mem_rgns(void)
{
return FADUMP_MAX_MEM_REGS;
}
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,
.fadump_max_boot_mem_rgns = opal_fadump_max_boot_mem_rgns,
};
void __init opal_fadump_dt_scan(struct fw_dump *fadump_conf, u64 node)
{
const __be32 *prop;
unsigned long dn;
__be64 be_addr;
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;
/* TODO: Add support to pass additional parameters */
fadump_conf->param_area_supported = 0;
/*
* 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, &be_addr);
if ((ret != OPAL_SUCCESS) || !be_addr) {
pr_err("Failed to get Kernel metadata (%lld)\n", ret);
return;
}
addr = be64_to_cpu(be_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 (be16_to_cpu(opal_fdm_active->registered_regions) == 0) {
opal_fdm_active = NULL;
return;
}
ret = opal_mpipl_query_tag(OPAL_MPIPL_TAG_CPU, &be_addr);
if (be_addr) {
addr = be64_to_cpu(be_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 */