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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 (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 */