// SPDX-License-Identifier: GPL-2.0-only
/*
* Interface for exporting the OPAL ELF core.
* Heavily inspired from fs/proc/vmcore.c
*
* Copyright 2019, Hari Bathini, IBM Corporation.
*/
#define pr_fmt(fmt) "opal core: " fmt
#include <linux/memblock.h>
#include <linux/uaccess.h>
#include <linux/proc_fs.h>
#include <linux/elf.h>
#include <linux/elfcore.h>
#include <linux/kobject.h>
#include <linux/sysfs.h>
#include <linux/slab.h>
#include <linux/crash_core.h>
#include <linux/of.h>
#include <asm/page.h>
#include <asm/opal.h>
#include <asm/fadump-internal.h>
#include "opal-fadump.h"
#define MAX_PT_LOAD_CNT 8
/* NT_AUXV note related info */
#define AUXV_CNT 1
#define AUXV_DESC_SZ (((2 * AUXV_CNT) + 1) * sizeof(Elf64_Off))
struct opalcore_config {
u32 num_cpus;
/* PIR value of crashing CPU */
u32 crashing_cpu;
/* CPU state data info from F/W */
u64 cpu_state_destination_vaddr;
u64 cpu_state_data_size;
u64 cpu_state_entry_size;
/* OPAL memory to be exported as PT_LOAD segments */
u64 ptload_addr[MAX_PT_LOAD_CNT];
u64 ptload_size[MAX_PT_LOAD_CNT];
u64 ptload_cnt;
/* Pointer to the first PT_LOAD in the ELF core file */
Elf64_Phdr *ptload_phdr;
/* Total size of opalcore file. */
size_t opalcore_size;
/* Buffer for all the ELF core headers and the PT_NOTE */
size_t opalcorebuf_sz;
char *opalcorebuf;
/* NT_AUXV buffer */
char auxv_buf[AUXV_DESC_SZ];
};
struct opalcore {
struct list_head list;
u64 paddr;
size_t size;
loff_t offset;
};
static LIST_HEAD(opalcore_list);
static struct opalcore_config *oc_conf;
static const struct opal_mpipl_fadump *opalc_metadata;
static const struct opal_mpipl_fadump *opalc_cpu_metadata;
static struct kobject *mpipl_kobj;
/*
* Set crashing CPU's signal to SIGUSR1. if the kernel is triggered
* by kernel, SIGTERM otherwise.
*/
bool kernel_initiated;
static struct opalcore * __init get_new_element(void)
{
return kzalloc(sizeof(struct opalcore), GFP_KERNEL);
}
static inline int is_opalcore_usable(void)
{
return (oc_conf && oc_conf->opalcorebuf != NULL) ? 1 : 0;
}
static Elf64_Word *__init append_elf64_note(Elf64_Word *buf, char *name,
u32 type, void *data,
size_t data_len)
{
Elf64_Nhdr *note = (Elf64_Nhdr *)buf;
Elf64_Word namesz = strlen(name) + 1;
note->n_namesz = cpu_to_be32(namesz);
note->n_descsz = cpu_to_be32(data_len);
note->n_type = cpu_to_be32(type);
buf += DIV_ROUND_UP(sizeof(*note), sizeof(Elf64_Word));
memcpy(buf, name, namesz);
buf += DIV_ROUND_UP(namesz, sizeof(Elf64_Word));
memcpy(buf, data, data_len);
buf += DIV_ROUND_UP(data_len, sizeof(Elf64_Word));
return buf;
}
static void __init fill_prstatus(struct elf_prstatus *prstatus, int pir,
struct pt_regs *regs)
{
memset(prstatus, 0, sizeof(struct elf_prstatus));
elf_core_copy_regs(&(prstatus->pr_reg), regs);
/*
* Overload PID with PIR value.
* As a PIR value could also be '0', add an offset of '100'
* to every PIR to avoid misinterpretations in GDB.
*/
prstatus->common.pr_pid = cpu_to_be32(100 + pir);
prstatus->common.pr_ppid = cpu_to_be32(1);
/*
* Indicate SIGUSR1 for crash initiated from kernel.
* SIGTERM otherwise.
*/
if (pir == oc_conf->crashing_cpu) {
short sig;
sig = kernel_initiated ? SIGUSR1 : SIGTERM;
prstatus->common.pr_cursig = cpu_to_be16(sig);
}
}
static Elf64_Word *__init auxv_to_elf64_notes(Elf64_Word *buf,
u64 opal_boot_entry)
{
Elf64_Off *bufp = (Elf64_Off *)oc_conf->auxv_buf;
int idx = 0;
memset(bufp, 0, AUXV_DESC_SZ);
/* Entry point of OPAL */
bufp[idx++] = cpu_to_be64(AT_ENTRY);
bufp[idx++] = cpu_to_be64(opal_boot_entry);
/* end of vector */
bufp[idx++] = cpu_to_be64(AT_NULL);
buf = append_elf64_note(buf, CRASH_CORE_NOTE_NAME, NT_AUXV,
oc_conf->auxv_buf, AUXV_DESC_SZ);
return buf;
}
/*
* Read from the ELF header and then the crash dump.
* Returns number of bytes read on success, -errno on failure.
*/
static ssize_t read_opalcore(struct file *file, struct kobject *kobj,
struct bin_attribute *bin_attr, char *to,
loff_t pos, size_t count)
{
struct opalcore *m;
ssize_t tsz, avail;
loff_t tpos = pos;
if (pos >= oc_conf->opalcore_size)
return 0;
/* Adjust count if it goes beyond opalcore size */
avail = oc_conf->opalcore_size - pos;
if (count > avail)
count = avail;
if (count == 0)
return 0;
/* Read ELF core header and/or PT_NOTE segment */
if (tpos < oc_conf->opalcorebuf_sz) {
tsz = min_t(size_t, oc_conf->opalcorebuf_sz - tpos, count);
memcpy(to, oc_conf->opalcorebuf + tpos, tsz);
to += tsz;
tpos += tsz;
count -= tsz;
}
list_for_each_entry(m, &opalcore_list, list) {
/* nothing more to read here */
if (count == 0)
break;
if (tpos < m->offset + m->size) {
void *addr;
tsz = min_t(size_t, m->offset + m->size - tpos, count);
addr = (void *)(m->paddr + tpos - m->offset);
memcpy(to, __va(addr), tsz);
to += tsz;
tpos += tsz;
count -= tsz;
}
}
return (tpos - pos);
}
static struct bin_attribute opal_core_attr = {
.attr = {.name = "core", .mode = 0400},
.read = read_opalcore
};
/*
* Read CPU state dump data and convert it into ELF notes.
*
* 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.
*/
static Elf64_Word * __init opalcore_append_cpu_notes(Elf64_Word *buf)
{
u32 thread_pir, size_per_thread, regs_offset, regs_cnt, reg_esize;
struct hdat_fadump_thread_hdr *thdr;
struct elf_prstatus prstatus;
Elf64_Word *first_cpu_note;
struct pt_regs regs;
char *bufp;
int i;
size_per_thread = oc_conf->cpu_state_entry_size;
bufp = __va(oc_conf->cpu_state_destination_vaddr);
/*
* 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", oc_conf->num_cpus);
pr_debug("\tOffset: %u, Entry size: %u, Cnt: %u\n",
regs_offset, reg_esize, regs_cnt);
/*
* Skip past the first CPU note. Fill this note with the
* crashing CPU's prstatus.
*/
first_cpu_note = buf;
buf = append_elf64_note(buf, CRASH_CORE_NOTE_NAME, NT_PRSTATUS,
&prstatus, sizeof(prstatus));
for (i = 0; i < oc_conf->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);
/*
* 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, false, ®s);
pr_debug("PIR 0x%x - R1 : 0x%llx, NIP : 0x%llx\n", thread_pir,
be64_to_cpu(regs.gpr[1]), be64_to_cpu(regs.nip));
fill_prstatus(&prstatus, thread_pir, ®s);
if (thread_pir != oc_conf->crashing_cpu) {
buf = append_elf64_note(buf, CRASH_CORE_NOTE_NAME,
NT_PRSTATUS, &prstatus,
sizeof(prstatus));
} else {
/*
* Add crashing CPU as the first NT_PRSTATUS note for
* GDB to process the core file appropriately.
*/
append_elf64_note(first_cpu_note, CRASH_CORE_NOTE_NAME,
NT_PRSTATUS, &prstatus,
sizeof(prstatus));
}
}
return buf;
}
static int __init create_opalcore(void)
{
u64 opal_boot_entry, opal_base_addr, paddr;
u32 hdr_size, cpu_notes_size, count;
struct device_node *dn;
struct opalcore *new;
loff_t opalcore_off;
struct page *page;
Elf64_Phdr *phdr;
Elf64_Ehdr *elf;
int i, ret;
char *bufp;
/* Get size of header & CPU notes for OPAL core */
hdr_size = (sizeof(Elf64_Ehdr) +
((oc_conf->ptload_cnt + 1) * sizeof(Elf64_Phdr)));
cpu_notes_size = ((oc_conf->num_cpus * (CRASH_CORE_NOTE_HEAD_BYTES +
CRASH_CORE_NOTE_NAME_BYTES +
CRASH_CORE_NOTE_DESC_BYTES)) +
(CRASH_CORE_NOTE_HEAD_BYTES +
CRASH_CORE_NOTE_NAME_BYTES + AUXV_DESC_SZ));
/* Allocate buffer to setup OPAL core */
oc_conf->opalcorebuf_sz = PAGE_ALIGN(hdr_size + cpu_notes_size);
oc_conf->opalcorebuf = alloc_pages_exact(oc_conf->opalcorebuf_sz,
GFP_KERNEL | __GFP_ZERO);
if (!oc_conf->opalcorebuf) {
pr_err("Not enough memory to setup OPAL core (size: %lu)\n",
oc_conf->opalcorebuf_sz);
oc_conf->opalcorebuf_sz = 0;
return -ENOMEM;
}
count = oc_conf->opalcorebuf_sz / PAGE_SIZE;
page = virt_to_page(oc_conf->opalcorebuf);
for (i = 0; i < count; i++)
mark_page_reserved(page + i);
pr_debug("opalcorebuf = 0x%llx\n", (u64)oc_conf->opalcorebuf);
/* Read OPAL related device-tree entries */
dn = of_find_node_by_name(NULL, "ibm,opal");
if (dn) {
ret = of_property_read_u64(dn, "opal-base-address",
&opal_base_addr);
pr_debug("opal-base-address: %llx\n", opal_base_addr);
ret |= of_property_read_u64(dn, "opal-boot-address",
&opal_boot_entry);
pr_debug("opal-boot-address: %llx\n", opal_boot_entry);
}
if (!dn || ret)
pr_warn("WARNING: Failed to read OPAL base & entry values\n");
of_node_put(dn);
/* Use count to keep track of the program headers */
count = 0;
bufp = oc_conf->opalcorebuf;
elf = (Elf64_Ehdr *)bufp;
bufp += sizeof(Elf64_Ehdr);
memcpy(elf->e_ident, ELFMAG, SELFMAG);
elf->e_ident[EI_CLASS] = ELF_CLASS;
elf->e_ident[EI_DATA] = ELFDATA2MSB;
elf->e_ident[EI_VERSION] = EV_CURRENT;
elf->e_ident[EI_OSABI] = ELF_OSABI;
memset(elf->e_ident+EI_PAD, 0, EI_NIDENT-EI_PAD);
elf->e_type = cpu_to_be16(ET_CORE);
elf->e_machine = cpu_to_be16(ELF_ARCH);
elf->e_version = cpu_to_be32(EV_CURRENT);
elf->e_entry = 0;
elf->e_phoff = cpu_to_be64(sizeof(Elf64_Ehdr));
elf->e_shoff = 0;
elf->e_flags = 0;
elf->e_ehsize = cpu_to_be16(sizeof(Elf64_Ehdr));
elf->e_phentsize = cpu_to_be16(sizeof(Elf64_Phdr));
elf->e_phnum = 0;
elf->e_shentsize = 0;
elf->e_shnum = 0;
elf->e_shstrndx = 0;
phdr = (Elf64_Phdr *)bufp;
bufp += sizeof(Elf64_Phdr);
phdr->p_type = cpu_to_be32(PT_NOTE);
phdr->p_flags = 0;
phdr->p_align = 0;
phdr->p_paddr = phdr->p_vaddr = 0;
phdr->p_offset = cpu_to_be64(hdr_size);
phdr->p_filesz = phdr->p_memsz = cpu_to_be64(cpu_notes_size);
count++;
opalcore_off = oc_conf->opalcorebuf_sz;
oc_conf->ptload_phdr = (Elf64_Phdr *)bufp;
paddr = 0;
for (i = 0; i < oc_conf->ptload_cnt; i++) {
phdr = (Elf64_Phdr *)bufp;
bufp += sizeof(Elf64_Phdr);
phdr->p_type = cpu_to_be32(PT_LOAD);
phdr->p_flags = cpu_to_be32(PF_R|PF_W|PF_X);
phdr->p_align = 0;
new = get_new_element();
if (!new)
return -ENOMEM;
new->paddr = oc_conf->ptload_addr[i];
new->size = oc_conf->ptload_size[i];
new->offset = opalcore_off;
list_add_tail(&new->list, &opalcore_list);
phdr->p_paddr = cpu_to_be64(paddr);
phdr->p_vaddr = cpu_to_be64(opal_base_addr + paddr);
phdr->p_filesz = phdr->p_memsz =
cpu_to_be64(oc_conf->ptload_size[i]);
phdr->p_offset = cpu_to_be64(opalcore_off);
count++;
opalcore_off += oc_conf->ptload_size[i];
paddr += oc_conf->ptload_size[i];
}
elf->e_phnum = cpu_to_be16(count);
bufp = (char *)opalcore_append_cpu_notes((Elf64_Word *)bufp);
bufp = (char *)auxv_to_elf64_notes((Elf64_Word *)bufp, opal_boot_entry);
oc_conf->opalcore_size = opalcore_off;
return 0;
}
static void opalcore_cleanup(void)
{
if (oc_conf == NULL)
return;
/* Remove OPAL core sysfs file */
sysfs_remove_bin_file(mpipl_kobj, &opal_core_attr);
oc_conf->ptload_phdr = NULL;
oc_conf->ptload_cnt = 0;
/* free the buffer used for setting up OPAL core */
if (oc_conf->opalcorebuf) {
void *end = (void *)((u64)oc_conf->opalcorebuf +
oc_conf->opalcorebuf_sz);
free_reserved_area(oc_conf->opalcorebuf, end, -1, NULL);
oc_conf->opalcorebuf = NULL;
oc_conf->opalcorebuf_sz = 0;
}
kfree(oc_conf);
oc_conf = NULL;
}
__exitcall(opalcore_cleanup);
static void __init opalcore_config_init(void)
{
u32 idx, cpu_data_version;
struct device_node *np;
const __be32 *prop;
u64 addr = 0;
int i, ret;
np = of_find_node_by_path("/ibm,opal/dump");
if (np == NULL)
return;
if (!of_device_is_compatible(np, "ibm,opal-dump")) {
pr_warn("Support missing for this f/w version!\n");
return;
}
/* Check if dump has been initiated on last reboot */
prop = of_get_property(np, "mpipl-boot", NULL);
if (!prop) {
of_node_put(np);
return;
}
/* Get OPAL metadata */
ret = opal_mpipl_query_tag(OPAL_MPIPL_TAG_OPAL, &addr);
if ((ret != OPAL_SUCCESS) || !addr) {
pr_err("Failed to get OPAL metadata (%d)\n", ret);
goto error_out;
}
addr = be64_to_cpu(addr);
pr_debug("OPAL metadata addr: %llx\n", addr);
opalc_metadata = __va(addr);
/* Get OPAL CPU metadata */
ret = opal_mpipl_query_tag(OPAL_MPIPL_TAG_CPU, &addr);
if ((ret != OPAL_SUCCESS) || !addr) {
pr_err("Failed to get OPAL CPU metadata (%d)\n", ret);
goto error_out;
}
addr = be64_to_cpu(addr);
pr_debug("CPU metadata addr: %llx\n", addr);
opalc_cpu_metadata = __va(addr);
/* Allocate memory for config buffer */
oc_conf = kzalloc(sizeof(struct opalcore_config), GFP_KERNEL);
if (oc_conf == NULL)
goto error_out;
/* Parse OPAL metadata */
if (opalc_metadata->version != OPAL_MPIPL_VERSION) {
pr_warn("Supported OPAL metadata version: %u, found: %u!\n",
OPAL_MPIPL_VERSION, opalc_metadata->version);
pr_warn("WARNING: F/W using newer OPAL metadata format!!\n");
}
oc_conf->ptload_cnt = 0;
idx = be32_to_cpu(opalc_metadata->region_cnt);
if (idx > MAX_PT_LOAD_CNT) {
pr_warn("WARNING: OPAL regions count (%d) adjusted to limit (%d)",
idx, MAX_PT_LOAD_CNT);
idx = MAX_PT_LOAD_CNT;
}
for (i = 0; i < idx; i++) {
oc_conf->ptload_addr[oc_conf->ptload_cnt] =
be64_to_cpu(opalc_metadata->region[i].dest);
oc_conf->ptload_size[oc_conf->ptload_cnt++] =
be64_to_cpu(opalc_metadata->region[i].size);
}
oc_conf->ptload_cnt = i;
oc_conf->crashing_cpu = be32_to_cpu(opalc_metadata->crashing_pir);
if (!oc_conf->ptload_cnt) {
pr_err("OPAL memory regions not found\n");
goto error_out;
}
/* Parse OPAL CPU metadata */
cpu_data_version = be32_to_cpu(opalc_cpu_metadata->cpu_data_version);
if (cpu_data_version != HDAT_FADUMP_CPU_DATA_VER) {
pr_warn("Supported CPU data version: %u, found: %u!\n",
HDAT_FADUMP_CPU_DATA_VER, cpu_data_version);
pr_warn("WARNING: F/W using newer CPU state data format!!\n");
}
addr = be64_to_cpu(opalc_cpu_metadata->region[0].dest);
if (!addr) {
pr_err("CPU state data not found!\n");
goto error_out;
}
oc_conf->cpu_state_destination_vaddr = (u64)__va(addr);
oc_conf->cpu_state_data_size =
be64_to_cpu(opalc_cpu_metadata->region[0].size);
oc_conf->cpu_state_entry_size =
be32_to_cpu(opalc_cpu_metadata->cpu_data_size);
if ((oc_conf->cpu_state_entry_size == 0) ||
(oc_conf->cpu_state_entry_size > oc_conf->cpu_state_data_size)) {
pr_err("CPU state data is invalid.\n");
goto error_out;
}
oc_conf->num_cpus = (oc_conf->cpu_state_data_size /
oc_conf->cpu_state_entry_size);
of_node_put(np);
return;
error_out:
pr_err("Could not export /sys/firmware/opal/core\n");
opalcore_cleanup();
of_node_put(np);
}
static ssize_t release_core_store(struct kobject *kobj,
struct kobj_attribute *attr,
const char *buf, size_t count)
{
int input = -1;
if (kstrtoint(buf, 0, &input))
return -EINVAL;
if (input == 1) {
if (oc_conf == NULL) {
pr_err("'/sys/firmware/opal/core' file not accessible!\n");
return -EPERM;
}
/*
* Take away '/sys/firmware/opal/core' and release all memory
* used for exporting this file.
*/
opalcore_cleanup();
} else
return -EINVAL;
return count;
}
static struct kobj_attribute opalcore_rel_attr = __ATTR_WO(release_core);
static struct attribute *mpipl_attr[] = {
&opalcore_rel_attr.attr,
NULL,
};
static struct bin_attribute *mpipl_bin_attr[] = {
&opal_core_attr,
NULL,
};
static const struct attribute_group mpipl_group = {
.attrs = mpipl_attr,
.bin_attrs = mpipl_bin_attr,
};
static int __init opalcore_init(void)
{
int rc = -1;
opalcore_config_init();
if (oc_conf == NULL)
return rc;
create_opalcore();
/*
* If oc_conf->opalcorebuf= is set in the 2nd kernel,
* then capture the dump.
*/
if (!(is_opalcore_usable())) {
pr_err("Failed to export /sys/firmware/opal/mpipl/core\n");
opalcore_cleanup();
return rc;
}
/* Set OPAL core file size */
opal_core_attr.size = oc_conf->opalcore_size;
mpipl_kobj = kobject_create_and_add("mpipl", opal_kobj);
if (!mpipl_kobj) {
pr_err("unable to create mpipl kobject\n");
return -ENOMEM;
}
/* Export OPAL core sysfs file */
rc = sysfs_create_group(mpipl_kobj, &mpipl_group);
if (rc) {
pr_err("mpipl sysfs group creation failed (%d)", rc);
opalcore_cleanup();
return rc;
}
/* The /sys/firmware/opal/core is moved to /sys/firmware/opal/mpipl/
* directory, need to create symlink at old location to maintain
* backward compatibility.
*/
rc = compat_only_sysfs_link_entry_to_kobj(opal_kobj, mpipl_kobj,
"core", NULL);
if (rc) {
pr_err("unable to create core symlink (%d)\n", rc);
return rc;
}
return 0;
}
fs_initcall(opalcore_init);