/*
* Firmware Assisted dump: A robust mechanism to get reliable kernel crash
* dump with assistance from firmware. This approach does not use kexec,
* instead firmware assists in booting the kdump kernel while preserving
* memory contents. The most of the code implementation has been adapted
* from phyp assisted dump implementation written by Linas Vepstas and
* Manish Ahuja
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* Copyright 2011 IBM Corporation
* Author: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
*/
#undef DEBUG
#define pr_fmt(fmt) "fadump: " fmt
#include <linux/string.h>
#include <linux/memblock.h>
#include <linux/delay.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>
#include <linux/crash_dump.h>
#include <linux/kobject.h>
#include <linux/sysfs.h>
#include <asm/page.h>
#include <asm/prom.h>
#include <asm/rtas.h>
#include <asm/fadump.h>
#include <asm/debug.h>
#include <asm/setup.h>
static struct fw_dump fw_dump;
static struct fadump_mem_struct fdm;
static const struct fadump_mem_struct *fdm_active;
static DEFINE_MUTEX(fadump_mutex);
struct fad_crash_memory_ranges crash_memory_ranges[INIT_CRASHMEM_RANGES];
int crash_mem_ranges;
/* Scan the Firmware Assisted dump configuration details. */
int __init early_init_dt_scan_fw_dump(unsigned long node,
const char *uname, int depth, void *data)
{
__be32 *sections;
int i, num_sections;
unsigned long size;
const int *token;
if (depth != 1 || strcmp(uname, "rtas") != 0)
return 0;
/*
* Check if Firmware Assisted dump is supported. if yes, check
* if dump has been initiated on last reboot.
*/
token = of_get_flat_dt_prop(node, "ibm,configure-kernel-dump", NULL);
if (!token)
return 0;
fw_dump.fadump_supported = 1;
fw_dump.ibm_configure_kernel_dump = *token;
/*
* The 'ibm,kernel-dump' rtas node is present only if there is
* dump data waiting for us.
*/
fdm_active = of_get_flat_dt_prop(node, "ibm,kernel-dump", NULL);
if (fdm_active)
fw_dump.dump_active = 1;
/* Get the sizes required to store dump data for the firmware provided
* dump sections.
* For each dump section type supported, a 32bit cell which defines
* the ID of a supported section followed by two 32 bit cells which
* gives teh size of the section in bytes.
*/
sections = of_get_flat_dt_prop(node, "ibm,configure-kernel-dump-sizes",
&size);
if (!sections)
return 0;
num_sections = size / (3 * sizeof(u32));
for (i = 0; i < num_sections; i++, sections += 3) {
u32 type = (u32)of_read_number(sections, 1);
switch (type) {
case FADUMP_CPU_STATE_DATA:
fw_dump.cpu_state_data_size =
of_read_ulong(§ions[1], 2);
break;
case FADUMP_HPTE_REGION:
fw_dump.hpte_region_size =
of_read_ulong(§ions[1], 2);
break;
}
}
return 1;
}
int is_fadump_active(void)
{
return fw_dump.dump_active;
}
/* Print firmware assisted dump configurations for debugging purpose. */
static void fadump_show_config(void)
{
pr_debug("Support for firmware-assisted dump (fadump): %s\n",
(fw_dump.fadump_supported ? "present" : "no support"));
if (!fw_dump.fadump_supported)
return;
pr_debug("Fadump enabled : %s\n",
(fw_dump.fadump_enabled ? "yes" : "no"));
pr_debug("Dump Active : %s\n",
(fw_dump.dump_active ? "yes" : "no"));
pr_debug("Dump section sizes:\n");
pr_debug(" CPU state data size: %lx\n", fw_dump.cpu_state_data_size);
pr_debug(" HPTE region size : %lx\n", fw_dump.hpte_region_size);
pr_debug("Boot memory size : %lx\n", fw_dump.boot_memory_size);
}
static unsigned long init_fadump_mem_struct(struct fadump_mem_struct *fdm,
unsigned long addr)
{
if (!fdm)
return 0;
memset(fdm, 0, sizeof(struct fadump_mem_struct));
addr = addr & PAGE_MASK;
fdm->header.dump_format_version = 0x00000001;
fdm->header.dump_num_sections = 3;
fdm->header.dump_status_flag = 0;
fdm->header.offset_first_dump_section =
(u32)offsetof(struct fadump_mem_struct, cpu_state_data);
/*
* Fields for disk dump option.
* We are not using disk dump option, hence set these fields to 0.
*/
fdm->header.dd_block_size = 0;
fdm->header.dd_block_offset = 0;
fdm->header.dd_num_blocks = 0;
fdm->header.dd_offset_disk_path = 0;
/* set 0 to disable an automatic dump-reboot. */
fdm->header.max_time_auto = 0;
/* Kernel dump sections */
/* cpu state data section. */
fdm->cpu_state_data.request_flag = FADUMP_REQUEST_FLAG;
fdm->cpu_state_data.source_data_type = FADUMP_CPU_STATE_DATA;
fdm->cpu_state_data.source_address = 0;
fdm->cpu_state_data.source_len = fw_dump.cpu_state_data_size;
fdm->cpu_state_data.destination_address = addr;
addr += fw_dump.cpu_state_data_size;
/* hpte region section */
fdm->hpte_region.request_flag = FADUMP_REQUEST_FLAG;
fdm->hpte_region.source_data_type = FADUMP_HPTE_REGION;
fdm->hpte_region.source_address = 0;
fdm->hpte_region.source_len = fw_dump.hpte_region_size;
fdm->hpte_region.destination_address = addr;
addr += fw_dump.hpte_region_size;
/* RMA region section */
fdm->rmr_region.request_flag = FADUMP_REQUEST_FLAG;
fdm->rmr_region.source_data_type = FADUMP_REAL_MODE_REGION;
fdm->rmr_region.source_address = RMA_START;
fdm->rmr_region.source_len = fw_dump.boot_memory_size;
fdm->rmr_region.destination_address = addr;
addr += fw_dump.boot_memory_size;
return addr;
}
/**
* fadump_calculate_reserve_size(): reserve variable boot area 5% of System RAM
*
* Function to find the largest memory size we need to reserve during early
* boot process. This will be the size of the memory that is required for a
* kernel to boot successfully.
*
* This function has been taken from phyp-assisted dump feature implementation.
*
* returns larger of 256MB or 5% rounded down to multiples of 256MB.
*
* TODO: Come up with better approach to find out more accurate memory size
* that is required for a kernel to boot successfully.
*
*/
static inline unsigned long fadump_calculate_reserve_size(void)
{
unsigned long size;
/*
* Check if the size is specified through fadump_reserve_mem= cmdline
* option. If yes, then use that.
*/
if (fw_dump.reserve_bootvar)
return fw_dump.reserve_bootvar;
/* divide by 20 to get 5% of value */
size = memblock_end_of_DRAM() / 20;
/* round it down in multiples of 256 */
size = size & ~0x0FFFFFFFUL;
/* Truncate to memory_limit. We don't want to over reserve the memory.*/
if (memory_limit && size > memory_limit)
size = memory_limit;
return (size > MIN_BOOT_MEM ? size : MIN_BOOT_MEM);
}
/*
* Calculate the total memory size required to be reserved for
* firmware-assisted dump registration.
*/
static unsigned long get_fadump_area_size(void)
{
unsigned long size = 0;
size += fw_dump.cpu_state_data_size;
size += fw_dump.hpte_region_size;
size += fw_dump.boot_memory_size;
size += sizeof(struct fadump_crash_info_header);
size += sizeof(struct elfhdr); /* ELF core header.*/
size += sizeof(struct elf_phdr); /* place holder for cpu notes */
/* Program headers for crash memory regions. */
size += sizeof(struct elf_phdr) * (memblock_num_regions(memory) + 2);
size = PAGE_ALIGN(size);
return size;
}
int __init fadump_reserve_mem(void)
{
unsigned long base, size, memory_boundary;
if (!fw_dump.fadump_enabled)
return 0;
if (!fw_dump.fadump_supported) {
printk(KERN_INFO "Firmware-assisted dump is not supported on"
" this hardware\n");
fw_dump.fadump_enabled = 0;
return 0;
}
/*
* Initialize boot memory size
* If dump is active then we have already calculated the size during
* first kernel.
*/
if (fdm_active)
fw_dump.boot_memory_size = fdm_active->rmr_region.source_len;
else
fw_dump.boot_memory_size = fadump_calculate_reserve_size();
/*
* Calculate the memory boundary.
* If memory_limit is less than actual memory boundary then reserve
* the memory for fadump beyond the memory_limit and adjust the
* memory_limit accordingly, so that the running kernel can run with
* specified memory_limit.
*/
if (memory_limit && memory_limit < memblock_end_of_DRAM()) {
size = get_fadump_area_size();
if ((memory_limit + size) < memblock_end_of_DRAM())
memory_limit += size;
else
memory_limit = memblock_end_of_DRAM();
printk(KERN_INFO "Adjusted memory_limit for firmware-assisted"
" dump, now %#016llx\n", memory_limit);
}
if (memory_limit)
memory_boundary = memory_limit;
else
memory_boundary = memblock_end_of_DRAM();
if (fw_dump.dump_active) {
printk(KERN_INFO "Firmware-assisted dump is active.\n");
/*
* If last boot has crashed then reserve all the memory
* above boot_memory_size so that we don't touch it until
* dump is written to disk by userspace tool. This memory
* will be released for general use once the dump is saved.
*/
base = fw_dump.boot_memory_size;
size = memory_boundary - base;
memblock_reserve(base, size);
printk(KERN_INFO "Reserved %ldMB of memory at %ldMB "
"for saving crash dump\n",
(unsigned long)(size >> 20),
(unsigned long)(base >> 20));
fw_dump.fadumphdr_addr =
fdm_active->rmr_region.destination_address +
fdm_active->rmr_region.source_len;
pr_debug("fadumphdr_addr = %p\n",
(void *) fw_dump.fadumphdr_addr);
} else {
/* Reserve the memory at the top of memory. */
size = get_fadump_area_size();
base = memory_boundary - size;
memblock_reserve(base, size);
printk(KERN_INFO "Reserved %ldMB of memory at %ldMB "
"for firmware-assisted dump\n",
(unsigned long)(size >> 20),
(unsigned long)(base >> 20));
}
fw_dump.reserve_dump_area_start = base;
fw_dump.reserve_dump_area_size = size;
return 1;
}
/* Look for fadump= cmdline option. */
static int __init early_fadump_param(char *p)
{
if (!p)
return 1;
if (strncmp(p, "on", 2) == 0)
fw_dump.fadump_enabled = 1;
else if (strncmp(p, "off", 3) == 0)
fw_dump.fadump_enabled = 0;
return 0;
}
early_param("fadump", early_fadump_param);
/* Look for fadump_reserve_mem= cmdline option */
static int __init early_fadump_reserve_mem(char *p)
{
if (p)
fw_dump.reserve_bootvar = memparse(p, &p);
return 0;
}
early_param("fadump_reserve_mem", early_fadump_reserve_mem);
static void register_fw_dump(struct fadump_mem_struct *fdm)
{
int rc;
unsigned int wait_time;
pr_debug("Registering for firmware-assisted kernel dump...\n");
/* TODO: Add upper time limit for the delay */
do {
rc = rtas_call(fw_dump.ibm_configure_kernel_dump, 3, 1, NULL,
FADUMP_REGISTER, fdm,
sizeof(struct fadump_mem_struct));
wait_time = rtas_busy_delay_time(rc);
if (wait_time)
mdelay(wait_time);
} while (wait_time);
switch (rc) {
case -1:
printk(KERN_ERR "Failed to register firmware-assisted kernel"
" dump. Hardware Error(%d).\n", rc);
break;
case -3:
printk(KERN_ERR "Failed to register firmware-assisted kernel"
" dump. Parameter Error(%d).\n", rc);
break;
case -9:
printk(KERN_ERR "firmware-assisted kernel dump is already "
" registered.");
fw_dump.dump_registered = 1;
break;
case 0:
printk(KERN_INFO "firmware-assisted kernel dump registration"
" is successful\n");
fw_dump.dump_registered = 1;
break;
}
}
void crash_fadump(struct pt_regs *regs, const char *str)
{
struct fadump_crash_info_header *fdh = NULL;
if (!fw_dump.dump_registered || !fw_dump.fadumphdr_addr)
return;
fdh = __va(fw_dump.fadumphdr_addr);
crashing_cpu = smp_processor_id();
fdh->crashing_cpu = crashing_cpu;
crash_save_vmcoreinfo();
if (regs)
fdh->regs = *regs;
else
ppc_save_regs(&fdh->regs);
fdh->cpu_online_mask = *cpu_online_mask;
/* Call ibm,os-term rtas call to trigger firmware assisted dump */
rtas_os_term((char *)str);
}
#define GPR_MASK 0xffffff0000000000
static inline int fadump_gpr_index(u64 id)
{
int i = -1;
char str[3];
if ((id & GPR_MASK) == REG_ID("GPR")) {
/* get the digits at the end */
id &= ~GPR_MASK;
id >>= 24;
str[2] = '\0';
str[1] = id & 0xff;
str[0] = (id >> 8) & 0xff;
sscanf(str, "%d", &i);
if (i > 31)
i = -1;
}
return i;
}
static inline void fadump_set_regval(struct pt_regs *regs, u64 reg_id,
u64 reg_val)
{
int i;
i = fadump_gpr_index(reg_id);
if (i >= 0)
regs->gpr[i] = (unsigned long)reg_val;
else if (reg_id == REG_ID("NIA"))
regs->nip = (unsigned long)reg_val;
else if (reg_id == REG_ID("MSR"))
regs->msr = (unsigned long)reg_val;
else if (reg_id == REG_ID("CTR"))
regs->ctr = (unsigned long)reg_val;
else if (reg_id == REG_ID("LR"))
regs->link = (unsigned long)reg_val;
else if (reg_id == REG_ID("XER"))
regs->xer = (unsigned long)reg_val;
else if (reg_id == REG_ID("CR"))
regs->ccr = (unsigned long)reg_val;
else if (reg_id == REG_ID("DAR"))
regs->dar = (unsigned long)reg_val;
else if (reg_id == REG_ID("DSISR"))
regs->dsisr = (unsigned long)reg_val;
}
static struct fadump_reg_entry*
fadump_read_registers(struct fadump_reg_entry *reg_entry, struct pt_regs *regs)
{
memset(regs, 0, sizeof(struct pt_regs));
while (reg_entry->reg_id != REG_ID("CPUEND")) {
fadump_set_regval(regs, reg_entry->reg_id,
reg_entry->reg_value);
reg_entry++;
}
reg_entry++;
return reg_entry;
}
static u32 *fadump_append_elf_note(u32 *buf, char *name, unsigned type,
void *data, size_t data_len)
{
struct elf_note note;
note.n_namesz = strlen(name) + 1;
note.n_descsz = data_len;
note.n_type = type;
memcpy(buf, ¬e, sizeof(note));
buf += (sizeof(note) + 3)/4;
memcpy(buf, name, note.n_namesz);
buf += (note.n_namesz + 3)/4;
memcpy(buf, data, note.n_descsz);
buf += (note.n_descsz + 3)/4;
return buf;
}
static void fadump_final_note(u32 *buf)
{
struct elf_note note;
note.n_namesz = 0;
note.n_descsz = 0;
note.n_type = 0;
memcpy(buf, ¬e, sizeof(note));
}
static u32 *fadump_regs_to_elf_notes(u32 *buf, struct pt_regs *regs)
{
struct elf_prstatus prstatus;
memset(&prstatus, 0, sizeof(prstatus));
/*
* FIXME: How do i get PID? Do I really need it?
* prstatus.pr_pid = ????
*/
elf_core_copy_kernel_regs(&prstatus.pr_reg, regs);
buf = fadump_append_elf_note(buf, KEXEC_CORE_NOTE_NAME, NT_PRSTATUS,
&prstatus, sizeof(prstatus));
return buf;
}
static void fadump_update_elfcore_header(char *bufp)
{
struct elfhdr *elf;
struct elf_phdr *phdr;
elf = (struct elfhdr *)bufp;
bufp += sizeof(struct elfhdr);
/* First note is a place holder for cpu notes info. */
phdr = (struct elf_phdr *)bufp;
if (phdr->p_type == PT_NOTE) {
phdr->p_paddr = fw_dump.cpu_notes_buf;
phdr->p_offset = phdr->p_paddr;
phdr->p_filesz = fw_dump.cpu_notes_buf_size;
phdr->p_memsz = fw_dump.cpu_notes_buf_size;
}
return;
}
static void *fadump_cpu_notes_buf_alloc(unsigned long size)
{
void *vaddr;
struct page *page;
unsigned long order, count, i;
order = get_order(size);
vaddr = (void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, order);
if (!vaddr)
return NULL;
count = 1 << order;
page = virt_to_page(vaddr);
for (i = 0; i < count; i++)
SetPageReserved(page + i);
return vaddr;
}
static void fadump_cpu_notes_buf_free(unsigned long vaddr, unsigned long size)
{
struct page *page;
unsigned long order, count, i;
order = get_order(size);
count = 1 << order;
page = virt_to_page(vaddr);
for (i = 0; i < count; i++)
ClearPageReserved(page + i);
__free_pages(page, order);
}
/*
* Read CPU state dump data and convert it into ELF notes.
* The CPU dump starts with magic number "REGSAVE". NumCpusOffset should be
* used to access the data to allow for additional fields to be added without
* affecting compatibility. Each list of registers for a CPU starts with
* "CPUSTRT" and ends with "CPUEND". Each register entry is of 16 bytes,
* 8 Byte ASCII identifier and 8 Byte register value. The register entry
* with identifier "CPUSTRT" and "CPUEND" contains 4 byte cpu id as part
* of register value. For more details refer to PAPR document.
*
* Only for the crashing cpu we ignore the CPU dump data and get exact
* state from fadump crash info structure populated by first kernel at the
* time of crash.
*/
static int __init fadump_build_cpu_notes(const struct fadump_mem_struct *fdm)
{
struct fadump_reg_save_area_header *reg_header;
struct fadump_reg_entry *reg_entry;
struct fadump_crash_info_header *fdh = NULL;
void *vaddr;
unsigned long addr;
u32 num_cpus, *note_buf;
struct pt_regs regs;
int i, rc = 0, cpu = 0;
if (!fdm->cpu_state_data.bytes_dumped)
return -EINVAL;
addr = fdm->cpu_state_data.destination_address;
vaddr = __va(addr);
reg_header = vaddr;
if (reg_header->magic_number != REGSAVE_AREA_MAGIC) {
printk(KERN_ERR "Unable to read register save area.\n");
return -ENOENT;
}
pr_debug("--------CPU State Data------------\n");
pr_debug("Magic Number: %llx\n", reg_header->magic_number);
pr_debug("NumCpuOffset: %x\n", reg_header->num_cpu_offset);
vaddr += reg_header->num_cpu_offset;
num_cpus = *((u32 *)(vaddr));
pr_debug("NumCpus : %u\n", num_cpus);
vaddr += sizeof(u32);
reg_entry = (struct fadump_reg_entry *)vaddr;
/* Allocate buffer to hold cpu crash notes. */
fw_dump.cpu_notes_buf_size = num_cpus * sizeof(note_buf_t);
fw_dump.cpu_notes_buf_size = PAGE_ALIGN(fw_dump.cpu_notes_buf_size);
note_buf = fadump_cpu_notes_buf_alloc(fw_dump.cpu_notes_buf_size);
if (!note_buf) {
printk(KERN_ERR "Failed to allocate 0x%lx bytes for "
"cpu notes buffer\n", fw_dump.cpu_notes_buf_size);
return -ENOMEM;
}
fw_dump.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 (fw_dump.fadumphdr_addr)
fdh = __va(fw_dump.fadumphdr_addr);
for (i = 0; i < num_cpus; i++) {
if (reg_entry->reg_id != REG_ID("CPUSTRT")) {
printk(KERN_ERR "Unable to read CPU state data\n");
rc = -ENOENT;
goto error_out;
}
/* Lower 4 bytes of reg_value contains logical cpu id */
cpu = reg_entry->reg_value & FADUMP_CPU_ID_MASK;
if (!cpumask_test_cpu(cpu, &fdh->cpu_online_mask)) {
SKIP_TO_NEXT_CPU(reg_entry);
continue;
}
pr_debug("Reading register data for cpu %d...\n", cpu);
if (fdh && fdh->crashing_cpu == cpu) {
regs = fdh->regs;
note_buf = fadump_regs_to_elf_notes(note_buf, ®s);
SKIP_TO_NEXT_CPU(reg_entry);
} else {
reg_entry++;
reg_entry = fadump_read_registers(reg_entry, ®s);
note_buf = fadump_regs_to_elf_notes(note_buf, ®s);
}
}
fadump_final_note(note_buf);
pr_debug("Updating elfcore header (%llx) with cpu notes\n",
fdh->elfcorehdr_addr);
fadump_update_elfcore_header((char *)__va(fdh->elfcorehdr_addr));
return 0;
error_out:
fadump_cpu_notes_buf_free((unsigned long)__va(fw_dump.cpu_notes_buf),
fw_dump.cpu_notes_buf_size);
fw_dump.cpu_notes_buf = 0;
fw_dump.cpu_notes_buf_size = 0;
return rc;
}
/*
* Validate and process the dump data stored by firmware before exporting
* it through '/proc/vmcore'.
*/
static int __init process_fadump(const struct fadump_mem_struct *fdm_active)
{
struct fadump_crash_info_header *fdh;
int rc = 0;
if (!fdm_active || !fw_dump.fadumphdr_addr)
return -EINVAL;
/* Check if the dump data is valid. */
if ((fdm_active->header.dump_status_flag == FADUMP_ERROR_FLAG) ||
(fdm_active->cpu_state_data.error_flags != 0) ||
(fdm_active->rmr_region.error_flags != 0)) {
printk(KERN_ERR "Dump taken by platform is not valid\n");
return -EINVAL;
}
if ((fdm_active->rmr_region.bytes_dumped !=
fdm_active->rmr_region.source_len) ||
!fdm_active->cpu_state_data.bytes_dumped) {
printk(KERN_ERR "Dump taken by platform is incomplete\n");
return -EINVAL;
}
/* Validate the fadump crash info header */
fdh = __va(fw_dump.fadumphdr_addr);
if (fdh->magic_number != FADUMP_CRASH_INFO_MAGIC) {
printk(KERN_ERR "Crash info header is not valid.\n");
return -EINVAL;
}
rc = fadump_build_cpu_notes(fdm_active);
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 0;
}
static inline void fadump_add_crash_memory(unsigned long long base,
unsigned long long end)
{
if (base == end)
return;
pr_debug("crash_memory_range[%d] [%#016llx-%#016llx], %#llx bytes\n",
crash_mem_ranges, base, end - 1, (end - base));
crash_memory_ranges[crash_mem_ranges].base = base;
crash_memory_ranges[crash_mem_ranges].size = end - base;
crash_mem_ranges++;
}
static void fadump_exclude_reserved_area(unsigned long long start,
unsigned long long end)
{
unsigned long long ra_start, ra_end;
ra_start = fw_dump.reserve_dump_area_start;
ra_end = ra_start + fw_dump.reserve_dump_area_size;
if ((ra_start < end) && (ra_end > start)) {
if ((start < ra_start) && (end > ra_end)) {
fadump_add_crash_memory(start, ra_start);
fadump_add_crash_memory(ra_end, end);
} else if (start < ra_start) {
fadump_add_crash_memory(start, ra_start);
} else if (ra_end < end) {
fadump_add_crash_memory(ra_end, end);
}
} else
fadump_add_crash_memory(start, end);
}
static int fadump_init_elfcore_header(char *bufp)
{
struct elfhdr *elf;
elf = (struct elfhdr *) bufp;
bufp += sizeof(struct elfhdr);
memcpy(elf->e_ident, ELFMAG, SELFMAG);
elf->e_ident[EI_CLASS] = ELF_CLASS;
elf->e_ident[EI_DATA] = ELF_DATA;
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 = ET_CORE;
elf->e_machine = ELF_ARCH;
elf->e_version = EV_CURRENT;
elf->e_entry = 0;
elf->e_phoff = sizeof(struct elfhdr);
elf->e_shoff = 0;
elf->e_flags = ELF_CORE_EFLAGS;
elf->e_ehsize = sizeof(struct elfhdr);
elf->e_phentsize = sizeof(struct elf_phdr);
elf->e_phnum = 0;
elf->e_shentsize = 0;
elf->e_shnum = 0;
elf->e_shstrndx = 0;
return 0;
}
/*
* Traverse through memblock structure and setup crash memory ranges. These
* ranges will be used create PT_LOAD program headers in elfcore header.
*/
static void fadump_setup_crash_memory_ranges(void)
{
struct memblock_region *reg;
unsigned long long start, end;
pr_debug("Setup crash memory ranges.\n");
crash_mem_ranges = 0;
/*
* add the first memory chunk (RMA_START through boot_memory_size) as
* a separate memory chunk. The reason is, at the time crash firmware
* will move the content of this memory chunk to different location
* specified during fadump registration. We need to create a separate
* program header for this chunk with the correct offset.
*/
fadump_add_crash_memory(RMA_START, fw_dump.boot_memory_size);
for_each_memblock(memory, reg) {
start = (unsigned long long)reg->base;
end = start + (unsigned long long)reg->size;
if (start == RMA_START && end >= fw_dump.boot_memory_size)
start = fw_dump.boot_memory_size;
/* add this range excluding the reserved dump area. */
fadump_exclude_reserved_area(start, end);
}
}
/*
* If the given physical address falls within the boot memory region then
* return the relocated address that points to the dump region reserved
* for saving initial boot memory contents.
*/
static inline unsigned long fadump_relocate(unsigned long paddr)
{
if (paddr > RMA_START && paddr < fw_dump.boot_memory_size)
return fdm.rmr_region.destination_address + paddr;
else
return paddr;
}
static int fadump_create_elfcore_headers(char *bufp)
{
struct elfhdr *elf;
struct elf_phdr *phdr;
int i;
fadump_init_elfcore_header(bufp);
elf = (struct elfhdr *)bufp;
bufp += sizeof(struct elfhdr);
/*
* setup ELF PT_NOTE, place holder for cpu notes info. The notes info
* will be populated during second kernel boot after crash. Hence
* this PT_NOTE will always be the first elf note.
*
* NOTE: Any new ELF note addition should be placed after this note.
*/
phdr = (struct elf_phdr *)bufp;
bufp += sizeof(struct elf_phdr);
phdr->p_type = PT_NOTE;
phdr->p_flags = 0;
phdr->p_vaddr = 0;
phdr->p_align = 0;
phdr->p_offset = 0;
phdr->p_paddr = 0;
phdr->p_filesz = 0;
phdr->p_memsz = 0;
(elf->e_phnum)++;
/* setup ELF PT_NOTE for vmcoreinfo */
phdr = (struct elf_phdr *)bufp;
bufp += sizeof(struct elf_phdr);
phdr->p_type = PT_NOTE;
phdr->p_flags = 0;
phdr->p_vaddr = 0;
phdr->p_align = 0;
phdr->p_paddr = fadump_relocate(paddr_vmcoreinfo_note());
phdr->p_offset = phdr->p_paddr;
phdr->p_memsz = vmcoreinfo_max_size;
phdr->p_filesz = vmcoreinfo_max_size;
/* Increment number of program headers. */
(elf->e_phnum)++;
/* setup PT_LOAD sections. */
for (i = 0; i < crash_mem_ranges; i++) {
unsigned long long mbase, msize;
mbase = crash_memory_ranges[i].base;
msize = crash_memory_ranges[i].size;
if (!msize)
continue;
phdr = (struct elf_phdr *)bufp;
bufp += sizeof(struct elf_phdr);
phdr->p_type = PT_LOAD;
phdr->p_flags = PF_R|PF_W|PF_X;
phdr->p_offset = mbase;
if (mbase == RMA_START) {
/*
* The entire RMA region will be moved by firmware
* to the specified destination_address. Hence set
* the correct offset.
*/
phdr->p_offset = fdm.rmr_region.destination_address;
}
phdr->p_paddr = mbase;
phdr->p_vaddr = (unsigned long)__va(mbase);
phdr->p_filesz = msize;
phdr->p_memsz = msize;
phdr->p_align = 0;
/* Increment number of program headers. */
(elf->e_phnum)++;
}
return 0;
}
static unsigned long init_fadump_header(unsigned long addr)
{
struct fadump_crash_info_header *fdh;
if (!addr)
return 0;
fw_dump.fadumphdr_addr = addr;
fdh = __va(addr);
addr += sizeof(struct fadump_crash_info_header);
memset(fdh, 0, sizeof(struct fadump_crash_info_header));
fdh->magic_number = FADUMP_CRASH_INFO_MAGIC;
fdh->elfcorehdr_addr = addr;
/* We will set the crashing cpu id in crash_fadump() during crash. */
fdh->crashing_cpu = CPU_UNKNOWN;
return addr;
}
static void register_fadump(void)
{
unsigned long addr;
void *vaddr;
/*
* If no memory is reserved then we can not register for firmware-
* assisted dump.
*/
if (!fw_dump.reserve_dump_area_size)
return;
fadump_setup_crash_memory_ranges();
addr = fdm.rmr_region.destination_address + fdm.rmr_region.source_len;
/* Initialize fadump crash info header. */
addr = init_fadump_header(addr);
vaddr = __va(addr);
pr_debug("Creating ELF core headers at %#016lx\n", addr);
fadump_create_elfcore_headers(vaddr);
/* register the future kernel dump with firmware. */
register_fw_dump(&fdm);
}
static int fadump_unregister_dump(struct fadump_mem_struct *fdm)
{
int rc = 0;
unsigned int wait_time;
pr_debug("Un-register firmware-assisted dump\n");
/* TODO: Add upper time limit for the delay */
do {
rc = rtas_call(fw_dump.ibm_configure_kernel_dump, 3, 1, NULL,
FADUMP_UNREGISTER, fdm,
sizeof(struct fadump_mem_struct));
wait_time = rtas_busy_delay_time(rc);
if (wait_time)
mdelay(wait_time);
} while (wait_time);
if (rc) {
printk(KERN_ERR "Failed to un-register firmware-assisted dump."
" unexpected error(%d).\n", rc);
return rc;
}
fw_dump.dump_registered = 0;
return 0;
}
static int fadump_invalidate_dump(struct fadump_mem_struct *fdm)
{
int rc = 0;
unsigned int wait_time;
pr_debug("Invalidating firmware-assisted dump registration\n");
/* TODO: Add upper time limit for the delay */
do {
rc = rtas_call(fw_dump.ibm_configure_kernel_dump, 3, 1, NULL,
FADUMP_INVALIDATE, fdm,
sizeof(struct fadump_mem_struct));
wait_time = rtas_busy_delay_time(rc);
if (wait_time)
mdelay(wait_time);
} while (wait_time);
if (rc) {
printk(KERN_ERR "Failed to invalidate firmware-assisted dump "
"rgistration. unexpected error(%d).\n", rc);
return rc;
}
fw_dump.dump_active = 0;
fdm_active = NULL;
return 0;
}
void fadump_cleanup(void)
{
/* Invalidate the registration only if dump is active. */
if (fw_dump.dump_active) {
init_fadump_mem_struct(&fdm,
fdm_active->cpu_state_data.destination_address);
fadump_invalidate_dump(&fdm);
}
}
/*
* Release the memory that was reserved in early boot to preserve the memory
* contents. The released memory will be available for general use.
*/
static void fadump_release_memory(unsigned long begin, unsigned long end)
{
unsigned long addr;
unsigned long ra_start, ra_end;
ra_start = fw_dump.reserve_dump_area_start;
ra_end = ra_start + fw_dump.reserve_dump_area_size;
for (addr = begin; addr < end; addr += PAGE_SIZE) {
/*
* exclude the dump reserve area. Will reuse it for next
* fadump registration.
*/
if (addr <= ra_end && ((addr + PAGE_SIZE) > ra_start))
continue;
free_reserved_page(pfn_to_page(addr >> PAGE_SHIFT));
}
}
static void fadump_invalidate_release_mem(void)
{
unsigned long reserved_area_start, reserved_area_end;
unsigned long destination_address;
mutex_lock(&fadump_mutex);
if (!fw_dump.dump_active) {
mutex_unlock(&fadump_mutex);
return;
}
destination_address = fdm_active->cpu_state_data.destination_address;
fadump_cleanup();
mutex_unlock(&fadump_mutex);
/*
* Save the current reserved memory bounds we will require them
* later for releasing the memory for general use.
*/
reserved_area_start = fw_dump.reserve_dump_area_start;
reserved_area_end = reserved_area_start +
fw_dump.reserve_dump_area_size;
/*
* Setup reserve_dump_area_start and its size so that we can
* reuse this reserved memory for Re-registration.
*/
fw_dump.reserve_dump_area_start = destination_address;
fw_dump.reserve_dump_area_size = get_fadump_area_size();
fadump_release_memory(reserved_area_start, reserved_area_end);
if (fw_dump.cpu_notes_buf) {
fadump_cpu_notes_buf_free(
(unsigned long)__va(fw_dump.cpu_notes_buf),
fw_dump.cpu_notes_buf_size);
fw_dump.cpu_notes_buf = 0;
fw_dump.cpu_notes_buf_size = 0;
}
/* Initialize the kernel dump memory structure for FAD registration. */
init_fadump_mem_struct(&fdm, fw_dump.reserve_dump_area_start);
}
static ssize_t fadump_release_memory_store(struct kobject *kobj,
struct kobj_attribute *attr,
const char *buf, size_t count)
{
if (!fw_dump.dump_active)
return -EPERM;
if (buf[0] == '1') {
/*
* Take away the '/proc/vmcore'. We are releasing the dump
* memory, hence it will not be valid anymore.
*/
vmcore_cleanup();
fadump_invalidate_release_mem();
} else
return -EINVAL;
return count;
}
static ssize_t fadump_enabled_show(struct kobject *kobj,
struct kobj_attribute *attr,
char *buf)
{
return sprintf(buf, "%d\n", fw_dump.fadump_enabled);
}
static ssize_t fadump_register_show(struct kobject *kobj,
struct kobj_attribute *attr,
char *buf)
{
return sprintf(buf, "%d\n", fw_dump.dump_registered);
}
static ssize_t fadump_register_store(struct kobject *kobj,
struct kobj_attribute *attr,
const char *buf, size_t count)
{
int ret = 0;
if (!fw_dump.fadump_enabled || fdm_active)
return -EPERM;
mutex_lock(&fadump_mutex);
switch (buf[0]) {
case '0':
if (fw_dump.dump_registered == 0) {
ret = -EINVAL;
goto unlock_out;
}
/* Un-register Firmware-assisted dump */
fadump_unregister_dump(&fdm);
break;
case '1':
if (fw_dump.dump_registered == 1) {
ret = -EINVAL;
goto unlock_out;
}
/* Register Firmware-assisted dump */
register_fadump();
break;
default:
ret = -EINVAL;
break;
}
unlock_out:
mutex_unlock(&fadump_mutex);
return ret < 0 ? ret : count;
}
static int fadump_region_show(struct seq_file *m, void *private)
{
const struct fadump_mem_struct *fdm_ptr;
if (!fw_dump.fadump_enabled)
return 0;
mutex_lock(&fadump_mutex);
if (fdm_active)
fdm_ptr = fdm_active;
else {
mutex_unlock(&fadump_mutex);
fdm_ptr = &fdm;
}
seq_printf(m,
"CPU : [%#016llx-%#016llx] %#llx bytes, "
"Dumped: %#llx\n",
fdm_ptr->cpu_state_data.destination_address,
fdm_ptr->cpu_state_data.destination_address +
fdm_ptr->cpu_state_data.source_len - 1,
fdm_ptr->cpu_state_data.source_len,
fdm_ptr->cpu_state_data.bytes_dumped);
seq_printf(m,
"HPTE: [%#016llx-%#016llx] %#llx bytes, "
"Dumped: %#llx\n",
fdm_ptr->hpte_region.destination_address,
fdm_ptr->hpte_region.destination_address +
fdm_ptr->hpte_region.source_len - 1,
fdm_ptr->hpte_region.source_len,
fdm_ptr->hpte_region.bytes_dumped);
seq_printf(m,
"DUMP: [%#016llx-%#016llx] %#llx bytes, "
"Dumped: %#llx\n",
fdm_ptr->rmr_region.destination_address,
fdm_ptr->rmr_region.destination_address +
fdm_ptr->rmr_region.source_len - 1,
fdm_ptr->rmr_region.source_len,
fdm_ptr->rmr_region.bytes_dumped);
if (!fdm_active ||
(fw_dump.reserve_dump_area_start ==
fdm_ptr->cpu_state_data.destination_address))
goto out;
/* Dump is active. Show reserved memory region. */
seq_printf(m,
" : [%#016llx-%#016llx] %#llx bytes, "
"Dumped: %#llx\n",
(unsigned long long)fw_dump.reserve_dump_area_start,
fdm_ptr->cpu_state_data.destination_address - 1,
fdm_ptr->cpu_state_data.destination_address -
fw_dump.reserve_dump_area_start,
fdm_ptr->cpu_state_data.destination_address -
fw_dump.reserve_dump_area_start);
out:
if (fdm_active)
mutex_unlock(&fadump_mutex);
return 0;
}
static struct kobj_attribute fadump_release_attr = __ATTR(fadump_release_mem,
0200, NULL,
fadump_release_memory_store);
static struct kobj_attribute fadump_attr = __ATTR(fadump_enabled,
0444, fadump_enabled_show,
NULL);
static struct kobj_attribute fadump_register_attr = __ATTR(fadump_registered,
0644, fadump_register_show,
fadump_register_store);
static int fadump_region_open(struct inode *inode, struct file *file)
{
return single_open(file, fadump_region_show, inode->i_private);
}
static const struct file_operations fadump_region_fops = {
.open = fadump_region_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
static void fadump_init_files(void)
{
struct dentry *debugfs_file;
int rc = 0;
rc = sysfs_create_file(kernel_kobj, &fadump_attr.attr);
if (rc)
printk(KERN_ERR "fadump: unable to create sysfs file"
" fadump_enabled (%d)\n", rc);
rc = sysfs_create_file(kernel_kobj, &fadump_register_attr.attr);
if (rc)
printk(KERN_ERR "fadump: unable to create sysfs file"
" fadump_registered (%d)\n", rc);
debugfs_file = debugfs_create_file("fadump_region", 0444,
powerpc_debugfs_root, NULL,
&fadump_region_fops);
if (!debugfs_file)
printk(KERN_ERR "fadump: unable to create debugfs file"
" fadump_region\n");
if (fw_dump.dump_active) {
rc = sysfs_create_file(kernel_kobj, &fadump_release_attr.attr);
if (rc)
printk(KERN_ERR "fadump: unable to create sysfs file"
" fadump_release_mem (%d)\n", rc);
}
return;
}
/*
* Prepare for firmware-assisted dump.
*/
int __init setup_fadump(void)
{
if (!fw_dump.fadump_enabled)
return 0;
if (!fw_dump.fadump_supported) {
printk(KERN_ERR "Firmware-assisted dump is not supported on"
" this hardware\n");
return 0;
}
fadump_show_config();
/*
* If dump data is available then see if it is valid and prepare for
* saving it to the disk.
*/
if (fw_dump.dump_active) {
/*
* if dump process fails then invalidate the registration
* and release memory before proceeding for re-registration.
*/
if (process_fadump(fdm_active) < 0)
fadump_invalidate_release_mem();
}
/* Initialize the kernel dump memory structure for FAD registration. */
else if (fw_dump.reserve_dump_area_size)
init_fadump_mem_struct(&fdm, fw_dump.reserve_dump_area_start);
fadump_init_files();
return 1;
}
subsys_initcall(setup_fadump);