linux/arch/powerpc/kernel/fadump.c

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/*
* 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>
fadump: Initialize elfcore header and add PT_LOAD program headers. Build the crash memory range list by traversing through system memory during the first kernel before we register for firmware-assisted dump. After the successful dump registration, initialize the elfcore header and populate PT_LOAD program headers with crash memory ranges. The elfcore header is saved in the scratch area within the reserved memory. The scratch area starts at the end of the memory reserved for saving RMR region contents. The scratch area contains fadump crash info structure that contains magic number for fadump validation and physical address where the eflcore header can be found. This structure will also be used to pass some important crash info data to the second kernel which will help second kernel to populate ELF core header with correct data before it gets exported through /proc/vmcore. Since the firmware preserves the entire partition memory at the time of crash the contents of the scratch area will be preserved till second kernel boot. Since the memory dump exported through /proc/vmcore is in ELF format similar to kdump, it will help us to reuse the kdump infrastructure for dump capture and filtering. Unlike phyp dump, userspace tool does not need to refer any sysfs interface while reading /proc/vmcore. NOTE: The current design implementation does not address a possibility of introducing additional fields (in future) to this structure without affecting compatibility. It's on TODO list to come up with better approach to address this. Reserved dump area start => +-------------------------------------+ | CPU state dump data | +-------------------------------------+ | HPTE region data | +-------------------------------------+ | RMR region data | Scratch area start => +-------------------------------------+ | fadump crash info structure { | | magic nummber | +------|---- elfcorehdr_addr | | | } | +----> +-------------------------------------+ | ELF core header | Reserved dump area end => +-------------------------------------+ Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-02-16 09:14:37 +08:00
#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>
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);
fadump: Initialize elfcore header and add PT_LOAD program headers. Build the crash memory range list by traversing through system memory during the first kernel before we register for firmware-assisted dump. After the successful dump registration, initialize the elfcore header and populate PT_LOAD program headers with crash memory ranges. The elfcore header is saved in the scratch area within the reserved memory. The scratch area starts at the end of the memory reserved for saving RMR region contents. The scratch area contains fadump crash info structure that contains magic number for fadump validation and physical address where the eflcore header can be found. This structure will also be used to pass some important crash info data to the second kernel which will help second kernel to populate ELF core header with correct data before it gets exported through /proc/vmcore. Since the firmware preserves the entire partition memory at the time of crash the contents of the scratch area will be preserved till second kernel boot. Since the memory dump exported through /proc/vmcore is in ELF format similar to kdump, it will help us to reuse the kdump infrastructure for dump capture and filtering. Unlike phyp dump, userspace tool does not need to refer any sysfs interface while reading /proc/vmcore. NOTE: The current design implementation does not address a possibility of introducing additional fields (in future) to this structure without affecting compatibility. It's on TODO list to come up with better approach to address this. Reserved dump area start => +-------------------------------------+ | CPU state dump data | +-------------------------------------+ | HPTE region data | +-------------------------------------+ | RMR region data | Scratch area start => +-------------------------------------+ | fadump crash info structure { | | magic nummber | +------|---- elfcorehdr_addr | | | } | +----> +-------------------------------------+ | ELF core header | Reserved dump area end => +-------------------------------------+ Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-02-16 09:14:37 +08:00
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(&sections[1], 2);
break;
case FADUMP_HPTE_REGION:
fw_dump.hpte_region_size =
of_read_ulong(&sections[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;
fadump: Initialize elfcore header and add PT_LOAD program headers. Build the crash memory range list by traversing through system memory during the first kernel before we register for firmware-assisted dump. After the successful dump registration, initialize the elfcore header and populate PT_LOAD program headers with crash memory ranges. The elfcore header is saved in the scratch area within the reserved memory. The scratch area starts at the end of the memory reserved for saving RMR region contents. The scratch area contains fadump crash info structure that contains magic number for fadump validation and physical address where the eflcore header can be found. This structure will also be used to pass some important crash info data to the second kernel which will help second kernel to populate ELF core header with correct data before it gets exported through /proc/vmcore. Since the firmware preserves the entire partition memory at the time of crash the contents of the scratch area will be preserved till second kernel boot. Since the memory dump exported through /proc/vmcore is in ELF format similar to kdump, it will help us to reuse the kdump infrastructure for dump capture and filtering. Unlike phyp dump, userspace tool does not need to refer any sysfs interface while reading /proc/vmcore. NOTE: The current design implementation does not address a possibility of introducing additional fields (in future) to this structure without affecting compatibility. It's on TODO list to come up with better approach to address this. Reserved dump area start => +-------------------------------------+ | CPU state dump data | +-------------------------------------+ | HPTE region data | +-------------------------------------+ | RMR region data | Scratch area start => +-------------------------------------+ | fadump crash info structure { | | magic nummber | +------|---- elfcorehdr_addr | | | } | +----> +-------------------------------------+ | ELF core header | Reserved dump area end => +-------------------------------------+ Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-02-16 09:14:37 +08:00
size += sizeof(struct fadump_crash_info_header);
size += sizeof(struct elfhdr); /* ELF core header.*/
size += sizeof(struct elf_phdr); /* place holder for cpu notes */
fadump: Initialize elfcore header and add PT_LOAD program headers. Build the crash memory range list by traversing through system memory during the first kernel before we register for firmware-assisted dump. After the successful dump registration, initialize the elfcore header and populate PT_LOAD program headers with crash memory ranges. The elfcore header is saved in the scratch area within the reserved memory. The scratch area starts at the end of the memory reserved for saving RMR region contents. The scratch area contains fadump crash info structure that contains magic number for fadump validation and physical address where the eflcore header can be found. This structure will also be used to pass some important crash info data to the second kernel which will help second kernel to populate ELF core header with correct data before it gets exported through /proc/vmcore. Since the firmware preserves the entire partition memory at the time of crash the contents of the scratch area will be preserved till second kernel boot. Since the memory dump exported through /proc/vmcore is in ELF format similar to kdump, it will help us to reuse the kdump infrastructure for dump capture and filtering. Unlike phyp dump, userspace tool does not need to refer any sysfs interface while reading /proc/vmcore. NOTE: The current design implementation does not address a possibility of introducing additional fields (in future) to this structure without affecting compatibility. It's on TODO list to come up with better approach to address this. Reserved dump area start => +-------------------------------------+ | CPU state dump data | +-------------------------------------+ | HPTE region data | +-------------------------------------+ | RMR region data | Scratch area start => +-------------------------------------+ | fadump crash info structure { | | magic nummber | +------|---- elfcorehdr_addr | | | } | +----> +-------------------------------------+ | ELF core header | Reserved dump area end => +-------------------------------------+ Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-02-16 09:14:37 +08:00
/* 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",
(unsigned long long)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));
fadump: Initialize elfcore header and add PT_LOAD program headers. Build the crash memory range list by traversing through system memory during the first kernel before we register for firmware-assisted dump. After the successful dump registration, initialize the elfcore header and populate PT_LOAD program headers with crash memory ranges. The elfcore header is saved in the scratch area within the reserved memory. The scratch area starts at the end of the memory reserved for saving RMR region contents. The scratch area contains fadump crash info structure that contains magic number for fadump validation and physical address where the eflcore header can be found. This structure will also be used to pass some important crash info data to the second kernel which will help second kernel to populate ELF core header with correct data before it gets exported through /proc/vmcore. Since the firmware preserves the entire partition memory at the time of crash the contents of the scratch area will be preserved till second kernel boot. Since the memory dump exported through /proc/vmcore is in ELF format similar to kdump, it will help us to reuse the kdump infrastructure for dump capture and filtering. Unlike phyp dump, userspace tool does not need to refer any sysfs interface while reading /proc/vmcore. NOTE: The current design implementation does not address a possibility of introducing additional fields (in future) to this structure without affecting compatibility. It's on TODO list to come up with better approach to address this. Reserved dump area start => +-------------------------------------+ | CPU state dump data | +-------------------------------------+ | HPTE region data | +-------------------------------------+ | RMR region data | Scratch area start => +-------------------------------------+ | fadump crash info structure { | | magic nummber | +------|---- elfcorehdr_addr | | | } | +----> +-------------------------------------+ | ELF core header | Reserved dump area end => +-------------------------------------+ Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-02-16 09:14:37 +08:00
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, &note, 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, &note, 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, &regs);
SKIP_TO_NEXT_CPU(reg_entry);
} else {
reg_entry++;
reg_entry = fadump_read_registers(reg_entry, &regs);
note_buf = fadump_regs_to_elf_notes(note_buf, &regs);
}
}
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;
}
fadump: Initialize elfcore header and add PT_LOAD program headers. Build the crash memory range list by traversing through system memory during the first kernel before we register for firmware-assisted dump. After the successful dump registration, initialize the elfcore header and populate PT_LOAD program headers with crash memory ranges. The elfcore header is saved in the scratch area within the reserved memory. The scratch area starts at the end of the memory reserved for saving RMR region contents. The scratch area contains fadump crash info structure that contains magic number for fadump validation and physical address where the eflcore header can be found. This structure will also be used to pass some important crash info data to the second kernel which will help second kernel to populate ELF core header with correct data before it gets exported through /proc/vmcore. Since the firmware preserves the entire partition memory at the time of crash the contents of the scratch area will be preserved till second kernel boot. Since the memory dump exported through /proc/vmcore is in ELF format similar to kdump, it will help us to reuse the kdump infrastructure for dump capture and filtering. Unlike phyp dump, userspace tool does not need to refer any sysfs interface while reading /proc/vmcore. NOTE: The current design implementation does not address a possibility of introducing additional fields (in future) to this structure without affecting compatibility. It's on TODO list to come up with better approach to address this. Reserved dump area start => +-------------------------------------+ | CPU state dump data | +-------------------------------------+ | HPTE region data | +-------------------------------------+ | RMR region data | Scratch area start => +-------------------------------------+ | fadump crash info structure { | | magic nummber | +------|---- elfcorehdr_addr | | | } | +----> +-------------------------------------+ | ELF core header | Reserved dump area end => +-------------------------------------+ Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-02-16 09:14:37 +08:00
/*
* 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;
fadump: Initialize elfcore header and add PT_LOAD program headers. Build the crash memory range list by traversing through system memory during the first kernel before we register for firmware-assisted dump. After the successful dump registration, initialize the elfcore header and populate PT_LOAD program headers with crash memory ranges. The elfcore header is saved in the scratch area within the reserved memory. The scratch area starts at the end of the memory reserved for saving RMR region contents. The scratch area contains fadump crash info structure that contains magic number for fadump validation and physical address where the eflcore header can be found. This structure will also be used to pass some important crash info data to the second kernel which will help second kernel to populate ELF core header with correct data before it gets exported through /proc/vmcore. Since the firmware preserves the entire partition memory at the time of crash the contents of the scratch area will be preserved till second kernel boot. Since the memory dump exported through /proc/vmcore is in ELF format similar to kdump, it will help us to reuse the kdump infrastructure for dump capture and filtering. Unlike phyp dump, userspace tool does not need to refer any sysfs interface while reading /proc/vmcore. NOTE: The current design implementation does not address a possibility of introducing additional fields (in future) to this structure without affecting compatibility. It's on TODO list to come up with better approach to address this. Reserved dump area start => +-------------------------------------+ | CPU state dump data | +-------------------------------------+ | HPTE region data | +-------------------------------------+ | RMR region data | Scratch area start => +-------------------------------------+ | fadump crash info structure { | | magic nummber | +------|---- elfcorehdr_addr | | | } | +----> +-------------------------------------+ | ELF core header | Reserved dump area end => +-------------------------------------+ Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-02-16 09:14:37 +08:00
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) ||
fadump: Initialize elfcore header and add PT_LOAD program headers. Build the crash memory range list by traversing through system memory during the first kernel before we register for firmware-assisted dump. After the successful dump registration, initialize the elfcore header and populate PT_LOAD program headers with crash memory ranges. The elfcore header is saved in the scratch area within the reserved memory. The scratch area starts at the end of the memory reserved for saving RMR region contents. The scratch area contains fadump crash info structure that contains magic number for fadump validation and physical address where the eflcore header can be found. This structure will also be used to pass some important crash info data to the second kernel which will help second kernel to populate ELF core header with correct data before it gets exported through /proc/vmcore. Since the firmware preserves the entire partition memory at the time of crash the contents of the scratch area will be preserved till second kernel boot. Since the memory dump exported through /proc/vmcore is in ELF format similar to kdump, it will help us to reuse the kdump infrastructure for dump capture and filtering. Unlike phyp dump, userspace tool does not need to refer any sysfs interface while reading /proc/vmcore. NOTE: The current design implementation does not address a possibility of introducing additional fields (in future) to this structure without affecting compatibility. It's on TODO list to come up with better approach to address this. Reserved dump area start => +-------------------------------------+ | CPU state dump data | +-------------------------------------+ | HPTE region data | +-------------------------------------+ | RMR region data | Scratch area start => +-------------------------------------+ | fadump crash info structure { | | magic nummber | +------|---- elfcorehdr_addr | | | } | +----> +-------------------------------------+ | ELF core header | Reserved dump area end => +-------------------------------------+ Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-02-16 09:14:37 +08:00
(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) {
fadump: Initialize elfcore header and add PT_LOAD program headers. Build the crash memory range list by traversing through system memory during the first kernel before we register for firmware-assisted dump. After the successful dump registration, initialize the elfcore header and populate PT_LOAD program headers with crash memory ranges. The elfcore header is saved in the scratch area within the reserved memory. The scratch area starts at the end of the memory reserved for saving RMR region contents. The scratch area contains fadump crash info structure that contains magic number for fadump validation and physical address where the eflcore header can be found. This structure will also be used to pass some important crash info data to the second kernel which will help second kernel to populate ELF core header with correct data before it gets exported through /proc/vmcore. Since the firmware preserves the entire partition memory at the time of crash the contents of the scratch area will be preserved till second kernel boot. Since the memory dump exported through /proc/vmcore is in ELF format similar to kdump, it will help us to reuse the kdump infrastructure for dump capture and filtering. Unlike phyp dump, userspace tool does not need to refer any sysfs interface while reading /proc/vmcore. NOTE: The current design implementation does not address a possibility of introducing additional fields (in future) to this structure without affecting compatibility. It's on TODO list to come up with better approach to address this. Reserved dump area start => +-------------------------------------+ | CPU state dump data | +-------------------------------------+ | HPTE region data | +-------------------------------------+ | RMR region data | Scratch area start => +-------------------------------------+ | fadump crash info structure { | | magic nummber | +------|---- elfcorehdr_addr | | | } | +----> +-------------------------------------+ | ELF core header | Reserved dump area end => +-------------------------------------+ Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-02-16 09:14:37 +08:00
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;
fadump: Initialize elfcore header and add PT_LOAD program headers. Build the crash memory range list by traversing through system memory during the first kernel before we register for firmware-assisted dump. After the successful dump registration, initialize the elfcore header and populate PT_LOAD program headers with crash memory ranges. The elfcore header is saved in the scratch area within the reserved memory. The scratch area starts at the end of the memory reserved for saving RMR region contents. The scratch area contains fadump crash info structure that contains magic number for fadump validation and physical address where the eflcore header can be found. This structure will also be used to pass some important crash info data to the second kernel which will help second kernel to populate ELF core header with correct data before it gets exported through /proc/vmcore. Since the firmware preserves the entire partition memory at the time of crash the contents of the scratch area will be preserved till second kernel boot. Since the memory dump exported through /proc/vmcore is in ELF format similar to kdump, it will help us to reuse the kdump infrastructure for dump capture and filtering. Unlike phyp dump, userspace tool does not need to refer any sysfs interface while reading /proc/vmcore. NOTE: The current design implementation does not address a possibility of introducing additional fields (in future) to this structure without affecting compatibility. It's on TODO list to come up with better approach to address this. Reserved dump area start => +-------------------------------------+ | CPU state dump data | +-------------------------------------+ | HPTE region data | +-------------------------------------+ | RMR region data | Scratch area start => +-------------------------------------+ | fadump crash info structure { | | magic nummber | +------|---- elfcorehdr_addr | | | } | +----> +-------------------------------------+ | ELF core header | Reserved dump area end => +-------------------------------------+ Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-02-16 09:14:37 +08:00
/*
* 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;
}
fadump: Initialize elfcore header and add PT_LOAD program headers. Build the crash memory range list by traversing through system memory during the first kernel before we register for firmware-assisted dump. After the successful dump registration, initialize the elfcore header and populate PT_LOAD program headers with crash memory ranges. The elfcore header is saved in the scratch area within the reserved memory. The scratch area starts at the end of the memory reserved for saving RMR region contents. The scratch area contains fadump crash info structure that contains magic number for fadump validation and physical address where the eflcore header can be found. This structure will also be used to pass some important crash info data to the second kernel which will help second kernel to populate ELF core header with correct data before it gets exported through /proc/vmcore. Since the firmware preserves the entire partition memory at the time of crash the contents of the scratch area will be preserved till second kernel boot. Since the memory dump exported through /proc/vmcore is in ELF format similar to kdump, it will help us to reuse the kdump infrastructure for dump capture and filtering. Unlike phyp dump, userspace tool does not need to refer any sysfs interface while reading /proc/vmcore. NOTE: The current design implementation does not address a possibility of introducing additional fields (in future) to this structure without affecting compatibility. It's on TODO list to come up with better approach to address this. Reserved dump area start => +-------------------------------------+ | CPU state dump data | +-------------------------------------+ | HPTE region data | +-------------------------------------+ | RMR region data | Scratch area start => +-------------------------------------+ | fadump crash info structure { | | magic nummber | +------|---- elfcorehdr_addr | | | } | +----> +-------------------------------------+ | ELF core header | Reserved dump area end => +-------------------------------------+ Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-02-16 09:14:37 +08:00
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)++;
fadump: Initialize elfcore header and add PT_LOAD program headers. Build the crash memory range list by traversing through system memory during the first kernel before we register for firmware-assisted dump. After the successful dump registration, initialize the elfcore header and populate PT_LOAD program headers with crash memory ranges. The elfcore header is saved in the scratch area within the reserved memory. The scratch area starts at the end of the memory reserved for saving RMR region contents. The scratch area contains fadump crash info structure that contains magic number for fadump validation and physical address where the eflcore header can be found. This structure will also be used to pass some important crash info data to the second kernel which will help second kernel to populate ELF core header with correct data before it gets exported through /proc/vmcore. Since the firmware preserves the entire partition memory at the time of crash the contents of the scratch area will be preserved till second kernel boot. Since the memory dump exported through /proc/vmcore is in ELF format similar to kdump, it will help us to reuse the kdump infrastructure for dump capture and filtering. Unlike phyp dump, userspace tool does not need to refer any sysfs interface while reading /proc/vmcore. NOTE: The current design implementation does not address a possibility of introducing additional fields (in future) to this structure without affecting compatibility. It's on TODO list to come up with better approach to address this. Reserved dump area start => +-------------------------------------+ | CPU state dump data | +-------------------------------------+ | HPTE region data | +-------------------------------------+ | RMR region data | Scratch area start => +-------------------------------------+ | fadump crash info structure { | | magic nummber | +------|---- elfcorehdr_addr | | | } | +----> +-------------------------------------+ | ELF core header | Reserved dump area end => +-------------------------------------+ Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-02-16 09:14:37 +08:00
/* 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;
fadump: Initialize elfcore header and add PT_LOAD program headers. Build the crash memory range list by traversing through system memory during the first kernel before we register for firmware-assisted dump. After the successful dump registration, initialize the elfcore header and populate PT_LOAD program headers with crash memory ranges. The elfcore header is saved in the scratch area within the reserved memory. The scratch area starts at the end of the memory reserved for saving RMR region contents. The scratch area contains fadump crash info structure that contains magic number for fadump validation and physical address where the eflcore header can be found. This structure will also be used to pass some important crash info data to the second kernel which will help second kernel to populate ELF core header with correct data before it gets exported through /proc/vmcore. Since the firmware preserves the entire partition memory at the time of crash the contents of the scratch area will be preserved till second kernel boot. Since the memory dump exported through /proc/vmcore is in ELF format similar to kdump, it will help us to reuse the kdump infrastructure for dump capture and filtering. Unlike phyp dump, userspace tool does not need to refer any sysfs interface while reading /proc/vmcore. NOTE: The current design implementation does not address a possibility of introducing additional fields (in future) to this structure without affecting compatibility. It's on TODO list to come up with better approach to address this. Reserved dump area start => +-------------------------------------+ | CPU state dump data | +-------------------------------------+ | HPTE region data | +-------------------------------------+ | RMR region data | Scratch area start => +-------------------------------------+ | fadump crash info structure { | | magic nummber | +------|---- elfcorehdr_addr | | | } | +----> +-------------------------------------+ | ELF core header | Reserved dump area end => +-------------------------------------+ Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-02-16 09:14:37 +08:00
return addr;
}
static void register_fadump(void)
{
fadump: Initialize elfcore header and add PT_LOAD program headers. Build the crash memory range list by traversing through system memory during the first kernel before we register for firmware-assisted dump. After the successful dump registration, initialize the elfcore header and populate PT_LOAD program headers with crash memory ranges. The elfcore header is saved in the scratch area within the reserved memory. The scratch area starts at the end of the memory reserved for saving RMR region contents. The scratch area contains fadump crash info structure that contains magic number for fadump validation and physical address where the eflcore header can be found. This structure will also be used to pass some important crash info data to the second kernel which will help second kernel to populate ELF core header with correct data before it gets exported through /proc/vmcore. Since the firmware preserves the entire partition memory at the time of crash the contents of the scratch area will be preserved till second kernel boot. Since the memory dump exported through /proc/vmcore is in ELF format similar to kdump, it will help us to reuse the kdump infrastructure for dump capture and filtering. Unlike phyp dump, userspace tool does not need to refer any sysfs interface while reading /proc/vmcore. NOTE: The current design implementation does not address a possibility of introducing additional fields (in future) to this structure without affecting compatibility. It's on TODO list to come up with better approach to address this. Reserved dump area start => +-------------------------------------+ | CPU state dump data | +-------------------------------------+ | HPTE region data | +-------------------------------------+ | RMR region data | Scratch area start => +-------------------------------------+ | fadump crash info structure { | | magic nummber | +------|---- elfcorehdr_addr | | | } | +----> +-------------------------------------+ | ELF core header | Reserved dump area end => +-------------------------------------+ Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-02-16 09:14:37 +08:00
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: Initialize elfcore header and add PT_LOAD program headers. Build the crash memory range list by traversing through system memory during the first kernel before we register for firmware-assisted dump. After the successful dump registration, initialize the elfcore header and populate PT_LOAD program headers with crash memory ranges. The elfcore header is saved in the scratch area within the reserved memory. The scratch area starts at the end of the memory reserved for saving RMR region contents. The scratch area contains fadump crash info structure that contains magic number for fadump validation and physical address where the eflcore header can be found. This structure will also be used to pass some important crash info data to the second kernel which will help second kernel to populate ELF core header with correct data before it gets exported through /proc/vmcore. Since the firmware preserves the entire partition memory at the time of crash the contents of the scratch area will be preserved till second kernel boot. Since the memory dump exported through /proc/vmcore is in ELF format similar to kdump, it will help us to reuse the kdump infrastructure for dump capture and filtering. Unlike phyp dump, userspace tool does not need to refer any sysfs interface while reading /proc/vmcore. NOTE: The current design implementation does not address a possibility of introducing additional fields (in future) to this structure without affecting compatibility. It's on TODO list to come up with better approach to address this. Reserved dump area start => +-------------------------------------+ | CPU state dump data | +-------------------------------------+ | HPTE region data | +-------------------------------------+ | RMR region data | Scratch area start => +-------------------------------------+ | fadump crash info structure { | | magic nummber | +------|---- elfcorehdr_addr | | | } | +----> +-------------------------------------+ | ELF core header | Reserved dump area end => +-------------------------------------+ Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-02-16 09:14:37 +08:00
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;
ClearPageReserved(pfn_to_page(addr >> PAGE_SHIFT));
init_page_count(pfn_to_page(addr >> PAGE_SHIFT));
free_page((unsigned long)__va(addr));
totalram_pages++;
}
}
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();
fadump: Initialize elfcore header and add PT_LOAD program headers. Build the crash memory range list by traversing through system memory during the first kernel before we register for firmware-assisted dump. After the successful dump registration, initialize the elfcore header and populate PT_LOAD program headers with crash memory ranges. The elfcore header is saved in the scratch area within the reserved memory. The scratch area starts at the end of the memory reserved for saving RMR region contents. The scratch area contains fadump crash info structure that contains magic number for fadump validation and physical address where the eflcore header can be found. This structure will also be used to pass some important crash info data to the second kernel which will help second kernel to populate ELF core header with correct data before it gets exported through /proc/vmcore. Since the firmware preserves the entire partition memory at the time of crash the contents of the scratch area will be preserved till second kernel boot. Since the memory dump exported through /proc/vmcore is in ELF format similar to kdump, it will help us to reuse the kdump infrastructure for dump capture and filtering. Unlike phyp dump, userspace tool does not need to refer any sysfs interface while reading /proc/vmcore. NOTE: The current design implementation does not address a possibility of introducing additional fields (in future) to this structure without affecting compatibility. It's on TODO list to come up with better approach to address this. Reserved dump area start => +-------------------------------------+ | CPU state dump data | +-------------------------------------+ | HPTE region data | +-------------------------------------+ | RMR region data | Scratch area start => +-------------------------------------+ | fadump crash info structure { | | magic nummber | +------|---- elfcorehdr_addr | | | } | +----> +-------------------------------------+ | ELF core header | Reserved dump area end => +-------------------------------------+ Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-02-16 09:14:37 +08:00
/*
* 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. */
fadump: Initialize elfcore header and add PT_LOAD program headers. Build the crash memory range list by traversing through system memory during the first kernel before we register for firmware-assisted dump. After the successful dump registration, initialize the elfcore header and populate PT_LOAD program headers with crash memory ranges. The elfcore header is saved in the scratch area within the reserved memory. The scratch area starts at the end of the memory reserved for saving RMR region contents. The scratch area contains fadump crash info structure that contains magic number for fadump validation and physical address where the eflcore header can be found. This structure will also be used to pass some important crash info data to the second kernel which will help second kernel to populate ELF core header with correct data before it gets exported through /proc/vmcore. Since the firmware preserves the entire partition memory at the time of crash the contents of the scratch area will be preserved till second kernel boot. Since the memory dump exported through /proc/vmcore is in ELF format similar to kdump, it will help us to reuse the kdump infrastructure for dump capture and filtering. Unlike phyp dump, userspace tool does not need to refer any sysfs interface while reading /proc/vmcore. NOTE: The current design implementation does not address a possibility of introducing additional fields (in future) to this structure without affecting compatibility. It's on TODO list to come up with better approach to address this. Reserved dump area start => +-------------------------------------+ | CPU state dump data | +-------------------------------------+ | HPTE region data | +-------------------------------------+ | RMR region data | Scratch area start => +-------------------------------------+ | fadump crash info structure { | | magic nummber | +------|---- elfcorehdr_addr | | | } | +----> +-------------------------------------+ | ELF core header | Reserved dump area end => +-------------------------------------+ Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-02-16 09:14:37 +08:00
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);