From eb39c8803d0e3d98fe74825f99287f63d55e6460 Mon Sep 17 00:00:00 2001 From: Mahesh Salgaonkar Date: Thu, 16 Feb 2012 01:14:22 +0000 Subject: fadump: Reserve the memory for firmware assisted dump. Reserve the memory during early boot to preserve CPU state data, HPTE region and RMA (real mode area) region data in case of kernel crash. At the time of crash, powerpc firmware will store CPU state data, HPTE region data and move RMA region data to the reserved memory area. If the firmware-assisted dump fails to reserve the memory, then fallback to existing kexec-based kdump. Most of the code implementation to reserve memory has been adapted from phyp assisted dump implementation written by Linas Vepstas and Manish Ahuja This patch also introduces a config option CONFIG_FA_DUMP for firmware assisted dump feature on Powerpc (ppc64) architecture. Signed-off-by: Mahesh Salgaonkar Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/kernel/fadump.c | 246 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 246 insertions(+) create mode 100644 arch/powerpc/kernel/fadump.c (limited to 'arch/powerpc/kernel/fadump.c') diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c new file mode 100644 index 000000000000..deb276a9ce71 --- /dev/null +++ b/arch/powerpc/kernel/fadump.c @@ -0,0 +1,246 @@ +/* + * 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 + */ + +#undef DEBUG +#define pr_fmt(fmt) "fadump: " fmt + +#include +#include + +#include +#include +#include +#include + +static struct fw_dump fw_dump; + +/* 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. + */ + if (of_get_flat_dt_prop(node, "ibm,kernel-dump", NULL)) + 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; +} + +/** + * 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 = 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 */ + 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)); + } 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); -- cgit v1.2.2 From 3ccc00a7e04ff7718c9aebb4b0c982571c798759 Mon Sep 17 00:00:00 2001 From: Mahesh Salgaonkar Date: Mon, 20 Feb 2012 02:15:03 +0000 Subject: fadump: Register for firmware assisted dump. On 2012-02-20 11:02:51 Mon, Paul Mackerras wrote: > On Thu, Feb 16, 2012 at 04:44:30PM +0530, Mahesh J Salgaonkar wrote: > > If I have read the code correctly, we are going to get this printk on > non-pSeries machines or on older pSeries machines, even if the user > has not put the fadump=on option on the kernel command line. The > printk will be annoying since there is no actual error condition. It > seems to me that the condition for the printk should include > fw_dump.fadump_enabled. In other words you should probably add > > if (!fw_dump.fadump_enabled) > return 0; > > at the beginning of the function. Hi Paul, Thanks for pointing it out. Please find the updated patch below. The existing patches above this (4/10 through 10/10) cleanly applies on this update. Thanks, -Mahesh. Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/kernel/fadump.c | 355 ++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 352 insertions(+), 3 deletions(-) (limited to 'arch/powerpc/kernel/fadump.c') diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c index deb276a9ce71..eb8f782afade 100644 --- a/arch/powerpc/kernel/fadump.c +++ b/arch/powerpc/kernel/fadump.c @@ -29,6 +29,9 @@ #include #include +#include +#include +#include #include #include @@ -36,6 +39,10 @@ #include 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); /* Scan the Firmware Assisted dump configuration details. */ int __init early_init_dt_scan_fw_dump(unsigned long node, @@ -64,7 +71,8 @@ int __init early_init_dt_scan_fw_dump(unsigned long node, * The 'ibm,kernel-dump' rtas node is present only if there is * dump data waiting for us. */ - if (of_get_flat_dt_prop(node, "ibm,kernel-dump", NULL)) + 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 @@ -98,6 +106,85 @@ int __init early_init_dt_scan_fw_dump(unsigned long node, 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 * @@ -166,8 +253,15 @@ int __init fadump_reserve_mem(void) fw_dump.fadump_enabled = 0; return 0; } - /* Initialize boot memory size */ - fw_dump.boot_memory_size = fadump_calculate_reserve_size(); + /* + * 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. @@ -244,3 +338,258 @@ static int __init early_fadump_reserve_mem(char *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; + } +} + +static void register_fadump(void) +{ + /* + * If no memory is reserved then we can not register for firmware- + * assisted dump. + */ + if (!fw_dump.reserve_dump_area_size) + return; + + /* 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 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; + + if (fdm_active) + fdm_ptr = fdm_active; + else + 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)) + return 0; + + /* 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); + return 0; +} + +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"); + 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(); + /* Initialize the kernel dump memory structure for FAD registration. */ + 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); -- cgit v1.2.2 From 2df173d9e85d9e2c6a8933c63f0c034accff7e0f Mon Sep 17 00:00:00 2001 From: Mahesh Salgaonkar Date: Thu, 16 Feb 2012 01:14:37 +0000 Subject: 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 Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/kernel/fadump.c | 233 ++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 232 insertions(+), 1 deletion(-) (limited to 'arch/powerpc/kernel/fadump.c') diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c index eb8f782afade..63857e183de5 100644 --- a/arch/powerpc/kernel/fadump.c +++ b/arch/powerpc/kernel/fadump.c @@ -32,6 +32,7 @@ #include #include #include +#include #include #include @@ -43,6 +44,8 @@ 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, @@ -235,6 +238,10 @@ static unsigned long get_fadump_area_size(void) 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.*/ + /* Program headers for crash memory regions. */ + size += sizeof(struct elf_phdr) * (memblock_num_regions(memory) + 2); size = PAGE_ALIGN(size); return size; @@ -300,6 +307,12 @@ int __init fadump_reserve_mem(void) "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(); @@ -380,8 +393,210 @@ static void register_fw_dump(struct fadump_mem_struct *fdm) } } +/* + * 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; + + 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->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) { + 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; + } + + /* + * 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); + } +} + +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 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; + + 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. @@ -389,6 +604,16 @@ static void register_fadump(void) 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); } @@ -585,8 +810,14 @@ int __init setup_fadump(void) } 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) + process_fadump(fdm_active); /* Initialize the kernel dump memory structure for FAD registration. */ - if (fw_dump.reserve_dump_area_size) + else if (fw_dump.reserve_dump_area_size) init_fadump_mem_struct(&fdm, fw_dump.reserve_dump_area_start); fadump_init_files(); -- cgit v1.2.2 From ebaeb5ae24379b5b635dc1d1fa6df904bc95b4d9 Mon Sep 17 00:00:00 2001 From: Mahesh Salgaonkar Date: Thu, 16 Feb 2012 01:14:45 +0000 Subject: fadump: Convert firmware-assisted cpu state dump data into elf notes. When registered for firmware assisted dump on powerpc, firmware preserves the registers for the active CPUs during a system crash. This patch reads the cpu register data stored in Firmware-assisted dump format (except for crashing cpu) and converts it into elf notes and updates the PT_NOTE program header accordingly. The exact register state for crashing cpu is saved to fadump crash info structure in scratch area during crash_fadump() and read during second kernel boot. Signed-off-by: Mahesh Salgaonkar Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/kernel/fadump.c | 314 ++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 312 insertions(+), 2 deletions(-) (limited to 'arch/powerpc/kernel/fadump.c') diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c index 63857e183de5..da68bdad194a 100644 --- a/arch/powerpc/kernel/fadump.c +++ b/arch/powerpc/kernel/fadump.c @@ -240,6 +240,7 @@ static unsigned long get_fadump_area_size(void) 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); @@ -393,6 +394,285 @@ static void register_fw_dump(struct fadump_mem_struct *fdm) } } +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'. @@ -400,18 +680,21 @@ static void register_fw_dump(struct fadump_mem_struct *fdm) 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) { + 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; } @@ -423,6 +706,10 @@ static int __init process_fadump(const struct fadump_mem_struct *fdm_active) 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 @@ -537,6 +824,27 @@ static int fadump_create_elfcore_headers(char *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 PT_LOAD sections. */ for (i = 0; i < crash_mem_ranges; i++) { @@ -588,6 +896,8 @@ static unsigned long init_fadump_header(unsigned long addr) 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; } -- cgit v1.2.2 From d34c5f26cf7de52a72ee064698817a5a39b91767 Mon Sep 17 00:00:00 2001 From: Mahesh Salgaonkar Date: Thu, 16 Feb 2012 01:14:53 +0000 Subject: fadump: Add PT_NOTE program header for vmcoreinfo Introduce a PT_NOTE program header that points to physical address of vmcoreinfo_note buffer declared in kernel/kexec.c. The vmcoreinfo note buffer is populated during crash_fadump() at the time of system crash. Signed-off-by: Mahesh Salgaonkar Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/kernel/fadump.c | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+) (limited to 'arch/powerpc/kernel/fadump.c') diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c index da68bdad194a..a83bc9015c64 100644 --- a/arch/powerpc/kernel/fadump.c +++ b/arch/powerpc/kernel/fadump.c @@ -814,6 +814,19 @@ static void fadump_setup_crash_memory_ranges(void) } } +/* + * 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; @@ -845,6 +858,22 @@ static int fadump_create_elfcore_headers(char *bufp) (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++) { -- cgit v1.2.2 From b500afff11f64227ca69fd2d05986d08d9573935 Mon Sep 17 00:00:00 2001 From: Mahesh Salgaonkar Date: Thu, 16 Feb 2012 01:15:08 +0000 Subject: fadump: Invalidate registration and release reserved memory for general use. This patch introduces an sysfs interface '/sys/kernel/fadump_release_mem' to invalidate the last fadump registration, invalidate '/proc/vmcore', release the reserved memory for general use and re-register for future kernel dump. Once the dump is copied to the disk, unlike phyp dump, the userspace tool can release all the memory reserved for dump with one single operation of echo 1 to '/sys/kernel/fadump_release_mem'. Release the reserved memory region excluding the size of the memory required for future kernel dump registration. And therefore, unlike kdump, Fadump doesn't need a 2nd reboot to get back the system to the production configuration. Signed-off-by: Mahesh Salgaonkar Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/kernel/fadump.c | 158 +++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 154 insertions(+), 4 deletions(-) (limited to 'arch/powerpc/kernel/fadump.c') diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c index a83bc9015c64..cfe7a38708c3 100644 --- a/arch/powerpc/kernel/fadump.c +++ b/arch/powerpc/kernel/fadump.c @@ -33,6 +33,8 @@ #include #include #include +#include +#include #include #include @@ -984,6 +986,132 @@ static int fadump_unregister_dump(struct fadump_mem_struct *fdm) 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) @@ -1043,10 +1171,13 @@ static int fadump_region_show(struct seq_file *m, void *private) if (!fw_dump.fadump_enabled) return 0; + mutex_lock(&fadump_mutex); if (fdm_active) fdm_ptr = fdm_active; - else + else { + mutex_unlock(&fadump_mutex); fdm_ptr = &fdm; + } seq_printf(m, "CPU : [%#016llx-%#016llx] %#llx bytes, " @@ -1076,7 +1207,7 @@ static int fadump_region_show(struct seq_file *m, void *private) if (!fdm_active || (fw_dump.reserve_dump_area_start == fdm_ptr->cpu_state_data.destination_address)) - return 0; + goto out; /* Dump is active. Show reserved memory region. */ seq_printf(m, @@ -1088,9 +1219,15 @@ static int fadump_region_show(struct seq_file *m, void *private) 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); @@ -1131,6 +1268,13 @@ static void fadump_init_files(void) 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; } @@ -1153,8 +1297,14 @@ int __init setup_fadump(void) * If dump data is available then see if it is valid and prepare for * saving it to the disk. */ - if (fw_dump.dump_active) - process_fadump(fdm_active); + 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); -- cgit v1.2.2