// SPDX-License-Identifier: GPL-2.0-or-later /* * 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 * * Copyright 2011 IBM Corporation * Author: Mahesh Salgaonkar */ #undef DEBUG #define pr_fmt(fmt) "fadump: " fmt #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include static struct fw_dump fw_dump; static struct fadump_mem_struct fdm; static const struct fadump_mem_struct *fdm_active; #ifdef CONFIG_CMA static struct cma *fadump_cma; #endif static DEFINE_MUTEX(fadump_mutex); struct fad_crash_memory_ranges *crash_memory_ranges; int crash_memory_ranges_size; int crash_mem_ranges; int max_crash_mem_ranges; #ifdef CONFIG_CMA /* * fadump_cma_init() - Initialize CMA area from a fadump reserved memory * * This function initializes CMA area from fadump reserved memory. * The total size of fadump reserved memory covers for boot memory size * + cpu data size + hpte size and metadata. * Initialize only the area equivalent to boot memory size for CMA use. * The reamining portion of fadump reserved memory will be not given * to CMA and pages for thoes will stay reserved. boot memory size is * aligned per CMA requirement to satisy cma_init_reserved_mem() call. * But for some reason even if it fails we still have the memory reservation * with us and we can still continue doing fadump. */ int __init fadump_cma_init(void) { unsigned long long base, size; int rc; if (!fw_dump.fadump_enabled) return 0; /* * Do not use CMA if user has provided fadump=nocma kernel parameter. * Return 1 to continue with fadump old behaviour. */ if (fw_dump.nocma) return 1; base = fw_dump.reserve_dump_area_start; size = fw_dump.boot_memory_size; if (!size) return 0; rc = cma_init_reserved_mem(base, size, 0, "fadump_cma", &fadump_cma); if (rc) { pr_err("Failed to init cma area for firmware-assisted dump,%d\n", rc); /* * Though the CMA init has failed we still have memory * reservation with us. The reserved memory will be * blocked from production system usage. Hence return 1, * so that we can continue with fadump. */ return 1; } /* * So we now have successfully initialized cma area for fadump. */ pr_info("Initialized 0x%lx bytes cma area at %ldMB from 0x%lx " "bytes of memory reserved for firmware-assisted dump\n", cma_get_size(fadump_cma), (unsigned long)cma_get_base(fadump_cma) >> 20, fw_dump.reserve_dump_area_size); return 1; } #else static int __init fadump_cma_init(void) { return 1; } #endif /* CONFIG_CMA */ /* 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) { const __be32 *sections; int i, num_sections; int size; const __be32 *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 1; fw_dump.fadump_supported = 1; fw_dump.ibm_configure_kernel_dump = be32_to_cpu(*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 1; 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; } /* * If fadump is registered, check if the memory provided * falls within boot memory area and reserved memory area. */ int is_fadump_memory_area(u64 addr, ulong size) { u64 d_start = fw_dump.reserve_dump_area_start; u64 d_end = d_start + fw_dump.reserve_dump_area_size; if (!fw_dump.dump_registered) return 0; if (((addr + size) > d_start) && (addr <= d_end)) return 1; return (addr + size) > RMA_START && addr <= fw_dump.boot_memory_size; } int should_fadump_crash(void) { if (!fw_dump.dump_registered || !fw_dump.fadumphdr_addr) return 0; return 1; } int is_fadump_active(void) { return fw_dump.dump_active; } /* * Returns 1, if there are no holes in boot memory area, * 0 otherwise. */ static int is_boot_memory_area_contiguous(void) { struct memblock_region *reg; unsigned long tstart, tend; unsigned long start_pfn = PHYS_PFN(RMA_START); unsigned long end_pfn = PHYS_PFN(RMA_START + fw_dump.boot_memory_size); unsigned int ret = 0; for_each_memblock(memory, reg) { tstart = max(start_pfn, memblock_region_memory_base_pfn(reg)); tend = min(end_pfn, memblock_region_memory_end_pfn(reg)); if (tstart < tend) { /* Memory hole from start_pfn to tstart */ if (tstart > start_pfn) break; if (tend == end_pfn) { ret = 1; break; } start_pfn = tend + 1; } } return ret; } /* * Returns true, if there are no holes in reserved memory area, * false otherwise. */ static bool is_reserved_memory_area_contiguous(void) { struct memblock_region *reg; unsigned long start, end; unsigned long d_start = fw_dump.reserve_dump_area_start; unsigned long d_end = d_start + fw_dump.reserve_dump_area_size; for_each_memblock(memory, reg) { start = max(d_start, (unsigned long)reg->base); end = min(d_end, (unsigned long)(reg->base + reg->size)); if (d_start < end) { /* Memory hole from d_start to start */ if (start > d_start) break; if (end == d_end) return true; d_start = end + 1; } } return false; } /* 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 = cpu_to_be32(0x00000001); fdm->header.dump_num_sections = cpu_to_be16(3); fdm->header.dump_status_flag = 0; fdm->header.offset_first_dump_section = cpu_to_be32((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 = cpu_to_be32(FADUMP_REQUEST_FLAG); fdm->cpu_state_data.source_data_type = cpu_to_be16(FADUMP_CPU_STATE_DATA); fdm->cpu_state_data.source_address = 0; fdm->cpu_state_data.source_len = cpu_to_be64(fw_dump.cpu_state_data_size); fdm->cpu_state_data.destination_address = cpu_to_be64(addr); addr += fw_dump.cpu_state_data_size; /* hpte region section */ fdm->hpte_region.request_flag = cpu_to_be32(FADUMP_REQUEST_FLAG); fdm->hpte_region.source_data_type = cpu_to_be16(FADUMP_HPTE_REGION); fdm->hpte_region.source_address = 0; fdm->hpte_region.source_len = cpu_to_be64(fw_dump.hpte_region_size); fdm->hpte_region.destination_address = cpu_to_be64(addr); addr += fw_dump.hpte_region_size; /* RMA region section */ fdm->rmr_region.request_flag = cpu_to_be32(FADUMP_REQUEST_FLAG); fdm->rmr_region.source_data_type = cpu_to_be16(FADUMP_REAL_MODE_REGION); fdm->rmr_region.source_address = cpu_to_be64(RMA_START); fdm->rmr_region.source_len = cpu_to_be64(fw_dump.boot_memory_size); fdm->rmr_region.destination_address = cpu_to_be64(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) { int ret; unsigned long long base, size; if (fw_dump.reserve_bootvar) pr_warn("'fadump_reserve_mem=' parameter is deprecated in favor of 'crashkernel=' parameter.\n"); /* * Check if the size is specified through crashkernel= cmdline * option. If yes, then use that but ignore base as fadump reserves * memory at a predefined offset. */ ret = parse_crashkernel(boot_command_line, memblock_phys_mem_size(), &size, &base); if (ret == 0 && size > 0) { unsigned long max_size; if (fw_dump.reserve_bootvar) pr_info("Using 'crashkernel=' parameter for memory reservation.\n"); fw_dump.reserve_bootvar = (unsigned long)size; /* * Adjust if the boot memory size specified is above * the upper limit. */ max_size = memblock_phys_mem_size() / MAX_BOOT_MEM_RATIO; if (fw_dump.reserve_bootvar > max_size) { fw_dump.reserve_bootvar = max_size; pr_info("Adjusted boot memory size to %luMB\n", (fw_dump.reserve_bootvar >> 20)); } return fw_dump.reserve_bootvar; } else if (fw_dump.reserve_bootvar) { /* * 'fadump_reserve_mem=' is being used to reserve memory * for firmware-assisted dump. */ return fw_dump.reserve_bootvar; } /* divide by 20 to get 5% of value */ size = memblock_phys_mem_size() / 20; /* round it down in multiples of 256 */ size = size & ~0x0FFFFFFFUL; /* Truncate to memory_limit. We don't want to over reserve the memory.*/ if (memory_limit && size > memory_limit) size = memory_limit; return (size > MIN_BOOT_MEM ? size : MIN_BOOT_MEM); } /* * Calculate the total memory size required to be reserved for * firmware-assisted dump registration. */ static unsigned long get_fadump_area_size(void) { unsigned long size = 0; size += fw_dump.cpu_state_data_size; size += fw_dump.hpte_region_size; size += fw_dump.boot_memory_size; size += sizeof(struct fadump_crash_info_header); size += sizeof(struct elfhdr); /* ELF core header.*/ size += sizeof(struct elf_phdr); /* place holder for cpu notes */ /* Program headers for crash memory regions. */ size += sizeof(struct elf_phdr) * (memblock_num_regions(memory) + 2); size = PAGE_ALIGN(size); return size; } static void __init fadump_reserve_crash_area(unsigned long base, unsigned long size) { struct memblock_region *reg; unsigned long mstart, mend, msize; for_each_memblock(memory, reg) { mstart = max_t(unsigned long, base, reg->base); mend = reg->base + reg->size; mend = min(base + size, mend); if (mstart < mend) { msize = mend - mstart; memblock_reserve(mstart, msize); pr_info("Reserved %ldMB of memory at %#016lx for saving crash dump\n", (msize >> 20), mstart); } } } 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 = be64_to_cpu(fdm_active->rmr_region.source_len); else { fw_dump.boot_memory_size = fadump_calculate_reserve_size(); #ifdef CONFIG_CMA if (!fw_dump.nocma) fw_dump.boot_memory_size = ALIGN(fw_dump.boot_memory_size, FADUMP_CMA_ALIGNMENT); #endif } /* * Calculate the memory boundary. * If memory_limit is less than actual memory boundary then reserve * the memory for fadump beyond the memory_limit and adjust the * memory_limit accordingly, so that the running kernel can run with * specified memory_limit. */ if (memory_limit && memory_limit < memblock_end_of_DRAM()) { size = get_fadump_area_size(); if ((memory_limit + size) < memblock_end_of_DRAM()) memory_limit += size; else memory_limit = memblock_end_of_DRAM(); printk(KERN_INFO "Adjusted memory_limit for firmware-assisted" " dump, now %#016llx\n", memory_limit); } if (memory_limit) memory_boundary = memory_limit; else memory_boundary = memblock_end_of_DRAM(); if (fw_dump.dump_active) { pr_info("Firmware-assisted dump is active.\n"); #ifdef CONFIG_HUGETLB_PAGE /* * FADump capture kernel doesn't care much about hugepages. * In fact, handling hugepages in capture kernel is asking for * trouble. So, disable HugeTLB support when fadump is active. */ hugetlb_disabled = true; #endif /* * 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; fadump_reserve_crash_area(base, size); fw_dump.fadumphdr_addr = be64_to_cpu(fdm_active->rmr_region.destination_address) + be64_to_cpu(fdm_active->rmr_region.source_len); pr_debug("fadumphdr_addr = %pa\n", &fw_dump.fadumphdr_addr); fw_dump.reserve_dump_area_start = base; fw_dump.reserve_dump_area_size = size; } else { size = get_fadump_area_size(); /* * Reserve memory at an offset closer to bottom of the RAM to * minimize the impact of memory hot-remove operation. We can't * use memblock_find_in_range() here since it doesn't allocate * from bottom to top. */ for (base = fw_dump.boot_memory_size; base <= (memory_boundary - size); base += size) { if (memblock_is_region_memory(base, size) && !memblock_is_region_reserved(base, size)) break; } if ((base > (memory_boundary - size)) || memblock_reserve(base, size)) { pr_err("Failed to reserve memory\n"); return 0; } pr_info("Reserved %ldMB of memory at %ldMB for firmware-" "assisted dump (System RAM: %ldMB)\n", (unsigned long)(size >> 20), (unsigned long)(base >> 20), (unsigned long)(memblock_phys_mem_size() >> 20)); fw_dump.reserve_dump_area_start = base; fw_dump.reserve_dump_area_size = size; return fadump_cma_init(); } return 1; } unsigned long __init arch_reserved_kernel_pages(void) { return memblock_reserved_size() / PAGE_SIZE; } /* 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; else if (strncmp(p, "nocma", 5) == 0) { fw_dump.fadump_enabled = 1; fw_dump.nocma = 1; } return 0; } early_param("fadump", early_fadump_param); /* * Look for fadump_reserve_mem= cmdline option * TODO: Remove references to 'fadump_reserve_mem=' parameter, * the sooner 'crashkernel=' parameter is accustomed to. */ 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 int register_fw_dump(struct fadump_mem_struct *fdm) { int rc, err; 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); err = -EIO; switch (rc) { default: pr_err("Failed to register. Unknown Error(%d).\n", rc); break; case -1: printk(KERN_ERR "Failed to register firmware-assisted kernel" " dump. Hardware Error(%d).\n", rc); break; case -3: if (!is_boot_memory_area_contiguous()) pr_err("Can't have holes in boot memory area while registering fadump\n"); else if (!is_reserved_memory_area_contiguous()) pr_err("Can't have holes in reserved memory area while" " registering fadump\n"); printk(KERN_ERR "Failed to register firmware-assisted kernel" " dump. Parameter Error(%d).\n", rc); err = -EINVAL; break; case -9: printk(KERN_ERR "firmware-assisted kernel dump is already " " registered."); fw_dump.dump_registered = 1; err = -EEXIST; break; case 0: printk(KERN_INFO "firmware-assisted kernel dump registration" " is successful\n"); fw_dump.dump_registered = 1; err = 0; break; } return err; } void crash_fadump(struct pt_regs *regs, const char *str) { struct fadump_crash_info_header *fdh = NULL; int old_cpu, this_cpu; if (!should_fadump_crash()) return; /* * old_cpu == -1 means this is the first CPU which has come here, * go ahead and trigger fadump. * * old_cpu != -1 means some other CPU has already on it's way * to trigger fadump, just keep looping here. */ this_cpu = smp_processor_id(); old_cpu = cmpxchg(&crashing_cpu, -1, this_cpu); if (old_cpu != -1) { /* * We can't loop here indefinitely. Wait as long as fadump * is in force. If we race with fadump un-registration this * loop will break and then we go down to normal panic path * and reboot. If fadump is in force the first crashing * cpu will definitely trigger fadump. */ while (fw_dump.dump_registered) cpu_relax(); return; } fdh = __va(fw_dump.fadumphdr_addr); fdh->crashing_cpu = crashing_cpu; crash_save_vmcoreinfo(); if (regs) fdh->regs = *regs; else ppc_save_regs(&fdh->regs); fdh->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 (be64_to_cpu(reg_entry->reg_id) != REG_ID("CPUEND")) { fadump_set_regval(regs, be64_to_cpu(reg_entry->reg_id), be64_to_cpu(reg_entry->reg_value)); reg_entry++; } reg_entry++; return reg_entry; } 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 = append_elf_note(buf, CRASH_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 = be64_to_cpu(fdm->cpu_state_data.destination_address); vaddr = __va(addr); reg_header = vaddr; if (be64_to_cpu(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", be64_to_cpu(reg_header->magic_number)); pr_debug("NumCpuOffset: %x\n", be32_to_cpu(reg_header->num_cpu_offset)); vaddr += be32_to_cpu(reg_header->num_cpu_offset); num_cpus = be32_to_cpu(*((__be32 *)(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 (be64_to_cpu(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 = be64_to_cpu(reg_entry->reg_value) & FADUMP_CPU_ID_MASK; if (fdh && !cpumask_test_cpu(cpu, &fdh->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); } } final_note(note_buf); if (fdh) { pr_debug("Updating elfcore header (%llx) with cpu notes\n", fdh->elfcorehdr_addr); fadump_update_elfcore_header((char *)__va(fdh->elfcorehdr_addr)); } return 0; error_out: fadump_cpu_notes_buf_free((unsigned long)__va(fw_dump.cpu_notes_buf), fw_dump.cpu_notes_buf_size); fw_dump.cpu_notes_buf = 0; fw_dump.cpu_notes_buf_size = 0; return rc; } /* * Validate and process the dump data stored by firmware before exporting * it through '/proc/vmcore'. */ static int __init process_fadump(const struct fadump_mem_struct *fdm_active) { struct fadump_crash_info_header *fdh; int rc = 0; if (!fdm_active || !fw_dump.fadumphdr_addr) return -EINVAL; /* Check if the dump data is valid. */ if ((be16_to_cpu(fdm_active->header.dump_status_flag) == FADUMP_ERROR_FLAG) || (fdm_active->cpu_state_data.error_flags != 0) || (fdm_active->rmr_region.error_flags != 0)) { printk(KERN_ERR "Dump taken by platform is not valid\n"); return -EINVAL; } if ((fdm_active->rmr_region.bytes_dumped != fdm_active->rmr_region.source_len) || !fdm_active->cpu_state_data.bytes_dumped) { printk(KERN_ERR "Dump taken by platform is incomplete\n"); return -EINVAL; } /* Validate the fadump crash info header */ fdh = __va(fw_dump.fadumphdr_addr); if (fdh->magic_number != FADUMP_CRASH_INFO_MAGIC) { printk(KERN_ERR "Crash info header is not valid.\n"); return -EINVAL; } rc = fadump_build_cpu_notes(fdm_active); if (rc) return rc; /* * We are done validating dump info and elfcore header is now ready * to be exported. set elfcorehdr_addr so that vmcore module will * export the elfcore header through '/proc/vmcore'. */ elfcorehdr_addr = fdh->elfcorehdr_addr; return 0; } static void free_crash_memory_ranges(void) { kfree(crash_memory_ranges); crash_memory_ranges = NULL; crash_memory_ranges_size = 0; max_crash_mem_ranges = 0; } /* * Allocate or reallocate crash memory ranges array in incremental units * of PAGE_SIZE. */ static int allocate_crash_memory_ranges(void) { struct fad_crash_memory_ranges *new_array; u64 new_size; new_size = crash_memory_ranges_size + PAGE_SIZE; pr_debug("Allocating %llu bytes of memory for crash memory ranges\n", new_size); new_array = krealloc(crash_memory_ranges, new_size, GFP_KERNEL); if (new_array == NULL) { pr_err("Insufficient memory for setting up crash memory ranges\n"); free_crash_memory_ranges(); return -ENOMEM; } crash_memory_ranges = new_array; crash_memory_ranges_size = new_size; max_crash_mem_ranges = (new_size / sizeof(struct fad_crash_memory_ranges)); return 0; } static inline int fadump_add_crash_memory(unsigned long long base, unsigned long long end) { u64 start, size; bool is_adjacent = false; if (base == end) return 0; /* * Fold adjacent memory ranges to bring down the memory ranges/ * PT_LOAD segments count. */ if (crash_mem_ranges) { start = crash_memory_ranges[crash_mem_ranges - 1].base; size = crash_memory_ranges[crash_mem_ranges - 1].size; if ((start + size) == base) is_adjacent = true; } if (!is_adjacent) { /* resize the array on reaching the limit */ if (crash_mem_ranges == max_crash_mem_ranges) { int ret; ret = allocate_crash_memory_ranges(); if (ret) return ret; } start = base; crash_memory_ranges[crash_mem_ranges].base = start; crash_mem_ranges++; } crash_memory_ranges[crash_mem_ranges - 1].size = (end - start); pr_debug("crash_memory_range[%d] [%#016llx-%#016llx], %#llx bytes\n", (crash_mem_ranges - 1), start, end - 1, (end - start)); return 0; } static int fadump_exclude_reserved_area(unsigned long long start, unsigned long long end) { unsigned long long ra_start, ra_end; int ret = 0; 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)) { ret = fadump_add_crash_memory(start, ra_start); if (ret) return ret; ret = fadump_add_crash_memory(ra_end, end); } else if (start < ra_start) { ret = fadump_add_crash_memory(start, ra_start); } else if (ra_end < end) { ret = fadump_add_crash_memory(ra_end, end); } } else ret = fadump_add_crash_memory(start, end); return ret; } 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; #if defined(_CALL_ELF) elf->e_flags = _CALL_ELF; #else elf->e_flags = 0; #endif 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 int fadump_setup_crash_memory_ranges(void) { struct memblock_region *reg; unsigned long long start, end; int ret; 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. */ ret = fadump_add_crash_memory(RMA_START, fw_dump.boot_memory_size); if (ret) return ret; for_each_memblock(memory, reg) { start = (unsigned long long)reg->base; end = start + (unsigned long long)reg->size; /* * skip the first memory chunk that is already added (RMA_START * through boot_memory_size). This logic needs a relook if and * when RMA_START changes to a non-zero value. */ BUILD_BUG_ON(RMA_START != 0); if (start < fw_dump.boot_memory_size) { if (end > fw_dump.boot_memory_size) start = fw_dump.boot_memory_size; else continue; } /* add this range excluding the reserved dump area. */ ret = fadump_exclude_reserved_area(start, end); if (ret) return ret; } return 0; } /* * 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 be64_to_cpu(fdm.rmr_region.destination_address) + paddr; else return paddr; } static int fadump_create_elfcore_headers(char *bufp) { struct elfhdr *elf; struct elf_phdr *phdr; int i; fadump_init_elfcore_header(bufp); elf = (struct elfhdr *)bufp; bufp += sizeof(struct elfhdr); /* * setup ELF PT_NOTE, place holder for cpu notes info. The notes info * will be populated during second kernel boot after crash. Hence * this PT_NOTE will always be the first elf note. * * NOTE: Any new ELF note addition should be placed after this note. */ phdr = (struct elf_phdr *)bufp; bufp += sizeof(struct elf_phdr); phdr->p_type = PT_NOTE; phdr->p_flags = 0; phdr->p_vaddr = 0; phdr->p_align = 0; phdr->p_offset = 0; phdr->p_paddr = 0; phdr->p_filesz = 0; phdr->p_memsz = 0; (elf->e_phnum)++; /* setup ELF PT_NOTE for vmcoreinfo */ phdr = (struct elf_phdr *)bufp; bufp += sizeof(struct elf_phdr); phdr->p_type = PT_NOTE; phdr->p_flags = 0; phdr->p_vaddr = 0; phdr->p_align = 0; phdr->p_paddr = fadump_relocate(paddr_vmcoreinfo_note()); phdr->p_offset = phdr->p_paddr; phdr->p_memsz = phdr->p_filesz = VMCOREINFO_NOTE_SIZE; /* Increment number of program headers. */ (elf->e_phnum)++; /* setup PT_LOAD sections. */ for (i = 0; i < crash_mem_ranges; i++) { unsigned long long mbase, msize; mbase = crash_memory_ranges[i].base; msize = crash_memory_ranges[i].size; if (!msize) continue; phdr = (struct elf_phdr *)bufp; bufp += sizeof(struct elf_phdr); phdr->p_type = PT_LOAD; phdr->p_flags = PF_R|PF_W|PF_X; phdr->p_offset = mbase; if (mbase == RMA_START) { /* * The entire RMA region will be moved by firmware * to the specified destination_address. Hence set * the correct offset. */ phdr->p_offset = be64_to_cpu(fdm.rmr_region.destination_address); } phdr->p_paddr = mbase; phdr->p_vaddr = (unsigned long)__va(mbase); phdr->p_filesz = msize; phdr->p_memsz = msize; phdr->p_align = 0; /* Increment number of program headers. */ (elf->e_phnum)++; } return 0; } static unsigned long init_fadump_header(unsigned long addr) { struct fadump_crash_info_header *fdh; if (!addr) return 0; fw_dump.fadumphdr_addr = addr; fdh = __va(addr); addr += sizeof(struct fadump_crash_info_header); memset(fdh, 0, sizeof(struct fadump_crash_info_header)); fdh->magic_number = FADUMP_CRASH_INFO_MAGIC; fdh->elfcorehdr_addr = addr; /* We will set the crashing cpu id in crash_fadump() during crash. */ fdh->crashing_cpu = CPU_UNKNOWN; return addr; } static int register_fadump(void) { unsigned long addr; void *vaddr; int ret; /* * If no memory is reserved then we can not register for firmware- * assisted dump. */ if (!fw_dump.reserve_dump_area_size) return -ENODEV; ret = fadump_setup_crash_memory_ranges(); if (ret) return ret; addr = be64_to_cpu(fdm.rmr_region.destination_address) + be64_to_cpu(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. */ return 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(const 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) { pr_err("Failed to invalidate firmware-assisted dump registration. 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) { /* pass the same memory dump structure provided by platform */ fadump_invalidate_dump(fdm_active); } else if (fw_dump.dump_registered) { /* Un-register Firmware-assisted dump if it was registered. */ fadump_unregister_dump(&fdm); free_crash_memory_ranges(); } } static void fadump_free_reserved_memory(unsigned long start_pfn, unsigned long end_pfn) { unsigned long pfn; unsigned long time_limit = jiffies + HZ; pr_info("freeing reserved memory (0x%llx - 0x%llx)\n", PFN_PHYS(start_pfn), PFN_PHYS(end_pfn)); for (pfn = start_pfn; pfn < end_pfn; pfn++) { free_reserved_page(pfn_to_page(pfn)); if (time_after(jiffies, time_limit)) { cond_resched(); time_limit = jiffies + HZ; } } } /* * Skip memory holes and free memory that was actually reserved. */ static void fadump_release_reserved_area(unsigned long start, unsigned long end) { struct memblock_region *reg; unsigned long tstart, tend; unsigned long start_pfn = PHYS_PFN(start); unsigned long end_pfn = PHYS_PFN(end); for_each_memblock(memory, reg) { tstart = max(start_pfn, memblock_region_memory_base_pfn(reg)); tend = min(end_pfn, memblock_region_memory_end_pfn(reg)); if (tstart < tend) { fadump_free_reserved_memory(tstart, tend); if (tend == end_pfn) break; start_pfn = tend + 1; } } } /* * 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 ra_start, ra_end; ra_start = fw_dump.reserve_dump_area_start; ra_end = ra_start + fw_dump.reserve_dump_area_size; /* * exclude the dump reserve area. Will reuse it for next * fadump registration. */ if (begin < ra_end && end > ra_start) { if (begin < ra_start) fadump_release_reserved_area(begin, ra_start); if (end > ra_end) fadump_release_reserved_area(ra_end, end); } else fadump_release_reserved_area(begin, end); } 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 = be64_to_cpu(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) { int input = -1; if (!fw_dump.dump_active) return -EPERM; if (kstrtoint(buf, 0, &input)) return -EINVAL; if (input == 1) { /* * Take away the '/proc/vmcore'. We are releasing the dump * memory, hence it will not be valid anymore. */ #ifdef CONFIG_PROC_VMCORE vmcore_cleanup(); #endif 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; int input = -1; if (!fw_dump.fadump_enabled || fdm_active) return -EPERM; if (kstrtoint(buf, 0, &input)) return -EINVAL; mutex_lock(&fadump_mutex); switch (input) { case 0: if (fw_dump.dump_registered == 0) { goto unlock_out; } /* Un-register Firmware-assisted dump */ fadump_unregister_dump(&fdm); break; case 1: if (fw_dump.dump_registered == 1) { /* Un-register Firmware-assisted dump */ fadump_unregister_dump(&fdm); } /* Register Firmware-assisted dump */ ret = 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", be64_to_cpu(fdm_ptr->cpu_state_data.destination_address), be64_to_cpu(fdm_ptr->cpu_state_data.destination_address) + be64_to_cpu(fdm_ptr->cpu_state_data.source_len) - 1, be64_to_cpu(fdm_ptr->cpu_state_data.source_len), be64_to_cpu(fdm_ptr->cpu_state_data.bytes_dumped)); seq_printf(m, "HPTE: [%#016llx-%#016llx] %#llx bytes, " "Dumped: %#llx\n", be64_to_cpu(fdm_ptr->hpte_region.destination_address), be64_to_cpu(fdm_ptr->hpte_region.destination_address) + be64_to_cpu(fdm_ptr->hpte_region.source_len) - 1, be64_to_cpu(fdm_ptr->hpte_region.source_len), be64_to_cpu(fdm_ptr->hpte_region.bytes_dumped)); seq_printf(m, "DUMP: [%#016llx-%#016llx] %#llx bytes, " "Dumped: %#llx\n", be64_to_cpu(fdm_ptr->rmr_region.destination_address), be64_to_cpu(fdm_ptr->rmr_region.destination_address) + be64_to_cpu(fdm_ptr->rmr_region.source_len) - 1, be64_to_cpu(fdm_ptr->rmr_region.source_len), be64_to_cpu(fdm_ptr->rmr_region.bytes_dumped)); if (!fdm_active || (fw_dump.reserve_dump_area_start == be64_to_cpu(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, be64_to_cpu(fdm_ptr->cpu_state_data.destination_address) - 1, be64_to_cpu(fdm_ptr->cpu_state_data.destination_address) - fw_dump.reserve_dump_area_start, be64_to_cpu(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); DEFINE_SHOW_ATTRIBUTE(fadump_region); static void fadump_init_files(void) { struct dentry *debugfs_file; int rc = 0; rc = sysfs_create_file(kernel_kobj, &fadump_attr.attr); if (rc) printk(KERN_ERR "fadump: unable to create sysfs file" " fadump_enabled (%d)\n", rc); rc = sysfs_create_file(kernel_kobj, &fadump_register_attr.attr); if (rc) printk(KERN_ERR "fadump: unable to create sysfs file" " fadump_registered (%d)\n", rc); debugfs_file = debugfs_create_file("fadump_region", 0444, powerpc_debugfs_root, NULL, &fadump_region_fops); if (!debugfs_file) printk(KERN_ERR "fadump: unable to create debugfs file" " fadump_region\n"); if (fw_dump.dump_active) { rc = sysfs_create_file(kernel_kobj, &fadump_release_attr.attr); if (rc) printk(KERN_ERR "fadump: unable to create sysfs file" " fadump_release_mem (%d)\n", rc); } return; } /* * Prepare for firmware-assisted dump. */ int __init setup_fadump(void) { if (!fw_dump.fadump_enabled) return 0; if (!fw_dump.fadump_supported) { printk(KERN_ERR "Firmware-assisted dump is not supported on" " this hardware\n"); return 0; } fadump_show_config(); /* * If dump data is available then see if it is valid and prepare for * saving it to the disk. */ if (fw_dump.dump_active) { /* * if dump process fails then invalidate the registration * and release memory before proceeding for re-registration. */ if (process_fadump(fdm_active) < 0) fadump_invalidate_release_mem(); } /* Initialize the kernel dump memory structure for FAD registration. */ else if (fw_dump.reserve_dump_area_size) init_fadump_mem_struct(&fdm, fw_dump.reserve_dump_area_start); fadump_init_files(); return 1; } subsys_initcall(setup_fadump);