// 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 #include /* * The CPU who acquired the lock to trigger the fadump crash should * wait for other CPUs to enter. * * The timeout is in milliseconds. */ #define CRASH_TIMEOUT 500 static struct fw_dump fw_dump; static void __init fadump_reserve_crash_area(u64 base); #ifndef CONFIG_PRESERVE_FA_DUMP static struct kobject *fadump_kobj; static atomic_t cpus_in_fadump; static DEFINE_MUTEX(fadump_mutex); static struct fadump_mrange_info crash_mrange_info = { "crash", NULL, 0, 0, 0, false }; #define RESERVED_RNGS_SZ 16384 /* 16K - 128 entries */ #define RESERVED_RNGS_CNT (RESERVED_RNGS_SZ / \ sizeof(struct fadump_memory_range)) static struct fadump_memory_range rngs[RESERVED_RNGS_CNT]; static struct fadump_mrange_info reserved_mrange_info = { "reserved", rngs, RESERVED_RNGS_SZ, 0, RESERVED_RNGS_CNT, true }; static void __init early_init_dt_scan_reserved_ranges(unsigned long node); #ifdef CONFIG_CMA static struct cma *fadump_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. */ static 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) { if (depth == 0) { early_init_dt_scan_reserved_ranges(node); return 0; } if (depth != 1) return 0; if (strcmp(uname, "rtas") == 0) { rtas_fadump_dt_scan(&fw_dump, node); return 1; } if (strcmp(uname, "ibm,opal") == 0) { opal_fadump_dt_scan(&fw_dump, node); return 1; } return 0; } /* * 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, unsigned long size) { u64 d_start, d_end; if (!fw_dump.dump_registered) return 0; if (!size) return 0; d_start = fw_dump.reserve_dump_area_start; d_end = d_start + fw_dump.reserve_dump_area_size; if (((addr + size) > d_start) && (addr <= d_end)) return 1; return (addr <= fw_dump.boot_mem_top); } 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 true, if there are no holes in memory area between d_start to d_end, * false otherwise. */ static bool is_fadump_mem_area_contiguous(u64 d_start, u64 d_end) { phys_addr_t reg_start, reg_end; bool ret = false; u64 i, start, end; for_each_mem_range(i, ®_start, ®_end) { start = max_t(u64, d_start, reg_start); end = min_t(u64, d_end, reg_end); if (d_start < end) { /* Memory hole from d_start to start */ if (start > d_start) break; if (end == d_end) { ret = true; break; } d_start = end + 1; } } return ret; } /* * Returns true, if there are no holes in boot memory area, * false otherwise. */ bool is_fadump_boot_mem_contiguous(void) { unsigned long d_start, d_end; bool ret = false; int i; for (i = 0; i < fw_dump.boot_mem_regs_cnt; i++) { d_start = fw_dump.boot_mem_addr[i]; d_end = d_start + fw_dump.boot_mem_sz[i]; ret = is_fadump_mem_area_contiguous(d_start, d_end); if (!ret) break; } return ret; } /* * Returns true, if there are no holes in reserved memory area, * false otherwise. */ bool is_fadump_reserved_mem_contiguous(void) { u64 d_start, d_end; d_start = fw_dump.reserve_dump_area_start; d_end = d_start + fw_dump.reserve_dump_area_size; return is_fadump_mem_area_contiguous(d_start, d_end); } /* Print firmware assisted dump configurations for debugging purpose. */ static void __init fadump_show_config(void) { int i; 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); pr_debug(" Boot memory top : %llx\n", fw_dump.boot_mem_top); pr_debug("Boot memory regions cnt: %llx\n", fw_dump.boot_mem_regs_cnt); for (i = 0; i < fw_dump.boot_mem_regs_cnt; i++) { pr_debug("[%03d] base = %llx, size = %llx\n", i, fw_dump.boot_mem_addr[i], fw_dump.boot_mem_sz[i]); } } /** * 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 __init u64 fadump_calculate_reserve_size(void) { u64 base, size, bootmem_min; int ret; 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; bootmem_min = fw_dump.ops->fadump_get_bootmem_min(); return (size > bootmem_min ? size : bootmem_min); } /* * Calculate the total memory size required to be reserved for * firmware-assisted dump registration. */ static unsigned long __init 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); /* This is to hold kernel metadata on platforms that support it */ size += (fw_dump.ops->fadump_get_metadata_size ? fw_dump.ops->fadump_get_metadata_size() : 0); return size; } static int __init add_boot_mem_region(unsigned long rstart, unsigned long rsize) { int i = fw_dump.boot_mem_regs_cnt++; if (fw_dump.boot_mem_regs_cnt > FADUMP_MAX_MEM_REGS) { fw_dump.boot_mem_regs_cnt = FADUMP_MAX_MEM_REGS; return 0; } pr_debug("Added boot memory range[%d] [%#016lx-%#016lx)\n", i, rstart, (rstart + rsize)); fw_dump.boot_mem_addr[i] = rstart; fw_dump.boot_mem_sz[i] = rsize; return 1; } /* * Firmware usually has a hard limit on the data it can copy per region. * Honour that by splitting a memory range into multiple regions. */ static int __init add_boot_mem_regions(unsigned long mstart, unsigned long msize) { unsigned long rstart, rsize, max_size; int ret = 1; rstart = mstart; max_size = fw_dump.max_copy_size ? fw_dump.max_copy_size : msize; while (msize) { if (msize > max_size) rsize = max_size; else rsize = msize; ret = add_boot_mem_region(rstart, rsize); if (!ret) break; msize -= rsize; rstart += rsize; } return ret; } static int __init fadump_get_boot_mem_regions(void) { unsigned long size, cur_size, hole_size, last_end; unsigned long mem_size = fw_dump.boot_memory_size; phys_addr_t reg_start, reg_end; int ret = 1; u64 i; fw_dump.boot_mem_regs_cnt = 0; last_end = 0; hole_size = 0; cur_size = 0; for_each_mem_range(i, ®_start, ®_end) { size = reg_end - reg_start; hole_size += (reg_start - last_end); if ((cur_size + size) >= mem_size) { size = (mem_size - cur_size); ret = add_boot_mem_regions(reg_start, size); break; } mem_size -= size; cur_size += size; ret = add_boot_mem_regions(reg_start, size); if (!ret) break; last_end = reg_end; } fw_dump.boot_mem_top = PAGE_ALIGN(fw_dump.boot_memory_size + hole_size); return ret; } /* * Returns true, if the given range overlaps with reserved memory ranges * starting at idx. Also, updates idx to index of overlapping memory range * with the given memory range. * False, otherwise. */ static bool __init overlaps_reserved_ranges(u64 base, u64 end, int *idx) { bool ret = false; int i; for (i = *idx; i < reserved_mrange_info.mem_range_cnt; i++) { u64 rbase = reserved_mrange_info.mem_ranges[i].base; u64 rend = rbase + reserved_mrange_info.mem_ranges[i].size; if (end <= rbase) break; if ((end > rbase) && (base < rend)) { *idx = i; ret = true; break; } } return ret; } /* * Locate a suitable memory area to reserve memory for FADump. While at it, * lookup reserved-ranges & avoid overlap with them, as they are used by F/W. */ static u64 __init fadump_locate_reserve_mem(u64 base, u64 size) { struct fadump_memory_range *mrngs; phys_addr_t mstart, mend; int idx = 0; u64 i, ret = 0; mrngs = reserved_mrange_info.mem_ranges; for_each_free_mem_range(i, NUMA_NO_NODE, MEMBLOCK_NONE, &mstart, &mend, NULL) { pr_debug("%llu) mstart: %llx, mend: %llx, base: %llx\n", i, mstart, mend, base); if (mstart > base) base = PAGE_ALIGN(mstart); while ((mend > base) && ((mend - base) >= size)) { if (!overlaps_reserved_ranges(base, base+size, &idx)) { ret = base; goto out; } base = mrngs[idx].base + mrngs[idx].size; base = PAGE_ALIGN(base); } } out: return ret; } int __init fadump_reserve_mem(void) { u64 base, size, mem_boundary, bootmem_min; int ret = 1; if (!fw_dump.fadump_enabled) return 0; if (!fw_dump.fadump_supported) { pr_info("Firmware-Assisted Dump is not supported on this hardware\n"); goto error_out; } /* * Initialize boot memory size * If dump is active then we have already calculated the size during * first kernel. */ if (!fw_dump.dump_active) { fw_dump.boot_memory_size = PAGE_ALIGN(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 bootmem_min = fw_dump.ops->fadump_get_bootmem_min(); if (fw_dump.boot_memory_size < bootmem_min) { pr_err("Can't enable fadump with boot memory size (0x%lx) less than 0x%llx\n", fw_dump.boot_memory_size, bootmem_min); goto error_out; } if (!fadump_get_boot_mem_regions()) { pr_err("Too many holes in boot memory area to enable fadump\n"); goto error_out; } } /* * 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) mem_boundary = memory_limit; else mem_boundary = memblock_end_of_DRAM(); base = fw_dump.boot_mem_top; size = get_fadump_area_size(); fw_dump.reserve_dump_area_size = size; 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 * can be released for general use by invalidating fadump. */ fadump_reserve_crash_area(base); pr_debug("fadumphdr_addr = %#016lx\n", fw_dump.fadumphdr_addr); pr_debug("Reserve dump area start address: 0x%lx\n", fw_dump.reserve_dump_area_start); } else { /* * Reserve memory at an offset closer to bottom of the RAM to * minimize the impact of memory hot-remove operation. */ base = fadump_locate_reserve_mem(base, size); if (!base || (base + size > mem_boundary)) { pr_err("Failed to find memory chunk for reservation!\n"); goto error_out; } fw_dump.reserve_dump_area_start = base; /* * Calculate the kernel metadata address and register it with * f/w if the platform supports. */ if (fw_dump.ops->fadump_setup_metadata && (fw_dump.ops->fadump_setup_metadata(&fw_dump) < 0)) goto error_out; if (memblock_reserve(base, size)) { pr_err("Failed to reserve memory!\n"); goto error_out; } pr_info("Reserved %lldMB of memory at %#016llx (System RAM: %lldMB)\n", (size >> 20), base, (memblock_phys_mem_size() >> 20)); ret = fadump_cma_init(); } return ret; error_out: fw_dump.fadump_enabled = 0; return 0; } /* 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); void crash_fadump(struct pt_regs *regs, const char *str) { unsigned int msecs; struct fadump_crash_info_header *fdh = NULL; int old_cpu, this_cpu; /* Do not include first CPU */ unsigned int ncpus = num_online_cpus() - 1; 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) { atomic_inc(&cpus_in_fadump); /* * 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; /* * If we came in via system reset, wait a while for the secondary * CPUs to enter. */ if (TRAP(&(fdh->regs)) == INTERRUPT_SYSTEM_RESET) { msecs = CRASH_TIMEOUT; while ((atomic_read(&cpus_in_fadump) < ncpus) && (--msecs > 0)) mdelay(1); } fw_dump.ops->fadump_trigger(fdh, str); } u32 *__init 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; } void __init fadump_update_elfcore_header(char *bufp) { struct elf_phdr *phdr; 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 = __pa(fw_dump.cpu_notes_buf_vaddr); 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 *__init fadump_alloc_buffer(unsigned long size) { unsigned long count, i; struct page *page; void *vaddr; vaddr = alloc_pages_exact(size, GFP_KERNEL | __GFP_ZERO); if (!vaddr) return NULL; count = PAGE_ALIGN(size) / PAGE_SIZE; page = virt_to_page(vaddr); for (i = 0; i < count; i++) mark_page_reserved(page + i); return vaddr; } static void fadump_free_buffer(unsigned long vaddr, unsigned long size) { free_reserved_area((void *)vaddr, (void *)(vaddr + size), -1, NULL); } s32 __init fadump_setup_cpu_notes_buf(u32 num_cpus) { /* 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); fw_dump.cpu_notes_buf_vaddr = (unsigned long)fadump_alloc_buffer(fw_dump.cpu_notes_buf_size); if (!fw_dump.cpu_notes_buf_vaddr) { pr_err("Failed to allocate %ld bytes for CPU notes buffer\n", fw_dump.cpu_notes_buf_size); return -ENOMEM; } pr_debug("Allocated buffer for cpu notes of size %ld at 0x%lx\n", fw_dump.cpu_notes_buf_size, fw_dump.cpu_notes_buf_vaddr); return 0; } void fadump_free_cpu_notes_buf(void) { if (!fw_dump.cpu_notes_buf_vaddr) return; fadump_free_buffer(fw_dump.cpu_notes_buf_vaddr, fw_dump.cpu_notes_buf_size); fw_dump.cpu_notes_buf_vaddr = 0; fw_dump.cpu_notes_buf_size = 0; } static void fadump_free_mem_ranges(struct fadump_mrange_info *mrange_info) { if (mrange_info->is_static) { mrange_info->mem_range_cnt = 0; return; } kfree(mrange_info->mem_ranges); memset((void *)((u64)mrange_info + RNG_NAME_SZ), 0, (sizeof(struct fadump_mrange_info) - RNG_NAME_SZ)); } /* * Allocate or reallocate mem_ranges array in incremental units * of PAGE_SIZE. */ static int fadump_alloc_mem_ranges(struct fadump_mrange_info *mrange_info) { struct fadump_memory_range *new_array; u64 new_size; new_size = mrange_info->mem_ranges_sz + PAGE_SIZE; pr_debug("Allocating %llu bytes of memory for %s memory ranges\n", new_size, mrange_info->name); new_array = krealloc(mrange_info->mem_ranges, new_size, GFP_KERNEL); if (new_array == NULL) { pr_err("Insufficient memory for setting up %s memory ranges\n", mrange_info->name); fadump_free_mem_ranges(mrange_info); return -ENOMEM; } mrange_info->mem_ranges = new_array; mrange_info->mem_ranges_sz = new_size; mrange_info->max_mem_ranges = (new_size / sizeof(struct fadump_memory_range)); return 0; } static inline int fadump_add_mem_range(struct fadump_mrange_info *mrange_info, u64 base, u64 end) { struct fadump_memory_range *mem_ranges = mrange_info->mem_ranges; bool is_adjacent = false; u64 start, size; if (base == end) return 0; /* * Fold adjacent memory ranges to bring down the memory ranges/ * PT_LOAD segments count. */ if (mrange_info->mem_range_cnt) { start = mem_ranges[mrange_info->mem_range_cnt - 1].base; size = mem_ranges[mrange_info->mem_range_cnt - 1].size; if ((start + size) == base) is_adjacent = true; } if (!is_adjacent) { /* resize the array on reaching the limit */ if (mrange_info->mem_range_cnt == mrange_info->max_mem_ranges) { int ret; if (mrange_info->is_static) { pr_err("Reached array size limit for %s memory ranges\n", mrange_info->name); return -ENOSPC; } ret = fadump_alloc_mem_ranges(mrange_info); if (ret) return ret; /* Update to the new resized array */ mem_ranges = mrange_info->mem_ranges; } start = base; mem_ranges[mrange_info->mem_range_cnt].base = start; mrange_info->mem_range_cnt++; } mem_ranges[mrange_info->mem_range_cnt - 1].size = (end - start); pr_debug("%s_memory_range[%d] [%#016llx-%#016llx], %#llx bytes\n", mrange_info->name, (mrange_info->mem_range_cnt - 1), start, end - 1, (end - start)); return 0; } static int fadump_exclude_reserved_area(u64 start, u64 end) { u64 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_mem_range(&crash_mrange_info, start, ra_start); if (ret) return ret; ret = fadump_add_mem_range(&crash_mrange_info, ra_end, end); } else if (start < ra_start) { ret = fadump_add_mem_range(&crash_mrange_info, start, ra_start); } else if (ra_end < end) { ret = fadump_add_mem_range(&crash_mrange_info, ra_end, end); } } else ret = fadump_add_mem_range(&crash_mrange_info, 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) { u64 i, start, end; int ret; pr_debug("Setup crash memory ranges.\n"); crash_mrange_info.mem_range_cnt = 0; /* * Boot memory region(s) registered with firmware are moved to * different location at the time of crash. Create separate program * header(s) for this memory chunk(s) with the correct offset. */ for (i = 0; i < fw_dump.boot_mem_regs_cnt; i++) { start = fw_dump.boot_mem_addr[i]; end = start + fw_dump.boot_mem_sz[i]; ret = fadump_add_mem_range(&crash_mrange_info, start, end); if (ret) return ret; } for_each_mem_range(i, &start, &end) { /* * skip the memory chunk that is already added * (0 through boot_memory_top). */ if (start < fw_dump.boot_mem_top) { if (end > fw_dump.boot_mem_top) start = fw_dump.boot_mem_top; 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) { unsigned long raddr, rstart, rend, rlast, hole_size; int i; hole_size = 0; rlast = 0; raddr = paddr; for (i = 0; i < fw_dump.boot_mem_regs_cnt; i++) { rstart = fw_dump.boot_mem_addr[i]; rend = rstart + fw_dump.boot_mem_sz[i]; hole_size += (rstart - rlast); if (paddr >= rstart && paddr < rend) { raddr += fw_dump.boot_mem_dest_addr - hole_size; break; } rlast = rend; } pr_debug("vmcoreinfo: paddr = 0x%lx, raddr = 0x%lx\n", paddr, raddr); return raddr; } static int fadump_create_elfcore_headers(char *bufp) { unsigned long long raddr, offset; struct elf_phdr *phdr; struct elfhdr *elf; int i, j; 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. */ j = 0; offset = 0; raddr = fw_dump.boot_mem_addr[0]; for (i = 0; i < crash_mrange_info.mem_range_cnt; i++) { u64 mbase, msize; mbase = crash_mrange_info.mem_ranges[i].base; msize = crash_mrange_info.mem_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 == raddr) { /* * The entire real memory region will be moved by * firmware to the specified destination_address. * Hence set the correct offset. */ phdr->p_offset = fw_dump.boot_mem_dest_addr + offset; if (j < (fw_dump.boot_mem_regs_cnt - 1)) { offset += fw_dump.boot_mem_sz[j]; raddr = fw_dump.boot_mem_addr[++j]; } } 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; 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 = FADUMP_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 = fw_dump.fadumphdr_addr; /* 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. */ pr_debug("Registering for firmware-assisted kernel dump...\n"); return fw_dump.ops->fadump_register(&fw_dump); } void fadump_cleanup(void) { if (!fw_dump.fadump_supported) return; /* Invalidate the registration only if dump is active. */ if (fw_dump.dump_active) { pr_debug("Invalidating firmware-assisted dump registration\n"); fw_dump.ops->fadump_invalidate(&fw_dump); } else if (fw_dump.dump_registered) { /* Un-register Firmware-assisted dump if it was registered. */ fw_dump.ops->fadump_unregister(&fw_dump); fadump_free_mem_ranges(&crash_mrange_info); } if (fw_dump.ops->fadump_cleanup) fw_dump.ops->fadump_cleanup(&fw_dump); } 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(u64 start, u64 end) { unsigned long reg_spfn, reg_epfn; u64 tstart, tend, spfn, epfn; int i; spfn = PHYS_PFN(start); epfn = PHYS_PFN(end); for_each_mem_pfn_range(i, MAX_NUMNODES, ®_spfn, ®_epfn, NULL) { tstart = max_t(u64, spfn, reg_spfn); tend = min_t(u64, epfn, reg_epfn); if (tstart < tend) { fadump_free_reserved_memory(tstart, tend); if (tend == epfn) break; spfn = tend; } } } /* * Sort the mem ranges in-place and merge adjacent ranges * to minimize the memory ranges count. */ static void sort_and_merge_mem_ranges(struct fadump_mrange_info *mrange_info) { struct fadump_memory_range *mem_ranges; struct fadump_memory_range tmp_range; u64 base, size; int i, j, idx; if (!reserved_mrange_info.mem_range_cnt) return; /* Sort the memory ranges */ mem_ranges = mrange_info->mem_ranges; for (i = 0; i < mrange_info->mem_range_cnt; i++) { idx = i; for (j = (i + 1); j < mrange_info->mem_range_cnt; j++) { if (mem_ranges[idx].base > mem_ranges[j].base) idx = j; } if (idx != i) { tmp_range = mem_ranges[idx]; mem_ranges[idx] = mem_ranges[i]; mem_ranges[i] = tmp_range; } } /* Merge adjacent reserved ranges */ idx = 0; for (i = 1; i < mrange_info->mem_range_cnt; i++) { base = mem_ranges[i-1].base; size = mem_ranges[i-1].size; if (mem_ranges[i].base == (base + size)) mem_ranges[idx].size += mem_ranges[i].size; else { idx++; if (i == idx) continue; mem_ranges[idx] = mem_ranges[i]; } } mrange_info->mem_range_cnt = idx + 1; } /* * Scan reserved-ranges to consider them while reserving/releasing * memory for FADump. */ static void __init early_init_dt_scan_reserved_ranges(unsigned long node) { const __be32 *prop; int len, ret = -1; unsigned long i; /* reserved-ranges already scanned */ if (reserved_mrange_info.mem_range_cnt != 0) return; prop = of_get_flat_dt_prop(node, "reserved-ranges", &len); if (!prop) return; /* * Each reserved range is an (address,size) pair, 2 cells each, * totalling 4 cells per range. */ for (i = 0; i < len / (sizeof(*prop) * 4); i++) { u64 base, size; base = of_read_number(prop + (i * 4) + 0, 2); size = of_read_number(prop + (i * 4) + 2, 2); if (size) { ret = fadump_add_mem_range(&reserved_mrange_info, base, base + size); if (ret < 0) { pr_warn("some reserved ranges are ignored!\n"); break; } } } /* Compact reserved ranges */ sort_and_merge_mem_ranges(&reserved_mrange_info); } /* * Release the memory that was reserved during early boot to preserve the * crash'ed kernel's memory contents except reserved dump area (permanent * reservation) and reserved ranges used by F/W. The released memory will * be available for general use. */ static void fadump_release_memory(u64 begin, u64 end) { u64 ra_start, ra_end, tstart; int i, ret; ra_start = fw_dump.reserve_dump_area_start; ra_end = ra_start + fw_dump.reserve_dump_area_size; /* * If reserved ranges array limit is hit, overwrite the last reserved * memory range with reserved dump area to ensure it is excluded from * the memory being released (reused for next FADump registration). */ if (reserved_mrange_info.mem_range_cnt == reserved_mrange_info.max_mem_ranges) reserved_mrange_info.mem_range_cnt--; ret = fadump_add_mem_range(&reserved_mrange_info, ra_start, ra_end); if (ret != 0) return; /* Get the reserved ranges list in order first. */ sort_and_merge_mem_ranges(&reserved_mrange_info); /* Exclude reserved ranges and release remaining memory */ tstart = begin; for (i = 0; i < reserved_mrange_info.mem_range_cnt; i++) { ra_start = reserved_mrange_info.mem_ranges[i].base; ra_end = ra_start + reserved_mrange_info.mem_ranges[i].size; if (tstart >= ra_end) continue; if (tstart < ra_start) fadump_release_reserved_area(tstart, ra_start); tstart = ra_end; } if (tstart < end) fadump_release_reserved_area(tstart, end); } static void fadump_invalidate_release_mem(void) { mutex_lock(&fadump_mutex); if (!fw_dump.dump_active) { mutex_unlock(&fadump_mutex); return; } fadump_cleanup(); mutex_unlock(&fadump_mutex); fadump_release_memory(fw_dump.boot_mem_top, memblock_end_of_DRAM()); fadump_free_cpu_notes_buf(); /* * Setup kernel metadata and initialize the kernel dump * memory structure for FADump re-registration. */ if (fw_dump.ops->fadump_setup_metadata && (fw_dump.ops->fadump_setup_metadata(&fw_dump) < 0)) pr_warn("Failed to setup kernel metadata!\n"); fw_dump.ops->fadump_init_mem_struct(&fw_dump); } static ssize_t release_mem_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; } /* Release the reserved memory and disable the FADump */ static void __init unregister_fadump(void) { fadump_cleanup(); fadump_release_memory(fw_dump.reserve_dump_area_start, fw_dump.reserve_dump_area_size); fw_dump.fadump_enabled = 0; kobject_put(fadump_kobj); } static ssize_t enabled_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) { return sprintf(buf, "%d\n", fw_dump.fadump_enabled); } static ssize_t mem_reserved_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) { return sprintf(buf, "%ld\n", fw_dump.reserve_dump_area_size); } static ssize_t registered_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) { return sprintf(buf, "%d\n", fw_dump.dump_registered); } static ssize_t registered_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 || fw_dump.dump_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 */ pr_debug("Un-register firmware-assisted dump\n"); fw_dump.ops->fadump_unregister(&fw_dump); break; case 1: if (fw_dump.dump_registered == 1) { /* Un-register Firmware-assisted dump */ fw_dump.ops->fadump_unregister(&fw_dump); } /* 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) { if (!fw_dump.fadump_enabled) return 0; mutex_lock(&fadump_mutex); fw_dump.ops->fadump_region_show(&fw_dump, m); mutex_unlock(&fadump_mutex); return 0; } static struct kobj_attribute release_attr = __ATTR_WO(release_mem); static struct kobj_attribute enable_attr = __ATTR_RO(enabled); static struct kobj_attribute register_attr = __ATTR_RW(registered); static struct kobj_attribute mem_reserved_attr = __ATTR_RO(mem_reserved); static struct attribute *fadump_attrs[] = { &enable_attr.attr, ®ister_attr.attr, &mem_reserved_attr.attr, NULL, }; ATTRIBUTE_GROUPS(fadump); DEFINE_SHOW_ATTRIBUTE(fadump_region); static void __init fadump_init_files(void) { int rc = 0; fadump_kobj = kobject_create_and_add("fadump", kernel_kobj); if (!fadump_kobj) { pr_err("failed to create fadump kobject\n"); return; } debugfs_create_file("fadump_region", 0444, arch_debugfs_dir, NULL, &fadump_region_fops); if (fw_dump.dump_active) { rc = sysfs_create_file(fadump_kobj, &release_attr.attr); if (rc) pr_err("unable to create release_mem sysfs file (%d)\n", rc); } rc = sysfs_create_groups(fadump_kobj, fadump_groups); if (rc) { pr_err("sysfs group creation failed (%d), unregistering FADump", rc); unregister_fadump(); return; } /* * The FADump sysfs are moved from kernel_kobj to fadump_kobj need to * create symlink at old location to maintain backward compatibility. * * - fadump_enabled -> fadump/enabled * - fadump_registered -> fadump/registered * - fadump_release_mem -> fadump/release_mem */ rc = compat_only_sysfs_link_entry_to_kobj(kernel_kobj, fadump_kobj, "enabled", "fadump_enabled"); if (rc) { pr_err("unable to create fadump_enabled symlink (%d)", rc); return; } rc = compat_only_sysfs_link_entry_to_kobj(kernel_kobj, fadump_kobj, "registered", "fadump_registered"); if (rc) { pr_err("unable to create fadump_registered symlink (%d)", rc); sysfs_remove_link(kernel_kobj, "fadump_enabled"); return; } if (fw_dump.dump_active) { rc = compat_only_sysfs_link_entry_to_kobj(kernel_kobj, fadump_kobj, "release_mem", "fadump_release_mem"); if (rc) pr_err("unable to create fadump_release_mem symlink (%d)", rc); } return; } /* * Prepare for firmware-assisted dump. */ int __init setup_fadump(void) { if (!fw_dump.fadump_supported) return 0; fadump_init_files(); fadump_show_config(); if (!fw_dump.fadump_enabled) return 1; /* * 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 (fw_dump.ops->fadump_process(&fw_dump) < 0) fadump_invalidate_release_mem(); } /* Initialize the kernel dump memory structure and register with f/w */ else if (fw_dump.reserve_dump_area_size) { fw_dump.ops->fadump_init_mem_struct(&fw_dump); register_fadump(); } /* * In case of panic, fadump is triggered via ppc_panic_event() * panic notifier. Setting crash_kexec_post_notifiers to 'true' * lets panic() function take crash friendly path before panic * notifiers are invoked. */ crash_kexec_post_notifiers = true; return 1; } /* * Use subsys_initcall_sync() here because there is dependency with * crash_save_vmcoreinfo_init(), which mush run first to ensure vmcoreinfo initialization * is done before regisering with f/w. */ subsys_initcall_sync(setup_fadump); #else /* !CONFIG_PRESERVE_FA_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) { if ((depth != 1) || (strcmp(uname, "ibm,opal") != 0)) return 0; opal_fadump_dt_scan(&fw_dump, node); return 1; } /* * When dump is active but PRESERVE_FA_DUMP is enabled on the kernel, * preserve crash data. The subsequent memory preserving kernel boot * is likely to process this crash data. */ int __init fadump_reserve_mem(void) { if (fw_dump.dump_active) { /* * If last boot has crashed then reserve all the memory * above boot memory to preserve crash data. */ pr_info("Preserving crash data for processing in next boot.\n"); fadump_reserve_crash_area(fw_dump.boot_mem_top); } else pr_debug("FADump-aware kernel..\n"); return 1; } #endif /* CONFIG_PRESERVE_FA_DUMP */ /* Preserve everything above the base address */ static void __init fadump_reserve_crash_area(u64 base) { u64 i, mstart, mend, msize; for_each_mem_range(i, &mstart, &mend) { msize = mend - mstart; if ((mstart + msize) < base) continue; if (mstart < base) { msize -= (base - mstart); mstart = base; } pr_info("Reserving %lluMB of memory at %#016llx for preserving crash data", (msize >> 20), mstart); memblock_reserve(mstart, msize); } } unsigned long __init arch_reserved_kernel_pages(void) { return memblock_reserved_size() / PAGE_SIZE; }