/* * Architecture specific (i386/x86_64) functions for kexec based crash dumps. * * Created by: Hariprasad Nellitheertha (hari@in.ibm.com) * * Copyright (C) IBM Corporation, 2004. All rights reserved. * Copyright (C) Red Hat Inc., 2014. All rights reserved. * Authors: * Vivek Goyal * */ #define pr_fmt(fmt) "kexec: " fmt #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* Alignment required for elf header segment */ #define ELF_CORE_HEADER_ALIGN 4096 /* This primarily represents number of split ranges due to exclusion */ #define CRASH_MAX_RANGES 16 struct crash_mem_range { u64 start, end; }; struct crash_mem { unsigned int nr_ranges; struct crash_mem_range ranges[CRASH_MAX_RANGES]; }; /* Misc data about ram ranges needed to prepare elf headers */ struct crash_elf_data { struct kimage *image; /* * Total number of ram ranges we have after various adjustments for * crash reserved region, etc. */ unsigned int max_nr_ranges; /* Pointer to elf header */ void *ehdr; /* Pointer to next phdr */ void *bufp; struct crash_mem mem; }; /* Used while preparing memory map entries for second kernel */ struct crash_memmap_data { struct boot_params *params; /* Type of memory */ unsigned int type; }; /* * This is used to VMCLEAR all VMCSs loaded on the * processor. And when loading kvm_intel module, the * callback function pointer will be assigned. * * protected by rcu. */ crash_vmclear_fn __rcu *crash_vmclear_loaded_vmcss = NULL; EXPORT_SYMBOL_GPL(crash_vmclear_loaded_vmcss); unsigned long crash_zero_bytes; static inline void cpu_crash_vmclear_loaded_vmcss(void) { crash_vmclear_fn *do_vmclear_operation = NULL; rcu_read_lock(); do_vmclear_operation = rcu_dereference(crash_vmclear_loaded_vmcss); if (do_vmclear_operation) do_vmclear_operation(); rcu_read_unlock(); } #if defined(CONFIG_SMP) && defined(CONFIG_X86_LOCAL_APIC) static void kdump_nmi_callback(int cpu, struct pt_regs *regs) { #ifdef CONFIG_X86_32 struct pt_regs fixed_regs; if (!user_mode(regs)) { crash_fixup_ss_esp(&fixed_regs, regs); regs = &fixed_regs; } #endif crash_save_cpu(regs, cpu); /* * VMCLEAR VMCSs loaded on all cpus if needed. */ cpu_crash_vmclear_loaded_vmcss(); /* Disable VMX or SVM if needed. * * We need to disable virtualization on all CPUs. * Having VMX or SVM enabled on any CPU may break rebooting * after the kdump kernel has finished its task. */ cpu_emergency_vmxoff(); cpu_emergency_svm_disable(); /* * Disable Intel PT to stop its logging */ cpu_emergency_stop_pt(); disable_local_APIC(); } void kdump_nmi_shootdown_cpus(void) { nmi_shootdown_cpus(kdump_nmi_callback); disable_local_APIC(); } /* Override the weak function in kernel/panic.c */ void crash_smp_send_stop(void) { static int cpus_stopped; if (cpus_stopped) return; if (smp_ops.crash_stop_other_cpus) smp_ops.crash_stop_other_cpus(); else smp_send_stop(); cpus_stopped = 1; } #else void crash_smp_send_stop(void) { /* There are no cpus to shootdown */ } #endif void native_machine_crash_shutdown(struct pt_regs *regs) { /* This function is only called after the system * has panicked or is otherwise in a critical state. * The minimum amount of code to allow a kexec'd kernel * to run successfully needs to happen here. * * In practice this means shooting down the other cpus in * an SMP system. */ /* The kernel is broken so disable interrupts */ local_irq_disable(); crash_smp_send_stop(); /* * VMCLEAR VMCSs loaded on this cpu if needed. */ cpu_crash_vmclear_loaded_vmcss(); /* Booting kdump kernel with VMX or SVM enabled won't work, * because (among other limitations) we can't disable paging * with the virt flags. */ cpu_emergency_vmxoff(); cpu_emergency_svm_disable(); /* * Disable Intel PT to stop its logging */ cpu_emergency_stop_pt(); #ifdef CONFIG_X86_IO_APIC /* Prevent crash_kexec() from deadlocking on ioapic_lock. */ ioapic_zap_locks(); disable_IO_APIC(); #endif lapic_shutdown(); #ifdef CONFIG_HPET_TIMER hpet_disable(); #endif crash_save_cpu(regs, safe_smp_processor_id()); } #ifdef CONFIG_KEXEC_FILE static int get_nr_ram_ranges_callback(u64 start, u64 end, void *arg) { unsigned int *nr_ranges = arg; (*nr_ranges)++; return 0; } /* Gather all the required information to prepare elf headers for ram regions */ static void fill_up_crash_elf_data(struct crash_elf_data *ced, struct kimage *image) { unsigned int nr_ranges = 0; ced->image = image; walk_system_ram_res(0, -1, &nr_ranges, get_nr_ram_ranges_callback); ced->max_nr_ranges = nr_ranges; /* Exclusion of crash region could split memory ranges */ ced->max_nr_ranges++; /* If crashk_low_res is not 0, another range split possible */ if (crashk_low_res.end) ced->max_nr_ranges++; } static int exclude_mem_range(struct crash_mem *mem, unsigned long long mstart, unsigned long long mend) { int i, j; unsigned long long start, end; struct crash_mem_range temp_range = {0, 0}; for (i = 0; i < mem->nr_ranges; i++) { start = mem->ranges[i].start; end = mem->ranges[i].end; if (mstart > end || mend < start) continue; /* Truncate any area outside of range */ if (mstart < start) mstart = start; if (mend > end) mend = end; /* Found completely overlapping range */ if (mstart == start && mend == end) { mem->ranges[i].start = 0; mem->ranges[i].end = 0; if (i < mem->nr_ranges - 1) { /* Shift rest of the ranges to left */ for (j = i; j < mem->nr_ranges - 1; j++) { mem->ranges[j].start = mem->ranges[j+1].start; mem->ranges[j].end = mem->ranges[j+1].end; } } mem->nr_ranges--; return 0; } if (mstart > start && mend < end) { /* Split original range */ mem->ranges[i].end = mstart - 1; temp_range.start = mend + 1; temp_range.end = end; } else if (mstart != start) mem->ranges[i].end = mstart - 1; else mem->ranges[i].start = mend + 1; break; } /* If a split happend, add the split to array */ if (!temp_range.end) return 0; /* Split happened */ if (i == CRASH_MAX_RANGES - 1) { pr_err("Too many crash ranges after split\n"); return -ENOMEM; } /* Location where new range should go */ j = i + 1; if (j < mem->nr_ranges) { /* Move over all ranges one slot towards the end */ for (i = mem->nr_ranges - 1; i >= j; i--) mem->ranges[i + 1] = mem->ranges[i]; } mem->ranges[j].start = temp_range.start; mem->ranges[j].end = temp_range.end; mem->nr_ranges++; return 0; } /* * Look for any unwanted ranges between mstart, mend and remove them. This * might lead to split and split ranges are put in ced->mem.ranges[] array */ static int elf_header_exclude_ranges(struct crash_elf_data *ced, unsigned long long mstart, unsigned long long mend) { struct crash_mem *cmem = &ced->mem; int ret = 0; memset(cmem->ranges, 0, sizeof(cmem->ranges)); cmem->ranges[0].start = mstart; cmem->ranges[0].end = mend; cmem->nr_ranges = 1; /* Exclude crashkernel region */ ret = exclude_mem_range(cmem, crashk_res.start, crashk_res.end); if (ret) return ret; if (crashk_low_res.end) { ret = exclude_mem_range(cmem, crashk_low_res.start, crashk_low_res.end); if (ret) return ret; } return ret; } static int prepare_elf64_ram_headers_callback(u64 start, u64 end, void *arg) { struct crash_elf_data *ced = arg; Elf64_Ehdr *ehdr; Elf64_Phdr *phdr; unsigned long mstart, mend; struct kimage *image = ced->image; struct crash_mem *cmem; int ret, i; ehdr = ced->ehdr; /* Exclude unwanted mem ranges */ ret = elf_header_exclude_ranges(ced, start, end); if (ret) return ret; /* Go through all the ranges in ced->mem.ranges[] and prepare phdr */ cmem = &ced->mem; for (i = 0; i < cmem->nr_ranges; i++) { mstart = cmem->ranges[i].start; mend = cmem->ranges[i].end; phdr = ced->bufp; ced->bufp += sizeof(Elf64_Phdr); phdr->p_type = PT_LOAD; phdr->p_flags = PF_R|PF_W|PF_X; phdr->p_offset = mstart; /* * If a range matches backup region, adjust offset to backup * segment. */ if (mstart == image->arch.backup_src_start && (mend - mstart + 1) == image->arch.backup_src_sz) phdr->p_offset = image->arch.backup_load_addr; phdr->p_paddr = mstart; phdr->p_vaddr = (unsigned long long) __va(mstart); phdr->p_filesz = phdr->p_memsz = mend - mstart + 1; phdr->p_align = 0; ehdr->e_phnum++; pr_debug("Crash PT_LOAD elf header. phdr=%p vaddr=0x%llx, paddr=0x%llx, sz=0x%llx e_phnum=%d p_offset=0x%llx\n", phdr, phdr->p_vaddr, phdr->p_paddr, phdr->p_filesz, ehdr->e_phnum, phdr->p_offset); } return ret; } static int prepare_elf64_headers(struct crash_elf_data *ced, void **addr, unsigned long *sz) { Elf64_Ehdr *ehdr; Elf64_Phdr *phdr; unsigned long nr_cpus = num_possible_cpus(), nr_phdr, elf_sz; unsigned char *buf, *bufp; unsigned int cpu; unsigned long long notes_addr; int ret; /* extra phdr for vmcoreinfo elf note */ nr_phdr = nr_cpus + 1; nr_phdr += ced->max_nr_ranges; /* * kexec-tools creates an extra PT_LOAD phdr for kernel text mapping * area on x86_64 (ffffffff80000000 - ffffffffa0000000). * I think this is required by tools like gdb. So same physical * memory will be mapped in two elf headers. One will contain kernel * text virtual addresses and other will have __va(physical) addresses. */ nr_phdr++; elf_sz = sizeof(Elf64_Ehdr) + nr_phdr * sizeof(Elf64_Phdr); elf_sz = ALIGN(elf_sz, ELF_CORE_HEADER_ALIGN); buf = vzalloc(elf_sz); if (!buf) return -ENOMEM; bufp = buf; ehdr = (Elf64_Ehdr *)bufp; bufp += sizeof(Elf64_Ehdr); memcpy(ehdr->e_ident, ELFMAG, SELFMAG); ehdr->e_ident[EI_CLASS] = ELFCLASS64; ehdr->e_ident[EI_DATA] = ELFDATA2LSB; ehdr->e_ident[EI_VERSION] = EV_CURRENT; ehdr->e_ident[EI_OSABI] = ELF_OSABI; memset(ehdr->e_ident + EI_PAD, 0, EI_NIDENT - EI_PAD); ehdr->e_type = ET_CORE; ehdr->e_machine = ELF_ARCH; ehdr->e_version = EV_CURRENT; ehdr->e_phoff = sizeof(Elf64_Ehdr); ehdr->e_ehsize = sizeof(Elf64_Ehdr); ehdr->e_phentsize = sizeof(Elf64_Phdr); /* Prepare one phdr of type PT_NOTE for each present cpu */ for_each_present_cpu(cpu) { phdr = (Elf64_Phdr *)bufp; bufp += sizeof(Elf64_Phdr); phdr->p_type = PT_NOTE; notes_addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpu)); phdr->p_offset = phdr->p_paddr = notes_addr; phdr->p_filesz = phdr->p_memsz = sizeof(note_buf_t); (ehdr->e_phnum)++; } /* Prepare one PT_NOTE header for vmcoreinfo */ phdr = (Elf64_Phdr *)bufp; bufp += sizeof(Elf64_Phdr); phdr->p_type = PT_NOTE; phdr->p_offset = phdr->p_paddr = paddr_vmcoreinfo_note(); phdr->p_filesz = phdr->p_memsz = sizeof(vmcoreinfo_note); (ehdr->e_phnum)++; #ifdef CONFIG_X86_64 /* Prepare PT_LOAD type program header for kernel text region */ phdr = (Elf64_Phdr *)bufp; bufp += sizeof(Elf64_Phdr); phdr->p_type = PT_LOAD; phdr->p_flags = PF_R|PF_W|PF_X; phdr->p_vaddr = (Elf64_Addr)_text; phdr->p_filesz = phdr->p_memsz = _end - _text; phdr->p_offset = phdr->p_paddr = __pa_symbol(_text); (ehdr->e_phnum)++; #endif /* Prepare PT_LOAD headers for system ram chunks. */ ced->ehdr = ehdr; ced->bufp = bufp; ret = walk_system_ram_res(0, -1, ced, prepare_elf64_ram_headers_callback); if (ret < 0) return ret; *addr = buf; *sz = elf_sz; return 0; } /* Prepare elf headers. Return addr and size */ static int prepare_elf_headers(struct kimage *image, void **addr, unsigned long *sz) { struct crash_elf_data *ced; int ret; ced = kzalloc(sizeof(*ced), GFP_KERNEL); if (!ced) return -ENOMEM; fill_up_crash_elf_data(ced, image); /* By default prepare 64bit headers */ ret = prepare_elf64_headers(ced, addr, sz); kfree(ced); return ret; } static int add_e820_entry(struct boot_params *params, struct e820entry *entry) { unsigned int nr_e820_entries; nr_e820_entries = params->e820_entries; if (nr_e820_entries >= E820MAX) return 1; memcpy(¶ms->e820_map[nr_e820_entries], entry, sizeof(struct e820entry)); params->e820_entries++; return 0; } static int memmap_entry_callback(u64 start, u64 end, void *arg) { struct crash_memmap_data *cmd = arg; struct boot_params *params = cmd->params; struct e820entry ei; ei.addr = start; ei.size = end - start + 1; ei.type = cmd->type; add_e820_entry(params, &ei); return 0; } static int memmap_exclude_ranges(struct kimage *image, struct crash_mem *cmem, unsigned long long mstart, unsigned long long mend) { unsigned long start, end; int ret = 0; cmem->ranges[0].start = mstart; cmem->ranges[0].end = mend; cmem->nr_ranges = 1; /* Exclude Backup region */ start = image->arch.backup_load_addr; end = start + image->arch.backup_src_sz - 1; ret = exclude_mem_range(cmem, start, end); if (ret) return ret; /* Exclude elf header region */ start = image->arch.elf_load_addr; end = start + image->arch.elf_headers_sz - 1; return exclude_mem_range(cmem, start, end); } /* Prepare memory map for crash dump kernel */ int crash_setup_memmap_entries(struct kimage *image, struct boot_params *params) { int i, ret = 0; unsigned long flags; struct e820entry ei; struct crash_memmap_data cmd; struct crash_mem *cmem; cmem = vzalloc(sizeof(struct crash_mem)); if (!cmem) return -ENOMEM; memset(&cmd, 0, sizeof(struct crash_memmap_data)); cmd.params = params; /* Add first 640K segment */ ei.addr = image->arch.backup_src_start; ei.size = image->arch.backup_src_sz; ei.type = E820_RAM; add_e820_entry(params, &ei); /* Add ACPI tables */ cmd.type = E820_ACPI; flags = IORESOURCE_MEM | IORESOURCE_BUSY; walk_iomem_res_desc(IORES_DESC_ACPI_TABLES, flags, 0, -1, &cmd, memmap_entry_callback); /* Add ACPI Non-volatile Storage */ cmd.type = E820_NVS; walk_iomem_res_desc(IORES_DESC_ACPI_NV_STORAGE, flags, 0, -1, &cmd, memmap_entry_callback); /* Add crashk_low_res region */ if (crashk_low_res.end) { ei.addr = crashk_low_res.start; ei.size = crashk_low_res.end - crashk_low_res.start + 1; ei.type = E820_RAM; add_e820_entry(params, &ei); } /* Exclude some ranges from crashk_res and add rest to memmap */ ret = memmap_exclude_ranges(image, cmem, crashk_res.start, crashk_res.end); if (ret) goto out; for (i = 0; i < cmem->nr_ranges; i++) { ei.size = cmem->ranges[i].end - cmem->ranges[i].start + 1; /* If entry is less than a page, skip it */ if (ei.size < PAGE_SIZE) continue; ei.addr = cmem->ranges[i].start; ei.type = E820_RAM; add_e820_entry(params, &ei); } out: vfree(cmem); return ret; } static int determine_backup_region(u64 start, u64 end, void *arg) { struct kimage *image = arg; image->arch.backup_src_start = start; image->arch.backup_src_sz = end - start + 1; /* Expecting only one range for backup region */ return 1; } int crash_load_segments(struct kimage *image) { int ret; struct kexec_buf kbuf = { .image = image, .buf_min = 0, .buf_max = ULONG_MAX, .top_down = false }; /* * Determine and load a segment for backup area. First 640K RAM * region is backup source */ ret = walk_system_ram_res(KEXEC_BACKUP_SRC_START, KEXEC_BACKUP_SRC_END, image, determine_backup_region); /* Zero or postive return values are ok */ if (ret < 0) return ret; /* Add backup segment. */ if (image->arch.backup_src_sz) { kbuf.buffer = &crash_zero_bytes; kbuf.bufsz = sizeof(crash_zero_bytes); kbuf.memsz = image->arch.backup_src_sz; kbuf.buf_align = PAGE_SIZE; /* * Ideally there is no source for backup segment. This is * copied in purgatory after crash. Just add a zero filled * segment for now to make sure checksum logic works fine. */ ret = kexec_add_buffer(&kbuf); if (ret) return ret; image->arch.backup_load_addr = kbuf.mem; pr_debug("Loaded backup region at 0x%lx backup_start=0x%lx memsz=0x%lx\n", image->arch.backup_load_addr, image->arch.backup_src_start, kbuf.memsz); } /* Prepare elf headers and add a segment */ ret = prepare_elf_headers(image, &kbuf.buffer, &kbuf.bufsz); if (ret) return ret; image->arch.elf_headers = kbuf.buffer; image->arch.elf_headers_sz = kbuf.bufsz; kbuf.memsz = kbuf.bufsz; kbuf.buf_align = ELF_CORE_HEADER_ALIGN; ret = kexec_add_buffer(&kbuf); if (ret) { vfree((void *)image->arch.elf_headers); return ret; } image->arch.elf_load_addr = kbuf.mem; pr_debug("Loaded ELF headers at 0x%lx bufsz=0x%lx memsz=0x%lx\n", image->arch.elf_load_addr, kbuf.bufsz, kbuf.bufsz); return ret; } #endif /* CONFIG_KEXEC_FILE */