// SPDX-License-Identifier: GPL-2.0-only /* * 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 <vgoyal@redhat.com> * */ #define pr_fmt(fmt) "kexec: " fmt #include <linux/types.h> #include <linux/kernel.h> #include <linux/smp.h> #include <linux/reboot.h> #include <linux/kexec.h> #include <linux/delay.h> #include <linux/elf.h> #include <linux/elfcore.h> #include <linux/export.h> #include <linux/slab.h> #include <linux/vmalloc.h> #include <linux/memblock.h> #include <asm/processor.h> #include <asm/hardirq.h> #include <asm/nmi.h> #include <asm/hw_irq.h> #include <asm/apic.h> #include <asm/e820/types.h> #include <asm/io_apic.h> #include <asm/hpet.h> #include <linux/kdebug.h> #include <asm/cpu.h> #include <asm/reboot.h> #include <asm/virtext.h> #include <asm/intel_pt.h> #include <asm/crash.h> #include <asm/cmdline.h> /* 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); 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) { 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(); clear_IO_APIC(); #endif lapic_shutdown(); restore_boot_irq_mode(); #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(struct resource *res, void *arg) { unsigned int *nr_ranges = arg; (*nr_ranges)++; return 0; } /* Gather all the required information to prepare elf headers for ram regions */ static struct crash_mem *fill_up_crash_elf_data(void) { unsigned int nr_ranges = 0; struct crash_mem *cmem; walk_system_ram_res(0, -1, &nr_ranges, get_nr_ram_ranges_callback); if (!nr_ranges) return NULL; /* * Exclusion of crash region and/or crashk_low_res may cause * another range split. So add extra two slots here. */ nr_ranges += 2; cmem = vzalloc(struct_size(cmem, ranges, nr_ranges)); if (!cmem) return NULL; cmem->max_nr_ranges = nr_ranges; cmem->nr_ranges = 0; return cmem; } /* * Look for any unwanted ranges between mstart, mend and remove them. This * might lead to split and split ranges are put in cmem->ranges[] array */ static int elf_header_exclude_ranges(struct crash_mem *cmem) { int ret = 0; /* Exclude the low 1M because it is always reserved */ ret = crash_exclude_mem_range(cmem, 0, (1<<20)-1); if (ret) return ret; /* Exclude crashkernel region */ ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end); if (ret) return ret; if (crashk_low_res.end) ret = crash_exclude_mem_range(cmem, crashk_low_res.start, crashk_low_res.end); return ret; } static int prepare_elf64_ram_headers_callback(struct resource *res, void *arg) { struct crash_mem *cmem = arg; cmem->ranges[cmem->nr_ranges].start = res->start; cmem->ranges[cmem->nr_ranges].end = res->end; cmem->nr_ranges++; return 0; } /* Prepare elf headers. Return addr and size */ static int prepare_elf_headers(struct kimage *image, void **addr, unsigned long *sz) { struct crash_mem *cmem; int ret; cmem = fill_up_crash_elf_data(); if (!cmem) return -ENOMEM; ret = walk_system_ram_res(0, -1, cmem, prepare_elf64_ram_headers_callback); if (ret) goto out; /* Exclude unwanted mem ranges */ ret = elf_header_exclude_ranges(cmem); if (ret) goto out; /* By default prepare 64bit headers */ ret = crash_prepare_elf64_headers(cmem, IS_ENABLED(CONFIG_X86_64), addr, sz); out: vfree(cmem); return ret; } static int add_e820_entry(struct boot_params *params, struct e820_entry *entry) { unsigned int nr_e820_entries; nr_e820_entries = params->e820_entries; if (nr_e820_entries >= E820_MAX_ENTRIES_ZEROPAGE) return 1; memcpy(¶ms->e820_table[nr_e820_entries], entry, sizeof(struct e820_entry)); params->e820_entries++; return 0; } static int memmap_entry_callback(struct resource *res, void *arg) { struct crash_memmap_data *cmd = arg; struct boot_params *params = cmd->params; struct e820_entry ei; ei.addr = res->start; ei.size = resource_size(res); 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; cmem->ranges[0].start = mstart; cmem->ranges[0].end = mend; cmem->nr_ranges = 1; /* Exclude elf header region */ start = image->elf_load_addr; end = start + image->elf_headers_sz - 1; return crash_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 e820_entry ei; struct crash_memmap_data cmd; struct crash_mem *cmem; cmem = vzalloc(struct_size(cmem, ranges, 1)); if (!cmem) return -ENOMEM; memset(&cmd, 0, sizeof(struct crash_memmap_data)); cmd.params = params; /* Add the low 1M */ cmd.type = E820_TYPE_RAM; flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY; walk_iomem_res_desc(IORES_DESC_NONE, flags, 0, (1<<20)-1, &cmd, memmap_entry_callback); /* Add ACPI tables */ cmd.type = E820_TYPE_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_TYPE_NVS; walk_iomem_res_desc(IORES_DESC_ACPI_NV_STORAGE, flags, 0, -1, &cmd, memmap_entry_callback); /* Add e820 reserved ranges */ cmd.type = E820_TYPE_RESERVED; flags = IORESOURCE_MEM; walk_iomem_res_desc(IORES_DESC_RESERVED, 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 = resource_size(&crashk_low_res); ei.type = E820_TYPE_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_TYPE_RAM; add_e820_entry(params, &ei); } out: vfree(cmem); return ret; } 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 }; /* Prepare elf headers and add a segment */ ret = prepare_elf_headers(image, &kbuf.buffer, &kbuf.bufsz); if (ret) return ret; image->elf_headers = kbuf.buffer; image->elf_headers_sz = kbuf.bufsz; kbuf.memsz = kbuf.bufsz; kbuf.buf_align = ELF_CORE_HEADER_ALIGN; kbuf.mem = KEXEC_BUF_MEM_UNKNOWN; ret = kexec_add_buffer(&kbuf); if (ret) { vfree((void *)image->elf_headers); return ret; } image->elf_load_addr = kbuf.mem; pr_debug("Loaded ELF headers at 0x%lx bufsz=0x%lx memsz=0x%lx\n", image->elf_load_addr, kbuf.bufsz, kbuf.bufsz); return ret; } #endif /* CONFIG_KEXEC_FILE */