// SPDX-License-Identifier: GPL-2.0-only /* * crash.c - kernel crash support code. * Copyright (C) 2002-2004 Eric Biederman <[email protected]> */ #define pr_fmt(fmt) … #include <linux/buildid.h> #include <linux/init.h> #include <linux/utsname.h> #include <linux/vmalloc.h> #include <linux/sizes.h> #include <linux/kexec.h> #include <linux/memory.h> #include <linux/mm.h> #include <linux/cpuhotplug.h> #include <linux/memblock.h> #include <linux/kmemleak.h> #include <linux/crash_core.h> #include <linux/reboot.h> #include <linux/btf.h> #include <linux/objtool.h> #include <asm/page.h> #include <asm/sections.h> #include <crypto/sha1.h> #include "kallsyms_internal.h" #include "kexec_internal.h" /* Per cpu memory for storing cpu states in case of system crash. */ note_buf_t __percpu *crash_notes; #ifdef CONFIG_CRASH_DUMP int kimage_crash_copy_vmcoreinfo(struct kimage *image) { … } int kexec_should_crash(struct task_struct *p) { … } int kexec_crash_loaded(void) { … } EXPORT_SYMBOL_GPL(…); /* * No panic_cpu check version of crash_kexec(). This function is called * only when panic_cpu holds the current CPU number; this is the only CPU * which processes crash_kexec routines. */ void __noclone __crash_kexec(struct pt_regs *regs) { … } STACK_FRAME_NON_STANDARD(…); __bpf_kfunc void crash_kexec(struct pt_regs *regs) { … } static inline resource_size_t crash_resource_size(const struct resource *res) { … } int crash_prepare_elf64_headers(struct crash_mem *mem, int need_kernel_map, void **addr, unsigned long *sz) { … } int crash_exclude_mem_range(struct crash_mem *mem, unsigned long long mstart, unsigned long long mend) { … } ssize_t crash_get_memory_size(void) { … } static int __crash_shrink_memory(struct resource *old_res, unsigned long new_size) { … } int crash_shrink_memory(unsigned long new_size) { … } void crash_save_cpu(struct pt_regs *regs, int cpu) { … } static int __init crash_notes_memory_init(void) { … } subsys_initcall(crash_notes_memory_init); #endif /*CONFIG_CRASH_DUMP*/ #ifdef CONFIG_CRASH_HOTPLUG #undef pr_fmt #define pr_fmt(fmt) … /* * Different than kexec/kdump loading/unloading/jumping/shrinking which * usually rarely happen, there will be many crash hotplug events notified * during one short period, e.g one memory board is hot added and memory * regions are online. So mutex lock __crash_hotplug_lock is used to * serialize the crash hotplug handling specifically. */ static DEFINE_MUTEX(__crash_hotplug_lock); #define crash_hotplug_lock() … #define crash_hotplug_unlock() … /* * This routine utilized when the crash_hotplug sysfs node is read. * It reflects the kernel's ability/permission to update the kdump * image directly. */ int crash_check_hotplug_support(void) { … } /* * To accurately reflect hot un/plug changes of CPU and Memory resources * (including onling and offlining of those resources), the relevant * kexec segments must be updated with latest CPU and Memory resources. * * Architectures must ensure two things for all segments that need * updating during hotplug events: * * 1. Segments must be large enough to accommodate a growing number of * resources. * 2. Exclude the segments from SHA verification. * * For example, on most architectures, the elfcorehdr (which is passed * to the crash kernel via the elfcorehdr= parameter) must include the * new list of CPUs and memory. To make changes to the elfcorehdr, it * should be large enough to permit a growing number of CPU and Memory * resources. One can estimate the elfcorehdr memory size based on * NR_CPUS_DEFAULT and CRASH_MAX_MEMORY_RANGES. The elfcorehdr is * excluded from SHA verification by default if the architecture * supports crash hotplug. */ static void crash_handle_hotplug_event(unsigned int hp_action, unsigned int cpu, void *arg) { … } static int crash_memhp_notifier(struct notifier_block *nb, unsigned long val, void *arg) { … } static struct notifier_block crash_memhp_nb = …; static int crash_cpuhp_online(unsigned int cpu) { … } static int crash_cpuhp_offline(unsigned int cpu) { … } static int __init crash_hotplug_init(void) { … } subsys_initcall(crash_hotplug_init); #endif
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