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To support crash hotplug, a mechanism is needed to update the crash elfcorehdr upon CPU or memory changes (eg. hot un/plug or off/ onlining). The crash elfcorehdr describes the CPUs and memory to be written into the vmcore. To track CPU changes, callbacks are registered with the cpuhp mechanism via cpuhp_setup_state_nocalls(CPUHP_BP_PREPARE_DYN). The crash hotplug elfcorehdr update has no explicit ordering requirement (relative to other cpuhp states), so meets the criteria for utilizing CPUHP_BP_PREPARE_DYN. CPUHP_BP_PREPARE_DYN is a dynamic state and avoids the need to introduce a new state for crash hotplug. Also, CPUHP_BP_PREPARE_DYN is the last state in the PREPARE group, just prior to the STARTING group, which is very close to the CPU starting up in a plug/online situation, or stopping in a unplug/ offline situation. This minimizes the window of time during an actual plug/online or unplug/offline situation in which the elfcorehdr would be inaccurate. Note that for a CPU being unplugged or offlined, the CPU will still be present in the list of CPUs generated by crash_prepare_elf64_headers(). However, there is no need to explicitly omit the CPU, see justification in 'crash: change crash_prepare_elf64_headers() to for_each_possible_cpu()'. To track memory changes, a notifier is registered to capture the memblock MEM_ONLINE and MEM_OFFLINE events via register_memory_notifier(). The CPU callbacks and memory notifiers invoke crash_handle_hotplug_event() which performs needed tasks and then dispatches the event to the architecture specific arch_crash_handle_hotplug_event() to update the elfcorehdr with the current state of CPUs and memory. During the process, the kexec_lock is held. Link: https://lkml.kernel.org/r/20230814214446.6659-3-eric.devolder@oracle.com Signed-off-by: Eric DeVolder <eric.devolder@oracle.com> Reviewed-by: Sourabh Jain <sourabhjain@linux.ibm.com> Acked-by: Hari Bathini <hbathini@linux.ibm.com> Acked-by: Baoquan He <bhe@redhat.com> Cc: Akhil Raj <lf32.dev@gmail.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Borislav Petkov (AMD) <bp@alien8.de> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Dave Young <dyoung@redhat.com> Cc: David Hildenbrand <david@redhat.com> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Mimi Zohar <zohar@linux.ibm.com> Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Cc: Sean Christopherson <seanjc@google.com> Cc: Takashi Iwai <tiwai@suse.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Thomas Weißschuh <linux@weissschuh.net> Cc: Valentin Schneider <vschneid@redhat.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
114 lines
4.2 KiB
C
114 lines
4.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef LINUX_CRASH_CORE_H
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#define LINUX_CRASH_CORE_H
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#include <linux/linkage.h>
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#include <linux/elfcore.h>
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#include <linux/elf.h>
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#define CRASH_CORE_NOTE_NAME "CORE"
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#define CRASH_CORE_NOTE_HEAD_BYTES ALIGN(sizeof(struct elf_note), 4)
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#define CRASH_CORE_NOTE_NAME_BYTES ALIGN(sizeof(CRASH_CORE_NOTE_NAME), 4)
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#define CRASH_CORE_NOTE_DESC_BYTES ALIGN(sizeof(struct elf_prstatus), 4)
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/*
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* The per-cpu notes area is a list of notes terminated by a "NULL"
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* note header. For kdump, the code in vmcore.c runs in the context
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* of the second kernel to combine them into one note.
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*/
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#define CRASH_CORE_NOTE_BYTES ((CRASH_CORE_NOTE_HEAD_BYTES * 2) + \
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CRASH_CORE_NOTE_NAME_BYTES + \
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CRASH_CORE_NOTE_DESC_BYTES)
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#define VMCOREINFO_BYTES PAGE_SIZE
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#define VMCOREINFO_NOTE_NAME "VMCOREINFO"
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#define VMCOREINFO_NOTE_NAME_BYTES ALIGN(sizeof(VMCOREINFO_NOTE_NAME), 4)
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#define VMCOREINFO_NOTE_SIZE ((CRASH_CORE_NOTE_HEAD_BYTES * 2) + \
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VMCOREINFO_NOTE_NAME_BYTES + \
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VMCOREINFO_BYTES)
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typedef u32 note_buf_t[CRASH_CORE_NOTE_BYTES/4];
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/* Per cpu memory for storing cpu states in case of system crash. */
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extern note_buf_t __percpu *crash_notes;
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void crash_update_vmcoreinfo_safecopy(void *ptr);
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void crash_save_vmcoreinfo(void);
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void arch_crash_save_vmcoreinfo(void);
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__printf(1, 2)
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void vmcoreinfo_append_str(const char *fmt, ...);
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phys_addr_t paddr_vmcoreinfo_note(void);
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#define VMCOREINFO_OSRELEASE(value) \
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vmcoreinfo_append_str("OSRELEASE=%s\n", value)
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#define VMCOREINFO_BUILD_ID() \
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({ \
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static_assert(sizeof(vmlinux_build_id) == 20); \
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vmcoreinfo_append_str("BUILD-ID=%20phN\n", vmlinux_build_id); \
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})
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#define VMCOREINFO_PAGESIZE(value) \
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vmcoreinfo_append_str("PAGESIZE=%ld\n", value)
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#define VMCOREINFO_SYMBOL(name) \
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vmcoreinfo_append_str("SYMBOL(%s)=%lx\n", #name, (unsigned long)&name)
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#define VMCOREINFO_SYMBOL_ARRAY(name) \
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vmcoreinfo_append_str("SYMBOL(%s)=%lx\n", #name, (unsigned long)name)
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#define VMCOREINFO_SIZE(name) \
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vmcoreinfo_append_str("SIZE(%s)=%lu\n", #name, \
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(unsigned long)sizeof(name))
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#define VMCOREINFO_STRUCT_SIZE(name) \
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vmcoreinfo_append_str("SIZE(%s)=%lu\n", #name, \
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(unsigned long)sizeof(struct name))
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#define VMCOREINFO_OFFSET(name, field) \
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vmcoreinfo_append_str("OFFSET(%s.%s)=%lu\n", #name, #field, \
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(unsigned long)offsetof(struct name, field))
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#define VMCOREINFO_TYPE_OFFSET(name, field) \
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vmcoreinfo_append_str("OFFSET(%s.%s)=%lu\n", #name, #field, \
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(unsigned long)offsetof(name, field))
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#define VMCOREINFO_LENGTH(name, value) \
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vmcoreinfo_append_str("LENGTH(%s)=%lu\n", #name, (unsigned long)value)
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#define VMCOREINFO_NUMBER(name) \
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vmcoreinfo_append_str("NUMBER(%s)=%ld\n", #name, (long)name)
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#define VMCOREINFO_CONFIG(name) \
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vmcoreinfo_append_str("CONFIG_%s=y\n", #name)
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extern unsigned char *vmcoreinfo_data;
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extern size_t vmcoreinfo_size;
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extern u32 *vmcoreinfo_note;
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Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int type,
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void *data, size_t data_len);
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void final_note(Elf_Word *buf);
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int __init parse_crashkernel(char *cmdline, unsigned long long system_ram,
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unsigned long long *crash_size, unsigned long long *crash_base);
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int parse_crashkernel_high(char *cmdline, unsigned long long system_ram,
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unsigned long long *crash_size, unsigned long long *crash_base);
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int parse_crashkernel_low(char *cmdline, unsigned long long system_ram,
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unsigned long long *crash_size, unsigned long long *crash_base);
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/* Alignment required for elf header segment */
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#define ELF_CORE_HEADER_ALIGN 4096
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struct crash_mem {
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unsigned int max_nr_ranges;
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unsigned int nr_ranges;
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struct range ranges[];
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};
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extern int crash_exclude_mem_range(struct crash_mem *mem,
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unsigned long long mstart,
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unsigned long long mend);
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extern int crash_prepare_elf64_headers(struct crash_mem *mem, int need_kernel_map,
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void **addr, unsigned long *sz);
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struct kimage;
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struct kexec_segment;
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#define KEXEC_CRASH_HP_NONE 0
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#define KEXEC_CRASH_HP_ADD_CPU 1
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#define KEXEC_CRASH_HP_REMOVE_CPU 2
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#define KEXEC_CRASH_HP_ADD_MEMORY 3
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#define KEXEC_CRASH_HP_REMOVE_MEMORY 4
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#define KEXEC_CRASH_HP_INVALID_CPU -1U
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#endif /* LINUX_CRASH_CORE_H */
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