This patch set is to allow kdump 2nd kernel to wake up multiple CPUs, a continueing work from: [PATCH v3 0/2] x86, apic, kdump: Disable BSP if boot cpu is AP https://lkml.org/lkml/2013/10/16/300. At v4, basic design has changed. Now users need to figure out initial APIC ID of BSP in the 1st kernel and configures kernel parameter for the 2nd kernel manually using disable_cpu_apicid kernel parameter, which is newly introduced by this patch set. This design is more flexible than the previous version in that we no longer have to rely on ACPI/MP table to get initial APIC ID of BSP. Sorry, this patch set have not include in-source documentation requested by Borislav Petkov yet, but I'll post it later separately, which would be better to focus on documentation reviewing. ChangeLog v6 => v7) - Rebased on top of v3.13-rc1 - Remove a patch that cleans up the code around x86_cpu_physical_apicid. Instead, use read_apic_id() directly in generic_processor_info(). The clean up removed here will be done in different patch set. v5 => v6) - Remove use of rdmsr(IA32_APIC_BASE) to initialize bsp_physical_apicid since the MSR doesn't work well on some cluster systems, suggested by HPA. Also, current users of the variable expects the initial apicid reported through MP table only; removing the use of the MSR is not problematic. - Rename bsp_physical_apicid as bios_bsp_physical_apicid to make it clear that the apidid contained there is the one reported from some BIOS table. Also, initialize it not only by MP table but also by ACPI MADT. - Change message displayed when specified cpu is disabled from: ACPI: Disable specified CPU. Processor 0/0x0 ignored. to: ACPI: Disabling requested cpu. Processor 0/0x0 ignored. v4 => v5) - Rebased on top of v3.12 - Introduce bsp_physical_apicid that has the initial APIC ID for the processor with BSP flag on IA32_APIC_BASE MSR. Without this, boot_cpu_physical_apicid has temporarilly the value around MP table related codes, although it's designed to have the initial APIC ID for the processor that is doing the boot up. Use the bsp_physical_apicid in MP table related codes; no impact on semantics at runtime there. v3 => v4) - Rebased on top of v3.12-rc6 - Basic design has been changed. Now users need to figure out initial APIC ID of BSP in the 1st kernel and configures kernel parameter for the 2nd kernel manually using disable_cpu_apic kernel parameter to be newly introduced in this patch set. This design is more flexible than the previous version in that we no longer have to rely on ACPI/MP table to get initial APIC ID of BSP. v2 => v3) - Change default value of boot_cpu_is_bsp to true. - Before executing rdmsr(MSR_IA32_APICBASE), check if the number of processor family is larger than or equal to 6 in order to avoid invalid opcode exception on processors where MSR_IA32_APICBASE is not supported. v1 => v2) - Rebased on top of v3.12-rc5. - Fix linking time error of boot_cpu_is_bsp_init() in case of CONFIG_LOCAL_APIC disabled by adding empty static inline function instead. - Fix missing feature check by means of cpu_has_apic macro in boot_cpu_is_bsp_init() before calling rdmsr_safe(MSR_IA32_APICBASE). NOTE: I've checked local apic-present case only; I don't have any x86 processor without local apic. - Add __init annotation to boot_cpu_is_bsp_init(). Test - built with and without CONFIG_LOCAL_APIC - tested x86_64 in case of acpi and MP table - tested disable_cpu_apicid=<n> to disable both AP and BSP --- HATAYAMA Daisuke (2): x86, apic: Add disable_cpu_apicid kernel parameter Documentation, x86, apic, kexec: Add disable_cpu_apicid kernel parameter Documentation/kernel-parameters.txt | 9 ++++++ arch/x86/kernel/apic/apic.c | 49 +++++++++++++++++++++++++++++++++++ 2 files changed, 58 insertions(+) -- Thanks. HATAYAMA, Daisuke
