This version includes the work done by Brian Gerst (https://lore.kernel.org/all/20230222221301.245890-1-brgerst@xxxxxxxxx/) to remove the global variables initial_gs, initial_stack, and early_gdt_descr from the 64-bit boot code. The first 2 patches have been squashed with patch 6, while the last 4 patches for removing the global variables and simplifying boot setup are added on top of the series. Thanks, Usama Changes across versions: v2: Cut it back to just INIT/SIPI/SIPI in parallel for now, nothing more v3: Clean up x2apic patch, add MTRR optimisation, lock topology update in preparation for more parallelisation. v4: Fixes to the real mode parallelisation patch spotted by SeanC, to avoid scribbling on initial_gs in common_cpu_up(), and to allow all 24 bits of the physical X2APIC ID to be used. That patch still needs a Signed-off-by from its original author, who once claimed not to remember writing it at all. But now we've fixed it, hopefully he'll admit it now :) v5: rebase to v6.1 and remeasure performance, disable parallel bringup for AMD CPUs. v6: rebase to v6.2-rc6, disabled parallel boot on amd as a cpu bug and reused timer calibration for secondary CPUs. v7: [David Woodhouse] iterate over all possible CPUs to find any existing cluster mask in alloc_clustermask. (patch 1/9) Keep parallel AMD support enabled in AMD, using APIC ID in CPUID leaf 0x0B (for x2APIC mode) or CPUID leaf 0x01 where 8 bits are sufficient. Included sanity checks for APIC id from 0x0B. (patch 6/9) Removed patch for reusing timer calibration for secondary CPUs. commit message and code improvements. v8: Fix CPU0 hotplug by setting up the initial_gs, initial_stack and early_gdt_descr. Drop trampoline lock and bail if APIC ID not found in find_cpunr. Code comments improved and debug prints added. v9: Drop patch to avoid repeated saves of MTRR at boot time. rebased and retested at v6.2-rc8. added kernel doc for no_parallel_bringup and made do_parallel_bringup __ro_after_init. v10: Fixed suspend/resume not working with parallel smpboot. rebased and retested to 6.2. fixed checkpatch errors. v11: Added patches from Brian Gerst to remove the global variables initial_gs, initial_stack, and early_gdt_descr from the 64-bit boot code (https://lore.kernel.org/all/20230222221301.245890-1-brgerst@xxxxxxxxx/). Brian Gerst (4): x86/smpboot: Remove initial_stack on 64-bit x86/smpboot: Remove early_gdt_descr on 64-bit x86/smpboot: Remove initial_gs x86/smpboot: Simplify boot CPU setup David Woodhouse (8): x86/apic/x2apic: Allow CPU cluster_mask to be populated in parallel cpu/hotplug: Move idle_thread_get() to <linux/smpboot.h> cpu/hotplug: Add dynamic parallel bringup states before CPUHP_BRINGUP_CPU x86/smpboot: Reference count on smpboot_setup_warm_reset_vector() x86/smpboot: Split up native_cpu_up into separate phases and document them x86/smpboot: Support parallel startup of secondary CPUs x86/smpboot: Send INIT/SIPI/SIPI to secondary CPUs in parallel x86/smpboot: Serialize topology updates for secondary bringup .../admin-guide/kernel-parameters.txt | 3 + arch/x86/include/asm/processor.h | 6 +- arch/x86/include/asm/realmode.h | 4 +- arch/x86/include/asm/smp.h | 13 +- arch/x86/include/asm/topology.h | 2 - arch/x86/kernel/acpi/sleep.c | 12 +- arch/x86/kernel/apic/apic.c | 2 +- arch/x86/kernel/apic/x2apic_cluster.c | 126 ++++--- arch/x86/kernel/asm-offsets.c | 1 + arch/x86/kernel/cpu/common.c | 6 +- arch/x86/kernel/head_64.S | 125 +++++-- arch/x86/kernel/smpboot.c | 350 +++++++++++++----- arch/x86/realmode/init.c | 3 + arch/x86/realmode/rm/trampoline_64.S | 14 + arch/x86/xen/smp_pv.c | 4 +- arch/x86/xen/xen-head.S | 2 +- include/linux/cpuhotplug.h | 2 + include/linux/smpboot.h | 7 + kernel/cpu.c | 31 +- kernel/smpboot.h | 2 - 20 files changed, 525 insertions(+), 190 deletions(-) -- 2.25.1