[PATCH v11 00/12] Parallel CPU bringup for x86_64

[Usama Arif]

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