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    Subject[tip:x86/acpi] x86/acpi: Restore the order of CPU IDs
    Commit-ID:  2b85b3d22920db7473e5fed5719e7955c0ec323e
    Gitweb: http://git.kernel.org/tip/2b85b3d22920db7473e5fed5719e7955c0ec323e
    Author: Dou Liyang <douly.fnst@cn.fujitsu.com>
    AuthorDate: Fri, 3 Mar 2017 16:02:25 +0800
    Committer: Thomas Gleixner <tglx@linutronix.de>
    CommitDate: Sat, 11 Mar 2017 14:41:19 +0100

    x86/acpi: Restore the order of CPU IDs

    The following commits:

    f7c28833c2 ("x86/acpi: Enable acpi to register all possible cpus at
    boot time") and 8f54969dc8 ("x86/acpi: Introduce persistent storage
    for cpuid <-> apicid mapping")

    ... registered all the possible CPUs at boot time via ACPI tables to
    make the mapping of cpuid <-> apicid fixed. Both enabled and disabled
    CPUs could have a logical CPU ID after boot time.

    But, ACPI tables are unreliable. the number amd order of Local APIC
    entries which depends on the firmware is often inconsistent with the
    physical devices. Even if they are consistent, The disabled CPUs which
    take up some logical CPU IDs will also make the order discontinuous.

    Revert the part of disabled CPUs registration, keep the allocation
    logic of logical CPU IDs and also keep some code location changes.

    Signed-off-by: Dou Liyang <douly.fnst@cn.fujitsu.com>
    Tested-by: Xiaolong Ye <xiaolong.ye@intel.com>
    Cc: rjw@rjwysocki.net
    Cc: linux-acpi@vger.kernel.org
    Cc: guzheng1@huawei.com
    Cc: izumi.taku@jp.fujitsu.com
    Cc: lenb@kernel.org
    Link: http://lkml.kernel.org/r/1488528147-2279-4-git-send-email-douly.fnst@cn.fujitsu.com
    Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

    ---
    arch/x86/kernel/acpi/boot.c | 7 ++++++-
    arch/x86/kernel/apic/apic.c | 26 +++++++-------------------
    2 files changed, 13 insertions(+), 20 deletions(-)

    diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
    index f6b0e87..b2879cc23 100644
    --- a/arch/x86/kernel/acpi/boot.c
    +++ b/arch/x86/kernel/acpi/boot.c
    @@ -179,10 +179,15 @@ static int acpi_register_lapic(int id, u32 acpiid, u8 enabled)
    return -EINVAL;
    }

    + if (!enabled) {
    + ++disabled_cpus;
    + return -EINVAL;
    + }
    +
    if (boot_cpu_physical_apicid != -1U)
    ver = boot_cpu_apic_version;

    - cpu = __generic_processor_info(id, ver, enabled);
    + cpu = generic_processor_info(id, ver);
    if (cpu >= 0)
    early_per_cpu(x86_cpu_to_acpiid, cpu) = acpiid;

    diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
    index aee7ded..8ccb7ef 100644
    --- a/arch/x86/kernel/apic/apic.c
    +++ b/arch/x86/kernel/apic/apic.c
    @@ -2063,7 +2063,7 @@ static int allocate_logical_cpuid(int apicid)
    return nr_logical_cpuids++;
    }

    -int __generic_processor_info(int apicid, int version, bool enabled)
    +int generic_processor_info(int apicid, int version)
    {
    int cpu, max = nr_cpu_ids;
    bool boot_cpu_detected = physid_isset(boot_cpu_physical_apicid,
    @@ -2121,11 +2121,9 @@ int __generic_processor_info(int apicid, int version, bool enabled)
    if (num_processors >= nr_cpu_ids) {
    int thiscpu = max + disabled_cpus;

    - if (enabled) {
    - pr_warning("APIC: NR_CPUS/possible_cpus limit of %i "
    - "reached. Processor %d/0x%x ignored.\n",
    - max, thiscpu, apicid);
    - }
    + pr_warning("APIC: NR_CPUS/possible_cpus limit of %i "
    + "reached. Processor %d/0x%x ignored.\n",
    + max, thiscpu, apicid);

    disabled_cpus++;
    return -EINVAL;
    @@ -2177,23 +2175,13 @@ int __generic_processor_info(int apicid, int version, bool enabled)
    apic->x86_32_early_logical_apicid(cpu);
    #endif
    set_cpu_possible(cpu, true);
    -
    - if (enabled) {
    - num_processors++;
    - physid_set(apicid, phys_cpu_present_map);
    - set_cpu_present(cpu, true);
    - } else {
    - disabled_cpus++;
    - }
    + physid_set(apicid, phys_cpu_present_map);
    + set_cpu_present(cpu, true);
    + num_processors++;

    return cpu;
    }

    -int generic_processor_info(int apicid, int version)
    -{
    - return __generic_processor_info(apicid, version, true);
    -}
    -
    int hard_smp_processor_id(void)
    {
    return read_apic_id();
    \
     
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