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H A D | trace-events | diff e6d0c3ce689585ad8f38c826e69ee04fb2c2257c Mon Dec 09 07:09:00 CST 2019 Igor Mammedov <imammedo@redhat.com> acpi: cpuhp: introduce 'Command data 2' field
No functional change in practice, patch only aims to properly document (in spec and code) intended usage of the reserved space.
The new field is to be used for 2 purposes: - detection of modern CPU hotplug interface using CPHP_GET_NEXT_CPU_WITH_EVENT_CMD command. procedure will be described in follow up patch: "acpi: cpuhp: spec: add typical usecases" - for returning upper 32 bits of architecture specific CPU ID, for new CPHP_GET_CPU_ID_CMD command added by follow up patch: "acpi: cpuhp: add CPHP_GET_CPU_ID_CMD command"
Change is backward compatible with 4.2 and older machines, as field was unconditionally reserved and always returned 0x0 if modern CPU hotplug interface was enabled.
Signed-off-by: Igor Mammedov <imammedo@redhat.com> Message-Id: <1575896942-331151-8-git-send-email-imammedo@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Laszlo Ersek <lersek@redhat.com>
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H A D | cpu.c | diff e6d0c3ce689585ad8f38c826e69ee04fb2c2257c Mon Dec 09 07:09:00 CST 2019 Igor Mammedov <imammedo@redhat.com> acpi: cpuhp: introduce 'Command data 2' field
No functional change in practice, patch only aims to properly document (in spec and code) intended usage of the reserved space.
The new field is to be used for 2 purposes: - detection of modern CPU hotplug interface using CPHP_GET_NEXT_CPU_WITH_EVENT_CMD command. procedure will be described in follow up patch: "acpi: cpuhp: spec: add typical usecases" - for returning upper 32 bits of architecture specific CPU ID, for new CPHP_GET_CPU_ID_CMD command added by follow up patch: "acpi: cpuhp: add CPHP_GET_CPU_ID_CMD command"
Change is backward compatible with 4.2 and older machines, as field was unconditionally reserved and always returned 0x0 if modern CPU hotplug interface was enabled.
Signed-off-by: Igor Mammedov <imammedo@redhat.com> Message-Id: <1575896942-331151-8-git-send-email-imammedo@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Laszlo Ersek <lersek@redhat.com>
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