Messages in this thread | | | Date | Tue, 20 Mar 2018 19:26:12 +0100 (CET) | From | Thomas Gleixner <> | Subject | Re: [PATCH v6 1/2] of: Documentation: Specify local APIC ID in "reg" |
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On Tue, 20 Mar 2018, Ivan Gorinov wrote:
> On Mon, Mar 19, 2018 at 07:39:52PM -0500, Rob Herring wrote: > > On Tue, Mar 13, 2018 at 5:05 PM, Ivan Gorinov <ivan.gorinov@intel.com> wrote: > > > Use the "reg" property to specify the processor's local APIC ID. > > > Local APIC ID is assigned by hardware and may differ from CPU number. > > > > Is "CPU number" a s/w visible h/w number or has it just been an index > > for DT? In the latter case, I'm okay with this change. In the former > > case, you should stick to the existing numbering. For example on ARM, > > the number here corresponds to a core ID number in a register called > > MPIDR. > > The latter case. Apparently, "CPU number" was just an index in the list. > Local APIC ID is the s/w visible h/w assigned number. > Some processor models allow local APIC ID to be changed by software, but > CPUID instruction executed with %eax = 0x0b always returns the initial ID > assigned by hardware in %edx. > > APIC ID does not match index in the list in many systems.
Please document that in the changelog.
Thanks,
tglx
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