Messages in this thread | | | Date | Mon, 11 Nov 2013 11:54:00 -0800 | From | "H. Peter Anvin" <> | Subject | Re: [tip:x86/bsp-hotplug] x86, apic: Disable BSP if boot cpu is AP |
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On 10/12/2013 10:42 AM, Ingo Molnar wrote: > > * H. Peter Anvin <hpa@zytor.com> wrote: > >> On 10/09/2013 04:16 PM, tip-bot for HATAYAMA Daisuke wrote: >>> Commit-ID: 1d79e607332d67d9132c176d99b5e7fabe1b6b7f >>> Gitweb: http://git.kernel.org/tip/1d79e607332d67d9132c176d99b5e7fabe1b6b7f >>> Author: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com> >>> AuthorDate: Thu, 29 Aug 2013 18:28:04 +0900 >>> Committer: H. Peter Anvin <hpa@linux.intel.com> >>> CommitDate: Wed, 9 Oct 2013 15:41:11 -0700 >>> >>> x86, apic: Disable BSP if boot cpu is AP >> >> This patch seems to trigger build failures in some configurations. >> Specifically: >> >> (.init.text+0x1307): undefined reference to `boot_cpu_is_bsp_init' >> >> Unfortunately I don't have the specific configuration which triggers the >> failure, as this was discovered by Fengguang's robot. > > I have triggered that too and have such a config, it's attached.
Okay, thinking about this again, this patchset is in fact broken on:
1. Any configuration which has CONFIG_SMP=n and CONFIG_X86_UP_APIC=n.
This is a built-time problem.
2. Any CPU which is old enough that MSR_IA32_APICBASE doesn't exist.
This is a fatal runtime bug.
3. Any clustered solution which involves a third-party cluster controller such that MSR_IA32_APICBASE may not reflect the reality of the system.
This is a less critical issue as "all" it ought to make happen is to disable some CPUs which didn't need it.
Hatayama-san, you got this build bug report almost a month ago. It looks like it is going to need a fair bit of cleanup, so I fear this is going to be dropped for v3.13.
-hpa
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