On 10/12/2013 10:42 AM, Ingo Molnar wrote:
* H. Peter Anvin <hpa@xxxxxxxxx> 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@xxxxxxxxxxxxxx>
AuthorDate: Thu, 29 Aug 2013 18:28:04 +0900
Committer: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx>
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