kexec.lists.infradead.org archive mirror
 help / color / mirror / Atom feed
From: Vivek Goyal <vgoyal@redhat.com>
To: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Cc: fengguang.wu@intel.com, kexec@lists.infradead.org,
	linux-kernel@vger.kernel.org, bp@alien8.de,
	ebiederm@xmission.com, akpm@linux-foundation.org,
	hpa@linux.intel.com, jingbai.ma@hp.com
Subject: Re: [PATCH v6 2/3] x86, apic: Add disable_cpu_apicid kernel parameter
Date: Thu, 21 Nov 2013 16:33:00 -0500	[thread overview]
Message-ID: <20131121213300.GR16208@redhat.com> (raw)
In-Reply-To: <20131121020044.2748.70221.stgit@localhost6.localdomain6>

On Thu, Nov 21, 2013 at 11:00:44AM +0900, HATAYAMA Daisuke wrote:

[..]
> @@ -2122,6 +2129,19 @@ void generic_processor_info(int apicid, int version)
>  	bool boot_cpu_detected = physid_isset(boot_cpu_physical_apicid,
>  				phys_cpu_present_map);
>  
> +	if (disabled_cpu_apicid != BAD_APICID &&
> +	    disabled_cpu_apicid != boot_cpu_physical_apicid &&

Hi Hatayama,

So we are comparing disabled_cpu_apicid with boot_cpu_physical_apicid
to make sure that one can not disable the cpu we are booting on. Can
we just read the apic id of booting cpu in local variable and compare
against that?

Something like as follows.

	if (disabled_cpu_apicid != BAD_APICID &&
	    disabled_cpu_apicid == apicid &&
	    disabled_cpu_apicid != read_apic_id()) {
		/* Disable cpu */	
	}

If above works, you will not need first patch in the series?

Thanks
Vivek

_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

  reply	other threads:[~2013-11-21 21:33 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-11-21  2:00 [PATCH v6 0/3] x86, apic, kexec: Add disable_cpu_apic kernel parameter HATAYAMA Daisuke
2013-11-21  2:00 ` [PATCH v6 1/3] x86, apic: add bios_bsp_physical_apicid HATAYAMA Daisuke
2013-11-21  2:00 ` [PATCH v6 2/3] x86, apic: Add disable_cpu_apicid kernel parameter HATAYAMA Daisuke
2013-11-21 21:33   ` Vivek Goyal [this message]
2013-11-22  0:42     ` HATAYAMA Daisuke
2013-11-22  1:59       ` Vivek Goyal
2013-11-21  2:00 ` [PATCH v6 3/3] Documentation, x86, apic, kexec: " HATAYAMA Daisuke

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20131121213300.GR16208@redhat.com \
    --to=vgoyal@redhat.com \
    --cc=akpm@linux-foundation.org \
    --cc=bp@alien8.de \
    --cc=d.hatayama@jp.fujitsu.com \
    --cc=ebiederm@xmission.com \
    --cc=fengguang.wu@intel.com \
    --cc=hpa@linux.intel.com \
    --cc=jingbai.ma@hp.com \
    --cc=kexec@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).