From: Keir Fraser <keir@xen.org>
To: maheen butt <maheen_butt26@yahoo.com>,
"xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>
Subject: Re: set_current in Xen booting sequence
Date: Mon, 03 Dec 2012 17:54:39 +0000 [thread overview]
Message-ID: <CCE297DF.54A0A%keir@xen.org> (raw)
In-Reply-To: <1354520163.12932.YahooMailNeo@web120002.mail.ne1.yahoo.com>
[-- Attachment #1.1: Type: text/plain, Size: 947 bytes --]
It¹s a dummy or poison value to catch invalid use of current before it is
properly set up.
-- Keir
On 03/12/2012 07:36, "maheen butt" <maheen_butt26@yahoo.com> wrote:
> Hi all,
>
> I'm investigating Xen bootup sequence and I'm stuck with the function
> set_current((struct vcpu *)0xfffff000);
> the high level idea is that it is assigning VCPU to physical CPU but I can't
> understand the following
>
> 1) what is the need of this hard coded address? it is seemed that vcpu exist
> on this address (but no idea who put vcpu on that particular address)?
> (the same address is passed both in case of ARM and X86)
> 2) no idea about what exactly get_cpu_info() (called by set_current) is
> doing.. (logically doing & and or with sp register)?
>
> Thanks
>
>
>
>
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xen.org
> http://lists.xen.org/xen-devel
[-- Attachment #1.2: Type: text/html, Size: 1719 bytes --]
[-- Attachment #2: Type: text/plain, Size: 126 bytes --]
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
prev parent reply other threads:[~2012-12-03 17:54 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-03 7:36 set_current in Xen booting sequence maheen butt
2012-12-03 8:50 ` Jan Beulich
2012-12-03 17:54 ` Keir Fraser [this message]
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=CCE297DF.54A0A%keir@xen.org \
--to=keir@xen.org \
--cc=maheen_butt26@yahoo.com \
--cc=xen-devel@lists.xensource.com \
/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).