From: Peng Fan <van.freenix@gmail.com>
To: Wei Chen <wei.chen@linaro.org>
Cc: julien.grall@arm.com, sstabellini@kernel.org,
steve.capper@arm.com, xen-devel@lists.xen.org
Subject: Re: [PATCH 4/4] xen/arm: arm64: Remove MPIDR multiprocessing extensions check
Date: Wed, 25 May 2016 20:37:37 +0800 [thread overview]
Message-ID: <20160525123727.GA18234@linux-7smt.suse> (raw)
In-Reply-To: <1464142211-343-1-git-send-email-Wei.Chen@linaro.org>
Hi Wei,
On Wed, May 25, 2016 at 10:10:11AM +0800, Wei Chen wrote:
>In ARM64, the MPIDR multiprocessing extensions bit is reserved to 1.
>So, the value check for this bit is no longer necessary on ARM64.
From ARM DDI0487A.G, I found the U bit for MPIDR_EL1:
"
Indicates a Uniprocessor system, as distinct from PE 0 in a multiprocessor system. The possible
values of this bit are:
0 Processor is part of a multiprocessor system.
1 Processor is part of a uniprocessor system.
"
It's not reserved to 1. Which doc are you refering to?
Regards,
Peng.
>
>Signed-off-by: Wei Chen <Wei.Chen@linaro.org>
>---
> xen/arch/arm/arm64/head.S | 1 -
> 1 file changed, 1 deletion(-)
>
>diff --git a/xen/arch/arm/arm64/head.S b/xen/arch/arm/arm64/head.S
>index 3090beb..91e2817 100644
>--- a/xen/arch/arm/arm64/head.S
>+++ b/xen/arch/arm/arm64/head.S
>@@ -267,7 +267,6 @@ common_start:
> * find that multiprocessor extensions are
> * present and the system is SMP */
> mrs x0, mpidr_el1
>- tbz x0, _MPIDR_SMP, 1f /* Multiprocessor extension not supported? */
> tbnz x0, _MPIDR_UP, 1f /* Uniprocessor system? */
>
> ldr x13, =(~MPIDR_HWID_MASK)
>--
>2.7.4
>
>
>_______________________________________________
>Xen-devel mailing list
>Xen-devel@lists.xen.org
>http://lists.xen.org/xen-devel
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
next prev parent reply other threads:[~2016-05-25 12:37 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-25 2:10 [PATCH 4/4] xen/arm: arm64: Remove MPIDR multiprocessing extensions check Wei Chen
2016-05-25 12:37 ` Peng Fan [this message]
2016-05-25 13:31 ` Julien Grall
2016-05-25 14:11 ` Julien Grall
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=20160525123727.GA18234@linux-7smt.suse \
--to=van.freenix@gmail.com \
--cc=julien.grall@arm.com \
--cc=sstabellini@kernel.org \
--cc=steve.capper@arm.com \
--cc=wei.chen@linaro.org \
--cc=xen-devel@lists.xen.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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.