From: Richard Henderson <rth@twiddle.net>
To: Paolo Bonzini <pbonzini@redhat.com>,
Laurent Vivier <laurent@vivier.eu>,
Aurelien Jarno <aurelien@aurel32.net>,
John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH v2] target-sh4: add atomic tas
Date: Thu, 3 Nov 2016 13:15:03 -0600 [thread overview]
Message-ID: <31e426f8-56a3-e4ea-ac55-36848cffeea9@twiddle.net> (raw)
In-Reply-To: <3d88d6c0-6730-0db4-c109-a33b9165fb00@redhat.com>
On 11/03/2016 11:52 AM, Paolo Bonzini wrote:
> UP kernel = no sane way to implement this in user-mode qemu?
Probably no straight-forward way, no.
> Another possibility is to treat the load as a LL and the store as a SC
> (implemented in turn with cmpxchg+branch if it fails). cmpxchg spans
> two basic blocks, so maybe one also needs to look at r0 and sp in
> cpu_get_tb_cpu_state...
Yeah, that's a possibility. With the store-conditional failure auto-branching
back to the start of the sequence (r0+sp).
> Anyhow this patch seems like a bugfix.
Absolutely.
r~
next prev parent reply other threads:[~2016-11-03 19:15 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-03 14:07 [Qemu-devel] [PATCH v2] target-sh4: add atomic tas Laurent Vivier
2016-11-03 14:53 ` Richard Henderson
2016-11-03 15:32 ` Paolo Bonzini
2016-11-03 15:35 ` Laurent Vivier
2016-11-03 16:18 ` Paolo Bonzini
2016-11-03 16:21 ` Laurent Vivier
2016-11-03 16:51 ` Laurent Vivier
2016-11-03 16:51 ` Richard Henderson
2016-11-03 17:52 ` Paolo Bonzini
2016-11-03 19:15 ` Richard Henderson [this message]
2016-11-04 9:23 ` John Paul Adrian Glaubitz
2016-11-04 9:43 ` John Paul Adrian Glaubitz
2016-11-04 9:53 ` Laurent Vivier
2016-11-04 10:00 ` John Paul Adrian Glaubitz
2016-11-04 10:13 ` Paolo Bonzini
2016-11-04 10:16 ` John Paul Adrian Glaubitz
2016-11-04 10:52 ` Paolo Bonzini
2016-11-04 0:02 ` Aurelien Jarno
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=31e426f8-56a3-e4ea-ac55-36848cffeea9@twiddle.net \
--to=rth@twiddle.net \
--cc=aurelien@aurel32.net \
--cc=glaubitz@physik.fu-berlin.de \
--cc=laurent@vivier.eu \
--cc=pbonzini@redhat.com \
--cc=qemu-devel@nongnu.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).