From: Stafford Horne <shorne@gmail.com>
To: Richard Henderson <richard.henderson@linaro.org>
Cc: QEMU Development <qemu-devel@nongnu.org>,
"Jason A . Donenfeld" <Jason@zx2c4.com>
Subject: Re: [PATCH] target/openrisc: Do not reset delay slot flag on early tb exit
Date: Thu, 12 May 2022 07:34:51 +0900 [thread overview]
Message-ID: <Ynw6CymBBiqQgElu@antec> (raw)
In-Reply-To: <9c8c68d0-cb7c-4ec5-eac4-fd915934db5e@linaro.org>
On Wed, May 11, 2022 at 02:56:37PM -0700, Richard Henderson wrote:
> On 5/11/22 14:43, Stafford Horne wrote:
> > At this point how would tb->flags have the right value? Would it always be set
> > correctly by `cpu_get_tb_cpu_state` in the `lookup_tb_ptr`call?
>
> Well, it would be set by cpu_get_tb_cpu_state in cpu_exec, which is then
> passed to tb_gen_code. If we go around a loop and look it up a second time,
> we'll find a tb with a matching set of flags.
Right, cpu_get_tb_cpu_state called in lookup_tb_ptr will not update tb->flags.
What you mention, that is for when we have to generate a new TB, the tb->flags
get set right before tb_gen_code.
But for the case where we exit the delay-slot TB due to a pending exception I
think the flow would go.
TB chain:
-> branch-TB : set env->flag 1
-> delay-slot-TB : exit_tb due to condition
Exit:
-> return to cpu_tb_exec
-> tcg_ops->synchronize_from_tb
In this case I don't see how the tb->flag would be updated, ooh, I guess it
would have been set earlier when the TB was generated. Maybe that is what I am
missing.
-Stafford
next prev parent reply other threads:[~2022-05-11 22:36 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-11 12:05 [PATCH] target/openrisc: Do not reset delay slot flag on early tb exit Stafford Horne
2022-05-11 14:32 ` Richard Henderson
2022-05-11 21:43 ` Stafford Horne
2022-05-11 21:56 ` Richard Henderson
2022-05-11 22:34 ` Stafford Horne [this message]
2022-05-12 2:11 ` Richard Henderson
2022-05-12 12:47 ` Stafford Horne
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=Ynw6CymBBiqQgElu@antec \
--to=shorne@gmail.com \
--cc=Jason@zx2c4.com \
--cc=qemu-devel@nongnu.org \
--cc=richard.henderson@linaro.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.