From: peterz@infradead.org
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>,
x86@kernel.org, linux-kernel@vger.kernel.org, mbenes@suse.cz
Subject: Re: [PATCH] objtool,x86: Verify poke_int3_handler() is self contained
Date: Tue, 28 Jul 2020 10:34:29 +0200 [thread overview]
Message-ID: <20200728083429.GP119549@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <87eeowbrto.fsf@nanos.tec.linutronix.de>
On Mon, Jul 27, 2020 at 10:56:03PM +0200, Thomas Gleixner wrote:
> peterz@infradead.org writes:
> > Abuse the SMAP rules to ensure poke_int3_handler() doesn't call out to
> > anything.
>
> Yuck. Isn't that what noinstr is for or am I missing something?
Well, we don't want poke_int3_handler() to call out to noinstr either.
So noinstr only allows calling noinstr, The above hack only allows it
calling uaccess-safe functions, and the group of functions that is both
noinstr and uaccess-safe is 'small'.
But like I said yesterday, perhaps this wants it own annotation. Then we
can also verify the lack of any dynamic code.
So yes, yuck and a bad idea, ignore this ;-)
prev parent reply other threads:[~2020-07-28 8:34 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-27 10:40 [PATCH] objtool,x86: Verify poke_int3_handler() is self contained peterz
2020-07-27 11:21 ` Ingo Molnar
2020-07-27 12:50 ` peterz
2020-07-27 13:11 ` Ingo Molnar
2020-07-27 20:56 ` Thomas Gleixner
2020-07-28 8:34 ` peterz [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=20200728083429.GP119549@hirez.programming.kicks-ass.net \
--to=peterz@infradead.org \
--cc=jpoimboe@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mbenes@suse.cz \
--cc=tglx@linutronix.de \
--cc=x86@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