From: Paulo Marques <pmarques@grupopie.com>
To: Al Boldi <a1426z@gawab.com>
Cc: Arjan van de Ven <arjan@infradead.org>,
Frank van Maarseveen <frankvm@frankvm.com>,
linux-kernel@vger.kernel.org, Andi Kleen <ak@suse.de>
Subject: Re: [PATCH] x86: Don't randomize stack unless current->personality permits it
Date: Mon, 17 Jul 2006 16:50:02 +0100 [thread overview]
Message-ID: <44BBB1AA.3050703@grupopie.com> (raw)
In-Reply-To: <200607151709.45870.a1426z@gawab.com>
Al Boldi wrote:
>[...] > void fn() {
>
> long i = 9999999;
> double x,y;
>
> elapsed(1);
> while (i--) fn2(&x,&y);
> printf("%4lu ",elapsed(0));
> }
You are not initializing x and y and with -Os at least my gcc really
uses floating point load/store operations to handle that code.
Maybe the coprocessor has a hard time normalizing certain garbage on the
stack, but without/with randomization the data comes from other
addresses and you're just lucky with the contents.
Does this also happens if you add a "x=0, y=0;" line to that function?
--
Paulo Marques - www.grupopie.com
Pointy-Haired Boss: I don't see anything that could stand in our way.
Dilbert: Sanity? Reality? The laws of physics?
next prev parent reply other threads:[~2006-07-17 15:50 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-07-11 19:57 [PATCH] x86: Don't randomize stack unless current->personality permits it Al Boldi
2006-07-12 16:03 ` Andi Kleen
2006-07-12 20:12 ` Al Boldi
2006-07-12 20:27 ` Arjan van de Ven
2006-07-12 21:13 ` Al Boldi
2006-07-13 9:44 ` Frank van Maarseveen
2006-07-13 20:51 ` Al Boldi
2006-07-13 20:54 ` Arjan van de Ven
2006-07-15 11:29 ` Al Boldi
2006-07-15 12:22 ` Arjan van de Ven
2006-07-15 14:09 ` Al Boldi
2006-07-15 16:15 ` Arjan van de Ven
2006-07-15 17:39 ` Al Boldi
2006-07-17 15:50 ` Paulo Marques [this message]
2006-07-18 5:21 ` Al Boldi
-- strict thread matches above, loose matches on Subject: below --
2006-07-25 0:21 Chuck Ebbert
2006-07-25 4:57 ` Al Boldi
2006-07-19 17:02 Chuck Ebbert
2006-07-20 17:23 ` Al Boldi
2006-07-24 15:57 ` Al Boldi
2006-07-16 3:58 Chuck Ebbert
2006-07-16 19:49 ` Al Boldi
2006-07-11 15:22 Frank van Maarseveen
2006-07-11 20:11 ` Arjan van de Ven
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=44BBB1AA.3050703@grupopie.com \
--to=pmarques@grupopie.com \
--cc=a1426z@gawab.com \
--cc=ak@suse.de \
--cc=arjan@infradead.org \
--cc=frankvm@frankvm.com \
--cc=linux-kernel@vger.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