linux-kernel - Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 1 Jan 2008 22:01:43 +0100
From:	Ingo Molnar <mingo@...e.hu>
To:	Christer Weinigel <christer@...nigel.se>
Cc:	Alan Cox <alan@...rguk.ukuu.org.uk>,
	"David P. Reed" <dpreed@...d.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	Rene Herman <rene.herman@...il.com>,
	Paul Rolland <rol@...917.net>, Pavel Machek <pavel@....cz>,
	Thomas Gleixner <tglx@...utronix.de>,
	linux-kernel@...r.kernel.org, Ingo Molnar <mingo@...hat.com>,
	rol@...be.net
Subject: Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.


* Christer Weinigel <christer@...nigel.se> wrote:

> On Tue, 1 Jan 2008 19:46:59 +0100
> Ingo Molnar <mingo@...e.hu> wrote:
> 
> > 
> > * Christer Weinigel <christer@...nigel.se> wrote:
> > 
> > > What I'm afraid is that udelay will be significantly slower, [...]
> > 
> > why should it be significantly slower?
> 
> out 80h, al is only two bytes.  Any alternative that has been 
> suggested in this discussion will use more space.  mov dx, alt_port; 
> out dx, al will be larger, a function call will definitely be a lot 
> larger. People have been making changes to the kernel to save a couple 
> of hundred bytes of text size.

i've done dozens of patches that saved much less of text size, so yes, i 
very much care about code size. But it has been stated in this thread 
that most of the _p() API uses in the kernel today are bogus. So 
eventually getting rid of the bogus ones will be a net code size 
_reduction_. (But even that is besides the point, we prefer clean and 
easier to maintain code.)

> I don't know if the difference in code size or the udelay will be 
> significantly slower, but I think it might be.

ok, "I dont know but it might be slower" is a perfectly fine statement 
instead of your original "it will be slower".

	Ingo
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/