linux-kernel - Re: [PATCH] trim memory not covered by WB MTRRs

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: Windows password security audit tool. GUI, reports in PDF.

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

Message-ID: <20070607144102.GC9094@ucw.cz>
Date:	Thu, 7 Jun 2007 14:41:02 +0000
From:	Pavel Machek <pavel@....cz>
To:	Jesse Barnes <jesse.barnes@...el.com>
Cc:	Andi Kleen <andi@...stfloor.org>, linux-kernel@...r.kernel.org,
	Justin Piszcz <jpiszcz@...idpixels.com>,
	"Eric W. Biederman" <ebiederm@...ssion.com>
Subject: Re: [PATCH] trim memory not covered by WB MTRRs

Hi!

> This patch works around the problem by scanning the MTRRs at
> boot and figuring out whether the current end_pfn value (setup
> by early e820 code) goes beyond the highest WB MTRR range, and
> if so, trimming it to match.  A fairly obnoxious KERN_WARNING
> is printed too, letting the user know that not all of their
> memory is available due to a likely BIOS bug.

Way too obnoxious warning, I'd say. Just drop the *s.

> +	if ((highest_addr >> PAGE_SHIFT) != end_pfn) {
> +		printk(KERN_WARNING "***************\n");
> +		printk(KERN_WARNING "**** WARNING: likely BIOS bug\n");
> +		printk(KERN_WARNING "**** MTRRs don't cover all of "
> +		       "memory, trimmed %ld pages\n", end_pfn -
> +		       (highest_addr >> PAGE_SHIFT));
> +		printk(KERN_WARNING "***************\n");
> +		end_pfn = highest_addr >> PAGE_SHIFT;

...and I'd print lost memory in kilobytes, to be more luser-friendly.

							Pavel

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
-
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/