linux-kernel - Re: [PATCH 1/23] Make register values available to panic notifiers

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]

Date:	Wed, 14 Apr 2010 16:58:51 -0700 (PDT)
From:	David Miller <davem@...emloft.net>
To:	dhowells@...hat.com
Cc:	dvomlehn@...co.com, to@...mlehn-lnx2.corp.sa.net,
	linux-arch@...r.kernel.org, akpm@...ux-foundation.org,
	linux-kernel@...r.kernel.org, maint_arch@...mlehn-lnx2.corp.sa.net
Subject: Re: [PATCH 1/23] Make register values available to panic notifiers

From: David Howells <dhowells@...hat.com>
Date: Thu, 15 Apr 2010 00:52:14 +0100

> David VomLehn <dvomlehn@...co.com> wrote:
> 
>> > Can the use of va_start() clobber lots of registers, thereby rendering the
>> > exercise pointless on some arches?
>> >   
>>
>> The implementations I'm familiar with only need one or two registers. What
>> it *does* do is to force the contents of registers being used to pass
>> argument values onto the stack. This is roughly what gcc does for asm()
>> statements when you tell it registers are clobbered.
> 
> How about something like Sparc, where you can pass up to 8 arguments (if I
> remember correctly) in registers.  I'm not sure how Sparc handles varargs
> functions, though.

6 arguments, and all arguments get popped onto the stack into the
argument save area when doing varargs so you can access them as an
array.

Stack looks like:

	struct register_window	window;
	unsigned long args[...];
--
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/