linux-kernel - Re: Avoiding unnecessary jump relocations in gas?

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]

Message-ID: <555A4B67.4080201@zytor.com>
Date:	Mon, 18 May 2015 13:28:23 -0700
From:	"H. Peter Anvin" <hpa@...or.com>
To:	"H.J. Lu" <hjl.tools@...il.com>
CC:	Andy Lutomirski <luto@...capital.net>,
	Borislav Petkov <bp@...en8.de>,
	Jan Beulich <JBeulich@...e.com>,
	Binutils <binutils@...rceware.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: Avoiding unnecessary jump relocations in gas?

On 05/18/2015 01:25 PM, H.J. Lu wrote:
> On Mon, May 18, 2015 at 1:06 PM, H. Peter Anvin <hpa@...or.com> wrote:
>> On 05/18/2015 01:02 PM, H.J. Lu wrote:
>>>>
>>>> I wonder if it would make sense to have explicit mnemonics for the
>>>> one-byte offset and four-byte offset jump variants.  Sometimes users
>>>> want a jump with a 32-bit offset for reasons that have nothing to do
>>>> with link-time or load-time relocations.
>>>>
>>>
>>> There is:
>>>
>>> jmp.d32 foo
>>>
>>
>> How far back does that syntax work?
>>
> 
> .d32 support was added by
> 
> commit f8a5c266971d7b5b96f973805551c6e88669cada
> Author: H.J. Lu <hjl.tools@...il.com>
> Date:   Thu Oct 14 13:31:13 2010 +0000
> 
>     Add .d32 encoding suffix.
> 
> and .d8 supported was added by
> 
> commit a501d77eeba717f6d54dce44f286f9e3aad83144
> Author: H.J. Lu <hjl.tools@...il.com>
> Date:   Fri Jan 20 20:53:50 2012 +0000
> 
>     Add .d8 suffix support to x86 assembler
> 

OK, that is probably too recent.  The simplest answer I think is just to
.balign 16 each vector.  This is init space... some extra padding really
doesn't matter.

Patch attached (still in compile test).

	-hpa


View attachment "diff" of type "text/plain" (2264 bytes)