linux-kernel - Re: [PATCH 08/12] irqdomain: Replace LEGACY mapping with LINEAR

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: <CACxGe6v_nz5pw8xjcy2-ewcZehY_KO0tgRO7=DtWOJS-e5uXMg@mail.gmail.com>
Date:	Sat, 16 Jun 2012 00:16:32 -0600
From:	Grant Likely <grant.likely@...retlab.ca>
To:	Benjamin Herrenschmidt <benh@...nel.crashing.org>
Cc:	linux-kernel@...r.kernel.org, Milton Miller <miltonm@....com>,
	Paul Mundt <lethal@...ux-sh.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Rob Herring <rob.herring@...xeda.com>
Subject: Re: [PATCH 08/12] irqdomain: Replace LEGACY mapping with LINEAR

On Sat, Jun 16, 2012 at 12:01 AM, Benjamin Herrenschmidt
<benh@...nel.crashing.org> wrote:
> On Fri, 2012-06-15 at 23:01 -0600, Grant Likely wrote:
>> The LEGACY mapping unnecessarily complicates the irqdomain code and
>> can easily be implemented with a linear mapping.  By ripping it out
>> and replacing it with the LINEAR mapping the object size of
>> irqdomain.c shrinks by about 330 bytes (ARMv7) which offsets the
>> additional allocation required by the linear map.  It also makes it
>> possible for current LEGACY map users to pre-allocate irq_descs for a
>> subset of the hwirqs and dynamically allocate the rest as needed.
>
> The point of legacy was to reserve 0...15, they could only be handed out
> to that controller, that guarantees that ancient crap x86 drivers with
> hard coded irq numbers would fail ... unless you have an x86-style
> chipset (PReP, some CHRP, ...).
>
> I'd like to keep that functionality a way or another.

The functionality is still entirely there; it's just implemented with
a linear map that gets populated with mappings to reserved irqs.
Everything *should* keep working correctly.

g.
--
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/