linux-kernel - Re: [PATCH 01/14] Introduce cpu_enabled

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: <20080715102130.GA22866@flint.arm.linux.org.uk>
Date:	Tue, 15 Jul 2008 11:21:30 +0100
From:	Russell King <rmk+lkml@....linux.org.uk>
To:	Andi Kleen <andi@...stfloor.org>
Cc:	Matthew Wilcox <matthew@....cx>, Alex Chiang <achiang@...com>,
	linux-kernel@...r.kernel.org, linux-arch@...r.kernel.org,
	linux-acpi@...r.kernel.org
Subject: Re: [PATCH 01/14] Introduce cpu_enabled_map and friends

On Tue, Jul 15, 2008 at 12:03:27PM +0200, Andi Kleen wrote:
> Matthew Wilcox <matthew@....cx> writes:
> >
> > I don't understand why we want to know about these CPUs.  Surely they
> > should be 'possible', but not 'present'?  What useful thing can Linux do
> > with them?
> 
> He explained it in the intro, near the end (I nearly complained about
> this too when I hadn't finished reading it completely :):
> 
> |The big picture implication is that we can allow userspace
> |to interact with disabled CPUs. In this particular example,
> |we provide a knob that lets a sysadmin schedule any present
> |CPU for firmware deconfiguration or enablement.
> 
> The reason sounds pretty exotic, but ok.

I don't see why this needs to be cross architecture then - shouldn't
the generic kernel only be concerning itself with things that are
possible, present and/or online?

If you have an interface which allows you to change the machines
configuration in a machine specific way, shouldn't that be something
for that machine to support and forced upon the entire kernel?

-- 
Russell King
 Linux kernel    2.6 ARM Linux   - http://www.arm.linux.org.uk/
 maintainer of:
--
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/