linux-kernel - Re: [patch] x86, apic: use 0x20 for the IRQ_MOVE_CLEANUP

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: <4B4BC572.4070002@zytor.com>
Date:	Mon, 11 Jan 2010 16:42:26 -0800
From:	"H. Peter Anvin" <hpa@...or.com>
To:	"Eric W. Biederman" <ebiederm@...ssion.com>
CC:	Suresh Siddha <suresh.b.siddha@...el.com>,
	Ingo Molnar <mingo@...e.hu>,
	Thomas Gleixner <tglx@...utronix.de>,
	Yinghai Lu <yinghai@...nel.org>,
	"Maciej W. Rozycki" <macro@...ux-mips.org>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [patch] x86, apic: use 0x20 for the IRQ_MOVE_CLEANUP_VECTOR instead
 of 0x1f

On 01/11/2010 04:28 PM, Eric W. Biederman wrote:
> 
> Without changes assign_irq_vector will reuse vectors in the range
> IRQ0_VECTOR to IRQ15_VECTOR in the code as it we currently ship it,
> when we switch irq0-15 into ioapic mode.
> 
> Switching the loop to cover IRQ0_VECTOR to IRQ15_VECTOR is not a
> problem.  I don't think it will find anything free as we assign those
> vectors on all cpus, but the data structures are fine.
> 

The question there is if we can treat the resulting ioapic IRQs as
normal movable IRQs, and just let the target-moving mechanism take care
of it.  After all, there is a discrete event at which we decide that any
particular interrupt is an IOAPIC interrupt instead of XT-PIC.
Obviously, the vectors that remain XT-PIC vectors have to remain
allocated on all vectors for all time.

Another question is why we reserve the legacy IRQ 2 vector at all --
except when ACPI is present!  I don't think it could ever be tickled,
and it sort of felt as a "just in case" thing that could be removed.

	-hpa
--
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/