From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5F5FFC4338F for ; Wed, 11 Aug 2021 12:31:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3CF1660C41 for ; Wed, 11 Aug 2021 12:31:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229917AbhHKMcD (ORCPT ); Wed, 11 Aug 2021 08:32:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56188 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229776AbhHKMb6 (ORCPT ); Wed, 11 Aug 2021 08:31:58 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2303FC029836; Wed, 11 Aug 2021 05:28:23 -0700 (PDT) From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1628684901; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=b3CyKvJaEwwphnaIVpCFl46BS2WMQuydG6Z8cqn8/sI=; b=Mk2d2aB9aImBYcA7SGIdR5B8V+7ToAlmLvva2lilX9fJ15PIGwsH/DLzqlnV4UQXoPynFX Cx89eyTyx9YI2H3S/Xfu+pal8SPg1YqSchb2ycdhLt6Vmc3AjiF6MeqE99nPYqPW4BIGOg BgGeWH+mvdf63Y8NG/IOASWAPzhBMlXFo/O8pxwjKcsng7W2MKhEyc0sys9on3bEWYcHSE WOe34U+S0ZEy7Wx9rgbMzewFNOZEn0xb+qJHYBD7sXVInmTTUJGxyt5BiNkhmUJkWBFgYz eXN2yqUd6g1GMpNNG662I5P9OIzrDgk4y6y/U3cuoDiNJYqX6WmqD5KfGRYn0w== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1628684901; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=b3CyKvJaEwwphnaIVpCFl46BS2WMQuydG6Z8cqn8/sI=; b=BSsIIwvRVuLmwPE6k7Z6GJb6pkJ7BpmY7Pcu7PKjdASNEOJUJQAoxA6q7STVlkNzYavErX zGQZmCIPdaNWZUCQ== To: Marc Zyngier , Valentin Schneider Cc: linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org, Will Deacon , Mark Rutland , Sebastian Andrzej Siewior , Mel Gorman , Ard Biesheuvel Subject: Re: [SPLAT 2/3] irqchip/gic-v3-its: Sleeping spinlocks down gic_reserve_range() In-Reply-To: <87y2989xhh.wl-maz@kernel.org> References: <20210810134127.1394269-1-valentin.schneider@arm.com> <20210810134127.1394269-3-valentin.schneider@arm.com> <87y2989xhh.wl-maz@kernel.org> Date: Wed, 11 Aug 2021 14:28:21 +0200 Message-ID: <87a6lop3mi.ffs@tglx> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Aug 11 2021 at 09:50, Marc Zyngier wrote: > On Tue, 10 Aug 2021 14:41:26 +0100, > Valentin Schneider wrote: > The issue is that although the redistributor tables have been > allocated ahead of time (outside of any cpuhp callback), they cannot > be programmed into the RDs until the corresponding CPUs have been > brought up (the registers may not be accessible). > > For the same reason, we don't know whether we can free them (because > there is already a table programmed there) or have to reserve them > with an efi_mem_reserve_persistent() call. efi_mem_reserve_iomem() > uses GFP_ATOMIC for its allocation, but this is not sufficient for RT > anymore. > > We could postpone the reservation of the memory to a later point (it > is only useful for kexec), but it isn't clear where that point is. The > CPU is not quite up yet, and we can't easily IPI the boot CPU to do > the reserve call. Right, but don't you know about the need for reservation _before_ bringing the CPU up? Thanks, tglx