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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id C190CCAC597 for ; Mon, 15 Sep 2025 08:52:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To: Content-Transfer-Encoding:Content-Type:MIME-Version:References:Message-ID: Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=DzTfZ6OkL6obc9RRZlXoM/ipHMTfVXpFSNM7FHA1pyY=; b=rKdTYIQtM5BBDHIP54mfUwXp8u uyju40bH22tv1B/Bg/pTHS1RBhzddmckPJmdmt3WPoO/7LGOpEWU8DOjsZclUkzv98uChDEJkrOA9 jQlHfuVUNWn7+nmlLuNE9XplWVBxbFKwm+uLepH39KhdgS69vjknmxWzI6drz7IWcWjxRygHvUTRK PqYBkqD/9FVkWTYeFz+PzTjn7P9AWh1x5MBVfqlzoMr269+b9omwccTm3BsZdzKYbuGGJy+P6OPCi A7pzHP0sfC1B0o1Z20gqYFALnR2HNLi9BII9SKBm9BTdZDGksrKV+fsn9xMNbgUqcBVo2lZRxt38z cS1FIrUg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uy4xA-00000003I4P-3lpG; Mon, 15 Sep 2025 08:52:52 +0000 Received: from galois.linutronix.de ([2a0a:51c0:0:12e:550::1]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1uy4x7-00000003I27-3v2r for linux-arm-kernel@lists.infradead.org; Mon, 15 Sep 2025 08:52:51 +0000 Date: Mon, 15 Sep 2025 10:52:44 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1757926366; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=DzTfZ6OkL6obc9RRZlXoM/ipHMTfVXpFSNM7FHA1pyY=; b=Mi6ywzPPfRmBkAmPmmB94PBsG5oAxNjMQaRNxHmpFFRQte/ejEj+iFvVnSU059WrUIJWPZ We53G9QOrAp0d3hHq9hkC+xDGZvWtoQmIyeRcHLWiAHtW5rwfmj8hzj0BBor/WXWLljKHr sb7mlc6wfgkb8y6RwFyC/ePJ+r7gwciLWdGro1KISwtBDOtnW5sFSBcASghzouJssqAZFl 6P72GjWYOQxrnm1zDq/kraIMBZZd+OjeyjWSpWaMoEO4TLYN1Q2++Fi76HJoLGeAx5xsai 74/lbH+OPgC4Agtx3TebC1R7gcr6b6upBqDqTUNkSLqWyJknMgoVvEGDzUMgiQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1757926366; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=DzTfZ6OkL6obc9RRZlXoM/ipHMTfVXpFSNM7FHA1pyY=; b=/8h1CSO8vFJcz/ZTIkGrrYdbGZzg3Kci40oMB631Wj5xPFCVqiizAdgJR29SEmSbNeFaaq WYGQ/mjmGmv/g1Dw== From: Sebastian Andrzej Siewior To: Ard Biesheuvel Cc: linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Ard Biesheuvel , Will Deacon , Mark Rutland , Peter Zijlstra Subject: Re: [PATCH v2 0/7] arm64: Make EFI calls preemptible Message-ID: <20250915085244.JLUfpdSP@linutronix.de> References: <20250905133035.275517-9-ardb+git@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable In-Reply-To: <20250905133035.275517-9-ardb+git@google.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250915_015250_116669_FDC4E391 X-CRM114-Status: UNSURE ( 8.16 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 2025-09-05 15:30:36 [+0200], Ard Biesheuvel wrote: > From: Ard Biesheuvel >=20 =E2=80=A6 > Note that this is only a partial solution in terms of RT guarantees, > given that the runtime services execute at the same privilege level as > the kernel, and can therefore disable interrupts (and therefore > preemption) directly. But it should prevent scheduling latency spikes > for EFI calls that simply take a long time to run to completion. That sounds nice. There is no feature flag that could tell if a specific EFI-call (or any) will disable interrupts, right? But if the source code is available, you could check. Sebastian