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 0AB44C88E4D for ; Fri, 11 Sep 2026 12:57:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To: Content-Type:MIME-Version:References:Message-ID:Subject:To:From:Date:Reply-To :Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=KvPW7wKGOhZ34dEtOElqCP0STW8GW9Yph3VIV+NYOy4=; b=WeZCEvrU1WQqlCUxZUJT3DR0aj 1/YZB242XNLCOHUMB0nc1HxD+rTQYS9aDQDi4Gwe0dna1jpOa7OlQ91gb4oy9+Gwm1y6FX9iL9ixJ By/ICNV4XJX7PVj2vvWcIHSZHUDJIPKSIm4+CeIb6KADDho0QZ4byt2/wTP6fQxAalcBYz7XIq4Ou kluTLyrrhl5vawl6uQWV16nLHCpVX6U0jsBOiP87unmSv6eErjdQnU2ojAatF109u5LVry5/Tl5Gg F4GO0/gqNCKlE+uQMpsn9oW1BpS2J7Fw3Huu+bVdvRwaBHlQ8zyLgF96zpx+eN3/N2TQ4mFsbRjP6 C+bYYW4w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1x50ov-0000000Gh5G-0243; Fri, 11 Sep 2026 12:57:33 +0000 Received: from sea.source.kernel.org ([2600:3c0a:e001:78e:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1x50ot-0000000Gh4g-3Bzp for linux-arm-kernel@lists.infradead.org; Fri, 11 Sep 2026 12:57:32 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 5EBE144801; Fri, 11 Sep 2026 12:57:31 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 55C4D1F000FF; Fri, 11 Sep 2026 12:57:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789131451; bh=KvPW7wKGOhZ34dEtOElqCP0STW8GW9Yph3VIV+NYOy4=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=ABtrpNHQBjrHI8UNkItVZR13xICohMB9qqyHFacl9IWKzwCWekVxNVh66cHEYgczo BtKsUAEFXVc9VuCD1LSZC+IyjyysF5WAvEqE4bUF7bhlQwY3PHp+KSoK9wJxZLL+XV ws0ZabKyxvxgrtobDy9Akib81YVkhPSrAimCON33XJSgbURaNvUDJ99eZPkyXLHtPJ xgP3twIB0iw11wfuZX1l83lNpTQ3baF+JMypaK70NnlX73D7cJixy9zghAaYndHYVn iozTTbGVYxe2s1/qCO23ZDZIlwV2l2OX7EIZF4PKCM/M1zDAGIpNoinKMDsea59qUY 4O5FOyfX8o6fg== Date: Fri, 11 Sep 2026 13:57:25 +0100 From: Will Deacon To: David Laight Subject: Re: [PATCH 06/21] arm64: Store 'current' in TPIDRRO_EL0 instead of SP_EL0 Message-ID: References: <20260907164247.17223-1-will@kernel.org> <20260907164247.17223-7-will@kernel.org> <20260908141950.37e9ed3d@pumpkin> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260908141950.37e9ed3d@pumpkin> 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: , Cc: Mark Rutland , Vladimir Murzin , Arnd Bergmann , Catalin Marinas , Linus Walleij , linux-kernel@vger.kernel.org, Mostafa Saleh , Marc Zyngier , David Hildenbrand , Lorenzo Stoakes , Oliver Upton , Ard Biesheuvel , linux-arm-kernel@lists.infradead.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, Sep 08, 2026 at 02:19:50PM +0100, David Laight wrote: > On Mon, 7 Sep 2026 17:42:31 +0100 > Will Deacon wrote: > > > To make SP_EL0 available to point at the per-cpu kernel overflow stack, > > we must relocate 'current' elsewhere. With TPIDRRO_EL0 now restored late > > in the return-to-user path, we can otherwise use it to hold 'current' > > and update the various accessors accordingly. > > > > Move 'current' from SP_EL0 to TPIDRRO_EL0. > > Is it worth having a #define for the name of the register that stores 'current'? > (And probably the other similar registers.) > That would avoid the bisection problems with the following two patches > and might make other code a bit more readable. We don't tend to reallocate 'current' all that often, so I don't think it's worth the indirection tbh. The following patches are to a GDB script and a bpf selftest, so I'm not going to lose sleep about bisection. Will