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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 33135C433F5 for ; Wed, 20 Oct 2021 14:59:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0C92160FDA for ; Wed, 20 Oct 2021 14:59:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229695AbhJTPBy (ORCPT ); Wed, 20 Oct 2021 11:01:54 -0400 Received: from mail.kernel.org ([198.145.29.99]:43700 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229570AbhJTPBy (ORCPT ); Wed, 20 Oct 2021 11:01:54 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 8646D6135F; Wed, 20 Oct 2021 14:59:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1634741980; bh=YrONzKcAhydCls+3APmmyxq1BG0aGp6PcLZnHTAcfDo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=EaG1j+7H/TUgyCZp3YkGj0cNrLC0dp5dAkO65rShX82aEdWUv2Ue/LGwv6zHvT3Kr 0CLjqEs19CQw4w6f+1pOLmRMLPnSql8KOzKBYECaNp1tHlBgAKAME1ybd/OrHb7W5m p18pBHtIgwcWLZEB1Mc22M5T6TJRGI8CKr4SiA+Jgdj95leICAe2lNwUdBNT0aBjP/ gSPWnjy5s0kf891tS1oevjuwodS0pF1FU6YsHscqDABCgmyeX9t4oxKCcVpPj9moxx PXwzJK/+x/a9KOrCnbIH/lrp89Nh6ZGSkBR/Y+0ktNbCPfKRwBy0TT51Ohbzo8R4sT amrtQaAZnH65A== Date: Wed, 20 Oct 2021 15:59:37 +0100 From: Mark Brown To: madvenka@linux.microsoft.com Cc: mark.rutland@arm.com, jpoimboe@redhat.com, ardb@kernel.org, nobuta.keiya@fujitsu.com, sjitindarsingh@gmail.com, catalin.marinas@arm.com, will@kernel.org, jmorris@namei.org, linux-arm-kernel@lists.infradead.org, live-patching@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v10 02/11] arm64: Make perf_callchain_kernel() use arch_stack_walk() Message-ID: References: <20211015025847.17694-1-madvenka@linux.microsoft.com> <20211015025847.17694-3-madvenka@linux.microsoft.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="0OjbTQTv4ED8ZjVP" Content-Disposition: inline In-Reply-To: <20211015025847.17694-3-madvenka@linux.microsoft.com> X-Cookie: I program, therefore I am. Precedence: bulk List-ID: X-Mailing-List: live-patching@vger.kernel.org --0OjbTQTv4ED8ZjVP Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Oct 14, 2021 at 09:58:38PM -0500, madvenka@linux.microsoft.com wrot= e: > From: "Madhavan T. Venkataraman" >=20 > Currently, perf_callchain_kernel() in ARM64 code walks the stack using > start_backtrace() and walk_stackframe(). Make it use arch_stack_walk() > instead. This makes maintenance easier. > static bool callchain_trace(void *data, unsigned long pc) > { > struct perf_callchain_entry_ctx *entry =3D data; > - perf_callchain_store(entry, pc); > - return true; > + return perf_callchain_store(entry, pc) =3D=3D 0; > } This changes us from unconditionally doing the whole walk to returning an error if perf_callchain_store() returns an error so it's not quite a straight transform, though since that seems like a useful improvement which most likely on't have any practical impact that's fine. Reviewed-by: Mark Brown --0OjbTQTv4ED8ZjVP Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAmFwLtgACgkQJNaLcl1U h9DGlQf9EnRXgRKnKwL2lcj9Tf5P/zGR2UVLC51sGcsAxbyAbr51NzQfPKLAEylw FI+VRW0ibqzD2wpmn9kb7boz99gz99qrlLmBzP6OTEqODAT8CVGY9YeciG9BKHtq 2Jrai3sp33jq3ox0bNtWeJ1YH1BJXlvDG+dUs7V8tytRqzOc06lVLnpmsI29g4So v5J8VVnx/UNF8jXguz16m2XPmH9C8rkgFVFAz5HxNa9gJBkCB3Gl0OeqE7cUBauz AhBkwX+T+t3IGwazfFl1LkbP1h+ikfCZ6gGLvcqsl13ZsmsfWxu3fJi6sOZobGwC VBSNqEWBYqpINLr+jp/J4mtG2929qQ== =wuCL -----END PGP SIGNATURE----- --0OjbTQTv4ED8ZjVP--