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 lists.gnu.org (lists.gnu.org [209.51.188.17]) (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 AD6DBEB64D7 for ; Fri, 23 Jun 2023 13:21:11 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qCgiT-0004Vv-Qu; Fri, 23 Jun 2023 09:20:45 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qCgiP-0004Ub-GE; Fri, 23 Jun 2023 09:20:41 -0400 Received: from smtp-out2.suse.de ([2001:67c:2178:6::1d]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1qCgiN-0008JT-VL; Fri, 23 Jun 2023 09:20:41 -0400 Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id 05A0A1F74A; Fri, 23 Jun 2023 13:20:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1687526437; h=from:from:reply-to: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=j+IJ8jtLwuqSOHP4C2S0eixdjy6SYqxysCvXn2iIuPo=; b=GrZ98AWc7fxQS+KcLR6+PX/xU5dEkYuGxaS/KaDcazfLW9u/Tap/74F3sU3/AsuU2QpMV7 vP1N9KF5Xm+GQTwKAlsMAnhlYs3HdInMrlt6owzdNHGiqzXWuWcfaQBBQY8Kn/2THdMeF8 B3OJSN5veuJrNVxJiqEGMdm6M6Bhx3Y= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1687526437; h=from:from:reply-to: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=j+IJ8jtLwuqSOHP4C2S0eixdjy6SYqxysCvXn2iIuPo=; b=FG/RQqXT5+jB1jGEM8xZsXonnotRI9zWWv3kTRa9wGtLAGEJ3s5ALgPUmyGXxS/fF90JLw hyV22oHiyeSKsNCg== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 8B6CB1331F; Fri, 23 Jun 2023 13:20:36 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id iN2FFSSclWQoSgAAMHmgww (envelope-from ); Fri, 23 Jun 2023 13:20:36 +0000 From: Fabiano Rosas To: Nicholas Piggin , qemu-ppc@nongnu.org Cc: Nicholas Piggin , qemu-devel@nongnu.org, Christophe Leroy , BALATON Zoltan , Harsh Prateek Bora , Daniel Henrique Barboza , =?utf-8?Q?C=C3=A9dric?= Le Goater , David Gibson , Greg Kurz Subject: Re: [PATCH 3/4] target/ppc: Move common check in machne check handlers to a function In-Reply-To: <20230623081953.290875-4-npiggin@gmail.com> References: <20230623081953.290875-1-npiggin@gmail.com> <20230623081953.290875-4-npiggin@gmail.com> Date: Fri, 23 Jun 2023 10:20:34 -0300 Message-ID: <87edm2s4bh.fsf@suse.de> MIME-Version: 1.0 Content-Type: text/plain Received-SPF: pass client-ip=2001:67c:2178:6::1d; envelope-from=farosas@suse.de; helo=smtp-out2.suse.de X-Spam_score_int: -43 X-Spam_score: -4.4 X-Spam_bar: ---- X-Spam_report: (-4.4 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_MED=-2.3, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Nicholas Piggin writes: > From: BALATON Zoltan > > All powerpc exception handlers share some code when handling machine > check exceptions. Move this to a common function. > Maybe Machine Check is simple enough, but this kind of sharing of code has historically caused pain when people want to change something for the modern cpus and end up affecting the old cpus by mistake. There is also the inverse scenario where someone has access to the old HW and just want to make an one-off contribution, but the community gets insecure about it because it could also affect the new cpus. Then comes the obvious "solution" which is to bring in an artificial identifier (excp. model) to be able to have conditional code inside the common function. And that causes problems because no one really knows how it maps to actual hardware/ISA. No objection, just a little cautionary tale. =)