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 6DB38C25B75 for ; Wed, 29 May 2024 13:33:09 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1sCJQ3-0002CT-NJ; Wed, 29 May 2024 09:32:43 -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 1sCJQ1-0002BZ-51 for qemu-devel@nongnu.org; Wed, 29 May 2024 09:32:41 -0400 Received: from mail-ed1-x530.google.com ([2a00:1450:4864:20::530]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1sCJPy-0007be-L7 for qemu-devel@nongnu.org; Wed, 29 May 2024 09:32:40 -0400 Received: by mail-ed1-x530.google.com with SMTP id 4fb4d7f45d1cf-57883b25b50so2384698a12.2 for ; Wed, 29 May 2024 06:32:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1716989556; x=1717594356; darn=nongnu.org; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=yulUsyJIQ8oW6NmMzCSNnuTWpI0hdThdokzV/awQcLo=; b=xJVNfqCHeDGbA/bMsTWaDEht2wUHY21rXBQNkU2TCCeUPJI20s2uRUKuDb5L84Ey1W q8BZmoLMOa5dwo8wUu/PJI5OsHg4NH+tpRT8EH3g39tb5JXbQgPO3L0MRKSKq+8NfpiM UWkrBFc7Z6Rv0UT5XsuglG5uq3rk/4gwkNwedXJ7kwPx2kQ/hDgTQn/3wN4tu/ho3yxS tDeDVpAW6m3/F2di0/2jYa7hYNfbApwEkcY5qBEX1qqC48hkBGspFgyhqEb2+tzP0Ukj EyAOtPrvLQ32ttT8Keh8kmlQOYsjIUQ4BCx1d9LwjrpfWHfnl5fPlLf2x0wfQW4wbRp9 WPAg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1716989556; x=1717594356; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=yulUsyJIQ8oW6NmMzCSNnuTWpI0hdThdokzV/awQcLo=; b=aIWYBsSsRrDsH4EWCxemyLsGk7aQ5/Wxsx/HeX/TnZklanMxzOe1t/OQEFHxXts4vU eahExh7hOCVNUjkS+ce301Ods834bIBb5YLiPJG7lseqLSDWYhFFO3OyNwMR1kaB8hWj EUu7mVbafANtsC6mbVZJ0RrxUix5mU5xKPpyKeVHwB0NPwa3oyr09QqHb4hvMjsNo4bP prTmUrD0w8Z+uJSyx8EbOvvJe8ODDum2uwnDEeWzoVLesrR+jzXgSLBucL8iREvWFhBI vgNmetGfVuOXHf1ZrivA2OPfaicBVdWZEBGaInsC7BiFB6xrcELMMl3AVO9WVIrTSHgs BkpQ== X-Gm-Message-State: AOJu0YwPrdnI1bJcwewhGcHbqbLLpOVtUgvAJhPTivrNxa0y6lQ2Vug8 g6Fa6ojuI11enCsiiNOzEQINUnr/CE5+xyOQQbh6K9f4XH7vkcmgtLqO+wX07KltpbevH04bByd kDPusZAYi0cb5MsCFixJukv61nfnWS+bu8jS8WQ== X-Google-Smtp-Source: AGHT+IGI3KNfZhwy1r1YW3spaLMvSnC+J9ZmDmbxH3rcvC5OtGZWj+sNT2R+x9Q8aYrRTersCi7kwRMKgrQet50b94s= X-Received: by 2002:a50:8a9b:0:b0:578:59a8:f36c with SMTP id 4fb4d7f45d1cf-57859a8f421mr7817249a12.42.1716989556269; Wed, 29 May 2024 06:32:36 -0700 (PDT) MIME-Version: 1.0 References: <20240524232121.284515-1-richard.henderson@linaro.org> <20240524232121.284515-4-richard.henderson@linaro.org> <3f1baa61-c623-4b5b-b724-15bb68a2df3f@linaro.org> In-Reply-To: <3f1baa61-c623-4b5b-b724-15bb68a2df3f@linaro.org> From: Peter Maydell Date: Wed, 29 May 2024 14:32:22 +0100 Message-ID: Subject: Re: [PATCH v2 03/67] target/arm: Reject incorrect operands to PLD, PLDW, PLI To: Richard Henderson Cc: qemu-devel@nongnu.org, qemu-arm@nongnu.org Content-Type: text/plain; charset="UTF-8" Received-SPF: pass client-ip=2a00:1450:4864:20::530; envelope-from=peter.maydell@linaro.org; helo=mail-ed1-x530.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 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_NONE=-0.0001, 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 On Tue, 28 May 2024 at 18:36, Richard Henderson wrote: > > On 5/28/24 06:18, Peter Maydell wrote: > > On Sat, 25 May 2024 at 00:25, Richard Henderson > > wrote: > >> > >> For all, rm == 15 is invalid. > >> Prior to v8, thumb with rm == 13 is invalid. > >> For PLDW, rn == 15 is invalid. > > > >> Fixes a RISU mismatch for the HINTSPACE pattern in t32.risu > >> compared to a neoverse-n1 host. > > > > These are UNPREDICTABLE cases, not invalid. In general > > we don't try to match a specific implementation's > > UNPREDICTABLE choices. > > > > I think we're better off avoiding the mismatch by improving > > the risu patterns to avoid the UNPREDICTABLE cases. > > We do plenty of other treatments of UNPREDICTABLE as UNDEF (e.g. STREX). Why is this case > any different? It just seems like a lot of effort to go to. Sometimes we UNDEF for UNPREDICTABLEs, but quite often we say "the behaviour we get for free is fine, so no need to write extra code". In this particular case, also: * we'd need to go back and cross-check against older architecture manuals and also look at whether M-profile and A-profile are doing the same thing here * the "v8 loosens the UNPREDICTABLE case for m = 13 T1 encoding" looks suspiciously to me like a "nobody ever actually made this do anything except behave like the A1 encoding, so make T1 and A1 the same" kind of relaxation Basically, it would take me probably 15+ minutes to review the changes against the various versions of the docs and I don't think it's worth the effort :-) thanks -- PMM