From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f52.google.com (mail-wm1-f52.google.com [209.85.128.52]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6BF762F7ACE for ; Thu, 25 Sep 2025 11:29:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.52 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758799763; cv=none; b=sXFqBKiZqQLTWQMQRgR2PmGTa6aPRjj9nnCUBot09raeICDBaCWa04RMfXG9SHBb8CCwKc6Tdvh4u28ZipZ+T94lXu7mjTDbcsezHk2DM7/dBxRFmRjrwRspcCSlBTzWM2pZt/AeHAUoY2ssQoWK9Yyhl9kFS9oDJio0E0Il/VU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758799763; c=relaxed/simple; bh=N4eb4ivmGU3+zSAOaLguUis7kF3GWbFjQPyW/QLtbVE=; h=Message-ID:Date:MIME-Version:To:Cc:References:Subject:From: In-Reply-To:Content-Type; b=FMwr797xnv1pRPC4mf5Z0TWe0SmfjSxmByVcjDakcCM93RZrVZ/nwGBIX0tlvPthztXy95WRHcrAlO8SP4FlSyAOvsdlCL46EvDkCpgFqO1et+71NGstvoGuBtkxrKhTtHPeWdLqvE7to1kliFSKXylksrknYg+KoyoXEoBScA8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=citrix.com; spf=pass smtp.mailfrom=citrix.com; dkim=pass (1024-bit key) header.d=citrix.com header.i=@citrix.com header.b=BO2bFX3O; arc=none smtp.client-ip=209.85.128.52 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=citrix.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=citrix.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=citrix.com header.i=@citrix.com header.b="BO2bFX3O" Received: by mail-wm1-f52.google.com with SMTP id 5b1f17b1804b1-46e317bc647so5834175e9.2 for ; Thu, 25 Sep 2025 04:29:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=citrix.com; s=google; t=1758799760; x=1759404560; darn=vger.kernel.org; h=content-transfer-encoding:in-reply-to:autocrypt:from :content-language:subject:references:cc:to:user-agent:mime-version :date:message-id:from:to:cc:subject:date:message-id:reply-to; bh=/QqSgSXAv1zJap9Vi/qpQS5Qzz4ZHVJdj7cYYe5fWEc=; b=BO2bFX3OUmiRZEyq0Pe64ST2ZyhexGiul6e7+J4tlo6lqsFnyihEkqNyHg8KCKBvdu AF7JIEJ/1BjjaFc2gGSRdNmCY/WtnWRB6Pde/JQhOwQSWyNShmerrujR2WnCQZKd9NuD WtOVj1Dy6zd2F0IU2405o4qzaJOd6ojwnfHoU= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1758799760; x=1759404560; h=content-transfer-encoding:in-reply-to:autocrypt:from :content-language:subject:references:cc:to:user-agent:mime-version :date:message-id:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=/QqSgSXAv1zJap9Vi/qpQS5Qzz4ZHVJdj7cYYe5fWEc=; b=JzC3yW9FBdcoBwKYev1/qtoIlW4F7s9rPn5yqYlX+DTQWSM1Vthv5W1nYR0x9kbSES WjcE2WEIeI5UZ7aTvRUYwWGVP2PcfLrqb9cc3Fe9Tecd2VTjD18Vws36PpLMJwoYzHFw pfsj2v08A1q4o1xgjNChN1/s1lhE6jedCxrwRaDRyJzFtKOV3Ym88lVR9qWK4OQUEZDi 84tcUJ7UDpfHODg+GRvuASQUmm145rSmJLsoMJ0VmTEPs6uaWv6TpemXxulLe3rZxdNA SPqUMlykb5cQAfiNGSKmL9PzzG134NqMQ40ucLzsyB/TQsS+y6IypFCclYWU8rdYD/Oh 8QXw== X-Forwarded-Encrypted: i=1; AJvYcCWDrg8xigQvr7Ilt+WBe8AnH4uIBdz5u+zt36rWIExoCJ00Z+FYaukyQDI8Ty/PDNF8553duDC/tufnY8w=@vger.kernel.org X-Gm-Message-State: AOJu0Yx437IUwGK9IoiSPx3TXzKL/twNkaYjrvu0BcA5Zf2ADk/kds+l Is9GoZ1s3DNIWwSxaU1fDlx6zbWRkct0uLNUPNU0Zr9rN924OftbWZ7D+kxm3AcAhKw= X-Gm-Gg: ASbGncsRWYuoOOPmW9fe/sxpNnShCJ7CCBrx6eA3UJ5FNiVeOROaMCeq+Jdqy7nZvaF ztw/HuYxBVrM70XcnLgXkID3i/Augo1up4tYKpdT5pHBet/yOZSdW3v2Ro42cmP5Ob9T19MKYsp i7CcXUAHD/YaeZTjuHxhzeq53jFJ0AQyVGEdjEB5zmSelMUj6j+o+m52zD8eEOifwIZQ4efs5ue rAaqjFjTiZGv+C94kNg64rfledfr2sJGA46UJ9lZY0s3pdiAm6YvFBT6rN7YKVlaqsEK0nJ+6DR SlRku2KjMKxFGPNxNGCtgxmTfYudg11hR66mI4ok2bDdtRb4dyThAieOMBbmP2h6LDFg1qRM6kR RHpz4iQEe+cMRWRltrZ0GuSN2NRAaBQjuSKpzBiQDgnXOkp7EH2DHfIZAT3wSfpWEDDPR X-Google-Smtp-Source: AGHT+IHge0s3ENO9hXY4jtmVnktkVDEoCmSrCOlJG/8t/OJbeLunduZZ8YtR9kYMBs3+Gab25eMfPw== X-Received: by 2002:a05:600c:8a1b:20b0:45b:43cc:e558 with SMTP id 5b1f17b1804b1-46e32a185f0mr25214145e9.35.1758799759650; Thu, 25 Sep 2025 04:29:19 -0700 (PDT) Received: from [192.168.1.183] (host-195-149-20-212.as13285.net. [195.149.20.212]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-46e33bede2csm29692415e9.17.2025.09.25.04.29.18 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 25 Sep 2025 04:29:19 -0700 (PDT) Message-ID: Date: Thu, 25 Sep 2025 12:29:18 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird To: peterz@infradead.org Cc: alexandre.chartre@oracle.com, jpoimboe@kernel.org, linux-kernel@vger.kernel.org, x86@kernel.org References: <20250925104251.GZ4067720@noisy.programming.kicks-ass.net> Subject: Re: [PATCH 3/3] objtool/x86: Fix NOP decode Content-Language: en-GB From: Andrew Cooper Autocrypt: addr=andrew.cooper3@citrix.com; keydata= xsFNBFLhNn8BEADVhE+Hb8i0GV6mihnnr/uiQQdPF8kUoFzCOPXkf7jQ5sLYeJa0cQi6Penp VtiFYznTairnVsN5J+ujSTIb+OlMSJUWV4opS7WVNnxHbFTPYZVQ3erv7NKc2iVizCRZ2Kxn srM1oPXWRic8BIAdYOKOloF2300SL/bIpeD+x7h3w9B/qez7nOin5NzkxgFoaUeIal12pXSR Q354FKFoy6Vh96gc4VRqte3jw8mPuJQpfws+Pb+swvSf/i1q1+1I4jsRQQh2m6OTADHIqg2E ofTYAEh7R5HfPx0EXoEDMdRjOeKn8+vvkAwhviWXTHlG3R1QkbE5M/oywnZ83udJmi+lxjJ5 YhQ5IzomvJ16H0Bq+TLyVLO/VRksp1VR9HxCzItLNCS8PdpYYz5TC204ViycobYU65WMpzWe LFAGn8jSS25XIpqv0Y9k87dLbctKKA14Ifw2kq5OIVu2FuX+3i446JOa2vpCI9GcjCzi3oHV e00bzYiHMIl0FICrNJU0Kjho8pdo0m2uxkn6SYEpogAy9pnatUlO+erL4LqFUO7GXSdBRbw5 gNt25XTLdSFuZtMxkY3tq8MFss5QnjhehCVPEpE6y9ZjI4XB8ad1G4oBHVGK5LMsvg22PfMJ ISWFSHoF/B5+lHkCKWkFxZ0gZn33ju5n6/FOdEx4B8cMJt+cWwARAQABzSlBbmRyZXcgQ29v cGVyIDxhbmRyZXcuY29vcGVyM0BjaXRyaXguY29tPsLBegQTAQgAJAIbAwULCQgHAwUVCgkI CwUWAgMBAAIeAQIXgAUCWKD95wIZAQAKCRBlw/kGpdefoHbdD/9AIoR3k6fKl+RFiFpyAhvO 59ttDFI7nIAnlYngev2XUR3acFElJATHSDO0ju+hqWqAb8kVijXLops0gOfqt3VPZq9cuHlh IMDquatGLzAadfFx2eQYIYT+FYuMoPZy/aTUazmJIDVxP7L383grjIkn+7tAv+qeDfE+txL4 SAm1UHNvmdfgL2/lcmL3xRh7sub3nJilM93RWX1Pe5LBSDXO45uzCGEdst6uSlzYR/MEr+5Z JQQ32JV64zwvf/aKaagSQSQMYNX9JFgfZ3TKWC1KJQbX5ssoX/5hNLqxMcZV3TN7kU8I3kjK mPec9+1nECOjjJSO/h4P0sBZyIUGfguwzhEeGf4sMCuSEM4xjCnwiBwftR17sr0spYcOpqET ZGcAmyYcNjy6CYadNCnfR40vhhWuCfNCBzWnUW0lFoo12wb0YnzoOLjvfD6OL3JjIUJNOmJy RCsJ5IA/Iz33RhSVRmROu+TztwuThClw63g7+hoyewv7BemKyuU6FTVhjjW+XUWmS/FzknSi dAG+insr0746cTPpSkGl3KAXeWDGJzve7/SBBfyznWCMGaf8E2P1oOdIZRxHgWj0zNr1+ooF /PzgLPiCI4OMUttTlEKChgbUTQ+5o0P080JojqfXwbPAyumbaYcQNiH1/xYbJdOFSiBv9rpt TQTBLzDKXok86M7BTQRS4TZ/ARAAkgqudHsp+hd82UVkvgnlqZjzz2vyrYfz7bkPtXaGb9H4 Rfo7mQsEQavEBdWWjbga6eMnDqtu+FC+qeTGYebToxEyp2lKDSoAsvt8w82tIlP/EbmRbDVn 7bhjBlfRcFjVYw8uVDPptT0TV47vpoCVkTwcyb6OltJrvg/QzV9f07DJswuda1JH3/qvYu0p vjPnYvCq4NsqY2XSdAJ02HrdYPFtNyPEntu1n1KK+gJrstjtw7KsZ4ygXYrsm/oCBiVW/OgU g/XIlGErkrxe4vQvJyVwg6YH653YTX5hLLUEL1NS4TCo47RP+wi6y+TnuAL36UtK/uFyEuPy wwrDVcC4cIFhYSfsO0BumEI65yu7a8aHbGfq2lW251UcoU48Z27ZUUZd2Dr6O/n8poQHbaTd 6bJJSjzGGHZVbRP9UQ3lkmkmc0+XCHmj5WhwNNYjgbbmML7y0fsJT5RgvefAIFfHBg7fTY/i kBEimoUsTEQz+N4hbKwo1hULfVxDJStE4sbPhjbsPCrlXf6W9CxSyQ0qmZ2bXsLQYRj2xqd1 bpA+1o1j2N4/au1R/uSiUFjewJdT/LX1EklKDcQwpk06Af/N7VZtSfEJeRV04unbsKVXWZAk uAJyDDKN99ziC0Wz5kcPyVD1HNf8bgaqGDzrv3TfYjwqayRFcMf7xJaL9xXedMcAEQEAAcLB XwQYAQgACQUCUuE2fwIbDAAKCRBlw/kGpdefoG4XEACD1Qf/er8EA7g23HMxYWd3FXHThrVQ HgiGdk5Yh632vjOm9L4sd/GCEACVQKjsu98e8o3ysitFlznEns5EAAXEbITrgKWXDDUWGYxd pnjj2u+GkVdsOAGk0kxczX6s+VRBhpbBI2PWnOsRJgU2n10PZ3mZD4Xu9kU2IXYmuW+e5KCA vTArRUdCrAtIa1k01sPipPPw6dfxx2e5asy21YOytzxuWFfJTGnVxZZSCyLUO83sh6OZhJkk b9rxL9wPmpN/t2IPaEKoAc0FTQZS36wAMOXkBh24PQ9gaLJvfPKpNzGD8XWR5HHF0NLIJhgg 4ZlEXQ2fVp3XrtocHqhu4UZR4koCijgB8sB7Tb0GCpwK+C4UePdFLfhKyRdSXuvY3AHJd4CP 4JzW0Bzq/WXY3XMOzUTYApGQpnUpdOmuQSfpV9MQO+/jo7r6yPbxT7CwRS5dcQPzUiuHLK9i nvjREdh84qycnx0/6dDroYhp0DFv4udxuAvt1h4wGwTPRQZerSm4xaYegEFusyhbZrI0U9tJ B8WrhBLXDiYlyJT6zOV2yZFuW47VrLsjYnHwn27hmxTC/7tvG3euCklmkn9Sl9IAKFu29RSo d5bD8kMSCYsTqtTfT6W4A3qHGvIDta3ptLYpIAOD2sY3GYq2nf3Bbzx81wZK14JdDDHUX2Rs 6+ahAA== In-Reply-To: <20250925104251.GZ4067720@noisy.programming.kicks-ass.net> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit > I've made that: > > case 0x90: > if (rex_b) /* XCHG %r8, %rax */ > break; > > if (prefix == 0xf3) /* REP NOP := PAUSE */ > break; > > insn->type = INSN_NOP; > break; Legacy prefixes can come in any order.  What is F3 66 90 ? Also, VEX/EVEX/REX2 want excluding too, all of which can encode rex_b differently. Is it really only rex_b which prevents NOP becoming a pause, or is it any REX prefix?  I would have thought it was any REX prefix. ~Andrew