From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 200342FB086 for ; Thu, 25 Sep 2025 10:42:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.92.199 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758796979; cv=none; b=YYQ5y1TaxOINo1BXMtLMUabS28anYIel9Vh85dHFHUZ7gzTBh2j7teniJczWL/unvzCOgd+xNjFZ16+tCwAikmUGex+nazYY/GPUnx0NAGNHZdW65t8gt+VhXRGjDf4pAaduUuG7DgT/wI0x3OkDasDz/TybwOw30n3pc2Ek3XE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758796979; c=relaxed/simple; bh=UeezVNoDuhdU59b/omhxGqBB9jTFbx3XHQn1TdwEPBk=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=SeSUkaitwXCtkqIYNMztsLDGzt1LoKTPWWcPzmVrYO/UOOUhCZf2rYs/oJuYwlSkLMBDXiEgpYyTwDxrEtioJJigxilHTegNfSKPAJW7Zemct12JbyoGXEbo/W/wXAbOH2NBhYpEtJdjWo2jbspbEVo3vieJkrjLgaTloYSxM70= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=VbPz6Qqp; arc=none smtp.client-ip=90.155.92.199 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="VbPz6Qqp" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=Pcxu//loBh6joTNIURdmB6/Yb3FHDJq7TTFtNqxANwQ=; b=VbPz6QqpNCk8+BvXkXuvYlwAPy 8+YufG71f9ZCJs22wlBUcCEeW/rYGhD717Ld8rDapRPhbo2CWAh9F+NtHMHF0UzaaiRkG+i98RLBS hP9oFrmB5M0emENSM1575+rupDJ9vyTKQxGCJHP+Klg7HT7q6hbDisQ/KxMnXu9kW0fgdK3Q2xdry MtLER+vuB8Xof0RT8eXjhaTWbk9JuqZivgEOTjs15a22lT13HMTycjf+LBGcShNKyA7G6dbmPBLc+ 39h3nU4P84cdiFaN/T4dRGDmuTk7Uw//Oy3nX/Ljw8C7P7NVIL8FIiEWhCdJNW79aL5MBV8A84JBe waswnYKg==; Received: from 77-249-17-252.cable.dynamic.v4.ziggo.nl ([77.249.17.252] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.98.2 #2 (Red Hat Linux)) id 1v1jR7-0000000947G-0BY4; Thu, 25 Sep 2025 10:42:53 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id D1ACD3002BF; Thu, 25 Sep 2025 12:42:51 +0200 (CEST) Date: Thu, 25 Sep 2025 12:42:51 +0200 From: Peter Zijlstra To: Alexandre Chartre Cc: jpoimboe@kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 3/3] objtool/x86: Fix NOP decode Message-ID: <20250925104251.GZ4067720@noisy.programming.kicks-ass.net> References: <20250924134507.288529132@infradead.org> <20250924134644.154610650@infradead.org> <20250924184158.GZ3245006@noisy.programming.kicks-ass.net> <20250925100323.GY4067720@noisy.programming.kicks-ass.net> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250925100323.GY4067720@noisy.programming.kicks-ass.net> On Thu, Sep 25, 2025 at 12:03:23PM +0200, Peter Zijlstra wrote: > > > > > case 0x90: > > > > > + if (prefix != 0xf3) /* REP NOP := PAUSE */ > > > > > + insn->type = INSN_NOP; > > > > > break; > > What about 0x49 0x90, which is xchg (XCHG r8,rAX) ? 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;