Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752837AbbBMMdJ (ORCPT ); Fri, 13 Feb 2015 07:33:09 -0500 Received: from mail9.hitachi.co.jp ([133.145.228.44]:35240 "EHLO mail9.hitachi.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752494AbbBMMdI (ORCPT ); Fri, 13 Feb 2015 07:33:08 -0500 Message-ID: <54DDEEFB.2010107@hitachi.com> Date: Fri, 13 Feb 2015 21:32:59 +0900 From: Masami Hiramatsu Organization: Hitachi, Ltd., Japan User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:13.0) Gecko/20120614 Thunderbird/13.0.1 MIME-Version: 1.0 To: Denys Vlasenko Cc: "Frank Ch. Eigler" , Srikar Dronamraju , Ananth N Mavinakayanahalli , Jim Keniston , Oleg Nesterov , Andi Kleen , Ingo Molnar , linux-kernel@vger.kernel.org Subject: Re: [PATCH] x86: insn decoder: create artificial 3rd byte for 2-byte VEX References: <1423767879-31691-1-git-send-email-dvlasenk@redhat.com> In-Reply-To: <1423767879-31691-1-git-send-email-dvlasenk@redhat.com> Content-Type: text/plain; charset=ISO-2022-JP Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2192 Lines: 69 (2015/02/13 4:04), Denys Vlasenko wrote: > Before this patch, users need to do this to fetch vex.vvvv: > > if (insn->vex_prefix.nbytes == 2) { > vex_vvvv = ((insn->vex_prefix.bytes[1] >> 3) & 0xf) ^ 0xf; > } > if (insn->vex_prefix.nbytes == 3) { > vex_vvvv = ((insn->vex_prefix.bytes[2] >> 3) & 0xf) ^ 0xf; > } > > Make it so that insn->vex_prefix.bytes[2] always contains vex.wvvvvLpp bits. > > Signed-off-by: Denys Vlasenko Looks OK for me :) Acked-by: Masami Hiramatsu BTW, where would you use this ?? > Cc: Masami Hiramatsu > Cc: Frank Ch. Eigler > Cc: Srikar Dronamraju > Cc: Ananth N Mavinakayanahalli > Cc: Jim Keniston > Cc: Oleg Nesterov > Cc: Andi Kleen > Cc: Ingo Molnar > Cc: linux-kernel@vger.kernel.org > --- > > Masami, you were ok with this patch last time it was posted. > Can you "officially" add your Acked-By? > > arch/x86/lib/insn.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/arch/x86/lib/insn.c b/arch/x86/lib/insn.c > index 54fcffe..829ca4c 100644 > --- a/arch/x86/lib/insn.c > +++ b/arch/x86/lib/insn.c > @@ -163,6 +163,12 @@ found: > /* VEX.W overrides opnd_size */ > insn->opnd_bytes = 8; > } else { > + /* > + * For VEX2, fake VEX3-like byte#2. > + * Makes it easier to decode vex.W, vex.vvvv, > + * vex.L and vex.pp. Masking with 0x7f sets vex.W == 0. > + */ > + insn->vex_prefix.bytes[2] = b2 & 0x7f; > insn->vex_prefix.nbytes = 2; > insn->next_byte += 2; > } > -- Masami HIRAMATSU Software Platform Research Dept. Linux Technology Research Center Hitachi, Ltd., Yokohama Research Laboratory E-mail: masami.hiramatsu.pt@hitachi.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/