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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4304CC433FE for ; Tue, 18 Oct 2022 20:17:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230073AbiJRURh (ORCPT ); Tue, 18 Oct 2022 16:17:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46512 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229543AbiJRURe (ORCPT ); Tue, 18 Oct 2022 16:17:34 -0400 Received: from relay3-d.mail.gandi.net (relay3-d.mail.gandi.net [217.70.183.195]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 028FD6687B for ; Tue, 18 Oct 2022 13:17:32 -0700 (PDT) Received: (Authenticated sender: joao@overdrivepizza.com) by mail.gandi.net (Postfix) with ESMTPA id 78B4060007; Tue, 18 Oct 2022 20:17:28 +0000 (UTC) MIME-Version: 1.0 Date: Tue, 18 Oct 2022 13:17:28 -0700 From: Joao Moreira To: Peter Zijlstra Cc: Kees Cook , x86@kernel.org, Sami Tolvanen , linux-kernel@vger.kernel.org, Mark Rutland , Josh Poimboeuf Subject: Re: [PATCH] x86/ibt: Implement FineIBT In-Reply-To: References: <202210181020.79AF7F7@keescook> Message-ID: X-Sender: joao@overdrivepizza.com Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > >> Tangent: why are these nop instead of 0xcc? These bytes aren't >> executed >> ever are they? > > Because that's what the compiler gets us through > -fpatchable-function-entry. Is it useful to get the compiler to emit 0xcc with -fpatchable-function-entry under any circumstance? I can probably change that quickly if needed/useful.