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 X-Spam-Level: X-Spam-Status: No, score=-2.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F1B94C4BA0E for ; Wed, 26 Feb 2020 10:03:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B84F3206E6 for ; Wed, 26 Feb 2020 10:03:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="E83XasBZ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727709AbgBZKDL (ORCPT ); Wed, 26 Feb 2020 05:03:11 -0500 Received: from merlin.infradead.org ([205.233.59.134]:49760 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726329AbgBZKDL (ORCPT ); Wed, 26 Feb 2020 05:03:11 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; 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=U73IQx8iL6dKaqfPhIfcrYOA572OMWwK+0B2ii6t3TQ=; b=E83XasBZYeIKKAw+b8QdAE7BU4 sWEJS8SKH0nn/w6hd+5q3PRiVEWYoBVnWm421wCIEuLuUWxbw7XmfvEAXcF9pSM+SGT42fQLfOCKF yMsZ9HHqjQSfBHFpJKJXs8iDhkad8KSAAoB90ObjWr8PnZwBG9MuKqdf8i+VR0jmi4uZ+vzVCC94D uNgmA5iWiourAfGqVvU4qD/2M79rNE8rnx6M3QRWo9LY9LYZKI0vp+Y+Z960qPr3xLz8yjTL6r9bv ls6FNKhDQmMWewCEfbbkcllQb+D6UHk4ZwuFncYcsIT0/0gVogsN6+SEs/TEam+Fa/G55CFeyrpi+ fOraGaHw==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1j6tWr-00014e-W7; Wed, 26 Feb 2020 10:02:58 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id C7273300130; Wed, 26 Feb 2020 11:01:00 +0100 (CET) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 3A0C420160BF2; Wed, 26 Feb 2020 11:02:56 +0100 (CET) Date: Wed, 26 Feb 2020 11:02:56 +0100 From: Peter Zijlstra To: Thomas Gleixner Cc: LKML , x86@kernel.org, Steven Rostedt , Brian Gerst , Juergen Gross , Paolo Bonzini , Arnd Bergmann Subject: Re: [patch 00/15] x86/entry: Consolidation - Part V Message-ID: <20200226100256.GK14946@hirez.programming.kicks-ass.net> References: <20200225224719.950376311@linutronix.de> <20200226095319.GT18400@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200226095319.GT18400@hirez.programming.kicks-ass.net> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Feb 26, 2020 at 10:53:19AM +0100, Peter Zijlstra wrote: > +SYM_CODE_START_LOCAL_NOALIGN(common_idtentry) > + /* the return address is in the %gs stack slot */ > SAVE_ALL switch_stacks=1 skip_gs=1 unwind_espfix=1 > ENCODE_FRAME_POINTER > > /* fixup %gs */ > GS_TO_REG %ecx > - movl PT_GS(%esp), %edi # get the function address > - REG_TO_PTGS %ecx > + pushl PT_GS(%esp) # push return address > + REG_TO_OTGS %ecx Aside from the obvious typo, it is also completely broken because REG_TO_PGTS relies on the stack layout, which we just wrecked. movl PT_GS(%esp), %edi # get the return address REG_TO_PTGS %ecx > SET_KERNEL_GS %ecx > > /* fixup orig %eax */ > @@ -1348,9 +1348,8 @@ SYM_CODE_START_LOCAL_NOALIGN(common_exception) > movl $-1, PT_ORIG_EAX(%esp) # no syscall to restart > > movl %esp, %eax # pt_regs pointer pushl %edi > + ret > +SYM_CODE_END(common_idtentry) Should work, although that push+ret combo is a bit awkward.