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=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,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 8833ACA9EBB for ; Thu, 24 Oct 2019 17:40:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5CF73205ED for ; Thu, 24 Oct 2019 17:40:55 +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="PJZB6Tpz" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2503925AbfJXRkv (ORCPT ); Thu, 24 Oct 2019 13:40:51 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:38946 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729458AbfJXRku (ORCPT ); Thu, 24 Oct 2019 13:40:50 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.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:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=sTRjbq+OPzLWUvcUX+QGFONGylrzn8uKiZz+7VSqigI=; b=PJZB6Tpzh5Aa/T8Oj7iXr+SiH KSLUJzsBbcu4Wt4VQZOV0+q7a0ezabFIdj/GsokzzbOMRdXkAt6K64HUq8HjMEU1wzyLmJYtQGw/A MTR1caxgCqtx4M2Kyu2JFRZfyrBYKseRn9ZWlgsbj6uOp90nQsuQTAEVQfjQhAdwH5RYJdgwzBbFH mZvimTAcQ08s6HinxaD/LnZ1R6Ko/ig1ePM2YFjXRXyWgynIuuHGqrxWKjRcEvpSL0FujLqfbS6W5 lmSrLuaG+XME4tOyCKf6znNZ8DHEkwM7z39DBmkRxWrz4foFJiK5BoqbdgRTxDvO7R1zuzwjhkr8q jM8puMTDQ==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1iNh6M-0003eN-T2; Thu, 24 Oct 2019 17:40:47 +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 C5F5C306CF9; Thu, 24 Oct 2019 19:39:45 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 6109A2B1D8927; Thu, 24 Oct 2019 19:40:44 +0200 (CEST) Date: Thu, 24 Oct 2019 19:40:44 +0200 From: Peter Zijlstra To: Andy Lutomirski Cc: Thomas Gleixner , LKML , X86 ML , Will Deacon , Paolo Bonzini , kvm list , linux-arch , Mike Rapoport , Josh Poimboeuf , Miroslav Benes Subject: Re: [patch V2 08/17] x86/entry: Move syscall irq tracing to C code Message-ID: <20191024174044.GJ4114@hirez.programming.kicks-ass.net> References: <20191023122705.198339581@linutronix.de> <20191023123118.386844979@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Thu, Oct 24, 2019 at 09:24:13AM -0700, Andy Lutomirski wrote: > On Wed, Oct 23, 2019 at 2:30 PM Andy Lutomirski wrote: > > > > On Wed, Oct 23, 2019 at 5:31 AM Thomas Gleixner wrote: > > > > > > Interrupt state tracing can be safely done in C code. The few stack > > > operations in assembly do not need to be covered. > > > > > > Remove the now pointless indirection via .Lsyscall_32_done and jump to > > > swapgs_restore_regs_and_return_to_usermode directly. > > > > This doesn't look right. > > Well, I feel a bit silly. I read this: > > > > > > #define SYSCALL_EXIT_WORK_FLAGS \ > > > @@ -279,6 +282,9 @@ static void syscall_slow_exit_work(struc > > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > > and I applied the diff in my head to the wrong function, and I didn't > notice that it didn't really apply there. Oddly, gitweb gets this I had the same when reviewing these patches; I was almost going to ask tglx about it on IRC when the penny dropped.