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=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 0FB03C47256 for ; Wed, 6 May 2020 18:10:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E927820747 for ; Wed, 6 May 2020 18:10:26 +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="UhypDkam" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730383AbgEFSKW (ORCPT ); Wed, 6 May 2020 14:10:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56684 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728892AbgEFSKW (ORCPT ); Wed, 6 May 2020 14:10:22 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 426D4C061A0F for ; Wed, 6 May 2020 11:10:22 -0700 (PDT) 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; bh=gHpMvr4vTAmGCPgtEsIXaDhEQrCbi3uAV67KLEVjxes=; b=UhypDkamACtZ+4CG4QVVyWh796 P0iO5/rVAtlEEzkWLelMKQOAEWBw6d0TJXc7XmilP9xSjHlsfsud4856OToJHY4HQUujDj7bvsocA dq7AHaDpI31TP0w6ewyFhM0MH6fYXM9iFkec4JhawvwZJhgeUpZ4z8SGEIk6A8AxfE4PlSpQqptkK JBG45/lCxDlTV9aMVwCJLR032iok3mlewjy1fd2+JbCzC/WJpA9irWjvrAddwxur/frUQnlBo+ISt IG9l1UBEZOQVpZ1PY09Icf8BaH/gGekkFzRulgXlQjrz5XKRiB/42MOi7eEf2LXu+TJZFQFi82z9m xL+D7CzQ==; 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 1jWOUi-0008OX-Gg; Wed, 06 May 2020 18:10:08 +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 D8363301EFB; Wed, 6 May 2020 20:10:05 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id BF06229DE2DD0; Wed, 6 May 2020 20:10:05 +0200 (CEST) Date: Wed, 6 May 2020 20:10:05 +0200 From: Peter Zijlstra To: x86@kernel.org Cc: linux-kernel@vger.kernel.org, rostedt@goodmis.org, mhiramat@kernel.org, bristot@redhat.com, jbaron@akamai.com, torvalds@linux-foundation.org, tglx@linutronix.de, mingo@kernel.org, namit@vmware.com, hpa@zytor.com, luto@kernel.org, ard.biesheuvel@linaro.org, jpoimboe@redhat.com, pbonzini@redhat.com, mathieu.desnoyers@efficios.com Subject: Re: [PATCH v4 15/18] static_call: Handle tail-calls Message-ID: <20200506181005.GY3762@hirez.programming.kicks-ass.net> References: <20200501202849.647891881@infradead.org> <20200501202944.650069893@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200501202944.650069893@infradead.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, May 01, 2020 at 10:29:04PM +0200, Peter Zijlstra wrote: > if (IS_ENABLED(CONFIG_HAVE_STATIC_CALL_INLINE) && site) > - __static_call_transform(site, !func, func); > + __static_call_transform(site, 2*tail + !func, func); I'm having trouble making that more readable though... that !func can be exanded like proposed in 14 without code-gen changes, but: __static_call_transform(site, tail ? (func ? JMP : RET) : (func ? CALL : NOP), func); generates a right old mess.