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_PASS,USER_AGENT_MUTT autolearn=ham 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 784B6C65C31 for ; Sat, 6 Oct 2018 12:12:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1B9542147D for ; Sat, 6 Oct 2018 12:12:46 +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="lmGquFOr" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1B9542147D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727866AbeJFTPp (ORCPT ); Sat, 6 Oct 2018 15:15:45 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:41366 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727658AbeJFTPp (ORCPT ); Sat, 6 Oct 2018 15:15:45 -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=aG1FcGFSDYIVigsvtdAWrXnZDykDmhyslHi2bgdrC88=; b=lmGquFOrlfRhXDZ36VVpnS6fy CbrYFdRKe45XL2b6DMWvhvLkDBDPzLo1IZAY4njt5r9kAJUnzTdUIgMj0MTVreVN/F15WOPx8Kaq4 A5SZVvUBFe9exl2c0e5FJGBGuNxx/xe8SZhDYdRg9YzN5p9TMKZBp8j5p9a/RDx7AYCIf9ph/X2Qv uTOn8sWO2OhzAifxo5mUoTLmItFiyPRG/ZbigBiGFOkLfFqRjyoqC6EnWNmRnVEC+yC/Vbam7/BMG qL7JyzxlOlBJA8nmFDRMHxthWBTCHNdqVZ6GDwi+1sKq9poIaAdScB2mh+9+WfMBEOZ+Ft6EExJIz VEqyFGqFg==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1g8lRU-0006jv-2T; Sat, 06 Oct 2018 12:12:20 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 917DC201EF080; Sat, 6 Oct 2018 14:12:11 +0200 (CEST) Date: Sat, 6 Oct 2018 14:12:11 +0200 From: Peter Zijlstra To: Steven Rostedt Cc: linux-kernel@vger.kernel.org, Linus Torvalds , Ingo Molnar , Andrew Morton , Thomas Gleixner , Masami Hiramatsu , Mathieu Desnoyers , Matthew Helsley , "Rafael J . Wysocki" , David Woodhouse , Paolo Bonzini , Josh Poimboeuf , Jason Baron , Jiri Kosina , ard.biesheuvel@linaro.org, Andy Lutomirski Subject: Re: [POC][RFC][PATCH 1/2] jump_function: Addition of new feature "jump_function" Message-ID: <20181006121211.GA5663@hirez.programming.kicks-ass.net> References: <20181006015110.653946300@goodmis.org> <20181006015720.634688468@goodmis.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181006015720.634688468@goodmis.org> 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 Fri, Oct 05, 2018 at 09:51:11PM -0400, Steven Rostedt wrote: > +#define arch_dynfunc_trampoline(name, def) \ > + asm volatile ( \ > + ".globl dynfunc_" #name "; \n\t" \ > + "dynfunc_" #name ": \n\t" \ > + "jmp " #def " \n\t" \ > + ".balign 8 \n \t" \ > + : : : "memory" ) Bah, what is it with you people and trampolines. Why can't we, just like jump_label, patch the call directly? The whole call+jmp thing is silly, don't do that. It just wrecks I$ and is slower for no real reason afaict. Steve, also see: https://lkml.kernel.org/r/20181005081333.15018-1-ard.biesheuvel@linaro.org