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=-2.2 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 58B8BC04AB1 for ; Thu, 9 May 2019 09:27:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2933A21479 for ; Thu, 9 May 2019 09:27:56 +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="WcNQDklE" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726589AbfEIJ1z (ORCPT ); Thu, 9 May 2019 05:27:55 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:53116 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725826AbfEIJ1y (ORCPT ); Thu, 9 May 2019 05:27:54 -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=mh9wv/1YPcHFRafECtG9vJbg2xftnq1zTlCLnERm8MU=; b=WcNQDklEwzguV0Z8pENKDWZGy q0ZhOFX23ffs/Z0ITznG7dFVyKrFXBU1mzR0rEH9ph2nFYgCZgEoCJ8NYQ8PiM/HXqGsgzPAN/t2N hOf8xuAdOAgu3dZ/mA1bKacT3QmaI64yJcgDYx5eKV17UA8zIVQ2/DraLKQGFyAC2SYX3GzBp5L5P B/25wkTsE2uUU6lYGClvMLTLCup3Jp7aN28XJ1dnTFAC+LMBIe6SRJ78XHXCppfLNkn32F2FEJbh1 72aI8gkU0C2UZxwH7dZ9qVXTFo6XheLrzDxnH03Wv3NafxemGD8/KGKZ2+JNxgaFYSZ9/2w15WaPk /8Im51tRw==; 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 1hOfL2-0004y6-SB; Thu, 09 May 2019 09:27:41 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id C2EF029CD4D51; Thu, 9 May 2019 11:27:38 +0200 (CEST) Date: Thu, 9 May 2019 11:27:38 +0200 From: Peter Zijlstra To: Masami Hiramatsu Cc: Josh Poimboeuf , linux-kernel@vger.kernel.org, Linus Torvalds , Ingo Molnar , Andrew Morton , Andy Lutomirski , Nicolai Stange , Thomas Gleixner , Borislav Petkov , "H. Peter Anvin" , x86@kernel.org, Jiri Kosina , Miroslav Benes , Petr Mladek , Joe Lawrence , Shuah Khan , Konrad Rzeszutek Wilk , Tim Chen , Sebastian Andrzej Siewior , Mimi Zohar , Juergen Gross , Nick Desaulniers , Nayna Jain , Masahiro Yamada , Joerg Roedel , linux-kselftest@vger.kernel.org Subject: Re: [PATCH 2/4] x86/kprobes: Fix frame pointer annotations Message-ID: <20190509092738.GK2650@hirez.programming.kicks-ass.net> References: <20190508074901.982470324@infradead.org> <20190508080612.721269814@infradead.org> <20190508115416.nblx7c2kocidpytm@treble> <20190508120416.GL2589@hirez.programming.kicks-ass.net> <20190508124248.u5ukpbhnh4wpiccq@treble> <20190508153907.GM2589@hirez.programming.kicks-ass.net> <20190508184848.qerg3flv3ej3xsev@treble> <20190509102030.dfa62e058f09d0d8cbdd6053@kernel.org> <20190509081431.GO2589@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190509081431.GO2589@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 Thu, May 09, 2019 at 10:14:31AM +0200, Peter Zijlstra wrote: > struct ftrace_regs_stack { > ftrace_func_t func; > unsigned long parent_ip; > }; > > void ftrace_regs_handler(struct pr_regs *regs) > { > struct ftrace_regs_stack *st = (void *)regs->sp; > ftrace_func_t func = st->func; > > regs->sp += sizeof(long); /* pop func */ > > func(regs->ip, st->parent_ip, function_trace_op, regs); > } Alternatively we can add things like: static inline unsigned long int3_emulate_pop(struct pt_regs *regs) { unsigned long val = *(unsigned long *)regs->sp; regs->sp += sizeof(unsigned long); return val; } And do: ftrace_func_t func = (void *)int3_emulate_pop(regs);