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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id DBFC2C32771 for ; Wed, 28 Sep 2022 16:41:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:Cc:To:Subject:Message-ID:Date:From: In-Reply-To:References:MIME-Version:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=XfK6A1dDX+etanXlUGTL8zEJLWkVR8PcKcAia5tKJTg=; b=GX6GR0J1sd21XW JXoNK554IawO70AO0EHRbrbnREEChUUCaDUmC5iixeOOERemKGiWHgdA0NKRs8x5N3QNojLucfYa3 p2LHbo5XTsJv3VETYAfHCk0QcZR9REbCGRJOJ4y1Eyyt1lgK1L4tOiPzB+r1bhAPgvAvgQtQ0lDdf 5xMesLhvlSP13w2jyHEyoTLKcCgbzURgcHQDr1187Lg7zxYLrTrIM3+TASkkkMbU6HfzZsRT8ITSW TDrk+PdAsHP1dXeRt64J6gNRl0Gv0AVXtdgHMYqLT+UuFBIZwi8+fNtyjx7laxuXRo7gROr0DB8qY XTArrWzB3J+RG4yehgRA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1oda6Q-00H93i-St; Wed, 28 Sep 2022 16:40:07 +0000 Received: from mail-pf1-x434.google.com ([2607:f8b0:4864:20::434]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1oda6L-00H91z-Rd for linux-arm-kernel@lists.infradead.org; Wed, 28 Sep 2022 16:40:05 +0000 Received: by mail-pf1-x434.google.com with SMTP id l65so12989515pfl.8 for ; Wed, 28 Sep 2022 09:39:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date; bh=o0ZtcGWZNzFvp0wcIHSx/qDwHK3W4cVWO2PGHB1LS1c=; b=XZti6DE6WlXyQVPePUhXRgoWOS/rerz9MsFfOVbPOLEEBzIyws5QOPAWcdDUeGhDGE u31jUF/c5MBBrGHl4oKgKG4wvvd2rEIOiVIe1k+98ZReRU44SqZqoYlQ2Id6uB089lbj HvdnwKrn9UOt8dkrWlxYRLS+g3gwAqz7cK5GR9OtJf60AwnHBf6zTocLO19jgu3J7vo9 AXRif6rmCyWprHQo6n4mThPtrzEvHBkzEeWV7TF8ci3U2f0dFjjDryn2eHu2+ycXe5D/ ZfGrsUi9XDUx5x5Lnr02fExY0tVj2w8RJN4ML0c25k2FLxwLyEug4LsvCjLikEmSV+/8 pjmw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date; bh=o0ZtcGWZNzFvp0wcIHSx/qDwHK3W4cVWO2PGHB1LS1c=; b=WFzzdbbdGcwVBI9ishHj8ftlTozjypvQ/zJqsbfSioKiS8sL8Sv2K/n5YnbzciGNPk pUUNgVMRXrBEfhYF25PXSAAkpYpyLoIrNuuBB4t4V8oHcDjXsGGSFnAO/l/n2mal33u7 GSoKAL/9lcg9K93jCpeEIbA6VSzf4QF92H4RYBkaDL0LfjjAONMfwkae/1QCQpXSzpxL QTE9i8cCTw8tb+Um0baSZURhyueEmWQtKs0sXMbXEPDwXdxUuDsXwjsZg1rEqeBe92IO 6oDqG9GHSsc8fPHbR1x028I02Ay+J40bNn9gBiDu8EQvUTPrzzQYkA/P4yo33Hin2onL d2DA== X-Gm-Message-State: ACrzQf2BikWAdKyI21HcekZNREam1oX5dU/lyKEvVITcW2m+2isDz+2Q 0AVTOagVV0hE2od0XVwOa7sgRlKBDmcEj8SUbRdDtA== X-Google-Smtp-Source: AMsMyM6AUXk3l6t7gbTaADsa4xDkK4u+S0bN6AiVVAyB3own/m+Jg36aXqTk6IV6sma1lp9qsIaxjytl2gLCvI9BDNQ= X-Received: by 2002:a62:1ad5:0:b0:540:4830:7df6 with SMTP id a204-20020a621ad5000000b0054048307df6mr34720102pfa.37.1664383198614; Wed, 28 Sep 2022 09:39:58 -0700 (PDT) MIME-Version: 1.0 References: <20220927222851.37550-1-ndesaulniers@google.com> In-Reply-To: From: Nick Desaulniers Date: Wed, 28 Sep 2022 09:39:46 -0700 Message-ID: Subject: Re: [PATCH v2] ARM: kprobes: move __kretprobe_trampoline to out of line assembler To: "Russell King (Oracle)" , Logan Chien Cc: Masami Hiramatsu , "Naveen N . Rao" , Anil S Keshavamurthy , "David S . Miller" , Arnd Bergmann , Nathan Chancellor , Tom Rix , sparkhuang , Ard Biesheuvel , Steven Rostedt , Linus Walleij , Chen Zhongjin , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, llvm@lists.linux.dev, Naresh Kamboju , regressions@lists.linux.dev, lkft-triage@lists.linaro.org, Linux Kernel Functional Testing X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220928_094001_932266_0392C909 X-CRM114-Status: GOOD ( 15.99 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, Sep 27, 2022 at 3:35 PM Russell King (Oracle) wrote: > > On Tue, Sep 27, 2022 at 03:28:51PM -0700, Nick Desaulniers wrote: > > commit 1069c1dd20a3 ("ARM: 9231/1: Recover kretprobes return address for > > EABI stack unwinder") > > tickled a bug in clang's integrated assembler where the .save and .pad > > directives must have corresponding .fnstart directives. The integrated > > assembler is unaware that the compiler will be generating the .fnstart > > directive. > > Has it been confirmed that gcc does generate a .fnstart for naked > functions? >From what I can tell, the presence of __attribute__((naked)) makes no difference with regards to the emission of the .fnstart directive for GCC. One thing I did notice though: https://godbolt.org/z/Mv5GEobc8 GCC will emit .fnstart directives when -fasynchronous-unwind-tables is specified for C (omitting the directive otherwise), or regardless of -fasynchronous-unwind-tables/-fno-asynchronous-unwind-tables for C++. Clang will unconditionally emit .fnstart directives regardless of language mode. I don't see -fasynchronous-unwind-tables being specified under arch/arm/. But there are many instances of UNWIND(.fnstart) in various .S files under arch/arm/. https://sourceware.org/binutils/docs/as/ARM-Unwinding-Tutorial.html https://sourceware.org/binutils/docs/as/ARM-Directives.html#arm_005ffnstart > > -- > RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ > FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last! -- Thanks, ~Nick Desaulniers _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel