From patchwork Sun Jan 10 11:56:28 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexander Lobakin X-Patchwork-Id: 361132 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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS 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 EFB2CC43332 for ; Sun, 10 Jan 2021 11:57:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DB5AC2396F for ; Sun, 10 Jan 2021 11:57:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726686AbhAJL5O (ORCPT ); Sun, 10 Jan 2021 06:57:14 -0500 Received: from mail-40136.protonmail.ch ([185.70.40.136]:48240 "EHLO mail-40136.protonmail.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726685AbhAJL5O (ORCPT ); Sun, 10 Jan 2021 06:57:14 -0500 Date: Sun, 10 Jan 2021 11:56:28 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=pm.me; s=protonmail; t=1610279792; bh=NTGpJ7pXsbGsFYQgxGiOz3p29EZ/v0kLX/q+gBWkQ8E=; h=Date:To:From:Cc:Reply-To:Subject:In-Reply-To:References:From; b=EFriee+mgjrIzBkdETTflo54Fup3O5BQZmijK0J+zZwNqSgiY5ZXSo+6rYMH72p03 w+5YUXEwRODn36pdgvMgCHzqm7efrpXt+knwnJ0/AotK9IgY9q3QYdUbl0brZHUfTP RhWO9aqlZrvDHNQ6Z+jWK7AaiIdtNz/pFwGFPFJkMVQoF5yDeelqwqoRmrv9jbcYl2 SOxCxHurTbFCqkb8Kmrnvi45xBNsXDOUCVnsgr/oi1kOUWG/GsZlkEDNinbmH5O/s/ PUtwYpYw+yPXpwbyDFX/l84nVe4sZ/T49UuAFlGP/UVEh5wIt2T4fmKhtIYgkW5wsG CQjqidf5niw6Q== To: Thomas Bogendoerfer From: Alexander Lobakin Cc: Arnd Bergmann , Nathan Chancellor , Nick Desaulniers , Huacai Chen , Pei Huang , Kees Cook , Alexander Lobakin , Fangrui Song , Jiaxun Yang , Ralf Baechle , Corey Minyard , linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, stable@vger.kernel.org, clang-built-linux@googlegroups.com Reply-To: Alexander Lobakin Subject: [PATCH v5 mips-next 4/9] MIPS: properly stop .eh_frame generation Message-ID: <20210110115546.30970-4-alobakin@pm.me> In-Reply-To: <20210110115546.30970-1-alobakin@pm.me> References: <20210110115245.30762-1-alobakin@pm.me> <20210110115546.30970-1-alobakin@pm.me> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org Commit 866b6a89c6d1 ("MIPS: Add DWARF unwinding to assembly") added -fno-asynchronous-unwind-tables to KBUILD_CFLAGS to prevent compiler from emitting .eh_frame symbols. However, as MIPS heavily uses CFI, that's not enough. Use the approach taken for x86 (as it also uses CFI) and explicitly put CFI symbols into the .debug_frame section (except for VDSO). This allows us to drop .eh_frame from DISCARDS as it's no longer being generated. Fixes: 866b6a89c6d1 ("MIPS: Add DWARF unwinding to assembly") Suggested-by: Kees Cook Signed-off-by: Alexander Lobakin Reviewed-by: Kees Cook Reviewed-by: Nathan Chancellor --- arch/mips/include/asm/asm.h | 18 ++++++++++++++++++ arch/mips/kernel/vmlinux.lds.S | 1 - 2 files changed, 18 insertions(+), 1 deletion(-) diff --git a/arch/mips/include/asm/asm.h b/arch/mips/include/asm/asm.h index 3682d1a0bb80..ea4b62ece336 100644 --- a/arch/mips/include/asm/asm.h +++ b/arch/mips/include/asm/asm.h @@ -20,10 +20,27 @@ #include #include +#ifndef __VDSO__ +/* + * Emit CFI data in .debug_frame sections, not .eh_frame sections. + * We don't do DWARF unwinding at runtime, so only the offline DWARF + * information is useful to anyone. Note we should change this if we + * ever decide to enable DWARF unwinding at runtime. + */ +#define CFI_SECTIONS .cfi_sections .debug_frame +#else + /* + * For the vDSO, emit both runtime unwind information and debug + * symbols for the .dbg file. + */ +#define CFI_SECTIONS +#endif + /* * LEAF - declare leaf routine */ #define LEAF(symbol) \ + CFI_SECTIONS; \ .globl symbol; \ .align 2; \ .type symbol, @function; \ @@ -36,6 +53,7 @@ symbol: .frame sp, 0, ra; \ * NESTED - declare nested routine entry point */ #define NESTED(symbol, framesize, rpc) \ + CFI_SECTIONS; \ .globl symbol; \ .align 2; \ .type symbol, @function; \ diff --git a/arch/mips/kernel/vmlinux.lds.S b/arch/mips/kernel/vmlinux.lds.S index 09669a8fddec..10d8f0dcb76b 100644 --- a/arch/mips/kernel/vmlinux.lds.S +++ b/arch/mips/kernel/vmlinux.lds.S @@ -224,6 +224,5 @@ SECTIONS *(.options) *(.pdr) *(.reginfo) - *(.eh_frame) } }