From patchwork Fri Nov 3 16:01:01 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yuan Tan X-Patchwork-Id: 13444633 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B073AC4167D for ; Fri, 3 Nov 2023 16:01:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344868AbjKCQB2 (ORCPT ); Fri, 3 Nov 2023 12:01:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34810 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343945AbjKCQB1 (ORCPT ); Fri, 3 Nov 2023 12:01:27 -0400 Received: from bg4.exmail.qq.com (bg4.exmail.qq.com [43.154.54.12]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 41CC1D4F; Fri, 3 Nov 2023 09:01:23 -0700 (PDT) X-QQ-mid: bizesmtp78t1699027266ta08iml2 Received: from main2-ubuntu.tail147f4.ts.net ( [202.201.15.117]) by bizesmtp.qq.com (ESMTP) with id ; Sat, 04 Nov 2023 00:01:03 +0800 (CST) X-QQ-SSF: 01200000000000000000000A0000000 X-QQ-FEAT: QityeSR92A28ZPRtiE81G2IrXHWg2q27WIobMU1SAAzpzkyyfEB73YsFcjdDe bVIiFyAUAwy8zzKzjrseeMWj0rb6pexvSi+JMipbHYhQxpuclzEMg7X6cSFvfm0zUbuvUkH h53yUWwjypGaV/yCfz9llOfRSJAl345Te7BpmmwciccZriF1iTUIX3Acz0VVcqgLQLxij90 vmo9hUQ4XmPwLxfIwOPQoqiZRoQRMntdfHYmU86oxGlguDcOLX+hQcU1iiGjDNaJ56wmm5f d1CU19gnS85haVh9DhVlHm0SEjXqii66p+6zMkbYe99A6q5hm0RXrwcR0y5/I8ghUS3d/Qn 7FA36k1Kp5SCYysOg6IbHNlCGA9XQ9hupgoQtSoicunaxLd4PZDp6bU1S/y2A== X-QQ-GoodBg: 0 X-BIZMAIL-ID: 17055644200842692498 From: Yuan Tan To: falcon@tinylab.org, arnd@arndb.de, linux-kernel@vger.kernel.org, linux-mips@vger.kernel.org, linux-riscv@lists.infradead.org, luc.vanoostenryck@gmail.com, linux-sparse@vger.kernel.org Cc: linux@weissschuh.net, palmer@rivosinc.com, paul.walmsley@sifive.com, paulburton@kernel.org, paulmck@kernel.org, tim.bird@sony.com, tsbogend@alpha.franken.de, w@1wt.eu, tanyuan@tinylab.org, i@maskray.me Subject: [PATCH v1 08/14] DCE/DSE: add choice of methods to build reference for orphan sections Date: Sat, 4 Nov 2023 00:01:01 +0800 Message-Id: X-Mailer: git-send-email 2.34.1 In-Reply-To: References: MIME-Version: 1.0 X-QQ-SENDSIZE: 520 Feedback-ID: bizesmtp:tinylab.org:qybglogicsvrgz:qybglogicsvrgz5a-1 Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org Due to .pushsection producing orphan sections, the kernel currently uses `KEEP()` in the linker script to address this issue. Here we purpose two methods to build reference for pushed section, SHF_LINK_ORDER method and SECTION_SHF_GROUP method. The binary files compiled using both methods turn out to be identical, and it doesn't produce any side effects. Signed-off-by: Yuan Tan Signed-off-by: Zhangjin Wu --- init/Kconfig | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 50 insertions(+) diff --git a/init/Kconfig b/init/Kconfig index 9834dbb0ddae..9599d2de44e8 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1740,6 +1740,56 @@ config USED_SYSCALLS If unsure, please disable TRIM_UNUSED_SYSCALLS. +choice + prompt "Trim methods" if EXPERT + default RESTRICTED_TRIM_UNUSED_SYSCALLS + depends on TRIM_UNUSED_SYSCALLS + help + This option selects the method to trim unused syscall wrongly kept. + + The binary files compiled using both methods are identical. + + If the trim methods is not specified, some syscalls are kept by + linker script and can not be trimmed. + +config RESTRICTED_TRIM_UNUSED_SYSCALLS + bool "Leave some kept syscalls (EXPERIMENTAL)" if EXPERT + help + Say Y here to trim 'unused' syscalls wrongly kept by __ex_table + like sections in kernel space. + + Some syscalls are kept by linker script and can not be trimmed. + + If unsure, choose this. + +config SECTION_SHF_LINK_ORDER_SUPPORT + bool "Using SHF_LINK_ORDER attribute (EXPERIMENTAL)" if EXPERT + depends on HAVE_SECTION_SHF_LINK_ORDER_SUPPORT + help + Say Y here to trim more 'unused' syscalls wrongly kept by __ex_table + like sections in kernel space. + + This option uses the SHF_LINK_ORDER attribute to build references for + orphan sections. Therefore, these sections are no longer kept in the + linker script. + + If unsure, not choose this. + +config SECTION_SHF_GROUP_SUPPORT + bool "Using SHF_GROUP attribute (EXPERIMENTAL)" if EXPERT + depends on HAVE_SECTION_SHF_GROUP_SUPPORT + help + Say Y here to trim more 'unused' syscalls wrongly kept by __ex_table + like sections in kernel space. + + This option uses the SHF_GROUP attribute to build references for + orphan sections. Therefore, these sections are no longer kept in the + linker script. + + If unsure, not choose this. + +endchoice + config KALLSYMS bool "Load all symbols for debugging/ksymoops" if EXPERT default y