From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on archive.lwn.net X-Spam-Level: X-Spam-Status: No, score=-5.7 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI,SPF_HELO_NONE,SPF_NONE autolearn=unavailable autolearn_force=no version=3.4.2 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by archive.lwn.net (Postfix) with ESMTP id B76E87DE5B for ; Tue, 13 Aug 2019 21:04:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727385AbfHMVEN (ORCPT ); Tue, 13 Aug 2019 17:04:13 -0400 Received: from mga09.intel.com ([134.134.136.24]:18661 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727253AbfHMVDo (ORCPT ); Tue, 13 Aug 2019 17:03:44 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by orsmga102.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 13 Aug 2019 14:03:42 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.64,382,1559545200"; d="scan'208";a="194276005" Received: from yyu32-desk1.sc.intel.com ([10.144.153.205]) by fmsmga001.fm.intel.com with ESMTP; 13 Aug 2019 14:03:42 -0700 From: Yu-cheng Yu To: x86@kernel.org, "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org, Arnd Bergmann , Andy Lutomirski , Balbir Singh , Borislav Petkov , Cyrill Gorcunov , Dave Hansen , Eugene Syromiatnikov , Florian Weimer , "H.J. Lu" , Jann Horn , Jonathan Corbet , Kees Cook , Mike Kravetz , Nadav Amit , Oleg Nesterov , Pavel Machek , Peter Zijlstra , Randy Dunlap , "Ravi V. Shankar" , Vedvyas Shanbhogue , Dave Martin Cc: Yu-cheng Yu Subject: [PATCH v8 13/14] x86: Discard .note.gnu.property sections Date: Tue, 13 Aug 2019 13:53:58 -0700 Message-Id: <20190813205359.12196-14-yu-cheng.yu@intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190813205359.12196-1-yu-cheng.yu@intel.com> References: <20190813205359.12196-1-yu-cheng.yu@intel.com> Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org From: "H.J. Lu" With the command-line option, -mx86-used-note=yes, the x86 assembler in binutils 2.32 and above generates a program property note in a note section, .note.gnu.property, to encode used x86 ISAs and features. To exclude .note.gnu.property sections from NOTE segment in x86 kernel linker script: PHDRS { text PT_LOAD FLAGS(5); data PT_LOAD FLAGS(6); percpu PT_LOAD FLAGS(6); init PT_LOAD FLAGS(7); note PT_NOTE FLAGS(0); } SECTIONS { ... .notes : AT(ADDR(.notes) - 0xffffffff80000000) { __start_notes = .; KEEP(*(.not e.*)) __stop_notes = .; } :text :note ... } this patch discards .note.gnu.property sections in kernel linker script by adding /DISCARD/ : { *(.note.gnu.property) } before .notes sections. Since .exit.text and .exit.data sections are discarded at runtime, it undefines EXIT_TEXT and EXIT_DATA to exclude .exit.text and .exit.data sections from default discarded sections. Signed-off-by: H.J. Lu Signed-off-by: Yu-cheng Yu --- arch/x86/kernel/vmlinux.lds.S | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S index e2feacf921a0..5ef137493a85 100644 --- a/arch/x86/kernel/vmlinux.lds.S +++ b/arch/x86/kernel/vmlinux.lds.S @@ -146,6 +146,10 @@ SECTIONS _etext = .; } :text = 0x9090 + /* .note.gnu.property sections should be discarded */ + /DISCARD/ : { + *(.note.gnu.property) + } NOTES :text :note EXCEPTION_TABLE(16) :text = 0x9090 @@ -415,6 +419,12 @@ SECTIONS STABS_DEBUG DWARF_DEBUG + /* Sections to be discarded. EXIT_TEXT and EXIT_DATA discard at + * runtime, not link time. */ +#undef EXIT_TEXT +#define EXIT_TEXT +#undef EXIT_DATA +#define EXIT_DATA DISCARDS /DISCARD/ : { *(.eh_frame) -- 2.17.1