From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756683AbcBDBM3 (ORCPT ); Wed, 3 Feb 2016 20:12:29 -0500 Received: from mx1.redhat.com ([209.132.183.28]:51837 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756672AbcBDBLi (ORCPT ); Wed, 3 Feb 2016 20:11:38 -0500 From: Jessica Yu To: Rusty Russell , Josh Poimboeuf , Seth Jennings , Jiri Kosina , Vojtech Pavlik , Jonathan Corbet , Miroslav Benes Cc: linux-api@vger.kernel.org, live-patching@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, linux-doc@vger.kernel.org, Jessica Yu Subject: [RFC PATCH v4 1/6] Elf: add livepatch-specific Elf constants Date: Wed, 3 Feb 2016 20:11:06 -0500 Message-Id: <1454548271-24923-2-git-send-email-jeyu@redhat.com> In-Reply-To: <1454548271-24923-1-git-send-email-jeyu@redhat.com> References: <1454548271-24923-1-git-send-email-jeyu@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Livepatch manages its own relocation sections and symbols in order to be able to reuse module loader code to write relocations. This removes livepatch's dependence on separate "dynrela" sections to write relocations and also allows livepatch to patch modules that are not yet loaded. The livepatch Elf relocation section flag (SHF_RELA_LIVEPATCH), and symbol section index (SHN_LIVEPATCH) allow both livepatch and the module loader to identity livepatch relocation sections and livepatch symbols. Livepatch relocation sections are marked with SHF_RELA_LIVEPATCH to indicate to the module loader that it should not apply that relocation section and that livepatch will handle them. The SHN_LIVEPATCH shndx marks symbols that will be resolved by livepatch. The module loader ignores these symbols and does not attempt to resolve them. The values of these Elf constants were selected from OS-specific ranges according to the definitions from glibc. Signed-off-by: Jessica Yu --- include/uapi/linux/elf.h | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/include/uapi/linux/elf.h b/include/uapi/linux/elf.h index 71e1d0e..cb4a72f 100644 --- a/include/uapi/linux/elf.h +++ b/include/uapi/linux/elf.h @@ -282,16 +282,18 @@ typedef struct elf64_phdr { #define SHT_HIUSER 0xffffffff /* sh_flags */ -#define SHF_WRITE 0x1 -#define SHF_ALLOC 0x2 -#define SHF_EXECINSTR 0x4 -#define SHF_MASKPROC 0xf0000000 +#define SHF_WRITE 0x1 +#define SHF_ALLOC 0x2 +#define SHF_EXECINSTR 0x4 +#define SHF_RELA_LIVEPATCH 0x00100000 +#define SHF_MASKPROC 0xf0000000 /* special section indexes */ #define SHN_UNDEF 0 #define SHN_LORESERVE 0xff00 #define SHN_LOPROC 0xff00 #define SHN_HIPROC 0xff1f +#define SHN_LIVEPATCH 0xff20 #define SHN_ABS 0xfff1 #define SHN_COMMON 0xfff2 #define SHN_HIRESERVE 0xffff -- 2.4.3