From patchwork Tue Dec 8 20:05:08 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: William McVicker X-Patchwork-Id: 11959561 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=-25.9 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, HK_RANDOM_FROM,INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT,USER_IN_DEF_DKIM_WL 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 5DC74C3B183 for ; Tue, 8 Dec 2020 20:22:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 41B4C2388C for ; Tue, 8 Dec 2020 20:22:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731364AbgLHUQM (ORCPT ); Tue, 8 Dec 2020 15:16:12 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36536 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731111AbgLHUN1 (ORCPT ); Tue, 8 Dec 2020 15:13:27 -0500 Received: from mail-pg1-x54a.google.com (mail-pg1-x54a.google.com [IPv6:2607:f8b0:4864:20::54a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6DCC9C061794 for ; Tue, 8 Dec 2020 12:12:47 -0800 (PST) Received: by mail-pg1-x54a.google.com with SMTP id l7so12779956pgq.16 for ; Tue, 08 Dec 2020 12:12:47 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=sender:date:in-reply-to:message-id:mime-version:references:subject :from:to:cc; bh=TNwMpONcF6c5fyj0qF7yogZGtBqg97c1j831E+RIQY0=; b=FayJQUJnMLKK6do7qAAfgkJBzPPOxnUU6bA8hMc+YFJwPEcORmbspx4Wtjz+7lFIUZ zxfWwk/OFgnIIOXmXneT1sal01uh4tp7TaMRbFY6Cf1sB7b50Xczvh0U4EArvheK2vM+ fjJ2HXA7sK9IUK3Zx1hZcdf1zO3q3kKS8/mjuH/HVZFlJcW/IET/umiN8WAqmZ3SeNtU 0WZvhfl7mFCz70Aq9B8HSMKWKNJMtjg9apgh4FuFRha+jZglg2InZQhMRAzzE+5v9K82 olR/jIlhwBwi0AsNxmpjS552jJDihQJ+Urp4FEuugCJoHxUYSTSF7vSO5wOTeELLE9dn HWaw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=TNwMpONcF6c5fyj0qF7yogZGtBqg97c1j831E+RIQY0=; b=Y49WyybOiHfq9hDtJPGxXwzUDpD27PPfoflbEXbgN53NLt9E+XmAgxoO86OSvZyTXj yG+a7ur0VmrXG46UAl+Ueq3M9dqSwTAqTANOEN+Vdc3ujJ9GRoHoOiq7+Op3VwA2aTlB fPd4lDnvZfa7ygsj1//2ykeFGnI7JflJLKJjr0eAfNChVyKm0r3WBL8oxUUL66WgLbTW wka3+yzm0ELfyNy+1+nGBYL41tl8S+lY9oTVAdyGDf5yQf0ntZ0Qo8tvYNRIvrl3dGiZ ASM3C5dLg9uenbY3IK673BpOCfUPw4TQjBXfpSZbJ8jb1OVoZoQI6DZUamUkhvkFTh9v fJyA== X-Gm-Message-State: AOAM530DPvane58l4tMO4PtbmDlvcZyllogzftn/V29stsV4GVfW2edO 0DQf2FDeEcsNOR6PuZMH4bn+v7G11njWb6mZ2DQ= X-Google-Smtp-Source: ABdhPJyYi6p1z2Y3xcfgv4GdDhh/Z9KbgqePU+uJaVTKut5mq8GVsKGl815TS5YXX3U0tm+SMmlcYQ6lBj9rlFiEaMo= Sender: "willmcvicker via sendgmr" X-Received: from willmcvicker.c.googlers.com ([fda3:e722:ac3:10:24:72f4:c0a8:2dd0]) (user=willmcvicker job=sendgmr) by 2002:a63:7510:: with SMTP id q16mr23931798pgc.382.1607457954662; Tue, 08 Dec 2020 12:05:54 -0800 (PST) Date: Tue, 8 Dec 2020 20:05:08 +0000 In-Reply-To: <20201208200508.4107399-1-willmcvicker@google.com> Message-Id: <20201208200508.4107399-3-willmcvicker@google.com> Mime-Version: 1.0 References: <20201207153116.GA15772@linux-8ccs> <20201208200508.4107399-1-willmcvicker@google.com> X-Mailer: git-send-email 2.29.2.576.ga3fc446d84-goog Subject: [PATCH v3 2/2] modules: introduce the MODULE_SCMVERSION config From: Will McVicker To: Jessica Yu , Masahiro Yamada , Michal Marek Cc: Greg Kroah-Hartman , Christoph Hellwig , Saravana Kannan , linux-kernel@vger.kernel.org, linux-kbuild@vger.kernel.org, kernel-team@android.com, Will McVicker Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org Config MODULE_SCMVERSION introduces a new module attribute -- `scmversion` -- which can be used to identify a given module's SCM version. This is very useful for developers that update their kernel independently from their kernel modules or vice-versa since the SCM version provided by UTS_RELEASE (`uname -r`) will now differ from the module's vermagic attribute. For example, we have a CI setup that tests new kernel changes on the hikey960 and db845c devices without updating their kernel modules. When these tests fail, we need to be able to identify the exact device configuration the test was using. By including MODULE_SCMVERSION, we can identify the exact kernel and modules' SCM versions for debugging the failures. Additionally, by exposing the SCM version via the sysfs node /sys/module/MODULENAME/scmversion, one can also verify the SCM versions of the modules loaded from the initramfs. Currently, modinfo can only retrieve module attributes from the module's ko on disk and not from the actual module that is loaded in RAM. You can retrieve the SCM version in two ways, 1) By using modinfo: > modinfo -F scmversion MODULENAME 2) By module sysfs node: > cat /sys/module/MODULENAME/scmversion Signed-off-by: Will McVicker --- Documentation/ABI/stable/sysfs-module | 18 ++++++++++++++++++ include/linux/module.h | 1 + init/Kconfig | 12 ++++++++++++ kernel/module.c | 2 ++ scripts/Makefile.modpost | 22 ++++++++++++++++++++++ scripts/mod/modpost.c | 24 +++++++++++++++++++++++- 6 files changed, 78 insertions(+), 1 deletion(-) diff --git a/Documentation/ABI/stable/sysfs-module b/Documentation/ABI/stable/sysfs-module index 6272ae5fb366..2ba731767737 100644 --- a/Documentation/ABI/stable/sysfs-module +++ b/Documentation/ABI/stable/sysfs-module @@ -32,3 +32,21 @@ Description: Note: If the module is built into the kernel, or if the CONFIG_MODULE_UNLOAD kernel configuration value is not enabled, this file will not be present. + +What: /sys/module/MODULENAME/scmversion +Date: November 2020 +KernelVersion: 5.11 +Contact: Will McVicker +Description: This read-only file will appear if modpost was supplied with an + SCM version for the module. It can be enabled with the config + MODULE_SCMVERSION. The SCM version is retrieved by + scripts/setlocalversion, which means that the presence of this + file depends on CONFIG_LOCALVERSION_AUTO=y or LOCALVERSION=. + When read, the SCM version that the module was compiled with is + returned. The SCM version is returned in the following format:: + + === + Git: g[a-f0-9]\+(-dirty)\? + Mercurial: hg[a-f0-9]\+(-dirty)\? + Subversion: svn[0-9]\+ + === diff --git a/include/linux/module.h b/include/linux/module.h index 6264617bab4d..63137ca5147b 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -372,6 +372,7 @@ struct module { struct module_attribute *modinfo_attrs; const char *version; const char *srcversion; + const char *scmversion; struct kobject *holders_dir; /* Exported symbols */ diff --git a/init/Kconfig b/init/Kconfig index 0872a5a2e759..7fc4be1ac62c 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -2131,6 +2131,18 @@ config MODULE_SRCVERSION_ALL the version). With this option, such a "srcversion" field will be created for all modules. If unsure, say N. +config MODULE_SCMVERSION + bool "SCM version for modules" + depends on LOCALVERSION_AUTO + help + This enables the module attribute "scmversion" which can be used + by developers to identify the SCM version of a given module, e.g. + git sha1 or hg sha1. The SCM version can be queried by modinfo or + via the sysfs node: /sys/modules/MODULENAME/scmversion. This is + useful when the kernel or kernel modules are updated separately + since that causes the vermagic of the kernel and the module to + differ. + config MODULE_SIG bool "Module signature verification" select MODULE_SIG_FORMAT diff --git a/kernel/module.c b/kernel/module.c index a4fa44a652a7..a203dab4a03b 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -807,6 +807,7 @@ static struct module_attribute modinfo_##field = { \ MODINFO_ATTR(version); MODINFO_ATTR(srcversion); +MODINFO_ATTR(scmversion); static char last_unloaded_module[MODULE_NAME_LEN+1]; @@ -1269,6 +1270,7 @@ static struct module_attribute *modinfo_attrs[] = { &module_uevent, &modinfo_version, &modinfo_srcversion, + &modinfo_scmversion, &modinfo_initstate, &modinfo_coresize, &modinfo_initsize, diff --git a/scripts/Makefile.modpost b/scripts/Makefile.modpost index f54b6ac37ac2..f1126b60adb7 100644 --- a/scripts/Makefile.modpost +++ b/scripts/Makefile.modpost @@ -66,6 +66,7 @@ ifeq ($(KBUILD_EXTMOD),) input-symdump := vmlinux.symvers output-symdump := Module.symvers +module_srcpath := $(srctree) else @@ -77,6 +78,17 @@ src := $(obj) include $(if $(wildcard $(KBUILD_EXTMOD)/Kbuild), \ $(KBUILD_EXTMOD)/Kbuild, $(KBUILD_EXTMOD)/Makefile) +# Get the external module's source path. KBUILD_EXTMOD could either be an +# absolute path or relative path from $(srctree). This makes sure that we +# aren't using a relative path from a separate working directory (O= or +# KBUILD_OUTPUT) since that may not be the actual module's SCM project path. +# So check the path relative to $(srctree) first. +ifneq ($(realpath $(srctree)/$(KBUILD_EXTMOD) 2>/dev/null),) + module_srcpath := $(srctree)/$(KBUILD_EXTMOD) +else + module_srcpath := $(KBUILD_EXTMOD) +endif + # modpost option for external modules MODPOST += -e @@ -85,6 +97,16 @@ output-symdump := $(KBUILD_EXTMOD)/Module.symvers endif +ifeq ($(CONFIG_MODULE_SCMVERSION),y) +# Get the SCM version of the module. Sed verifies setlocalversion returns +# a proper revision based on the SCM type, e.g. git, mercurial, or svn. +module_scmversion := $(shell $(srctree)/scripts/setlocalversion $(module_srcpath) | \ + sed -n 's/.*-\(\(g\|hg\)[a-fA-F0-9]\+\(-dirty\)\?\|svn[0-9]\+\).*/\1/p') +ifneq ($(module_scmversion),) +MODPOST += -v$(module_scmversion) +endif +endif + # modpost options for modules (both in-kernel and external) MODPOST += \ $(addprefix -i ,$(wildcard $(input-symdump))) \ diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index f882ce0d9327..db71e0c9ab20 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -30,6 +30,8 @@ static int have_vmlinux = 0; static int all_versions = 0; /* If we are modposting external module set to 1 */ static int external_module = 0; +#define MODULE_SCMVERSION_SIZE 64 +static char module_scmversion[MODULE_SCMVERSION_SIZE]; /* Only warn about unresolved symbols */ static int warn_unresolved = 0; /* How a symbol is exported */ @@ -2272,6 +2274,20 @@ static void add_intree_flag(struct buffer *b, int is_intree) buf_printf(b, "\nMODULE_INFO(intree, \"Y\");\n"); } +/** + * add_scmversion() - Adds the MODULE_INFO macro for the scmversion. + * @b: Buffer to append to. + * + * This function fills in the module attribute `scmversion` for the kernel + * module. This is useful for determining a given module's SCM version on + * device via /sys/modules//scmversion and/or using the modinfo tool. + */ +static void add_scmversion(struct buffer *b) +{ + if (module_scmversion[0] != '\0') + buf_printf(b, "\nMODULE_INFO(scmversion, \"%s\");\n", module_scmversion); +} + /* Cannot check for assembler */ static void add_retpoline(struct buffer *b) { @@ -2559,7 +2575,7 @@ int main(int argc, char **argv) struct dump_list *dump_read_start = NULL; struct dump_list **dump_read_iter = &dump_read_start; - while ((opt = getopt(argc, argv, "ei:mnT:o:awENd:")) != -1) { + while ((opt = getopt(argc, argv, "ei:mnT:o:awENd:v:")) != -1) { switch (opt) { case 'e': external_module = 1; @@ -2597,6 +2613,11 @@ int main(int argc, char **argv) case 'd': missing_namespace_deps = optarg; break; + case 'v': + if (!optarg) + fatal("'-v' requires an argument defining the SCM version."); + strncpy(module_scmversion, optarg, sizeof(module_scmversion) - 1); + break; default: exit(1); } @@ -2645,6 +2666,7 @@ int main(int argc, char **argv) add_depends(&buf, mod); add_moddevtable(&buf, mod); add_srcversion(&buf, mod); + add_scmversion(&buf); sprintf(fname, "%s.mod.c", mod->name); write_if_changed(&buf, fname);