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[209.132.180.67]) by mx.google.com with ESMTP id d3si5042680pfc.278.2019.04.03.03.47.30; Wed, 03 Apr 2019 03:47:45 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@nifty.com header.s=dec2015msa header.b=YLDzeOTX; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726716AbfDCKqi (ORCPT + 99 others); Wed, 3 Apr 2019 06:46:38 -0400 Received: from conssluserg-03.nifty.com ([210.131.2.82]:56431 "EHLO conssluserg-03.nifty.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725935AbfDCKqi (ORCPT ); Wed, 3 Apr 2019 06:46:38 -0400 Received: from mail-ua1-f47.google.com (mail-ua1-f47.google.com [209.85.222.47]) (authenticated) by conssluserg-03.nifty.com with ESMTP id x33AkVE4015684; Wed, 3 Apr 2019 19:46:31 +0900 DKIM-Filter: OpenDKIM Filter v2.10.3 conssluserg-03.nifty.com x33AkVE4015684 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nifty.com; s=dec2015msa; t=1554288392; bh=FY+N2gbqZqHf3UP+nQFI9TB9vzxjLOhP+YdOthD4Q+U=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=YLDzeOTX2iqpdWzuY/WCA+yzJXUBJMa3Z5vz71szmXDlPQi+A7ZBeWmlBUlsuU5CN +4fG/FPmmpxWGfnL1IcVbEOUHw/xu+uXUdml2tn0zgPi16wDO5vLNVXKGVf5atbCvm w4DETuzQsG1BictKt+4Gn/mrMAIFVAl3pt0KJSCL02qQGT9NT6rHCPB6t1t8CmNFdK MKbGRo4tFwmVuL4vjZO1sAwOMCr/6XuDZNxwFsADWRWMVSuXheDYKzVKanIxXMXabX IM4h5auwNOFozLG1Ru5bJREciqF6lionSKBWRx/fFxUCQyGdfo51swcNj7Yx0dFJ2J Xg1rvmegCjzBw== X-Nifty-SrcIP: [209.85.222.47] Received: by mail-ua1-f47.google.com with SMTP id c13so5442074uao.12; Wed, 03 Apr 2019 03:46:31 -0700 (PDT) X-Gm-Message-State: APjAAAVBJJFIyZZCt+EU178HVyIjkoZIHaFt477S90A5UKfsFAql8dG9 CSSu30o5TUmQAxP+5X4ihuve3vLANiHWoW88Vhc= X-Received: by 2002:ab0:1c1b:: with SMTP id a27mr10347563uaj.60.1554288390266; Wed, 03 Apr 2019 03:46:30 -0700 (PDT) MIME-Version: 1.0 References: <20190315101013.GN8455@Legion-PC.fortress> <20190326172411.GA15936@Legion-PC.fortress> In-Reply-To: <20190326172411.GA15936@Legion-PC.fortress> From: Masahiro Yamada Date: Wed, 3 Apr 2019 19:45:54 +0900 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [RESEND PATCH v1] moduleparam: Save information about built-in modules in separate file To: Alexey Gladkov Cc: Michal Marek , Linux Kernel Mailing List , Linux Kbuild mailing list , linux-api@vger.kernel.org, "Kirill A . Shutemov" , Gleb Fotengauer-Malinovskiy , "Dmitry V. Levin" , Dmitry Torokhov , Rusty Russell , Jessica Yu Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi. Sorry for the delay. I added some comments from the build system point of view. On Wed, Mar 27, 2019 at 2:24 AM Alexey Gladkov wrote: > > On Fri, Mar 22, 2019 at 02:34:12PM +0900, Masahiro Yamada wrote: > > Hi. > > > > (added some people to CC) > > > > > > On Fri, Mar 15, 2019 at 7:10 PM Alexey Gladkov wrote: > > > > > > Problem: > > > > > > When a kernel module is compiled as a separate module, some important > > > information about the kernel module is available via .modinfo section of > > > the module. In contrast, when the kernel module is compiled into the > > > kernel, that information is not available. > > > > > > I might be missing something, but > > vmlinux provides info of builtin modules > > in /sys/module/. > > No. There are definitely not all modules. I have a builtin sha256_generic, > but I can't find him in the /sys/module. > > > (Looks like currently only module_param and MODULE_VERSION) > > > > This patch is not exactly the same, but I see a kind of overwrap. > > I'd like to be sure if we want this new scheme. > > The /sys/module is only for running kernel. One of my use cases is > to create an initrd for a new kernel. > > > > > > Information about built-in modules is necessary in the following cases: > > > > > > 1. When it is necessary to find out what additional parameters can be > > > passed to the kernel at boot time. > > > > > > Actually, /sys/module//parameters/ > > exposes this information. > > > > Doesn't it work for your purpose? > > No, since creating an initrd needs to know all the modalias before > I get the sysfs for new kernel. Also there are no modalias at all. > > > > 2. When you need to know which module names and their aliases are in > > > the kernel. This is very useful for creating an initrd image. > > > > > > Proposal: > > > > > > The proposed patch does not remove .modinfo section with module > > > information from the vmlinux at the build time and saves it into a > > > separate file after kernel linking. So, the kernel does not increase in > > > size and no additional information remains in it. Information is stored > > > in the same format as in the separate modules (null-terminated string > > > array). Because the .modinfo section is already exported with a separate > > > modules, we are not creating a new API. > > > > > > It can be easily read in the userspace: > > > > > > $ tr '\0' '\n' < kernel.builtin.modinfo > > > ext4.softdep=pre: crc32c > > > ext4.license=GPL > > > ext4.description=Fourth Extended Filesystem > > > ext4.author=Remy Card, Stephen Tweedie, Andrew Morton, Andreas Dilger, Theodore Ts'o and others > > > ext4.alias=fs-ext4 > > > ext4.alias=ext3 > > > ext4.alias=fs-ext3 > > > ext4.alias=ext2 > > > ext4.alias=fs-ext2 > > > md_mod.alias=block-major-9-* > > > md_mod.alias=md > > > md_mod.description=MD RAID framework > > > md_mod.license=GPL > > > md_mod.parmtype=create_on_open:bool > > > md_mod.parmtype=start_dirty_degraded:int > > > ... > > > > > > Co-Developed-by: Gleb Fotengauer-Malinovskiy > > > Signed-off-by: Gleb Fotengauer-Malinovskiy > > > Signed-off-by: Alexey Gladkov > > > --- > > > Makefile | 1 + > > > include/linux/moduleparam.h | 12 +++++------- > > > scripts/link-vmlinux.sh | 8 ++++++++ > > > 3 files changed, 14 insertions(+), 7 deletions(-) > > > > > > diff --git a/Makefile b/Makefile > > > index d5713e7b1e50..971102194c92 100644 > > > --- a/Makefile > > > +++ b/Makefile > > > @@ -1288,6 +1288,7 @@ _modinst_: > > > fi > > > @cp -f $(objtree)/modules.order $(MODLIB)/ > > > @cp -f $(objtree)/modules.builtin $(MODLIB)/ > > > + @cp -f $(objtree)/kernel.builtin.modinfo $(MODLIB)/ This file should be cleaned up by 'make clean'. Please add CLEAN_FILES around line 1336. # Directories & files removed with 'make clean' CLEAN_DIRS += $(MODVERDIR) include/ksym CLEAN_FILES += ... Also, shouldn't it be added to .gitignore? > > > $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modinst > > > > > > # This depmod is only for convenience to give the initial > > > diff --git a/include/linux/moduleparam.h b/include/linux/moduleparam.h > > > index ba36506db4fb..5ba250d9172a 100644 > > > --- a/include/linux/moduleparam.h > > > +++ b/include/linux/moduleparam.h > > > @@ -10,23 +10,21 @@ > > > module name. */ > > > #ifdef MODULE > > > #define MODULE_PARAM_PREFIX /* empty */ > > > +#define __MODULE_INFO_PREFIX /* empty */ > > > #else > > > #define MODULE_PARAM_PREFIX KBUILD_MODNAME "." > > > +/* We cannot use MODULE_PARAM_PREFIX because some modules override it. */ > > > +#define __MODULE_INFO_PREFIX KBUILD_MODNAME "." > > > #endif > > > > > > /* Chosen so that structs with an unsigned long line up. */ > > > #define MAX_PARAM_PREFIX_LEN (64 - sizeof(unsigned long)) > > > > > > -#ifdef MODULE > > > #define __MODULE_INFO(tag, name, info) \ > > > static const char __UNIQUE_ID(name)[] \ > > > __used __attribute__((section(".modinfo"), unused, aligned(1))) \ > > > - = __stringify(tag) "=" info > > > -#else /* !MODULE */ > > > -/* This struct is here for syntactic coherency, it is not used */ > > > -#define __MODULE_INFO(tag, name, info) \ > > > - struct __UNIQUE_ID(name) {} > > > -#endif > > > + = __MODULE_INFO_PREFIX __stringify(tag) "=" info > > > + > > > #define __MODULE_PARM_TYPE(name, _type) \ > > > __MODULE_INFO(parmtype, name##type, #name ":" _type) > > > > > > diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh > > > index c8cf45362bd6..399d7e4d11ec 100755 > > > --- a/scripts/link-vmlinux.sh > > > +++ b/scripts/link-vmlinux.sh > > > @@ -258,10 +258,12 @@ if [ -n "${CONFIG_KALLSYMS}" ]; then > > > > > > # step 1 > > > vmlinux_link "" .tmp_vmlinux1 > > > + "${OBJCOPY}" -R .modinfo .tmp_vmlinux1 > > > kallsyms .tmp_vmlinux1 .tmp_kallsyms1.o > > > > > > # step 2 > > > vmlinux_link .tmp_kallsyms1.o .tmp_vmlinux2 > > > + "${OBJCOPY}" -R .modinfo .tmp_vmlinux2 > > > kallsyms .tmp_vmlinux2 .tmp_kallsyms2.o > > > > > > # step 3 > > > @@ -273,6 +275,7 @@ if [ -n "${CONFIG_KALLSYMS}" ]; then > > > kallsyms_vmlinux=.tmp_vmlinux3 > > > > > > vmlinux_link .tmp_kallsyms2.o .tmp_vmlinux3 > > > + "${OBJCOPY}" -R .modinfo .tmp_vmlinux3 > > > > > > kallsyms .tmp_vmlinux3 .tmp_kallsyms3.o > > > fi > > > @@ -281,6 +284,11 @@ fi > > > info LD vmlinux > > > vmlinux_link "${kallsymso}" vmlinux > > > > > > +info MODINFO kernel.builtin.modinfo > > > +"${OBJCOPY}" -j .modinfo -O binary vmlinux kernel.builtin.modinfo > > > +chmod 444 kernel.builtin.modinfo > > > +"${OBJCOPY}" -R .modinfo vmlinux > > > + > > > if [ -n "${CONFIG_BUILDTIME_EXTABLE_SORT}" ]; then > > > info SORTEX vmlinux > > > sortextable vmlinux As I pointed out before, I see lots of warnings for powerpc. How about extracting modinfo before linking vmlinux? You can extract it from vmlinux.o instead, and discard it in the linker script. diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh index dc0e8c5..994cd47 100755 --- a/scripts/link-vmlinux.sh +++ b/scripts/link-vmlinux.sh @@ -193,6 +193,9 @@ modpost_link vmlinux.o # modpost vmlinux.o to check for section mismatches ${MAKE} -f "${srctree}/scripts/Makefile.modpost" vmlinux.o +info MODINFO kernel.builtin.modinfo +"${OBJCOPY}" -j .modinfo -O binary vmlinux kernel.builtin.modinfo + kallsymso="" kallsyms_vmlinux="" diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index f8f6f04..bbb9e33 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -844,6 +844,7 @@ EXIT_CALL \ *(.discard) \ *(.discard.*) \ + *(.modinfo) \ } /** The code is simpler and I see no more warnings. I also want you to check MODULE_VERSION. If CONFIG_SYSFS is enabled, MODULE_VERSION will not be contained in the file. Thanks. > > > -- > > > 2.19.2 > > > > > > > > > -- > > Best Regards > > Masahiro Yamada > > > > -- > Rgrds, legion > -- Best Regards Masahiro Yamada