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2021-06-17kbuild: mkcompile_h: consider timestamp if KBUILD_BUILD_TIMESTAMP is setMatthias Maennich
To avoid unnecessary recompilations, mkcompile_h does not regenerate compile.h if just the timestamp changed. Though, if KBUILD_BUILD_TIMESTAMP is set, an explicit timestamp for the build was requested, in which case we should not ignore it. If a user follows the documentation for reproducible builds [1] and defines KBUILD_BUILD_TIMESTAMP as the git commit timestamp, a clean build will have the correct timestamp. A subsequent cherry-pick (or amend) changes the commit timestamp and if an incremental build is done with a different KBUILD_BUILD_TIMESTAMP now, that new value is not taken into consideration. But it should for reproducibility. Hence, whenever KBUILD_BUILD_TIMESTAMP is explicitly set, do not ignore UTS_VERSION when making a decision about whether the regenerated version of compile.h should be moved into place. [1] https://www.kernel.org/doc/html/latest/kbuild/reproducible-builds.html Signed-off-by: Matthias Maennich <maennich@google.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-05-27kbuild: clean up ${quiet} checks in shell scriptsMasahiro Yamada
There were efforts to make 'make -s' really silent when it is a warning-free build. The conventional way was to let a shell script check ${quiet}, and if it is 'silent_', suppress the stdout by itself. With the previous commit, the 'cmd' takes care of it now. The 'cmd' is also invoked from if_changed, if_changed_dep, and if_changed_rule. You can omit ${quiet} checks in shell scripts when they are invoked from the 'cmd' macro. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-10-21kbuild: Use uname for LINUX_COMPILE_HOST detectionChris Down
`hostname` may not be present on some systems as it's not mandated by POSIX/SUSv4. This isn't just a theoretical problem: on Arch Linux, `hostname` is provided by `inetutils`, which isn't part of the base distribution. ./scripts/mkcompile_h: line 38: hostname: command not found Use `uname -n` instead, which is more likely to be available (and mandated by standards). Signed-off-by: Chris Down <chris@chrisdown.name> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-05-12kbuild: use CONFIG_CC_VERSION_TEXT to construct LINUX_COMPILER macroMasahiro Yamada
scripts/mkcompile_h runs $(CC) just for getting the version string. Reuse CONFIG_CC_VERSION_TEXT for optimization. For GCC, this slightly changes the version string. I do not think it is a big deal as we do not have the defined format for LINUX_COMPILER. In fact, the recent commit 4dcc9a88448a ("kbuild: mkcompile_h: Include $LD version in /proc/version") added the linker version. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-04-09kbuild: mkcompile_h: Include $LD version in /proc/versionKees Cook
When doing Clang builds of the kernel, it is possible to link with either ld.bfd (binutils) or ld.lld (LLVM), but it is not possible to discover this from a running kernel. Add the "$LD -v" output to /proc/version. Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Tested-by: Nathan Chancellor <natechancellor@gmail.com> Reviewed-by: Fangrui Song <maskray@google.com> Reviewed-by: Sedat Dilek <sedat.dilek@gmail.com> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-03-02kbuild: remove the owner check in mkcompile_hMasahiro Yamada
This reverts a very old commit, which dates back to the pre-git era: |commit 5d1cfb5b12f72145d30ba0f53c9f238144b122b8 |Author: Kai Germaschewski <kai@tp1.ruhr-uni-bochum.de> |Date: Sat Jul 27 02:53:19 2002 -0500 | | kbuild: Fix compiling/installing as different users | | "make bzImage && sudo make install" had the problem that during | the "sudo make install" the build system would notice that the information | in include/linux/compile.h is not accurate (it says "compiled by <user>", | but we are root), thus causing compile.h to be updated and leading to | some recompiles. | | We now only update "compile.h" if the current user is the owner of | include/linux/autoconf.h, i.e. the user who did the "make *config". So the | above sequence will correctly state "compiled by <user>". | |diff --git a/scripts/mkcompile_h b/scripts/mkcompile_h |index 6313db96172..cd956380978 100755 |--- a/scripts/mkcompile_h |+++ b/scripts/mkcompile_h |@@ -3,6 +3,17 @@ ARCH=$2 | SMP=$3 | CC=$4 | |+# If compile.h exists already and we don't own autoconf.h |+# (i.e. we're not the same user who did make *config), don't |+# modify compile.h |+# So "sudo make install" won't change the "compiled by <user>" |+# do "compiled by root" |+ |+if [ -r $TARGET -a ! -O ../include/linux/autoconf.h ]; then |+ echo ' (not modified)' |+ exit 0 |+fi |+ | if [ -r ../.version ]; then | VERSION=`cat ../.version` | else The 'make bzImage && sudo make install' problem no longer happens because commit 1648e4f80506 ("x86, kbuild: make "make install" not depend on vmlinux") fixed the root cause. Commit 19514fc665ff ("arm, kbuild: make "make install" not depend on vmlinux") fixed the similar issue on ARM, with detailed explanation. So, the rule is that the installation targets should never trigger the builds of any build artifact. By following it, this check is unneeded. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2019-12-14mkcompile_h: use printf for LINUX_COMPILE_BYMasahiro Yamada
Commit 858805b336be ("kbuild: add $(BASH) to run scripts with bash-extension") shed light on portability issues. Here is another one. Since commit f07726048d59 ("Fix handling of backlash character in LINUX_COMPILE_BY name"), we must escape a backslash contained in LINUX_COMPILE_BY. This is not working on such distros as Ubuntu. As the POSIX spec [1] says, if any of the operands contain a backslash ( '\' ) character, the results are implementation-defined. The actual shell of /bin/sh could be bash, dash, etc. depending on distros, and the behavior of builtin echo command is different among them. The bash builtin echo, unless -e is given, copies the arguments to stdout without expanding escape sequences (BSD-like behavior). The dash builtin echo, in contrast, adopts System V behavior, which does expand escape sequences without any option given. Even non-builtin /bin/echo behaves differently depending on the system. Due to these variations, echo is considered as a non-portable command. Using printf is the common solution to avoid the portability issue. [1] https://pubs.opengroup.org/onlinepubs/009695399/utilities/echo.html Fixes: 858805b336be ("kbuild: add $(BASH) to run scripts with bash-extension") Reported-by: XXing Wei <xxing.wei@unisoc.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2019-12-14mkcompile_h: git rid of UTS_TRUNCATE from LINUX_COMPILE_{BY,HOST}Masahiro Yamada
UTS_VERSION is set to struct uts_namespace, hence a too long string should be truncated so it fits in 64 characters. On the other hand, LINUX_COMPILE_BY/HOST are not set to uts_namespace. They are just used in the banners, which do not have specific length limitation. I dug into the git history, but I could not find the reason why these two strings must fit in 64 characters. Remove them. Now that UTS_VERSION is the only user of UTS_TRUNCATE, I squashed it. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2019-08-14Kbuild: Handle PREEMPT_RT for version string and magicThomas Gleixner
Update the build scripts and the version magic to reflect when CONFIG_PREEMPT_RT is enabled in the same way as CONFIG_PREEMPT is treated. The resulting version strings: Linux m 5.3.0-rc1+ #100 SMP Fri Jul 26 ... Linux m 5.3.0-rc1+ #101 SMP PREEMPT Fri Jul 26 ... Linux m 5.3.0-rc1+ #102 SMP PREEMPT_RT Fri Jul 26 ... The module vermagic: 5.3.0-rc1+ SMP mod_unload modversions 5.3.0-rc1+ SMP preempt mod_unload modversions 5.3.0-rc1+ SMP preempt_rt mod_unload modversions Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-01-28kbuild: remove unnecessary in-subshell executionMasahiro Yamada
The commands surrounded by ( ) are executed in a subshell, but in most cases, we do not need to spawn an extra subshell. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2017-11-17Merge tag 'kbuild-v4.15' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild updates from Masahiro Yamada: "One of the most remarkable improvements in this cycle is, Kbuild is now able to cache the result of shell commands. Some variables are expensive to compute, for example, $(call cc-option,...) invokes the compiler. It is not efficient to redo this computation every time, even when we are not actually building anything. Kbuild creates a hidden file ".cache.mk" that contains invoked shell commands and their results. The speed-up should be noticeable. Summary: - Fix arch build issues (hexagon, sh) - Clean up various Makefiles and scripts - Fix wrong usage of {CFLAGS,LDFLAGS}_MODULE in arch Makefiles - Cache variables that are expensive to compute - Improve cc-ldopton and ld-option for Clang - Optimize output directory creation" * tag 'kbuild-v4.15' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (30 commits) kbuild: move coccicheck help from scripts/Makefile.help to top Makefile sh: decompressor: add shipped files to .gitignore frv: .gitignore: ignore vmlinux.lds selinux: remove unnecessary assignment to subdir- kbuild: specify FORCE in Makefile.headersinst as .PHONY target kbuild: remove redundant mkdir from ./Kbuild kbuild: optimize object directory creation for incremental build kbuild: create object directories simpler and faster kbuild: filter-out PHONY targets from "targets" kbuild: remove redundant $(wildcard ...) for cmd_files calculation kbuild: create directory for make cache only when necessary sh: select KBUILD_DEFCONFIG depending on ARCH kbuild: fix linker feature test macros when cross compiling with Clang kbuild: shrink .cache.mk when it exceeds 1000 lines kbuild: do not call cc-option before KBUILD_CFLAGS initialization kbuild: Cache a few more calls to the compiler kbuild: Add a cache for generated variables kbuild: add forward declaration of default target to Makefile.asm-generic kbuild: remove KBUILD_SUBDIR_ASFLAGS and KBUILD_SUBDIR_CCFLAGS hexagon/kbuild: replace CFLAGS_MODULE with KBUILD_CFLAGS_MODULE ...
2017-11-02License cleanup: add SPDX GPL-2.0 license identifier to files with no licenseGreg Kroah-Hartman
Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-10-09kbuild: mkcompile_h: do not create .versionMasahiro Yamada
This script does not need to create .version; it will be created by scripts/link-vmlinux.sh later. Clean-up the code slightly. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2017-06-19scripts/mkcompile_h: Remove trailing spaces from compiler versionJonathan Liu
Improves the output of "cat /proc/version" by getting rid of the trailing space at the end of the compiler version when the kernel is compiled using GCC. Signed-off-by: Jonathan Liu <net147@gmail.com> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2014-04-30kbuild: trivial - remove trailing spacesMasahiro Yamada
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com> Signed-off-by: Michal Marek <mmarek@suse.cz>
2014-04-09kbuild: LLVMLinux: Fix LINUX_COMPILER definition script for compilation with ↵Jan-Simon Möller
clang When building the LINUX_COMPILER definition, instead of merely taking the last line from "$(CC) -v", grep for ' version ' in the output. This supports both gcc and clang. Signed-off-by: Jan-Simon Möller <dl9pf@gmx.de> Signed-off-by: Behan Webster <behanw@converseincode.com> Signed-off-by: Mark Charlebois <charlebm@gmail.com> Cc: PaX Team <pageexec@freemail.hu>
2011-04-29Fix handling of backlash character in LINUX_COMPILE_BY nameMarcin Nowakowski
When using a domain login, `whoami` returns the login in user\domain format. This leads to either warnings on unrecognised escape sequences or escaped characters being generated for the user. This patch ensures that any backslash is escaped to a double-backslash to make sure the name is preserved correctly. This patch does not enforce escaping on the KBUILD_BUILD_USER variable, as this is something the user has control of and can escape if required. Signed-off-by: Marcin Nowakowski <marcin.nowakowski.000@gmail.com> Signed-off-by: Michal Marek <mmarek@suse.cz>
2011-04-18kbuild: Allow to override LINUX_COMPILE_BY and LINUX_COMPILE_HOST macrosMichal Marek
Make it possible to override the user@host string displayed during boot and in /proc/version by the environment variables KBUILD_BUILD_USER and KBUILD_BUILD_HOST. Several distributions patch scripts/mkcompile_h to achieve this, so let's provide an official way. Also, document the KBUILD_BUILD_TIMESTAMP variable while at it. Signed-off-by: Michal Marek <mmarek@suse.cz>
2011-04-18kbuild: Drop unused LINUX_COMPILE_TIME and LINUX_COMPILE_DOMAIN macrosMichal Marek
Signed-off-by: Michal Marek <mmarek@suse.cz>
2010-02-02scripts/mkcompile_h: don't test for hardcoded pathsMichal Marek
Don't test for /bin/{dnsdomainname,domainname}, simply try to execute the command and check if it returned something. Reported-by: Glenn Sommer <glemsom@gmail.com> Acked-by: WANG Cong <xiyou.wangcong@gmail.com> Tested-by: Glenn Sommer <glemsom@gmail.com> Signed-off-by: Michal Marek <mmarek@suse.cz>
2009-12-12kbuild: move autoconf.h to include/generatedSam Ravnborg
Signed-off-by: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Michal Marek <mmarek@suse.cz>
2009-10-11kbuild: mkcompile_h: trivial cleanupsFelipe Contreras
UTS_TRUNCATTE is simpler this way, and now editors idetify this as a shell script. Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com> Acked-by: WANG Cong <xiyou.wangcong@gmail.com> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
2009-10-11kbuild: fix warning when domainname is not availableFelipe Contreras
Otherwise we get: "dnsdomainname: Unknown host" Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com> Acked-by: WANG Cong <xiyou.wangcong@gmail.com> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
2008-12-03kbuild: kill output in silent mode of mkcompile_hMike Frysinger
The mkcompile_h script does `echo` regardless of silent mode the make is running at, so have it respect $quiet from kbuild and only echo when not in silent mode. Signed-off-by: Mike Frysinger <vapier@gentoo.org> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
2007-05-02kbuild: override build timestamp & versionSam Ravnborg
Introduce KBUILD_BUILD_VERSION to make it possible to override kernel build version during build time. Introduce KBUILD_BUILD_TIMESTAMP to make it possible to override kernel build timestamp during build time. But variables are useful mainly by distros that want to pass info from an SCM when building the kernel. Timestamp could be last checkin date for a file etc. The idea came from Olaf Hering <olaf@aepfle.de> Cc: Olaf Hering <olaf@aepfle.de> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
2007-02-14[PATCH] Make mkcompile_h use LANG=C and LC_ALL=C for $CC -vs situert
Fix a minor bug in mkcompile_h. As one can see, the current locale is used while getting the version of gcc. This produces problems when a locale other than C or en_US is used. As an example, my /proc/version contains Turkish characters in iso-8859-9 encoding. This patch fixes this issue by making sure that the C locale is used to get gcc's version. Cc: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2005-07-14kbuild: "PREEMPT" in UTS_VERSIONSam Ravnborg
From: Matt Mackall <mpm@selenic.com> Add PREEMPT to UTS_VERSION where enabled as is done for SMP to make preempt kernels easily identifiable. Added SMP PREEMPT as comment in compile.h to force it to be updated when they change (sam). Signed-off-by: Matt Mackall <mpm@selenic.com> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
2005-04-16Linux-2.6.12-rc2Linus Torvalds
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!