Revert "kbuild: Make scripts/compile.h when sh != bash"

This reverts commit [1] in the pre-git era.

I do not know what problem happened in the script when sh != bash
because there is no commit message.

Now that this script is much simpler than it used to be, let's revert
it, and let' see. (If this turns out to be problematic, fix the code
with proper commit description.)

[1]: https://git.kernel.org/pub/scm/linux/kernel/git/history/history.git/commit/?id=11acbbbb8a50f4de7dbe4bc1b5acc440dfe81810

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

scripts/mkcompile_h: move LC_ALL=C to '$LD -v'

Minimize the scope of LC_ALL=C like before commit 87c94bfb8ad3 ("kbuild:
override build timestamp & version").

Give LC_ALL=C to '$LD -v' to get the consistent version output, as commit
bcbcf50f5218 ("kbuild: fix ld-version.sh to not be affected by locale")
mentioned the LD version is affected by locale.

While I was here, I merged two sed invocations.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

kbuild: build init/built-in.a just once

Kbuild builds init/built-in.a twice; first during the ordinary
directory descending, second from scripts/link-vmlinux.sh.

We do this because UTS_VERSION contains the build version and the
timestamp. We cannot update it during the normal directory traversal
since we do not yet know if we need to update vmlinux. UTS_VERSION is
temporarily calculated, but omitted from the update check. Otherwise,
vmlinux would be rebuilt every time.

When Kbuild results in running link-vmlinux.sh, it increments the
version number in the .version file and takes the timestamp at that
time to really fix UTS_VERSION.

However, updating the same file twice is a footgun. To avoid nasty
timestamp issues, all build artifacts that depend on init/built-in.a
are atomically generated in link-vmlinux.sh, where some of them do not
need rebuilding.

To fix this issue, this commit changes as follows:

[1] Split UTS_VERSION out to include/generated/utsversion.h from
include/generated/compile.h

include/generated/utsversion.h is generated just before the
vmlinux link. It is generated under include/generated/ because
some decompressors (s390, x86) use UTS_VERSION.

[2] Split init_uts_ns and linux_banner out to init/version-timestamp.c
from init/version.c

init_uts_ns and linux_banner contain UTS_VERSION. During the ordinary
directory descending, they are compiled with __weak and used to
determine if vmlinux needs relinking. Just before the vmlinux link,
they are compiled without __weak to embed the real version and
timestamp.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

sched/preempt: Tell about PREEMPT_DYNAMIC on kernel headers

Displaying "PREEMPT" on kernel headers when CONFIG_PREEMPT_DYNAMIC=y
can be misleading for anybody involved in remote debugging because it
is then not guaranteed that there is an actual preemption behaviour. It
depends on default Kconfig or boot defined choices.

Therefore, tell about PREEMPT_DYNAMIC on static kernel headers and leave
the search for the actual preemption behaviour to browsing dmesg.

Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20220217111240.GA742892@lothringen

kbuild: mkcompile_h: consider timestamp if KBUILD_BUILD_TIMESTAMP is set

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>

kbuild: clean up ${quiet} checks in shell scripts

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>

kbuild: Use uname for LINUX_COMPILE_HOST detection

`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>

kbuild: use CONFIG_CC_VERSION_TEXT to construct LINUX_COMPILER macro

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>

kbuild: mkcompile_h: Include $LD version in /proc/version

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>

kbuild: remove the owner check in mkcompile_h

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>

mkcompile_h: use printf for LINUX_COMPILE_BY

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>

mkcompile_h: git rid of UTS_TRUNCATE from LINUX_COMPILE_{BY,HOST}

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>

Kbuild: Handle PREEMPT_RT for version string and magic

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>

kbuild: remove unnecessary in-subshell execution

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>

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

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>

kbuild: mkcompile_h: do not create .version

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>

scripts/mkcompile_h: Remove trailing spaces from compiler version

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>

kbuild: trivial - remove trailing spaces

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>

kbuild: LLVMLinux: Fix LINUX_COMPILER definition script for compilation with 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>

Fix handling of backlash character in LINUX_COMPILE_BY name

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>

kbuild: Allow to override LINUX_COMPILE_BY and LINUX_COMPILE_HOST macros

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>

kbuild: Drop unused LINUX_COMPILE_TIME and LINUX_COMPILE_DOMAIN macros

Signed-off-by: Michal Marek <mmarek@suse.cz>

scripts/mkcompile_h: don't test for hardcoded paths

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>

kbuild: move autoconf.h to include/generated

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Michal Marek <mmarek@suse.cz>

kbuild: mkcompile_h: trivial cleanups

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>

kbuild: fix warning when domainname is not available

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>

kbuild: kill output in silent mode of mkcompile_h

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>

kbuild: override build timestamp & version

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>

[PATCH] Make mkcompile_h use LANG=C and LC_ALL=C for $CC -v

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>

kbuild: "PREEMPT" in UTS_VERSION

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>

Linux-2.6.12-rc2

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!