When include/linux/export-internal.h is updated, .vmlinux.export.o
must be rebuilt, but it does not happen because its rule is hidden
behind scripts/link-vmlinux.sh.
Move it out of the shell script, so that Make can see the dependency
between vmlinux and .vmlinux.export.o.
Move the vmlinux rule to scripts/Makefile.vmlinux.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Do not build modules.builtin(.modinfo) as a side-effect of vmlinux.
There are no good reason to rebuild them just because any of vmlinux's
prerequistes (vmlinux.lds, .vmlinux.export.c, etc.) has been updated.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Every EXPORT_SYMBOL creates __kstrtab_* and __kstrtabns_*, which
consumes 15-20% of the kallsyms entries.
For example, on the system built from the x86_64 defconfig,
$ cat /proc/kallsyms | wc
129527 388581 5685465
$ cat /proc/kallsyms | grep __kstrtab | wc
23489 70467 1187932
We already ignore __crc_* symbols populated by EXPORT_SYMBOL, so it
should be fine to ignore __kstrtab_* and __kstrtabns_* as well.
This makes vmlinux a bit smaller.
$ size vmlinux.before vmlinux.after
text data bss dec hex filename
22785374 8559694 1413328 32758396 1f3da7c vmlinux.before
22785374 8137806 1413328 32336508 1ed6a7c vmlinux.after
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
This gets rid of the pipe operator connected with 'cat'.
Also use getopt_long() to parse the command line.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Now that kallsyms.c parses the output from mksysmap, some symbols have
already been dropped.
Move comments to scripts/mksysmap. Also, make the grep command readable.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
scripts/mksysmap internally runs ${NM} (dropping some symbols).
When CONFIG_KALLSYMS=y, mksysmap creates .tmp_System.map, but it is
almost the same as the output from the ${NM} invocation in kallsyms().
It is true scripts/mksysmap drops some symbols, but scripts/kallsyms.c
ignores more anyway.
Keep the mksysmap output as *.syms, and reuse it for kallsyms and
'cmp -s'. It saves one ${NM} invocation.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Since commit 7b4537199a ("kbuild: link symbol CRCs at final link,
removing CONFIG_MODULE_REL_CRCS"), __crc_* symbols never become
absolute.
Keep ignoring __crc_*, but update the comment.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Kbuild puts the objects listed in head-y at the head of vmlinux.
Conventionally, we do this for head*.S, which contains the kernel entry
point.
A counter approach is to control the section order by the linker script.
Actually, the code marked as __HEAD goes into the ".head.text" section,
which is placed before the normal ".text" section.
I do not know if both of them are needed. From the build system
perspective, head-y is not mandatory. If you can achieve the proper code
placement by the linker script only, it would be cleaner.
I collected the current head-y objects into head-object-list.txt. It is
a whitelist. My hope is it will be reduced in the long run.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
The objects placed at the head of vmlinux need special treatments:
- arch/$(SRCARCH)/Makefile adds them to head-y in order to place
them before other archives in the linker command line.
- arch/$(SRCARCH)/kernel/Makefile adds them to extra-y instead of
obj-y to avoid them going into built-in.a.
This commit gets rid of the latter.
Create vmlinux.a to collect all the objects that are unconditionally
linked to vmlinux. The objects listed in head-y are moved to the head
of vmlinux.a by using 'ar m'.
With this, arch/$(SRCARCH)/kernel/Makefile can consistently use obj-y
for builtin objects.
There is no *.o that is directly linked to vmlinux. Drop unneeded code
in scripts/clang-tools/gen_compile_commands.py.
$(AR) mPi needs 'T' to workaround the llvm-ar bug. The fix was suggested
by Nathan Chancellor [1].
[1]: https://lore.kernel.org/llvm/YyjjT5gQ2hGMH0ni@dev-arch.thelio-3990X/
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
Modpost generates .vmlinux.export.c and *.mod.c, which are prerequisites
of vmlinux and modules, respectively.
The modpost stage should be re-run when the modpost code is updated.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Currently, modpost is executed twice; first for vmlinux, second
for modules.
This commit merges them.
Current build flow
==================
1) build obj-y and obj-m objects
2) link vmlinux.o
3) modpost for vmlinux
4) link vmlinux
5) modpost for modules
6) link modules (*.ko)
The build steps 1) through 6) are serialized, that is, modules are
built after vmlinux. You do not get benefits of parallel builds when
scripts/link-vmlinux.sh is being run.
New build flow
==============
1) build obj-y and obj-m objects
2) link vmlinux.o
3) modpost for vmlinux and modules
4a) link vmlinux
4b) link modules (*.ko)
In the new build flow, modpost is invoked just once.
vmlinux and modules are built in parallel. One exception is
CONFIG_DEBUG_INFO_BTF_MODULES=y, where modules depend on vmlinux.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
Move the build rules of vmlinux.o out of scripts/link-vmlinux.sh to
clearly separate 1) pre-modpost, 2) modpost, 3) post-modpost stages.
This will make further refactoring possible.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
.vmlinux.objs is used by modpost, so scripts/Makefile.modpost is
a better place to generate it.
It is used only when CONFIG_MODVERSIONS=y. It should be guarded
by "ifdef CONFIG_MODVERSIONS".
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
Use the ordinary obj-y syntax to list subdirectories.
Note1:
Previously, the link order of lib-y depended on CONFIG_MODULES; lib-y
was linked before drivers-y when CONFIG_MODULES=y, otherwise after
drivers-y. This was a bug of commit 7273ad2b08 ("kbuild: link lib-y
objects to vmlinux forcibly when CONFIG_MODULES=y"), but it was not a
big deal after all. Now, all objects listed in lib-y are linked last,
irrespective of CONFIG_MODULES.
Note2:
Finally, the single target build in arch/*/lib/ works correctly. There was
a bug report about this. [1]
$ make ARCH=arm arch/arm/lib/findbit.o
CALL scripts/checksyscalls.sh
AS arch/arm/lib/findbit.o
[1]: https://lore.kernel.org/linux-kbuild/YvUQOwL6lD4%2F5%2FU6@shell.armlinux.org.uk/
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
Doing make V=1 binrpm-pkg results in:
Executing(%install): /bin/sh -e /var/tmp/rpm-tmp.EgV6qJ
+ umask 022
+ cd .
+ /bin/rm -rf /home/scgl/rpmbuild/BUILDROOT/kernel-6.0.0_rc5+-1.s390x
+ /bin/mkdir -p /home/scgl/rpmbuild/BUILDROOT
+ /bin/mkdir /home/scgl/rpmbuild/BUILDROOT/kernel-6.0.0_rc5+-1.s390x
+ mkdir -p /home/scgl/rpmbuild/BUILDROOT/kernel-6.0.0_rc5+-1.s390x/boot
+ make -f ./Makefile image_name
+ cp test -e include/generated/autoconf.h -a -e include/config/auto.conf || ( \ echo >&2; \ echo >&2 " ERROR: Kernel configuration is invalid."; \ echo >&2 " include/generated/autoconf.h or include/config/auto.conf are missing.";\ echo >&2 " Run 'make oldconfig && make prepare' on kernel src to fix it."; \ echo >&2 ; \ /bin/false) arch/s390/boot/bzImage /home/scgl/rpmbuild/BUILDROOT/kernel-6.0.0_rc5+-1.s390x/boot/vmlinuz-6.0.0-rc5+
cp: invalid option -- 'e'
Try 'cp --help' for more information.
error: Bad exit status from /var/tmp/rpm-tmp.EgV6qJ (%install)
Because the make call to get the image name is verbose and prints
additional information.
Fixes: 993bdde945 ("kbuild: add image_name to no-sync-config-targets")
Signed-off-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Remove unused function argument, and there is
no logic changes.
Signed-off-by: Zeng Heng <zengheng4@huawei.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
The single target build has a subtle bug for the combination for
an individual file and a subdirectory.
[1] 'make kernel/fork.i' builds only kernel/fork.i
$ make kernel/fork.i
CALL scripts/checksyscalls.sh
DESCEND objtool
CPP kernel/fork.i
[2] 'make kernel/' builds only under the kernel/ directory.
$ make kernel/
CALL scripts/checksyscalls.sh
DESCEND objtool
CC kernel/fork.o
CC kernel/exec_domain.o
[snip]
CC kernel/rseq.o
AR kernel/built-in.a
But, if you try to do [1] and [2] in a single command, you will get
only [1] with a weird log:
$ make kernel/fork.i kernel/
CALL scripts/checksyscalls.sh
DESCEND objtool
CPP kernel/fork.i
make[2]: Nothing to be done for 'kernel/'.
With 'make kernel/fork.i kernel/', you should get both [1] and [2].
Rewrite the single target build.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Remove the bash build dependency for those who otherwise do not
have it installed. This also provides a significant speedup:
$ make defconfig
$ make yes2modconfig
...
$ find . -name "*.o" | grep -v vmlinux | wc
3169 3169 89615
$ export NM=nm
$ time sh -c 'find . -name "*.o" | grep -v vmlinux | xargs -n1
./scripts/check-local-export'
Without patch:
0m15.90s real 0m12.17s user 0m05.28s system
With patch:
dash + nawk
0m02.16s real 0m02.92s user 0m00.34s system
dash + busybox awk
0m02.36s real 0m03.36s user 0m00.34s system
dash + gawk
0m02.07s real 0m03.26s user 0m00.32s system
bash + gawk
0m03.55s real 0m05.00s user 0m00.54s system
Signed-off-by: Owen Rafferty <owen@owenrafferty.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Minimize the scope of LC_ALL=C like before commit 87c94bfb8a ("kbuild:
override build timestamp & version").
Give LC_ALL=C to '$LD -v' to get the consistent version output, as commit
bcbcf50f52 ("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 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>
The AWK code was added to deduplicate modules.order in case $(obj-m)
contains the same module multiple times, but it is actually unneeded
since commit b2c8855491 ("kbuild: update modules.order only when
contained modules are updated").
The list is already deduplicated before being processed by AWK because
$^ is the deduplicated list of prerequisites.
(Please note the real-prereqs macro uses $^)
Yet, modules.order will contain duplication if two different Makefiles
build the same module:
foo/Makefile:
obj-m += bar/baz.o
foo/bar/Makefile:
obj-m += baz.o
However, the parallel builds cannot properly handle this case in the
first place. So, it is better to let it fail (as already done by
scripts/modules-check.sh).
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Masahiro Yamada
Nick Desaulniers
Janis Schoetterl-Glausch
Zeng Heng
Owen Rafferty