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Commit cf4f21938e13 ("kbuild: Allow to specify composite modules
with modname-m") added modname-m support, but missed to update the
corresponding multi-objs-m & modname-multi definition.
Signed-off-by: Cao jin <caoj.fnst@cn.fujitsu.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Currently, KBUILD_MODNAME is defined only when $(modname) contains
just one word. If an object is shared among multiple modules,
undefined KBUILD_MODNAME could cause a build error. For example,
if CONFIG_DYNAMIC_DEBUG is enabled, any call of printk() populates
.modname, then fails to build due to undefined KBUILD_MODNAME.
Take the following code as an example:
obj-m += foo.o
obj-m += bar.o
foo-objs := foo-bar-common.o foo-only.o
bar-objs := foo-bar-common.o bar-only.o
In this case, there is room for argument what to define for
KBUILD_MODNAME when foo-bar-common.o is being compiled.
"foo", "bar", or what else?
One idea is to define colon-separated modules that share the object,
in this case, "bar:foo" (modules are sorted alphabetically by
$(sort ...)).
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Cao jin <caoj.fnst@cn.fujitsu.com>
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In the context ...
$(obj)/%.s: $(src)/%.c FORCE
$(call if_changed_dep,cc_s_c)
$(obj)/%.i: $(src)/%.c FORCE
$(call if_changed_dep,cpp_i_c)
$(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_dep) FORCE
$(call cmd,force_checksrc)
$(call if_changed_rule,cc_o_c)
$(obj)/%.lst: $(src)/%.c FORCE
$(call if_changed_dep,cc_lst_c)
'$*' returns the stem of the target (the part of '%'), so $(obj)/ has
already been ripped off.
$(subst $(obj)/,,$*.o) is the same as $*.o
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Cao jin <caoj.fnst@cn.fujitsu.com>
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stat(1) is not standardized and different implementations have their own
(conflicting) flags for querying the size of a file.
ls(1) provides the same information (value of st.st_size) in the 5th
column, except when the file is a character or block device. This output
is standardized[0]. The -n option turns on -l, which writes lines
formatted like
"%s %u %s %s %u %s %s\n", <file mode>, <number of links>,
<owner name>, <group name>, <size>, <date and time>,
<pathname>
but instead of writing the <owner name> and <group name>, it writes the
numeric owner and group IDs (this avoids /etc/passwd and /etc/group
lookups as well as potential field splitting issues).
The <size> field is specified as "the value that would be returned for
the file in the st_size field of struct stat".
To avoid duplicating logic in several locations in the tree, create
scripts/file-size.sh and update callers to use that instead of stat(1).
[0] http://pubs.opengroup.org/onlinepubs/9699919799/utilities/ls.html#tag_20_73_10
Signed-off-by: Michael Forney <forney@google.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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If CONFIG_TRIM_UNUSED_KSYMS is enabled and the kernel is built from
a pristine state, the vmlinux is linked twice.
[1] A user runs 'make'
[2] First build with empty autoksyms.h
[3] adjust_autoksyms.sh updates autoksyms.h and recurses 'make vmlinux'
--------(begin sub-make)--------
[4] Second build with new autoksyms.h
[5] link-vmlinux.sh is invoked because vmlinux is missing
---------(end sub-make)---------
[6] link-vmlinux.sh is invoked again despite vmlinux is up-to-date.
The reason of [6] is probably because Make already decided to update
vmlinux at the time of [2] because vmlinux was missing when Make
built up the dependency graph.
Because if_changed is implemented based on $?, this issue can be
narrowed down to how Make handles $?.
You can test it with the following simple code:
[Test Makefile]
A: B
@echo newer prerequisite: $?
cp B A
B: C
cp C B
touch A
[Result]
$ rm -f A B
$ touch C
$ make
cp C B
touch A
newer prerequisite: B
cp B A
Here, 'A' has been touched in the recipe of 'B'. So, the dependency
'A: B' has already been met before the recipe of 'A' is executed.
However, Make does not notice the fact that the recipe of 'B' also
updates 'A' as a side-effect.
The situation is similar in this case; the vmlinux has actually been
updated in the vmlinux_prereq target. Make cannot predict this, so
judges the vmlinux is old.
link-vmlinux.sh is costly, so it is better to not run it when unneeded.
Split CONFIG_TRIM_UNUSED_KSYMS recursion to a dedicated target.
The reason of commit 2441e78b1919 ("kbuild: better abstract vmlinux
sequential prerequisites") was to cater to CONFIG_BUILD_DOCSRC, but
it was later removed by commit 184892925118 ("samples: move blackfin
gptimers-example from Documentation").
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
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The idea of using fixdep was inspired by Kconfig, but autoksyms
belongs to a different group. So, I want to move those touched
files under include/config/ksym/ to include/ksym/.
The directory include/ksym/ can be removed by 'make clean' because
it is meaningless for the external module building.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
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The external module building does not need to parse this code because
KBUILD_MODULES is always set anyway.
Move this code inside the "ifeq ($(KBUILD_EXTMOD),) ... endif" block.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
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Commit d3fc425e819b ("kbuild: make sure autoksyms.h exists early")
moved the code that touches autoksyms.h to scripts/kconfig/Makefile
with obscure reason.
From Nicolas' comment [1], he did not seem to be sure about the root
cause.
I guess I figured it out, so here is a fix-up I think is more correct.
According to the error log in the original post [2], the build failed
in scripts/mod/devicetable-offsets.c
scripts/mod/Makefile is descended from scripts/Makefile, which is
invoked from the top-level Makefile by the 'scripts' target.
To build vmlinux and/or modules, Kbuild descend into $(vmlinux-dirs).
This depends on 'prepare' and 'scripts' as follows:
$(vmlinux-dirs): prepare scripts
Because there is no dependency between 'prepare' and 'scripts', the
parallel building can execute them simultaneously.
'prepare' depends on 'prepare1', which touched autoksyms.h, while
'scripts' descends into script/, then scripts/mod/, which needs
<generated/autoksyms.h> if CONFIG_TRIM_UNUSED_KSYMS. It was the
reason of the race.
I am not happy to have unrelated code in the Kconfig Makefile, so
getting it back to the top Makefile.
I removed the standalone test target because I want to use it to
create an empty autoksyms.h file. Here is a little improvement;
unnecessary autoksyms.h is not created when CONFIG_TRIM_UNUSED_KSYMS
is disabled.
[1] https://lkml.org/lkml/2016/11/30/734
[2] https://lkml.org/lkml/2016/11/30/531
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
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Just a trivial change to prepare for the next commit.
This target is still invisible from external module building.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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The comment mentions it creates autoksyms.h in case it is missing,
but the actual code touches it when it does exists.
The build system creates it anyway because <linux/export.h> and
<asm-generic/export.h> need it.
The code would not have worked as intended, and people have not
noticed it. This is a proof that we can simply remove it.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
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Currently LDFLAGS is not cleared, so same flags are accumulated in
LDFLAGS when the top Makefile is recursively invoked.
I found unneeded rebuild for ARCH=arm64 when CONFIG_TRIM_UNUSED_KSYMS
is enabled. If include/generated/autoksyms.h is updated, the top
Makefile is recursively invoked, then arch/arm64/Makefile adds one
more '-maarch64linux'. Due to the command line change, modules are
rebuilt needlessly.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
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Documentation/kbuild/makefiles.txt lists variables used in Makefile
whereas Documentation/kbuild/kbuild.txt describes user assignable
parameters given via environments or the command line.
The top Makefile and arch/*/Makefile accumulate proper linker flags to
LDFLAGS_vmlinux. So, users can not override it from the command line.
Generally, per-file options are not supposed to be user-assignable.
Remove the misleading entry from kbuild.txt.
If we need a way to append user-specific flags for linking the kernel,
LDFLAGS_KERNEL would be a consistent choice because we already expose
LDFLAGS_MODULE counter-part to users.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Documentation/kbuild/makefiles.txt lists variables used in Makefile
whereas Documentation/kbuild/kbuild.txt describes user assignable
parameters given via environments or the command line.
LDFLAGS_MODULE is a command line interface, so it should be dropped
from makefiles.txt.
Some lines below in this file, it is clearly explained that
KBUILD_LDFLAGS_MODULE is the right one for the internal use:
KBUILD_LDFLAGS_MODULE Options for $(LD) when linking modules
$(KBUILD_LDFLAGS_MODULE) is used to add arch-specific options
used when linking modules. This is often a linker script.
From commandline LDFLAGS_MODULE shall be used (see kbuild.txt).
Then, kbuild.txt explains LDFLAGS_MODULE, like follows:
LDFLAGS_MODULE
--------------------------------------------------
Additional options used for $(LD) when linking modules.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Currently, linker options are tested by the coordination of $(CC) and
$(LD) because $(LD) needs some object to link.
As commit 86a9df597cdd ("kbuild: fix linker feature test macros when
cross compiling with Clang") addressed, we need to make sure $(CC)
and $(LD) agree the underlying architecture of the passed object.
This could be a bit complex when we combine tools from different groups.
For example, we can use clang for $(CC), but we still need to rely on
GCC toolchain for $(LD).
So, I was searching for a way of standalone testing of linker options.
A trick I found is to use '-v'; this not only prints the version string,
but also tests if the given option is recognized.
If a given option is supported,
$ aarch64-linux-gnu-ld -v --fix-cortex-a53-843419
GNU ld (Linaro_Binutils-2017.11) 2.28.2.20170706
$ echo $?
0
If unsupported,
$ aarch64-linux-gnu-ld -v --fix-cortex-a53-843419
GNU ld (crosstool-NG linaro-1.13.1-4.7-2013.04-20130415 - Linaro GCC 2013.04) 2.23.1
aarch64-linux-gnu-ld: unrecognized option '--fix-cortex-a53-843419'
aarch64-linux-gnu-ld: use the --help option for usage information
$ echo $?
1
Gold works likewise.
$ aarch64-linux-gnu-ld.gold -v --fix-cortex-a53-843419
GNU gold (Linaro_Binutils-2017.11 2.28.2.20170706) 1.14
masahiro@pug:~/ref/linux$ echo $?
0
$ aarch64-linux-gnu-ld.gold -v --fix-cortex-a53-999999
GNU gold (Linaro_Binutils-2017.11 2.28.2.20170706) 1.14
aarch64-linux-gnu-ld.gold: --fix-cortex-a53-999999: unknown option
aarch64-linux-gnu-ld.gold: use the --help option for usage information
$ echo $?
1
LLD too.
$ ld.lld -v --gc-sections
LLD 7.0.0 (http://llvm.org/git/lld.git 4a0e4190e74cea19f8a8dc625ccaebdf8b5d1585) (compatible with GNU linkers)
$ echo $?
0
$ ld.lld -v --fix-cortex-a53-843419
LLD 7.0.0 (http://llvm.org/git/lld.git 4a0e4190e74cea19f8a8dc625ccaebdf8b5d1585) (compatible with GNU linkers)
$ echo $?
0
$ ld.lld -v --fix-cortex-a53-999999
ld.lld: error: unknown argument: --fix-cortex-a53-999999
LLD 7.0.0 (http://llvm.org/git/lld.git 4a0e4190e74cea19f8a8dc625ccaebdf8b5d1585) (compatible with GNU linkers)
$ echo $?
1
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
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Support parallel building of clean, config, and build targets in a
single command.
For example,
make -j<N> clean all
or
make -j<N> mrproper defconfig all
They should be handled one by one.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Incremental linking is gone, so rename built-in.o to built-in.a, which
is the usual extension for archive files.
This patch does two things, first is a simple search/replace:
git grep -l 'built-in\.o' | xargs sed -i 's/built-in\.o/built-in\.a/g'
The second is to invert nesting of nested text manipulations to avoid
filtering built-in.a out from libs-y2:
-libs-y2 := $(filter-out %.a, $(patsubst %/, %/built-in.a, $(libs-y)))
+libs-y2 := $(patsubst %/, %/built-in.a, $(filter-out %.a, $(libs-y)))
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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This removes the old `ld -r` incremental link option, which has not
been selected by any architecture since June 2017.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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* Use BREs where EREs aren't necessary.
* Pass -E instead of -r to use EREs. This will be standardized in the
next POSIX revision[0]. GNU sed supports this since 4.2 (May 2009),
and busybox since 1.22.0 (Jan 2014).
* Use the [:space:] character class instead of ` \t` in bracket
expressions. In bracket expressions, POSIX says that <backslash> loses
its special meaning, so a conforming implementation cannot expand \t
to <tab>[1].
* In BREs, use interval expressions (\{n,m\}) instead of non-standard
features like \+ and \?.
* Use a loop instead of -s flag.
There are still plenty of other cases of non-standard sed invocations
(use of ERE features in BREs, in-place editing), but this fixes some
core ones.
[0] http://austingroupbugs.net/view.php?id=528
[1] http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap09.html#tag_09_03_05
Signed-off-by: Michael Forney <forney@google.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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