Commit 40df759e2b ("kbuild: Fix build with binutils <= 2.19")
introduced ar-option and KBUILD_ARFLAGS to deal with old binutils.
According to Documentation/process/changes.rst, the current minimal
supported version of binutils is 2.21 so you can assume the 'D' option
is always supported. Not only GNU ar but also llvm-ar supports it.
With the 'D' option hard-coded, there is no more user of ar-option
or KBUILD_ARFLAGS.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Summary of modules changes for the 5.4 merge window:
- Introduce exported symbol namespaces.
This new feature allows subsystem maintainers to partition and
categorize their exported symbols into explicit namespaces. Module
authors are now required to import the namespaces they need.
Some of the main motivations of this feature include: allowing kernel
developers to better manage the export surface, allow subsystem
maintainers to explicitly state that usage of some exported symbols
should only be limited to certain users (think: inter-module or
inter-driver symbols, debugging symbols, etc), as well as more easily
limiting the availability of namespaced symbols to other parts of the
kernel. With the module import requirement, it is also easier to spot
the misuse of exported symbols during patch review. Two new macros are
introduced: EXPORT_SYMBOL_NS() and EXPORT_SYMBOL_NS_GPL(). The API is
thoroughly documented in Documentation/kbuild/namespaces.rst.
- Some small code and kbuild cleanups here and there.
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Merge tag 'modules-for-v5.4' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux
Pull modules updates from Jessica Yu:
"The main bulk of this pull request introduces a new exported symbol
namespaces feature. The number of exported symbols is increasingly
growing with each release (we're at about 31k exports as of 5.3-rc7)
and we currently have no way of visualizing how these symbols are
"clustered" or making sense of this huge export surface.
Namespacing exported symbols allows kernel developers to more
explicitly partition and categorize exported symbols, as well as more
easily limiting the availability of namespaced symbols to other parts
of the kernel. For starters, we have introduced the USB_STORAGE
namespace to demonstrate the API's usage. I have briefly summarized
the feature and its main motivations in the tag below.
Summary:
- Introduce exported symbol namespaces.
This new feature allows subsystem maintainers to partition and
categorize their exported symbols into explicit namespaces. Module
authors are now required to import the namespaces they need.
Some of the main motivations of this feature include: allowing
kernel developers to better manage the export surface, allow
subsystem maintainers to explicitly state that usage of some
exported symbols should only be limited to certain users (think:
inter-module or inter-driver symbols, debugging symbols, etc), as
well as more easily limiting the availability of namespaced symbols
to other parts of the kernel.
With the module import requirement, it is also easier to spot the
misuse of exported symbols during patch review.
Two new macros are introduced: EXPORT_SYMBOL_NS() and
EXPORT_SYMBOL_NS_GPL(). The API is thoroughly documented in
Documentation/kbuild/namespaces.rst.
- Some small code and kbuild cleanups here and there"
* tag 'modules-for-v5.4' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux:
module: Remove leftover '#undef' from export header
module: remove unneeded casts in cmp_name()
module: move CONFIG_UNUSED_SYMBOLS to the sub-menu of MODULES
module: remove redundant 'depends on MODULES'
module: Fix link failure due to invalid relocation on namespace offset
usb-storage: export symbols in USB_STORAGE namespace
usb-storage: remove single-use define for debugging
docs: Add documentation for Symbol Namespaces
scripts: Coccinelle script for namespace dependencies.
modpost: add support for generating namespace dependencies
export: allow definition default namespaces in Makefiles or sources
module: add config option MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS
modpost: add support for symbol namespaces
module: add support for symbol namespaces.
export: explicitly align struct kernel_symbol
module: support reading multiple values per modinfo tag
- add modpost warn exported symbols marked as 'static' because 'static'
and EXPORT_SYMBOL is an odd combination
- break the build early if gold linker is used
- optimize the Bison rule to produce .c and .h files by a single
pattern rule
- handle PREEMPT_RT in the module vermagic and UTS_VERSION
- warn CONFIG options leaked to the user-space except existing ones
- make single targets work properly
- rebuild modules when module linker scripts are updated
- split the module final link stage into scripts/Makefile.modfinal
- fix the missed error code in merge_config.sh
- improve the error message displayed on the attempt of the O= build
in unclean source tree
- remove 'clean-dirs' syntax
- disable -Wimplicit-fallthrough warning for Clang
- add CONFIG_CC_OPTIMIZE_FOR_SIZE_O3 for ARC
- remove ARCH_{CPP,A,C}FLAGS variables
- add $(BASH) to run bash scripts
- change *CFLAGS_<basetarget>.o to take the relative path to $(obj)
instead of the basename
- stop suppressing Clang's -Wunused-function warnings when W=1
- fix linux/export.h to avoid genksyms calculating CRC of trimmed
exported symbols
- misc cleanups
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Merge tag 'kbuild-v5.4' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild updates from Masahiro Yamada:
- add modpost warn exported symbols marked as 'static' because 'static'
and EXPORT_SYMBOL is an odd combination
- break the build early if gold linker is used
- optimize the Bison rule to produce .c and .h files by a single
pattern rule
- handle PREEMPT_RT in the module vermagic and UTS_VERSION
- warn CONFIG options leaked to the user-space except existing ones
- make single targets work properly
- rebuild modules when module linker scripts are updated
- split the module final link stage into scripts/Makefile.modfinal
- fix the missed error code in merge_config.sh
- improve the error message displayed on the attempt of the O= build in
unclean source tree
- remove 'clean-dirs' syntax
- disable -Wimplicit-fallthrough warning for Clang
- add CONFIG_CC_OPTIMIZE_FOR_SIZE_O3 for ARC
- remove ARCH_{CPP,A,C}FLAGS variables
- add $(BASH) to run bash scripts
- change *CFLAGS_<basetarget>.o to take the relative path to $(obj)
instead of the basename
- stop suppressing Clang's -Wunused-function warnings when W=1
- fix linux/export.h to avoid genksyms calculating CRC of trimmed
exported symbols
- misc cleanups
* tag 'kbuild-v5.4' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (63 commits)
genksyms: convert to SPDX License Identifier for lex.l and parse.y
modpost: use __section in the output to *.mod.c
modpost: use MODULE_INFO() for __module_depends
export.h, genksyms: do not make genksyms calculate CRC of trimmed symbols
export.h: remove defined(__KERNEL__), which is no longer needed
kbuild: allow Clang to find unused static inline functions for W=1 build
kbuild: rename KBUILD_ENABLE_EXTRA_GCC_CHECKS to KBUILD_EXTRA_WARN
kbuild: refactor scripts/Makefile.extrawarn
merge_config.sh: ignore unwanted grep errors
kbuild: change *FLAGS_<basetarget>.o to take the path relative to $(obj)
modpost: add NOFAIL to strndup
modpost: add guid_t type definition
kbuild: add $(BASH) to run scripts with bash-extension
kbuild: remove ARCH_{CPP,A,C}FLAGS
kbuild,arc: add CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3 for ARC
kbuild: Do not enable -Wimplicit-fallthrough for clang for now
kbuild: clean up subdir-ymn calculation in Makefile.clean
kbuild: remove unneeded '+' marker from cmd_clean
kbuild: remove clean-dirs syntax
kbuild: check clean srctree even earlier
...
- A bunch of DT binding conversions to DT schema format
- Clean-ups of the Arm idle-states binding
- Support a default number of cells in of_for_each_phandle() when the
cells name is missing
- Expose dtbs_check and dt_binding_check in the make help
- Convert writting-schema.md to ReST
- HiSilicon reset controller binding updates
- Add documentation for MT8516 RNG
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Merge tag 'devicetree-for-5.4' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux
Pull Devicetree updates from Rob Herring:
- a bunch of DT binding conversions to DT schema format
- clean-ups of the Arm idle-states binding
- support a default number of cells in of_for_each_phandle() when the
cells name is missing
- expose dtbs_check and dt_binding_check in the make help
- convert writting-schema.md to ReST
- HiSilicon reset controller binding updates
- add documentation for MT8516 RNG
* tag 'devicetree-for-5.4' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux: (46 commits)
of: restore old handling of cells_name=NULL in of_*_phandle_with_args()
bus: qcom: fix spelling mistake "ambigous" -> "ambiguous"
of: Let of_for_each_phandle fallback to non-negative cell_count
iommu: pass cell_count = -1 to of_for_each_phandle with cells_name
dt-bindings: arm: Convert Realtek board/soc bindings to json-schema
dt-bindings: arm: Convert Actions Semi bindings to jsonschema
dt-bindings: Correct spelling in example schema
dt-bindings: cpu: Add a support cpu type for cortex-a55
dt-bindings: gpu: mali-midgard: Add samsung exynos5250 compatible
dt-bindings: arm: idle-states: Move exit-latency-us explanation
dt-bindings: arm: idle-states: Add punctuation to improve readability
dt-bindings: arm: idle-states: Correct "constraint guarantees"
dt-bindings: arm: idle-states: Correct references to wake-up delay
dt-bindings: arm: idle-states: Use "e.g." and "i.e." consistently
pinctrl-mcp23s08: Fix property-name in dt-example
dt-bindings: Clarify interrupts-extended usage
dt-bindings: Convert Arm Mali Utgard GPU to DT schema
dt-bindings: Convert Arm Mali Bifrost GPU to DT schema
dt-bindings: Convert Arm Mali Midgard GPU to DT schema
dt-bindings: irq: Convert Allwinner NMI Controller to a schema
...
- 52-bit virtual addressing in the kernel
- New ABI to allow tagged user pointers to be dereferenced by syscalls
- Early RNG seeding by the bootloader
- Improve robustness of SMP boot
- Fix TLB invalidation in light of recent architectural clarifications
- Support for i.MX8 DDR PMU
- Remove direct LSE instruction patching in favour of static keys
- Function error injection using kprobes
- Support for the PPTT "thread" flag introduced by ACPI 6.3
- Move PSCI idle code into proper cpuidle driver
- Relaxation of implicit I/O memory barriers
- Build with RELR relocations when toolchain supports them
- Numerous cleanups and non-critical fixes
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Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 updates from Will Deacon:
"Although there isn't tonnes of code in terms of line count, there are
a fair few headline features which I've noted both in the tag and also
in the merge commits when I pulled everything together.
The part I'm most pleased with is that we had 35 contributors this
time around, which feels like a big jump from the usual small group of
core arm64 arch developers. Hopefully they all enjoyed it so much that
they'll continue to contribute, but we'll see.
It's probably worth highlighting that we've pulled in a branch from
the risc-v folks which moves our CPU topology code out to where it can
be shared with others.
Summary:
- 52-bit virtual addressing in the kernel
- New ABI to allow tagged user pointers to be dereferenced by
syscalls
- Early RNG seeding by the bootloader
- Improve robustness of SMP boot
- Fix TLB invalidation in light of recent architectural
clarifications
- Support for i.MX8 DDR PMU
- Remove direct LSE instruction patching in favour of static keys
- Function error injection using kprobes
- Support for the PPTT "thread" flag introduced by ACPI 6.3
- Move PSCI idle code into proper cpuidle driver
- Relaxation of implicit I/O memory barriers
- Build with RELR relocations when toolchain supports them
- Numerous cleanups and non-critical fixes"
* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (114 commits)
arm64: remove __iounmap
arm64: atomics: Use K constraint when toolchain appears to support it
arm64: atomics: Undefine internal macros after use
arm64: lse: Make ARM64_LSE_ATOMICS depend on JUMP_LABEL
arm64: asm: Kill 'asm/atomic_arch.h'
arm64: lse: Remove unused 'alt_lse' assembly macro
arm64: atomics: Remove atomic_ll_sc compilation unit
arm64: avoid using hard-coded registers for LSE atomics
arm64: atomics: avoid out-of-line ll/sc atomics
arm64: Use correct ll/sc atomic constraints
jump_label: Don't warn on __exit jump entries
docs/perf: Add documentation for the i.MX8 DDR PMU
perf/imx_ddr: Add support for AXI ID filtering
arm64: kpti: ensure patched kernel text is fetched from PoU
arm64: fix fixmap copy for 16K pages and 48-bit VA
perf/smmuv3: Validate groups for global filtering
perf/smmuv3: Validate group size
arm64: Relax Documentation/arm64/tagged-pointers.rst
arm64: kvm: Replace hardcoded '1' with SYS_PAR_EL1_F
arm64: mm: Ignore spurious translation faults taken from the kernel
...
A script that uses the '<module>.ns_deps' files generated by modpost to
automatically add the required symbol namespace dependencies to each
module.
Usage:
1) Move some symbols to a namespace with EXPORT_SYMBOL_NS() or define
DEFAULT_SYMBOL_NAMESPACE
2) Run 'make' (or 'make modules') and get warnings about modules not
importing that namespace.
3) Run 'make nsdeps' to automatically add required import statements
to said modules.
This makes it easer for subsystem maintainers to introduce and maintain
symbol namespaces into their codebase.
Co-developed-by: Martijn Coenen <maco@android.com>
Signed-off-by: Martijn Coenen <maco@android.com>
Acked-by: Julia Lawall <julia.lawall@lip6.fr>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Matthias Maennich <maennich@google.com>
Signed-off-by: Jessica Yu <jeyu@kernel.org>
This patch adds an option to modpost to generate a <module>.ns_deps file
per module, containing the namespace dependencies for that module.
E.g. if the linked module my-module.ko would depend on the symbol
myfunc.MY_NS in the namespace MY_NS, the my-module.ns_deps file created
by modpost would contain the entry MY_NS to express the namespace
dependency of my-module imposed by using the symbol myfunc.
These files can subsequently be used by static analysis tools (like
coccinelle scripts) to address issues with missing namespace imports. A
later patch of this series will introduce such a script 'nsdeps' and a
corresponding make target to automatically add missing
MODULE_IMPORT_NS() definitions to the module's sources. For that it uses
the information provided in the generated .ns_deps files.
Co-developed-by: Martijn Coenen <maco@android.com>
Signed-off-by: Martijn Coenen <maco@android.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Matthias Maennich <maennich@google.com>
Signed-off-by: Jessica Yu <jeyu@kernel.org>
KBUILD_ENABLE_EXTRA_GCC_CHECKS started as a switch to add extra warning
options for GCC, but now it is a historical misnomer since we use it
also for Clang, DTC, and even kernel-doc.
Rename it to more sensible, shorter KBUILD_EXTRA_WARN.
For the backward compatibility, KBUILD_ENABLE_EXTRA_GCC_CHECKS is still
supported (but not advertised in the documentation).
I also fixed up 'make help', and updated the documentation.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Sedat Dilek <sedat.dilek@gmail.com>
CONFIG_SHELL falls back to sh when bash is not installed on the system,
but nobody is testing such a case since bash is usually installed.
So, shell scripts invoked by CONFIG_SHELL are only tested with bash.
It makes it difficult to test whether the hashbang #!/bin/sh is real.
For example, #!/bin/sh in arch/powerpc/kernel/prom_init_check.sh is
false. (I fixed it up)
Besides, some shell scripts invoked by CONFIG_SHELL use bash-extension
and #!/bin/bash is specified as the hashbang, while CONFIG_SHELL may
not always be set to bash.
Probably, the right thing to do is to introduce BASH, which is bash by
default, and always set CONFIG_SHELL to sh. Replace $(CONFIG_SHELL)
with $(BASH) for bash scripts.
If somebody tries to add bash-extension to a #!/bin/sh script, it will
be caught in testing because /bin/sh is a symlink to dash on some major
distributions.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
These flags were added by commit 61754c1875 ("kbuild: Allow arch
Makefiles to override {cpp,ld,c}flags") to allow ARC to override -O2.
We did not see any other usage after all. Now that ARC switched to
CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3, there is no more user of
these variables.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
arch/arc/Makefile overrides -O2 with -O3. This is the only user of
ARCH_CFLAGS. There is no user of ARCH_CPPFLAGS or ARCH_AFLAGS.
My plan is to remove ARCH_{CPP,A,C}FLAGS after refactoring the ARC
Makefile.
Currently, ARC has no way to enable -Wmaybe-uninitialized because both
-O3 and -Os disable it. Enabling it will be useful for compile-testing.
This commit allows allmodconfig (, which defaults to -O2) to enable it.
Add CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y to all the defconfig files
in arch/arc/configs/ in order to keep the current config settings.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Vineet Gupta <vgupta@synopsys.com>
This functionally reverts commit bfd77145f3 ("Makefile: Convert
-Wimplicit-fallthrough=3 to just -Wimplicit-fallthrough for clang").
clang enabled support for -Wimplicit-fallthrough in C in r369414 [1],
which causes a lot of warnings when building the kernel for two reasons:
1. Clang does not support the /* fall through */ comments. There seems
to be a general consensus in the LLVM community that this is not
something they want to support. Joe Perches wrote a script to convert
all of the comments to a "fallthrough" keyword that will be added to
compiler_attributes.h [2] [3], which catches the vast majority of the
comments. There doesn't appear to be any consensus in the kernel
community when to do this conversion.
2. Clang and GCC disagree about falling through to final case statements
with no content or cases that simply break:
https://godbolt.org/z/c8csDu
This difference contributes at least 50 warnings in an allyesconfig
build for x86, not considering other architectures. This difference
will need to be discussed to see which compiler is right [4] [5].
[1]: 1e0affb6e5
[2]: https://lore.kernel.org/lkml/61ddbb86d5e68a15e24ccb06d9b399bbf5ce2da7.camel@perches.com/
[3]: https://lore.kernel.org/lkml/1d2830aadbe9d8151728a7df5b88528fc72a0095.1564549413.git.joe@perches.com/
[4]: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91432
[5]: https://github.com/ClangBuiltLinux/linux/issues/636
Given these two problems need discussion and coordination, do not enable
-Wimplicit-fallthrough with clang right now. Add a comment to explain
what is going on as well. This commit should be reverted once these two
issues are fully flushed out and resolved.
Suggested-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Acked-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Acked-by: Nick Desaulniers <ndesaulniers@google.com>
Acked-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Move the outputmakefile target to the leftmost in the prerequisite list
so that this is checked first. GNU Make processes the prerequisites
left to right.
GNU Make will keep to stick to this behavior, and it seems even
POSIX standard, according to this:
https://lists.gnu.org/archive/html/bug-make/2019-08/msg00030.html
The POSIX standard of make is available here:
https://pubs.opengroup.org/onlinepubs/9699919799/utilities/make.html
Of course, when the parallel option -j given, other targets will be run
simultaneously but it is nice to show the error as early as possible.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
If you try out-of-tree build with an unclean source tree, Kbuild
suggests to run make mrproper. The path to the source tree may be
shown with a relative path, for example, "make O=foo" emits the
following:
.. is not clean, please run 'make mrproper'
in the '..' directory.
This is somewhat confusing if you ran "make O=foo" in the source tree.
Using the absolute path will be clearer.
This commit changes the error message like follows:
***
*** The source tree is not clean, please run 'make mrproper'
*** in /absolute/path/to/linux
***
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Since commit 3a475b2166 ("kbuild: Inform user to pass ARCH= for make
mrproper"), if you try out-of-tree build with an unclean source tree,
it suggests to run 'make ARCH=<ARCH> mrproper'.
This looks odd when you are not cross-compiling the kernel. Show the
'ARCH=<ARCH>' part only when ARCH= was given from the command line.
If ARCH is the default (native build) or came from the environment,
it should simply suggest 'make mrproper' as before.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Commit 415008af32 ("docs-rst: convert lsm from DocBook to ReST")
stopped using if_changed_rule. There is no more users of if_changed*
for the doc targets. Hence, fixdep is unneeded. Remove the dependency
on scripts_basic.
All the doc targets are phony. The dependency on FORCE is not needed
either.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
This line contains $(MAKE), so Make knows that it will invoke sub-make
without help of the '+' marker.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
scripts/package/Makefile does not use $(obj) or $(src) at all.
It actually generates files and directories in the top of $(objtree).
I do not see much sense in descending into scripts/package/.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
I am not a big fan of the $(objtree)/ hack for clean-files/clean-dirs.
These are created in the top of $(objtree), so let's clean them up
from the top Makefile.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
I think splitting the modpost and linking modules into separate
Makefiles will be useful especially when more complex build steps
come in. The main motivation of this commit is to integrate the
proposed klp-convert feature cleanly.
I moved the logging 'Building modules, stage 2.' to Makefile.modpost
to avoid the code duplication although I do not know whether or not
this message is needed in the first place.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Currently, the timestamp of module linker scripts are not checked.
Add them to the dependency of modules so they are correctly rebuilt.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Currently, the single target build directly descends into the directory
of the target. For example,
$ make foo/bar/baz.o
... directly descends into foo/bar/.
On the other hand, the normal build usually descends one directory at
a time, i.e. descends into foo/, and then foo/bar/.
This difference causes some problems.
[1] miss subdir-asflags-y, subdir-ccflags-y in upper Makefiles
The options in subdir-{as,cc}flags-y take effect in the current
and its sub-directories. In other words, they are inherited
downward. In the example above, the single target will miss
subdir-{as,cc}flags-y if they are defined in foo/Makefile.
[2] could be built in a different directory
As Documentation/kbuild/modules.rst section 4.3 says, Kbuild can
handle files that are spread over several sub-directories.
The build rule of foo/bar/baz.o may not necessarily be specified in
foo/bar/Makefile. It might be specifies in foo/Makefile as follows:
[foo/Makefile]
obj-y := bar/baz.o
This often happens when a module is so big that its source files
are divided into sub-directories.
In this case, there is no Makefile in the foo/bar/ directory, yet
the single target descends into foo/bar/, then fails due to the
missing Makefile. You can still do 'make foo/bar/' for partial
building, but cannot do 'make foo/bar/baz.s'. I believe the single
target '%.s' is a useful feature for inspecting the compiler output.
Some modules work around this issue by putting an empty Makefile
in every sub-directory.
This commit fixes those problems by making the single target build
descend in the same way as the normal build does.
Another change is the single target build will observe the CONFIG
options. Previously, it allowed users to build the foo.o even when
the corresponding CONFIG_FOO is disabled:
obj-$(CONFIG_FOO) += foo.o
In the new behavior, the single target build will just fail and show
"No rule to make target ..." (or "Nothing to be done for ..." if the
stale object already exists, but cannot be updated).
The disadvantage of this commit is the build speed. Now that the
single target build visits every directory and parses lots of
Makefiles, it is slower than before. (But, I hope it will not be
too slow.)
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
The in-kernel build and external module build have similar code
for descending into sub-directories.
Factor out the code into the common place.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
There is no need to set 0 to variables such as config-targets,
mixed-targets, etc.
Unset instead of setting 0 in order to use 'ifdef' to test them.
I also renamed:
config-targets -> config-build
mixed-targets -> mixed-build
dot-config -> need-config
to clarify what we are doing.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
'make clean' descends into ./Kbuild, but does not clean anything
since everything is added to no-clean-files.
There is no need to descend to ./Kbuild in the first place.
We can drop the no-clean-files assignment.
With this, there is no more user of no-clean-files. I will keep it
for a while to see whether a new user will appear.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
'make /' is just an alias for 'make ./'; this builds all objects of an
external module, but skips the modpost stage.
I am not a big fan of 'make /' since it looks as if it were touching
the root directory of the system. I like 'make ./' better.
I do not know how many people are using it, but let's show a hint if
it is used. Also, move it close to the external module rules since
this only makes sense for external modules.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
$(objtree)/Module.symvers is not required for descending into
sub-directories. It is needed for the modpost stage.
Move the Module.symvers check to the right place.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
It wasn't obvious that this was a command to run based on 'make help',
so add it to the top-level help for devicetree builds. Also, add an
example to the documentation to show that db_binding_check can be run
with DT_SCHEMA_FILES= to only check one schema file instead of all of
them.
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: <linux-kbuild@vger.kernel.org>
Cc: <devicetree@vger.kernel.org>
Cc: <linux-doc@vger.kernel.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
[robh: fix-up due to .md to .rst conversion]
Signed-off-by: Rob Herring <robh@kernel.org>
A compilation -Wimplicit-fallthrough warning was enabled by commit
a035d552a9 ("Makefile: Globally enable fall-through warning")
Even though clang 10.0.0 does not currently support this warning without
a patch, clang currently does not support a value for this option.
Link: https://bugs.llvm.org/show_bug.cgi?id=39382
The gcc default for this warning is 3 so removing the =3 has no effect
for gcc and enables the warning for patched versions of clang.
Also remove the =3 from an existing use in a parisc Makefile:
arch/parisc/math-emu/Makefile
Signed-off-by: Joe Perches <joe@perches.com>
Reviewed-and-tested-by: Nathan Chancellor <natechancellor@gmail.com>
Cc: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
- revive single target %.ko
- do not create built-in.a where it is unneeded
- do not create modules.order where it is unneeded
- show a warning if subdir-y/m is used to visit a module Makefile
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Merge tag 'kbuild-fixes-v5.3-3' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild fixes from Masahiro Yamada:
- revive single target %.ko
- do not create built-in.a where it is unneeded
- do not create modules.order where it is unneeded
- show a warning if subdir-y/m is used to visit a module Makefile
* tag 'kbuild-fixes-v5.3-3' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
kbuild: show hint if subdir-y/m is used to visit module Makefile
kbuild: generate modules.order only in directories visited by obj-y/m
kbuild: fix false-positive need-builtin calculation
kbuild: revive single target %.ko
Since commit ff9b45c55b ("kbuild: modpost: read modules.order instead
of $(MODVERDIR)/*.mod"), a module is no longer built in the following
pattern:
[Makefile]
subdir-y := some-module
[some-module/Makefile]
obj-m := some-module.o
You cannot write Makefile this way in upstream because modules.order is
not correctly generated. subdir-y is used to descend to a sub-directory
that builds tools, device trees, etc.
For external modules, the modules order does not matter. So, the
Makefile above was known to work.
I believe the Makefile should be re-written as follows:
[Makefile]
obj-m := some-module/
[some-module/Makefile]
obj-m := some-module.o
However, people will have no idea if their Makefile suddenly stops
working. In fact, I received questions from multiple people.
Show a warning for a while if obj-m is specified in a Makefile visited
by subdir-y or subdir-m.
I touched the %/ rule to avoid false-positive warnings for the single
target.
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Tom Stonecypher <thomas.edwardx.stonecypher@intel.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Tested-by: Jan Kiszka <jan.kiszka@siemens.com>
I removed the single target %.ko in commit ff9b45c55b ("kbuild:
modpost: read modules.order instead of $(MODVERDIR)/*.mod") because
the modpost stage does not work reliably. For instance, the module
dependency, modversion, etc. do not work if we lack symbol information
from the other modules.
Yet, some people still want to build only one module in their interest,
and it may be still useful if it is used within those limitations.
Fixes: ff9b45c55b ("kbuild: modpost: read modules.order instead of $(MODVERDIR)/*.mod")
Reported-by: Don Brace <don.brace@microsemi.com>
Reported-by: Arend Van Spriel <arend.vanspriel@broadcom.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Define and export OBJSIZE variable for "size" tool from binutils to be
used in architecture specific Makefiles (naming the variable just "SIZE"
would be too risky). In particular this tool is useful to perform checks
that early boot code is not using bss section (which might have not been
zeroed yet or intersects with initrd or other files boot loader might
have put right after the linux kernel).
Link: http://lkml.kernel.org/r/patch-1.thread-2257a1.git-188f5a3d81d5.your-ad-here.call-01565088755-ext-5120@work.hours
Acked-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
RELR is a relocation packing format for relative relocations.
The format is described in a generic-abi proposal:
https://groups.google.com/d/topic/generic-abi/bX460iggiKg/discussion
The LLD linker can be instructed to pack relocations in the RELR
format by passing the flag --pack-dyn-relocs=relr.
This patch adds a new config option, CONFIG_RELR. Enabling this option
instructs the linker to pack vmlinux's relative relocations in the RELR
format, and causes the kernel to apply the relocations at startup along
with the RELA relocations. RELA relocations still need to be applied
because the linker will emit RELA relative relocations if they are
unrepresentable in the RELR format (i.e. address not a multiple of 2).
Enabling CONFIG_RELR reduces the size of a defconfig kernel image
with CONFIG_RANDOMIZE_BASE by 3.5MB/16% uncompressed, or 550KB/5%
compressed (lz4).
Signed-off-by: Peter Collingbourne <pcc@google.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Will Deacon <will@kernel.org>
CLANG_FLAGS is initialized by the following line:
CLANG_FLAGS := --target=$(notdir $(CROSS_COMPILE:%-=%))
..., which is run only when CROSS_COMPILE is set.
Some build targets (bindeb-pkg etc.) recurse to the top Makefile.
When you build the kernel with Clang but without CROSS_COMPILE,
the same compiler flags such as -no-integrated-as are accumulated
into CLANG_FLAGS.
If you run 'make CC=clang' and then 'make CC=clang bindeb-pkg',
Kbuild will recompile everything needlessly due to the build command
change.
Fix this by correctly initializing CLANG_FLAGS.
Fixes: 238bcbc4e0 ("kbuild: consolidate Clang compiler flags")
Cc: <stable@vger.kernel.org> # v5.0+
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Acked-by: Nick Desaulniers <ndesaulniers@google.com>
Now that all the fall-through warnings have been addressed in the
kernel, enable the fall-through warning globally.
Also, update the deprecated.rst file to include implicit fall-through
as 'deprecated' so people can be pointed to a single location for
justification.
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Marek <michal.lkml@markovi.net>
Cc: Kees Cook <keescook@chromium.org>
Cc: linux-kbuild@vger.kernel.org
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Masahiro Yamada
Linus Torvalds
Matthias Maennich
Nathan Chancellor
Stephen Boyd
Joe Perches
Vasily Gorbik
Peter Collingbourne
Gustavo A. R. Silva