scripts/nsdeps is written to take care of only in-tree modules.
Perhaps, this is not a bug, but just a design. At least,
Documentation/core-api/symbol-namespaces.rst focuses on in-tree modules.
Having said that, some people already tried nsdeps for external modules.
So, it would be nice to support it.
Reported-by: Steve French <smfrench@gmail.com>
Reported-by: Jessica Yu <jeyu@kernel.org>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Tested-by: Jessica Yu <jeyu@kernel.org>
Acked-by: Jessica Yu <jeyu@kernel.org>
Reviewed-by: Matthias Maennich <maennich@google.com>
Tested-by: Matthias Maennich <maennich@google.com>
The modpost, with the -d option given, generates per-module .ns_deps
files.
Kbuild generates per-module .mod files to carry module information.
This is convenient because Make handles multiple jobs in parallel
when the -j option is given.
On the other hand, the modpost always runs as a single thread.
I do not see a strong reason to produce separate .ns_deps files.
This commit changes the modpost to generate just one file,
modules.nsdeps, each line of which has the following format:
<module_name>: <list of missing namespaces>
Please note it contains *missing* namespaces instead of required ones.
So, modules.nsdeps is empty if the namespace dependency is all good.
This will work more efficiently because spatch will no longer process
already imported namespaces. I removed the '(if needed)' from the
nsdeps log since spatch is invoked only when needed.
This also solves the stale .ns_deps problem reported by Jessica Yu:
https://lkml.org/lkml/2019/10/28/467
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Tested-by: Jessica Yu <jeyu@kernel.org>
Acked-by: Jessica Yu <jeyu@kernel.org>
Reviewed-by: Matthias Maennich <maennich@google.com>
Tested-by: Matthias Maennich <maennich@google.com>
'make nsdeps' invokes the modpost three times at most; before linking
vmlinux, before building modules, and finally for generating .ns_deps
files. Running the modpost again and again is not efficient.
The last two can be unified. When the -d option is given, the modpost
still does the usual job, and in addition, generates .ns_deps files.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Tested-by: Matthias Maennich <maennich@google.com>
Reviewed-by: Matthias Maennich <maennich@google.com>
Since commit 040fcc819a ("kbuild: improved modversioning support for
external modules"), the external module build reads Module.symvers in
the directory of the module itself, then dumps symbols back into it.
It accumulates stale symbols in the file when you build an external
module incrementally.
The idea behind it was, as the commit log explained, you can copy
Modules.symvers from one module to another when you need to pass symbol
information between two modules. However, the manual copy of the file
sounds questionable to me, and containing stale symbols is a downside.
Some time later, commit 0d96fb20b7 ("kbuild: Add new Kbuild variable
KBUILD_EXTRA_SYMBOLS") introduced a saner approach.
So, this commit removes the former one. Going forward, the external
module build dumps symbols into Module.symvers to be carried via
KBUILD_EXTRA_SYMBOLS, but never reads it automatically.
With the -I option removed, there is no one to set the external_module
flag unless KBUILD_EXTRA_SYMBOLS is passed. Now the -i option does it
instead.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
When building external modules, $(objtree)/Module.symvers is scanned
for symbol information of vmlinux and in-tree modules.
Additionally, vmlinux is parsed if it exists in $(objtree)/.
This is totally redundant since all the necessary information is
contained in $(objtree)/Module.symvers.
Do not parse vmlinux at all for external module builds. This makes
sense because vmlinux is deleted by 'make clean'.
'make clean' leaves all the build artifacts for building external
modules. vmlinux is unneeded for that.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
The comment line "When building external modules ..." explains
the same thing as "Include the module's Makefile ..." a few lines
below.
The comment "they may be used when building the .mod.c file" is no
longer true; .mod.c file is compiled in scripts/Makefile.modfinal
since commit 9b9a3f20cb ("kbuild: split final module linking out
into Makefile.modfinal"). I still keep the code in case $(obj) or
$(src) is used in the external module Makefile.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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
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>
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>
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>
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>
Since commit ff9b45c55b ("kbuild: modpost: read modules.order instead
of $(MODVERDIR)/*.mod"), 'make vmlinux' emits a warning, like this:
$ make defconfig vmlinux
[ snip ]
LD vmlinux.o
cat: modules.order: No such file or directory
MODPOST vmlinux.o
MODINFO modules.builtin.modinfo
KSYM .tmp_kallsyms1.o
KSYM .tmp_kallsyms2.o
LD vmlinux
SORTEX vmlinux
SYSMAP System.map
When building only vmlinux, KBUILD_MODULES is not set. Hence, the
modules.order is not generated. For the vmlinux modpost, it is not
necessary at all.
Separate scripts/Makefile.modpost for the vmlinux/modules stages.
This works more efficiently because the vmlinux modpost does not
need to include .*.cmd files.
Fixes: ff9b45c55b ("kbuild: modpost: read modules.order instead of $(MODVERDIR)/*.mod")
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
__modpost is a phony target. The dependency on FORCE is pointless.
All the objects have been built in the previous stage, so the
dependency on the objects are not necessary either.
Count the number of modules in a more straightforward way.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
KBUILD_EXTRA_SYMBOLS makes sense only when building external modules.
Moreover, the modpost sets 'external_module' if the -e option is given.
I replaced $(patsubst %, -e %,...) with simpler $(addprefix -e,...)
while I was here.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
If a build rule fails, the .DELETE_ON_ERROR special target removes the
target, but does nothing for the .*.cmd file, which might be corrupted.
So, .*.cmd files should be included only when the corresponding targets
exist.
Commit 392885ee82 ("kbuild: let fixdep directly write to .*.cmd
files") missed to fix up this file.
Fixes: 392885ee82 ("kbuild: let fixdep directly write to .*.cmd")
Cc: <stable@vger.kernel.org> # v5.0+
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
While descending directories, Kbuild produces objects for modules,
but do not link final *.ko files; it is done in the modpost.
To keep track of modules, Kbuild creates a *.mod file in $(MODVERDIR)
for every module it is building. Some post-processing steps read the
necessary information from *.mod files. This avoids descending into
directories again. This mechanism was introduced in 2003 or so.
Later, commit 551559e13a ("kbuild: implement modules.order") added
modules.order. So, we can simply read it out to know all the modules
with directory paths. This is easier than parsing the first line of
*.mod files.
$(MODVERDIR) has a flat directory structure, that is, *.mod files
are named only with base names. This is based on the assumption that
the module name is unique across the tree. This assumption is really
fragile.
Stephen Rothwell reported a race condition caused by a module name
conflict:
https://lkml.org/lkml/2019/5/13/991
In parallel building, two different threads could write to the same
$(MODVERDIR)/*.mod simultaneously.
Non-unique module names are the source of all kind of troubles, hence
commit 3a48a91901 ("kbuild: check uniqueness of module names")
introduced a new checker script.
However, it is still fragile in the build system point of view because
this race happens before scripts/modules-check.sh is invoked. If it
happens again, the modpost will emit unclear error messages.
To fix this issue completely, create *.mod with full directory path
so that two threads never attempt to write to the same file.
$(MODVERDIR) is no longer needed.
Since modules with directory paths are listed in modules.order, Kbuild
is still able to find *.mod files without additional descending.
I also killed cmd_secanalysis; scripts/mod/sumversion.c computes MD4 hash
for modules with MODULE_VERSION(). When CONFIG_DEBUG_SECTION_MISMATCH=y,
it occurs not only in the modpost stage, but also during directory
descending, where sumversion.c may parse stale *.mod files. It would emit
'No such file or directory' warning when an object consisting a module is
renamed, or when a single-obj module is turned into a multi-obj module or
vice versa.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Nicolas Pitre <nico@fluxnic.net>
Towards the goal of removing MODVERDIR, read out modules.order to get
the list of modules to be processed. This is simpler than parsing *.mod
files in $(MODVERDIR).
For external modules, $(KBUILD_EXTMOD)/modules.order should be read.
I removed the single target %.ko from the top Makefile. To make sure
modpost works correctly, vmlinux and the other modules must be built.
You cannot build a particular .ko file alone.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Commit ea837f1c05 ("kbuild: make modpost processing configurable")
was intended to give KBUILD_MODPOST_WARN flexibility to be configurable.
Right now KBUILD_MODPOST_WARN gets just ignored when KBUILD_EXTMOD is
set which happens per default when building modules out of the tree.
This change gives the opportunity to define module build behaving also
in case of out of tree builds and default will become exit on error.
Errors which can be detected by the build should be trapped out of the box
there, unless somebody wants to notice broken stuff later at runtime.
As this patch changes the default behaving from warning to error,
users can consider to fix it for external module builds by:
- providing module symbol table via KBUILD_EXTRA_SYMBOLS for
modules which are dependent
- OR getting old behaving back by passing KBUILD_MODPOST_WARN to the build
Signed-off-by: Wladislav Wiebe <wladislav.wiebe@nokia.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Unless CONFIG_DEBUG_SECTION_MISMATCH is enabled, modpost only shows
the number of section mismatches.
If you want to know the symbols causing the issue, you need to rebuild
with CONFIG_DEBUG_SECTION_MISMATCH. It is tedious.
I think it is fine to show annoying warning when a new section mismatch
comes in.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
In Kbuild, if_changed and friends must have FORCE as a prerequisite.
Hence, $(filter-out FORCE,$^) or $(filter-out $(PHONY),$^) is a common
idiom to get the names of all the prerequisites except phony targets.
Add real-prereqs as a shorthand.
Note:
We cannot replace $(filter %.o,$^) in cmd_link_multi-m because $^ may
include auto-generated dependencies from the .*.cmd file when a single
object module is changed into a multi object module. Refer to commit
69ea912fda ("kbuild: remove unneeded link_multi_deps"). I added some
comment to avoid accidental breakage.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Rob Herring <robh@kernel.org>
Commit a0f97e06a4 ("kbuild: enable 'make CFLAGS=...' to add
additional options to CC") renamed CFLAGS to KBUILD_CFLAGS.
Commit 222d394d30 ("kbuild: enable 'make AFLAGS=...' to add
additional options to AS") renamed AFLAGS to KBUILD_AFLAGS.
Commit 06c5040cdb ("kbuild: enable 'make CPPFLAGS=...' to add
additional options to CPP") renamed CPPFLAGS to KBUILD_CPPFLAGS.
For some reason, LDFLAGS was not renamed.
Using a well-known variable like LDFLAGS may result in accidental
override of the variable.
Kbuild generally uses KBUILD_ prefixed variables for the internally
appended options, so here is one more conversion to sanitize the
naming convention.
I did not touch Makefiles under tools/ since the tools build system
is a different world.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Palmer Dabbelt <palmer@sifive.com>
The comment is the same as in the top-level Makefile.
Also, the comments contain typos:
- the .PHONY variable -> the PHONY variable
- se we can ... -> so we can ...
Instead of fixing the typos, just remove the duplicated comments.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
