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  1. 09 7月, 2019 4 次提交
    • M
      kheaders: include only headers into kheaders_data.tar.xz · 7199ff7d
      由 Masahiro Yamada 提交于 
      Currently, kheaders_data.tar.xz contains some build scripts as well as
headers. None of them is needed in the header archive.

For ARCH=x86, this commit excludes the following from the archive:

  arch/x86/include/asm/Kbuild
  arch/x86/include/uapi/asm/Kbuild
  include/asm-generic/Kbuild
  include/config/auto.conf
  include/config/kernel.release
  include/config/tristate.conf
  include/uapi/asm-generic/Kbuild
  include/uapi/Kbuild
  kernel/gen_kheaders.sh

This change is actually motivated for the planned header compile-testing
because it will generate more build artifacts, which should not be
included in the archive.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: NJoel Fernandes (Google) <joel@joelfernandes.org>
      7199ff7d
    • M
      kheaders: remove meaningless -R option of 'ls' · b60b7c2e
      由 Masahiro Yamada 提交于 
      The -R option of 'ls' is supposed to be used for directories.

   -R, --recursive
          list subdirectories recursively

Since 'find ... -type f' only matches to regular files, we do not
expect directories passed to the 'ls' command here.

Giving -R is harmless at least, but unneeded.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: NJoel Fernandes (Google) <joel@joelfernandes.org>
      b60b7c2e
    • M
      kbuild: support header-test-pattern-y · 1e21cbfa
      由 Masahiro Yamada 提交于 
      In my view, most of headers can be self-contained. So, it would be
tedious to add every header to header-test-y explicitly. We usually
end up with "all headers with some exceptions".

There are two types in exceptions:

[1] headers that are never compiled as standalone units

  For examples, include/linux/compiler-gcc.h is not intended for
  direct inclusion. We should always exclude such ones.

[2] headers that are conditionally compiled as standalone units

  Some headers can be compiled only for particular architectures.
  For example, include/linux/arm-cci.h can be compiled only for
  arm/arm64 because it requires <asm/arm-cci.h> to exist.
  Clang can compile include/soc/nps/mtm.h only for arc because
  it contains an arch-specific register in inline assembler.

So, you can write Makefile like this:

  header-test-                += linux/compiler-gcc.h
  header-test-$(CONFIG_ARM)   += linux/arm-cci.h
  header-test-$(CONFIG_ARM64) += linux/arm-cci.h
  header-test-$(CONFIG_ARC)   += soc/nps/mtm.h

The new syntax header-test-pattern-y will be useful to specify
"the rest".

The typical usage is like this:

  header-test-pattern-y += */*.h

This will add all the headers in sub-directories to the test coverage,
excluding $(header-test-). In this regards, header-test-pattern-y
behaves like a weaker variant of header-test-y.

Caveat:
The patterns in header-test-pattern-y are prefixed with $(srctree)/$(src)/
but not $(objtree)/$(obj)/. Stale generated headers are often left over
when you traverse the git history without cleaning. Wildcard patterns for
$(objtree) may match to stale headers, which could fail to compile.
One pitfall is $(srctree)/$(src)/ and $(objtree)/$(obj)/ point to the
same directory for in-tree building. So, header-test-pattern-y should
be used with care since it can potentially match to stale headers.

Caveat2:
You could use wildcard for header-test-. For example,

  header-test- += asm-generic/%

... will exclude headers in asm-generic directory. Unfortunately, the
wildcard character is '%' instead of '*' here because this is evaluated
by $(filter-out ...) whereas header-test-pattern-y is evaluated by
$(wildcard ...). This is a kludge, but seems useful in some places...
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Tested-by: NJani Nikula <jani.nikula@intel.com>
      1e21cbfa
    • M
      kbuild: do not create wrappers for header-test-y · c93a0368
      由 Masahiro Yamada 提交于 
      header-test-y does not work with headers in sub-directories.

For example, you may want to write a Makefile, like this:

include/linux/Kbuild:

  header-test-y += mtd/nand.h

This entry will create a wrapper include/linux/mtd/nand.hdrtest.c
with the following content:

  #include "mtd/nand.h"

To make this work, we need to add $(srctree)/include/linux to the
header search path. It would be tedious to add ccflags-y.

Instead, we could change the *.hdrtest.c rule to wrap:

  #include "nand.h"

This works for in-tree build since #include "..." searches in the
relative path from the header with this directive. For O=... build,
we need to add $(srctree)/include/linux/mtd to the header search path,
which will be even more tedious.

After all, I thought it would be handier to compile headers directly
without creating wrappers.

I added a new build rule to compile %.h into %.h.s

The target is %.h.s instead of %.h.o because it is slightly faster.
Also, as for GCC, an empty assembly is smaller than an empty object.

I wrote the build rule:

  $(CC) $(c_flags) -S -o $@ -x c /dev/null -include $<

instead of:

  $(CC) $(c_flags) -S -o $@ -x c $<

Both work fine with GCC, but the latter is bad for Clang.

This comes down to the difference in the -Wunused-function policy.
GCC does not warn about unused 'static inline' functions at all.
Clang does not warn about the ones in included headers, but does
about the ones in the source. So, we should handle headers as
headers, not as source files.

In fact, this has been hidden since commit abb2ea7d ("compiler,
clang: suppress warning for unused static inline functions"), but we
should not rely on that.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: NJani Nikula <jani.nikula@intel.com>
Tested-by: NJani Nikula <jani.nikula@intel.com>
      c93a0368
  3. 08 7月, 2019 8 次提交
  5. 04 7月, 2019 1 次提交
  7. 01 7月, 2019 6 次提交
    • M
      fixdep: check return value of printf() and putchar() · 6f9ac9f4
      由 Masahiro Yamada 提交于 
      When there is not enough space on your storage device, the build will
fail with 'No space left on device' error message.

The reason is obvious from the message, so you will free up some disk
space, then you will resume the build.

However, sometimes you may still see a mysterious error message:

  unterminated call to function 'wildcard': missing ')'.

If you run out of the disk space, fixdep may end up with generating
incomplete .*.cmd files.

For example, if the disk-full error occurs while fixdep is running
print_dep(), the .*.cmd might be truncated like this:

   $(wildcard include/config/

When you run 'make' next time, this broken .*.cmd will be included,
then Make will terminate parsing since it is a wrong syntax.

Once this happens, you need to run 'make clean' or delete the broken
.*.cmd file manually.

Even if you do not see any error message, the .*.cmd files after any
error could be potentially incomplete, and unreliable. You may miss
the re-compilation due to missing header dependency.

If printf() cannot output the string for disk shortage or whatever
reason, it returns a negative value, but currently fixdep does not
check it at all. Consequently, fixdep *successfully* generates a
broken .*.cmd file. Make never notices that since fixdep exits with 0,
which means success.

Given the intended usage of fixdep, it must respect the return value
of not only malloc(), but also printf() and putchar().

This seems a long-standing issue since the introduction of fixdep.

In old days, Kbuild tried to provide an extra safety by letting fixdep
output to a temporary file and renaming it after everything is done:

  scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(dot-target).tmp;\
  rm -f $(depfile);                                                    \
  mv -f $(dot-target).tmp $(dot-target).cmd)

It was no help to avoid the current issue; fixdep successfully created
a truncated tmp file, which would be renamed to a .*.cmd file.

This problem should be fixed by propagating the error status to the
build system because:

[1] Since commit 9c2af1c7 ("kbuild: add .DELETE_ON_ERROR special
    target"), Make will delete the target automatically on any failure
    in the recipe.

[2] Since commit 392885ee ("kbuild: let fixdep directly write to
    .*.cmd files"), .*.cmd file is included only when the corresponding
    target already exists.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
      6f9ac9f4
    • M
      kbuild: split modules.order build rule out of 'modules' target · 68980b47
      由 Masahiro Yamada 提交于 
      modules.order is a real target. Split its build rule out like
modules.builtin
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
      68980b47
    • M
      kbuild: fix missed rebuild of modules.builtin · 50ef0cdf
      由 Masahiro Yamada 提交于 
      Unlike modules.order, modules.builtin is not rebuilt every time.
Once modules.builtin is created, it will not be updated until
auto.conf or tristate.conf is changed.

So, it does not  notice a change in Makefile, for example, the rename
of modules.

Kbuild must always descend into directories for modules.builtin too.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
      50ef0cdf
    • M
      kbuild: save $(strip ...) for calling if_changed and friends · c2341e2a
      由 Masahiro Yamada 提交于 
      The string returned by $(filter-out ...) does not contain any leading
or trailing spaces.

With the previous commit, 'any-prereq' no longer contains any
excessive spaces.

Nor does 'cmd-check' since it expands to a $(filter-out ...) call.

So, only the space that matters is the one between 'any-prereq'
and 'cmd-check'.

By removing it from the code, we can save $(strip ...) evaluation.
This refactoring is possible because $(any-prereq)$(cmd-check) is only
passed to the first argument of $(if ...), so we are only interested
in whether or not it is empty.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
      c2341e2a
    • M
      kbuild: save $(strip ...) for calling any-prepreq · 93f31bbd
      由 Masahiro Yamada 提交于 
      The string returned by $(filter-out ...) does not contain any leading
or trailing spaces.

So, only the space that matters is the one between

  $(filter-out $(PHONY),$?)

and

  $(filter-out $(PHONY) $(wildcard $^),$^)

By removing it from the code, we can save $(strip ...) evaluation.
This refactoring is possible because $(any-prereq) is only passed to
the first argument of $(if ...), so we are only interested in whether
or not it is empty.

This is also the prerequisite for the next commit.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
      93f31bbd
    • M
      kbuild: rename arg-check to cmd-check · 50bcca6a
      由 Masahiro Yamada 提交于 
      I prefer 'cmd-check' for consistency.

We have 'echo-cmd', 'cmd', 'cmd_and_fixdep', etc. in this file.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
      50bcca6a
  9. 24 6月, 2019 7 次提交
  11. 15 6月, 2019 13 次提交
    • J
      kbuild: add support for ensuring headers are self-contained · e846f0dc
      由 Jani Nikula 提交于 
      Sometimes it's useful to be able to explicitly ensure certain headers
remain self-contained, i.e. that they are compilable as standalone
units, by including and/or forward declaring everything they depend on.

Add special target header-test-y where individual Makefiles can add
headers to be tested if CONFIG_HEADER_TEST is enabled. This will
generate a dummy C file per header that gets built as part of extra-y.
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Reviewed-by: NSam Ravnborg <sam@ravnborg.org>
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
      e846f0dc
    • M
      kbuild: deb-pkg: do not run headers_check · 0315bb7a
      由 Masahiro Yamada 提交于 
      It is absolutely fine to add extra sanity checks in package scripts,
but it is not necessary to do so.

This is already covered by the daily compile-testing (0day bot etc.)
because headers_check is run as a part of the normal build process
when CONFIG_HEADERS_CHECK=y.

Replace it with the newly-added "make headers".
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
      0315bb7a
    • M
      kbuild: simplify scripts/headers_install.sh · 555187a8
      由 Masahiro Yamada 提交于 
      Now that headers_install.sh is invoked per file, remove the for-loop
in the shell script.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
      555187a8
    • M
      kbuild: move hdr-inst shorthand to top Makefile · a5bae54c
      由 Masahiro Yamada 提交于 
      Now that hdr-inst is used only in the top Makefile, move it there
from scripts/Kbuild.include.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
      a5bae54c
    • M
      kbuild: re-implement Makefile.headersinst without recursion · d5470d14
      由 Masahiro Yamada 提交于 
      Since commit fcc8487d ("uapi: export all headers under uapi
directories"), the headers in uapi directories are all exported by
default although exceptional cases are still allowed by the syntax
'no-export-headers'.

The traditional directory descending has been kept (in a somewhat
hacky way), but it is actually unneeded.

Get rid of it to simplify the code.

Also, handle files one by one instead of the previous per-directory
processing. This will emit much more log, but I like it.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
      d5470d14
    • M
      kbuild: add 'headers' target to build up uapi headers in usr/include · 59b2bd05
      由 Masahiro Yamada 提交于 
      In Linux build system, build targets and installation targets are
separated.

Examples are:

 - 'make vmlinux' -> 'make install'
 - 'make modules' -> 'make modules_install'
 - 'make dtbs'    -> 'make dtbs_install'
 - 'make vdso'    -> 'make vdso_install'

The intention is to run the build targets under the normal privilege,
then the installation targets under the root privilege since we need
the write permission to the system directories.

We have 'make headers_install' but the corresponding 'make headers'
stage does not exist. The purpose of headers_install is to provide
the kernel interface to C library. So, nobody would try to install
headers to /usr/include directly.

If 'sudo make INSTALL_HDR_PATH=/usr/include headers_install' were run,
some build artifacts in the kernel tree would be owned by root because
some of uapi headers are generated by 'uapi-asm-generic', 'archheaders'
targets.

Anyway, I believe it makes sense to split the header installation into
two stages.

 [1] 'make headers'
    Process headers in uapi directories by scripts/headers_install.sh
    and copy them to usr/include

 [2] 'make headers_install'
    Copy '*.h' verbatim from usr/include to $(INSTALL_HDR_PATH)/include

For the backward compatibility, 'headers_install' depends on 'headers'.

Some samples expect uapi headers in usr/include. So, the 'headers'
target is useful to build up them in the fixed location usr/include
irrespective of INSTALL_HDR_PATH.

Another benefit is to stop polluting the final destination with the
time-stamp files '.install' and '.check'. Maybe you can see them in
your toolchains.

Lastly, my main motivation is to prepare for compile-testing uapi
headers. To build something, we have to save an object and .*.cmd
somewhere. The usr/include/ will be the work directory for that.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
      59b2bd05
    • M
      kbuild: build all prerequisites of headers_install simultaneously · bdd7714b
      由 Masahiro Yamada 提交于 
      Currently, scripts/unifdef is compiled after scripts_basic,
uapi-asm-generic, archheaders, and archscripts.

The proper dependency is just scripts_basic. There is no problem
to compile scripts/unifdef and other headers at the same time.

Split scripts_unifdef out in order to allow more parallel building.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
      bdd7714b
    • M
      kbuild: remove build_unifdef target in scripts/Makefile · 2b8481be
      由 Masahiro Yamada 提交于 
      Since commit 2aedcd09 ("kbuild: suppress annoying "... is up to date."
message"), if_changed and friends nicely suppress "is up to date" messages.

We do not need per-Makefile tricks.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
      2b8481be
    • M
      kbuild: add CONFIG_HEADERS_INSTALL and loosen the dependency of samples · e949f4c2
      由 Masahiro Yamada 提交于 
      Commit 5318321d ("samples: disable CONFIG_SAMPLES for UML") used
a big hammer to fix the build errors under the samples/ directory.
Only some samples actually include uapi headers from usr/include.

Introduce CONFIG_HEADERS_INSTALL since 'depends on HEADERS_INSTALL' is
clearer than 'depends on !UML'. If this option is enabled, uapi headers
are installed before starting directory descending.

I added 'depends on HEADERS_INSTALL' to per-sample CONFIG options.
This allows UML to compile some samples.

$ make ARCH=um allmodconfig samples/
  [ snip ]
  CC [M]  samples/configfs/configfs_sample.o
  CC [M]  samples/kfifo/bytestream-example.o
  CC [M]  samples/kfifo/dma-example.o
  CC [M]  samples/kfifo/inttype-example.o
  CC [M]  samples/kfifo/record-example.o
  CC [M]  samples/kobject/kobject-example.o
  CC [M]  samples/kobject/kset-example.o
  CC [M]  samples/trace_events/trace-events-sample.o
  CC [M]  samples/trace_printk/trace-printk.o
  AR      samples/vfio-mdev/built-in.a
  AR      samples/built-in.a
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
      e949f4c2
    • M
      kbuild: fix Kconfig prompt of CONFIG_HEADERS_CHECK · c6509a24
      由 Masahiro Yamada 提交于 
      Prior to commit 257edce6 ("kbuild: exploit parallel building for
CONFIG_HEADERS_CHECK"), the sanity check of exported headers was done
as a side-effect of build rule of vmlinux.

That commit is good, but I missed to update the prompt of the Kconfig
entry. For the sake of preciseness, lets' say "when building 'all'".
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
      c6509a24
    • M
      kbuild: make gdb_script depend on prepare0 instead of prepare · 7a739ce5
      由 Masahiro Yamada 提交于 
      'gdb_script' needs headers generated by ./Kbuild, which is visited
by 'prepare0'. None of 'gdb_script' depends on 'prepare'.

Loosen the dependency.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
      7a739ce5
    • M
      kbuild: remove stale dependency between Documentation/ and headers_install · 3a51f908
      由 Masahiro Yamada 提交于 
      Commit 8e2faea8 ("Make Documenation depend on headers_install")
dates back to 2014, which is before Sphinx was introduced for the
kernel documentation.

Since none of DOC_TARGET requires headers_install, it is strange to
run it only for the single target "Documentation/".
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
      3a51f908
    • M
      kbuild: remove headers_{install,check}_all · f3c8d4c7
      由 Masahiro Yamada 提交于 
      headers_install_all does not make much sense any more because different
architectures export different set of uapi/linux/ headers. As you see
in include/uapi/linux/Kbuild, the installation of a.out.h, kvm.h, and
kvm_para.h is arch-dependent. So, headers_install_all repeats the
installation/removal of them.

If somebody really thinks it is useful to do headers_install for all
architectures, it would be possible by small shell-scripting, but
the top Makefile does not have to provide entry targets just for that
purpose.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: NSam Ravnborg <sam@ravnborg.org>
      f3c8d4c7
  13. 09 6月, 2019 1 次提交
    • M
      kbuild: Remove -Waggregate-return from scripts/Makefile.extrawarn · 869ee58b
      由 Mathieu Malaterre 提交于 
      It makes little sense to pass -Waggregate-return these days since large
part of the linux kernel rely on returning struct(s). For instance:

  ../include/linux/timekeeping.h: In function 'show_uptime':
  ../include/linux/ktime.h:91:34: error: function call has aggregate value [-Werror=aggregate-return]
   #define ktime_to_timespec64(kt)  ns_to_timespec64((kt))
                                    ^~~~~~~~~~~~~~~~~~~~~~
  ../include/linux/timekeeping.h:166:8: note: in expansion of macro 'ktime_to_timespec64'
    *ts = ktime_to_timespec64(ktime_get_coarse_boottime());

Remove this warning from W=2 completely.
Signed-off-by: NMathieu Malaterre <malat@debian.org>
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
      869ee58b