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  1. 14 10月, 2020 1 次提交
  3. 03 9月, 2020 1 次提交
  5. 10 8月, 2020 2 次提交
    • M
      kbuild: introduce hostprogs-always-y and userprogs-always-y · faabed29
      由 Masahiro Yamada 提交于 
      To build host programs, you need to add the program names to 'hostprogs'
to use the necessary build rule, but it is not enough to build them
because there is no dependency.

There are two types of host programs: built as the prerequisite of
another (e.g. gen_crc32table in lib/Makefile), or always built when
Kbuild visits the Makefile (e.g. genksyms in scripts/genksyms/Makefile).

The latter is typical in Makefiles under scripts/, which contains host
programs globally used during the kernel build. To build them, you need
to add them to both 'hostprogs' and 'always-y'.

This commit adds hostprogs-always-y as a shorthand.

The same applies to user programs. net/bpfilter/Makefile builds
bpfilter_umh on demand, hence always-y is unneeded. In contrast,
programs under samples/ are added to both 'userprogs' and 'always-y'
so they are always built when Kbuild visits the Makefiles.

userprogs-always-y works as a shorthand.
Signed-off-by: NMasahiro Yamada <masahiroy@kernel.org>
Acked-by: NMiguel Ojeda <miguel.ojeda.sandonis@gmail.com>
      faabed29
    • M
      kbuild: introduce ccflags-remove-y and asflags-remove-y · 15d5761a
      由 Masahiro Yamada 提交于 
      CFLAGS_REMOVE_<file>.o filters out flags when compiling a particular
object, but there is no convenient way to do that for every object in
a directory.

Add ccflags-remove-y and asflags-remove-y to make it easily.

Use ccflags-remove-y to clean up some Makefiles.

The add/remove order works as follows:

 [1] KBUILD_CFLAGS specifies compiler flags used globally

 [2] ccflags-y adds compiler flags for all objects in the
     current Makefile

 [3] ccflags-remove-y removes compiler flags for all objects in the
     current Makefile (New feature)

 [4] CFLAGS_<file> adds compiler flags per file.

 [5] CFLAGS_REMOVE_<file> removes compiler flags per file.

Having [3] before [4] allows us to remove flags from most (but not all)
objects in the current Makefile.

For example, kernel/trace/Makefile removes $(CC_FLAGS_FTRACE)
from all objects in the directory, then adds it back to
trace_selftest_dynamic.o and CFLAGS_trace_kprobe_selftest.o

The same applies to lib/livepatch/Makefile.

Please note ccflags-remove-y has no effect to the sub-directories.
In contrast, the previous notation got rid of compiler flags also from
all the sub-directories.

The following are not affected because they have no sub-directories:

  arch/arm/boot/compressed/
  arch/powerpc/xmon/
  arch/sh/
  kernel/trace/

However, lib/ has several sub-directories.

To keep the behavior, I added ccflags-remove-y to all Makefiles
in subdirectories of lib/, except the following:

  lib/vdso/Makefile        - Kbuild does not descend into this Makefile
  lib/raid/test/Makefile   - This is not used for the kernel build

I think commit 2464a609 ("ftrace: do not trace library functions")
excluded too much. In the next commit, I will remove ccflags-remove-y
from the sub-directories of lib/.
Suggested-by: NSami Tolvanen <samitolvanen@google.com>
Signed-off-by: NMasahiro Yamada <masahiroy@kernel.org>
Acked-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Acked-by: Brendan Higgins <brendanhiggins@google.com> (KUnit)
Tested-by: NAnders Roxell <anders.roxell@linaro.org>
      15d5761a
  7. 06 6月, 2020 1 次提交
  9. 17 5月, 2020 1 次提交
  11. 23 4月, 2020 1 次提交
  13. 13 3月, 2020 1 次提交
  15. 27 2月, 2020 2 次提交
  17. 04 2月, 2020 2 次提交
    • M
      kbuild: rename hostprogs-y/always to hostprogs/always-y · 5f2fb52f
      由 Masahiro Yamada 提交于 
      In old days, the "host-progs" syntax was used for specifying host
programs. It was renamed to the current "hostprogs-y" in 2004.

It is typically useful in scripts/Makefile because it allows Kbuild to
selectively compile host programs based on the kernel configuration.

This commit renames like follows:

  always       ->  always-y
  hostprogs-y  ->  hostprogs

So, scripts/Makefile will look like this:

  always-$(CONFIG_BUILD_BIN2C) += ...
  always-$(CONFIG_KALLSYMS)    += ...
      ...
  hostprogs := $(always-y) $(always-m)

I think this makes more sense because a host program is always a host
program, irrespective of the kernel configuration. We want to specify
which ones to compile by CONFIG options, so always-y will be handier.

The "always", "hostprogs-y", "hostprogs-m" will be kept for backward
compatibility for a while.
Signed-off-by: NMasahiro Yamada <masahiroy@kernel.org>
      5f2fb52f
    • M
      kbuild: fix the document to use extra-y for vmlinux.lds · faa7bdd7
      由 Masahiro Yamada 提交于 
      The difference between "always" and "extra-y" is that the targets
listed in $(always) are always built, whereas the ones in $(extra-y)
are built only when KBUILD_BUILTIN is set.

So, "make modules" does not build the targets in $(extra-y).

vmlinux.lds is only needed for linking vmlinux. So, adding it to extra-y
is more correct. In fact, arch/x86/kernel/Makefile does this.

Fix the example code.
Signed-off-by: NMasahiro Yamada <masahiroy@kernel.org>
      faa7bdd7
  19. 21 12月, 2019 1 次提交
    • M
      kbuild: clarify the difference between obj-y and obj-m w.r.t. descending · 28f94a44
      由 Masahiro Yamada 提交于 
      Kbuild descends into a directory by either 'y' or 'm', but there is an
important difference.

Kbuild combines the built-in objects into built-in.a in each directory.
The built-in.a in the directory visited by obj-y is merged into the
built-in.a in the parent directory. This merge happens recursively
when Kbuild is ascending back towards the top directory, then built-in
objects are linked into vmlinux eventually. This works properly only
when the Makefile specifying obj-y is reachable by the chain of obj-y.

On the other hand, Kbuild does not take built-in.a from the directory
visited by obj-m. This it, all the objects in that directory are
supposed to be modular. If Kbuild descends into a directory by obj-m,
but the Makefile in the sub-directory specifies obj-y, those objects
are just left orphan.

The current statement "Kbuild only uses this information to decide that
it needs to visit the directory" is misleading. Clarify the difference.
Reported-by: NJohan Hovold <johan@kernel.org>
Signed-off-by: NMasahiro Yamada <masahiroy@kernel.org>
Reviewed-by: NJohan Hovold <johan@kernel.org>
      28f94a44
  21. 14 11月, 2019 1 次提交
    • M
      kbuild: remove header compile test · fcbb8461
      由 Masahiro Yamada 提交于 
      There are both positive and negative options about this feature.
At first, I thought it was a good idea, but actually Linus stated a
negative opinion (https://lkml.org/lkml/2019/9/29/227). I admit it
is ugly and annoying.

The baseline I'd like to keep is the compile-test of uapi headers.
(Otherwise, kernel developers have no way to ensure the correctness
of the exported headers.)

I will maintain a small build rule in usr/include/Makefile.
Remove the other header test functionality.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
      fcbb8461
  23. 01 10月, 2019 1 次提交
  25. 04 9月, 2019 1 次提交
  27. 29 8月, 2019 3 次提交
    • M
      kbuild: remove clean-dirs syntax · 1634f2bf
      由 Masahiro Yamada 提交于 
      The only the difference between clean-files and clean-dirs is the -r
option passed to the 'rm' command.

You can always pass -r, and then remove the clean-dirs syntax.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
      1634f2bf
    • M
      docs: kbuild: remove cc-ldoption from document again · d20558d1
      由 Masahiro Yamada 提交于 
      Commit 055efab3 ("kbuild: drop support for cc-ldoption") correctly
removed the cc-ldoption from Documentation/kbuild/makefiles.txt, but
commit cd238eff ("docs: kbuild: convert docs to ReST and rename
to *.rst") revived it. I guess it was a rebase mistake.

Remove it again.

Fixes: cd238eff ("docs: kbuild: convert docs to ReST and rename to *.rst")
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
      d20558d1
    • M
      docs: kbuild: fix invalid ReST syntax · 4fef9dec
      由 Masahiro Yamada 提交于 
      I see the following warnings when I open this document with a ReST
viewer, retext:

/home/masahiro/ref/linux/Documentation/kbuild/makefiles.rst:1142: (WARNING/2) Inline emphasis start-string without end-string.
/home/masahiro/ref/linux/Documentation/kbuild/makefiles.rst:1152: (WARNING/2) Inline emphasis start-string without end-string.
/home/masahiro/ref/linux/Documentation/kbuild/makefiles.rst:1154: (WARNING/2) Inline emphasis start-string without end-string.

These hunks were added by commit e846f0dc ("kbuild: add support
for ensuring headers are self-contained") and commit 1e21cbfa
("kbuild: support header-test-pattern-y"), respectively. They were
written not for ReST but for the plain text, and merged via the
kbuild tree.

In the same development cycle, this document was converted to ReST
by commit cd238eff ("docs: kbuild: convert docs to ReST and rename
to *.rst"), and merged via the doc sub-system.

Merging them together into Linus' tree resulted in the current situation.

To fix the syntax, surround the asterisks with back-quotes, and
use :: for the code sample.

Fixes: 39ceda5c ("Merge tag 'kbuild-v5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild")
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
      4fef9dec
  29. 21 8月, 2019 3 次提交
  31. 17 7月, 2019 1 次提交
  33. 15 7月, 2019 1 次提交
  35. 15 6月, 2019 1 次提交
    • M
      docs: kbuild: convert docs to ReST and rename to *.rst · cd238eff
      由 Mauro Carvalho Chehab 提交于 
      The kbuild documentation clearly shows that the documents
there are written at different times: some use markdown,
some use their own peculiar logic to split sections.

Convert everything to ReST without affecting too much
the author's style and avoiding adding uneeded markups.

The conversion is actually:
  - add blank lines and identation in order to identify paragraphs;
  - fix tables markups;
  - add some lists markups;
  - mark literal blocks;
  - adjust title markups.

At its new index.rst, let's add a :orphan: while this is not linked to
the main index.rst file, in order to avoid build warnings.
Signed-off-by: NMauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: NJonathan Corbet <corbet@lwn.net>
      cd238eff
  37. 20 5月, 2019 1 次提交
  39. 17 3月, 2019 1 次提交
  41. 04 3月, 2019 1 次提交
    • M
      kbuild: remove cc-version macro · d3a918c6
      由 Masahiro Yamada 提交于 
      There is no more direct user of this macro; it is only used by
cc-ifversion.

Calling this macro is not efficient since it invokes the compiler to
get the compiler version. CONFIG_GCC_VERSION is already calculated in
the Kconfig stage, so Makefile can reuse it.

Here is a note about the slight difference between cc-version and
CONFIG_GCC_VERSION:

When using Clang, cc-version is evaluated to '0402' because Clang
defines __GNUC__ and __GNUC__MINOR__, and looks like GCC 4.2 in the
version point of view. On the other hand, CONFIG_GCC_VERSION=0
when $(CC) is clang.

There are currently two users of cc-ifversion:
  arch/mips/loongson64/Platform
  arch/powerpc/Makefile

They are not affected by this change.

The format of cc-version is <major><minor>, while CONFIG_GCC_VERSION
<major><minor><patch>. I adjusted cc-ifversion for the difference of
the number of digits.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
      d3a918c6
  43. 28 1月, 2019 1 次提交
  45. 06 1月, 2019 1 次提交
  47. 01 11月, 2018 1 次提交
  49. 22 8月, 2018 1 次提交
  51. 21 7月, 2018 1 次提交
    • D
      kbuild: if_changed: document single use per target limitation · bb81955f
      由 Dirk Gouders 提交于 
      Users of if_changed could easily feel invited to use it to divide a
recipe into parts like:

a: prereq FORCE
	$(call if_changed,do_a)
	$(call if_changed,do_b)

But this is problematic, because if_changed should not be used more
than once per target: in the above example, if_changed stores the
command-line of the given command in .a.cmd and when a is up-to-date
with respect to prereq, the file .a.cmd contains the command-line for
the last command executed, i.e. do_b.

When the recipe is then executed again, without any change of
prerequisites, the command-line check for do_a will fail, do_a will be
executed and stored in .a.cmd.  The next check, however, will still see
the old content (the file isn't re-read) and if_changed will skip
do_b, because the command-line test will not recognize a change.  On
the next execution of the recipe the roles will flip: do_a is OK but
do_b not and it will be executed.  And so on...
Signed-off-by: NDirk Gouders <dirk@gouders.net>
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
      bb81955f
  53. 18 7月, 2018 1 次提交
  55. 26 3月, 2018 3 次提交
    • M
      kbuild: remove command line interface LDFLAGS_MODULE from makefiles.txt · 35cd02be
      由 Masahiro Yamada 提交于 
      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: NMasahiro Yamada <yamada.masahiro@socionext.com>
      35cd02be
    • N
      kbuild: rename built-in.o to built-in.a · f49821ee
      由 Nicholas Piggin 提交于 
      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: NNicholas Piggin <npiggin@gmail.com>
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
      f49821ee
    • N
      kbuild: remove incremental linking option · 6358d6e8
      由 Nicholas Piggin 提交于 
      This removes the old `ld -r` incremental link option, which has not
been selected by any architecture since June 2017.
Signed-off-by: NNicholas Piggin <npiggin@gmail.com>
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
      6358d6e8
  57. 09 11月, 2017 1 次提交
  59. 24 10月, 2017 1 次提交
  61. 08 8月, 2017 1 次提交