Commit Graph

1652 Commits

Author SHA1 Message Date
Linus Torvalds 609488bc97 Linux 5.3-rc2 2019-07-28 12:47:02 -07:00
Gustavo A. R. Silva a035d552a9 Makefile: Globally enable fall-through warning
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>
2019-07-25 20:13:54 -05:00
Linus Torvalds 5f9e832c13 Linus 5.3-rc1 2019-07-21 14:05:38 -07:00
Seth Forshee 29be86d7f9 kbuild: add -fcf-protection=none when using retpoline flags
The gcc -fcf-protection=branch option is not compatible with
-mindirect-branch=thunk-extern. The latter is used when
CONFIG_RETPOLINE is selected, and this will fail to build with
a gcc which has -fcf-protection=branch enabled by default. Adding
-fcf-protection=none when building with retpoline enabled
prevents such build failures.

Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-07-20 11:20:24 +09:00
Masahiro Yamada 30527cefb3 kbuild: remove 'prepare1' target
Now that there is no rule for 'prepare1', it can go away.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-07-18 02:19:31 +09:00
Masahiro Yamada b7dca6dd1e kbuild: create *.mod with full directory path and remove MODVERDIR
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>
2019-07-18 02:19:31 +09:00
Masahiro Yamada ff9b45c55b kbuild: modpost: read modules.order instead of $(MODVERDIR)/*.mod
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>
2019-07-18 02:16:27 +09:00
Masahiro Yamada 1bd9a46801 kbuild: get rid of kernel/ prefix from in-tree modules.{order,builtin}
Removing the 'kernel/' prefix will make our life easier because we can
simply do 'cat modules.order' to get all built modules with full paths.

Currently, we parse the first line of '*.mod' files in $(MODVERDIR).
Since we have duplicated functionality here, I plan to remove MODVERDIR
entirely.

In fact, modules.order is generated also for external modules in a
broken format. It adds the 'kernel/' prefix to the absolute path of
the module, like this:

  kernel//path/to/your/external/module/foo.ko

This is fine for now since modules.order is not used for external
modules. However, I want to sanitize the format everywhere towards
the goal of removing MODVERDIR.

We cannot change the format of installed module.{order,builtin}.
So, 'make modules_install' will add the 'kernel/' prefix while copying
them to $(MODLIB)/.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-07-17 22:39:27 +09:00
Masahiro Yamada 7e13191879 kbuild: do not create empty modules.order in the prepare stage
Currently, $(objtree)/modules.order is touched in two places.

In the 'prepare0' rule, scripts/Makefile.build creates an empty
modules.order while processing 'obj=.'

In the 'modules' rule, the top-level Makefile overwrites it with
the correct list of modules.

While this might be a good side-effect that modules.order is made
empty every time (probably this is not intended functionality),
I personally do not like this behavior.

Create modules.order only when it is sensible to do so.

This avoids creating the following pointless files:

  scripts/basic/modules.order
  scripts/dtc/modules.order
  scripts/gcc-plugins/modules.order
  scripts/genksyms/modules.order
  scripts/mod/modules.order
  scripts/modules.order
  scripts/selinux/genheaders/modules.order
  scripts/selinux/mdp/modules.order
  scripts/selinux/modules.order

Going forward, $(objtree)/modules.order lists the modules that
was built in the last successful build.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-07-17 22:39:27 +09:00
Masahiro Yamada 46457133ac kbuild: remove tag files by distclean instead of mrproper
It takes somewhat long time to generate these tag files.
Keep such precious files until we run 'make distclean'.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-07-17 22:37:51 +09:00
Masahiro Yamada 89ff7131f7 kbuild: add --hash-style= and --build-id unconditionally
As commit 1e0221374e ("mips: vdso: drop unnecessary cc-ldoption")
explained, these flags are supported by the minimal required version
of binutils. They are supported by ld.lld too.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Tested-by: Nathan Chancellor <natechancellor@gmail.com>
2019-07-17 22:37:51 +09:00
Linus Torvalds 39ceda5ce1 Kbuild updates for v5.3
- remove headers_{install,check}_all targets
 
 - remove unreasonable 'depends on !UML' from CONFIG_SAMPLES
 
 - re-implement 'make headers_install' more cleanly
 
 - add new header-test-y syntax to compile-test headers
 
 - compile-test exported headers to ensure they are compilable in
   user-space
 
 - compile-test headers under include/ to ensure they are self-contained
 
 - remove -Waggregate-return, -Wno-uninitialized, -Wno-unused-value flags
 
 - add -Werror=unknown-warning-option for Clang
 
 - add 128-bit built-in types support to genksyms
 
 - fix missed rebuild of modules.builtin
 
 - propagate 'No space left on device' error in fixdep to Make
 
 - allow Clang to use its integrated assembler
 
 - improve some coccinelle scripts
 
 - add a new flag KBUILD_ABS_SRCTREE to request Kbuild to use absolute
   path for $(srctree).
 
 - do not ignore errors when compression utility is missing
 
 - misc cleanups
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Merge tag 'kbuild-v5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild updates from Masahiro Yamada:

 - remove headers_{install,check}_all targets

 - remove unreasonable 'depends on !UML' from CONFIG_SAMPLES

 - re-implement 'make headers_install' more cleanly

 - add new header-test-y syntax to compile-test headers

 - compile-test exported headers to ensure they are compilable in
   user-space

 - compile-test headers under include/ to ensure they are self-contained

 - remove -Waggregate-return, -Wno-uninitialized, -Wno-unused-value
   flags

 - add -Werror=unknown-warning-option for Clang

 - add 128-bit built-in types support to genksyms

 - fix missed rebuild of modules.builtin

 - propagate 'No space left on device' error in fixdep to Make

 - allow Clang to use its integrated assembler

 - improve some coccinelle scripts

 - add a new flag KBUILD_ABS_SRCTREE to request Kbuild to use absolute
   path for $(srctree).

 - do not ignore errors when compression utility is missing

 - misc cleanups

* tag 'kbuild-v5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (49 commits)
  kbuild: use -- separater intead of $(filter-out ...) for cc-cross-prefix
  kbuild: Inform user to pass ARCH= for make mrproper
  kbuild: fix compression errors getting ignored
  kbuild: add a flag to force absolute path for srctree
  kbuild: replace KBUILD_SRCTREE with boolean building_out_of_srctree
  kbuild: remove src and obj from the top Makefile
  scripts/tags.sh: remove unused environment variables from comments
  scripts/tags.sh: drop SUBARCH support for ARM
  kbuild: compile-test kernel headers to ensure they are self-contained
  kheaders: include only headers into kheaders_data.tar.xz
  kheaders: remove meaningless -R option of 'ls'
  kbuild: support header-test-pattern-y
  kbuild: do not create wrappers for header-test-y
  kbuild: compile-test exported headers to ensure they are self-contained
  init/Kconfig: add CONFIG_CC_CAN_LINK
  kallsyms: exclude kasan local symbols on s390
  kbuild: add more hints about SUBDIRS replacement
  coccinelle: api/stream_open: treat all wait_.*() calls as blocking
  coccinelle: put_device: Add a cast to an expression for an assignment
  coccinelle: put_device: Adjust a message construction
  ...
2019-07-12 16:03:16 -07:00
Geert Uytterhoeven 3a475b2166 kbuild: Inform user to pass ARCH= for make mrproper
When cross-compiling an out-of-tree build with an unclean source tree
directory, the build fails with:

  /path/to/kernel/source/tree is not clean, please run 'make mrproper'
  in the '/path/to/kernel/source/tree' directory.

However, doing so does not fix the problem, as "make mrproper" now
requires passing the target architecture to the make command, else it
won't remove $(srctree)/arch/$(SRCARCH)/include/generated.
"git ls-files -o" doesn't give a clue, as it doesn't list (empty)
directories, only files.

Improve usability by including the ARCH= option in the error output.

Fixes: a788b2ed81 ("kbuild: check arch/$(SRCARCH)/include/generated before out-of-tree build")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-07-11 00:05:09 +09:00
Masahiro Yamada 95fd3f87bf kbuild: add a flag to force absolute path for srctree
In old days, Kbuild always used an absolute path for $(srctree).

Since commit 890676c65d ("kbuild: Use relative path when building in
the source tree"), $(srctree) is '.' when O= was not passed from the
command line.

Yet, using absolute paths is useful in some cases even without O=, for
instance, to create a cscope file with absolute path tags.

'O=.' was known to work as a workaround to force Kbuild to use absolute
paths even when you are building in the source tree.

Since commit 25b146c5b8 ("kbuild: allow Kbuild to start from any
directory"), Kbuild is too clever to be tricked. Even if you pass 'O=.'
Kbuild notices you are building in the source tree, then use '.' for
$(srctree).

So, 'make O=. cscope' is no help to create absolute path tags.

We cannot force one or the other according to commit e93bc1a0ca
("Revert "kbuild: specify absolute paths for cscope""). Both of
relative path and absolute path have pros and cons.

This commit adds a new flag KBUILD_ABS_SRCTREE to allow users to
choose the absolute path for $(srctree).

'make KBUILD_ABS_SRCTREE=1 cscope' will work as a replacement of
'make O=. cscope'.

Reported-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-07-11 00:05:09 +09:00
Masahiro Yamada 051f278e9d kbuild: replace KBUILD_SRCTREE with boolean building_out_of_srctree
Commit 25b146c5b8 ("kbuild: allow Kbuild to start from any directory")
deprecated KBUILD_SRCTREE.

It is only used in tools/testing/selftest/ to distinguish out-of-tree
build. Replace it with a new boolean flag, building_out_of_srctree.

I also replaced the conditional ($(srctree),.) because the next commit
will allow an absolute path to be used for $(srctree) even when building
in the source tree.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-07-11 00:05:09 +09:00
Masahiro Yamada 75dd47472b kbuild: remove src and obj from the top Makefile
Replace $(src) and $(obj) with $(srctree) and $(objtree), respectively.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-07-11 00:05:09 +09:00
Masahiro Yamada 43c78d8803 kbuild: compile-test kernel headers to ensure they are self-contained
The headers in include/ are globally used in the kernel source tree
to provide common APIs. They are included from external modules, too.

It will be useful to make as many headers self-contained as possible
so that we do not have to rely on a specific include order.

There are more than 4000 headers in include/. In my rough analysis,
70% of them are already self-contained. With efforts, most of them
can be self-contained.

For now, we must exclude more than 1000 headers just because they
cannot be compiled as standalone units. I added them to header-test-.
The blacklist was mostly generated by a script, so the reason of the
breakage should be checked later.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Tested-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
2019-07-09 21:44:37 +09:00
Masahiro Yamada c93a0368aa kbuild: do not create wrappers for header-test-y
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 abb2ea7dfd ("compiler,
clang: suppress warning for unused static inline functions"), but we
should not rely on that.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Tested-by: Jani Nikula <jani.nikula@intel.com>
2019-07-09 10:10:27 +09:00
Masahiro Yamada d6fc9fcbaa kbuild: compile-test exported headers to ensure they are self-contained
Multiple people have suggested compile-testing UAPI headers to ensure
they can be really included from user-space. "make headers_check" is
obviously not enough to catch bugs, and we often leak unresolved
references to user-space.

Use the new header-test-y syntax to implement it. Please note exported
headers are compile-tested with a completely different set of compiler
flags. The header search path is set to $(objtree)/usr/include since
exported headers should not include unexported ones.

We use -std=gnu89 for the kernel space since the kernel code highly
depends on GNU extensions. On the other hand, UAPI headers should be
written in more standardized C, so they are compiled with -std=c90.
This will emit errors if C++ style comments, the keyword 'inline', etc.
are used. Please use C style comments (/* ... */), '__inline__', etc.
in UAPI headers.

There is additional compiler requirement to enable this test because
many of UAPI headers include <stdlib.h>, <sys/ioctl.h>, <sys/time.h>,
etc. directly or indirectly. You cannot use kernel.org pre-built
toolchains [1] since they lack <stdlib.h>.

I reused CONFIG_CC_CAN_LINK to check the system header availability.
The intention is slightly different, but a compiler that can link
userspace programs provide system headers.

For now, a lot of headers need to be excluded because they cannot
be compiled standalone, but this is a good start point.

[1] https://mirrors.edge.kernel.org/pub/tools/crosstool/index.html

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
2019-07-08 23:13:57 +09:00
Linus Torvalds 0ecfebd2b5 Linux 5.2 2019-07-07 15:41:56 -07:00
Masahiro Yamada 4e8fc3f55a kbuild: add more hints about SUBDIRS replacement
Commit 0126be38d9 ("kbuild: announce removal of SUBDIRS if used")
added a hint about the 'SUBDIRS' replacement, but it was not clear
enough.

Multiple people sent me similar questions, patches. For instance,

  https://lkml.org/lkml/2019/1/17/456

I did not mean to use M= for building a subdirectory in the kernel tree.

From commit 669efc76b3 ("net: hns3: fix compile error"), people
already (ab)use M=... to do that because it seems to work to some extent.

Documentation/kbuild/kbuild.txt says M= and KBUILD_EXTMOD are used for
building external modules.

In fact, Kbuild supports the single target '%/' for this purpose, but
this may not be noticed much.

Kindly add more hints.

Makefile:213: ================= WARNING ================
Makefile:214: 'SUBDIRS' will be removed after Linux 5.3
Makefile:215:
Makefile:216: If you are building an individual subdirectory
Makefile:217: in the kernel tree, you can do like this:
Makefile:218: $ make path/to/dir/you/want/to/build/
Makefile:219: (Do not forget the trailing slash)
Makefile:220:
Makefile:221: If you are building an external module,
Makefile:222: Please use 'M=' or 'KBUILD_EXTMOD' instead
Makefile:223: ==========================================

Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
2019-07-08 02:25:59 +09:00
Nathan Chancellor 876a060089 kbuild: Add ability to test Clang's integrated assembler
There are some people interested in experimenting with Clang's
integrated assembler. To make it easy to do so without source
modification, allow the user to specify 'AS=clang' as part of the
make command to avoid adding '-no-integrated-as' to the {A,C}FLAGS.

Link: https://github.com/ClangBuiltLinux/linux/issues/577
Suggested-by: Dmitry Golovin <dima@golovin.in>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-07-04 08:28:29 +09:00
Masahiro Yamada 68980b4704 kbuild: split modules.order build rule out of 'modules' target
modules.order is a real target. Split its build rule out like
modules.builtin

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-07-01 10:09:28 +09:00
Masahiro Yamada 50ef0cdf58 kbuild: fix missed rebuild of modules.builtin
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: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-07-01 10:04:46 +09:00
Linus Torvalds 6fbc7275c7 Linux 5.2-rc7 2019-06-30 11:25:36 +08:00
Nathan Chancellor 589834b3a0 kbuild: Add -Werror=unknown-warning-option to CLANG_FLAGS
In commit ebcc5928c5 ("arm64: Silence gcc warnings about arch ABI
drift"), the arm64 Makefile added -Wno-psabi to KBUILD_CFLAGS, which is
a GCC only option so clang rightfully complains:

warning: unknown warning option '-Wno-psabi' [-Wunknown-warning-option]

https://clang.llvm.org/docs/DiagnosticsReference.html#wunknown-warning-option

However, by default, this is merely a warning so the build happily goes
on with a slew of these warnings in the process.

Commit c3f0d0bc5b ("kbuild, LLVMLinux: Add -Werror to cc-option to
support clang") worked around this behavior in cc-option by adding
-Werror so that unknown flags cause an error. However, this all happens
silently and when an unknown flag is added to the build unconditionally
like -Wno-psabi, cc-option will always fail because there is always an
unknown flag in the list of flags. This manifested as link time failures
in the arm64 libstub because -fno-stack-protector didn't get added to
KBUILD_CFLAGS.

To avoid these weird cryptic failures in the future, make clang behave
like gcc and immediately error when it encounters an unknown flag by
adding -Werror=unknown-warning-option to CLANG_FLAGS. This can be added
unconditionally for clang because it is supported by at least 3.0.0,
according to godbolt [1] and 4.0.0, according to its documentation [2],
which is far earlier than we typically support.

[1]: https://godbolt.org/z/7F7rm3
[2]: https://releases.llvm.org/4.0.0/tools/clang/docs/DiagnosticsReference.html#wunknown-warning-option

Link: https://github.com/ClangBuiltLinux/linux/issues/511
Link: https://github.com/ClangBuiltLinux/linux/issues/517
Suggested-by: Peter Smith <peter.smith@linaro.org>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-06-24 03:43:03 +09:00
Linus Torvalds 4b972a01a7 Linux 5.2-rc6 2019-06-22 16:01:36 -07:00
Linus Torvalds 9e0babf2c0 Linux 5.2-rc5 2019-06-16 08:49:45 -10:00
Jani Nikula e846f0dc57 kbuild: add support for ensuring headers are self-contained
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: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-06-15 19:57:02 +09:00
Masahiro Yamada a5bae54c10 kbuild: move hdr-inst shorthand to top Makefile
Now that hdr-inst is used only in the top Makefile, move it there
from scripts/Kbuild.include.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-06-15 19:57:02 +09:00
Masahiro Yamada d5470d1443 kbuild: re-implement Makefile.headersinst without recursion
Since commit fcc8487d47 ("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: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-06-15 19:57:02 +09:00
Masahiro Yamada 59b2bd05f5 kbuild: add 'headers' target to build up uapi headers in usr/include
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: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-06-15 19:57:02 +09:00
Masahiro Yamada bdd7714b6f kbuild: build all prerequisites of headers_install simultaneously
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: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-06-15 19:57:02 +09:00
Masahiro Yamada 2b8481be3c kbuild: remove build_unifdef target in scripts/Makefile
Since commit 2aedcd098a ("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: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-06-15 19:57:01 +09:00
Masahiro Yamada e949f4c2d6 kbuild: add CONFIG_HEADERS_INSTALL and loosen the dependency of samples
Commit 5318321d36 ("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: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-06-15 19:57:01 +09:00
Masahiro Yamada 7a739ce51d kbuild: make gdb_script depend on prepare0 instead of prepare
'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: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-06-15 19:57:01 +09:00
Masahiro Yamada 3a51f9081e kbuild: remove stale dependency between Documentation/ and headers_install
Commit 8e2faea877 ("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: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-06-15 19:57:01 +09:00
Masahiro Yamada f3c8d4c7a7 kbuild: remove headers_{install,check}_all
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: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
2019-06-15 19:57:01 +09:00
Linus Torvalds d1fdb6d8f6 Linux 5.2-rc4 2019-06-08 20:24:46 -07:00
Dan Rue 6d3db46c8e kbuild: teach kselftest-merge to find nested config files
Current implementation of kselftest-merge only finds config files that
are one level deep using `$(srctree)/tools/testing/selftests/*/config`.

Often, config files are added in nested directories, and do not get
picked up by kselftest-merge.

Use `find` to catch all config files under
`$(srctree)/tools/testing/selftests` instead.

Signed-off-by: Dan Rue <dan.rue@linaro.org>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-06-05 02:33:10 +09:00
Linus Torvalds f2c7c76c5d Linux 5.2-rc3 2019-06-02 13:55:33 -07:00
Linus Torvalds cd6c84d8f0 Linux 5.2-rc2 2019-05-26 16:49:19 -07:00
Linus Torvalds a188339ca5 Linux 5.2-rc1 2019-05-19 15:47:09 -07:00
Masahiro Yamada 3a48a91901 kbuild: check uniqueness of module names
In the recent build test of linux-next, Stephen saw a build error
caused by a broken .tmp_versions/*.mod file:

  https://lkml.org/lkml/2019/5/13/991

drivers/net/phy/asix.ko and drivers/net/usb/asix.ko have the same
basename, and there is a race in generating .tmp_versions/asix.mod

Kbuild has not checked this before, and it suddenly shows up with
obscure error messages when this kind of race occurs.

Non-unique module names cause various sort of problems, but it is
not trivial to catch them by eyes.

Hence, this script.

It checks not only real modules, but also built-in modules (i.e.
controlled by tristate CONFIG option, but currently compiled with =y).
Non-unique names for built-in modules also cause problems because
/sys/modules/ would fall over.

For the latest kernel, I tested "make allmodconfig all" (or more
quickly "make allyesconfig modules"), and it detected the following:

warning: same basename if the following are built as modules:
  drivers/regulator/88pm800.ko
  drivers/mfd/88pm800.ko
warning: same basename if the following are built as modules:
  drivers/gpu/drm/bridge/adv7511/adv7511.ko
  drivers/media/i2c/adv7511.ko
warning: same basename if the following are built as modules:
  drivers/net/phy/asix.ko
  drivers/net/usb/asix.ko
warning: same basename if the following are built as modules:
  fs/coda/coda.ko
  drivers/media/platform/coda/coda.ko
warning: same basename if the following are built as modules:
  drivers/net/phy/realtek.ko
  drivers/net/dsa/realtek.ko

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
2019-05-18 15:35:02 +09:00
Masahiro Yamada 233c741dcb kbuild: add LICENSES to KBUILD_ALLDIRS
For *-pkg targets, the LICENSES directory should be included in the
source tarball.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-05-18 11:49:57 +09:00
Masahiro Yamada 902a6898bf kbuild: terminate Kconfig when $(CC) or $(LD) is missing
If the compiler specified by $(CC) is not present, the Kconfig stage
sprinkles 'not found' messages, then succeeds.

  $ make CROSS_COMPILE=foo defconfig
  /bin/sh: 1: foogcc: not found
  /bin/sh: 1: foogcc: not found
  *** Default configuration is based on 'x86_64_defconfig'
  ./scripts/gcc-version.sh: 17: ./scripts/gcc-version.sh: foogcc: not found
  ./scripts/gcc-version.sh: 18: ./scripts/gcc-version.sh: foogcc: not found
  ./scripts/gcc-version.sh: 19: ./scripts/gcc-version.sh: foogcc: not found
  ./scripts/gcc-version.sh: 17: ./scripts/gcc-version.sh: foogcc: not found
  ./scripts/gcc-version.sh: 18: ./scripts/gcc-version.sh: foogcc: not found
  ./scripts/gcc-version.sh: 19: ./scripts/gcc-version.sh: foogcc: not found
  ./scripts/clang-version.sh: 11: ./scripts/clang-version.sh: foogcc: not found
  ./scripts/gcc-plugin.sh: 11: ./scripts/gcc-plugin.sh: foogcc: not found
  init/Kconfig:16:warning: 'GCC_VERSION': number is invalid
  #
  # configuration written to .config
  #

Terminate parsing files immediately if $(CC) or $(LD) is not found.
"make *config" will fail more nicely.

  $ make CROSS_COMPILE=foo defconfig
  *** Default configuration is based on 'x86_64_defconfig'
  scripts/Kconfig.include:34: compiler 'foogcc' not found
  make[1]: *** [scripts/kconfig/Makefile;82: defconfig] Error 1
  make: *** [Makefile;557: defconfig] Error 2

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-05-18 11:49:55 +09:00
Masahiro Yamada d2f8ae0e4c kbuild: turn auto.conf.cmd into a mandatory include file
syncconfig is responsible for keeping auto.conf up-to-date, so if it
fails for any reason, the build must be terminated immediately.

However, since commit 9390dff66a ("kbuild: invoke syncconfig if
include/config/auto.conf.cmd is missing"), Kbuild continues running
even after syncconfig fails.

You can confirm this by intentionally making syncconfig error out:

  diff --git a/scripts/kconfig/confdata.c b/scripts/kconfig/confdata.c
  index 08ba146..307b9de 100644
  --- a/scripts/kconfig/confdata.c
  +++ b/scripts/kconfig/confdata.c
  @@ -1023,6 +1023,9 @@ int conf_write_autoconf(int overwrite)
          FILE *out, *tristate, *out_h;
          int i;

  +       if (overwrite)
  +               return 1;
  +
          if (!overwrite && is_present(autoconf_name))
                  return 0;

Then, syncconfig fails, but Make would not stop:

  $ make -s mrproper allyesconfig defconfig
  $ make
  scripts/kconfig/conf  --syncconfig Kconfig

  *** Error during sync of the configuration.

  make[2]: *** [scripts/kconfig/Makefile;69: syncconfig] Error 1
  make[1]: *** [Makefile;557: syncconfig] Error 2
  make: *** [include/config/auto.conf.cmd] Deleting file 'include/config/tristate.conf'
  make: Failed to remake makefile 'include/config/auto.conf'.
    SYSTBL  arch/x86/include/generated/asm/syscalls_32.h
    SYSHDR  arch/x86/include/generated/asm/unistd_32_ia32.h
    SYSHDR  arch/x86/include/generated/asm/unistd_64_x32.h
    SYSTBL  arch/x86/include/generated/asm/syscalls_64.h
  [ continue running ... ]

The reason is in the behavior of a pattern rule with multi-targets.

  %/auto.conf %/auto.conf.cmd %/tristate.conf: $(KCONFIG_CONFIG)
          $(Q)$(MAKE) -f $(srctree)/Makefile syncconfig

GNU Make knows this rule is responsible for making all the three files
simultaneously. As far as examined, auto.conf.cmd is the target in
question when this rule is invoked. It is probably because auto.conf.cmd
is included below the inclusion of auto.conf.

The inclusion of auto.conf is mandatory, while that of auto.conf.cmd
is optional. GNU Make does not care about the failure in the process
of updating optional include files.

I filed this issue (https://savannah.gnu.org/bugs/?56301) in case this
behavior could be improved somehow in future releases of GNU Make.
Anyway, it is quite easy to fix our Makefile.

Given that auto.conf is already a mandatory include file, there is no
reason to stick auto.conf.cmd optional. Make it mandatory as well.

Cc: linux-stable <stable@vger.kernel.org> # 5.0+
Fixes: 9390dff66a ("kbuild: invoke syncconfig if include/config/auto.conf.cmd is missing")
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-05-18 11:49:54 +09:00
Masahiro Yamada a149430434 kbuild: add all Clang-specific flags unconditionally
We do not support old Clang versions. Upgrade your clang version
if any of these flags is unsupported.

Let's add all flags inside ifdef CONFIG_CC_IS_CLANG unconditionally.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Sedat Dilek <sedat.dilek@gmail.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
2019-05-18 11:49:53 +09:00
Nathan Chancellor 7eb8e5f073 kbuild: Don't try to add '-fcatch-undefined-behavior' flag
This is no longer a valid option in clang, it was removed in 3.5, which
we don't support.

cb3f812b6b

Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-05-18 11:49:53 +09:00
Masahiro Yamada 8289f913fe kbuild: add -Wvla flag unconditionally
This flag is documented in the GCC 4.6 manual, and recognized by
Clang as well. Let's rip off the cc-option switch.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Sedat Dilek <sedat.dilek@gmail.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Acked-by: Kees Cook <keescook@chromium.org>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
2019-05-18 11:49:52 +09:00