arch: Remove Itanium (IA-64) architecture

The Itanium architecture is obsolete, and an informal survey [0] reveals
that any residual use of Itanium hardware in production is mostly HP-UX
or OpenVMS based. The use of Linux on Itanium appears to be limited to
enthusiasts that occasionally boot a fresh Linux kernel to see whether
things are still working as intended, and perhaps to churn out some
distro packages that are rarely used in practice.

None of the original companies behind Itanium still produce or support
any hardware or software for the architecture, and it is listed as
'Orphaned' in the MAINTAINERS file, as apparently, none of the engineers
that contributed on behalf of those companies (nor anyone else, for that
matter) have been willing to support or maintain the architecture
upstream or even be responsible for applying the odd fix. The Intel
firmware team removed all IA-64 support from the Tianocore/EDK2
reference implementation of EFI in 2018. (Itanium is the original
architecture for which EFI was developed, and the way Linux supports it
deviates significantly from other architectures.) Some distros, such as
Debian and Gentoo, still maintain [unofficial] ia64 ports, but many have
dropped support years ago.

While the argument is being made [1] that there is a 'for the common
good' angle to being able to build and run existing projects such as the
Grid Community Toolkit [2] on Itanium for interoperability testing, the
fact remains that none of those projects are known to be deployed on
Linux/ia64, and very few people actually have access to such a system in
the first place. Even if there were ways imaginable in which Linux/ia64
could be put to good use today, what matters is whether anyone is
actually doing that, and this does not appear to be the case.

There are no emulators widely available, and so boot testing Itanium is
generally infeasible for ordinary contributors. GCC still supports IA-64
but its compile farm [3] no longer has any IA-64 machines. GLIBC would
like to get rid of IA-64 [4] too because it would permit some overdue
code cleanups. In summary, the benefits to the ecosystem of having IA-64
be part of it are mostly theoretical, whereas the maintenance overhead
of keeping it supported is real.

So let's rip off the band aid, and remove the IA-64 arch code entirely.
This follows the timeline proposed by the Debian/ia64 maintainer [5],
which removes support in a controlled manner, leaving IA-64 in a known
good state in the most recent LTS release. Other projects will follow
once the kernel support is removed.

[0] https://lore.kernel.org/all/CAMj1kXFCMh_578jniKpUtx_j8ByHnt=s7S+yQ+vGbKt9ud7+kQ@mail.gmail.com/
[1] https://lore.kernel.org/all/0075883c-7c51-00f5-2c2d-5119c1820410@web.de/
[2] https://gridcf.org/gct-docs/latest/index.html
[3] https://cfarm.tetaneutral.net/machines/list/
[4] https://lore.kernel.org/all/87bkiilpc4.fsf@mid.deneb.enyo.de/
[5] https://lore.kernel.org/all/ff58a3e76e5102c94bb5946d99187b358def688a.camel@physik.fu-berlin.de/

Acked-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

sparc: add asm/stat.h to UAPI compile-test coverage

asm/stat.h is currently excluded from the UAPI compile-test for
ARCH=sparc because of the errors like follows:

In file included from <command-line>:
./usr/include/asm/stat.h:11:2: error: unknown type name 'ino_t'
11 | ino_t st_ino;
| ^~~~~
HDRTEST usr/include/asm/param.h
./usr/include/asm/stat.h:12:2: error: unknown type name 'mode_t'
12 | mode_t st_mode;
| ^~~~~~
./usr/include/asm/stat.h:14:2: error: unknown type name 'uid_t'
14 | uid_t st_uid;
| ^~~~~
./usr/include/asm/stat.h:15:2: error: unknown type name 'gid_t'
15 | gid_t st_gid;
| ^~~~~

The errors can be fixed by prefixing the types with __kernel_.

Then, remove the no-header-test entry from user/include/Makefile.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>

powerpc: add asm/stat.h to UAPI compile-test coverage

asm/stat.h is currently excluded from the UAPI compile-test for
ARCH=powerpc because of the errors like follows:

HDRTEST usr/include/asm/stat.h
In file included from <command-line>:32:
./usr/include/asm/stat.h:32:2: error: unknown type name 'ino_t'
32 | ino_t st_ino;
| ^~~~~
./usr/include/asm/stat.h:35:2: error: unknown type name 'mode_t'
35 | mode_t st_mode;
| ^~~~~~
./usr/include/asm/stat.h:40:2: error: unknown type name 'uid_t'
40 | uid_t st_uid;
| ^~~~~
./usr/include/asm/stat.h:41:2: error: unknown type name 'gid_t'
41 | gid_t st_gid;
| ^~~~~

The errors can be fixed by prefixing the types with __kernel_.

Then, remove the no-header-test entry from user/include/Makefile.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>

mips: add asm/stat.h to UAPI compile-test coverage

asm/stat.h is currently excluded from the UAPI compile-test for
ARCH=mips because of the errors like follows:

HDRTEST usr/include/asm/stat.h
In file included from <command-line>:32:
./usr/include/asm/stat.h:22:2: error: unknown type name 'ino_t'
22 | ino_t st_ino;
| ^~~~~
./usr/include/asm/stat.h:23:2: error: unknown type name 'mode_t'
23 | mode_t st_mode;
| ^~~~~~
./usr/include/asm/stat.h:25:2: error: unknown type name 'uid_t'
25 | uid_t st_uid;
| ^~~~~
./usr/include/asm/stat.h:26:2: error: unknown type name 'gid_t'
26 | gid_t st_gid;
| ^~~~~
./usr/include/asm/stat.h:58:2: error: unknown type name 'mode_t'
58 | mode_t st_mode;
| ^~~~~~
./usr/include/asm/stat.h:61:2: error: unknown type name 'uid_t'
61 | uid_t st_uid;
| ^~~~~
./usr/include/asm/stat.h:62:2: error: unknown type name 'gid_t'
62 | gid_t st_gid;
| ^~~~~

The errors can be fixed by prefixing the types with __kernel_.

Then, remove the no-header-test entry from user/include/Makefile.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>

riscv: add linux/bpf_perf_event.h to UAPI compile-test coverage

I can compile this for ARCH=riscv with CONFIG_UAPI_HEADER_TEST=y.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>

kbuild: prevent exported headers from including <stdlib.h>, <stdbool.h>

Some UAPI headers included <stdlib.h>, like this:

#ifndef __KERNEL__
#include <stdlib.h>
#endif

As it turned out, they just included it for no good reason.

After some fixes, now I can compile-test UAPI headers
(CONFIG_UAPI_HEADER_TEST=y) without including <stdlib.h> from the
system header search paths.

To avoid somebody getting it back again, this commit adds the dummy
header, usr/dummy-include/stdlib.h

I added $(srctree)/usr/dummy-include to the header search paths.
Because it is searched before the system directories, if someone
tries to include <stdlib.h>, they will see the error message.

While I am here, I also replaced $(objtree)/usr/include with $(obj),
but it has no functional change.

If we can make kernel headers self-contained (that is, none of exported
kernel headers includes system headers), we will be able to add the
-nostdinc flag, but that is much far from where we stand now.

As a realistic solution, we can ban header inclusion individually by
putting a dummy header into usr/dummy-include/.

Currently, no header include <stdbool.h>. I put it as well before somebody
attempts to use it.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

kbuild: uapi: use -fsyntax-only rather than -S

The UAPI header tests are checking that the generated headers do not
have syntax errors. There's no need to run the rest of the compilation
pipeline after semantic analysis has run. Replace -S -o /dev/null with
-fsyntax-only.

Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

kbuild: add --target to correctly cross-compile UAPI headers with Clang

When you compile-test UAPI headers (CONFIG_UAPI_HEADER_TEST=y) with
Clang, they are currently compiled for the host target (likely x86_64)
regardless of the given ARCH=.

In fact, some exported headers include libc headers. For example,
include/uapi/linux/agpgart.h includes <stdlib.h> after being exported.
The header search paths should match to the target we are compiling
them for.

Pick up the --target triple from KBUILD_CFLAGS in the same ways as
commit 7f58b487e9ff ("kbuild: make Clang build userprogs for target
architecture").

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

usr/include: replace extra-y with always-y

extra-y is not run for 'make modules'. The header compile test should
be executed irrespective of the build target. always-y is a better fit.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

kbuild: Add environment variables for userprogs flags

Allow additional arguments be passed to userprogs compilation.
Reproducible clang builds need to provide a sysroot and gcc path to
ensure the same toolchain is used across hosts. KCFLAGS is not currently
used for any user programs compilation, so add new USERCFLAGS and
USERLDFLAGS which serves similar purpose as HOSTCFLAGS/HOSTLDFLAGS.

Clang might detect GCC installation on hosts which have it installed
to a default location in /. With addition of these environment
variables, you can specify flags such as:

$ make USERCFLAGS=--sysroot=/path/to/sysroot

This can also be used to specify different sysroots such as musl or
bionic which may be installed on the host in paths that the compiler
may not search by default.

Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Fangrui Song <maskray@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

reiserfs_xattr.h: add linux/reiserfs_xattr.h to UAPI compile-test coverage

linux/reiserfs_xattr.h is currently excluded from the UAPI compile-test
because of the error like follows:

HDRTEST usr/include/linux/reiserfs_xattr.h
In file included from <command-line>:
./usr/include/linux/reiserfs_xattr.h:22:9: error: unknown type name ‘size_t’
22 | size_t length;
| ^~~~~~

The error can be fixed by replacing size_t with __kernel_size_t.

Then, remove the no-header-test entry from user/include/Makefile.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

kexec.h: add linux/kexec.h to UAPI compile-test coverage

linux/kexec.h is currently excluded from the UAPI compile-test because
of the errors like follows:

HDRTEST usr/include/linux/kexec.h
In file included from <command-line>:
./usr/include/linux/kexec.h:56:9: error: unknown type name ‘size_t’
56 | size_t bufsz;
| ^~~~~~
./usr/include/linux/kexec.h:58:9: error: unknown type name ‘size_t’
58 | size_t memsz;
| ^~~~~~

The errors can be fixed by replacing size_t with __kernel_size_t.

Then, remove the no-header-test entry from user/include/Makefile.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

fsmap.h: add linux/fsmap.h to UAPI compile-test coverage

linux/fsmap.h is currently excluded from the UAPI compile-test because
of the error like follows:

HDRTEST usr/include/linux/fsmap.h
In file included from <command-line>:
./usr/include/linux/fsmap.h:72:19: error: unknown type name ‘size_t’
72 | static __inline__ size_t
| ^~~~~~

The error can be fixed by replacing size_t with __kernel_size_t.

Then, remove the no-header-test entry from user/include/Makefile.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

android/binder.h: add linux/android/binder(fs).h to UAPI compile-test coverage

linux/android/binder.h and linux/android/binderfs.h are currently
excluded from the UAPI compile-test because of the errors like follows:

HDRTEST usr/include/linux/android/binder.h
In file included from <command-line>:
./usr/include/linux/android/binder.h:291:9: error: unknown type name ‘pid_t’
291 | pid_t sender_pid;
| ^~~~~
./usr/include/linux/android/binder.h:292:9: error: unknown type name ‘uid_t’
292 | uid_t sender_euid;
| ^~~~~

The errors can be fixed by replacing {pid,uid}_t with __kernel_{pid,uid}_t.

Then, remove the no-header-test entries from user/include/Makefile.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

shmbuf.h: add asm/shmbuf.h to UAPI compile-test coverage

asm/shmbuf.h is currently excluded from the UAPI compile-test because of
the errors like follows:

HDRTEST usr/include/asm/shmbuf.h
In file included from ./usr/include/asm/shmbuf.h:6,
from <command-line>:
./usr/include/asm-generic/shmbuf.h:26:33: error: field ‘shm_perm’ has incomplete type
26 | struct ipc64_perm shm_perm; /* operation perms */
| ^~~~~~~~
./usr/include/asm-generic/shmbuf.h:27:9: error: unknown type name ‘size_t’
27 | size_t shm_segsz; /* size of segment (bytes) */
| ^~~~~~
./usr/include/asm-generic/shmbuf.h:40:9: error: unknown type name ‘__kernel_pid_t’
40 | __kernel_pid_t shm_cpid; /* pid of creator */
| ^~~~~~~~~~~~~~
./usr/include/asm-generic/shmbuf.h:41:9: error: unknown type name ‘__kernel_pid_t’
41 | __kernel_pid_t shm_lpid; /* pid of last operator */
| ^~~~~~~~~~~~~~

The errors can be fixed by replacing size_t with __kernel_size_t and by
including proper headers.

Then, remove the no-header-test entry from user/include/Makefile.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

signal.h: add linux/signal.h and asm/signal.h to UAPI compile-test coverage

linux/signal.h and asm/signal.h are currently excluded from the UAPI
compile-test because of the errors like follows:

HDRTEST usr/include/asm/signal.h
In file included from <command-line>:
./usr/include/asm/signal.h:103:9: error: unknown type name ‘size_t’
103 | size_t ss_size;
| ^~~~~~

The errors can be fixed by replacing size_t with __kernel_size_t.

Then, remove the no-header-test entries from user/include/Makefile.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

kbuild: remove include/linux/cyclades.h from header file check

The file now rightfully throws up a big warning that it should never be
included, so remove it from the header_check test.

Fixes: f23653fe6447 ("tty: Partially revert the removal of the Cyclades public API")
Cc: stable <stable@vger.kernel.org>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: "Maciej W. Rozycki" <macro@embecosm.com>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/r/20220127073304.42399-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usr/include/Makefile: add linux/nfc.h to the compile-test coverage

As linux/nfc.h userspace compilation was finally fixed by commits
79b69a83705e ("nfc: uapi: use kernel size_t to fix user-space builds")
and 7175f02c4e5f ("uapi: fix linux/nfc.h userspace compilation errors"),
there is no need to keep the compile-test exception for it in
usr/include/Makefile.

Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

kbuild: move headers_check.pl to usr/include/

This script is only used by usr/include/Makefile. Make it local to
the directory.

Update the comment in include/uapi/linux/soundcard.h because
'make headers_check' is no longer functional.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

arch: ia64: Remove rest of perfmon support

Perfmon support (used by oprofile earlier) was removed by commit
ecf5b72d5f66 ("ia64: Remove perfmon") earlier, but it missed few files
to remove/update.

Clean it up.

Suggested-by: Arnd Bergmann <arnd@kernel.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Robert Richter <rric@kernel.org>
Acked-by: William Cohen <wcohen@redhat.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: Thomas Gleixner <tglx@linutronix.de>

unexport linux/elfcore.h

It's unusable from userland - it uses elf_gregset_t, which is not
provided by exported headers. glibc has it in sys/procfs.h, but
the same file defines struct elf_prstatus, so linux/elfcore.h can't
be included once sys/procfs.h has been pulled. Same goes for uclibc
and dietlibc simply doesn't have elf_gregset_t defined anywhere.

IOW, no userland source is including that thing.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

bpfilter: match bit size of bpfilter_umh to that of the kernel

bpfilter_umh is built for the default machine bit of the compiler,
which may not match to the bit size of the kernel.

This happens in the scenario below:

You can use biarch GCC that defaults to 64-bit for building the 32-bit
kernel. In this case, Kbuild passes -m32 to teach the compiler to
produce 32-bit kernel space objects. However, it is missing when
building bpfilter_umh. It is built as a 64-bit ELF, and then embedded
into the 32-bit kernel.

The 32-bit kernel and 64-bit umh is a bad combination.

In theory, we can have 32-bit umh running on 64-bit kernel, but we do
not have a good reason to support such a usecase.

The best is to match the bit size between them.

Pass -m32 or -m64 to the umh build command if it is found in
$(KBUILD_CFLAGS). Evaluate CC_CAN_LINK against the kernel bit-size.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

kbuild: use -MMD instead of -MD to exclude system headers from dependency

This omits system headers from the generated header dependency.

System headers are not updated unless you upgrade the compiler. Nor do
they contain CONFIG options, so fixdep does not need to parse them.

Having said that, the effect of this optimization will be quite small
because the kernel code generally does not include system headers
except <stdarg.h>. Host programs include a lot of system headers,
but there are not so many in the kernel tree.

At first, keeping system headers in .*.cmd files might be useful to
detect the compiler update, but there is no guarantee that <stdarg.h>
is included from every file. So, I implemented a more reliable way in
the previous commit.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

kbuild: fix comment about missing include guard detection

The keyword here is 'twice' to explain the trick.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

kbuild: rename header-test- to no-header-test in usr/include/Makefile

Since commit d2a99dbdade4 ("kbuild: update compile-test header list for
v5.5-rc1"), this does not depend on any CONFIG option.

no-header-test is clearer.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

kbuild: detect missing include guard for exported headers

Adding an include guard to every header file is good practice in case
it is included multiple times.

Exported headers are compile-tested for the comprehensive sanity checks.
Let's include the same header twice. If an include guard is missing,
the header will fail to build due to redefinition of something.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>

kbuild: fix 'No such file or directory' warning when cleaning

Since commit fcbb8461fd23 ("kbuild: remove header compile test"),
'make clean' with O= option in the pristine source tree emits
'No such file or directory' warning.

$ git clean -d -f -x
$ make O=foo clean
make[1]: Entering directory '/home/masahiro/linux/foo'
find: ‘usr/include’: No such file or directory
make[1]: Leaving directory '/home/masahiro/linux/foo'

Fixes: fcbb8461fd23 ("kbuild: remove header compile test")
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

arch: sembuf.h: make uapi asm/sembuf.h self-contained

Userspace cannot compile <asm/sembuf.h> due to some missing type
definitions. For example, building it for x86 fails as follows:

CC usr/include/asm/sembuf.h.s
In file included from <command-line>:32:0:
usr/include/asm/sembuf.h:17:20: error: field `sem_perm' has incomplete type
struct ipc64_perm sem_perm; /* permissions .. see ipc.h */
^~~~~~~~
usr/include/asm/sembuf.h:24:2: error: unknown type name `__kernel_time_t'
__kernel_time_t sem_otime; /* last semop time */
^~~~~~~~~~~~~~~
usr/include/asm/sembuf.h:25:2: error: unknown type name `__kernel_ulong_t'
__kernel_ulong_t __unused1;
^~~~~~~~~~~~~~~~
usr/include/asm/sembuf.h:26:2: error: unknown type name `__kernel_time_t'
__kernel_time_t sem_ctime; /* last change time */
^~~~~~~~~~~~~~~
usr/include/asm/sembuf.h:27:2: error: unknown type name `__kernel_ulong_t'
__kernel_ulong_t __unused2;
^~~~~~~~~~~~~~~~
usr/include/asm/sembuf.h:29:2: error: unknown type name `__kernel_ulong_t'
__kernel_ulong_t sem_nsems; /* no. of semaphores in array */
^~~~~~~~~~~~~~~~
usr/include/asm/sembuf.h:30:2: error: unknown type name `__kernel_ulong_t'
__kernel_ulong_t __unused3;
^~~~~~~~~~~~~~~~
usr/include/asm/sembuf.h:31:2: error: unknown type name `__kernel_ulong_t'
__kernel_ulong_t __unused4;
^~~~~~~~~~~~~~~~

It is just a matter of missing include directive.

Include <asm/ipcbuf.h> to make it self-contained, and add it to
the compile-test coverage.

Link: http://lkml.kernel.org/r/20191030063855.9989-3-yamada.masahiro@socionext.com
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch: msgbuf.h: make uapi asm/msgbuf.h self-contained

Userspace cannot compile <asm/msgbuf.h> due to some missing type
definitions. For example, building it for x86 fails as follows:

CC usr/include/asm/msgbuf.h.s
In file included from usr/include/asm/msgbuf.h:6:0,
from <command-line>:32:
usr/include/asm-generic/msgbuf.h:25:20: error: field `msg_perm' has incomplete type
struct ipc64_perm msg_perm;
^~~~~~~~
usr/include/asm-generic/msgbuf.h:27:2: error: unknown type name `__kernel_time_t'
__kernel_time_t msg_stime; /* last msgsnd time */
^~~~~~~~~~~~~~~
usr/include/asm-generic/msgbuf.h:28:2: error: unknown type name `__kernel_time_t'
__kernel_time_t msg_rtime; /* last msgrcv time */
^~~~~~~~~~~~~~~
usr/include/asm-generic/msgbuf.h:29:2: error: unknown type name `__kernel_time_t'
__kernel_time_t msg_ctime; /* last change time */
^~~~~~~~~~~~~~~
usr/include/asm-generic/msgbuf.h:41:2: error: unknown type name `__kernel_pid_t'
__kernel_pid_t msg_lspid; /* pid of last msgsnd */
^~~~~~~~~~~~~~
usr/include/asm-generic/msgbuf.h:42:2: error: unknown type name `__kernel_pid_t'
__kernel_pid_t msg_lrpid; /* last receive pid */
^~~~~~~~~~~~~~

It is just a matter of missing include directive.

Include <asm/ipcbuf.h> to make it self-contained, and add it to
the compile-test coverage.

Link: http://lkml.kernel.org/r/20191030063855.9989-2-yamada.masahiro@socionext.com
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch: ipcbuf.h: make uapi asm/ipcbuf.h self-contained

Userspace cannot compile <asm/ipcbuf.h> due to some missing type
definitions. For example, building it for x86 fails as follows:

CC usr/include/asm/ipcbuf.h.s
In file included from usr/include/asm/ipcbuf.h:1:0,
from <command-line>:32:
usr/include/asm-generic/ipcbuf.h:21:2: error: unknown type name `__kernel_key_t'
__kernel_key_t key;
^~~~~~~~~~~~~~
usr/include/asm-generic/ipcbuf.h:22:2: error: unknown type name `__kernel_uid32_t'
__kernel_uid32_t uid;
^~~~~~~~~~~~~~~~
usr/include/asm-generic/ipcbuf.h:23:2: error: unknown type name `__kernel_gid32_t'
__kernel_gid32_t gid;
^~~~~~~~~~~~~~~~
usr/include/asm-generic/ipcbuf.h:24:2: error: unknown type name `__kernel_uid32_t'
__kernel_uid32_t cuid;
^~~~~~~~~~~~~~~~
usr/include/asm-generic/ipcbuf.h:25:2: error: unknown type name `__kernel_gid32_t'
__kernel_gid32_t cgid;
^~~~~~~~~~~~~~~~
usr/include/asm-generic/ipcbuf.h:26:2: error: unknown type name `__kernel_mode_t'
__kernel_mode_t mode;
^~~~~~~~~~~~~~~
usr/include/asm-generic/ipcbuf.h:28:35: error: `__kernel_mode_t' undeclared here (not in a function)
unsigned char __pad1[4 - sizeof(__kernel_mode_t)];
^~~~~~~~~~~~~~~
usr/include/asm-generic/ipcbuf.h:31:2: error: unknown type name `__kernel_ulong_t'
__kernel_ulong_t __unused1;
^~~~~~~~~~~~~~~~
usr/include/asm-generic/ipcbuf.h:32:2: error: unknown type name `__kernel_ulong_t'
__kernel_ulong_t __unused2;
^~~~~~~~~~~~~~~~

It is just a matter of missing include directive.

Include <linux/posix_types.h> to make it self-contained, and add it to
the compile-test coverage.

Link: http://lkml.kernel.org/r/20191030063855.9989-1-yamada.masahiro@socionext.com
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

linux/scc.h: make uapi linux/scc.h self-contained

Userspace cannot compile <linux/scc.h>

CC usr/include/linux/scc.h.s
In file included from <command-line>:32:0:
usr/include/linux/scc.h:20:20: error: `SIOCDEVPRIVATE' undeclared here (not in a function)
SIOCSCCRESERVED = SIOCDEVPRIVATE,
^~~~~~~~~~~~~~

Include <linux/sockios.h> to make it self-contained, and add it to the
compile-test coverage.

Link: http://lkml.kernel.org/r/20191108055809.26969-1-yamada.masahiro@socionext.com
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kbuild: move headers_check rule to usr/include/Makefile

Currently, some sanity checks for uapi headers are done by
scripts/headers_check.pl, which is wired up to the 'headers_check'
target in the top Makefile.

It is true compiling headers has better test coverage, but there
are still several headers excluded from the compile test. I like
to keep headers_check.pl for a while, but we can delete a lot of
code by moving the build rule to usr/include/Makefile.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

kbuild: remove header compile test

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: Masahiro Yamada <yamada.masahiro@socionext.com>

kbuild: update compile-test header list for v5.5-rc1

Since commit 707816c8b050 ("netfilter: remove deprecation warnings from
uapi headers."), you can compile linux/netfilter_ipv4/ipt_LOG.h and
linux/netfilter_ipv6/ip6t_LOG.h without warnings.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

kbuild: update compile-test header list for v5.4-rc2

Commit 6dc280ebeed2 ("coda: remove uapi/linux/coda_psdev.h") removed
a header in question. Some more build errors were fixed. Add more
headers into the test coverage.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

netfilter: ebtables: use __u8 instead of uint8_t in uapi header

When CONFIG_UAPI_HEADER_TEST=y, exported headers are compile-tested to
make sure they can be included from user-space.

Currently, linux/netfilter_bridge/ebtables.h is excluded from the test
coverage. To make it join the compile-test, we need to fix the build
errors attached below.

For a case like this, we decided to use __u{8,16,32,64} variable types
in this discussion:

https://lkml.org/lkml/2019/6/5/18

Build log:

CC usr/include/linux/netfilter_bridge/ebtables.h.s
In file included from <command-line>:32:0:
./usr/include/linux/netfilter_bridge/ebtables.h:126:4: error: unknown type name ‘uint8_t’
uint8_t revision;
^~~~~~~
./usr/include/linux/netfilter_bridge/ebtables.h:139:4: error: unknown type name ‘uint8_t’
uint8_t revision;
^~~~~~~
./usr/include/linux/netfilter_bridge/ebtables.h:152:4: error: unknown type name ‘uint8_t’
uint8_t revision;
^~~~~~~

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

kbuild: remove clean-dirs syntax

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: Masahiro Yamada <yamada.masahiro@socionext.com>

kbuild: enable arch/s390/include/uapi/asm/zcrypt.h for uapi header test

Masahiro Yamada changed the zcrypt.h header file to use __u{16,32,64}
instead of uint{16,32,64}_t with ("s390: use __u{16,32,64} instead of
uint{16,32,64}_t in uapi header").

This makes all s390 header files pass - remove zcrypt.h from the blacklist.

Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>

kbuild: update compile-test header list for v5.3-rc1

- Some headers graduated from the blacklist

- hyperv_timer.h joined the header-test when CONFIG_X86=y

- nf_tables*.h joined the header-test when CONFIG_NF_TABLES is
enabled.

- The entry for nf_tables_offload.h was added to fix build error for
the combination of CONFIG_NF_TABLES=n and CONFIG_KERNEL_HEADER_TEST=y.

- The entry for iomap.h was added because this header is supposed to
be included only when CONFIG_BLOCK=y

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

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>