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 7f58b487

 ("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>

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>

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>

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>

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>

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>

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>

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>

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>

cmd_copy and cmd_shipped have similar functionality. The difference is
that cmd_copy uses 'cp' while cmd_shipped 'cat'.

Unify them into cmd_copy because this macro name is more intuitive.

Going forward, cmd_copy will use 'cat' to avoid the permission issue.
I also thought of 'cp --no-preserve=mode' but this option is not
mentioned in the POSIX spec [1], so I am keeping the 'cat' command.

[1]: https://pubs.opengroup.org/onlinepubs/009695299/utilities/cp.html


Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Gabriel Krisman Bertazi <krisman@collabora.com>

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

Fixes: f23653fe

 ("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>

As linux/nfc.h userspace compilation was finally fixed by commits
79b69a83 ("nfc: uapi: use kernel size_t to fix user-space builds")
and 7175f02c

 ("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>

GZIP-compressed files end with 4 byte data that represents the size
of the original input. The decompressors (the self-extracting kernel)
exploit it to know the vmlinux size beforehand. To mimic the GZIP's
trailer, Kbuild provides cmd_{bzip2,lzma,lzo,lz4,xzkern,zstd22}.
Unfortunately these macros are used everywhere despite the appended
size data is only useful for the decompressors.

There is no guarantee that such hand-crafted trailers are safely ignored.
In fact, the kernel refuses compressed initramdfs with the garbage data.
That is why usr/Makefile overrides size_append to make it no-op.

To limit the use of such broken compressed files, this commit renames
the existing macros as follows:

  cmd_bzip2   --> cmd_bzip2_with_size
  cmd_lzma    --> cmd_lzma_with_size
  cmd_lzo     --> cmd_lzo_with_size
  cmd_lz4     --> cmd_lz4_with_size
  cmd_xzkern  --> cmd_xzkern_with_size
  cmd_zstd22  --> cmd_zstd22_with_size

To keep the decompressors working, I...

The previous commit fixed up all shell scripts to not include
include/config/auto.conf.

Now that include/config/auto.conf is only included by Makefiles,
we can change it into a more Make-friendly form.

Previously, Kconfig output string values enclosed with double-quotes
(both in the .config and include/config/auto.conf):

    CONFIG_X="foo bar"

Unlike shell, Make handles double-quotes (and single-quotes as well)
verbatim. We must rip them off when used.

There are some patterns:

  [1] $(patsubst "%",%,$(CONFIG_X))
  [2] $(CONFIG_X:"%"=%)
  [3] $(subst ",,$(CONFIG_X))
  [4] $(shell echo $(CONFIG_X))

These are not only ugly, but also fragile.

[1] and [2] do not work if the value contains spaces, like
   CONFIG_X=" foo bar "

[3] does not work correctly if the value contains double-quotes like
   CONFIG_X="foo\"bar"

[4] seems to work better, but has a cost of forking a process.

Anyway, quoted strings were always PITA for our Makefiles.

T...

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>

Cpio format reserves 8 bytes for an ASCII representation of a time_t timestamp.
While 2106-02-07 06:28:15 UTC (time_t = 0xffffffff) is still some years in the
future, a poorly chosen date string for KBUILD_BUILD_TIMESTAMP, converted into
seconds since the epoch, might lead to exceeded cpio timestamp limits that
result in a broken cpio archive.  Add timestamp checks to prevent overrun of
the 8-byte cpio header field.

My colleague Thomas Kühnel discovered the behaviour, when we accidentally fed
SOURCE_DATE_EPOCH to KBUILD_BUILD_TIMESTAMP as is: some timestamps (e.g.
1607420928 = 2021-12-08 9:48:48 UTC) will be interpreted by `date` as a valid
date specification of science fictional times (here: year 160742).  Even though
this is bad input for KBUILD_BUILD_TIMESTAMP, it should not break the initramfs
cpio format.

Signed-off-by: Nicolas Schier <nicolas@fjasle.eu>
Cc: Thomas Kühnel <thomas.kuehnel@avm.de>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Add 'const' to constant arrays. I also added missing 'static'.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>

The pattern prefixed with '/' matches files in the same directory,
but not ones in sub-directories.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Miguel Ojeda <ojeda@kernel.org>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Andra Paraschiv <andraprs@amazon.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Gabriel Krisman Bertazi <krisman@collabora.com>

LANG gives a weak default to each LC_* in case it is not explicitly
defined. LC_ALL, if set, overrides all other LC_* variables.

  LANG  <  LC_CTYPE, LC_COLLATE, LC_MONETARY, LC_NUMERIC, ...  <  LC_ALL

This is why documentation such as [1] suggests to set LC_ALL in build
scripts to get the deterministic result.

LANG=C is not strong enough to override LC_* that may be set by end
users.

[1]: https://reproducible-builds.org/docs/locales/



Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Reviewed-by: Matthias Maennich <maennich@google.com>
Acked-by: Matthieu Baerts <matthieu.baerts@tessares.net> (mptcp)
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The current .gitignore intends to ignore everything under usr/include/
except .gitignore and Makefile.

A cleaner solution is to use a pattern suffixed with '/', which matches
only directories. It works well here because all the exported headers
are located in sub-directories, like <linux/*.h>, <asm/*.h>.

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

Commit be1859bd ("initramfs: remove redundant dependency on
BLK_DEV_INITRD") removed all redundant dependencies on BLK_DEV_INITRD,
but the recent addition of zstd support introduced a new one.

Fixes: a30d8a39

 ("usr: Add support for zstd compressed initramfs")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Perfmon support (used by oprofile earlier) was removed by commit
ecf5b72d

 ("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>

- Add support for a zstd compressed initramfs.

- Add compression for compressing built-in initramfs with zstd.

I have tested this patch by boot testing with buildroot and QEMU.
Specifically, I booted the kernel with both a zstd and gzip compressed
initramfs, both built into the kernel and separate. I ensured that the
correct compression algorithm was used. I tested on arm, aarch64, i386,
and x86_64.

This patch has been tested in production on aarch64 and x86_64 devices.

Additionally, I have performance measurements from internal use in
production. On an aarch64 device we saw 19 second boot time improvement
from switching from lzma to zstd (27 seconds to 8 seconds). On an x86_64
device we saw a 9 second boot time reduction from switching from xz to
zstd.

Signed-off-by: Nick Terrell <terrelln@fb.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore...

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_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>

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>

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

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

Add SPDX License Identifier to all .gitignore files.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Even though INITRAMFS_SOURCE kconfig option isn't set in most of
defconfigs it is used (set) extensively by various build systems.
Commit f26661e1

 ("initramfs: make initramfs compression choice
non-optional") has changed default compression mode. Previously we
compress initramfs using available compression algorithm. Now
we don't use any compression at all by default.
It significantly increases the image size in case of build system
chooses embedded initramfs. Initially I faced with this issue while
using buildroot.

As of today it's not possible to set preferred compression mode
in target defconfig as this option depends on INITRAMFS_SOURCE
being set. Modification of all build systems either doesn't look
like good option.

Let's instead rewrite initramfs compression mode choices list
the way that "INITRAMFS_COMPRESSION_NONE" will be the last option
in the list. In that case it will be chosen only if all other
options (which implements any compression) are not available.

Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Since commit ddd09bcc ("initramfs: make compression options not
depend on INITRAMFS_SOURCE"), Kconfig asks the compression mode for
the built-in initramfs regardless of INITRAMFS_SOURCE.

It is technically simpler, but pointless from a UI perspective,
Linus says [1].

When INITRAMFS_SOURCE is empty, usr/Makefile creates a tiny default
cpio, which is so small that nobody cares about the compression.

This commit hides the Kconfig choice in that case. The default cpio
is embedded without compression, which was the original behavior.

[1]: https://lkml.org/lkml/2020/2/1/160



Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

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: Masahiro Yamada <masahiroy@kernel.org>

This script sets the -e option, so it exits on any error, in which
case it exits without cleaning up the intermediate cpio_list.

Make sure to delete it on exit.

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

Currently, usr/gen_initramfs.sh takes care of all the use-cases:

 [1] generates a cpio file unless CONFIG_INITRAMFS_SOURCE points to
     a single cpio archive

 [2] If CONFIG_INITRAMFS_SOURCE is the path to a cpio archive,
     use it as-is.

 [3] Compress the cpio file according to CONFIG_INITRAMFS_COMPRESSION_*
     unless it is passed a compressed archive.

To simplify the script, move [2] and [3] to usr/Makefile.

If CONFIG_INITRAMFS_SOURCE is the path to a cpio archive, there is
no need to run this shell script.

For the cpio archive compression, you can re-use the rules from
scripts/Makefile.lib .

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

Currently, this script outputs a cpio file when -o option is
given, but otherwise a text file in the format recognized by
gen_init_cpio.

This behavior is unclear. Make it always output a cpio file.

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

When CONFIG_INITRAMFS_SOURCE is empty, the Makefile passes the -d
option to gen_initramfs.sh to create the default initramfs, which
contains /dev, /dev/console, and /root.

This commit simplifies the default behavior; remove the -d option,
and add the default cpio list.

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

Currently, this script is run twice, for the dependency list, and then
for the cpio archive.

The first one is re-run every time although its build log is suppressed
so nobody notices it.

Make it work more efficiently by generating the cpio and the dependency
list at the same time.

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

Specify the dependency directly in the Makefile.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Greg Thelen <gthelen@google.com>

Currently, the choice of the initramfs compression mode is too complex
because users are allowed to not specify the compression mode at all.

I think it makes more sense to require users to choose the compression
mode explicitly, and delete the fallback defaults of INITRAMFS_COMPRESSION.

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

Even if INITRAMFS_SOURCE is empty, usr/gen_initramfs.sh generates a
tiny default initramfs, which is embedded in vmlinux.

So, defining INITRAMFS_COMPRESSION* options should be valid irrespective
of INITRAMFS_SOURCE.

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

init/Kconfig includes usr/Kconfig inside the "if BLK_DEV_INITRD" ...
"endif" block:

    if BLK_DEV_INITRD

    source "usr/Kconfig"

    endif

Hence, all the defines in usr/Kconfig depend on BLK_DEV_INITRD.

Remove the redundant "depends on BLK_DEV_INITRD".

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Greg Thelen <gthelen@google.com>