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

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

As Documentation/kbuild/llvm.rst implies, building the kernel with a
full set of LLVM tools gets very verbose and unwieldy.

Provide a single switch LLVM=1 to use Clang and LLVM tools instead
of GCC and Binutils. You can pass it from the command line or as an
environment variable.

Please note LLVM=1 does not turn on the integrated assembler. You need
to pass LLVM_IAS=1 to use it. When the upstream kernel is ready for the
integrated assembler, I think we can make it default.

We discussed what we need, and we agreed to go with a simple boolean
flag that switches both target and host tools:

  https://lkml.org/lkml/2020/3/28/494
  https://lkml.org/lkml/2020/4/3/43

Some items discussed, but not adopted:

- LLVM_DIR

  When multiple versions of LLVM are installed, I just thought supporting
  LLVM_DIR=/path/to/my/llvm/bin/ might be useful.

  CC      = $(LLVM_DIR)clang
  LD      = $(LLVM_DIR)ld.lld
    ...

  However, we can handle this by modifying PATH. So, we decided to not do
  this.

- LLVM_SUFFIX

  Some distributions (e.g. Debian) package specific versions of LLVM with
  naming conventions that use the version as a suffix.

  CC      = clang$(LLVM_SUFFIX)
  LD      = ld.lld(LLVM_SUFFIX)
    ...

  will allow a user to pass LLVM_SUFFIX=-11 to use clang-11 etc.,
  but the suffixed versions in /usr/bin/ are symlinks to binaries in
  /usr/lib/llvm-#/bin/, so this can also be handled by PATH.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Tested-by: Nathan Chancellor <natechancellor@gmail.com> # build
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

The 'AS' variable is unused for building the kernel. Only the remaining
usage is to turn on the integrated assembler. A boolean flag is a better
fit for this purpose.

AS=clang was added for experts. So, I replaced it with LLVM_IAS=1,
breaking the backward compatibility.

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

Staring v4.18, Kconfig evaluates compiler capabilities, and hides CONFIG
options your compiler does not support. This works well if you configure
and build the kernel on the same host machine.

It is inconvenient if you prepare the .config that is carried to a
different build environment (typically this happens when you package
the kernel for distros) because using a different compiler potentially
produces different CONFIG options than the real build environment.
So, you probably want to make as many options visible as possible.
In other words, you need to create a super-set of CONFIG options that
cover any build environment. If some of the CONFIG options turned out
to be unsupported on the build machine, they are automatically disabled
by the nature of Kconfig.

However, it is not feasible to get a full-featured compiler for every
arch.

This issue was discussed here:

  https://lkml.org/lkml/2019/12/9/620

Other than distros, savedefconfig is also a problem. Some arch sub-systems
periodically resync defconfig files. If you use a less-capable compiler
for savedefconfig, options that do not meet 'depends on $(cc-option,...)'
will be forcibly disabled. So, 'make defconfig && make savedefconfig'
may silently change the behavior.

This commit adds a set of dummy toolchains that pretend to support any
feature.

Most of compiler features are tested by cc-option, which simply checks
the exit code of $(CC). The dummy tools are shell scripts that always
exit with 0. So, $(cc-option, ...) is evaluated as 'y'.

There are more complicated checks such as:

  scripts/gcc-x86_{32,64}-has-stack-protector.sh
  scripts/gcc-plugin.sh
  scripts/tools-support-relr.sh

scripts/dummy-tools/gcc passes all checks.

From the top directory of the source tree, you can do:

   $ make CROSS_COMPILE=scripts/dummy-tools/ oldconfig

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Philipp Rudo <prudo@linux.ibm.com>
Tested-by: Jeremy Cline <jcline@redhat.com>

Kbuild supports not only obj-y but also lib-y to list objects linked to
vmlinux.

The difference between them is that all the objects from obj-y are
forcibly linked to vmlinux, whereas the objects from lib-y are linked
as needed; if there is no user of a lib-y object, it is not linked.

lib-y is intended to list utility functions that may be called from all
over the place (and may be unused at all), but it is a problem for
EXPORT_SYMBOL(). Even if there is no call-site in the vmlinux, we need
to keep exported symbols for the use from loadable modules.

Commit 7f2084fa

 ("[kbuild] handle exports in lib-y objects reliably")
worked around it by linking a dummy object, lib-ksyms.o, which contains
references to all the symbols exported from lib.a in that directory.
It uses the linker script command, EXTERN. Unfortunately, the meaning of
EXTERN of ld.lld is different from that of ld.bfd. Therefore, this does
not work with LD=ld.lld (CBL issue #515).

Anyway, the build rule of lib-ksyms.o is somewhat tricky. So, I want to
get rid of it.

At first, I was thinking of accumulating lib-y objects into obj-y
(or even replacing lib-y with obj-y entirely), but the lib-y syntax
is used beyond the ordinary use in lib/ and arch/*/lib/.

Examples:

 - drivers/firmware/efi/libstub/Makefile builds lib.a, which is linked
   into vmlinux in the own way (arm64), or linked to the decompressor
   (arm, x86).

 - arch/alpha/lib/Makefile builds lib.a which is linked not only to
   vmlinux, but also to bootloaders in arch/alpha/boot/Makefile.

 - arch/xtensa/boot/lib/Makefile builds lib.a for use from
   arch/xtensa/boot/boot-redboot/Makefile.

One more thing, adding everything to obj-y would increase the vmlinux
size of allnoconfig (or tinyconfig).

For less impact, I tweaked the destination of lib.a at the top Makefile;
when CONFIG_MODULES=y, lib.a goes to KBUILD_VMLINUX_OBJS, which is
forcibly linked to vmlinux, otherwise lib.a goes to KBUILD_VMLINUX_LIBS
as before.

The size impact for normal usecases is quite small since at lease one
symbol in every lib-y object is eventually called by someone. In case
you are intrested, here are the figures.

x86_64_defconfig:

   text	   data	    bss	    dec	    hex	filename
19566602 5422072 1589328 26578002 1958c52 vmlinux.before
19566932 5422104 1589328 26578364 1958dbc vmlinux.after

The case with the biggest impact is allnoconfig + CONFIG_MODULES=y.

ARCH=x86 allnoconfig + CONFIG_MODULES=y:

   text	   data	    bss	    dec	    hex	filename
1175162	 254740	1220608	2650510	 28718e	vmlinux.before
1177974	 254836	1220608	2653418	 287cea	vmlinux.after

Hopefully this is still not a big deal. The per-file trimming with the
static library is not so effective after all.

If fine-grained optimization is desired, some architectures support
CONFIG_LD_DEAD_CODE_DATA_ELIMINATION, which trims dead code per-symbol
basis. When LTO is supported in mainline, even better optimization will
be possible.

Link: https://github.com/ClangBuiltLinux/linux/issues/515
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reported-by: kbuild test robot <lkp@intel.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

As far as I understood, prom_meminit() in arch/mips/fw/arc/memory.c
is overridden by the one in arch/mips/sgi-ip32/ip32-memory.c if
CONFIG_SGI_IP32 is enabled.

The use of EXPORT_SYMBOL in static libraries potentially causes a
problem for the llvm linker [1]. So, I want to forcibly link lib-y
objects to vmlinux when CONFIG_MODULES=y.

As a groundwork, we must fix multiple definitions that have previously
been hidden by lib-y.

The prom_cleanup() in this file is already marked as __weak (because
it is overridden by the one in arch/mips/sgi-ip22/ip22-mc.c).
I think it should be OK to do the same for these two.

[1]: https://github.com/ClangBuiltLinux/linux/issues/515

Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-By: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

I do not like to add an extra include path for every tool with no
good reason. This should be specified per file.

This line was added by commit 6520fe55

 ("x86, realmode: 16-bit
real-mode code support for relocs tool"), which did not touch
anything else in scripts/. I see no reason to add this.

Also, remove the comment about kallsyms because we do not have any
for the rest of programs.

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

scripts/mkcompile_h uses $(CC) only for getting the version string.

I suspected there was a specific reason why the additional flags were
needed, and dug the commit history. This code dates back to at least
2002 [1], but I could not get any more clue.

Just get rid of it.

[1]: https://git.kernel.org/pub/scm/linux/kernel/git/history/history.git/commit/?id=29f3df7eba8ddf91a55183f9967f76fbcc3ab742

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>

The tool is called llvm-size, not llvm-objsize.

Fixes: fcf1b6a3

 ("Documentation/llvm: add documentation on building w/ Clang/LLVM")
Signed-off-by: Fangrui Song <maskray@google.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

When doing Clang builds of the kernel, it is possible to link with
either ld.bfd (binutils) or ld.lld (LLVM), but it is not possible to
discover this from a running kernel. Add the "$LD -v" output to
/proc/version.

Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Tested-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Fangrui Song <maskray@google.com>
Reviewed-by: Sedat Dilek <sedat.dilek@gmail.com>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

There are a few items with wrong alignments. Solve them.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

The items described on those TODOs are already solved. So,
remove the comments.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

At least on my tests (building against Qt5.13), it seems to
me that, since Kernel 3.14, the split view mode is broken.

Maybe it was not a top priority during the conversion time.

Anyway, this patch changes the logic in order to properly
support the split view mode and the single view mode.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

The port to Qt5 tried to preserve the same way as it used
to work with Qt3 and Qt4. However, at least with newer
versions of Qt5 (5.13), this doesn't work properly.

Change the schema by adding a vertical layout, in order
for it to start working properly again.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Both main config window and the item window have "Option"
name. That sounds weird, and makes harder to debug issues
of a window appearing at the wrong place.

So, change the title to reflect the contents of each
window.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

The recommended way to initialize a null string is with
QString(). This is there at least since Qt5.5, with is
when qconf was ported to Qt5.

Fix those warnings:

	scripts/kconfig/qconf.cc: In member function ‘void ConfigItem::updateMenu()’:
	scripts/kconfig/qconf.cc:158:31: warning: ‘QString::null’ is deprecated: use QString() [-Wdeprecated-declarations]
	  158 |    setText(noColIdx, QString::null);
	      |                               ^~~~
	In file included from /usr/include/qt5/QtCore/qobject.h:47,
	                 from /usr/include/qt5/QtWidgets/qwidget.h:45,
	                 from /usr/include/qt5/QtWidgets/qmainwindow.h:44,
	                 from /usr/include/qt5/QtWidgets/QMainWindow:1,
	                 from scripts/kconfig/qconf.cc:9:

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Nobody was opposed to raising minimum GCC version to 4.8 [1]
So, we will drop GCC <= 4.7 support sooner or later.

We always use C++ compiler for building plugins for GCC >= 4.8.

This commit drops the plugin support for GCC <= 4.7 a bit earlier,
which allows us to dump lots of code.

[1] https://lkml.org/lkml/2020/1/23/545

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Kees Cook <keescook@chromium.org>

Currently, we disable -Wtautological-compare, which in turn disables a
bunch of more specific tautological comparison warnings that are useful
for the kernel such as -Wtautological-bitwise-compare. See clang's
documentation below for the other warnings that are suppressed by
-Wtautological-compare. Now that all of the major/noisy warnings have
been fixed, enable -Wtautological-compare so that more issues can be
caught at build time by various continuous integration setups.

-Wtautological-constant-out-of-range-compare is kept disabled under a
normal build but visible at W=1 because there are places in the kernel
where a constant or variable size can change based on the kernel
configuration. These are not fixed in a clean/concise way and the ones
I have audited so far appear to be harmless. It is not a subgroup but
rather just one warning so we do not lose out on much coverage by
default.

Link: https://github.com/ClangBuiltLinux/linux/issues/488
Link: http://releases.llvm.org/10.0.0/tools/clang/docs/DiagnosticsReference.html#wtautological-compare
Link: https://bugs.llvm.org/show_bug.cgi?id=42666
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Now that the kernel specifies binutils 2.23 as the minimum version, we
can remove ifdefs for AVX2 and ADX throughout.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

poly1305-x86_64-cryptogams.S is a generated file, so it should be
cleaned up by 'make clean'.

Assigning it to the variable 'targets' teaches Kbuild that it is a
generated file. However, this line is not evaluated when cleaning
because scripts/Makefile.clean does not include include/config/auto.conf.

Remove the ifneq-conditional, so this file is correctly cleaned up.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: Ingo Molnar <mingo@kernel.org>

The currently minimum-supported binutils version 2.21 has the problem of
promoting symbols which are defined outside of a section into absolute.
According to Arvind:

  binutils-2.21 and -2.22. An x86-64 defconfig will fail with
          Invalid absolute R_X86_64_32S relocation: _etext
  and after fixing that one, with
          Invalid absolute R_X86_64_32S relocation: __end_of_kernel_reserve

Those two versions of binutils have a bug when it comes to handling
symbols defined outside of a section and binutils 2.23 has the proper
fix, see: https://sourceware.org/legacy-ml/binutils/2012-06/msg00155.html

Therefore, up to the fixed version directly, skipping the broken ones.

Currently shipping distros already have the fixed binutils version so
there should be no breakage resulting from this.

For more details about the whole thing, see the thread in Link.

Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200110202349.1881840-1-nivedita@alum.mit.edu
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Jason A. Donenfeld <Jason@zx2c4.com>
Acked-by: Nick Desaulniers <ndesaulniers@google.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Since we're doing a static inline dispatch here, we normally branch
based on whether or not there's an arch implementation. That would have
been fine in general, except the crypto Makefile prior used to turn
things off -- despite the Kconfig -- resulting in us needing to also
hard code various assembler things into the dispatcher too. The horror!
Now that the assembler config options are done by Kconfig, we can get
rid of the inconsistency.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Now that assembler capabilities are probed inside of Kconfig, we can set
up proper Kconfig-based dependencies. We also take this opportunity to
reorder the Makefile, so that items are grouped logically by primitive.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

We raise the minimal supported binutils version from time to time.
The last bump was commit 1fb12b35

 ("kbuild: Raise the minimum
required binutils version to 2.21").

We have these as-instr tests because binutils 2.21 does not support
them.

When we bump the binutils version next time, this will be a good
hint to find out which one can be dropped.

As for the Clang/LLVM builds, we require very new LLVM version,
so the LLVM integrated assembler supports all of them.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Jason A. Donenfeld <Jason@zx2c4.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Nick Desaulniers <ndesaulniers@google.com>

Doing this probing inside of the Makefiles means we have a maze of
ifdefs inside the source code and child Makefiles that need to make
proper decisions on this too. Instead, we do it at Kconfig time, like
many other compiler and assembler options, which allows us to set up the
dependencies normally for full compilation units. In the process, the
ADX test changes to use %eax instead of %r10 so that it's valid in both
32-bit and 64-bit mode.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

CONFIG_AS_MOVNTDQA was introduced by commit 0b1de5d5 ("drm/i915:
Use SSE4.1 movntdqa to accelerate reads from WC memory").

We raise the minimal supported binutils version from time to time.
The last bump was commit 1fb12b35

 ("kbuild: Raise the minimum
required binutils version to 2.21").

I confirmed the code in $(call as-instr,...) can be assembled by the
binutils 2.21 assembler and also by LLVM integrated assembler.

Remove CONFIG_AS_MOVNTDQA, which is always defined.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Jason A. Donenfeld <Jason@zx2c4.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Jani Nikula <jani.nikula@intel.com>

CONFIG_AS_AVX was introduced by commit ea4d26ae ("raid5: add AVX
optimized RAID5 checksumming").

We raise the minimal supported binutils version from time to time.
The last bump was commit 1fb12b35

 ("kbuild: Raise the minimum
required binutils version to 2.21").

I confirmed the code in $(call as-instr,...) can be assembled by the
binutils 2.21 assembler and also by LLVM integrated assembler.

Remove CONFIG_AS_AVX, which is always defined.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Jason A. Donenfeld <Jason@zx2c4.com>
Acked-by: Ingo Molnar <mingo@kernel.org>

CONFIG_AS_SSSE3 was introduced by commit 75aaf4c3 ("x86/raid6:
correctly check for assembler capabilities").

We raise the minimal supported binutils version from time to time.
The last bump was commit 1fb12b35

 ("kbuild: Raise the minimum
required binutils version to 2.21").

I confirmed the code in $(call as-instr,...) can be assembled by the
binutils 2.21 assembler and also by LLVM integrated assembler.

Remove CONFIG_AS_SSSE3, which is always defined.

I added ifdef CONFIG_X86 to lib/raid6/algos.c to avoid link errors
on non-x86 architectures.

lib/raid6/algos.c is built not only for the kernel but also for
testing the library code from userspace. I added -DCONFIG_X86 to
lib/raid6/test/Makefile to cator to this usecase.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Jason A. Donenfeld <Jason@zx2c4.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Acked-by: Ingo Molnar <mingo@kernel.org>

CONFIG_AS_CFI_SECTIONS was introduced by commit 9e565292 ("x86:
Use .cfi_sections for assembly code").

We raise the minimal supported binutils version from time to time.
The last bump was commit 1fb12b35

 ("kbuild: Raise the minimum
required binutils version to 2.21").

I confirmed the code in $(call as-instr,...) can be assembled by the
binutils 2.21 assembler and also by LLVM integrated assembler.

Remove CONFIG_AS_CFI_SECTIONS, which is always defined.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Jason A. Donenfeld <Jason@zx2c4.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Acked-by: Ingo Molnar <mingo@kernel.org>

Commit 131484c8

 ("x86/debug: Remove perpetually broken,
unmaintainable dwarf annotations") removes all the users of
CFI_SIGNAL_FRAME.

Remove the CFI_SIGNAL_FRAME and CONFIG_AS_CFI_SIGNAL_FRAME.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Jason A. Donenfeld <Jason@zx2c4.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Acked-by: Ingo Molnar <mingo@kernel.org>

CONFIG_AS_CFI was introduced by commit e2414910 ("[PATCH] x86:
Detect CFI support in the assembler at runtime"), and extended by
commit f0f12d85 ("x86_64: Check for .cfi_rel_offset in CFI probe").

We raise the minimal supported binutils version from time to time.
The last bump was commit 1fb12b35

 ("kbuild: Raise the minimum
required binutils version to 2.21").

I confirmed the code in $(call as-instr,...) can be assembled by the
binutils 2.21 assembler and also by LLVM integrated assembler.

Remove CONFIG_AS_CFI, which is always defined.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Jason A. Donenfeld <Jason@zx2c4.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Acked-by: Ingo Molnar <mingo@kernel.org>

This header file has the following check at the top:

  #ifndef __ASSEMBLY__
  #warning "asm/dwarf2.h should be only included in pure assembly files"
  #endif

So, we expect defined(__ASSEMBLY__) is always true.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Jason A. Donenfeld <Jason@zx2c4.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Acked-by: Ingo Molnar <mingo@kernel.org>

You can build a user-space test program for the raid6 library code,
like this:

  $ cd lib/raid6/test
  $ make

The command in $(shell ...) function is evaluated by /bin/sh by default.
(or, you can specify the shell by passing SHELL=<shell> from command line)

Currently '>&/dev/null' is used to sink both stdout and stderr. Because
this code is bash-ism, it only works when /bin/sh is a symbolic link to
bash (this is the case on RHEL etc.)

This does not work on Ubuntu where /bin/sh is a symbolic link to dash.

I see lots of

  /bin/sh: 1: Syntax error: Bad fd number

and

  warning "your version of binutils lacks ... support"

Replace it with portable '>/dev/null 2>&1'.

Fixes: 4f8c55c5

 ("lib/raid6: build proper files on corresponding arch")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: H. Peter Anvin (Intel) <hpa@zytor.com>
Reviewed-by: Jason A. Donenfeld <Jason@zx2c4.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

These are listed in include/uapi/asm-generic/Kbuild, so Kbuild will
automatically generate them.

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

These types should be defined in posix_types.h, not in bitsperlong.h .

With these defines moved, h8300-specific bitsperlong.h is no longer
needed since Kbuild will automatically create a wrapper of
include/uapi/asm-generic/bitsperlong.h

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

__builtin_constant_p(nr) is used everywhere now. It does not make
much sense to define IS_IMMEDIATE() as its alias.

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

Pull drm fixes from Dave Airlie:
 "This is a set of fixes that have queued up, I think I might have
  another pull with some more before rc1 but I'd like to dequeue what I
  have now just in case Easter is more eggciting that expected.

  The main thing in here is a fix for a longstanding nouveau power
  management issues on certain laptops, it should help runtime
  suspend/resume for a lot of people.

  There is also a reverted patch for some drm_mm behaviour in atomic
  contexts.

  Summary:

  core:
   - revert drm_mm atomic patch
   - dt binding fixes

  fbcon:
   - null ptr error fix

  i915:
   - GVT fixes

  nouveau:
   - runpm fix
   - svm fixes

  amdgpu:
   - HDCP fixes
   - gfx10 fix
   - Misc display fixes
   - BACO fixes

  amdkfd:
   - Fix memory leak

  vboxvideo:
   - remove conflicting fbs

  vc4:
   - mode validation fix

  xen:
   - fix PTR_ERR usage"

* tag 'drm-next-2020-04-08' of git://anongit.freedesktop.org/drm/drm: (41 commits)
  drm/nouveau/kms/nv50-: wait for FIFO space on PIO channels
  drm/nouveau/nvif: protect waits against GPU falling off the bus
  drm/nouveau/nvif: access PTIMER through usermode class, if available
  drm/nouveau/gr/gp107,gp108: implement workaround for HW hanging during init
  drm/nouveau: workaround runpm fail by disabling PCI power management on certain intel bridges
  drm/nouveau/svm: remove useless SVM range check
  drm/nouveau/svm: check for SVM initialized before migrating
  drm/nouveau/svm: fix vma range check for migration
  drm/nouveau: remove checks for return value of debugfs functions
  drm/nouveau/ttm: evict other IO mappings when running out of BAR1 space
  drm/amdkfd: kfree the wrong pointer
  drm/amd/display: increase HDCP authentication delay
  drm/amd/display: Correctly cancel future watchdog and callback events
  drm/amd/display: Don't try hdcp1.4 when content_type is set to type1
  drm/amd/powerplay: move the ASIC specific nbio operation out of smu_v11_0.c
  drm/amd/powerplay: drop redundant BIF doorbell interrupt operations
  drm/amd/display: Fix dcn21 num_states
  drm/amd/display: Enable BT2020 in COLOR_ENCODING property
  drm/amd/display: LFC not working on 2.0x range monitors (v2)
  drm/amd/display: Support plane level CTM
  ...

Pull input updates from Dmitry Torokhov:
 "An update to the Goodix touchscreen driver to enable it work properly
  on various Bay Trail and Cherry Trail devices, and a few other
  assorted changes"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input: (26 commits)
  Input: update SPDX tag for input-event-codes.h
  Input: i8042 - add Acer Aspire 5738z to nomux list
  Input: goodix - fix compilation when ACPI support is disabled
  dt-bindings: touchscreen: Convert edt-ft5x06 to json-schema
  Input: of_touchscreen - explicitly choose axis
  Input: goodix - support gt9147 touchpanel
  dt-bindings: touchscreen: goodix: support of gt9147
  Input: goodix - add support for Goodix GT917S
  Input: goodix - use string-based chip ID
  dt-bindings: input: touchscreen: add compatible string for Goodix GT917S
  Input: goodix - add support for more then one touch-key
  Input: goodix - fix spurious key release events
  Input: goodix - try to reset the controller if the i2c-test fails
  Input: goodix - restore config on resume if necessary
  Input: goodix - make goodix_send_cfg() take a raw buffer as argument
  Input: goodix - add minimum firmware size check
  Input: goodix - save a copy of the config from goodix_read_config()
  Input: goodix - move defines to above struct goodix_ts_data declaration
  Input: goodix - add support for controlling the IRQ pin through ACPI methods
  Input: goodix - add support for getting IRQ + reset GPIOs on Bay Trail devices
  ...

Pull thermal updates from Daniel Lezcano:

 - Convert tsens configuration DT binding to yaml (Rajeshwari)

 - Add interrupt support on the rcar sensor (Niklas Söderlund)

 - Add a new Spreadtrum thermal driver (Baolin Wang)

 - Add thermal binding for the fsl scu board, a new API to retrieve the
   sensor id bound to the thermal zone and i.MX system controller sensor
   (Anson Huang))

 - Remove warning log when a deferred probe is requested on Exynos
   (Marek Szyprowski)

 - Add the thermal monitoring unit support for imx8mm with its DT
   bindings (Anson Huang)

 - Rephrase the Kconfig text for clarity (Linus Walleij)

 - Use the gpio descriptor for the ti-soc-thermal (Linus Walleij)

 - Align msg structure to 4 bytes for i.MX SC, fix the Kconfig
   dependency, add the __may_be unused annotation for PM functions and
   the COMPILE_TEST option for imx8mm (Anson Huang)

 - Fix a dependency on regmap in Kconfig for qoriq (Yuantian Tang)

 - Add DT binding and support for the rcar gen3 r8a77961 and improve the
   error path on the rcar init function (Niklas Söderlund)

 - Cleanup and improvements for the tsens Qcom sensor (Amit Kucheria)

 - Improve code by removing lock and caching values in the rcar thermal
   sensor (Niklas Söderlund)

 - Cleanup in the qoriq drivers and add a call to
   imx_thermal_unregister_legacy_cooling in the removal function (Anson
   Huang)

 - Remove redundant 'maxItems' in tsens and sprd DT bindings (Rob
   Herring)

 - Change the thermal DT bindings by making the cooling-maps optional
   (Yuantian Tang)

 - Add Tiger Lake support (Sumeet Pawnikar)

 - Use scnprintf() for avoiding potential buffer overflow (Takashi Iwai)

 - Make pkg_temp_lock a raw_spinlock_t(Clark Williams)

 - Fix incorrect data types by changing them to signed on i.MX SC (Anson
   Huang)

 - Replace zero-length array with flexible-array member (Gustavo A. R.
   Silva)

 - Add support for i.MX8MP in the driver and in the DT bindings (Anson
   Huang)

 - Fix return value of the cpufreq_set_cur_state() function (Willy
   Wolff)

 - Remove abusing and scary WARN_ON in the cpufreq cooling device
   (Daniel Lezcano)

 - Fix build warning of incorrect argument type reported by sparse on
   imx8mm (Anson Huang)

 - Fix stub for the devfreq cooling device (Martin Blumenstingl)

 - Fix cpu idle cooling documentation (Sergey Vidishev)

* tag 'thermal-v5.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thermal/linux: (52 commits)
  Documentation: cpu-idle-cooling: Fix diagram for 33% duty cycle
  thermal: devfreq_cooling: inline all stubs for CONFIG_DEVFREQ_THERMAL=n
  thermal: imx8mm: Fix build warning of incorrect argument type
  thermal/drivers/cpufreq_cooling: Remove abusing WARN_ON
  thermal/drivers/cpufreq_cooling: Fix return of cpufreq_set_cur_state
  thermal: imx8mm: Add i.MX8MP support
  dt-bindings: thermal: imx8mm-thermal: Add support for i.MX8MP
  thermal: qcom: tsens.h: Replace zero-length array with flexible-array member
  thermal: imx_sc_thermal: Fix incorrect data type
  thermal: int340x_thermal: Use scnprintf() for avoiding potential buffer overflow
  thermal: int340x: processor_thermal: Add Tiger Lake support
  thermal/x86_pkg_temp: Make pkg_temp_lock a raw_spinlock_t
  dt-bindings: thermal: make cooling-maps property optional
  dt-bindings: thermal: qcom-tsens: Remove redundant 'maxItems'
  dt-bindings: thermal: sprd: Remove redundant 'maxItems'
  thermal: imx: Calling imx_thermal_unregister_legacy_cooling() in .remove
  thermal: qoriq: Sort includes alphabetically
  thermal: qoriq: Use devm_add_action_or_reset() to handle all cleanups
  thermal: rcar_thermal: Remove lock in rcar_thermal_get_current_temp()
  thermal: rcar_thermal: Do not store ctemp in rcar_thermal_priv
  ...

Pull mfd updates from Lee Jones:
 "New Drivers:
   - Add support for IQS620A/621/622/624/625 Azoteq IQS62X Sensors

  New Device Support:
   - Add support for ADC, IRQ, Regulator, RTC and WDT to Ricoh RN5T618 PMIC
   - Add support for Comet Lake to Intel LPSS

  New Functionality:
   - Add support for Charger Detection to Spreadtrum SC27xx PMICs
   - Add support for Interrupt Polarity to Dialog Semi DA9062/61 PMIC
   - Add ACPI enumeration support to Diolan DLN2 USB Adaptor

  Fix-ups:
   - Device Tree; iqs62x, rn5t618, cros_ec_dev, stm32-lptimer, rohm,bd71837, rohm,bd71847
   - I2C registration; rn5t618
   - Kconfig; MFD_CPCAP, AB8500_CORE, MFD_WM8994, MFD_WM97xx, MFD_STPMIC1
   - Use flexible-array members; omap-usb-tll, qcom-pm8xxx
   - Remove unnecessary casts; omap-usb-host, omap-usb-tll
   - Power (suspend/resume/poweroff) enhancements; rk808
   - Improve error/sanity checking; dln2
   - Use snprintf(); aat2870-core

  Bug Fixes:
   - Fix PCI IDs in intel-lpss-pci"

* tag 'mfd-next-5.7' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/mfd: (33 commits)
  mfd: intel-lpss: Fix Intel Elkhart Lake LPSS I2C input clock
  mfd: aat2870: Use scnprintf() for avoiding potential buffer overflow
  mfd: dln2: Allow to be enumerated via ACPI
  mfd: da9062: Add support for interrupt polarity defined in device tree
  dt-bindings: bd718x7: Yamlify and add BD71850
  mfd: dln2: Fix sanity checking for endpoints
  mfd: intel-lpss: Add Intel Comet Lake PCH-V PCI IDs
  mfd: sc27xx: Add USB charger type detection support
  dt-bindings: mfd: Document STM32 low power timer bindings
  mfd: rk808: Convert RK805 to shutdown/suspend hooks
  mfd: rk808: Reduce shutdown duplication
  mfd: rk808: Stop using syscore ops
  mfd: rk808: Ensure suspend/resume hooks always work
  mfd: rk808: Always use poweroff when requested
  mfd: omap: Remove useless cast for driver.name
  mfd: Kconfig: Fix some misspelling of the word functionality
  mfd: pm8xxx: Replace zero-length array with flexible-array member
  mfd: omap-usb-tll: Replace zero-length array with flexible-array member
  mfd: cpcap: Fix compile if MFD_CORE is not selected
  mfd: cros_ec: Check DT node for usbpd-notify add
  ...