CFLAGS_REMOVE_<file>.o filters out flags when compiling a particular
object, but there is no convenient way to do that for every object in
a directory.

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

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

The add/remove order works as follows:

 [1] KBUILD_CFLAGS specifies compiler flags used globally

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

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

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

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

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

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

The same applies to lib/livepatch/Makefile.

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

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

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

However, lib/ has several sub-directories.

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

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

I think commit 2464a609ded0 ("ftrace: do not trace library functions")
excluded too much. In the next commit, I will remove ccflags-remove-y
from the sub-directories of lib/.

Suggested-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Acked-by: Brendan Higgins <brendanhiggins@google.com> (KUnit)
Tested-by: Anders Roxell <anders.roxell@linaro.org>

sh5 never became a product and has probably never really worked.

Remove it by recursively deleting all associated Kconfig options
and all corresponding files.

Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Rich Felker <dalias@libc.org>

Since the patch [1], building the kernel using a toolchain built with
Binutils 2.33.1 prevent booting a sh4 system under Qemu.
Apply the patch provided by Alan Modra [2] that fix alignment of rodata.

[1] https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=ebd2263ba9a9124d93bbc0ece63d7e0fae89b40e
[2] https://www.sourceware.org/ml/binutils/2019-12/msg00112.html

Signed-off-by: Romain Naour <romain.naour@gmail.com>
Cc: Alan Modra <amodra@gmail.com>
Signed-off-by: Rich Felker <dalias@libc.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>

The C compiler is allowing more checks to make sure that function pointers
are assigned to the correct prototype function. Unfortunately, the function
graph tracer uses a special name with its assigned ftrace_graph_return
function pointer that maps to a stub function used by the function tracer
(ftrace_stub). The ftrace_graph_return variable is compared to the
ftrace_stub in some archs to know if the function graph tracer is enabled or
not. This means we can not just simply create a new function stub that
compares it without modifying all the archs.

Instead, have the linker script create a function_graph_stub that maps to
ftrace_stub, and this way we can define the prototype for it to match the
prototype of ftrace_graph_return, and make the compiler checks all happy!

Link: http://lkml.kernel.org/r/20191015090055.789a0aed@gandalf.local.home

Cc: linux-sh@vger.kernel.org
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc:  Rich Felker <dalias@libc.org>
Reported-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Add SPDX license identifiers to all Make/Kconfig files which:

 - Have no license information of any form

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

  GPL-2.0-only

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

arch/sh/boot/.gitignore has the pattern "vmlinux*"; this is effective
not only for the current directory, but also for any sub-directories.

So, from the point of .gitignore grammar, the following check-in files
are also considered to be ignored:

  arch/sh/boot/compressed/vmlinux.scr
  arch/sh/boot/romimage/vmlinux.scr

As the manual gitignore(5) says "Files already tracked by Git are not
affected", this is not a problem as far as Git is concerned.

However, Git is not the only program that parses .gitignore because
.gitignore is useful to distinguish build artifacts from source files.

For example, tar(1) supports the --exclude-vcs-ignore option. As of
writing, this option does not work perfectly, but it intends to create
a tarball excluding files specified by .gitignore.

So, I believe it is better to fix this issue.

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

I fixed a similar build error in commit 1b1e4ee86e00 ("sh: fix build
error for empty CONFIG_BUILTIN_DTB_SOURCE"), but it came back again.

Since commit 37c8a5fafa3b ("kbuild: consolidate Devicetree dtb
build rules"), the combination of CONFIG_OF_EARLY_FLATTREE=y and
CONFIG_USE_BUILTIN_DTB=n results in the following build error:

  make[1]: *** No rule to make target 'arch/sh/boot/dts/.dtb.o',
  needed by 'arch/sh/boot/dts/built-in.a'.  Stop.

Prior to that commit, there was only one path to descend into
arch/sh/boot/dts/, and arch/sh/Makefile correctly guards it with
CONFIG_USE_BUILTIN_DTB:

  core-$(CONFIG_USE_BUILTIN_DTB)  += arch/sh/boot/dts/

Now, there is another path to descend there from the top Makefile
when CONFIG_OF_EARLY_FLATTREE=y. If CONFIG_USE_BUILTIN_DTB is disabled,
CONFIG_BUILTIN_DTB_SOURCE is invisible instead of defined as "".

Add obj-$(CONFIG_USE_BUILTIN_DTB) guard to avoid the attempt to build
the non-existing file.

Fixes: 37c8a5fafa3b ("kbuild: consolidate Devicetree dtb build rules")
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

Calling __stack_chk_guard_setup() in decompress_kernel() is too late
that stack checking always fails for decompress_kernel() itself.  So
remove __stack_chk_guard_setup() and initialize __stack_chk_guard before
we call decompress_kernel().

Original code comes from ARM but also used for MIPS and SH, so fix them
together.  If without this fix, compressed booting of these archs will
fail because stack checking is enabled by default (>=4.16).

Link: http://lkml.kernel.org/r/1522226933-29317-1-git-send-email-chenhc@lemote.com
Fixes: 8779657d29c0 ("stackprotector: Introduce CONFIG_CC_STACKPROTECTOR_STRONG")
Signed-off-by: Huacai Chen <chenhc@lemote.com>
Acked-by: James Hogan <jhogan@kernel.org>
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Rich Felker <dalias@libc.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

If CONFIG_USE_BUILTIN_DTB is enabled, but CONFIG_BUILTIN_DTB_SOURCE
is empty (for example, allmodconfig), it fails to build, like this:

  make[2]: *** No rule to make target 'arch/sh/boot/dts/.dtb.o',
  needed by 'arch/sh/boot/dts/built-in.o'.  Stop.

Surround obj-y with ifneq ... endif.

I replaced $(CONFIG_USE_BUILTIN_DTB) with 'y' since this is always
the case from the following code from arch/sh/Makefile:

  core-$(CONFIG_USE_BUILTIN_DTB)  += arch/sh/boot/dts/

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