When using plugins, GCC requires that the -fplugin= options precedes
any of its plugin arguments appearing on the command line as well.
This is usually not a concern, but as it turns out, this requirement
is causing some issues with ARM's per-task stack protector plugin
and Kbuild's implementation of $(cc-option).

When the per-task stack protector plugin is enabled, and we tweak
the implementation of cc-option not to pipe the stderr output of
GCC to /dev/null, the following output is generated when GCC is
executed in the context of cc-option:

  cc1: error: plugin arm_ssp_per_task_plugin should be specified before \
         -fplugin-arg-arm_ssp_per_task_plugin-tso=1 in the command line
  cc1: error: plugin arm_ssp_per_task_plugin should be specified before \
         -fplugin-arg-arm_ssp_per_task_plugin-offset=24 in the command line

These errors will cause any option passed to cc-option to be treated
as unsupported, which is obviously incorrect.

The cause of this issue is the fact that the -fplugin= argument is
added to GCC_PLUGINS_CFLAGS, whereas the arguments above are added
to KBUILD_CFLAGS, and the contents of the former get filtered out of
the latter before being passed to the GCC running the cc-option test,
and so the -fplugin= option does not appear at all on the GCC command
line.

Adding the arguments to GCC_PLUGINS_CFLAGS instead of KBUILD_CFLAGS
would be the correct approach here, if it weren't for the fact that we
are using $(eval) to defer the moment that they are added until after
asm-offsets.h is generated, which is after the point where the contents
of GCC_PLUGINS_CFLAGS are added to KBUILD_CFLAGS. So instead, we have
to add our plugin arguments to both.

For similar reasons, we cannot append DISABLE_ARM_SSP_PER_TASK_PLUGIN
to KBUILD_CFLAGS, as it will be passed to GCC when executing in the
context of cc-option, whereas the other plugin arguments will have
been filtered out, resulting in a similar error and false negative
result as above. So add it to ccflags-y instead.

Fixes: 189af4657186da08 ("ARM: smp: add support for per-task stack canaries")
Reported-by: Merlijn Wajer <merlijn@wizzup.org>
Tested-by: Tony Lindgren <tony@atomide.com>
Acked-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>

Pull ARM updates from Russell King:

 - fix various clang build and cppcheck issues

 - switch ARM to use new common outgoing-CPU-notification code

 - add some additional explanation about the boot code

 - kbuild "make clean" fixes

 - get rid of another "(____ptrval____)", this time for the VDSO code

 - avoid treating cache maintenance faults as a write

 - add a frame pointer unwinder implementation for clang

 - add EDAC support for Aurora L2 cache

 - improve robustness of adjust_lowmem_bounds() finding the bounds of
   lowmem.

 - add reset control for AMBA primecell devices

* tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm: (24 commits)
  ARM: 8906/1: drivers/amba: add reset control to amba bus probe
  ARM: 8905/1: Emit __gnu_mcount_nc when using Clang 10.0.0 or newer
  ARM: 8904/1: skip nomap memblocks while finding the lowmem/highmem boundary
  ARM: 8903/1: ensure that usable memory in bank 0 starts from a PMD-aligned address
  ARM: 8891/1: EDAC: armada_xp: Add support for more SoCs
  ARM: 8888/1: EDAC: Add driver for the Marvell Armada XP SDRAM and L2 cache ECC
  ARM: 8892/1: EDAC: Add missing debugfs_create_x32 wrapper
  ARM: 8890/1: l2x0: add marvell,ecc-enable property for aurora
  ARM: 8889/1: dt-bindings: document marvell,ecc-enable binding
  ARM: 8886/1: l2x0: support parity-enable/disable on aurora
  ARM: 8885/1: aurora-l2: add defines for parity and ECC registers
  ARM: 8887/1: aurora-l2: add prefix to MAX_RANGE_SIZE
  ARM: 8902/1: l2c: move cache-aurora-l2.h to asm/hardware
  ARM: 8900/1: UNWINDER_FRAME_POINTER implementation for Clang
  ARM: 8898/1: mm: Don't treat faults reported from cache maintenance as writes
  ARM: 8896/1: VDSO: Don't leak kernel addresses
  ARM: 8895/1: visit mach-* and plat-* directories when cleaning
  ARM: 8894/1: boot: Replace open-coded nop with macro
  ARM: 8893/1: boot: Explain the 8 nops
  ARM: 8876/1: fix O= building with CONFIG_FPE_FASTFPE
  ...

Pull Kbuild updates from Masahiro Yamada:

 - add modpost warn exported symbols marked as 'static' because 'static'
   and EXPORT_SYMBOL is an odd combination

 - break the build early if gold linker is used

 - optimize the Bison rule to produce .c and .h files by a single
   pattern rule

 - handle PREEMPT_RT in the module vermagic and UTS_VERSION

 - warn CONFIG options leaked to the user-space except existing ones

 - make single targets work properly

 - rebuild modules when module linker scripts are updated

 - split the module final link stage into scripts/Makefile.modfinal

 - fix the missed error code in merge_config.sh

 - improve the error message displayed on the attempt of the O= build in
   unclean source tree

 - remove 'clean-dirs' syntax

 - disable -Wimplicit-fallthrough warning for Clang

 - add CONFIG_CC_OPTIMIZE_FOR_SIZE_O3 for ARC

 - remove ARCH_{CPP,A,C}FLAGS variables

 - add $(BASH) to run bash scripts

 - change *CFLAGS_<basetarget>.o to take the relative path to $(obj)
   instead of the basename

 - stop suppressing Clang's -Wunused-function warnings when W=1

 - fix linux/export.h to avoid genksyms calculating CRC of trimmed
   exported symbols

 - misc cleanups

* tag 'kbuild-v5.4' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (63 commits)
  genksyms: convert to SPDX License Identifier for lex.l and parse.y
  modpost: use __section in the output to *.mod.c
  modpost: use MODULE_INFO() for __module_depends
  export.h, genksyms: do not make genksyms calculate CRC of trimmed symbols
  export.h: remove defined(__KERNEL__), which is no longer needed
  kbuild: allow Clang to find unused static inline functions for W=1 build
  kbuild: rename KBUILD_ENABLE_EXTRA_GCC_CHECKS to KBUILD_EXTRA_WARN
  kbuild: refactor scripts/Makefile.extrawarn
  merge_config.sh: ignore unwanted grep errors
  kbuild: change *FLAGS_<basetarget>.o to take the path relative to $(obj)
  modpost: add NOFAIL to strndup
  modpost: add guid_t type definition
  kbuild: add $(BASH) to run scripts with bash-extension
  kbuild: remove ARCH_{CPP,A,C}FLAGS
  kbuild,arc: add CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3 for ARC
  kbuild: Do not enable -Wimplicit-fallthrough for clang for now
  kbuild: clean up subdir-ymn calculation in Makefile.clean
  kbuild: remove unneeded '+' marker from cmd_clean
  kbuild: remove clean-dirs syntax
  kbuild: check clean srctree even earlier
  ...

Currently, multi_v7_defconfig + CONFIG_FUNCTION_TRACER fails to build
with clang:

arm-linux-gnueabi-ld: kernel/softirq.o: in function `_local_bh_enable':
softirq.c:(.text+0x504): undefined reference to `mcount'
arm-linux-gnueabi-ld: kernel/softirq.o: in function `__local_bh_enable_ip':
softirq.c:(.text+0x58c): undefined reference to `mcount'
arm-linux-gnueabi-ld: kernel/softirq.o: in function `do_softirq':
softirq.c:(.text+0x6c8): undefined reference to `mcount'
arm-linux-gnueabi-ld: kernel/softirq.o: in function `irq_enter':
softirq.c:(.text+0x75c): undefined reference to `mcount'
arm-linux-gnueabi-ld: kernel/softirq.o: in function `irq_exit':
softirq.c:(.text+0x840): undefined reference to `mcount'
arm-linux-gnueabi-ld: kernel/softirq.o:softirq.c:(.text+0xa50): more undefined references to `mcount' follow

clang can emit a working mcount symbol, __gnu_mcount_nc, when
'-meabi gnu' is passed to it. Until r369147 in LLVM, this was
broken and caused the kernel not to boot with '-pg' because the
calling convention was not correct. Always build with '-meabi gnu'
when using clang but ensure that '-pg' (which is added with
CONFIG_FUNCTION_TRACER and its prereq CONFIG_HAVE_FUNCTION_TRACER)
cannot be added with it unless this is fixed (which means using
clang 10.0.0 and newer).

Link: https://github.com/ClangBuiltLinux/linux/issues/35
Link: https://bugs.llvm.org/show_bug.cgi?id=33845
Link: https://github.com/llvm/llvm-project/commit/16fa8b09702378bacfa3d07081afe6b353b99e60

Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>

ASPEED architecture updates for 5.4

This adds support for the new ASPEED AST2600 BMC SoC.

* tag 'aspeed-5.4-arch' of git://git.kernel.org/pub/scm/linux/kernel/git/joel/aspeed:
  ARM: aspeed: Enable SMP boot
  ARM: aspeed: Add ASPEED AST2600 architecture
  ARM: aspeed: Select timer in each SoC
  dt-bindings: arm: cpus: Add ASPEED SMP

Link: https://lore.kernel.org/r/CACPK8Xc1aSp5fXL3cEzC9SJsCXG2JwsSPpQrW3a09dkvhCyHHA@mail.gmail.com
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

The stackframe setup when compiled with clang is different.
Since the stack unwinder expects the gcc stackframe setup it
fails to print backtraces. This patch adds support for the
clang stackframe setup.

Link: https://github.com/ClangBuiltLinux/linux/issues/35

Cc: clang-built-linux@googlegroups.com
Suggested-by: Tri Vo <trong@google.com>
Signed-off-by: Nathan Huckleberry <nhuck@google.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>

This brings the secondary CPU into Linux. It depends on the setup
performed by ASPEED's u-boot.

Signed-off-by: Joel Stanley <joel@jms.id.au>

When you run "make clean" for arm, it never visits mach-* or plat-*
directories because machine-y and plat-y are just empty.

When cleaning, all machine, plat directories are accumulated to
machine-, plat-, respectively. So, let's pass them to core- to
clean up those directories.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>

To use Fastfpe, a user is supposed to enable CONFIG_FPE_FASTFPE
and put downstream source files into arch/arm/fastfpe/.

It is not working for O= build because $(wildcard arch/arm/fastfpe)
checks if it exists in $(objtree), not in $(srctree).

Add the $(srctree)/ prefix to fix it.

While I was here, I slightly refactored the code.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>

Currently, the timestamp of module linker scripts are not checked.
Add them to the dependency of modules so they are correctly rebuilt.

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