There's not much sense in doing that because if user or
his build-system didn't set CROSS_COMPILE we still may
very well make incorrect guess.

But as it turned out setting CROSS_COMPILE is not as harmless
as one may think: with recent changes that implemented automatic
discovery of __host__ gcc features unconditional setup of
CROSS_COMPILE leads to failures on execution of "make xxx_defconfig"
with absent cross-compiler, for more info see [1].

Set CROSS_COMPILE as well gets in the way if we want only to build
.dtb's (again with absent cross-compiler which is not really needed
for building .dtb's), see [2].

Note, we had to change LIBGCC assignment type from ":=" to "="
so that is is resolved on its usage, otherwise if it is resolved
at declaration time with missing CROSS_COMPILE we're getting this
error message from host GCC:

| gcc: error: unrecognized command line option -mmedium-calls
| gcc: error: unrecognized command line option -mno-sdata

[1] http://lists.infradead.org/pipermail/linux-snps-arc/2018-September/004308.html
[2] http://lists.infradead.org/pipermail/linux-snps-arc/2018-September/004320.htmlSigned-off-by: NAlexey Brodkin <abrodkin@synopsys.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Rob Herring <robh@kernel.org>
Signed-off-by: NVineet Gupta <vgupta@synopsys.com>

This check is very naive: we simply test if GCC invoked without
"-mcpu=XXX" has ARC700 define set. In that case we think that GCC
was built with "--with-cpu=arc700" and has libgcc built for ARC700.

Otherwise if ARC700 is not defined we think that everythng was built
for ARCv2.

But in reality our life is much more interesting.

1. Regardless of GCC configuration (i.e. what we pass in "--with-cpu"
   it may generate code for any ARC core).

2. libgcc might be built with explicitly specified "--mcpu=YYY"

That's exactly what happens in case of multilibbed toolchains:
 - GCC is configured with default settings
 - All the libs built for many different CPU flavors

I.e. that check gets in the way of usage of multilibbed
toolchains. And even non-multilibbed toolchains are affected.
OpenEmbedded also builds GCC without "--with-cpu" because
each and every target component later is compiled with explicitly
set "-mcpu=ZZZ".
Acked-by: NRob Herring <robh@kernel.org>
Signed-off-by: NAlexey Brodkin <abrodkin@synopsys.com>
Signed-off-by: NVineet Gupta <vgupta@synopsys.com>

helps gcc with better instruction selections such as 64-bit multiply MPYD

before
------
82c34b58 <sched_clock>:
82c34b58:	ld	r2,[0x83068d00]
82c34b60:	add_s	r2,r2,0x7530
82c34b66:	mov_s	r0,0x989680
82c34b6c:	mpymu	r5,r2,r0
82c34b70:	mpy	r4,r2,r0
82c34b74:	mov_s	r0,r4
82c34b76:	j_s.d	[blink]
82c34b78:	mov_s	r1,r5
82c34b7a:	nop_s

after
------
82c34b7c <sched_clock>:
82c34b7c:	ld	r0,[0x83064d00]
82c34b84:	add_s	r0,r0,0x7530
82c34b8a:	mpydu	r0,r0,0x989680
82c34b92:	j_s	[blink]
Signed-off-by: NVineet Gupta <vgupta@synopsys.com>

Commit cafa0010 ("Raise the minimum required gcc version to 4.6")
bumped the minimum GCC version to 4.6 for all architectures.

With GCC >= 4.6 assumed, 'upto_gcc44' is empty, 'atleast_gcc44' is y.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: NVineet Gupta <vgupta@synopsys.com>

Commit a0f97e06 ("kbuild: enable 'make CFLAGS=...' to add
additional options to CC") renamed CFLAGS to KBUILD_CFLAGS.

Commit 222d394d ("kbuild: enable 'make AFLAGS=...' to add
additional options to AS") renamed AFLAGS to KBUILD_AFLAGS.

Commit 06c5040c ("kbuild: enable 'make CPPFLAGS=...' to add
additional options to CPP") renamed CPPFLAGS to KBUILD_CPPFLAGS.

For some reason, LDFLAGS was not renamed.

Using a well-known variable like LDFLAGS may result in accidental
override of the variable.

Kbuild generally uses KBUILD_ prefixed variables for the internally
appended options, so here is one more conversion to sanitize the
naming convention.

I did not touch Makefiles under tools/ since the tools build system
is a different world.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: NPalmer Dabbelt <palmer@sifive.com>

GCC built for arc*-*-linux has "-mmedium-calls" implicitly enabled by default
thus we don't see any problems during Linux kernel compilation.
----------------------------->8------------------------
arc-linux-gcc -mcpu=arc700 -Q --help=target | grep calls
  -mlong-calls                          [disabled]
  -mmedium-calls                        [enabled]
----------------------------->8------------------------

But if we try to use so-called Elf32 toolchain with GCC configured for
arc*-*-elf* then we'd see the following failure:
----------------------------->8------------------------
init/do_mounts.o: In function 'init_rootfs':
do_mounts.c:(.init.text+0x108): relocation truncated to fit: R_ARC_S21W_PCREL
against symbol 'unregister_filesystem' defined in .text section in fs/filesystems.o

arc-elf32-ld: final link failed: Symbol needs debug section which does not exist
make: *** [vmlinux] Error 1
----------------------------->8------------------------

That happens because neither "-mmedium-calls" nor "-mlong-calls" are enabled in
Elf32 GCC:
----------------------------->8------------------------
arc-elf32-gcc -mcpu=arc700 -Q --help=target | grep calls
  -mlong-calls                          [disabled]
  -mmedium-calls                        [disabled]
----------------------------->8------------------------

Now to make it possible to use Elf32 toolchain for building Linux kernel
we're explicitly add "-mmedium-calls" to CFLAGS.

And since we add "-mmedium-calls" to the global CFLAGS there's no point in
having per-file copies thus removing them.
Signed-off-by: NAlexey Brodkin <abrodkin@synopsys.com>
Signed-off-by: NVineet Gupta <vgupta@synopsys.com>

The top-level Makefile sets the default of UTS_MACHINE to $(ARCH).

If ARCH and UTS_MACHINE match, arch/$(ARCH)/Makefile need not specify
UTS_MACHINE explicitly.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: NVineet Gupta <vgupta@synopsys.com>

This initial port adds support of ARC HS Development Kit board with some
basic features such serial port, USB, SD/MMC and Ethernet.

Essentially we run Linux kernel on all 4 cores (i.e. utilize SMP) and
heavily use IO Coherency for speeding-up DMA-aware peripherals.

Note as opposed to other ARC boards we link Linux kernel to
0x9000_0000 intentionally because cores 1 and 3 configured with DCCM
situated at our more usual link base 0x8000_0000. We still can use
memory region starting at 0x8000_0000 as we reallocate DCCM in our
platform code.

Note that PAE remapping for DMA clients does not work due to an RTL bug,
so CREG_PAE register must be programmed to all zeroes, otherwise it will
cause problems with DMA to/from peripherals even if PAE40 is not used.
Acked-by: NRob Herring <robh@kernel.org>
Signed-off-by: NAlexey Brodkin <abrodkin@synopsys.com>
Signed-off-by: NEugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Signed-off-by: NVineet Gupta <vgupta@synopsys.com>

Essentially remove CONFIG_ARC_PLAT_SIM

There is no need for any platform specific code, just the board DTS
match strings which we can include unconditionally
Signed-off-by: NVineet Gupta <vgupta@synopsys.com>

The KBUILD_IMAGE variable is used by the rpm and deb-pkg targets, which
expect it to point to the image file in the build directory. The
builddeb script has a workaround for architectures which only provide
the basename, but let's provide a clean interface for packaging tools.

Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: linux-snps-arc@lists.infradead.org
Signed-off-by: NMichal Marek <mmarek@suse.com>
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>

Traditionally, we have always had warnings about uninitialized variables
enabled, as this is part of -Wall, and generally a good idea [1], but it
also always produced false positives, mainly because this is a variation
of the halting problem and provably impossible to get right in all cases
[2].

Various people have identified cases that are particularly bad for false
positives, and in commit e74fc973 ("Turn off -Wmaybe-uninitialized
when building with -Os"), I turned off the warning for any build that
was done with CC_OPTIMIZE_FOR_SIZE.  This drastically reduced the number
of false positive warnings in the default build but unfortunately had
the side effect of turning the warning off completely in 'allmodconfig'
builds, which in turn led to a lot of warnings (both actual bugs, and
remaining false positives) to go in unnoticed.

With commit 877417e6 ("Kbuild: change CC_OPTIMIZE_FOR_SIZE
definition") enabled the warning again for allmodconfig builds in v4.7
and in v4.8-rc1, I had finally managed to address all warnings I get in
an ARM allmodconfig build and most other maybe-uninitialized warnings
for ARM randconfig builds.

However, commit 6e8d666e ("Disable "maybe-uninitialized" warning
globally") was merged at the same time and disabled it completely for
all configurations, because of false-positive warnings on x86 that I had
not addressed until then.  This caused a lot of actual bugs to get
merged into mainline, and I sent several dozen patches for these during
the v4.9 development cycle.  Most of these are actual bugs, some are for
correct code that is safe because it is only called under external
constraints that make it impossible to run into the case that gcc sees,
and in a few cases gcc is just stupid and finds something that can
obviously never happen.

I have now done a few thousand randconfig builds on x86 and collected
all patches that I needed to address every single warning I got (I can
provide the combined patch for the other warnings if anyone is
interested), so I hope we can get the warning back and let people catch
the actual bugs earlier.

This reverts the change to disable the warning completely and for now
brings it back at the "make W=1" level, so we can get it merged into
mainline without introducing false positives.  A follow-up patch enables
it on all levels unless some configuration option turns it off because
of false-positives.

Link: https://rusty.ozlabs.org/?p=232 [1]
Link: https://gcc.gnu.org/wiki/Better_Uninitialized_Warnings [2]
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This has caused a bunch of build failures at a few sites, with GNU
2015.12 and older as the assembler seems to need -mlock to be able to
grok llock/scond instructions for ARC700 builds.
different places since the
older tools still seem to release
of tools which most people are using seem to trip with the -mlock flag
not being passed.

This reverts commit c3005475.

These are really ancient toggles and tools no longer require them to be
passed. This paves way for deprecating them in long run.
Signed-off-by: NVineet Gupta <vgupta@synopsys.com>

1. detect whether binutils supports the cfi pseudo ops
2. define conditional macros to generate the ops
3. define new ENTRY_CFI/END_CFI to annotate hand asm code.
   - Needed because we don't want to emit dwarf info in general ENTRY/END
     used by lowest level trap/exception/interrutp handlers as unwinder
     gets confused trying to unwind out of them. We want unwinder to
     instead stop when it hits onfo those routines
   - These provide minimal start/end cfi ops assuming routine doesn't
     touch stack memory/regs
Signed-off-by: NVineet Gupta <vgupta@synopsys.com>

In .debug_frame based unwinding regime, we used to force -gdwarf-2 since
kernel unwinder only claimed to handle dwarf 2. This changed since commit
6d0d5060 ("ARC: dw2 unwind: Don't bail for CIE.version != 1")
which added some support beyond dwarf 2, atleast to handle CIE != 1

The ill-effect of -gdwarf-2 is that it forces generation of .debug_*
sections, which bloats loadable modules .ko files. For the curious, this
doesn't affect vmlinx binary since linker script discards .debug_* but
same discard is not yet implemented for modules.

So it seems we can drop the -gdwarf-2 toggle, which should not be needed
anyways given that we now use .eh_frame based unwinding.

I've verified using GNU 2016.09-engo10 that the actual unwind info is
not different with or w/o this toggle - but the debug_* sections are
gone for good.

before
-----
arc-linux-readelf -S q_proc.ko-unwinding-1-eh_frame-switch | grep debug
  [15] .debug_info       PROGBITS        00000000 000300 00d08d 00 	0   0  1
  [16] .rela.debug_info  RELA            00000000 0162a0 008844 0c   I 29  15  4
  [17] .debug_abbrev     PROGBITS        00000000 00d38d 0005f8 00 	0   0  1
  [18] .debug_loc        PROGBITS        00000000 00d985 000070 00 	0   0  1
  [19] .rela.debug_loc   RELA            00000000 01eae4 0000c0 0c   I 29  18  4
  [20] .debug_aranges    PROGBITS        00000000 00d9f5 000040 00 	0   0  1
  [21] .rela.debug_arang RELA            00000000 01eba4 000030 0c   I 29  20  4
  [22] .debug_ranges     PROGBITS        00000000 00da35 000018 00 	0   0  1
  [23] .rela.debug_range RELA            00000000 01ebd4 000030 0c   I 29  22  4
  [24] .debug_line       PROGBITS        00000000 00da4d 000b5b 00 	0   0  1
  [25] .rela.debug_line  RELA            00000000 01ec04 0000cc 0c   I 29  24  4
  [26] .debug_str        PROGBITS        00000000 00e5a8 007831 01   MS 0   0  1

after
----
Signed-off-by: NVineet Gupta <vgupta@synopsys.com>

So finally after almost 8 years of dealing with .debug_frame, we are
finally switching to .eh_frame. The reason being stripped kernel
binaries had non-functional unwinder as .debug_frame was gone.
Also, in general .eh_frame seems more common way of doing unwinding.

This also folds a revert of f52e126c ("ARC: unwind: ensure that
.debug_frame is generated (vs. .eh_frame)") to ensure that we start
getting .eh_frame
Reported-by: NDaniel Mentz <danielmentz@google.com>
Signed-off-by: NVineet Gupta <vgupta@synopsys.com>

Several build configurations had already disabled this warning because
it generates a lot of false positives.  But some had not, and it was
still enabled for "allmodconfig" builds, for example.

Looking at the warnings produced, every single one I looked at was a
false positive, and the warnings are frequent enough (and big enough)
that they can easily hide real problems that you don't notice in the
noise generated by -Wmaybe-uninitialized.

The warning is good in theory, but this is a classic case of a warning
that causes more problems than the warning can solve.

If gcc gets better at avoiding false positives, we may be able to
re-enable this warning.  But as is, we're better off without it, and I
want to be able to see the *real* warnings.
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

With recent binutils update to support dwarf CFI pseudo-ops in gas, we
now get .eh_frame vs. .debug_frame. Although the call frame info is
exactly the same in both, the CIE differs, which the current kernel
unwinder can't cope with.

This broke both the kernel unwinder as well as loadable modules (latter
because of a new unhandled relo R_ARC_32_PCREL from .rela.eh_frame in
the module loader)

The ideal solution would be to switch unwinder to .eh_frame.
For now however we can make do by just ensureing .debug_frame is
generated by removing -fasynchronous-unwind-tables

 .eh_frame    generated with -gdwarf-2 -fasynchronous-unwind-tables
 .debug_frame generated with -gdwarf-2

Fixes STAR 9001058196

Cc: stable@vger.kernel.org
Signed-off-by: NVineet Gupta <vgupta@synopsys.com>

Signed-off-by: NAndrea Gelmini <andrea.gelmini@gelma.net>
Signed-off-by: NVineet Gupta <vgupta@synopsys.com>

This commit should be left last since only now eznps platform
is in state which one can actually use.
Signed-off-by: NNoam Camus <noamc@ezchip.com>

linux-next has been reporting gazillion warnings for ARC build and
I finally decided to take a bite:

http://kisskb.ellerman.id.au/kisskb/buildresult/12638735/

Most of the them are due to -Wmaybe-uninitialized

| ../kernel/sysctl.c: In function '__do_proc_doulongvec_minmax':
| ../kernel/sysctl.c:1928:12: warning: 'p' may be used uninitialized in this function [-Wmaybe-uninitialized]
|   ret = tmp - *buf;
|            ^
| ../kernel/sysctl.c:2342:29: note: 'p' was declared here
|  char *kbuf = NULL, *p;
|                     ^
| ...
| ...

Cursory look at code seemed fine and a definite gcc false positive in say
kernel/sysctl.c

Mystery was why only for ARC (and not with ARM linaro toolchain based
off same gcc 4.8). Turns out that -O3 (default for ARC) triggers these
and if I enable -O3 for ARM kernel build, I see the same splat.

I initially wanted to disable this only for gcc 4.8, but Arnd reported
it is seen even on gcc 6.0 for ARM with -O3. Thus better to disable
this independent of gcc version.

Cc: Claudiu Zissulescu <Claudiu.Zissulescu@synopsys.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: linux-kbuild@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NVineet Gupta <vgupta@synopsys.com>

ARC architecture has 2 instruction sets: ARCompact/ARCv2.
While same gcc supports compiling for either (using appropriate toggles),
we can't use the same toolchain to build kernel because libgcc needs
to be unique and the toolchian (uClibc based) is not multilibed.

uClibc toolchain is convenient since it allows all userspace and
kernel to be built with a single install for an ISA.

This however means 2 gnu installs (with same triplet prefix) are needed
for building for 2 ISA and need to be in PATH.
As developers we keep switching the builds, but would occassionally fail
to update the PATH leading to usage of wrong tools. And this would only
show up at the end of kernel build when linking incompatible libgcc.

So the initial solution was to have gcc define a special preprocessor macro
DEFAULT_CPU_xxx which is unique for default toolchain configuration.
Claudiu proposed using grep for an existing preprocessor macro which is
again uniquely defined per ISA.

Cc: Michal Marek <mmarek@suse.cz>
Suggested-by: NClaudiu Zissulescu <claziss@synopsys.com>
Signed-off-by: NVineet Gupta <vgupta@synopsys.com>

This allows CONFIG_CPU_BIG_ENDIAN=y to build correctly out of the box,
w/o any other tweaks.

Cc: Noam Camus <noamc@ezchip.com>
Cc: Alexey Brodkin <abrodkin@synopsys.com>
Cc: Anton Kolesov <akolesov@synosys.com>
Signed-off-by: NVineet Gupta <vgupta@synopsys.com>

It is unlikely that designs running Linux will not have multiplier.
Further the current support is not complete as tool don't generate a
multilib w/o multiplier.
Signed-off-by: NVineet Gupta <vgupta@synopsys.com>

At -Os, ARC gcc generates millicode thunk for function prologue/epilogue,
which are served by libgcc.

Modules historically are NOT linked with libgcc to avoid code bloat, reducing
runtime relocation fixups etc. I even once tried doing that but got lost
in makefile intricacies.

This means modules at -Os don't get the millicode thunks, causing build
failures below:

| MODPOST 5 modules
| ERROR: "__ld_r13_to_r18" [crypto/sha256_generic.ko] undefined!
| ERROR: "__ld_r13_to_r18_ret" [crypto/sha256_generic.ko] undefined!
| ERROR: "__st_r13_to_r18" [crypto/sha256_generic.ko] undefined!
| ERROR: "__ld_r13_to_r17_ret" [crypto/sha256_generic.ko] undefined!
| ERROR: "__st_r13_to_r17" [crypto/sha256_generic.ko] undefined!
| ERROR: "__ld_r13_to_r16_ret" [crypto/sha256_generic.ko] undefined!
| ERROR: "__st_r13_to_r16" [crypto/sha256_generic.ko] undefined!
|....
|....

Workaround that by inhibiting millicode thunks for loadable modules

Fixes STAR 9000641864:
("Linux built with optimizations for size emits errors for modules")
Reported-by: NAnton Kolesov <akolesov@synosys.com>
Cc: Michal Marek <mmarek@suse.cz>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NVineet Gupta <vgupta@synopsys.com>

Use dtb-y and always make variables to build dtbs instead of explicit
dtbs rule. This is in preparation to support building all dtbs.
Signed-off-by: NRob Herring <robh@kernel.org>
Acked-by: NVineet Gupta <vgupta@synopsys.com>

Being highly configurable core ARC HS among other features might be
configured with or without DIV_REM_OPTION (hardware divider).

That option when enabled adds following instructions: div, divu, rem, remu.

By default ARC HS38 has this option enabled. So we add here possibility
to disable usage of hardware divider by compiler.
Signed-off-by: NAlexey Brodkin <abrodkin@synopsys.com>
Signed-off-by: NVineet Gupta <vgupta@synopsys.com>

ARC kernels have historically been built with -O3, despite top level
Makefile defaulting to -O2. This was facilitated by implicitly ordering
of arch makefile include AFTER top level assigned -O2.

An upstream fix to top level a1c48bb1 ("Makefile: Fix unrecognized
cross-compiler command line options") changed the ordering, making ARC
-O3 defunct.

Fix that by NOT relying on any ordering whatsoever and use the proper
arch override facility now present in kbuild (ARCH_*FLAGS)

Depends-on: ("kbuild: Allow arch Makefiles to override {cpp,ld,c}flags")
Suggested-by: NMichal Marek <mmarek@suse.cz>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: stable@vger.kernel.org # 3.16+
Signed-off-by: NVineet Gupta <vgupta@synopsys.com>

Reported-by: NGuenter Roeck <private@roeck-us.net>
Signed-off-by: NVineet Gupta <vgupta@synopsys.com>

-no-ll64 is specific to ARCv2 ISA, and is obviously not supported by
older ARC gcc - in this case the one hosted by linux-next sanity build
service.

Ensure that it doesn't get included for ISA_ARCOMPACT
Reported-by: NGuenter Roeck <private@roeck-us.net>
Signed-off-by: NVineet Gupta <vgupta@synopsys.com>

The notable features are:
    - SMP configurations of upto 4 cores with coherency
    - Optional L2 Cache and IO-Coherency
    - Revised Interrupt Architecture (multiple priorites, reg banks,
        auto stack switch, auto regfile save/restore)
    - MMUv4 (PIPT dcache, Huge Pages)
    - Instructions for
	* 64bit load/store: LDD, STD
	* Hardware assisted divide/remainder: DIV, REM
	* Function prologue/epilogue: ENTER_S, LEAVE_S
	* IRQ enable/disable: CLRI, SETI
	* pop count: FFS, FLS
	* SETcc, BMSKN, XBFU...
Signed-off-by: NVineet Gupta <vgupta@synopsys.com>

The AXS10x platforms consist of a mainboard with peripherals,
on which several daughter cards can be placed. The daughter cards
typically contain a CPU and memory.
Signed-off-by: NMischa Jonker <mjonker@synopsys.com>
Signed-off-by: NAlexey Brodkin <abrodkin@synopsys.com>
Signed-off-by: NVineet Gupta <vgupta@synopsys.com>

* Remove remanants of legacy ARC FPGA platforms (AA4, ML509...)
* Only nsim simulation platform is left, rename platform accordingly
* AA4 DT stuff is compatible with nsim for ARC700 so rename it too
Signed-off-by: NVineet Gupta <vgupta@synopsys.com>

Signed-off-by: NVineet Gupta <vgupta@synopsys.com>

ARC GNU tools have had support for arc-linux-* driver for some time now.
This is functionally similar to arc-linux-uclibc-* but uclibc prefix
seemed weird at best when trying to compile the kernel itself.
Signed-off-by: NVineet Gupta <vgupta@synopsys.com>

Signed-off-by: NVineet Gupta <vgupta@synopsys.com>

Signed-off-by: NVineet Gupta <vgupta@synopsys.com>

* DWARF unwinder related
  + Force DWARF2 compliant .debug_frame (gcc 4.8 defaults to DWARF4
    which kernel unwinder can't grok).
  + Discard the additional .eh_frame generated
  + Discard the dwarf4 debug info generated by -gdwarf-2 for normal
    no debug case

* 4.8 already uses arc600 multilibs for -mno-mpy

* switch to using uclibc compiler (to get -mmedium-calls and -mno-sdata)
  and also since buildroot can only use 1 toolchain
Signed-off-by: NVineet Gupta <vgupta@synopsys.com>

Signed-off-by: NVineet Gupta <vgupta@synopsys.com>

Infrastructure required to make the Linux kernel compile and boot on the
Abilis Systems TB10x series of SOCs based on ARC700 CPUs:
  - Kmake related files (Kconfig, Makefile, tb10x_defconfig)
  - TB10x platform initialisation
Signed-off-by: NChristian Ruppert <christian.ruppert@abilis.com>
Signed-off-by: NPierrick Hascoet <pierrick.hascoet@abilis.com>
Signed-off-by: NVineet Gupta <vgupta@synopsys.com>