linux-stable.git/arch/arc/Makefile, branch linux-4.4.y

ARC: build: add boot_targets to PHONY

2021-01-23T14:36:54+00:00

[ Upstream commit 0cfccb3c04934cdef42ae26042139f16e805b5f7 ]

The top-level boot_targets (uImage and uImage.*) should be phony
targets. They just let Kbuild descend into arch/arc/boot/ and create
files there.

If a file exists in the top directory with the same name, the boot
image will not be created.

You can confirm it by the following steps:

  $ export CROSS_COMPILE=
  $ make -s ARCH=arc defconfig all   # vmlinux will be built
  $ touch uImage.gz
  $ make ARCH=arc uImage.gz
  CALL    scripts/atomic/check-atomics.sh
  CALL    scripts/checksyscalls.sh
  CHK     include/generated/compile.h
  # arch/arc/boot/uImage.gz is not created

Specify the targets as PHONY to fix this.

Signed-off-by: Masahiro Yamada 
Signed-off-by: Vineet Gupta 
Signed-off-by: Sasha Levin

ARC: Assume multiplier is always present

2019-07-10T07:56:41+00:00

[ Upstream commit 0eca6fdb3193410fbe66b6f064431cc394513e82 ]

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: Vineet Gupta 
Signed-off-by: Sasha Levin

ARC: change defconfig defaults to ARCv2

2018-12-13T08:21:32+00:00

commit b7cc40c32a8bfa6f2581a71747f6a7d491fe43ba upstream.

Change the default defconfig (used with 'make defconfig') to the ARCv2
nsim_hs_defconfig, and also switch the default Kconfig ISA selection to
ARCv2.

This allows several default defconfigs (e.g. make defconfig, make
allnoconfig, make tinyconfig) to all work with ARCv2 by default.

Note since we change default architecture from ARCompact to ARCv2
it's required to explicitly mention architecture type in ARCompact
defconfigs otherwise ARCv2 will be implied and binaries will be
generated for ARCv2.

Cc:  # 4.4.x
Signed-off-by: Kevin Hilman 
Signed-off-by: Alexey Brodkin 
Signed-off-by: Vineet Gupta 
Signed-off-by: Greg Kroah-Hartman

ARC: build: Get rid of toolchain check

2018-10-20T07:52:38+00:00

commit 615f64458ad890ef94abc879a66d8b27236e733a upstream.

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: Rob Herring 
Signed-off-by: Alexey Brodkin 
Signed-off-by: Vineet Gupta 
Signed-off-by: Greg Kroah-Hartman

ARC: Explicitly add -mmedium-calls to CFLAGS

2018-08-24T11:26:53+00:00

[ Upstream commit 74c11e300c103af47db5b658fdcf28002421e250 ]

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: Alexey Brodkin 
Signed-off-by: Vineet Gupta 

Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

ARC: build: Better way to detect ISA compatible toolchain

2016-09-07T06:32:42+00:00

commit 20d780374c81cf237834af2202c26df2100ddd69 upstream.

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 
Suggested-by: Claudiu Zissulescu 
Signed-off-by: Vineet Gupta 
Signed-off-by: Greg Kroah-Hartman

ARC: unwind: ensure that .debug_frame is generated (vs. .eh_frame)

2016-08-10T09:49:25+00:00

commit f52e126cc7476196f44f3c313b7d9f0699a881fc upstream.

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

Signed-off-by: Vineet Gupta 
Signed-off-by: Greg Kroah-Hartman

ARC: Fix linking errors with CONFIG_MODULE + CONFIG_CC_OPTIMIZE_FOR_SIZE

2015-12-21T07:31:19+00:00

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: Anton Kolesov 
Cc: Michal Marek 
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Vineet Gupta

arc: use common make variables for dtb builds

2015-10-27T21:12:13+00:00

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: Rob Herring 
Acked-by: Vineet Gupta

ARCv2: add knob for DIV_REV in Kconfig

2015-07-20T10:33:30+00:00

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: Alexey Brodkin 
Signed-off-by: Vineet Gupta