Commit Graph

34 Commits

Author SHA1 Message Date
Linus Torvalds
6e8d666e92 Disable "maybe-uninitialized" warning globally
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: Linus Torvalds <torvalds@linux-foundation.org>
2016-07-27 13:17:41 -07:00
Vineet Gupta
f52e126cc7 ARC: unwind: ensure that .debug_frame is generated (vs. .eh_frame)
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: Vineet Gupta <vgupta@synopsys.com>
2016-06-28 09:42:28 +05:30
Andrea Gelmini
2547476a5e Fix typos
Signed-off-by: Andrea Gelmini <andrea.gelmini@gelma.net>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2016-05-30 10:07:32 +05:30
Noam Camus
966657890e ARC: Add eznps platform to Kconfig and Makefile
This commit should be left last since only now eznps platform
is in state which one can actually use.
Signed-off-by: Noam Camus <noamc@ezchip.com>
2016-05-09 09:32:33 +05:30
Vineet Gupta
a69fe1a2c9 ARC: build: Turn off -Wmaybe-uninitialized for ARC gcc 4.8
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: Vineet Gupta <vgupta@synopsys.com>
2016-03-18 16:22:36 +05:30
Vineet Gupta
20d780374c ARC: build: Better way to detect ISA compatible toolchain
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: Claudiu Zissulescu <claziss@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2016-03-12 11:58:30 +05:30
Vineet Gupta
89a269285f ARC: [BE] Select correct CROSS_COMPILE prefix
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: Vineet Gupta <vgupta@synopsys.com>
2016-03-11 14:59:54 +05:30
Vineet Gupta
0eca6fdb31 ARC: Assume multiplier is always present
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 <vgupta@synopsys.com>
2016-02-18 17:30:03 +05:30
Vineet Gupta
07fd7d4bbc ARC: Fix linking errors with CONFIG_MODULE + CONFIG_CC_OPTIMIZE_FOR_SIZE
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 <akolesov@synosys.com>
Cc: Michal Marek <mmarek@suse.cz>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2015-12-21 13:01:19 +05:30
Rob Herring
10375ccc67 arc: use common make variables for dtb builds
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 <robh@kernel.org>
Acked-by: Vineet Gupta <vgupta@synopsys.com>
2015-10-27 16:12:13 -05:00
Alexey Brodkin
d05a76ab4d ARCv2: add knob for DIV_REV in Kconfig
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 <abrodkin@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2015-07-20 13:33:30 +03:00
Vineet Gupta
9770906921 ARC: Override toplevel default -O2 with -O3
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 a1c48bb160 ("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: Michal Marek <mmarek@suse.cz>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: stable@vger.kernel.org # 3.16+
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2015-07-06 11:09:00 +05:30
Vineet Gupta
40b8ad8f76 ARC: Fix build failures for ARCompact in linux-next after ARCv2 support
Reported-by: Guenter Roeck <private@roeck-us.net>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2015-06-28 20:30:13 +05:30
Vineet Gupta
d1c6c2fbcd ARCv2: Allow older gcc to cope with new regime of ARCv2/ARCompact support
-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: Guenter Roeck <private@roeck-us.net>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2015-06-28 19:47:22 +05:30
Vineet Gupta
1f6ccfff63 ARCv2: Support for ARCv2 ISA and HS38x cores
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: Vineet Gupta <vgupta@synopsys.com>
2015-06-22 14:06:55 +05:30
Alexey Brodkin
556cc1c5f5 ARC: [axs101] Add support for AXS101 SDP (software development platform)
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: Mischa Jonker <mjonker@synopsys.com>
Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2015-06-19 18:09:30 +05:30
Vineet Gupta
fd1557923b ARC: [plat_arcfpga]->[plat_sim]
* 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: Vineet Gupta <vgupta@synopsys.com>
2015-06-19 18:09:26 +05:30
Vineet Gupta
565a9b497c ARC: RIP broken 64bit RTSC
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2015-06-19 18:09:24 +05:30
Vineet Gupta
7c42eaf6c5 ARC: switch to simpler CROSS_COMPILE prefix
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: Vineet Gupta <vgupta@synopsys.com>
2015-05-19 11:27:13 +05:30
Vineet Gupta
7a70bf797a ARC: rename default defconfig
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2014-12-17 15:23:56 +05:30
Vineet Gupta
68d8feee85 ARC: remove gcc mpy heuristics
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2014-10-13 14:46:17 +05:30
Vineet Gupta
5a45da02cf ARC: Adjustments for gcc 4.8
* 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: Vineet Gupta <vgupta@synopsys.com>
2013-06-27 14:35:32 +05:30
Vineet Gupta
8235703e10 ARC: Use kconfig helper IS_ENABLED() to get rid of defines.h
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2013-06-22 13:46:42 +05:30
Christian Ruppert
072eb69390 ARC: [TB10x] Add support for TB10x platform
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: Christian Ruppert <christian.ruppert@abilis.com>
Signed-off-by: Pierrick Hascoet <pierrick.hascoet@abilis.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2013-05-07 13:43:59 +05:30
Vineet Gupta
104058ede7 ARC: [build] Allow uncompressed uImage
The existing uImage target always generates gzip compressed image which
drags bootup for some very slow FPGA customer boards.

So introduce seperate make targets:uImage.{bin,gz} with uncompressed
being default. Also tie gz generation to CONFIG_KERNEL_GZIP, which a
platform can select in it's Kconfig if it wishes gz to be default.

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2013-04-09 12:21:15 +05:30
Vineet Gupta
fb0990bbf5 ARC: [build] cleanup Makefile a bit
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2013-04-09 12:21:15 +05:30
Vineet Gupta
af4c3ae399 ARC: [build] silence make defconfig warnings with host gcc 4.7
We do cross compiles for ARC Linux.
With gcc 4.7, a make defconfig spews out the following:

------------------->8--------------------------
make ARCH=arc defconfig
gcc: error: unrecognized command line option '-marc600'
gcc: error: unrecognized command line option '-mA7'
gcc: error: unrecognized command line option '-mno-sdata'
gcc: error: unrecognized command line option '-mno-mpy'
*** Default configuration is based on 'fpga_defconfig'
------------------->8--------------------------

This apparently is coming from LIBGCC line - which is strange to be
invoked for defconfig generation.

Reported-by: Alexey Brodkin <abrodkin@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2013-04-09 12:21:15 +05:30
Vineet Gupta
e97ff121ae ARC: [Review] Multi-platform image #4: Isolate platform headers
-Top level ARC makefile removes -I for platform headers
-asm/irq.h no longer includes plat/irq.h

-platform makefile adds -I for it's specfic platform headers
-platform code to directly include it's plat/irq.h

-Linker script needed plat/memmap.h for CCM info, already in .config

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Acked-by: Arnd Bergmann <arnd@arndb.de>
2013-02-15 23:16:14 +05:30
Vineet Gupta
af61742813 ARC: Boot #2: Verbose Boot reporting / feature verification
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2013-02-15 23:16:07 +05:30
Vineet Gupta
41195d236e ARC: SMP support
ARC common code to enable a SMP system + ISS provided SMP extensions.

ARC700 natively lacks SMP support, hence some of the core features are
are only enabled if SoCs have the necessary h/w pixie-dust. This
includes:
-Inter Processor Interrupts (IPI)
-Cache coherency
-load-locked/store-conditional
...

The low level exception handling would be completely broken in SMP
because we don't have hardware assisted stack switching. Thus a fair bit
of this code is repurposing the MMU_SCRATCH reg for event handler
prologues to keep them re-entrant.

Many thanks to Rajeshwar Ranga for his initial "major" contributions to
SMP Port (back in 2008), and to Noam Camus and Gilad Ben-Yossef for help
with resurrecting that in 3.2 kernel (2012).

Note that this platform code is again singleton design pattern - so
multiple SMP platforms won't build at the moment - this deficiency is
addressed in subsequent patches within this series.

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Rajeshwar Ranga <rajeshwar.ranga@gmail.com>
Cc: Noam Camus <noamc@ezchip.com>
Cc: Gilad Ben-Yossef <gilad@benyossef.com>
2013-02-15 23:16:02 +05:30
Vineet Gupta
769bc1fd7b ARC: OProfile support
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Cc: Robert Richter <rric@kernel.org>
Cc: oprofile-list@lists.sf.net
Reviewed-by: James Hogan <james.hogan@imgtec.com>
2013-02-15 23:16:00 +05:30
Vineet Gupta
080c37473e ARC: [optim] Cache "current" in Register r25
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2013-02-15 23:15:58 +05:30
Vineet Gupta
999159a538 ARC: [DeviceTree] Basic support
This is minimal infrastructure needed for devicetree work.
It uses an a sample "skeleton" devicetree - embedded in kernel image -
to print the board, manufacturer by parsing the top-level "compatible"
string.

As of now we don't need any additional "board" specific "machine_desc".

TODO: support interpreting the command line as boot-loader passed dtb

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: devicetree-discuss@lists.ozlabs.org
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: James Hogan <james.hogan@imgtec.com>
Reviewed-by: Rob Herring <rob.herring@calxeda.com>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
2013-02-15 23:15:55 +05:30
Vineet Gupta
cfdbc2e16e ARC: Build system: Makefiles, Kconfig, Linker script
Arnd in his review pointed out that arch Kconfig organisation has several
deficiencies:

* Build time entries for things which can be runtime extracted from DT
  (e.g. SDRAM size, core clk frequency..)
* Not multi-platform-image-build friendly (choice .. endchoice constructs)
* cpu variants support (750/770) is exclusive.

The first 2 have been fixed in subsequent patches.
Due to the nature of the 750 and 770, it is not possible to build for
both together, w/o special runtime glue code which would hurt
performance.

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
2013-02-11 20:00:25 +05:30