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Babu Moger 4c97a0c8fe arch: define CPU_BIG_ENDIAN for all fixed big endian archs 
Patch series "Define CPU_BIG_ENDIAN or warn for inconsistencies", v3.

While working on enabling queued rwlock on SPARC, found this following
code in include/asm-generic/qrwlock.h which uses CONFIG_CPU_BIG_ENDIAN to
clear a byte.

static inline u8 *__qrwlock_write_byte(struct qrwlock *lock)
 {
	return (u8 *)lock + 3 * IS_BUILTIN(CONFIG_CPU_BIG_ENDIAN);
 }

Problem is many of the fixed big endian architectures don't define
CPU_BIG_ENDIAN and clears the wrong byte.

Define CPU_BIG_ENDIAN for all the fixed big endian architecture to fix it.

Also found few more references of this config parameter in
drivers/of/base.c
drivers/of/fdt.c
drivers/tty/serial/earlycon.c
drivers/tty/serial/serial_core.c
Be aware that this may cause regressions if someone has worked-around
problems in the above code already. Remove the work-around.

Here is our original discussion
https://lkml.org/lkml/2017/5/24/620

Link: http://lkml.kernel.org/r/1499358861-179979-2-git-send-email-babu.moger@oracle.com
Signed-off-by: Babu Moger <babu.moger@oracle.com>
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Stafford Horne <shorne@gmail.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Helge Deller <deller@gmx.de>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-09-08 18:26:48 -07:00
..
boot/dts openrisc: use new common dtc rule 2012-12-03 17:17:48 -06:00
configs openrisc: defconfig: Cleanup from old Kconfig options 2017-07-08 04:35:30 +09:00
include futex: Remove duplicated code and fix undefined behaviour 2017-08-25 22:49:59 +02:00
kernel OpenRISC fixes for 4.13 2017-07-07 13:58:49 -07:00
lib openrisc: Switch to use export.h instead of module.h 2017-05-15 22:02:33 +09:00
mm sched/headers: Prepare for new header dependencies before moving code to <linux/sched/signal.h> 2017-03-02 08:42:29 +01:00
Kconfig arch: define CPU_BIG_ENDIAN for all fixed big endian archs 2017-09-08 18:26:48 -07:00
Makefile openrisc: Makefile: append "-D__linux__" to KBUILD_CFLAGS 2013-11-05 16:14:47 +01:00
README.openrisc openrisc: Updates after openrisc.net has been lost 2016-12-12 23:10:19 +09:00
TODO.openrisc openrisc: Add optimized memcpy routine 2017-02-25 04:14:36 +09:00

README.openrisc 

OpenRISC Linux
==============

This is a port of Linux to the OpenRISC class of microprocessors; the initial
target architecture, specifically, is the 32-bit OpenRISC 1000 family (or1k).

For information about OpenRISC processors and ongoing development:

	website		http://openrisc.io

For more information about Linux on OpenRISC, please contact South Pole AB.

	email:		info@southpole.se

	website:	http://southpole.se
			http://southpoleconsulting.com

---------------------------------------------------------------------

Build instructions for OpenRISC toolchain and Linux
===================================================

In order to build and run Linux for OpenRISC, you'll need at least a basic
toolchain and, perhaps, the architectural simulator.  Steps to get these bits
in place are outlined here.

1)  The toolchain can be obtained from openrisc.io.  Instructions for building
a toolchain can be found at:

https://github.com/openrisc/tutorials

2) or1ksim (optional)

or1ksim is the architectural simulator which will allow you to actually run
your OpenRISC Linux kernel if you don't have an OpenRISC processor at hand.

	git clone https://github.com/openrisc/or1ksim.git

	cd or1ksim
	./configure --prefix=$OPENRISC_PREFIX
	make
	make install

3)  Linux kernel

Build the kernel as usual

	make ARCH=openrisc defconfig
	make ARCH=openrisc

4)  Run in architectural simulator

Grab the or1ksim platform configuration file (from the or1ksim source) and
together with your freshly built vmlinux, run your kernel with the following
incantation:

	sim -f arch/openrisc/or1ksim.cfg vmlinux

---------------------------------------------------------------------

Terminology
===========

In the code, the following particles are used on symbols to limit the scope
to more or less specific processor implementations:

openrisc: the OpenRISC class of processors
or1k:     the OpenRISC 1000 family of processors
or1200:   the OpenRISC 1200 processor

---------------------------------------------------------------------

History
========

18. 11. 2003	Matjaz Breskvar (phoenix@bsemi.com)
	initial port of linux to OpenRISC/or32 architecture.
        all the core stuff is implemented and seams usable.

08. 12. 2003	Matjaz Breskvar (phoenix@bsemi.com)
	complete change of TLB miss handling.
	rewrite of exceptions handling.
	fully functional sash-3.6 in default initrd.
	a much improved version with changes all around.

10. 04. 2004	Matjaz Breskvar (phoenix@bsemi.com)
	alot of bugfixes all over.
	ethernet support, functional http and telnet servers.
	running many standard linux apps.

26. 06. 2004	Matjaz Breskvar (phoenix@bsemi.com)
	port to 2.6.x

30. 11. 2004	Matjaz Breskvar (phoenix@bsemi.com)
	lots of bugfixes and enhancments.
	added opencores framebuffer driver.

09. 10. 2010    Jonas Bonn (jonas@southpole.se)
	major rewrite to bring up to par with upstream Linux 2.6.36