This patch refactors the early init parsing of the chosen node so that
architectures aren't forced to provide an empty implementation of
early_init_dt_scan_chosen_arch.  Instead, if an architecture wants to
do something different, it can either use a wrapper function around
early_init_dt_scan_chosen(), or it can replace it altogether.

This patch was written in preparation to adding device tree support to
both x86 ad MIPS.
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>
Tested-by: NDavid Daney <ddaney@caviumnetworks.com>

New microblaze systems uses two buses. One for memories
and flashes and the second for low-speed peripherals
which can run on different CLK. This is the reason
why the kernel is trying to read clock-frequency
directly from node. If there is then the kernel will
work with it. If not then cpu CLK is used.
Signed-off-by: NMichal Simek <monstr@monstr.eu>

Microblaze little-endian toolchain exports __MICROBLAZEEL__
which is used in the kernel to identify little/big endian.

The most of the changes are in loading values from DTB which
is always big endian.

Little endian platforms are based on new AXI bus which has
impact to early uartlite initialization.
Signed-off-by: NMichal Simek <monstr@monstr.eu>

Just need to use little-endian opcode for brki r16, 0x18
Signed-off-by: NMichal Simek <monstr@monstr.eu>
CC: Jason Wessel <jason.wessel@windriver.com>

Upcomming microblaze version will support little-endian.
Signed-off-by: NMichal Simek <monstr@monstr.eu>
Acked-by: NGrant Likely <grant.likely@secretlab.ca>

Early console support reuse setting from U-BOOT that's why
it is not necessary to setup baudrates, etc.
Signed-off-by: NMichal Simek <monstr@monstr.eu>

Kconfig blocks to select any other early console support that's why
this patch has no real impact on current kernel version. But it is done
because of uart16550.
Signed-off-by: NMichal Simek <monstr@monstr.eu>

Just setup pointer early console in run time.
Signed-off-by: NMichal Simek <monstr@monstr.eu>

This is done because of uart16550 early printk support
Signed-off-by: NMichal Simek <monstr@monstr.eu>

Device-tree BSP generates longer compatible properties
that's why we can remove extra/old one.
Signed-off-by: NMichal Simek <monstr@monstr.eu>

It comes from past where pvr wasn't supported in msr instruction.
Signed-off-by: NMichal Simek <monstr@monstr.eu>

Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NMichal Simek <monstr@monstr.eu>

Several kernel modules requires empty_zero_page and mbc
to be exported.
Signed-off-by: NMichal Simek <monstr@monstr.eu>

Replaced libgcc functions with asm optimized implementation.
Signed-off-by: NMichal Simek <monstr@monstr.eu>

Signed-off-by: NMichal Simek <monstr@monstr.eu>

PVR for 7.30.b, 8.00.a versions.
Signed-off-by: NMichal Simek <monstr@monstr.eu>

OUTPUT_FORMAT setup bigendian platform. Microblaze Linux port
is becoming bi endian that's why it is removed.
Signed-off-by: NMichal Simek <monstr@monstr.eu>

r16 and r17 should be saved across interrupt and exception handling.
Signed-off-by: NMichal Simek <monstr@monstr.eu>

Kernel needs two timers because of clocksource and clockevent.
It is better to show warning message directly on early
console if available. If it isn't available kernel log buffer
contains it.
Signed-off-by: NMichal Simek <monstr@monstr.eu>

Signal code uses r3 value which saved in restore_sigcontext to
rt_sigframe but it require to be zeroed. If is not zero rt_sigframe
contains wrong values.
Signed-off-by: NMichal Simek <monstr@monstr.eu>

Do not save return registers before rt_sigreturn is called.
_user_exception(syscall handler) already setup return address
that's why it is removed from rt_sigreturn_wrapper.
Signed-off-by: NMichal Simek <monstr@monstr.eu>

Old gdb uses priviledged exception handler to handle
gdb exception. New gdb uses brki r16, 0x18 that's why
we can remove old gdb support.
Signed-off-by: NMichal Simek <monstr@monstr.eu>

I forget to remove unused variable from kgdb_arch_handle_exception.
Fix return value in microblaze_kgdb_break function.

Error log:
arch/microblaze/kernel/kgdb.c: In function 'microblaze_kgdb_break':
arch/microblaze/kernel/kgdb.c:83: warning: 'return' with a value, in function returning void
arch/microblaze/kernel/kgdb.c: In function 'kgdb_arch_handle_exception':
arch/microblaze/kernel/kgdb.c:119: warning: unused variable 'cpu'
Signed-off-by: NMichal Simek <monstr@monstr.eu>

Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NMichal Simek <monstr@monstr.eu>

Make do_execve() take a const filename pointer so that kernel_execve() compiles
correctly on ARM:

arch/arm/kernel/sys_arm.c:88: warning: passing argument 1 of 'do_execve' discards qualifiers from pointer target type

This also requires the argv and envp arguments to be consted twice, once for
the pointer array and once for the strings the array points to.  This is
because do_execve() passes a pointer to the filename (now const) to
copy_strings_kernel().  A simpler alternative would be to cast the filename
pointer in do_execve() when it's passed to copy_strings_kernel().

do_execve() may not change any of the strings it is passed as part of the argv
or envp lists as they are some of them in .rodata, so marking these strings as
const should be fine.

Further kernel_execve() and sys_execve() need to be changed to match.

This has been test built on x86_64, frv, arm and mips.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Tested-by: NRalf Baechle <ralf@linux-mips.org>
Acked-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit dbbdee94 removed
of_irq_pci_swizzle but didn't use pci_swizzle_interrupt_pin
instead.
Signed-off-by: NMichal Simek <monstr@monstr.eu>
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>

Mark arguments to certain system calls as being const where they should be but
aren't.  The list includes:

 (*) The filename arguments of various stat syscalls, execve(), various utimes
     syscalls and some mount syscalls.

 (*) The filename arguments of some syscall helpers relating to the above.

 (*) The buffer argument of various write syscalls.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Acked-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Kgdb uses brki r16, 0x18 instruction to call
low level _debug_exception function which save
current state to pt_regs and call microblaze_kgdb_break
function. _debug_exception should be called only from
the kernel space. User space calling is not supported
because user application debugging uses different handling.

pt_regs_to_gdb_regs loads additional special registers
which can't be changed

 * Enable KGDB in Kconfig
 * Remove ancient not-tested KGDB support
 * Remove ancient _debug_exception code from entry.S

Only MMU KGDB support is supported.
Signed-off-by: NMichal Simek <monstr@monstr.eu>
CC: Jason Wessel <jason.wessel@windriver.com>
CC: John Williams <john.williams@petalogix.com>
CC: Edgar E. Iglesias <edgar.iglesias@petalogix.com>
CC: linux-kernel@vger.kernel.org
Acked-by: NJason Wessel <jason.wessel@windriver.com>

This is the first patch which add support for
user application debugging through brki rX, 0x18 vector.

This patch has side effect which also remove security issue
to use brki rX, 0x18 to freeze kernel.

Support for old gdb support via priviledged exception
(brk r0, r0) is still there. It will be remove in future.
Signed-off-by: NMichal Simek <monstr@monstr.eu>

We need to save instruction and the latest Microblaze shouldn't
have any problem with it.
Signed-off-by: NMichal Simek <monstr@monstr.eu>

Syscall can be called only from userspace that's why
we don't need to check which space kernel come from.

Kernel syscall calling is not check and shouldn't come
throught this part of code.
Signed-off-by: NMichal Simek <monstr@monstr.eu>

We can save one more instruction if PT_MODE is saved in delay slot
Signed-off-by: NMichal Simek <monstr@monstr.eu>

Save instructions by using delay slot and
clear UMS only if kernel comes from user space.
Signed-off-by: NMichal Simek <monstr@monstr.eu>

Saving some instructions. Clear VMS bit if kernel comes
from kernel space.
Signed-off-by: NMichal Simek <monstr@monstr.eu>

Saving instructions by adding 2/3 addik instructions to one.
Signed-off-by: NMichal Simek <monstr@monstr.eu>

Saving instruction with delay slot usage.
Signed-off-by: NMichal Simek <monstr@monstr.eu>

This change save one instruction if kernel comes from kernel
space.
Signed-off-by: NMichal Simek <monstr@monstr.eu>

Separate reg saving and mode setting.
Signed-off-by: NMichal Simek <monstr@monstr.eu>

SAVE_STATE macro could be used by other rutines too.
Signed-off-by: NMichal Simek <monstr@monstr.eu>

We are not working with values from MSR that's why
we can discard it and use r11 for different purpose without
saving/restoring.
Signed-off-by: NMichal Simek <monstr@monstr.eu>