Move _save_fp(), _restore_fp(), _save_msa(), _restore_msa(),
_init_msa_upper() & _init_fpu() out of r4k_switch.S & into r4k_fpu.S.
This allows us to clean up the way in which Octeon includes the default
r4k implementations of these FP functions despite replacing resume(),
and makes CONFIG_R4K_FPU more straightforwardly represent all
configurations that have an R4K-style FPU, including Octeon.

Besides cleaning up this will be useful for later patches which disable
FP support.

[ralf@linux-mips.org: Fixed build issues reported by Arnd Bergmann
<arnd@arndb.de>]
Signed-off-by: NPaul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16237/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Commit 1a3d5957 ("MIPS: Tidy up FPU context switching") removed FP
context saving from the asm-written resume function in favour of reusing
existing code to perform the same task. However it only removed the FP
context saving code from the r4k_switch.S implementation of resume.
Octeon uses its own implementation in octeon_switch.S, so remove FP
context saving there too in order to prevent attempting to save context
twice. That formerly led to an exception from the second save as follows
because the FPU had already been disabled by the first save:

    do_cpu invoked from kernel context![#1]:
    CPU: 0 PID: 2 Comm: kthreadd Not tainted 4.3.0-rc2-dirty #2
    task: 800000041f84a008 ti: 800000041f864000 task.ti: 800000041f864000
    $ 0   : 0000000000000000 0000000010008ce1 0000000000100000 ffffffffbfffffff
    $ 4   : 800000041f84a008 800000041f84ac08 800000041f84c000 0000000000000004
    $ 8   : 0000000000000001 0000000000000000 0000000000000000 0000000000000001
    $12   : 0000000010008ce3 0000000000119c60 0000000000000036 800000041f864000
    $16   : 800000041f84ac08 800000000792ce80 800000041f84a008 ffffffff81758b00
    $20   : 0000000000000000 ffffffff8175ae50 0000000000000000 ffffffff8176c740
    $24   : 0000000000000006 ffffffff81170300
    $28   : 800000041f864000 800000041f867d90 0000000000000000 ffffffff815f3fa0
    Hi    : 0000000000fa8257
    Lo    : ffffffffe15cfc00
    epc   : ffffffff8112821c resume+0x9c/0x200
    ra    : ffffffff815f3fa0 __schedule+0x3f0/0x7d8
    Status: 10008ce2        KX SX UX KERNEL EXL
    Cause : 1080002c (ExcCode 0b)
    PrId  : 000d0601 (Cavium Octeon+)
    Modules linked in:
    Process kthreadd (pid: 2, threadinfo=800000041f864000, task=800000041f84a008, tls=0000000000000000)
    Stack : ffffffff81604218 ffffffff815f7e08 800000041f84a008 ffffffff811681b0
              800000041f84a008 ffffffff817e9878 0000000000000000 ffffffff81770000
              ffffffff81768340 ffffffff81161398 0000000000000001 0000000000000000
              0000000000000000 ffffffff815f4424 0000000000000000 ffffffff81161d68
              ffffffff81161be8 0000000000000000 0000000000000000 0000000000000000
              0000000000000000 0000000000000000 0000000000000000 ffffffff8111e16c
              0000000000000000 0000000000000000 0000000000000000 0000000000000000
              0000000000000000 0000000000000000 0000000000000000 0000000000000000
              0000000000000000 0000000000000000 0000000000000000 0000000000000000
              0000000000000000 0000000000000000 0000000000000000 0000000000000000
              ...
    Call Trace:
    [<ffffffff8112821c>] resume+0x9c/0x200
    [<ffffffff815f3fa0>] __schedule+0x3f0/0x7d8
    [<ffffffff815f4424>] schedule+0x34/0x98
    [<ffffffff81161d68>] kthreadd+0x180/0x198
    [<ffffffff8111e16c>] ret_from_kernel_thread+0x14/0x1c

Tested using cavium_octeon_defconfig on an EdgeRouter Lite.

Fixes: 1a3d5957 ("MIPS: Tidy up FPU context switching")
Reported-by: NAaro Koskinen <aaro.koskinen@nokia.com>
Signed-off-by: NPaul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Aleksey Makarov <aleksey.makarov@auriga.com>
Cc: linux-kernel@vger.kernel.org
Cc: Chandrakala Chavva <cchavva@caviumnetworks.com>
Cc: David Daney <david.daney@cavium.com>
Cc: Leonid Rosenboim <lrosenboim@caviumnetworks.com>
Patchwork: https://patchwork.linux-mips.org/patch/11166/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Commit 2c952e06 ("MIPS: Move cop2 save/restore to switch_to()")
removes assembler code to store COP2 registers.  Commit
a36d8225 ("MIPS: OCTEON: Enable use of FPU") mistakenly
restores it

Fixes: a36d8225 ("MIPS: OCTEON: Enable use of FPU")
Signed-off-by: NAleksey Makarov <aleksey.makarov@auriga.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Cc: David Daney <david.daney@cavium.com>
Patchwork: https://patchwork.linux-mips.org/patch/8937/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Use dmfc0/dmtc0 instructions for reading CvmMemCtl COP0 register,
its a 64-bit wide.
Signed-off-by: NChandrakala Chavva <cchavva@caviumnetworks.com>
Signed-off-by: NAleksey Makarov <aleksey.makarov@auriga.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Cc: David Daney <david.daney@cavium.com>
Patchwork: https://patchwork.linux-mips.org/patch/8936/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Allocate new save space, and then save/restore the registers if
OCTEON III.
Signed-off-by: NDavid Daney <david.daney@cavium.com>
Signed-off-by: NAleksey Makarov <aleksey.makarov@auriga.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/8935/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

It wasn't being saved on task switch.
Signed-off-by: NDavid Daney <david.daney@cavium.com>
Signed-off-by: NAleksey Makarov <aleksey.makarov@auriga.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/8934/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

The wide multiplier is twice as wide, so we need to save twice as much
state.  Detect the multiplier type (CPU type) at start up and install
model specific handlers.

[aleksey.makarov@auriga.com:
	conflict resolution,
	support for old compilers]
Signed-off-by: NDavid Daney <david.daney@cavium.com>
Signed-off-by: NLeonid Rosenboim <lrosenboim@caviumnetworks.com>
Signed-off-by: NAleksey Makarov <aleksey.makarov@auriga.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/8933/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Some versions of the assembler will not assemble CFC1 for OCTEON, so
override the ISA for these.

Add r4k_fpu.o to handle low level FPU initialization.

Modify octeon_switch.S to save the FPU registers.  And include
r4k_switch.S to pick up more FPU support.

Get rid of "#define cpu_has_fpu		0"
Signed-off-by: NDavid Daney <david.daney@cavium.com>
Signed-off-by: NAndreas Herrmann <andreas.herrmann@caviumnetworks.com>
Cc: linux-mips@linux-mips.org
Cc: James Hogan <james.hogan@imgtec.com>
Cc: kvm@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/7006/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Commit 1400eb65 (MIPS: r4k,octeon,r2300: stack protector: change canary
per task) was merged in v3.11 and introduced assembly in the MIPS resume
functions to update the value of the current canary in
__stack_chk_guard. However it used PTR_L resulting in a load of the
canary value, instead of PTR_LA to construct its address. The value is
intended to be random but is then treated as an address in the
subsequent LONG_S (store).

This was observed to cause a fault and panic:

CPU 0 Unable to handle kernel paging request at virtual address 139fea20, epc == 8000cc0c, ra == 8034f2a4
Oops[#1]:
...
$24   : 139fea20 1e1f7cb6
...
Call Trace:
[<8000cc0c>] resume+0xac/0x118
[<8034f2a4>] __schedule+0x5f8/0x78c
[<8034f4e0>] schedule_preempt_disabled+0x20/0x2c
[<80348eec>] rest_init+0x74/0x84
[<804dc990>] start_kernel+0x43c/0x454
Code: 3c18804b  8f184030  8cb901f8 <af190000> 00c0e021  8cb002f0 8cb102f4  8cb202f8  8cb302fc

This can also be forced by modifying
arch/mips/include/asm/stackprotector.h so that the default
__stack_chk_guard value is more likely to be a bad (or unaligned)
pointer.

Fix it to use PTR_LA instead, to load the address of the canary value,
which the LONG_S can then use to write into it.

Reported-by: bobjones (via #mipslinux on IRC)
Signed-off-by: NJames Hogan <james.hogan@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Gregory Fong <gregory.0xf0@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: stable@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/6026/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

For non-SMP, uses the new random canary value that is stored in the
task struct whenever a new task is forked.  Based on ARM version in
df0698be and subject to the same
limitations: the variable GCC expects, __stack_chk_guard, is global,
so this will not work on SMP.

Quoting Nicolas Pitre <nico@fluxnic.net>: "One way to overcome this
GCC limitation would be to locate the __stack_chk_guard variable into
a memory page of its own for each CPU, and then use TLB locking to
have each CPU see its own page at the same virtual address for each of
them."
Signed-off-by: NGregory Fong <gregory.0xf0@gmail.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/5488/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Move the common code for saving and restoring platform specific COP2
registers to switch_to(). This will make supporting new platforms (like
Netlogic XLP) easier.

The platform specific COP2 definitions are to be specified in
asm/processor.h and in asm/cop2.h.
Signed-off-by: NJayachandran C <jchandra@broadcom.com>
Cc: linux-mips@linux-mips.org
Cc: ddaney.cavm@gmail.com
Patchwork: https://patchwork.linux-mips.org/patch/5411/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Having received another series of whitespace patches I decided to do this
once and for all rather than dealing with this kind of patches trickling
in forever.
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

So far we're jumping through hoops to keep the file usable from assembler
source but it's getting just too painful.  Turns out that many uses of
<asm/page.h> are unnecessary anyway, so just remove those.
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

[ralf@linux-mips.org: Cosmetic changes; also fixed up r2300_switch.S and
octeon_switch.S which needed similar modifications.]
Signed-off-by: NLeonid Yegoshin <yegoshin@mips.com>
Signed-off-by: NSteven J. Hill <sjhill@mips.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/3784/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Signed-off-by: NJustin P. Mattock <justinmattock@gmail.com>
Acked-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

Recent git versions now warn about those and they've always been a bit of
an annoyance.
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

These are the rest of the new files needed to add OCTEON processor
support to the Linux kernel.  Other than Makefile and Kconfig which
should be obvious, we have:

csrc-octeon.c   -- Clock source driver for OCTEON.
dma-octeon.c    -- Helper functions for mapping DMA memory.
flash_setup.c   -- Register on-board flash with the MTD subsystem.
octeon-irq.c    -- OCTEON interrupt controller managment.
octeon-memcpy.S -- Optimized memcpy() implementation.
serial.c        -- Register 8250 platform driver and early console.
setup.c         -- Early architecture initialization.
smp.c           -- OCTEON SMP support.
octeon_switch.S -- Scheduler context switch for OCTEON.
c-octeon.c      -- OCTEON cache controller support.
cex-oct.S       -- OCTEON cache exception handler.

asm/mach-cavium-octeon/*.h -- Architecture include files.
Signed-off-by: NTomaso Paoletti <tpaoletti@caviumnetworks.com>
Signed-off-by: NDavid Daney <ddaney@caviumnetworks.com>
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

 create mode 100644 arch/mips/cavium-octeon/Kconfig
 create mode 100644 arch/mips/cavium-octeon/Makefile
 create mode 100644 arch/mips/cavium-octeon/csrc-octeon.c
 create mode 100644 arch/mips/cavium-octeon/dma-octeon.c
 create mode 100644 arch/mips/cavium-octeon/flash_setup.c
 create mode 100644 arch/mips/cavium-octeon/octeon-irq.c
 create mode 100644 arch/mips/cavium-octeon/octeon-memcpy.S
 create mode 100644 arch/mips/cavium-octeon/serial.c
 create mode 100644 arch/mips/cavium-octeon/setup.c
 create mode 100644 arch/mips/cavium-octeon/smp.c
 create mode 100644 arch/mips/include/asm/mach-cavium-octeon/cpu-feature-overrides.h
 create mode 100644 arch/mips/include/asm/mach-cavium-octeon/dma-coherence.h
 create mode 100644 arch/mips/include/asm/mach-cavium-octeon/irq.h
 create mode 100644 arch/mips/include/asm/mach-cavium-octeon/kernel-entry-init.h
 create mode 100644 arch/mips/include/asm/mach-cavium-octeon/war.h
 create mode 100644 arch/mips/include/asm/octeon/octeon.h
 create mode 100644 arch/mips/kernel/octeon_switch.S
 create mode 100644 arch/mips/mm/c-octeon.c
 create mode 100644 arch/mips/mm/cex-oct.S