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Paul Burton 0fa24340f7 MIPS: Fix octeon FP context switch handling 
Commit 1a3d59579b ("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: 1a3d59579b ("MIPS: Tidy up FPU context switching")
Reported-by: Aaro Koskinen <aaro.koskinen@nokia.com>
Signed-off-by: Paul 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: Ralf Baechle <ralf@linux-mips.org>
2015-10-02 19:16:06 +02:00
..
alpha Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-09-18 08:11:42 -07:00
arc genirq: Remove irq argument from irq flow handlers 2015-09-16 15:47:51 +02:00
arm Merge branch 'fixes' of git://ftp.arm.linux.org.uk/~rmk/linux-arm 2015-09-19 21:05:02 -07:00
arm64 Mostly stable material, a lot of ARM fixes. 2015-09-18 09:23:08 -07:00
avr32 genirq: Remove irq argument from irq flow handlers 2015-09-16 15:47:51 +02:00
blackfin genirq: Remove irq argument from irq flow handlers 2015-09-16 15:47:51 +02:00
c6x genirq: Remove irq argument from irq flow handlers 2015-09-16 15:47:51 +02:00
cris CRISv10: delete unused lib/dmacopy.c 2015-09-05 00:56:51 +02:00
frv Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-09-03 15:46:07 -07:00
h8300 dma-mapping: consolidate dma_set_mask 2015-09-10 13:29:01 -07:00
hexagon Merge branch 'akpm' (patches from Andrew) 2015-09-10 18:19:42 -07:00
ia64 ia64: Enable userfaultfd and membarrier system calls 2015-09-15 16:22:45 -07:00
m32r lib/decompressors: use real out buf size for gunzip with kernel 2015-09-10 13:29:01 -07:00
m68k genirq: Remove irq argument from irq flow handlers 2015-09-16 15:47:51 +02:00
metag genirq: Remove irq argument from irq flow handlers 2015-09-16 15:47:51 +02:00
microblaze Merge branch 'akpm' (patches from Andrew) 2015-09-10 18:19:42 -07:00
mips MIPS: Fix octeon FP context switch handling 2015-10-02 19:16:06 +02:00
mn10300 Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-09-03 15:46:07 -07:00
nios2 nios2: add Max10 defconfig 2015-09-08 18:16:02 +08:00
openrisc dma-mapping: consolidate dma_set_mask 2015-09-10 13:29:01 -07:00
parisc parisc: Use platform_device_register_simple("rtc-generic") 2015-09-08 17:53:48 +02:00
powerpc Mostly stable material, a lot of ARM fixes. 2015-09-18 09:23:08 -07:00
s390 KVM: s390: Replace incorrect atomic_or with atomic_andnot 2015-09-16 17:01:06 +02:00
score Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-09-01 14:04:50 -07:00
sh genirq: Remove irq argument from irq flow handlers 2015-09-16 15:47:51 +02:00
sparc genirq: Remove irq argument from irq flow handlers 2015-09-16 15:47:51 +02:00
tile genirq: Remove irq argument from irq flow handlers 2015-09-16 15:47:51 +02:00
um Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-09-01 14:04:50 -07:00
unicore32 genirq: Remove irq argument from irq flow handlers 2015-09-16 15:47:51 +02:00
x86 Mostly stable material, a lot of ARM fixes. 2015-09-18 09:23:08 -07:00
xtensa dma-mapping: consolidate dma_set_mask 2015-09-10 13:29:01 -07:00
.gitignore
Kconfig kexec: split kexec_load syscall from kexec core code 2015-09-10 13:29:01 -07:00