Programming Languages Research Group: Git - firefly-linux-kernel-4.4.55.git/log

MIPS: Add definitions for extended context

The context introduced by MSA needs to be saved around signals. However,
we can't increase the size of struct sigcontext because that will change
the offset of the signal mask in struct sigframe or struct ucontext.
This patch instead places the new context immediately after the struct
sigframe for traditional signals, or similarly after struct ucontext for
RT signals. The layout of struct sigframe & struct ucontext is identical
from their sigcontext fields onwards, so the offset from the sigcontext
to the extended context will always be the same regardless of the type
of signal.

Userland will be able to search through the extended context by using
the magic values to detect which types of context are present. Any
unrecognised context can be skipped over using the size field of struct
extcontext. Once the magic value END_EXTCONTEXT_MAGIC is seen it is
known that there are no further extended context structures to examine.

This approach is somewhat similar to that taken by ARM to save VFP &
other context at the end of struct ucontext.

Userland can determine whether extended context is present by checking
for the USED_EXTCONTEXT bit in the sc_used_math field of struct
sigcontext. Whilst this could potentially change the historic semantics
of sc_used_math if further extended context which does not imply FP
context were to be introduced in the future, I have been unable to find
any userland code making use of sc_used_math at all. Using one of the
fields described as unused in struct sigcontext was considered, but the
kernel does not already write to those fields so there would be no
guarantee of the field being clear on older kernels. Other alternatives
would be to have userland check the kernel version, or to have a HWCAP
bit indicating presence of extended context. However there is a desire
to have the context & information required to decode it be self
contained such that, for example, debuggers could decode the saved
context easily.

[ralf@linux-mips.org: Fixed conflict.]

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Matthew Fortune <matthew.fortune@imgtec.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Zubair Lutfullah Kakakhel <Zubair.Kakakhel@imgtec.com>
Cc: Alex Smith <alex@alex-smith.me.uk>
Cc: linux-kernel@vger.kernel.org
Cc: Richard Weinberger <richard@nod.at>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: Daniel Borkmann <dborkman@redhat.com>
Cc: Maciej W. Rozycki <macro@codesourcery.com>
Patchwork: https://patchwork.linux-mips.org/patch/10795/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Indicate FP mode in sigcontext sc_used_math

The sc_used_math field of struct sigcontext & its variants has
traditionally been used as a boolean value indicating only whether or
not floating point context is saved within the sigcontext. With various
supported FP modes & the ability to switch between them this information
will no longer be enough to decode the meaning of the data stored in the
sc_fpregs fields of struct sigcontext.

To make that possible 3 bits are defined within sc_used_math:

  - Bit 0 (USED_FP) represents whether FP was used, essentially
    providing the boolean flag which sc_used_math as a whole provided
    previously.

  - Bit 1 (USED_FR1) provides the value of the Status.FR bit at the time
    the FP context was saved.

  - Bit 2 (USED_HYBRID_FPRS) indicates whether the FP context was saved
    under the hybrid FPR scheme. Essentially, when set the odd singles
    are located in bits 63:32 of the preceding even indexed sc_fpregs
    element.

Any userland that tests whether the sc_used_math field is zero or
non-zero will continue to function as expected. Having said that, I
could not find any userland which uses the sc_used_math field at all.

[ralf@linux-mips.org: Fixed rejects.]

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Matthew Fortune <matthew.fortune@imgtec.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: linux-kernel@vger.kernel.org
Cc: Richard Weinberger <richard@nod.at>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Maciej W. Rozycki <macro@codesourcery.com>
Patchwork: https://patchwork.linux-mips.org/patch/10794/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Remove unused {get,put}_sigset functions

These functions are never called & thus dead code. Remove them.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Matthew Fortune <matthew.fortune@imgtec.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: linux-kernel@vger.kernel.org
Cc: Richard Weinberger <richard@nod.at>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andrew Morton <akpm@linux-foundation.org>
Patchwork: https://patchwork.linux-mips.org/patch/10793/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Use common FP sigcontext code for O32 compat

Make use of the common FP sigcontext code for O32 binaries running on
MIPS64 kernels now that it is taking appropriate offsets into struct
sigcontext(32) from struct mips_abi.

[ralf@linux-mips.org: Fixed reject.]

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Matthew Fortune <matthew.fortune@imgtec.com>
Cc: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: linux-kernel@vger.kernel.org
Cc: Richard Weinberger <richard@nod.at>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: Manuel Lauss <manuel.lauss@gmail.com>
Cc: Maciej W. Rozycki <macro@codesourcery.com>
Patchwork: https://patchwork.linux-mips.org/patch/10792/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Skip odd double FP registers when copying FP32 sigcontext

When a task uses 32 bit floating point, the odd indexed 32b register
values are stored in bits 63:32 of the preceding even indexed 64b
FP register field in saved context. Thus there is no point in
preserving the odd indexed 64b register fields since they hold no
valid context. This patch will cause them to be skipped, as is
already done in arch/mips/kernel/signal32.c.

[ralf@linux-mips.org: Fixed reject.]

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Matthew Fortune <matthew.fortune@imgtec.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: linux-kernel@vger.kernel.org
Cc: Richard Weinberger <richard@nod.at>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Maciej W. Rozycki <macro@codesourcery.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Patchwork: https://patchwork.linux-mips.org/patch/10791/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Move FP usage checks into protected_{save, restore}_fp_context

In preparation for sharing protected_{save,restore}_fp_context with
compat ABIs, move the FP usage checks into said functions. This will
both enable that code to be shared, and allow for extensions of it in
further patches to also be shared.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Matthew Fortune <matthew.fortune@imgtec.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: linux-kernel@vger.kernel.org
Cc: Richard Weinberger <richard@nod.at>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Maciej W. Rozycki <macro@codesourcery.com>
Patchwork: https://patchwork.linux-mips.org/patch/10790/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Use struct mips_abi offsets to save FP context

When saving FP state to struct sigcontext, make use of the offsets
provided by struct mips_abi to obtain appropriate addresses for the
sc_fpregs & sc_fpc_csr fields of the sigcontext. This is done only for
the native struct sigcontext in this patch (ie. for O32 in CONFIG_32BIT
kernels or for N64 in CONFIG_64BIT kernels) but is done in preparation
for sharing this code with compat ABIs in further patches.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Matthew Fortune <matthew.fortune@imgtec.com>
Cc: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Cc: linux-kernel@vger.kernel.org
Cc: Richard Weinberger <richard@nod.at>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: Manuel Lauss <manuel.lauss@gmail.com>
Cc: Maciej W. Rozycki <macro@codesourcery.com>
Patchwork: https://patchwork.linux-mips.org/patch/10789/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Add offsets to sigcontext FP fields to struct mips_abi

Add fields to struct mips_abi, which holds information regarding the
kernel-userland ABI regarding signals, to specify the offsets to the FP
related fields within the appropriate variant of struct sigcontext.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Matthew Fortune <matthew.fortune@imgtec.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: linux-kernel@vger.kernel.org
Cc: Richard Weinberger <richard@nod.at>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Maciej W. Rozycki <macro@codesourcery.com>
Patchwork: https://patchwork.linux-mips.org/patch/10788/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Simplify EVA FP context handling code

The protected_{save,restore}_fp_context functions had effectively
different implementations for EVA. Simplify & unify the code somewhat
such that EVA configurations simply guarantee the FPU-not-owned path
through the standard code path.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Matthew Fortune <matthew.fortune@imgtec.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: linux-kernel@vger.kernel.org
Cc: Richard Weinberger <richard@nod.at>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Maciej W. Rozycki <macro@codesourcery.com>
Patchwork: https://patchwork.linux-mips.org/patch/10787/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: sni: Migrate to new 'set-state' interface

Migrate sni driver to the new 'set-state' interface provided by
clockevents core, the earlier 'set-mode' interface is marked obsolete
now.

This also enables us to implement callbacks for new states of clockevent
devices, for example: ONESHOT_STOPPED.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: linux-mips@linux-mips.org
Cc: linaro-kernel@lists.linaro.org
Cc: Thomas Gleixner <tglx@linutronix.de>
Patchwork: https://patchwork.linux-mips.org/patch/10612/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: IP27: Migrate to new 'set-state' interface

Migrate sgidriver to the new 'set-state' interface provided by
clockevents core, the earlier 'set-mode' interface is marked obsolete
now.

This also enables us to implement callbacks for new states of clockevent
devices, for example: ONESHOT_STOPPED.

We weren't doing anything in the ->set_mode() callback. So, this patch
doesn't provide any set-state callbacks.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Deng-Cheng Zhu <dengcheng.zhu@imgtec.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: linux-mips@linux-mips.org
Cc: linaro-kernel@lists.linaro.org
Cc: Thomas Gleixner <tglx@linutronix.de>
Patchwork: https://patchwork.linux-mips.org/patch/10611/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: rt3352: Migrate to new 'set-state' interface

Migrate ralink driver to the new 'set-state' interface provided by
clockevents core, the earlier 'set-mode' interface is marked obsolete
now.

This also enables us to implement callbacks for new states of clockevent
devices, for example: ONESHOT_STOPPED.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: linux-mips@linux-mips.org
Cc: linaro-kernel@lists.linaro.org
Cc: Thomas Gleixner <tglx@linutronix.de>
Patchwork: https://patchwork.linux-mips.org/patch/10610/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: loongsoon32: Migrate to new 'set-state' interface

Migrate loongsoon32 driver to the new 'set-state' interface provided by
clockevents core, the earlier 'set-mode' interface is marked obsolete
now.

This also enables us to implement callbacks for new states of clockevent
devices, for example: ONESHOT_STOPPED.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Kelvin Cheung <keguang.zhang@gmail.com>
Cc: Huacai Chen <chenhc@lemote.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: linux-mips@linux-mips.org
Cc: linaro-kernel@lists.linaro.org
Cc: Thomas Gleixner <tglx@linutronix.de>
Patchwork: https://patchwork.linux-mips.org/patch/10609/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: loongson64/timer: Migrate to new 'set-state' interface

Migrate loongson driver to the new 'set-state' interface provided by
clockevents core, the earlier 'set-mode' interface is marked obsolete
now.

This also enables us to implement callbacks for new states of clockevent
devices, for example: ONESHOT_STOPPED.

[ralf@linux-mips.org: Folded in Viresh's followon fix.]

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Huacai Chen <chenhc@lemote.com>
Cc: Michael Opdenacker <michael.opdenacker@free-electrons.com>
Cc: Hongliang Tao <taohl@lemote.com>
Cc: Valentin Rothberg <valentinrothberg@gmail.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: linux-mips@linux-mips.org
Cc: linaro-kernel@lists.linaro.org
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Patchwork: https://patchwork.linux-mips.org/patch/10608/
Patchwork: https://patchwork.linux-mips.org/patch/10883/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: cevt-txx9: Migrate to new 'set-state' interface

Migrate cevt-txx9 driver to the new 'set-state' interface provided by
clockevents core, the earlier 'set-mode' interface is marked obsolete
now.

This also enables us to implement callbacks for new states of clockevent
devices, for example: ONESHOT_STOPPED.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Deng-Cheng Zhu <dengcheng.zhu@imgtec.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: linux-mips@linux-mips.org
Cc: linaro-kernel@lists.linaro.org
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Patchwork: https://patchwork.linux-mips.org/patch/10607/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: cevt-sb1250: Migrate to new 'set-state' interface

Migrate cevt-rsb1250 driver to the new 'set-state' interface provided by
clockevents core, the earlier 'set-mode' interface is marked obsolete
now.

This also enables us to implement callbacks for new states of clockevent
devices, for example: ONESHOT_STOPPED.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: linux-mips@linux-mips.org
Cc: linaro-kernel@lists.linaro.org
Cc: Thomas Gleixner <tglx@linutronix.de>
Patchwork: https://patchwork.linux-mips.org/patch/10606/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: cevt-r4k: Migrate to new 'set-state' interface

Migrate cevt-4k driver to the new 'set-state' interface provided by
clockevents core, the earlier 'set-mode' interface is marked obsolete
now.

This also enables us to implement callbacks for new states of clockevent
devices, for example: ONESHOT_STOPPED.

We weren't doing anything in the ->set_mode() callback. So, this patch
doesn't provide any set-state callbacks.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Andrew Bresticker <abrestic@chromium.org>
Cc: Qais Yousef <qais.yousef@imgtec.com>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: linux-mips@linux-mips.org
Cc: linaro-kernel@lists.linaro.org
Cc: Thomas Gleixner <tglx@linutronix.de>
Patchwork: https://patchwork.linux-mips.org/patch/10605/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: cevt-gt641xx: Migrate to new 'set-state' interface

Migrate cevt-gt641xx driver to the new 'set-state' interface provided by
clockevents core, the earlier 'set-mode' interface is marked obsolete
now.

This also enables us to implement callbacks for new states of clockevent
devices, for example: ONESHOT_STOPPED.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: linux-mips@linux-mips.org
Cc: linaro-kernel@lists.linaro.org
Cc: Thomas Gleixner <tglx@linutronix.de>
Patchwork: https://patchwork.linux-mips.org/patch/10604/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: cevt-ds1287: Migrate to new 'set-state' interface

Migrate cevt-ds1287 driver to the new 'set-state' interface provided by
clockevents core, the earlier 'set-mode' interface is marked obsolete
now.

This also enables us to implement callbacks for new states of clockevent
devices, for example: ONESHOT_STOPPED.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: linux-mips@linux-mips.org
Cc: linaro-kernel@lists.linaro.org
Cc: Thomas Gleixner <tglx@linutronix.de>
Patchwork: https://patchwork.linux-mips.org/patch/10603/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: cevt-bcm1480: Migrate to new 'set-state' interface

Migrate cevt-bcm1480 driver to the new 'set-state' interface provided by
clockevents core, the earlier 'set-mode' interface is marked obsolete
now.

This also enables us to implement callbacks for new states of clockevent
devices, for example: ONESHOT_STOPPED.

Read operation on R_SCD_TIMER_CFG and R_SCD_TIMER_INIT registers isn't
performed now for many modes as there returned values aren't used.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: linux-mips@linux-mips.org
Cc: linaro-kernel@lists.linaro.org
Cc: Thomas Gleixner <tglx@linutronix.de>
Patchwork: https://patchwork.linux-mips.org/patch/10602/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: jz4740: Migrate to new 'set-state' interface

Migrate jz4740 driver to the new 'set-state' interface provided by
clockevents core, the earlier 'set-mode' interface is marked obsolete
now.

This also enables us to implement callbacks for new states of clockevent
devices, for example: ONESHOT_STOPPED.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Deng-Cheng Zhu <dengcheng.zhu@imgtec.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: linux-mips@linux-mips.org
Cc: linaro-kernel@lists.linaro.org
Cc: Thomas Gleixner <tglx@linutronix.de>
Patchwork: https://patchwork.linux-mips.org/patch/10601/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Jazz: Migrate to new 'set-state' interface

Migrate jazz driver to the new 'set-state' interface provided by
clockevents core, the earlier 'set-mode' interface is marked obsolete
now.

This also enables us to implement callbacks for new states of clockevent
devices, for example: ONESHOT_STOPPED.

We weren't doing anything in the ->set_mode() callback. So, this patch
doesn't provide any set-state callbacks.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: linux-mips@linux-mips.org
Cc: linaro-kernel@lists.linaro.org
Cc: Thomas Gleixner <tglx@linutronix.de>
Patchwork: https://patchwork.linux-mips.org/patch/10600/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Alchemy: Migrate to new 'set-state' interface

Migrate alchemy driver to the new 'set-state' interface provided by
clockevents core, the earlier 'set-mode' interface is marked obsolete
now.

This also enables us to implement callbacks for new states of clockevent
devices, for example: ONESHOT_STOPPED.

We weren't doing anything in the ->set_mode() callback. So, this patch
doesn't provide any set-state callbacks.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Manuel Lauss <manuel.lauss@gmail.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: linux-mips@linux-mips.org
Cc: linaro-kernel@lists.linaro.org
Cc: Thomas Gleixner <tglx@linutronix.de>
Patchwork: https://patchwork.linux-mips.org/patch/10599/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Kconfig: Separate 32BIT and 64BIT config block by blank line.

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

MIPS: math-emu: Move from deprecated __initcall to arch_initcall.

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

MIPS: Lasat: Move from deprecated __initcall to arch_initcall.

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

MIPS: unaligned: Move from deprecated __initcall to arch_initcall.

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

MIPS: Sibyte: Move bus watcher from deprecated __initcall to device_initcall

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

MIPS: Rearrange ENTRYLO field definitions

The generic field definitions (i.e. present before MIPS32/MIPS64) in
mipsregs.h are conventionally not prefixed with MIPS_, so rename the
recently added MIPS_ENTRYLO_* definitions for the G, V, D, and C fields
to ENTRYLO_*. Also rearrange to put the EntryLo and EntryHi definitions
in the right place in the file.

Fixes: 8ab6abcb6aa4 ("MIPS: mipsregs.h: Add EntryLo bit definitions")
Reported-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Maciej W. Rozycki <macro@linux-mips.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10725/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: dump_tlb: Dump FrameMask register if exists

The FrameMask register is relevant to the TLB so it should be dumped by
dump_tlb_regs(), however it is only present in certain cores (r10000,
r12000, r14000, r16000). Add dumping of it, conditional upon
current_cpu_type().

Suggested-by: Joshua Kinard <kumba@gentoo.org>
Suggested-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Joshua Kinard <kumba@gentoo.org>
Cc: Maciej W. Rozycki <macro@linux-mips.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10724/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: dump_tlb: Only dump PageGrain if interesting

The PageGrain register may not exist if certain architectural features
aren't present, therefore only print out its value when dumping the TLB
registers if it is expected to contain fields relevant to the TLB.

Fixes: d1e9a4f54735 ("MIPS: Add SysRq operation to dump TLBs on all CPUs")
Reported-by: Joshua Kinard <kumba@gentoo.org>
Reported-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Joshua Kinard <kumba@gentoo.org>
Cc: Maciej W. Rozycki <macro@linux-mips.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10723/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Probe for small (1KiB) page support

Probe Config3 for small page support. This will be useful to give clues
as to whether the PageGrain register exists.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Maciej W. Rozycki <macro@linux-mips.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10722/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Refactor dumping of TLB registers for r3k/r4k

The TLB registers are dumped in a couble of places:
- sysrq_tlbdump_single() - when dumping TLB state.
- do_mcheck() - in response to a machine check error.

The main TLB registers also differ between r3k and r4k, but r4k appears
to be assumed.

Refactor this code into a dump_tlb_regs() function, implemented for both
r3k and r4k, and used by both of the above functions.

Fixes: d1e9a4f54735 ("MIPS: Add SysRq operation to dump TLBs on all CPUs")
Suggested-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Maciej W. Rozycki <macro@linux-mips.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10721/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

Documentation/sysrq.txt: Mention MIPS TLB dump (x)

Commit d1e9a4f54735 ("MIPS: Add SysRq operation to dump TLBs on all
CPUs") added the 'x' sysrq key for dumping MIPS TLB entries, but didn't
document it in Documentation/sysrq.txt.

Add mention of the MIPS use of the 'x' SysRq key.

Reported-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Acked-by: Jonathan Corbet <corbet@lwn.net>
Cc: Maciej W. Rozycki <macro@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: linux-doc@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/10720/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: math-emu: Emulate missing BC1{EQ,NE}Z instructions

Commit c8a34581ec09 ("MIPS: Emulate the BC1{EQ,NE}Z FPU instructions")
added support for emulating the new R6 BC1{EQ,NE}Z branches but it missed
the case where the instruction that caused the exception was not on a DS.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Fixes: c8a34581ec09 ("MIPS: Emulate the BC1{EQ,NE}Z FPU instructions")
Cc: <stable@vger.kernel.org> # 4.0+
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10738/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: math-emu: Allow m{f,t}hc emulation on MIPS R6

The mfhc/mthc instructions are supported on MIPS R6 so emulate
them if needed.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: <stable@vger.kernel.org> # 4.0+
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10737/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: math-emu: Fix indentation

Fix indentation for the final 'else' blocks.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10735/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: cp1emu: Fix closing bracket for the d_fmt case

The double format (d_fmt) case uses an opening bracket which then
closes at the end of the word format (w_fmt). This can be rather confusing
so add the closing bracket at the end of the d_fmt case and use another one
for the w_fmt one.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10733/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Kconfig: Drop the EXPERIMENTAL tag from MIPS R6

The MIPS R6 ISA support has been part of mainline since v4.0
and it should be in a good shape nowadays so it is not an
experimental feature anymore.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10731/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Treat CP1 control registers as unsigned ints.

These are bitfields and treating them as signed values doesn't make
any sense.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Reported-by: Chris Packham <judge.packham@gmail.com>

MIPS: Use unsigned int when reading CP0 registers

Update __read_32bit_c0_register() and __read_32bit_c0_ctrl_register() to
use "unsigned int res;" instead of "int res;". There is little reason to
treat these register values as signed. They are either counters (which
by definition are unsigned) or are made up of various bit fields to be
interpreted as per the CPU datasheet.

This has come up via u-boot[1] which sync's asm/mipsregs.h with the
kernel. In u-boots case the value read from read_c0_count() is assigned
to an unsigned long [2] which triggers a sign extension and causes a
bug.

U-boot should probably be more explicit about the types used for the
timer_read_counter() API but that aside is there any reason to treat
these values as signed integers? A quick grep around the arch/mips makes
me thing that there may be some bugs lurking when read_c0_count() starts
to yield a negative value but I haven't really explored any of them.

[1] - http://lists.denx.de/pipermail/u-boot/2015-July/219086.html
[2] - http://git.denx.de/?p=u-boot.git;a=blob;f=arch/mips/cpu/time.c#l11

Signed-off-by: Chris Packham <judge.packham@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
Cc: Chris Packham <judge.packham@gmail.com>
Cc: Steven J. Hill <Steven.Hill@imgtec.com>
Cc: Maciej W. Rozycki <macro@linux-mips.org>
Cc: linux-kernel@vger.kernel.org
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Patchwork: https://patchwork.linux-mips.org/patch/10718/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: malta: Use generic platform_maar_init

The default implementation of platform_maar_init is sufficient for Malta
boards where we want to allow speculation in the regions of memory
corresponding to DDR & disallow it elsewhere. Drop the custom
implementation such that the default is used, reducing the duplication
of information provided by the Malta platform code.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Patchwork: https://patchwork.linux-mips.org/patch/10677/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: mm: default platform_maar_init using bootmem data

Introduce a default weak implementation of platform_maar_init which
makes use of the data that platforms already provide to the bootmem
allocator. This should hopefully cover the most common configurations,
reduce the duplication of information provided by platforms & leaves
platforms with the option of providing a custom implementation if
required.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Steven J. Hill <Steven.Hill@imgtec.com>
Cc: linux-kernel@vger.kernel.org
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Patchwork: https://patchwork.linux-mips.org/patch/10676/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: MSA unaligned memory access support

The MSA architecture specification allows for hardware to not implement
unaligned vector memory accesses in some or all cases. A typical example
of this is the I6400 core which does not implement unaligned vector
memory access when the memory crosses a page boundary. The architecture
also requires that such memory accesses complete successfully as far as
userland is concerned, so the kernel is required to emulate them.

This patch implements support for emulating unaligned MSA ld & st
instructions by copying between the user memory & the tasks FP context
in struct thread_struct, updating hardware registers from there as
appropriate in order to avoid saving & restoring the entire vector
context for each unaligned memory access.

Tested both using an I6400 CPU and with a QEMU build hacked to produce
AdEL exceptions for unaligned vector memory accesses.

[paul.burton@imgtec.com:
  - Remove #ifdef's
  - Move msa_op into enum major_op rather than #define
  - Replace msa_{to,from}_wd with {read,write}_msa_wr_{b,h,w,l} and the
    format-agnostic wrappers, removing the custom endian mangling for
    big endian systems.
  - Restructure the msa_op case in emulate_load_store_insn to share
    more code between the load & store cases.
  - Avoid the need for a temporary union fpureg on the stack by simply
    reusing the already suitably aligned context in struct
    thread_struct.
  - Use sizeof(*fpr) rather than hardcoding 16 as the size for user
    memory checks & copies.
  - Stop recalculating the address of the unaligned vector memory access
    and rely upon the value read from BadVAddr as we do for other
    unaligned memory access instructions.
  - Drop the now unused val8 & val16 fields in union fpureg.
  - Rewrite commit message.
  - General formatting cleanups.]

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Cc: Huacai Chen <chenhc@lemote.com>
Cc: Maciej W. Rozycki <macro@linux-mips.org>
Cc: linux-kernel@vger.kernel.org
Cc: Jie Chen <chenj@lemote.com>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Patchwork: https://patchwork.linux-mips.org/patch/10573/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Introduce accessors for MSA vector registers

Introduce accessor functions allowing the kernel to access arbitrary
vector registers using an arbitrary data format. The accessors are
implemented in assembly, using macros to avoid massive duplication, in
order to make use of the existing support for MSA with & without
toolchain support. The accessors will be used in a later patch.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Cc: linux-kernel@vger.kernel.org
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: Manuel Lauss <manuel.lauss@gmail.com>
Patchwork: https://patchwork.linux-mips.org/patch/10572/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Declare MSA MI10 instruction formats

Declare a struct describing the MSA MI10 instruction format used for ld &
st instructions, for use by subsequent patches.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Cc: Steven J. Hill <Steven.Hill@imgtec.com>
Cc: linux-kernel@vger.kernel.org
Cc: Markos Chandras <markos.chandras@imgtec.com>
Patchwork: https://patchwork.linux-mips.org/patch/10571/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Remove "__weak" definition from arch-specific linkage.h

"__weak" is defined in include/linux/compiler-gcc.h. We shouldn't need an
arch-specific definition.

Remove the "__weak" definition from arch/mips/include/asm/linkage.h.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Cc: Andrew Bresticker <abrestic@chromium.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10689/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Remove "weak" from mips_cdmm_phys_base() declaration

Weak header file declarations are error-prone because they make every
definition weak, and the linker chooses one based on link order (see
10629d711ed7 ("PCI: Remove __weak annotation from pcibios_get_phb_of_node
decl")).

mips_cdmm_phys_base() is defined only in arch/mips/mti-malta/malta-memory.c
so there's no problem with multiple definitions. But it works better to
have a weak default implementation and allow a strong function to override
it. Then we don't have to test whether a definition is present, and if
there are ever multiple strong definitions, we get a link error instead of
calling a random definition.

Add a weak mips_cdmm_phys_base() definition and remove the weak annotation
from the declaration in arch/mips/include/asm/cdmm.h.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Cc: Andrew Bresticker <abrestic@chromium.org>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/10688/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Remove "weak" from get_c0_fdc_int() declaration

Weak header file declarations are error-prone because they make every
definition weak, and the linker chooses one based on link order (see
10629d711ed7 ("PCI: Remove __weak annotation from pcibios_get_phb_of_node
decl")).

The most elegant solution is to have a weak default implementation and
allow a strong function to override it. Then we don't have to test
whether a definition is present, and if there are ever multiple strong
definitions, we get a link error instead of calling a random definition.

Add a weak get_c0_fdc_int() definition with the default code and remove the
weak annotation from the declaration.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Cc: Andrew Bresticker <abrestic@chromium.org>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/10687/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Remove "weak" from get_c0_compare_int() declaration

Weak header file declarations are error-prone because they make every
definition weak, and the linker chooses one based on link order (see
10629d711ed7 ("PCI: Remove __weak annotation from pcibios_get_phb_of_node
decl")).

get_c0_compare_int() is defined in several files.  Each definition is weak,
so I assume Kconfig prevents two or more from being included.  The caller
contains default code used when get_c0_compare_int() isn't defined at all.

Add a weak get_c0_compare_int() definition with the default code and remove
the weak annotation from the declaration.

Then the platform implementations will be strong and will override the weak
default.  If multiple platforms are ever configured in, we'll get a link
error instead of calling a random platform's implementation.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Cc: Andrew Bresticker <abrestic@chromium.org>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/10686/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: MT: Remove "weak" from vpe_run() declaration

Weak header file declarations are error-prone because they make every
definition weak, and the linker chooses one based on link order (see
10629d711ed7 ("PCI: Remove __weak annotation from pcibios_get_phb_of_node
decl")).

That's not a problem for vpe_run() because Kconfig ensures there's never
more than one definition:

  - vpe_run() is defined in arch/mips/kernel/vpe-mt.c if
    CONFIG_MIPS_VPE_LOADER_MT=y

  - vpe_run() is defined in arch/mips/mti-malta/malta-amon.c if
    CONFIG_MIPS_CMP=y

  - CONFIG_MIPS_VPE_LOADER_MT cannot be set if CONFIG_MIPS_CMP=y

But it's simpler to verify correctness if we remove "weak" from the picture
and test the config symbols directly.

Remove "weak" from the vpe_run() declaration and use #if to test whether a
definition should be present.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Andrew Bresticker <abrestic@chromium.org>
Cc: linux-mips@linux-mips.org
Cc: James Hogan <james.hogan@imgtec.com>
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/10684/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: VPE: Exit vpe_release() early if vpe_run() isn't defined

vpe_run() is a weak symbol. If there's no definition of it, its value is
zero.

If vpe_run is zero, return failure early. We're going to fail anyway, so
there's no point in getting a VPE and attempting to load it.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Andrew Bresticker <abrestic@chromium.org>
Cc: linux-mips@linux-mips.org
Cc: James Hogan <james.hogan@imgtec.com>
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/10683/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Remove "weak" from platform_maar_init() declaration

Weak header file declarations are error-prone because they make every
definition weak, and the linker chooses one based on link order (see
10629d711ed7 ("PCI: Remove __weak annotation from pcibios_get_phb_of_node
decl")).

platform_maar_init() is defined in:

  - arch/mips/mm/init.c (where it is marked "weak")
  - arch/mips/mti-malta/malta-memory.c (without annotation)

The "weak" attribute on the platform_maar_init() extern declaration applies
to the platform-specific definition in arch/mips/mti-malta/malta-memory.c,
so both definitions are weak, and which one we get depends on link order.

Remove the "weak" attribute from the declaration.  That makes the malta
definition strong, so it will always be preferred if it is present.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
CC: linux-mips@linux-mips.org
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Cc: Andrew Bresticker <abrestic@chromium.org>
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/10682/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: CPC: Remove "weak" from mips_cpc_phys_base() and make it static

There's only one implementation of mips_cpc_phys_base(), and it's only used
within the same file, so it doesn't need to be weak, and it doesn't need an
extern declaration.

Remove the extern mips_cpc_phys_base() declaration and make it static.

[ralf@linux-mips.org: Fixed conflict.]

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
CC: linux-mips@linux-mips.org
Cc: Andrew Bresticker <abrestic@chromium.org>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/10681/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Drop CONFIG_RUNTIME_DEBUG & debug.h

The debug.h header provided some MIPS-specific debug macros, which are
no longer used at all. Remove them.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/10693/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: ops-emma2rh: Drop nonsensical db_assert

The db_assert call checks whether the bus_num pointer is non-NULL, but
does so after said pointer has been dereferenced by the assignment on
the previous line. Thus the check is pointless & likely to have been
optimised out by the compiler anyway. The check_args function is static
& only ever called from the local file with bus_num being a pointer to
an on-stack variable, so the check seems somewhat overzealous anyway.
Simply remove it.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/10692/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: rt3883: Prepare rt3883_pci_irq_handler for irq argument removal

The irq argument of most interrupt flow handlers is unused or merily
used instead of a local variable. The handlers which need the irq
argument can retrieve the irq number from the irq descriptor.

Search and update was done with coccinelle and the invaluable help of
Julia Lawall.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Julia Lawall <Julia.Lawall@lip6.fr>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: linux-mips@linux-mips.org
Cc: LKML <linux-kernel@vger.kernel.org>
Patchwork: https://patchwork.linux-mips.org/patch/10706/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: netlogic: Prepare ipi handlers for irq argument removal

The irq argument of most interrupt flow handlers is unused or merily
used instead of a local variable. The handlers which need the irq
argument can retrieve the irq number from the irq descriptor.

Search and update was done with coccinelle and the invaluable help of
Julia Lawall.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Julia Lawall <Julia.Lawall@lip6.fr>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: linux-mips@linux-mips.org
Cc: LKML <linux-kernel@vger.kernel.org>
Patchwork: https://patchwork.linux-mips.org/patch/10705/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: octeon: Replace the homebrewn flow handler

The gpio interrupt handling of octeon contains a homebrewn flow
handler which calls either handle_level_irq or handle_edge_irq
depending on the trigger type. Thats an extra conditional and call in
the interrupt handling path. The proper way to handle different types
and therefor different flows is to update the handler in the
irq_set_type() callback.

Remove the extra indirection and add the handler update to
octeon_irq_ciu_gpio_set_type(). At mapping time it defaults to
handle_level_irq which gets updated if the device tree contains a
different trigger type.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: David Daney <david.daney@cavium.com>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: linux-mips@linux-mips.org
Cc: LKML <linux-kernel@vger.kernel.org>
Patchwork: https://patchwork.linux-mips.org/patch/10704/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: ath91: Remove pointless irqdisable/enable

The various interrupt flow handlers in ath79 are cascading interrupt
handlers. They all have a disable_irq_nosync()/enable_irq() pair
around the generic_handle_irq() call. The value of this disable/enable
is zero because its a complete noop:

disable_irq_nosync() merily increments the disable count without
actually masking the interrupt. enable_irq() soleley decrements the
disable count without touching the interrupt chip. The interrupt
cannot arrive again because the complete call chain runs with
interrupts disabled.

Remove it.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mips@linux-mips.org
Cc: LKML <linux-kernel@vger.kernel.org>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Patchwork: https://patchwork.linux-mips.org/patch/10703/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: alchemy: Remove pointless irqdisable/enable

bcsr_csc_handler() is a cascading interrupt handler. It has a
disable_irq_nosync()/enable_irq() pair around the generic_handle_irq()
call. The value of this disable/enable is zero because its a complete
noop:

disable_irq_nosync() merily increments the disable count without
actually masking the interrupt. enable_irq() soleley decrements the
disable count without touching the interrupt chip. The interrupt
cannot arrive again because the complete call chain runs with
interrupts disabled.

Remove it.

[ralf@linux-mips.org: Fold in followup fix from Thomas Gleixner.]

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mips@linux-mips.org
Cc: LKML <linux-kernel@vger.kernel.org>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Patchwork: https://patchwork.linux-mips.org/patch/10702/
Patchwork: https://patchwork.linux-mips.org/patch/10708/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: bcm63xx: Use irq_set_handler_locked()

Use irq_set_handler_locked() as it avoids a redundant lookup of the
irq descriptor.

Search and replacement was done with coccinelle.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Julia Lawall <julia.lawall@lip6.fr>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: LKML <linux-kernel@vger.kernel.org>
Patchwork: https://patchwork.linux-mips.org/patch/10701/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: alchemy: Use irq_set_chip_handler_name_locked()

Hand in irq_data and avoid the redundant lookup of irq_desc.

Originally-from: Jiang Liu <jiang.liu@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: LKML <linux-kernel@vger.kernel.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10700/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: irq: Use access helper irq_data_get_affinity_mask()

This is a preparatory patch for moving irq_data struct members.

Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mips@linux-mips.org
Cc: LKML <linux-kernel@vger.kernel.org>
Patchwork: https://patchwork.linux-mips.org/patch/10699/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: pci-rt3883: Consolidate chained IRQ handler install/remove

Chained irq handlers usually set up handler data as well. We now have
a function to set both under irq_desc->lock. Replace the two calls
with one.

Search and conversion was done with coccinelle.

Reported-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Julia Lawall <Julia.Lawall@lip6.fr>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: LKML <linux-kernel@vger.kernel.org>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Patchwork: https://patchwork.linux-mips.org/patch/10698/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: pci-ar724x: Consolidate chained IRQ handler install/remove

Chained irq handlers usually set up handler data as well. We now have
a function to set both under irq_desc->lock. Replace the two calls
with one.

Search and conversion was done with coccinelle.

Reported-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Julia Lawall <Julia.Lawall@lip6.fr>
Cc: linux-mips@linux-mips.org
Cc: LKML <linux-kernel@vger.kernel.org>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Patchwork: https://patchwork.linux-mips.org/patch/10697/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: pci-ar71xx: Consolidate chained IRQ handler install/remove

Chained irq handlers usually set up handler data as well. We now have
a function to set both under irq_desc->lock. Replace the two calls
with one.

Search and conversion was done with coccinelle.

Reported-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Julia Lawall <Julia.Lawall@lip6.fr>
Cc: linux-mips@linux-mips.org
Cc: LKML <linux-kernel@vger.kernel.org>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Patchwork: https://patchwork.linux-mips.org/patch/10696/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: jz4740: Consolidate chained IRQ handler install/remove

Chained irq handlers usually set up handler data as well. We now have
a function to set both under irq_desc->lock. Replace the two calls
with one.

Search and conversion was done with coccinelle.

Reported-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Julia Lawall <Julia.Lawall@lip6.fr>
Cc: linux-mips@linux-mips.org
Cc: LKML <linux-kernel@vger.kernel.org>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Patchwork: https://patchwork.linux-mips.org/patch/10695/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Set up FTLB probability for I6400

Set up the I6400 FTLB probability similar to P5600 and proAptiv.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10652/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: cpu-probe: Fix VTLB/FTLB configuration for R6

R6 has dropped the MMUExtDef field from the config4 register and it
now returns 0. However, the return value means nothing in that case
and the only supported configuration for R6 is the VTLB+FTLB
(MMUextDef == 3). As a result, rework the code so that the correct
value is set for R6 cores.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10651/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Add default case for the FTLB enable/disable code

Add a default case for the FTLB enable/disable code. This will be used
to detect that something went wrong in the set_ftlb_enable() function
either because that function knows nothing about the running core, or
simply because the core can't turn its FTLB on/off.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10650/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: cpu-probe: Remove cp0 hazard barrier when enabling the FTLB

We are so early in the boot process where we really don't want to
stall and wait for CP0 FTLB related changes become visible so just drop
the cp0 hazard barrier.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10649/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

IRQCHIP: irq-mips-gic: Add support for CM3 64-bit timer irqs

CM3 uses a 64-bit counter and compare registers so add support for
them in the GIC counter interrupt.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Andrew Bresticker <abrestic@chromium.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10648/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

IRQCHIP: irq-mips-gic: Extend GIC accessors for 64-bit CMs

Previously, the GIC accessors were only accessing u32 registers but
newer CMs may actually be 64-bit on MIPS64 cores. As a result of which,
extended these accessors to support 64-bit reads and writes.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Andrew Bresticker <abrestic@chromium.org>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10709/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: CM: Add support for reporting CM cache errors

The CM cache error reporting code is not Malta specific and as such it
should live in the mips-cm.c file. Moreover, CM2 and CM3 differ in the
way cache errors are being recorded to the registers so extend the
previous code to add support for the CM3 as well.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10646/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: CPC: Fix type for GCR CPC base reg for 64-bit

The GCR CPC base register is 64-bit on 64-bit processors so use the
appropriate field.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10645/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: CM: The CMGCRBase register is 64-bit on 64 bit kernels.

The CMGCRBase register (CP0, 15, 3) register is 64-bit on MIPS64
so we change its type to unsigned long.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10644/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: mips-cm: Extend CM accessors for 64-bit CPUs

Previously, the CM accessors were only accessing CM registers as u32
types instead of using the native CM register with. However, newer CMs
may actually be 64-bit on MIPS64 cores. Fortunately, current 64-bit CMs
(CM3) hold all the useful configuration bits in the lower half of the
64-bit registers (at least most of them) so they can still be accessed
using the current 32-bit accessors.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Andrew Bresticker <abrestic@chromium.org>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10707/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Add platform callback before initializing the L2 cache

Allow platforms to perform platform-specific steps before configuring
the L2 cache. This is necessary for platforms with CM3 since the L2
parameters no longer live in the Config2 register.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10642/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: CM3: Add support for CM3 L2 cache.

Detect the L2 cache configuration from GCR_L2_CONFIG when a CM3 is
present in the system, rather than from Config2 which does not expose
the L2 configuration on I6400.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10641/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: CM: Add GCR_L2_CONFIG register accessors

Provide accessor functions for the GCR_L2_CONFIG register introduced
with CM3, and define the bits included in the register.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10639/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: mips-cm: Implement mips_cm_revision

Provide a function to trivially return the version of the CM present in
the system, or 0 if no CM is present. The mips_cm_revision() will be
used later on to determine the CM register width, so it must not use
the regular CM accessors to read the revision register since that will
lead to build failures due to recursive inlines.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10655/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Kconfig: Disable MIPS MT and SMP implementations for R6

R6 does not support the MIPS MT ASE and the CMP/SMP options so
restrict them in order to prevent users from selecting incompatible
SMP configuration for R6 cores. We also disable the CPS/SMP option
because its support hasn't been added to the CPS code yet.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10637/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Add MIPS I6400 probe support

Add a case in cpu_probe_mips for the MIPS I6400 processor ID, which sets
the CPU type to the new CPU_I6400.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10636/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Add cases for CPU_I6400

Add a CPU_I6400 case to various switch statements, doing the same thing
as for CPU_P5600.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10635/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Add MIPS I6400 PRid and cputype identifiers

Add a Processor ID and CPU type for the MIPS I6400 core.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10634/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: ath79: irq: IRQCHIP_DECLARE moved to linux/irqchip.h

Remove the ugly cross tree include now that IRQCHIP_DECLARE moved to
linux/irqchip.h.

Signed-off-by: Alban Bedel <albeu@free.fr>
Cc: linux-mips@linux-mips.org
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrew Bresticker <abrestic@chromium.org>
Cc: Qais Yousef <qais.yousef@imgtec.com>
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/10633/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

Merge tag 'scsi-fixes' of git://git./linux/kernel/git/jejb/scsi

Pull SCSI fixes from James Bottomley:
"A couple of major (hang and deadlock) fixes with fortunately fairly
  rare triggering conditions.  The PM oops is only really triggered by
  people using enclosure services (rare) and the fnic driver is mostly
  used in enterprise environments"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  SCSI: Fix NULL pointer dereference in runtime PM
  fnic: Use the local variable instead of I/O flag to acquire io_req_lock in fnic_queuecommand() to avoid deadloack

Merge branch 'upstream' of git://git.linux-mips.org/ralf/upstream-linus

Pull MIPS bug fixes from Ralf Baechle:
"Two more fixes for 4.2.

  One fixes a build issue with the LLVM assembler - LLVM assembler macro
  names are case sensitive, GNU as macro names are insensitive; the
  other corrects a license string (GPL v2, not GPLv2) such that the
  module loader will recognice the license correctly"

* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus:
  FIRMWARE: bcm47xx_nvram: Fix module license.
  MIPS: Fix LLVM build issue.

Merge branch 'for-linus' of git://git./linux/kernel/git/viro/vfs

Pull 9p regression fix from Al Viro:
"Fix for breakage introduced when switching p9_client_{read,write}() to
struct iov_iter * (went into 4.1)"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
9p: ensure err is initialized to 0 in p9_client_read/write

9p: ensure err is initialized to 0 in p9_client_read/write

Some use of those functions were providing unitialized values to those
functions. Notably, when reading 0 bytes from an empty file on a 9P
filesystem, the return code of read() was not 0.

Tested with this simple program:

    #include <assert.h>
    #include <sys/types.h>
    #include <sys/stat.h>
    #include <fcntl.h>
    #include <unistd.h>

    int main(int argc, const char **argv)
    {
        assert(argc == 2);
        char buffer[256];
        int fd = open(argv[1], O_RDONLY|O_NOCTTY);
        assert(fd >= 0);
        assert(read(fd, buffer, 0) == 0);
        return 0;
    }

Cc: stable@vger.kernel.org # v4.1
Signed-off-by: Vincent Bernat <vincent@bernat.im>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Merge branch 'fixes' of git://ftp.arm.linux.org.uk/~rmk/linux-arm

Pull ARM fixes from Russell King:
"Another couple of small ARM fixes.

  A patch from Masahiro Yamada who noticed that "make -jN all zImage"
  would end up generating bad images where N > 1, and a patch from
  Nicolas to fix the Marvell CPU user access optimisation code when page
  faults are disabled"

* 'fixes' of git://ftp.arm.linux.org.uk/~rmk/linux-arm:
  ARM: 8418/1: add boot image dependencies to not generate invalid images
  ARM: 8414/1: __copy_to_user_memcpy: fix mmap semaphore usage

Merge branch 'x86-urgent-for-linus' of git://git./linux/kernel/git/tip/tip

Pull x86 fixes from Ingo Molnar:
"Various low level fixes: fix more fallout from the FPU rework and the
  asm entry code rework, plus an MSI rework fix, and an idle-tracing fix"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/fpu/math-emu: Fix crash in fork()
  x86/fpu/math-emu: Fix math-emu boot crash
  x86/idle: Restore trace_cpu_idle to mwait_idle() calls
  x86/irq: Build correct vector mapping for multiple MSI interrupts
  Revert "sched/x86_64: Don't save flags on context switch"

Merge branch 'perf-urgent-for-linus' of git://git./linux/kernel/git/tip/tip

Pull perf fixes from Ingo Molnar:
"Tooling fixes: a 'perf record' deadlock fix plus debuggability fixes"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf top: Show backtrace when handling a SIGSEGV on --stdio mode
  perf tools: Fix buildid processing
  perf tools: Make fork event processing more resilient
  perf tools: Avoid deadlock when map_groups are broken

Merge branch 'irq-urgent-for-linus' of git://git./linux/kernel/git/tip/tip

Pull irq fixes from Thomas Gleixner:
"A series of small fixlets for a regression visible on OMAP devices
  caused by the conversion of the OMAP interrupt chips to hierarchical
  interrupt domains.  Mostly one liners on the driver side plus a small
  helper function in the core to avoid open coded mess in the drivers"

* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  irqchip/crossbar: Restore set_wake functionality
  irqchip/crossbar: Restore the mask on suspend behaviour
  ARM: OMAP: wakeupgen: Restore the irq_set_type() mechanism
  irqchip/crossbar: Restore the irq_set_type() mechanism
  genirq: Introduce irq_chip_set_type_parent() helper
  genirq: Don't return ENOSYS in irq_chip_retrigger_hierarchy

Merge branch 'timers-urgent-for-linus' of git://git./linux/kernel/git/tip/tip

Pull timer fixes from Thomas Gleixner:
"Two minimalistic fixes for 4.2 regressions:

   - Eric fixed a thinko in the timer_list base switching code caused by
     the overhaul of the timer wheel.  It can cause a cpu to see the
     wrong base for a timer while we move the timer around.

   - Guenter fixed a regression for IMX if booted w/o device tree, where
     the timer interrupt is not initialized and therefor the machine
     fails to boot"

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  clocksource/imx: Fix boot with non-DT systems
  timer: Write timer->flags atomically

x86/fpu/math-emu: Fix crash in fork()

During later stages of math-emu bootup the following crash triggers:

math_emulate: 0060:c100d0a8
Kernel panic - not syncing: Math emulation needed in kernel
CPU: 0 PID: 1511 Comm: login Not tainted 4.2.0-rc7+ #1012
[...]
Call Trace:
  [<c181d50d>] dump_stack+0x41/0x52
  [<c181c918>] panic+0x77/0x189
  [<c1003530>] ? math_error+0x140/0x140
  [<c164c2d7>] math_emulate+0xba7/0xbd0
  [<c100d0a8>] ? fpu__copy+0x138/0x1c0
  [<c1109c3c>] ? __alloc_pages_nodemask+0x12c/0x870
  [<c136ac20>] ? proc_clear_tty+0x40/0x70
  [<c136ac6e>] ? session_clear_tty+0x1e/0x30
  [<c1003530>] ? math_error+0x140/0x140
  [<c1003575>] do_device_not_available+0x45/0x70
  [<c100d0a8>] ? fpu__copy+0x138/0x1c0
  [<c18258e6>] error_code+0x5a/0x60
  [<c1003530>] ? math_error+0x140/0x140
  [<c100d0a8>] ? fpu__copy+0x138/0x1c0
  [<c100c205>] arch_dup_task_struct+0x25/0x30
  [<c1048cea>] copy_process.part.51+0xea/0x1480
  [<c115a8e5>] ? dput+0x175/0x200
  [<c136af70>] ? no_tty+0x30/0x30
  [<c1157242>] ? do_vfs_ioctl+0x322/0x540
  [<c104a21a>] _do_fork+0xca/0x340
  [<c1057b06>] ? SyS_rt_sigaction+0x66/0x90
  [<c104a557>] SyS_clone+0x27/0x30
  [<c1824a80>] sysenter_do_call+0x12/0x12

The reason is the incorrect assumption in fpu_copy(), that FNSAVE
can be executed from math-emu kernels as well.

Don't try to copy the registers, the soft state will be copied
by fork anyway, so the child task inherits the parent task's
soft math state.

With this fix applied math-emu kernels boot up fine on modern
hardware and the 'no387 nofxsr' boot options.

Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Bobby Powers <bobbypowers@gmail.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/fpu/math-emu: Fix math-emu boot crash

On a math-emu bootup the following crash occurs:

Initializing CPU#0
------------[ cut here ]------------
kernel BUG at arch/x86/kernel/traps.c:779!
invalid opcode: 0000 [#1] SMP
[...]
EIP is at do_device_not_available+0xe/0x70
[...]
Call Trace:
[<c18238e6>] error_code+0x5a/0x60
[<c1002bd0>] ? math_error+0x140/0x140
[<c100bbd9>] ? fpu__init_cpu+0x59/0xa0
[<c1012322>] cpu_init+0x202/0x330
[<c104509f>] ? __native_set_fixmap+0x1f/0x30
[<c1b56ab0>] trap_init+0x305/0x346
[<c1b548af>] start_kernel+0x1a5/0x35d
[<c1b542b4>] i386_start_kernel+0x82/0x86

The reason is that in the following commit:

b1276c48e91b ("x86/fpu: Initialize fpregs in fpu__init_cpu_generic()")

I failed to consider math-emu's limitation that it cannot execute the
FNINIT instruction in kernel mode.

The long term fix might be to allow math-emu to execute (certain) kernel
mode FPU instructions, but for now apply the safe (albeit somewhat ugly)
fix: initialize the emulation state explicitly without trapping out to
the FPU emulator.

Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>