Now that the GIC properly uses IRQ domains, kill off the per-platform
routing tables that were used to make the GIC appear transparent.

This includes:
 - removing the mapping tables and the support for applying them,
 - moving GIC IPI support to the GIC driver,
 - properly routing the i8259 through the GIC on Malta, and
 - updating IRQ assignments on SEAD-3 when the GIC is present.

Platforms no longer will pass an interrupt mapping table to gic_init.
Instead, they will pass the CPU interrupt vector (2 - 7) that they
expect the GIC to route interrupts to.  Note that in EIC mode this
value is ignored and all GIC interrupts are routed to EIC vector 1.
Signed-off-by: NAndrew Bresticker <abrestic@chromium.org>
Acked-by: NJason Cooper <jason@lakedaemon.net>
Reviewed-by: NQais Yousef <qais.yousef@imgtec.com>
Tested-by: NQais Yousef <qais.yousef@imgtec.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jeffrey Deans <jeffrey.deans@imgtec.com>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Jonas Gorski <jogo@openwrt.org>
Cc: John Crispin <blogic@openwrt.org>
Cc: David Daney <ddaney.cavm@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/7816/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Use a simple IRQ domain for the MIPS GIC.  Remove the gic_platform_init
callback as it's no longer necessary for it to set the irqchip.
Signed-off-by: NAndrew Bresticker <abrestic@chromium.org>
Acked-by: NJason Cooper <jason@lakedaemon.net>
Reviewed-by: NQais Yousef <qais.yousef@imgtec.com>
Tested-by: NQais Yousef <qais.yousef@imgtec.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jeffrey Deans <jeffrey.deans@imgtec.com>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Jonas Gorski <jogo@openwrt.org>
Cc: John Crispin <blogic@openwrt.org>
Cc: David Daney <ddaney.cavm@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/7811/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

If the online CPU check in gic_set_affinity() fails, return a proper
errno value instead of -1.
Signed-off-by: NAndrew Bresticker <abrestic@chromium.org>
Acked-by: NJason Cooper <jason@lakedaemon.net>
Reviewed-by: NQais Yousef <qais.yousef@imgtec.com>
Tested-by: NQais Yousef <qais.yousef@imgtec.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jeffrey Deans <jeffrey.deans@imgtec.com>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Jonas Gorski <jogo@openwrt.org>
Cc: John Crispin <blogic@openwrt.org>
Cc: David Daney <ddaney.cavm@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/7814/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Implement an irq_set_type callback for the GIC which is used to set
the polarity and trigger type of GIC interrupts.
Signed-off-by: NAndrew Bresticker <abrestic@chromium.org>
Acked-by: NJason Cooper <jason@lakedaemon.net>
Reviewed-by: NQais Yousef <qais.yousef@imgtec.com>
Tested-by: NQais Yousef <qais.yousef@imgtec.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jeffrey Deans <jeffrey.deans@imgtec.com>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Jonas Gorski <jogo@openwrt.org>
Cc: John Crispin <blogic@openwrt.org>
Cc: David Daney <ddaney.cavm@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/7810/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

There's no need for platforms to have their own GIC irq_ack/irq_eoi
callbacks.  irq_ack need only clear the GIC's edge detector on
edge-triggered interrupts and there's no need at all for irq_eoi.
Also get rid of the mask_ack callback since it's not necessary either.
Signed-off-by: NAndrew Bresticker <abrestic@chromium.org>
Acked-by: NJason Cooper <jason@lakedaemon.net>
Reviewed-by: NQais Yousef <qais.yousef@imgtec.com>
Tested-by: NQais Yousef <qais.yousef@imgtec.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jeffrey Deans <jeffrey.deans@imgtec.com>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Jonas Gorski <jogo@openwrt.org>
Cc: John Crispin <blogic@openwrt.org>
Cc: David Daney <ddaney.cavm@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/7809/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Move GIC irqchip support to drivers/irqchip/ and rename the Kconfig
option from IRQ_GIC to MIPS_GIC to avoid confusion with the ARM GIC.
Signed-off-by: NAndrew Bresticker <abrestic@chromium.org>
Acked-by: NJason Cooper <jason@lakedaemon.net>
Reviewed-by: NQais Yousef <qais.yousef@imgtec.com>
Tested-by: NQais Yousef <qais.yousef@imgtec.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jeffrey Deans <jeffrey.deans@imgtec.com>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Jonas Gorski <jogo@openwrt.org>
Cc: John Crispin <blogic@openwrt.org>
Cc: David Daney <ddaney.cavm@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/7812/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Define a generic MIPS_GIC_IRQ_BASE which should be suitable for all
current boards in <mach-generic/irq.h>.
Signed-off-by: NAndrew Bresticker <abrestic@chromium.org>
Reviewed-by: NQais Yousef <qais.yousef@imgtec.com>
Tested-by: NQais Yousef <qais.yousef@imgtec.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Jeffrey Deans <jeffrey.deans@imgtec.com>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Jonas Gorski <jogo@openwrt.org>
Cc: John Crispin <blogic@openwrt.org>
Cc: David Daney <ddaney.cavm@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/7808/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

The GIC on Malta boards supports a total of 47 interrupts (40 shared
and 7 local) and is assigned a base of 24.  This overlaps with the
MSC01 interrupt assignments which have a base of 64, so move the MSC01
interrupt base back a bit to give the GIC some room.
Signed-off-by: NAndrew Bresticker <abrestic@chromium.org>
Reviewed-by: NQais Yousef <qais.yousef@imgtec.com>
Tested-by: NQais Yousef <qais.yousef@imgtec.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Jeffrey Deans <jeffrey.deans@imgtec.com>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Jonas Gorski <jogo@openwrt.org>
Cc: John Crispin <blogic@openwrt.org>
Cc: David Daney <ddaney.cavm@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/7815/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

In preparation for GIC IRQ domain support, assign a GIC IRQ base
that does not overlap with the CPU IRQs.

Note that this breaks SEAD-3 when the GIC is in EIC mode, though
I'm not convinced it was working before either.  It will be fixed
in the following patches.
Signed-off-by: NAndrew Bresticker <abrestic@chromium.org>
Reviewed-by: NQais Yousef <qais.yousef@imgtec.com>
Tested-by: NQais Yousef <qais.yousef@imgtec.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Jeffrey Deans <jeffrey.deans@imgtec.com>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Jonas Gorski <jogo@openwrt.org>
Cc: John Crispin <blogic@openwrt.org>
Cc: David Daney <ddaney.cavm@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/7813/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

It's a duplicate of sead3-platform.c and is not even compiled.
Remove it before we start fixing up IRQ assignments.
Signed-off-by: NAndrew Bresticker <abrestic@chromium.org>
Reviewed-by: NQais Yousef <qais.yousef@imgtec.com>
Tested-by: NQais Yousef <qais.yousef@imgtec.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Jeffrey Deans <jeffrey.deans@imgtec.com>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Jonas Gorski <jogo@openwrt.org>
Cc: John Crispin <blogic@openwrt.org>
Cc: David Daney <ddaney.cavm@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/7807/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Nothing calls gic_{enable,disable}_interrupt() any more.
Signed-off-by: NAndrew Bresticker <abrestic@chromium.org>
Reviewed-by: NQais Yousef <qais.yousef@imgtec.com>
Tested-by: NQais Yousef <qais.yousef@imgtec.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Andrew Bresticker <abrestic@chromium.org>
Cc: Jeffrey Deans <jeffrey.deans@imgtec.com>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Qais Yousef <qais.yousef@imgtec.com>
Cc: Jonas Gorski <jogo@openwrt.org>
Cc: John Crispin <blogic@openwrt.org>
Cc: David Daney <ddaney.cavm@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/7806/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Currently interrupt vectors 2 and 5 are left disabled on secondary CPUs.
Since systems using CPS must also have a GIC, which is responsible for
routing all external interrupts and can map them to any hardware interrupt
vector, enable the remaining vectors.  The two software interrupt vectors
are left disabled since they are not used with CPS.
Signed-off-by: NAndrew Bresticker <abrestic@chromium.org>
Reviewed-by: NQais Yousef <qais.yousef@imgtec.com>
Tested-by: NQais Yousef <qais.yousef@imgtec.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Andrew Bresticker <abrestic@chromium.org>
Cc: Jeffrey Deans <jeffrey.deans@imgtec.com>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Qais Yousef <qais.yousef@imgtec.com>
Cc: Jonas Gorski <jogo@openwrt.org>
Cc: John Crispin <blogic@openwrt.org>
Cc: David Daney <ddaney.cavm@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/7803/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

The hardware perf event driver and oprofile interpret the global
cp0_perfcount_irq differently: in the hardware perf event driver
it is an offset from MIPS_CPU_IRQ_BASE and in oprofile it is the
actual IRQ number.  This still works most of the time since
MIPS_CPU_IRQ_BASE is usually 0, but is clearly wrong.  Since the
performance counter interrupt may vary from platform to platform
like the C0 timer interrupt, add the optional get_c0_perfcount_int
hook which returns the IRQ number of the performance counter.
The hook should return < 0 if the performance counter interrupt is
shared with the timer.  If the hook is not present, the CPU vector
reported in C0_IntCtl (cp0_perfcount_irq) is used.
Signed-off-by: NAndrew Bresticker <abrestic@chromium.org>
Reviewed-by: NQais Yousef <qais.yousef@imgtec.com>
Tested-by: NQais Yousef <qais.yousef@imgtec.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Andrew Bresticker <abrestic@chromium.org>
Cc: Jeffrey Deans <jeffrey.deans@imgtec.com>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Qais Yousef <qais.yousef@imgtec.com>
Cc: Jonas Gorski <jogo@openwrt.org>
Cc: John Crispin <blogic@openwrt.org>
Cc: David Daney <ddaney.cavm@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/7805/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Create a legacy IRQ domain for the 16 i8259 interrupts.
Signed-off-by: NAndrew Bresticker <abrestic@chromium.org>
Reviewed-by: NQais Yousef <qais.yousef@imgtec.com>
Tested-by: NQais Yousef <qais.yousef@imgtec.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Andrew Bresticker <abrestic@chromium.org>
Cc: Jeffrey Deans <jeffrey.deans@imgtec.com>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Qais Yousef <qais.yousef@imgtec.com>
Cc: Jonas Gorski <jogo@openwrt.org>
Cc: John Crispin <blogic@openwrt.org>
Cc: David Daney <ddaney.cavm@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/7804/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

When mapping an interrupt in the CPU IRQ domain, set the vint handler
for that interrupt if the CPU uses vectored interrupt handling.
Signed-off-by: NAndrew Bresticker <abrestic@chromium.org>
Reviewed-by: NQais Yousef <qais.yousef@imgtec.com>
Tested-by: NQais Yousef <qais.yousef@imgtec.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Andrew Bresticker <abrestic@chromium.org>
Cc: Jeffrey Deans <jeffrey.deans@imgtec.com>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Qais Yousef <qais.yousef@imgtec.com>
Cc: Jonas Gorski <jogo@openwrt.org>
Cc: John Crispin <blogic@openwrt.org>
Cc: David Daney <ddaney.cavm@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/7802/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

For platforms which boot with device-tree or have correctly chained
all external interrupt controllers, a generic plat_irq_dispatch() can
be used.  Implement a plat_irq_dispatch() which simply handles all the
pending interrupts as reported by C0_Cause.
Signed-off-by: NAndrew Bresticker <abrestic@chromium.org>
Reviewed-by: NQais Yousef <qais.yousef@imgtec.com>
Tested-by: NQais Yousef <qais.yousef@imgtec.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Andrew Bresticker <abrestic@chromium.org>
Cc: Jeffrey Deans <jeffrey.deans@imgtec.com>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Qais Yousef <qais.yousef@imgtec.com>
Cc: Jonas Gorski <jogo@openwrt.org>
Cc: John Crispin <blogic@openwrt.org>
Cc: David Daney <ddaney.cavm@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/7801/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

mips_cpu_intc_init() is used for DT-based initialization of the CPU
IRQ domain.  Give it a more appropriate name.
Signed-off-by: NAndrew Bresticker <abrestic@chromium.org>
Reviewed-by: NQais Yousef <qais.yousef@imgtec.com>
Tested-by: NQais Yousef <qais.yousef@imgtec.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Andrew Bresticker <abrestic@chromium.org>
Cc: Jeffrey Deans <jeffrey.deans@imgtec.com>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Qais Yousef <qais.yousef@imgtec.com>
Cc: Jonas Gorski <jogo@openwrt.org>
Cc: John Crispin <blogic@openwrt.org>
Cc: David Daney <ddaney.cavm@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/7800/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Use an IRQ domain for the 8 CPU IRQs in both the DT and non-DT cases.
Signed-off-by: NAndrew Bresticker <abrestic@chromium.org>
Reviewed-by: NQais Yousef <qais.yousef@imgtec.com>
Tested-by: NQais Yousef <qais.yousef@imgtec.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Andrew Bresticker <abrestic@chromium.org>
Cc: Jeffrey Deans <jeffrey.deans@imgtec.com>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Qais Yousef <qais.yousef@imgtec.com>
Cc: Jonas Gorski <jogo@openwrt.org>
Cc: John Crispin <blogic@openwrt.org>
Cc: David Daney <ddaney.cavm@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/7799/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Add new 'noftlb' kernel command line option to disable the FTLB.
Since the kernel command line is not available when probing and
enabling the CPU features in cpu_probe(), we let the kernel configure
the FTLB during the config4 decode operation and we disable the FTLB later
on, once the command line has become available to us. This should have
no negative effects since FTLB isn't used so early in the boot process.
FTLB increases the effective TLB size leading to less TLB misses. However,
sometimes it's useful to be able to disable it when debugging memory related
core features or other hardware components.
Signed-off-by: NMarkos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: http://patchwork.linux-mips.org/patch/7586/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Use the much more common pr_warn instead of pr_warning
with the goal of removing pr_warning eventually.

Other miscellanea:

o Coalesce formats
o Realign arguments
Signed-off-by: NJoe Perches <joe@perches.com>
Cc: linux-mips <linux-mips@linux-mips.org>
Cc: LKML <linux-kernel@vger.kernel.org>
Patchwork: https://patchwork.linux-mips.org/patch/7935/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Caller (generic PCI code) already do proper locking so no need to add
another one here. Local PCI read/write functions are never called
simultaneously, also they do not require synchronization with the PCI
controller ops, since they are used before the controller registration.
Signed-off-by: NSergey Ryazanov <ryazanov.s.a@gmail.com>
Cc: Linux MIPS <linux-mips@linux-mips.org>
Cc: Gabor Juhos <juhosg@openwrt.org>
Patchwork: https://patchwork.linux-mips.org/patch/7603/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Caller (generic PCI code) already do proper locking so no need to add
another one here.
Signed-off-by: NSergey Ryazanov <ryazanov.s.a@gmail.com>
Cc: Linux MIPS <linux-mips@linux-mips.org>
Cc: Gabor Juhos <juhosg@openwrt.org>
Patchwork: https://patchwork.linux-mips.org/patch/7602/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Caller (generic PCI code) already do proper locking so no need to add
another one here.
Signed-off-by: NSergey Ryazanov <ryazanov.s.a@gmail.com>
Cc: Linux MIPS <linux-mips@linux-mips.org>
Patchwork: https://patchwork.linux-mips.org/patch/7601/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Caller (generic PCI code) already do proper locking so no need to add
another one here.
Signed-off-by: NSergey Ryazanov <ryazanov.s.a@gmail.com>
Cc: Linux MIPS <linux-mips@linux-mips.org>
Patchwork: https://patchwork.linux-mips.org/patch/7600/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Currently, arch_trigger_all_cpu_backtrace() is defined in only x86 and
sparc which have an NMI.  But in case of softlockup, it could be possible
to dump backtrace of all cpus. and this could be helpful for debugging.

for example, if system has 2 cpus.

	CPU 0				CPU 1
 acquire read_lock()

				try to do write_lock()

 ,,,
 missing read_unlock()

In this case, softlockup will occur becasuse CPU 0 does not call
read_unlock().  And dump_stack() print only backtrace for "CPU 0". If
CPU1's backtrace is printed it's very helpful.

[ralf@linux-mips.org: Fixed whitespace and formatting issues.]
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/8200/

Based on the spatch

@@
expression e;
@@
- return (e);
+ return e;

with heavy hand editing because some of the changes are either whitespace
or identation only or result in excessivly long lines.
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

x86 call do_notify_resume on paranoid returns if TIF_UPROBE is set but
not on non-paranoid returns.  I suspect that this is a mistake and that
the code only works because int3 is paranoid.

Setting _TIF_NOTIFY_RESUME in the uprobe code was probably a workaround
for the x86 bug.  With that bug fixed, we can remove _TIF_NOTIFY_RESUME
from the uprobes code.
Reported-by: NOleg Nesterov <oleg@redhat.com>
Acked-by: NSrikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: NBorislav Petkov <bp@suse.de>
Signed-off-by: NAndy Lutomirski <luto@amacapital.net>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Chris bisected a NULL pointer deference in task_sched_runtime() to
commit 6e998916 'sched/cputime: Fix clock_nanosleep()/clock_gettime()
inconsistency'.

Chris observed crashes in atop or other /proc walking programs when he
started fork bombs on his machine.  He assumed that this is a new exit
race, but that does not make any sense when looking at that commit.

What's interesting is that, the commit provides update_curr callbacks
for all scheduling classes except stop_task and idle_task.

While nothing can ever hit that via the clock_nanosleep() and
clock_gettime() interfaces, which have been the target of the commit in
question, the author obviously forgot that there are other code paths
which invoke task_sched_runtime()

do_task_stat(()
 thread_group_cputime_adjusted()
   thread_group_cputime()
     task_cputime()
       task_sched_runtime()
        if (task_current(rq, p) && task_on_rq_queued(p)) {
          update_rq_clock(rq);
          up->sched_class->update_curr(rq);
        }

If the stats are read for a stomp machine task, aka 'migration/N' and
that task is current on its cpu, this will happily call the NULL pointer
of stop_task->update_curr.  Ooops.

Chris observation that this happens faster when he runs the fork bomb
makes sense as the fork bomb will kick migration threads more often so
the probability to hit the issue will increase.

Add the missing update_curr callbacks to the scheduler classes stop_task
and idle_task.  While idle tasks cannot be monitored via /proc we have
other means to hit the idle case.

Fixes: 6e998916 'sched/cputime: Fix clock_nanosleep()/clock_gettime() inconsistency'
Reported-by: NChris Mason <clm@fb.com>
Reported-and-tested-by: NBorislav Petkov <bp@alien8.de>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Merge x86-64 iret fixes from Andy Lutomirski:
 "This addresses the following issues:

   - an unrecoverable double-fault triggerable with modify_ldt.
   - invalid stack usage in espfix64 failed IRET recovery from IST
     context.
   - invalid stack usage in non-espfix64 failed IRET recovery from IST
     context.

  It also makes a good but IMO scary change: non-espfix64 failed IRET
  will now report the correct error.  Hopefully nothing depended on the
  old incorrect behavior, but maybe Wine will get confused in some
  obscure corner case"

* emailed patches from Andy Lutomirski <luto@amacapital.net>:
  x86_64, traps: Rework bad_iret
  x86_64, traps: Stop using IST for #SS
  x86_64, traps: Fix the espfix64 #DF fixup and rewrite it in C

It's possible for iretq to userspace to fail.  This can happen because
of a bad CS, SS, or RIP.

Historically, we've handled it by fixing up an exception from iretq to
land at bad_iret, which pretends that the failed iret frame was really
the hardware part of #GP(0) from userspace.  To make this work, there's
an extra fixup to fudge the gs base into a usable state.

This is suboptimal because it loses the original exception.  It's also
buggy because there's no guarantee that we were on the kernel stack to
begin with.  For example, if the failing iret happened on return from an
NMI, then we'll end up executing general_protection on the NMI stack.
This is bad for several reasons, the most immediate of which is that
general_protection, as a non-paranoid idtentry, will try to deliver
signals and/or schedule from the wrong stack.

This patch throws out bad_iret entirely.  As a replacement, it augments
the existing swapgs fudge into a full-blown iret fixup, mostly written
in C.  It's should be clearer and more correct.
Signed-off-by: NAndy Lutomirski <luto@amacapital.net>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

On a 32-bit kernel, this has no effect, since there are no IST stacks.

On a 64-bit kernel, #SS can only happen in user code, on a failed iret
to user space, a canonical violation on access via RSP or RBP, or a
genuine stack segment violation in 32-bit kernel code.  The first two
cases don't need IST, and the latter two cases are unlikely fatal bugs,
and promoting them to double faults would be fine.

This fixes a bug in which the espfix64 code mishandles a stack segment
violation.

This saves 4k of memory per CPU and a tiny bit of code.
Signed-off-by: NAndy Lutomirski <luto@amacapital.net>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There's nothing special enough about the espfix64 double fault fixup to
justify writing it in assembly.  Move it to C.

This also fixes a bug: if the double fault came from an IST stack, the
old asm code would return to a partially uninitialized stack frame.

Fixes: 3891a04aSigned-off-by: NAndy Lutomirski <luto@amacapital.net>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Pull ARM SoC fixes from Olof Johansson:
 "A collection of fixes this week:

   - A set of clock fixes for shmobile platforms
   - A fix for tegra that moves serial port labels to be per board.
     We're choosing to merge this for 3.18 because the labels will start
     being parsed in 3.19, and without this change serial port numbers
     that used to be stable since the dawn of time will change numbers.
   - A few other DT tweaks for Tegra.
   - A fix for multi_v7_defconfig that makes it stop spewing cpufreq
     errors on Arndale (Exynos)"

* tag 'armsoc-for-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc:
  ARM: multi_v7_defconfig: fix failure setting CPU voltage by enabling dependent I2C controller
  ARM: tegra: roth: Fix SD card VDD_IO regulator
  ARM: tegra: Remove eMMC vmmc property for roth/tn7
  ARM: dts: tegra: move serial aliases to per-board
  ARM: tegra: Add serial port labels to Tegra124 DT
  ARM: shmobile: kzm9g legacy: Set i2c clks_per_count to 2
  ARM: shmobile: r8a7740 dtsi: Correct IIC0 parent clock
  ARM: shmobile: r8a7790: Fix SD3CKCR address to device tree
  ARM: shmobile: r8a7740 legacy: Correct IIC0 parent clock
  ARM: shmobile: r8a7740 legacy: Add missing INTCA clock for irqpin module
  ARM: shmobile: r8a7790: Fix SD3CKCR address
  ARM: dts: sun6i: Re-parent ahb1_mux to pll6 as required by dma controller

Pull percpu fix from Tejun Heo:
 "This contains one patch to fix a race condition which can lead to
  percpu_ref using a percpu pointer which is corrupted with a set DEAD
  bit.  The bug was introduced while separating out the ATOMIC mode flag
  from the DEAD flag.  The fix is pretty straight forward.

  I just committed the patch to the percpu tree but am sending out the
  pull request early as I'll be on vacation for a week.  The patch
  should be fairly safe and while the latency will be higher I'll be
  checking emails"

* 'for-3.18-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu:
  percpu-ref: fix DEAD flag contamination of percpu pointer

Pull btrfs deadlock fix from Chris Mason:
 "This has a fix for a long standing deadlock that we've been trying to
  nail down for a while.  It ended up being a bad interaction with the
  fair reader/writer locks and the order btrfs reacquires locks in the
  btree"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
  btrfs: fix lockups from btrfs_clear_path_blocking

While decoupling ATOMIC and DEAD flags, f47ad457 ("percpu_ref:
decouple switching to percpu mode and reinit") updated
__ref_is_percpu() so that it only tests ATOMIC flag to determine
whether the ref is in percpu mode or not; however, while DEAD implies
ATOMIC, the two flags are set separately during percpu_ref_kill() and
if __ref_is_percpu() races percpu_ref_kill(), it may see DEAD w/o
ATOMIC.  Because __ref_is_percpu() returns @ref->percpu_count_ptr
value verbatim as the percpu pointer after testing ATOMIC, the pointer
may now be contaminated with the DEAD flag.

This can be fixed by clearing the flag bits before returning the
pointer which was the fix proposed by Shaohua; however, as DEAD
implies ATOMIC, we can just test for both flags at once and avoid the
explicit masking.

Update __ref_is_percpu() so that it tests that both ATOMIC and DEAD
are clear before returning @ref->percpu_count_ptr as the percpu
pointer.
Signed-off-by: NTejun Heo <tj@kernel.org>
Reported-and-Reviewed-by: NShaohua Li <shli@kernel.org>
Link: http://lkml.kernel.org/r/995deb699f5b873c45d667df4add3b06f73c2c25.1416638887.git.shli@kernel.org
Fixes: f47ad457 ("percpu_ref: decouple switching to percpu mode and reinit")

Pull timer fix from Thomas Gleixner:
 "A single bugfix for an init order problem in the sun4i subarch
  clockevents code"

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  clockevent: sun4i: Fix race condition in the probe code

Pull vfs fixes from Al Viro:
 "Assorted fixes, most in overlayfs land"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  ovl: ovl_dir_fsync() cleanup
  ovl: update MAINTAINERS
  ovl: pass dentry into ovl_dir_read_merged()
  ovl: use lockless_dereference() for upperdentry
  ovl: allow filenames with comma
  ovl: fix race in private xattr checks
  ovl: fix remove/copy-up race
  ovl: rename filesystem type to "overlay"
  isofs: avoid unused function warning
  vfs: fix reference leak in d_prune_aliases()

Pull networking fixes from David Miller:

 1) Fix BUG when decrypting empty packets in mac80211, from Ronald Wahl.

 2) nf_nat_range is not fully initialized and this is copied back to
    userspace, from Daniel Borkmann.

 3) Fix read past end of b uffer in netfilter ipset, also from Dan
    Carpenter.

 4) Signed integer overflow in ipv4 address mask creation helper
    inet_make_mask(), from Vincent BENAYOUN.

 5) VXLAN, be2net, mlx4_en, and qlcnic need ->ndo_gso_check() methods to
    properly describe the device's capabilities, from Joe Stringer.

 6) Fix memory leaks and checksum miscalculations in openvswitch, from
    Pravin B SHelar and Jesse Gross.

 7) FIB rules passes back ambiguous error code for unreachable routes,
    making behavior confusing for userspace.  Fix from Panu Matilainen.

 8) ieee802154fake_probe() doesn't release resources properly on error,
    from Alexey Khoroshilov.

 9) Fix skb_over_panic in add_grhead(), from Daniel Borkmann.

10) Fix access of stale slave pointers in bonding code, from Nikolay
    Aleksandrov.

11) Fix stack info leak in PPP pptp code, from Mathias Krause.

12) Cure locking bug in IPX stack, from Jiri Bohac.

13) Revert SKB fclone memory freeing optimization that is racey and can
    allow accesses to freed up memory, from Eric Dumazet.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (71 commits)
  tcp: Restore RFC5961-compliant behavior for SYN packets
  net: Revert "net: avoid one atomic operation in skb_clone()"
  virtio-net: validate features during probe
  cxgb4 : Fix DCB priority groups being returned in wrong order
  ipx: fix locking regression in ipx_sendmsg and ipx_recvmsg
  openvswitch: Don't validate IPv6 label masks.
  pptp: fix stack info leak in pptp_getname()
  brcmfmac: don't include linux/unaligned/access_ok.h
  cxgb4i : Don't block unload/cxgb4 unload when remote closes TCP connection
  ipv6: delete protocol and unregister rtnetlink when cleanup
  net/mlx4_en: Add VXLAN ndo calls to the PF net device ops too
  bonding: fix curr_active_slave/carrier with loadbalance arp monitoring
  mac80211: minstrel_ht: fix a crash in rate sorting
  vxlan: Inline vxlan_gso_check().
  can: m_can: update to support CAN FD features
  can: m_can: fix incorrect error messages
  can: m_can: add missing delay after setting CCCR_INIT bit
  can: m_can: fix not set can_dlc for remote frame
  can: m_can: fix possible sleep in napi poll
  can: m_can: add missing message RAM initialization
  ...