We have lots of infrastructure in place to partition multi-core systems
such that we have a group of CPUs that are dedicated to specific task:
cgroups, scheduler and interrupt affinity, and cpuisol= boot parameter.
Still, kernel code will at times interrupt all CPUs in the system via IPIs
for various needs.  These IPIs are useful and cannot be avoided
altogether, but in certain cases it is possible to interrupt only specific
CPUs that have useful work to do and not the entire system.

This patch set, inspired by discussions with Peter Zijlstra and Frederic
Weisbecker when testing the nohz task patch set, is a first stab at trying
to explore doing this by locating the places where such global IPI calls
are being made and turning the global IPI into an IPI for a specific group
of CPUs.  The purpose of the patch set is to get feedback if this is the
right way to go for dealing with this issue and indeed, if the issue is
even worth dealing with at all.  Based on the feedback from this patch set
I plan to offer further patches that address similar issue in other code
paths.

This patch creates an on_each_cpu_mask() and on_each_cpu_cond()
infrastructure API (the former derived from existing arch specific
versions in Tile and Arm) and uses them to turn several global IPI
invocation to per CPU group invocations.

Core kernel:

on_each_cpu_mask() calls a function on processors specified by cpumask,
which may or may not include the local processor.

You must not call this function with disabled interrupts or from a
hardware interrupt handler or from a bottom half handler.

arch/arm:

Note that the generic version is a little different then the Arm one:

1. It has the mask as first parameter
2. It calls the function on the calling CPU with interrupts disabled,
   but this should be OK since the function is called on the other CPUs
   with interrupts disabled anyway.

arch/tile:

The API is the same as the tile private one, but the generic version
also calls the function on the with interrupts disabled in UP case

This is OK since the function is called on the other CPUs
with interrupts disabled.
Signed-off-by: NGilad Ben-Yossef <gilad@benyossef.com>
Reviewed-by: NChristoph Lameter <cl@linux.com>
Acked-by: NChris Metcalf <cmetcalf@tilera.com>
Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Matt Mackall <mpm@selenic.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Sasha Levin <levinsasha928@gmail.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Avi Kivity <avi@redhat.com>
Acked-by: NMichal Nazarewicz <mina86@mina86.org>
Cc: Kosaki Motohiro <kosaki.motohiro@gmail.com>
Cc: Milton Miller <miltonm@bga.com>
Cc: Russell King <linux@arm.linux.org.uk>
Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Disintegrate asm/system.h for ARM.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
cc: Russell King <linux@arm.linux.org.uk>
cc: linux-arm-kernel@lists.infradead.org

Avoid namespace conflicts with drivers over the CP15 definitions by
moving CP15 related prototypes and definitions to a private header
file.
Acked-by: NStephen Warren <swarren@nvidia.com>
Tested-by: Stephen Warren <swarren@nvidia.com> [Tegra]
Acked-by: NH Hartley Sweeten <hsweeten@visionengravers.com>
Tested-by: H Hartley Sweeten <hsweeten@visionengravers.com> [EP93xx]
Acked-by: NNicolas Pitre <nico@linaro.org>
Acked-by: NKukjin Kim <kgene.kim@samsung.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Convert the ep93xx watchdog driver into a platform device and
remove it's dependency on <mach/hardware.h>.
Signed-off-by: NH Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: NRyan Mallon <rmallon@gmail.com>
Signed-off-by: NWim Van Sebroeck <wim@iguana.be>
Reviewed-by: NMika Westerberg <mika.westerberg@iki.fi>
Acked-by: NArnd Bergmann <arnd@arndb.de>

Most parts of the enable / disable API are no longer used and
can be removed.
Signed-off-by: NAdrian Hunter <adrian.hunter@intel.com>
Tested-by: NVenkatraman S <svenkatr@ti.com>
Tested-by: NJaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: NChris Ball <cjb@laptop.org>

set_sleep seems to be unused in omap_hsmmc driver. so get rid of it.
Signed-off-by: NBalaji T K <balajitk@ti.com>
Signed-off-by: NRajendra Nayak <rnayak@ti.com>
Tested-by: NVenkatraman S <svenkatr@ti.com>
Signed-off-by: NChris Ball <cjb@laptop.org>

External circuitry like level shifters may limit the maximum operation
speed of the hsmmc controller. Add a field to struct omap2_hsmmc_info
so boards can adjust the setting on demand.
Signed-off-by: NDaniel Mack <zonque@gmail.com>
Acked-by: NTony Lindgren <tony@atomide.com>
Signed-off-by: NChris Ball <cjb@laptop.org>

Last night's randconfig and the allnoconfig builds spat out the
following warning while building:

warning: (ARM) selects HAVE_BPF_JIT which has unmet direct dependencies (NET)
Acked-by: NMircea Gherzan <mgherzan@gmail.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

It is mainly a simple merge changing the prefix of some
functions to fit the imx-dma namings.

As there are no users of the old dma-v1.c api we can safely
remove this file.
Signed-off-by: NJavier Martin <javier.martin@vista-silicon.com>
Acked-by: NSascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: NVinod Koul <vinod.koul@linux.intel.com>

Now that Neponset, UCB1x00 and SA1111 are all converted to use the IRQ
allocation interfaces, we can enable sparse IRQ support for SA11x0
platforms.

In preparation to convert SA1100 to sparse irq, set .nr_irqs for each machine
and explicitly include mach/irqs.h as needed.
Signed-off-by: NRob Herring <rob.herring@calxeda.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Remove the new unused DMA controller definitions from mach/SA-1100.h.
These are now private to the SA-11x0 DMA engine driver and contained
within the driver.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Now that all users are converted over to using the DMA engine API,
we can get rid of the old platform dependent DMA driver.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

The sa1111 support will ioremap() the device; there is no need for
platforms to setup a static mapping for this.  Remove the static
mapping for this device from badge4, jornada720 and neponset.
Acked-by: NNicolas Pitre <nico@linaro.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Use dev_err() to report device specific errors rather than printk().
Acked-by: NNicolas Pitre <nico@linaro.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Move the releasing of resources out of the release function - this
allows a cleaner and more conventional arrangement of the registration
failure paths and a saner unregistration process for these devices.
Acked-by: NNicolas Pitre <nico@linaro.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

It's pointless registering the PS/2 interfaces with the dmabounce code
when there's no DMA support for these in hardware, so only setup the
DMA masks for two subdevices which support DMA - the OHCI and SAC.
Acked-by: NNicolas Pitre <nico@linaro.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Use the bus notifier to register sa1111 devices with dmabounce, rather
than after the device has been registered, potentially racing with
driver binding.
Acked-by: NNicolas Pitre <nico@linaro.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Move the USB interface register definitions into the driver, rather
than keeping them in a common place.
Acked-by: NNicolas Pitre <nico@linaro.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Move the PCMCIA interface register definitions into the driver, rather
than keeping them in a common place.
Acked-by: NNicolas Pitre <nico@linaro.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Move the PS/2 interface register definitions into the driver, rather
than keeping them in a common location.
Acked-by: NNicolas Pitre <nico@linaro.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Get rid of the unused GPIO register definitions - we access GPIO
registers through the base + offset method, and having the phys
address definitions is unnecessary duplication.
Acked-by: NNicolas Pitre <nico@linaro.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Some platforms don't want certain devices to be registered, because,
eg, the interface is not wired.  Provide a way for platforms to
prevent various devices from being registered via a devid bitmask in
the platform data.
Acked-by: NNicolas Pitre <nico@linaro.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

XIP_VIRT_ADDR is needed for XIP builds and currently only defined for
builds with CONFIG_MMU.

Also provide it for no-MMU builds to make it possible to build an XIP
kernel for MMU-less machines. As these lack an MMU it has to be an
identity mapping.
Acked-by: NNicolas Pitre <nico@linaro.org>
Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This converts the Integrator AP/CP to use sparse IRQs.
Tested on both machines.
Acked-by: NRob Herring <rob.herring@calxeda.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Based of Matt Evans's PPC64 implementation.

The compiler generates ARM instructions but interworking is
supported for Thumb2 kernels.

Supports both little and big endian. Unaligned loads are emitted
for ARMv6+. Not all the BPF opcodes that deal with ancillary data
are supported. The scratch memory of the filter lives on the stack.
Hardware integer division is used if it is available.

Enabled in the same way as for x86-64 and PPC64:

	echo 1 > /proc/sys/net/core/bpf_jit_enable

A value greater than 1 enables opcode output.
Signed-off-by: NMircea Gherzan <mgherzan@gmail.com>
Acked-by: NDavid S. Miller <davem@davemloft.net>
Acked-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Add the arch-specific code to support jump labels for ARM and Thumb-2.

This code will only be activated on compilers that are capable of
building it.  It has been tested with GCC 4.6 patched with the patch
from GCC bug 48637.

Cc: Jason Baron <jbaron@redhat.com>
Signed-off-by: NRabin Vincent <rabin@rab.in>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This is a very simple method for code running in an emulator, or under
the supervision of a debugger, to use I/O facilities on the controlling
host.

Tested with OpenOCD, and ARM's Fast Models.

Details on semihosting can be found in chapter 8 of
DUI0203I_rvct_developer_guide.pdf from ARM Ltd.
Signed-off-by: NNicolas Pitre <nicolas.pitre@linaro.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

As described in e6fa16ab ("signal: sigprocmask() should do
retarget_shared_pending()") the modification of current->blocked is
incorrect as we need to check for shared signals we're about to block.

Also, use the new helper function introduced in commit 5e6292c0
("signal: add block_sigmask() for adding sigmask to current->blocked")
which centralises the code for updating current->blocked after
successfully delivering a signal and reduces the amount of duplicate code
across architectures.  In the past some architectures got this code wrong,
so using this helper function should stop that from happening again.

Cc: Arnd Bergmann <arnd.bergmann@linaro.org>
Cc: Dave Martin <dave.martin@linaro.org>
Cc: Nicolas Pitre <nicolas.pitre@linaro.org>
Cc: Will Deacon <will.deacon@arm.com>
Acked-by: NOleg Nesterov <oleg@redhat.com>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

The address limit is already set in flush_old_exec() so this
set_fs(USER_DS) is redundant.
Signed-off-by: NMathias Krause <minipli@googlemail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Extract out the code patching code from kprobes so that it can be used
from the jump label code.  Additionally, the separated code:

 - Uses the IS_ENABLED() macros instead of the #ifdefs for THUMB2
   support

 - Unifies the two separate functions in kprobes, providing one function
   that uses stop_machine() internally, and one that can be called from
   stop_machine() directly

 - Patches the text on all CPUs only on processors requiring software
   broadcasting of cache operations
Acked-by: NJon Medhurst <tixy@yxit.co.uk>
Tested-by: NJon Medhurst <tixy@yxit.co.uk>
Signed-off-by: NRabin Vincent <rabin@rab.in>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Extract out the instruction generation code so that it can be used
for jump labels too.
Signed-off-by: NRabin Vincent <rabin@rab.in>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

As commit 592201a9 (ARM: Thumb-2: Support Thumb-2 in undefined
instruction handler) says:

    32-bit Thumb instructions are specified in the form:
        ((first_half << 16 ) | second_half)
    which matches the layout used by the ARM ARM.

Convert the ftrace code to use the same format to avoid the usage of
different formats in kernel code.
Acked-by: NDave Martin <dave.martin@linaro.org>
Signed-off-by: NRabin Vincent <rabin@rab.in>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Before replacing an instruction, the ftrace code determines what the old
instruction should be and verifies that that's what's really there in
memory before replacing it.  This is useful if for example a bug in
mcountrecord causes it to record wrong locations.

However, in cases where we replace call sites in entry-common.S, these
checks are not needed.  For these, we currently just memcpy() the memory
content and then "verify" it -- this is quite useless and can be
removed.
Signed-off-by: NRabin Vincent <rabin@rab.in>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

The kexec machine crash code can be called in interrupt context via a
sysrq trigger made using the magic key combination. If the irq chip
dealing with the serial interrupt is using the fasteoi flow handler,
then we will never EOI the interrupt because the interrupt handler will
be fatal. In the case of a GIC, this results in the crash kernel not
receiving interrupts on that CPU interface.

This patch adds code (based on the PowerPC implementation) to EOI any
pending interrupts on the crash CPU before masking and disabling all
interrupts. Secondary cores are not a problem since they are placed into
a cpu_relax() loop via an IPI.
Reported-by: NLei Wen <leiwen@marvell.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

On Versatile Express, the PCI Express buses are broken and unusable, so
we aren't going to support PCI/ISA IO cycles on this platform.  Remove
the PCI/ISA IO inb et.al. support for this platform.
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Avoid potential build problems caused by lacking mach/irqs.h includes
on non-OF builds caused by an errant include in asm/prom.h.  asm/prom.h
requires nothing from asm/irq.h, as Grant says:

On Mon, Feb 06, 2012 at 05:56:23AM +0000, Grant Likely wrote:
> On Sat, Feb 04, 2012 at 10:17:48PM +0000, Russell King wrote:
> > Finally, do we need asm/irq.h in our asm/prom.h ?  That's causing
> > fragility between DT and non-DT builds, because people are finding
> > that their DT builds work without their mach/irqs.h includes but
> > fail when built with non-DT.  The only thing which DT might need -
> > at the most - is NR_IRQS, but I'd hope with things like irq domains
> > it doesn't actually require it.
>
> I don't think so.  There may be a file or two that break because they're
> not including everything they need, but I don't think anything in the
> header requires it.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Print debug information on user faults for SIGBUS if user_debug = 16
in the kernel command line.

Reference: <1327333344-26340-1-git-send-email-javi.merino@arm.com>
Signed-off-by: NJavi Merino <javi.merino@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

The irq_start and hwirq_base assignment code is fairly hairy and ended
up being difficult to read following a conflict resolution for 3.2.

This patch rearranges the code slightly to make it easier to read.

Cc: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

ARM unconditionally selects CONFIG_GENERIC_HARDIRQS, so the definition
of for_each_irq_desc will check that the desc is non-NULL anyway.

This patch removes a redundant check from the IRQ migration code.
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>