Currently, there are several issues with how MPU is setup:

 1. We won't boot if MPU is missing
 2. We won't boot if use XIP
 3. Further extension of MPU setup requires asm skills

The 1st point can be relaxed, so we can continue with boot CPU even if
MPU is missed and fail boot for secondaries only. To address the 2nd
point we could create region covering CONFIG_XIP_PHYS_ADDR - _end and
that might work for the first stage of MPU enable, but due to MPU's
alignment requirement we could cover too much, IOW we need more
flexibility in how we're partitioning memory regions... and it'd be
hardly possible to archive because of the 3rd point.

This patch is trying to address 1st and 3rd issues and paves the path
for 2nd and further improvements.

The most visible change introduced with this patch is that we start
using mpu_rgn_info array (as it was supposed?), so change in MPU setup
done by boot CPU is recorded there and feed to secondaries. It
allows us to keep minimal region setup for boot CPU and do the rest in
C. Since we start programming MPU regions in C evaluation of MPU
constrains (number of regions supported and minimal region order) can
be done once, which in turn open possibility to free-up "probe"
region early.
Tested-by: NSzemző András <sza@esh.hu>
Tested-by: NAlexandre TORGUE <alexandre.torgue@st.com>
Tested-by: NBenjamin Gaignard <benjamin.gaignard@linaro.org>
Signed-off-by: NVladimir Murzin <vladimir.murzin@arm.com>
Signed-off-by: NRussell King <rmk+kernel@armlinux.org.uk>

The core framework does not modify smp_operations structures.
To clarify it, this commit adds 'const' qualifier to the 'ops'
member of struct of_cpu_method and the 'smp' member of struct
machine_desc.

This change allows each SoC code to add 'const' qualifier to its
smp_operation structure.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This function just copies '*ops' to 'smp_ops', so the given
structure '*ops' is not modified at all.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: NStephen Boyd <sboyd@codeaurora.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

The only caller of cpu_die() on ARM is arch_cpu_idle_dead(), so
let's simplify the code by renaming cpu_die() to
arch_cpu_idle_dead(). While were here, drop the __ref annotation
because __cpuinit is gone nowadays.
Signed-off-by: NStephen Boyd <sboyd@codeaurora.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Writes to /sys/.../cpuX/online fail if we determine the platform
doesn't support hotplug for that CPU. Furthermore, if the cpu_die
op isn't specified the system hangs when we try to offline a CPU
and it comes right back online unexpectedly. Let's figure this
stuff out before we make the sysfs nodes so that the online file
doesn't even exist if it isn't (at least sometimes) possible to
hotplug the CPU.

Add a new 'cpu_can_disable' op and repoint all 'cpu_disable'
implementations at it because all implementers use the op to
indicate if a CPU can be hotplugged or not in a static fashion.
With PSCI we may need to add a 'cpu_disable' op so that the
secure OS can be migrated off the CPU we're trying to hotplug.
In this case, the 'cpu_can_disable' op will indicate that all
CPUs are hotpluggable by returning true, but the 'cpu_disable' op
will make a PSCI migration call and occasionally fail, denying
the hotplug of a CPU. This shouldn't be any worse than x86 where
we may indicate that all CPUs are hotpluggable but occasionally
we can't offline a CPU due to check_irq_vectors_for_cpu_disable()
failing to find a CPU to move vectors to.

Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Nicolas Pitre <nico@linaro.org>
Cc: Dave Martin <Dave.Martin@arm.com>
Acked-by: Simon Horman <horms@verge.net.au> [shmobile portion]
Tested-by: NSimon Horman <horms@verge.net.au>
Cc: Magnus Damm <magnus.damm@gmail.com>
Cc: <linux-sh@vger.kernel.org>
Tested-by: NTyler Baker <tyler.baker@linaro.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NStephen Boyd <sboyd@codeaurora.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Put secondary_startup_arm() prototype in arch/arm/include/asm/smp.h
so users doesn't have to add extern prototype in their code.
Signed-off-by: NYingjoe Chen <yingjoe.chen@mediatek.com>
Reviewed-by: NMatthias Brugger <matthias.bgg@gmail.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Re-engineer the LPAE TTBR setup code.  Rather than passing some shifted
address in order to fit in a CPU register, pass either a full physical
address (in the case of r4, r5 for TTBR0) or a PFN (for TTBR1).

This removes the ARCH_PGD_SHIFT hack, and the last dangerous user of
cpu_set_ttbr() in the secondary CPU startup code path (which was there
to re-set TTBR1 to the appropriate high physical address space on
Keystone2.)
Tested-by: NMurali Karicheri <m-karicheri2@ti.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

After becoming a mandatory function, boot_secondary() is no longer used
outside arch/arm/kernel/smp.c. Hence remove its public prototype, and,
as suggested by Arnd, let it be absorbed by its single caller.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Building an SMP kernel for the sunxi platform with THUMB2 instructions
fails with this error at the moment:

headsmp.S:7: Error: Thumb encoding does not support an immediate here -- `msr cpsr_fsxc,#0xd3'

Since the generic secondary_startup function already does
the same thing in a safe way, we can just drop the private
sunxi implementation and jump straight to secondary_startup.
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Cc: Maxime Ripard <maxime.ripard@free-electrons.com>

The goal of multi-platform kernels is to remove the need for mach
directories and machine descriptors. To further that goal,
introduce CPU_METHOD_OF_DECLARE() to allow cpu hotplug/smp
support to be separated from the machine descriptors.
Implementers should specify an enable-method property in their
cpus node and then implement a matching set of smp_ops in their
hotplug/smp code, wiring it up with the CPU_METHOD_OF_DECLARE()
macro. When the kernel is compiled we'll collect all the
enable-method smp_ops into one section for use at boot.

At boot time we'll look for an enable-method in each cpu node and
try to match that against all known CPU enable methods in the
kernel. If there are no enable-methods in the cpu nodes we
fallback to the cpus node and try to use any enable-method found
there. If that doesn't work we fall back to the old way of using
the machine descriptor.
Acked-by: NMark Rutland <mark.rutland@arm.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: <devicetree@vger.kernel.org>
Signed-off-by: NStephen Boyd <sboyd@codeaurora.org>
Signed-off-by: NKumar Gala <galak@codeaurora.org>

We need a mechanism to let an inbound CPU signal that it is alive before
even getting into the kernel environment i.e. from early assembly code.
Using an IPI is the simplest way to achieve that.

This adds some basic infrastructure to register a struct completion
pointer to be "completed" when the dedicated IPI for this task is
received.
Signed-off-by: NNicolas Pitre <nico@linaro.org>

The MPU initialisation on the primary core is performed in two stages, one
minimal stage to ensure the CPU can boot and a second one after
sanity_check_meminfo. As the memory configuration is known by the time we
boot secondary cores only a single step is necessary, provided the values
for DRSR are passed to secondaries.

This patch implements this arrangement. The configuration generated for the
MPU regions is made available to the secondary core, which can then use the
asm MPU intialisation code to program a complete region configuration.

This is necessary for SMP configurations without an MMU, as the MPU
initialisation is the only way to ensure that memory is specified as
'shared'.
Signed-off-by: NJonathan Austin <jonathan.austin@arm.com>
Reviewed-by: NWill Deacon <will.deacon@arm.com>
CC: Nicolas Pitre <nico@linaro.org>

Add function arch_send_wakeup_ipi_mask(), so that platform code can
use it as an easy way to wake up cores that are in WFI.
Signed-off-by: NShawn Guo <shawn.guo@linaro.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Almost each SMP platform defines pen_release to manage booting secondary
CPUs. This of course clashes with the single zImage effort.

Add the pen_release definition to the ARM SMP code, and remove all others.
This should only be used by platforms which lack any kind of CPU power
management...
Reported-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>
Acked-by: NNicolas Pitre <nico@linaro.org>
Signed-off-by: NArnd Bergmann <arnd@arndb.de>

Now that all SMP platforms have been converted to use struct
smp_operations, remove the "weak" attribute from the hooks
in smp.c, and make the functions static wherever possible.
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>
Acked-by: NNicolas Pitre <nico@linaro.org>
Signed-off-by: NArnd Bergmann <arnd@arndb.de>

This adds a 'struct smp_operations' to abstract the CPU initialization
and hot plugging functions on SMP systems, which otherwise conflict
in a multiplatform kernel. This also helps shmobile and potentially
others that have more than one method to do these.

To allow the kernel to continue building, the platform hooks are
defined as weak symbols which are overrided by the platform code.
Once all platforms are converted, the "weak" attribute will be
removed and the function made static.

Unlike the original version from Marc, this new version from Arnd
does not use a generalized abstraction for per-soc data structures
but only tries to solve the problem for the SMP operations. This
way, we can collapse the previous four data structures into a
single struct, which is less systematic but also easier to follow
as a causal reader.
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>
Acked-by: NNicolas Pitre <nico@fluxnic.net>
Signed-off-by: NArnd Bergmann <arnd@arndb.de>

It turns out that the logical CPU mapping is useful even when !CONFIG_SMP
for manipulation of devices like interrupt and power controllers when
running a UP kernel on a CPU other than 0. This can happen when kexecing
a UP image from an SMP kernel.

In the future, multi-cluster systems running AMP configurations will
require something similar for mapping cluster IDs, so it makes sense to
decouple this logic in preparation for this support.
Acked-by: NYang Bai <hamo.by@gmail.com>
Acked-by: NMarc Zyngier <marc.zyngier@arm.com>
Reported-by: NJoerg Roedel <joerg.roedel@amd.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

PPI handling is a bit of an odd beast. It uses its own low level
handling code and is hardwired to the local timers (hence lacking
a registration interface).

Instead, switch the low handling to the normal SPI handling code.
PPIs are handled by the handle_percpu_devid_irq flow.

This also allows the removal of some duplicated code.

Cc: Kukjin Kim <kgene.kim@samsung.com>
Cc: David Brown <davidb@codeaurora.org>
Cc: Bryan Huntsman <bryanh@codeaurora.org>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Magnus Damm <magnus.damm@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Acked-by: NDavid Brown <davidb@codeaurora.org>
Tested-by: NDavid Brown <davidb@codeaurora.org>
Tested-by: NShawn Guo <shawn.guo@linaro.org>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

In order to be able to handle IPI directly from C code instead of
assembly code, introduce handle_IPI(), which is modeled after handle_IRQ().
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

To allow booting Linux on a CPU with physical ID != 0, we need to
provide a mapping from the logical CPU number to the physical CPU
number.

This patch adds such a mapping and populates it during boot.
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This patch makes TTBR1 point to swapper_pg_dir so that global, kernel
mappings can be used exclusively on v6 and v7 cores where they are
needed.
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This constant hasn't been used since before the git era (2.6.12) and thus
can be dropped.
Signed-off-by: NStephen Boyd <sboyd@codeaurora.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Richard Weinberger <richard@nod.at>
Cc: Hirokazu Takata <takata@linux-m32r.org>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Rather than having each platform class provide a mach/smp.h header for
smp_cross_call(), arrange for them to register the function with the
core ARM SMP code instead.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

There is a certain amount of smp_prepare_cpus() which doesn't belong
in the platform support code - that is, code which is invariant to the
SMP implementation.  Move this code into arch/arm/kernel/smp.c, and
add a platform_ prefix to the original function.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

As per x86, align the initial column according to how many IRQs we
have.  Also, provide an english explaination for the 'LOC:' and
'IPI:' lines.
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This allows us to use smp_cross_call() to trigger a number of different
software generated interrupts, rather than combining them all on one
SGI.  Recover the SGI number via do_IPI.
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Consistently name all SMP platform related functions.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Now everyone is converted to arch_send_call_function_ipi_mask, remove
the shim and the #defines.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Convert cpu_*_mask bit twiddling to the new set_cpu_*() API.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

The ARM SMP code wasn't properly updated for the cpumask changes, which
results in smp_timer_broadcast() broadcasting ticks to non-online CPUs.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

All the cases where the local timer for a CPU is accessed happen on the
corresponding current CPU, hence no need to access the per-CPU local
timer mappings.
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>

This just leaves include/asm-arm/plat-* to deal with.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Move platform independent header files to arch/arm/include/asm, leaving
those in asm/arch* and asm/plat* alone.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This converts arm to use the new helpers for smp_call_function() and
friends, and adds support for smp_call_function_single().

Fixups and testing done by Catalin Marinas <catalin.marinas@arm.com>

Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

This patch adds dummy local timers for each CPU so that the board clock
device is used to broadcast events to the other CPUs. The patch also
adds the declaration for the dummy_timer_setup function (the equivalent
of local_timer_setup when CONFIG_LOCAL_TIMERS is not set).

Due to the way clockevents work, the dummy timer on the first CPU has to
be registered before the board timer.
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This patch adds the smp_call_function_single and smp_timer_broadcast
functions and modifies ipi_timer to call the platform-specific function
local_timer_interrupt.
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Signed-off-by: NDavid Woodhouse <dwmw2@infradead.org>

A change to the SMP initialisation caused the following oops:

 CPU1: Booted secondary processor
 CPU1: D VIPT write-back cache
 CPU1: I cache: 32768 bytes, associativity 4, 32 byte lines, 256 sets
 CPU1: D cache: 32768 bytes, associativity 4, 32 byte lines, 256 sets
 <7>Calibrating delay loop... 83.14 BogoMIPS (lpj=415744)
 <1>Unable to handle kernel NULL pointer dereference at virtual address 0000001c
 ...
 PC is at enqueue_task+0x1c/0x64
 LR is at activate_task+0xcc/0xe4

SMP initialisation now requires cpu_possible_map to be initialised in
setup_arch().  Move this from smp_prepare_cpus() to smp_init_cpus()
and call it from our setup_arch() if CONFIG_SMP is enabled.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Add infrastructure for supporting per-cpu local timers to update
the profiling information and update system time accounting.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>