All ARMv5 and older CPUs invalidate their caches in the early assembly
setup function, prior to enabling the MMU.  This is because the L1
cache should not contain any data relevant to the execution of the
kernel at this point; all data should have been flushed out to memory.

This requirement should also be true for ARMv6 and ARMv7 CPUs - indeed,
these typically do not search their caches when caching is disabled (as
it needs to be when the MMU is disabled) so this change should be safe.

ARMv7 allows there to be CPUs which search their caches while caching is
disabled, and it's permitted that the cache is uninitialised at boot;
for these, the architecture reference manual requires that an
implementation specific code sequence is used immediately after reset
to ensure that the cache is placed into a sane state.  Such
functionality is definitely outside the remit of the Linux kernel, and
must be done by the SoC's firmware before _any_ CPU gets to the Linux
kernel.

Changing the data cache clean+invalidate to a mere invalidate allows us
to get rid of a lot of platform specific hacks around this issue for
their secondary CPU bringup paths - some of which were buggy.
Reviewed-by: NFlorian Fainelli <f.fainelli@gmail.com>
Tested-by: NFlorian Fainelli <f.fainelli@gmail.com>
Tested-by: NHeiko Stuebner <heiko@sntech.de>
Tested-by: NDinh Nguyen <dinguyen@opensource.altera.com>
Acked-by: NSebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Tested-by: NSebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Acked-by: NShawn Guo <shawn.guo@linaro.org>
Tested-by: NThierry Reding <treding@nvidia.com>
Acked-by: NThierry Reding <treding@nvidia.com>
Tested-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Tested-by: NMichal Simek <michal.simek@xilinx.com>
Tested-by: NWei Xu <xuwei5@hisilicon.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

ARMv6 and greater introduced a new instruction ("bx") which can be used
to return from function calls.  Recent CPUs perform better when the
"bx lr" instruction is used rather than the "mov pc, lr" instruction,
and this sequence is strongly recommended to be used by the ARM
architecture manual (section A.4.1.1).

We provide a new macro "ret" with all its variants for the condition
code which will resolve to the appropriate instruction.

Rather than doing this piecemeal, and miss some instances, change all
the "mov pc" instances to use the new macro, with the exception of
the "movs" instruction and the kprobes code.  This allows us to detect
the "mov pc, lr" case and fix it up - and also gives us the possibility
of deploying this for other registers depending on the CPU selection.
Reported-by: NWill Deacon <will.deacon@arm.com>
Tested-by: Stephen Warren <swarren@nvidia.com> # Tegra Jetson TK1
Tested-by: Robert Jarzmik <robert.jarzmik@free.fr> # mioa701_bootresume.S
Tested-by: Andrew Lunn <andrew@lunn.ch> # Kirkwood
Tested-by: NShawn Guo <shawn.guo@freescale.com>
Tested-by: Tony Lindgren <tony@atomide.com> # OMAPs
Tested-by: Gregory CLEMENT <gregory.clement@free-electrons.com> # Armada XP, 375, 385
Acked-by: Sekhar Nori <nsekhar@ti.com> # DaVinci
Acked-by: Christoffer Dall <christoffer.dall@linaro.org> # kvm/hyp
Acked-by: Haojian Zhuang <haojian.zhuang@gmail.com> # PXA3xx
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> # Xen
Tested-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> # ARMv7M
Tested-by: Simon Horman <horms+renesas@verge.net.au> # Shmobile
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Allow build of platsmp.c and headsmp.S even though
SMP is disabled in the kernel configuration. With
this in place it is possible to share the reset
vector setup code with power management code that
needs to be built even though SMP is disabled.
Signed-off-by: NMagnus Damm <damm+renesas@opensource.se>
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>

Introduce shmobile_boot_size that can be used by
future SMP code to determine the size of the boot
code that needs to be copied to internal SRAM.
Signed-off-by: NMagnus Damm <damm@opensource.se>
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>

Add per-CPU SMP boot / sleep code that can be used by all
SoCs included in mach-shmobile.

The boot code reads out the per-CPU MPIDR id value and
matches it with the value stored for any CPU number, and
if there is a match and the boot function is set as well
then the boot function will be executed.

The sleep code simply uses WFI and then jumps back to the
boot code to see if anyone has asked to wake up that CPU,
if not it will sleep again.
Signed-off-by: NMagnus Damm <damm@opensource.se>
[horms+renesas@verge.net.au: Remove trailing whitespace]
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>

In thumb2 mode instructions are not align to 4 byte. This patch insert
align directives before putting 4 byte data.
Signed-off-by: NTetsuyuki Kobayashi <koba@kmckk.co.jp>
Acked-by: NMagnus Damm <damm@opensource.se>
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>

Instructions start from boot vector must be ARM mode.
This patch specify ARM mode explicitly and use 'bx' instruction to be
able to change to Thumb mode.
Signed-off-by: NTetsuyuki Kobayashi <koba@kmckk.co.jp>
Acked-by: NMagnus Damm <damm@opensource.se>
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>

The __cpuinit type of throwaway sections might have made sense
some time ago when RAM was more constrained, but now the savings
do not offset the cost and complications.  For example, the fix in
commit 5e427ec2 ("x86: Fix bit corruption at CPU resume time")
is a good example of the nasty type of bugs that can be created
with improper use of the various __init prefixes.

After a discussion on LKML[1] it was decided that cpuinit should go
the way of devinit and be phased out.  Once all the users are gone,
we can then finally remove the macros themselves from linux/init.h.

Note that some harmless section mismatch warnings may result, since
notify_cpu_starting() and cpu_up() are arch independent (kernel/cpu.c)
and are flagged as __cpuinit  -- so if we remove the __cpuinit from
the arch specific callers, we will also get section mismatch warnings.
As an intermediate step, we intend to turn the linux/init.h cpuinit
related content into no-ops as early as possible, since that will get
rid of these warnings.  In any case, they are temporary and harmless.

This removes all the ARM uses of the __cpuinit macros from C code,
and all __CPUINIT from assembly code.  It also had two ".previous"
section statements that were paired off against __CPUINIT
(aka .section ".cpuinit.text") that also get removed here.

[1] https://lkml.org/lkml/2013/5/20/589

Cc: Russell King <linux@arm.linux.org.uk>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>

Add code for mach-shmobile to allow specifying boot function
and argument. Will initially be used for SMP together with SCU
but may in the future also be used for deep sleep resume. This
patch removes one inline virtual to physical address conversion.
Signed-off-by: NMagnus Damm <damm@opensource.se>
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>

mach-socfpga is another platform that needs to use
v7_invalidate_l1 to bringup additional cores. There was a comment that
the ideal place for v7_invalidate_l1 should be in arm/mm/cache-v7.S
Signed-off-by: NDinh Nguyen <dinguyen@altera.com>
Acked-by: NSimon Horman <horms+renesas@verge.net.au>
Acked-by: NStephen Warren <swarren@nvidia.com>
Reviewed-by: NPavel Machek <pavel@denx.de>
Reviewed-by: NSantosh Shilimkar <santosh.shilimkar@ti.com>
Tested-by: NPavel Machek <pavel@denx.de>
Tested-by: NStephen Warren <swarren@nvidia.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Olof Johansson <olof@lixom.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: Sascha Hauer <kernel@pengutronix.de>
Cc: Magnus Damm <magnus.damm@gmail.com>
Signed-off-by: NOlof Johansson <olof@lixom.net>

Make sure L1 caches are invalidated when booting secondary
cores. Needed to boot all mach-shmobile SMP systems that
are using Cortex-A9 including sh73a0, r8a7779 and EMEV2.

Thanks to imx and tegra guys for actual code.
Signed-off-by: NMagnus Damm <damm@opensource.se>
Tested-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>

Convert the low level SMP assembly code for SH-Mobile ARM
from using the INIT to the CPUINIT section. This unbreaks
onlining of CPUs using the CPU hotplug interface:

echo 1 > /sys/devices/system/cpu/cpu1/online

Without this fix the reset vector code used by CPU hotplug
will be freed as init section data and CPU cores cannot
be brought online.
Signed-off-by: NMagnus Damm <damm@opensource.se>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

Git commit f4117ac9
introduced PLAT_PHYS_OFFSET, but headsmp.S was left
unchanged which results in a compile error:

  AS      arch/arm/mach-shmobile/headsmp.o
arch/arm/mach-shmobile/headsmp.S: Assembler messages:
arch/arm/mach-shmobile/headsmp.S:27: Error: undefined symbol `secondary_startup' in operation
arch/arm/mach-shmobile/headsmp.S:27: Error: undefined symbol `PHYS_OFFSET' in operation
make[1]: *** [arch/arm/mach-shmobile/headsmp.o] Error 1
make[1]: *** Waiting for unfinished jobs....
Signed-off-by: NMagnus Damm <damm@opensource.se>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

Use PAGE_OFFSET and PHYS_OFFSET for secondary_startup
entry point as recommended by Russell King.
Signed-off-by: NMagnus Damm <damm@opensource.se>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

Add SMP base support for R-Mobile / SH-Mobile processors.

This patch contains all base code to support CONFIG_SMP
regardless of ARCH_SHMOBILE processor type. Both local timer
and CPU hotplug are supported, but no processor specific
code is included.

At this point only the default behavior is in place, so
a single core will always be used even though CONFIG_SMP
is enabled on multicore systems.

The SMP Kconfig entry for arch/arm/Kconfig is excluded from
this patch to simplify merging.
Signed-off-by: NMagnus Damm <damm@opensource.se>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>