ARM: zynq: Support smp in thumb mode

Add .arm directive to headsmp.S to ensure that the
CPU starts in 32-bit ARM mode and the correct code
size is copied on smp bring-up.
This is related to the fix applied to SoCFPGA by
commit 5616f36713ea
("ARM: SoCFPGA: Fix secondary CPU startup in thumb2 kernel")

Additionally, start secondary CPUs on secondary_startup_arm
to automatically switch from ARM to thumb on a thumb kernel

Signed-off-by: Luis Araneda <luaraneda@gmail.com>
Suggested-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500

Based on 2 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation #

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 4122 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

ARM: zynq: reserve space for jump target in secondary trampoline

Add a zero argument to the .word directive in
zynq_secondary_trampoline. Without an expression the assembler emits
nothing for the .word directive.

This makes it so that the intended range is communicated to ioremap
and outer_flush_range in zynq_cpun_start; e.g. for LE
trampoline_code_size evaluates to 12 now instead of 8.

Found by inspection. I'm not aware of any real problem this fixes.
Tested by doing on online/offline loop on ZC702.

Signed-off-by: Nathan Lynch <nathan_lynch@mentor.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>

ARM: v7 setup function should invalidate L1 cache

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: Florian Fainelli <f.fainelli@gmail.com>
Tested-by: Florian Fainelli <f.fainelli@gmail.com>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Tested-by: Dinh Nguyen <dinguyen@opensource.altera.com>
Acked-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Tested-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Acked-by: Shawn Guo <shawn.guo@linaro.org>
Tested-by: Thierry Reding <treding@nvidia.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Tested-by: Michal Simek <michal.simek@xilinx.com>
Tested-by: Wei Xu <xuwei5@hisilicon.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

ARM: zynq: Enable big-endian

Enable ARCH_SUPPORTS_BIG_ENDIAN in Kconfig.

zynq_secondary_trampoline is the first function
that is called on secondary CPU.
Reference:
"ARM: mcpm: fix big endian issue in mcpm startup code"
(sha1: 519ceb9fd10cd7e836d0aa97b2068cc9e97f463b)

Fix early printk support. Based on:
"ARM: pl01x debug code endian fix"
(sha1: 76e3faf156fa95b6465e747d702b94faf67117fc)

Signed-off-by: Michal Simek <michal.simek@xilinx.com>

arm: zynq: Invalidate L1 in secondary boot

During boot, Linux initiates a clean-invalidate operation only, resulting
in faulty data to be written to the memory system during resume.
Therefore invalidate the L1 in the secondary boot path to avoid these
issues.

Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>

arm: delete __cpuinit/__CPUINIT usage from all ARM users

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 5e427ec2d0 ("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: Paul Gortmaker <paul.gortmaker@windriver.com>

arm: zynq: Add smp support

Zynq is dual core Cortex A9 which starts always
at zero. Using simple trampoline ensure long jump
to secondary_startup code.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>