commit bae0ca2b upstream.

During __v{6,7}_setup, we invalidate the TLBs since we are about to
enable the MMU on return to head.S. Unfortunately, without a subsequent
dsb instruction, the invalidation is not guaranteed to have completed by
the time we write to the sctlr, potentially exposing us to junk/stale
translations cached in the TLB.

This patch reworks the init functions so that the dsb used to ensure
completion of cache/predictor maintenance is also used to ensure
completion of the TLB invalidation.
Reported-by: Albin Tonnerre <Albin.Tonnerre@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>

On Cortex-A15 CPUs up to and including r0p4, in certain rare sequences
of code, the loop buffer may deliver incorrect instructions. This
workaround disables the loop buffer to avoid the erratum.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

System-wide barriers aren't required for situations where we only need
to make visibility and ordering guarantees in the inner-shareable domain
(i.e. we are not dealing with devices or potentially incoherent CPUs).

This patch changes the v7 TLB operations, coherent_user_range and
dcache_clean_area functions to user inner-shareable barriers. For cache
maintenance, only the store access type is required to ensure completion.
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

Commit ae8a8b95 ("ARM: 7691/1: mm: kill unused TLB_CAN_READ_FROM_L1_CACHE
and use ALT_SMP instead") added early function returns for page table
cache flushing operations on ARMv7 SMP CPUs.

Unfortunately, when targetting Thumb-2, these `mov pc, lr' sequences
assemble to 2 bytes which can lead to corruption of the instruction
stream after code patching.

This patch fixes the alternates to use wide (32-bit) instructions for
Thumb-2, therefore ensuring that the patching code works correctly.

Cc: <stable@vger.kernel.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

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: Paul Gortmaker <paul.gortmaker@windriver.com>

This commit fixes the regression on Armada 370 (the kernal hang during
boot) introduced by the commit: "ARM: 7691/1: mm: kill unused
TLB_CAN_READ_FROM_L1_CACHE and use ALT_SMP instead".

When coming out of either a Wait for Interrupt (WFI) or a Wait for
Event (WFE) IDLE states, a specific timing sensitivity exists between
the retiring WFI/WFE instructions and the newly issued subsequent
instructions. This sensitivity can result in a CPU hang scenario.  The
workaround is to insert either a Data Synchronization Barrier (DSB) or
Data Memory Barrier (DMB) command immediately after the WFI/WFE
instruction.

This commit was based on the work of Lior Amsalem, but heavily
modified to apply the errata fix dynamically according to the
processor type thanks to the suggestions of Russell King and Nicolas
Pitre.
Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Tested-by: Willy Tarreau <w@1wt.eu>
Cc: <stable@vger.kernel.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

This commit fixes the ID and mask for the PJ4B which was too
restrictive and didn't match the CPU of the Armada 370 SoC.
Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

This patch adds processor info for ARM Ltd. Cortex-R7.

The R7 has many similarities to the A9 and though the ACTLR layout is not
identical, the bits associated with cache operations broadcasting and SMP
modes are the same for A9, A5 and R7 (Though in the A-class processors the
same bits toggle TLB-ops broadcasting as well as cache-ops)
Signed-off-by: Jonathan Austin <jonathan.austin@arm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
CC: Catalin Marinas <catalin.marinas@arm.com>
CC: Stephen Boyd <sboyd@codeaurora.org>

The ARM CPU suspend code can be selected even for a !CONFIG_MMU
configuration. The resulting kernel will not compile and, even if it did,
would access undefined co-processor registers when executing.

This patch fixes the v6 and v7 CPU suspend code for the nommu case.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Tested-by: Jonathan Austin <jonathan.austin@arm.com>
CC: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> (commit_signer:1/3=33%)
CC: Santosh Shilimkar <santosh.shilimkar@ti.com> (commit_signer:1/3=33%)
CC: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

pj4b cpus are LPAE capable so enable them on LPAE compilations
Signed-off-by: Lior Amsalem <alior@marvell.com>
Tested-by: Franklin <flin@marvell.com>
Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Many ARMv7 cores have hardware page table walkers that can read the L1
cache. This is discoverable from the ID_MMFR3 register, although this
can be expensive to access from the low-level set_pte functions and is a
pain to cache, particularly with multi-cluster systems.

A useful observation is that the multi-processing extensions for ARMv7
require coherent table walks, meaning that we can make use of ALT_SMP
patching in proc-v7-* to patch away the cache flush safely for these
cores.
Reported-by: Albin Tonnerre <Albin.Tonnerre@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Some early versions of the Krait CPU design incorrectly indicate
that they only support the UDIV and SDIV instructions in Thumb
mode when they actually support them in ARM and Thumb mode. It
seems that these CPUs follow the DDI0406B ARM ARM which has two
possible values for the divide instructions field, instead of the
DDI0406C document which has three possible values.

Work around this problem by checking the MIDR against Krait CPUs
with this faulty ISAR0 register and force the hwcaps to indicate
support in both modes.

[sboyd: Rewrote commit text to reflect real reasoning now that
	we autodetect udiv/sdiv]
Signed-off-by: Stepan Moskovchenko <stepanm@codeaurora.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

The ISAR0 register indicates support for the SDIV and UDIV
instructions in both the Thumb and ARM instruction set. Read the
register to detect the supported instructions and update the
elf_hwcap mask as appropriate. This is better than adding more
and more cpuid checks in proc-v7.S for each new cpu variant that
supports these instructions.
Acked-by: Will Deacon <will.deacon@arm.com>
Cc: Stepan Moskovchenko <stepanm@codeaurora.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

If CONFIG_ARCH_MULTIPLATFORM & CONFIG_ARCH_MVEBU are both enabled,
__v7_pj4b_setup is added between __v7_ca9mp_setup and __v7_setup.

But there's no jump instruction added. If the chip is Cortex A5/A9,
it goes through __v7_pj4b_setup also. It results in system hang.
Signed-off-by: Haojian Zhuang <haojian.zhuang@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

In order to support secure and non-secure platforms in multi-platform
kernels, errata work-arounds that access secure only registers need to
be disabled. Make all the errata options that fit in this category
depend on !CONFIG_ARCH_MULTIPLATFORM.

This will effectively remove the errata options as platforms are
converted over to multi-platform.
Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

PJ4B is an implementation of the ARMv7 (such as the Cortex A9 for
example) released by Marvell. This CPU is currently found in
Armada 370 and Armada XP SoCs. This patch provides a support for the
specific initialization of this CPU.
Signed-off-by: Yehuda Yitschak <yehuday@marvell.com>
Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>

Because mov pc,<Rn> never switches instruction set when executed in
Thumb code, Thumb-2 kernels will silently execute the target code
after cpu_reset as Thumb code, even if the passed code pointer
denotes ARM (bit 0 clear).

This patch uses bx instead, ensuring the correct instruction set
for the target code.

Thumb code in the kernel is not supported prior to ARMv7, so other
CPUs are not affected.
Signed-off-by: Dave Martin <dave.martin@linaro.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

The ARMv7 processor setup function __v7_setup() cleans and invalidates the
CPU cache before enabling MMU to start the CPU with a clean CPU local cache.

But on ARMv7 architectures like Cortex-[A15/A8], this code will end
up flushing the L2 caches(up to level of Coherency) which is undesirable
and expensive. The setup functions are used in the CPU hotplug scenario too
and hence flushing all cache levels should be avoided.

This patch replaces the cache flushing call with the newly introduced
v7 dcache LoUIS API where only cache levels up to LoUIS are cleaned and
invalidated when a processors executes __v7_setup which is the expected
behavior.

For processors like A9 and A5 where the L2 cache is an outer one the
behavior should be unchanged.
Reviewed-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Tested-by: Shawn Guo <shawn.guo@linaro.org>

Currently when ThumbEE is not enabled (!CONFIG_ARM_THUMBEE) the ThumbEE
register states are not saved/restored at context switch. The default state
of the ThumbEE Ctrl register (TEECR) allows userspace accesses to the
ThumbEE Base Handler register (TEEHBR). This can cause unexpected behaviour
when people use ThumbEE on !CONFIG_ARM_THUMBEE kernels, as well as allowing
covert communication - eg between userspace tasks running inside chroot
jails.

This patch sets up TEECR in order to prevent user-space access to TEEHBR
when !CONFIG_ARM_THUMBEE. In this case, tasks are sent SIGILL if they try to
access TEEHBR.

Cc: stable@vger.kernel.org
Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Jonathan Austin <jonathan.austin@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Erratum #743622 affects all r2 variants of the Cortex-A9 processor, so
ensure that the workaround is applied regardless of the revision.

Cc: <stable@vger.kernel.org>
Reported-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

On v7, we use the same cache maintenance instructions for data lines
as for unified lines. This was not the case for v6, where HARVARD_CACHE
was defined to indicate the L1 cache topology.

This patch removes the erroneous compile-time check for HARVARD_CACHE in
proc-v7.S, ensuring that we perform I-side invalidation at boot.
Reported-and-Acked-by: Shawn Guo <shawn.guo@linaro.org>

Cc: stable <stable@vger.kernel.org>
Acked-by: Catalin Marinas <Catalin.Marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

The merging of commits 1b6ba46b ("ARM: LPAE: MMU setup for the 3-level
page table format") and b4244738 ("ARM: 7202/1: Add Cortex-A7 proc info")
during the merge window ended up putting the Cortex-A7 proc_info into a
code block guarded by !CONFIG_ARM_LPAE. This makes Cortex-A7 platforms
unbootable when LPAE is enabled.

This patch moves the proc_info structure for Cortex-A7 outside of the
guarded block.

Cc: Pawel Moll <pawel.moll@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Activation conditions for a workaround should not be encoded in the
workaround's direct dependencies if this makes otherwise reasonable
configuration choices impossible.

This patches uses the SMP/UP patching facilities instead to compile
out the workaround if the configuration means that it is definitely
not needed.

This means that configs for buggy silicon can simply select
ARM_ERRATA_751472, without preventing a UP kernel from being built
or duplicatiing knowledge about when to activate the workaround.
This seems the correct way to do things, because the erratum is a
property of the silicon, irrespective of what the kernel config
happens to be.
Signed-off-by: Dave Martin <dave.martin@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

This patch adds processor info for ARM Ltd. Cortex-A7.

A7 is architecturally identical to A15 so it shares the
same SMP initialization code and hwcaps.
Tested-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Pawel Moll <pawel.moll@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

This patch adds the MMU initialisation for the LPAE page table format.
The swapper_pg_dir size with LPAE is 5 rather than 4 pages. A new
proc-v7-3level.S file contains the TTB initialisation, context switch
and PTE setting code with the LPAE. The TTBRx split is based on the
PAGE_OFFSET with TTBR1 used for the kernel mappings. The 36-bit mappings
(supersections) and a few other memory types in mmu.c are conditionally
compiled.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

This patch modifies the proc-v7.S file so that it only contains code
shared between classic MMU and LPAE. The non-common code is factored out
into a separate file.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

The CPU reset functions disable the MMU and therefore must be executed
with an identity mapping in place.

This patch places the CPU reset functions into the .idmap.text section,
causing the idmap code to include them as part of the identity mapping.
Acked-by: Dave Martin <dave.martin@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>

Support for the cpu_suspend functions is only built-in
when CONFIG_PM_SLEEP is enabled, but omap3/4, exynos4
and pxa always call cpu_suspend when CONFIG_PM is enabled.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

There is no need to save and restore the context ID register on ARMv6
and ARMv7 with a temporary page table as we write the context ID
register when we switch back to the real page tables for the thread.

Moreover, the temporary page tables do not contain any non-global
mappings, so the context ID value should not be used.  To be safe,
initialize the register to a reserved context ID value.
Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Tested-by: Shawn Guo <shawn.guo@linaro.org>
Tested-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Only use the preallocated page table during the resume, not while
suspending.  This avoids the overhead of having to switch unnecessarily
to the resume page table in the suspend path.
Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Tested-by: Shawn Guo <shawn.guo@linaro.org>
Tested-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Preallocate a page table and setup an identity mapping for the MMU
enable code.  This means we don't have to "borrow" a page table to
do this, avoiding complexities with L2 cache coherency.
Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Tested-by: Shawn Guo <shawn.guo@linaro.org>
Tested-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

For ARMv7 kernels running in the non-secure world, writing to the
auxillary control register causes an abort, so we must avoid directly
writing the auxillary control register.  If the ACR has already been
reinitialized by SoC code, don't try to restore it.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Add a dsb after the isb to ensure that the previous writes to the
CP15 registers take effect before we enable the MMU.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

cpu_v7_reset disables the MMU and then branches to the provided address.
On Thumb-2 kernels, we should take care to clear the Thumb Exception
enable bit in the System Control Register, otherwise this may wreak
havok in the code to which we are branching (for example, an ARM kernel
image via kexec).
Reviewed-by: Dave Martin <dave.martin@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Commit 66a625a8 (ARM: mm: proc-macros: Add generic proc/cache/tlb struct
definition macros) introduced build errors when PM_SLEEP is not enabled.
The per-CPU do_suspend/do_resume functions are defined via the
preprocessor to constant 0.  However, the macros which use these were
converted to assembly, resulting in undefined references to these
functions.  Fix that by moving the ! ifdef section into proc-macros.S
and deleting it from all effected proc-*.S files.
Acked-by: Dave Martin <dave.martin@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

This patch adds simple definitions of cpu_reset for ARMv6 and ARMv7
cores, which disable the MMU via the SCTLR.
Signed-off-by: Will Deacon <will.deacon@arm.com>

Multicore implementations of the Cortex-A15 require bit 6 of the
auxiliary control register to be set in order for cache and TLB
maintenance operations to be broadcast between CPUs.

This patch adds a new proc_info structure for Cortex-A15, which enables
the SMP bit during setup and includes the new HWCAP for integer
division.
Signed-off-by: Will Deacon <will.deacon@arm.com>

This patch adds processor info for ARM Ltd. Cortex A5,
which has SCU initialisation procedure identical to A9.
Signed-off-by: Pawel Moll <pawel.moll@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

As most of the proc info content is common across all v7
processors, this patch converts existing A9 and generic v7
descriptions into a macro (allowing extra flags in future).
Signed-off-by: Pawel Moll <pawel.moll@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

Signed-off-by: Dave Martin <dave.martin@linaro.org>