arm64: cpufeature: Add ID_AA64MMFR4_EL1 handling

Add ID_AA64MMFR4_EL1 to the list of idregs the kernel knows about,
and describe the E2H0 field.

Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20240122181344.258974-6-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>

arm64/cpufeature: Hook new identification registers up to cpufeature

The 2023 architecture extensions have defined several new ID registers,
hook them up to the cpufeature code so we can add feature checks and hwcaps
based on their contents.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20240306-arm64-2023-dpisa-v5-1-c568edc8ed7f@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

arm64: setup: Switch over to GENERIC_CPU_DEVICES using arch_register_cpu()

To allow ACPI's _STA value to hide CPUs that are present, but not
available to online right now due to VMM or firmware policy, the
register_cpu() call needs to be made by the ACPI machinery when ACPI
is in use. This allows it to hide CPUs that are unavailable from sysfs.

Switching to GENERIC_CPU_DEVICES is an intermediate step to allow all
five ACPI architectures to be modified at once.

Switch over to GENERIC_CPU_DEVICES, and provide an arch_register_cpu()
that populates the hotpluggable flag. arch_register_cpu() is also the
interface the ACPI machinery expects.

The struct cpu in struct cpuinfo_arm64 is never used directly, remove
it to use the one GENERIC_CPU_DEVICES provides.

This changes the CPUs visible in sysfs from possible to present, but
on arm64 smp_prepare_cpus() ensures these are the same.

This patch also has the effect of moving the registration of CPUs from
subsys to driver core initialisation, prior to any initcalls running.

Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: "Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>
Reviewed-by: Shaoqin Huang <shahuang@redhat.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Signed-off-by: "Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/E1r5R3b-00Csza-Ku@rmk-PC.armlinux.org.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

arm64/sve: Remove SMCR pseudo register from cpufeature code

For reasons that are not currently apparent during cpufeature enumeration
we maintain a pseudo register for SMCR which records the maximum supported
vector length using the value that would be written to SMCR_EL1.LEN to
configure it. This is not exposed to userspace and is not sufficient for
detecting unsupportable configurations, we need the more detailed checks in
vec_update_vq_map() for that since we can't cope with missing vector
lengths on late CPUs and KVM requires an exactly matching set of supported
vector lengths as EL1 can enumerate VLs directly with the hardware.

Remove the code, replacing the usage in sme_setup() with a query of the
vq_map.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20230913-arm64-vec-len-cpufeature-v1-2-cc69b0600a8a@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

arm64/sve: Remove ZCR pseudo register from cpufeature code

For reasons that are not currently apparent during cpufeature enumeration
we maintain a pseudo register for ZCR which records the maximum supported
vector length using the value that would be written to ZCR_EL1.LEN to
configure it. This is not exposed to userspace and is not sufficient for
detecting unsupportable configurations, we need the more detailed checks in
vec_update_vq_map() for that since we can't cope with missing vector
lengths on late CPUs and KVM requires an exactly matching set of supported
vector lengths as EL1 can enumerate VLs directly with the hardware.

Remove the code, replacing the usage in sve_setup() with a query of the
vq_map.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20230913-arm64-vec-len-cpufeature-v1-1-cc69b0600a8a@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

arm64: cpufeature: add system register ID_AA64MMFR3

Add new system register ID_AA64MMFR3 to the cpufeature infrastructure.

Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Cc: Will Deacon <will@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20230606145859.697944-6-joey.gouly@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

arm64/sme: Expose SMIDR through sysfs

We currently expose MIDR and REVID to userspace through sysfs to enable it
to make decisions based on the specific implementation. Since SME supports
implementations where streaming mode is provided by a separate hardware
unit called a SMCU it provides a similar ID register SMIDR. Expose it to
userspace via sysfs when the system supports SME along with the other ID
registers.

Since we disable the SME priority mapping feature if it is supported by
hardware we currently mask out the SMPS bit which reports that it is
supported.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20220607132857.1358361-1-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>

arm64/sme: Identify supported SME vector lengths at boot

The vector lengths used for SME are controlled through a similar set of
registers to those for SVE and enumerated using a similar algorithm with
some slight differences due to the fact that unlike SVE there are no
restrictions on which combinations of vector lengths can be supported
nor any mandatory vector lengths which must be implemented. Add a new
vector type and implement support for enumerating it.

One slightly awkward feature is that we need to read the current vector
length using a different instruction (or enter streaming mode which
would have the same issue and be higher cost). Rather than add an ops
structure we add special cases directly in the otherwise generic
vec_probe_vqs() function, this is a bit inelegant but it's the only
place where this is an issue.

Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20220419112247.711548-10-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

arm64/sme: Basic enumeration support

This patch introduces basic cpufeature support for discovering the presence
of the Scalable Matrix Extension.

Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20220419112247.711548-9-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

arm64: add ID_AA64ISAR2_EL1 sys register

This is a new ID register, introduced in 8.7.

Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Cc: James Morse <james.morse@arm.com>
Cc: Alexandru Elisei <alexandru.elisei@arm.com>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Reiji Watanabe <reijiw@google.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211210165432.8106-3-joey.gouly@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

arm64: cpuinfo: Split AArch32 registers out into a separate struct

In preparation for late initialisation of the "sanitised" AArch32 register
state, move the AArch32 registers out of 'struct cpuinfo' and into their
own struct definition.

Acked-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20210608180313.11502-2-will@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>

arm64: Check if GMID_EL1.BS is the same on all CPUs

The GMID_EL1.BS field determines the number of tags accessed by the
LDGM/STGM instructions (EL1 and up), used by the kernel for copying or
zeroing page tags.

Taint the kernel if GMID_EL1.BS differs between CPUs but only of
CONFIG_ARM64_MTE is enabled.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Suzuki K Poulose <Suzuki.Poulose@arm.com>
Link: https://lore.kernel.org/r/20210526193621.21559-3-catalin.marinas@arm.com
Signed-off-by: Will Deacon <will@kernel.org>

arm64: Change the cpuinfo_arm64 member type for some sysregs to u64

The architecture has been updated and the CTR_EL0, CNTFRQ_EL0,
DCZID_EL0, MIDR_EL1, REVIDR_EL1 registers are all 64-bit, even if most
of them have a RES0 top 32-bit.

Change their type to u64 in struct cpuinfo_arm64.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Suzuki K Poulose <Suzuki.Poulose@arm.com>
Link: https://lore.kernel.org/r/20210526193621.21559-2-catalin.marinas@arm.com
Signed-off-by: Will Deacon <will@kernel.org>

Revert "arm64: initialize per-cpu offsets earlier"

This reverts commit 353e228eb355be5a65a3c0996c774a0f46737fda.

Qian Cai reports that TX2 no longer boots with his .config as it appears
that task_cpu() gets instrumented and used before KASAN has been
initialised.

Although Mark has a proposed fix, let's take the safe option of reverting
this for now and sorting it out properly later.

Link: https://lore.kernel.org/r/711bc57a314d8d646b41307008db2845b7537b3d.camel@redhat.com
Reported-by: Qian Cai <cai@redhat.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>

arm64: initialize per-cpu offsets earlier

The current initialization of the per-cpu offset register is difficult
to follow and this initialization is not always early enough for
upcoming instrumentation with KCSAN, where the instrumentation callbacks
use the per-cpu offset.

To make it possible to support KCSAN, and to simplify reasoning about
early bringup code, let's initialize the per-cpu offset earlier, before
we run any C code that may consume it. To do so, this patch adds a new
init_this_cpu_offset() helper that's called before the usual
primary/secondary start functions. For consistency, this is also used to
re-initialize the per-cpu offset after the runtime per-cpu areas have
been allocated (which can change CPU0's offset).

So that init_this_cpu_offset() isn't subject to any instrumentation that
might consume the per-cpu offset, it is marked with noinstr, preventing
instrumentation.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20201005164303.21389-1-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>

arm64/cpuinfo: Add ID_MMFR4_EL1 into the cpuinfo_arm64 context

ID_MMFR4_EL1 has been missing in the CPU context (i.e cpuinfo_arm64). This
just adds the register along with other required changes.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org

Suggested-by: Will Deacon <will@kernel.org>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/1589881254-10082-18-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Will Deacon <will@kernel.org>

arm64/cpufeature: Introduce ID_MMFR5 CPU register

This adds basic building blocks required for ID_MMFR5 CPU register which
provides information about the implemented memory model and memory
management support in AArch32 state. This is added per ARM DDI 0487F.a
specification.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: kvmarm@lists.cs.columbia.edu
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org

Suggested-by: Will Deacon <will@kernel.org>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/1589881254-10082-7-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Will Deacon <will@kernel.org>

arm64/cpufeature: Introduce ID_DFR1 CPU register

This adds basic building blocks required for ID_DFR1 CPU register which
provides top level information about the debug system in AArch32 state.
We hide the register from KVM guests, as we don't emulate the 'MTPMU'
feature.

This is added per ARM DDI 0487F.a specification.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: kvmarm@lists.cs.columbia.edu
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org

Suggested-by: Will Deacon <will@kernel.org>
Reviewed-by : Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Link: https://lore.kernel.org/r/1589881254-10082-6-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Will Deacon <will@kernel.org>

arm64/cpufeature: Introduce ID_PFR2 CPU register

This adds basic building blocks required for ID_PFR2 CPU register which
provides information about the AArch32 programmers model which must be
interpreted along with ID_PFR0 and ID_PFR1 CPU registers. This is added
per ARM DDI 0487F.a specification.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: kvmarm@lists.cs.columbia.edu
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org

Suggested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/1589881254-10082-5-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Will Deacon <will@kernel.org>

arm64: Introduce ID_ISAR6 CPU register

This adds basic building blocks required for ID_ISAR6 CPU register which
identifies support for various instruction implementation on AArch32 state.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Cc: James Morse <james.morse@arm.com>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: linux-kernel@vger.kernel.org
Cc: kvmarm@lists.cs.columbia.edu
Acked-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
[will: Ensure SPECRES is treated the same as on A64]
Signed-off-by: Will Deacon <will@kernel.org>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 234

Based on 1 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
distributed in the hope that it will be useful but without any
warranty without even the implied warranty of merchantability or
fitness for a particular purpose see the gnu general public license
for more details you should have received a copy of the gnu general
public license along with this program if not see http www gnu org
licenses

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 503 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Enrico Weigelt <info@metux.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190602204653.811534538@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

arm64/sve: Probe SVE capabilities and usable vector lengths

This patch uses the cpufeatures framework to determine common SVE
capabilities and vector lengths, and configures the runtime SVE
support code appropriately.

ZCR_ELx is not really a feature register, but it is convenient to
use it as a template for recording the maximum vector length
supported by a CPU, using the LEN field. This field is similar to
a feature field in that it is a contiguous bitfield for which we
want to determine the minimum system-wide value. This patch adds
ZCR as a pseudo-register in cpuinfo/cpufeatures, with appropriate
custom code to populate it. Finding the minimum supported value of
the LEN field is left to the cpufeatures framework in the usual
way.

The meaning of ID_AA64ZFR0_EL1 is not architecturally defined yet,
so for now we just require it to be zero.

Note that much of this code is dormant and SVE still won't be used
yet, since system_supports_sve() remains hardwired to false.

Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>

arm64: cpuinfo: Expose MIDR_EL1 and REVIDR_EL1 to sysfs

It can be useful for JIT software to be aware of MIDR_EL1 and
REVIDR_EL1 to ascertain the presence of any core errata that could
affect code generation.

This patch exposes these registers through sysfs:

/sys/devices/system/cpu/cpu$ID/regs/identification/midr_el1
/sys/devices/system/cpu/cpu$ID/regs/identification/revidr_el1

where $ID is the cpu number. For big.LITTLE systems, one can have a
mixture of cores (e.g. Cortex A53 and Cortex A57), thus all CPUs need
to be enumerated.

If the kernel does not have valid information to populate these entries
with, an empty string is returned to userspace.

Cc: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Steve Capper <steve.capper@linaro.org>
[suzuki.poulose@arm.com: ABI documentation updates, hotplug notifiers, kobject changes]
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

arm64: add ARMv8.2 id_aa64mmfr2 boiler plate

ARMv8.2 adds a new feature register id_aa64mmfr2. This patch adds the
cpu feature boiler plate used by the actual features in later patches.

Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

arm64: Consolidate CPU Sanity check to CPU Feature infrastructure

This patch consolidates the CPU Sanity check to the new infrastructure.

Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Suzuki K. Poulose <suzuki.poulose@arm.com>
Tested-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

arm64: Keep track of CPU feature registers

This patch adds an infrastructure to keep track of the CPU feature
registers on the system. For each register, the infrastructure keeps
track of the system wide safe value of the feature bits. Also, tracks
the which fields of a register should be matched strictly across all
the CPUs on the system for the SANITY check infrastructure.

The feature bits are classified into following 3 types depending on
the implication of the possible values. This information is used to
decide the safe value for a feature.

LOWER_SAFE - The smaller value is safer
HIGHER_SAFE - The bigger value is safer
EXACT - We can't decide between the two, so a predefined safe_value is used.

This infrastructure will be later used to make better decisions for:

- Kernel features (e.g, KVM, Debug)
- SANITY Check
- CPU capability
- ELF HWCAP
- Exposing CPU Feature register to userspace.

Signed-off-by: Suzuki K. Poulose <suzuki.poulose@arm.com>
Tested-by: Dave Martin <Dave.Martin@arm.com>
[catalin.marinas@arm.com: whitespace fix]
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

arm64: Move mixed endian support detection

Move the mixed endian support detection code to cpufeature.c
from cpuinfo.c. This also moves the update_cpu_features()
used by mixed endian detection code, which will get more
functionality.

Also moves the ID register field shifts to asm/sysreg.h,
where all the useful definitions will end up in later patches.

Signed-off-by: Suzuki K. Poulose <suzuki.poulose@arm.com>
Tested-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

arm64: sanity checks: add missing AArch32 registers

We don't currently check a number of registers exposed to AArch32 guests
(MVFR{0,1,2}_EL1 and ID_DFR0_EL1), despite the fact these describe
AArch32 feature support exposed to userspace and KVM guests similarly to
AArch64 registers which we do check. We do not expect these registers to
vary across a set of CPUs.

This patch adds said registers to the cpuinfo framework and sanity
checks. No sanity check failures have been observed on a current ARMv8
big.LITTLE platform (Juno).

Cc: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Suzuki K. Poulose <suzuki.poulose@arm.com>
Signed-off-by: Suzuki K. Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

arm64: sanity checks: add ID_AA64DFR{0,1}_EL1

While we currently expect self-hosted debug support to be identical
across CPUs, we don't currently sanity check this.

This patch adds logging of the ID_AA64DFR{0,1}_EL1 values and associated
sanity checking code.

It's not clear to me whether we need to check PMUVer, TraceVer, and
DebugVer, as we don't currently rely on these fields at all.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

arm64: cpuinfo: record cpu system register values

Several kernel subsystems need to know details about CPU system register
values, sometimes for CPUs other than that they are executing on. Rather
than hard-coding system register accesses and cross-calls for these
cases, this patch adds logic to record various system register values at
boot-time. This may be used for feature reporting, firmware bug
detection, etc.

Separate hooks are added for the boot and hotplug paths to enable
one-time intialisation and cold/warm boot value mismatch detection in
later patches.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>