With introduction of FEAT_STATE_CHECK_ASYMMETRIC, the asymmetry of cores
can be handled. FEAT_TCR2 is one of the features which can be
asymmetric across cores and the respective support is added here.
Adding a function to handle this asymmetry by re-visting the
feature presence on running core.
There are two possible cases:
- If the primary core has the feature and secondary does not have it
then the feature is disabled.
- If the primary does not have the feature and secondary has it then,
the feature need to be enabled in secondary cores.
Signed-off-by: Jayanth Dodderi Chidanand <jayanthdodderi.chidanand@arm.com>
Change-Id: I73a70891d52268ddfa4effe40edf04115f5821ca
Currently, as part of the context_memory report, we explicitly
list the EL3, EL1 and EL2 registers and memory usage per CPU
for each world. The remaining bits in the cpu_context_t structure
are grouped and listed as other section.
This patch enhances this part, by individually listing all the
remaining bits (GPREGS, PAUTH_REGS) separately providing
a much detailed overview of the context memory consumption
amongst the registers.
The patch has been tested on the CI with the following patch
and the results are summarised precisely.
[https://review.trustedfirmware.org/c/ci/tf-a-ci-scripts/+/28849]
Change-Id: I16f210b605ddd7900600519520accf1ccd057bc7
Signed-off-by: Jayanth Dodderi Chidanand <jayanthdodderi.chidanand@arm.com>
* Currently, EL1 context is included in cpu_context_t by default
for all the build configurations.
As part of the cpu context structure, we hold a copy of EL1, EL2
system registers, per world per PE. This context structure is
enormous and will continue to grow bigger with the addition of
new features incorporating new registers.
* Ideally, EL3 should save and restore the system registers at its next
lower exception level, which is EL2 in majority of the configurations.
* This patch aims at optimising the memory allocation in cases, when
the members from the context structure are unused. So el1 system
register context must be omitted when lower EL is always x-EL2.
* "CTX_INCLUDE_EL2_REGS" is the internal build flag which gets set,
when SPD=spmd and SPMD_SPM_AT_SEL2=1 or ENABLE_RME=1.
It indicates, the system registers at EL2 are context switched for
the respective build configuration. Here, there is no need to save
and restore EL1 system registers, while x-EL2 is enabled.
Henceforth, this patch addresses this issue, by taking out the EL1
context at all possible places, while EL2 (CTX_INCLUDE_EL2_REGS) is
enabled, there by saving memory.
Change-Id: Ifddc497d3c810e22a15b1c227a731bcc133c2f4a
Signed-off-by: Jayanth Dodderi Chidanand <jayanthdodderi.chidanand@arm.com>
SCTLR_EL1 and TCR_EL1 regs are included either as part of errata
"ERRATA_SPECULATIVE_AT" or under el1_sysregs_t context structure.
The code to write and read into these context entries, looks
repetitive and is invoked at most places.
This section is refactored to bring them under a static procedure,
keeping the code neat and easier to maintain.
Change-Id: Ib0d8c51bee09e1600c5baaa7f9745083dca9fee1
Signed-off-by: Jayanth Dodderi Chidanand <jayanthdodderi.chidanand@arm.com>
* changes:
feat(fvp): allow SIMD context to be put in TZC DRAM
docs(simd): introduce CTX_INCLUDE_SVE_REGS build flag
feat(fvp): add Cactus partition manifest for EL3 SPMC
chore(simd): remove unused macros and utilities for FP
feat(el3-spmc): support simd context management upon world switch
feat(trusty): switch to simd_ctx_save/restore apis
feat(pncd): switch to simd_ctx_save/restore apis
feat(spm-mm): switch to simd_ctx_save/restore APIs
feat(simd): add rules to rationalize simd ctxt mgmt
feat(simd): introduce simd context helper APIs
feat(simd): add routines to save, restore sve state
feat(simd): add sve state to simd ctxt struct
feat(simd): add data struct for simd ctxt management
This adds assembly routines to save and restore SVE registers. In order
to share between FPU and SVE the code to save and restore FPCR and
FPSR, the patch converts code for those registers into macro.
Since we will be using simd_ctx_t to save and restore FPU also, we use
offsets in simd_ctx_t for FPSR and FPCR. Since simd_ctx_t has the same
structure at the beginning as fp_regs_t, those offsets should be the
same as CTX_FP_* offsets, when SVE is not enabled. Note that the code
also saves and restores FPEXC32 reg along with FPSR and FPCR.
Signed-off-by: Madhukar Pappireddy <madhukar.pappireddy@arm.com>
Signed-off-by: Okash Khawaja <okash@google.com>
Change-Id: I120c02359794aa6bb6376a464a9afe98bd84ae60
This patch checks if the Errata 2938996(Cortex-A520) , 2726228(Cortex-X4)
applies to cores and if affected applies the errata workaround which
disables TRBE.
Signed-off-by: Arvind Ram Prakash <arvind.ramprakash@arm.com>
Change-Id: I53b037839820c8b3a869f393588302a365d5b97c
With introduction of FEAT_STATE_CHECK_ASYMMETRIC, the asymmetry of cores
can be handled. SPE is one of the features which can be asymmetric
across cores.
Add a function to handle this asymmetry by re-visting the feature
presence on running core.
There are two possible cases:
- If the primary has the feature and secondary does not have it then,
the feature needs to be disabled.
- If the primary does not have the feature and secondary has it then,
the feature need to be enabled
Signed-off-by: Manish Pandey <manish.pandey2@arm.com>
Change-Id: Ibb2b88b5ef63b3efcb80801898ae8d8967e5c271
TF-A assumes that all the cores in a platform has architecture feature
parity, this is evident by the fact that primary sets up the
Non-secure context of secondary cores.
With changing landscape of platforms (e.g. big/little/mid cores), we are
seeing more and more platforms which has feature asymmetry among cores.
There is also a scenario where certain CPU erratum only applies to one
type of cores and requires a feature to be disabled even it supports
the feature.
To handle these scenarios, introduce a hook in warmboot path which would
be called on the running CPU to override any feature disparity in the
NS context stashed up by primary. Note that, re-checking of feature for
Secure/Realm context is not required as the context is created on
running core itself.
Signed-off-by: Manish Pandey <manish.pandey2@arm.com>
Change-Id: I5a01dbda528fa8481a00fdd098b58a7463ed0e22
Introduce a new feature state CHECK_ASYMMETRIC to cater for the features
which are asymmetric across cores. This state is useful for platforms
which has architectural asymmetric cores (A feature is only present in
one type of core e.g. big).
This state is similar to FEAT_STATE_CHECK (dynamic detection) except
that feature state is also checked on each core during warmboot path and
override the context (just for asymmetric features) which was setup by
core executing CPU_ON call.
Only Non-secure context will be re-checked as secure and realm context
is created on same core.
Signed-off-by: Manish Pandey <manish.pandey2@arm.com>
Change-Id: Ic78a0b6ca996e0d7881c43da1a6a0c422f528ef3
Currently the EL1 part of the context structure (el1_sysregs_t),
is coupled with feature flags reducing the context memory allocation
for platforms, that don't enable/support all the architectural
features at once.
Similar to the el2 context optimization commit-"d6af234" this patch
further improves this section by converting the assembly context-offset
entries into a c structure. It relies on garbage collection of the
linker removing unreferenced structures from memory, as well as aiding
in readability and future maintenance. Additionally, it eliminates
the #ifs usage in 'context_mgmt.c' source file.
Change-Id: If6075931cec994bc89231241337eccc7042c5ede
Signed-off-by: Jayanth Dodderi Chidanand <jayanthdodderi.chidanand@arm.com>
* Currently, "ERRATA_SPECUALTIVE_AT" errata is enabled by default
for few cores and they need context entries for saving and
restoring EL1 regs "SCTLR_EL1 and TCR_EL1" registers at all times.
* This prevents the mechanism of decoupling EL1 and EL2 registers,
as EL3 firmware shouldn't be handling both simultaneously.
* Depending on the build configuration either EL1 or EL2 context
structures need to included, which would result in saving a good
amount of context memory.
* In order to achieve this it's essential to have explicit context
entries for registers supporting "ERRATA_SPECULATIVE_AT".
* This patch adds two context entries under "errata_speculative_at"
structure to assist this errata and thereby allows decoupling
EL1 and EL2 context structures.
Change-Id: Ia50626eea8fb64899a2e2d81622adbe07fe77d65
Signed-off-by: Jayanth Dodderi Chidanand <jayanthdodderi.chidanand@arm.com>
The system register actlr_el2 can be set during CPU or platform reset
handler. E.g. on Arm Total Compute platform, the CLUSTERPMUEN bit of
actlr_el2 is set in the platform reset handler to enable the write
access to DSU PMU registers from EL1. However, as EL2 context gets
restored without saving it beforehand during jump to SPM and next NS
image, therefore, the initialized value of actlr_el2 is not retained.
To fix this issue, keep track of actlr_el2 value during the EL2 context
initialization. This applies for both secure and non-secure security
state.
Change-Id: I1bd7b984216c042c056ad20c6724bedce5a6a3e2
Signed-off-by: Jagdish Gediya <jagdish.gediya@arm.com>
Signed-off-by: Leo Yan <leo.yan@arm.com>
This patch disables trapping to EL3 when the FEAT_FGT2
specific trap registers are accessed by setting the
SCR_EL3.FGTEn2 bit
Signed-off-by: Arvind Ram Prakash <arvind.ramprakash@arm.com>
Change-Id: I6d2b614affb9067b2bc3d7bf0ae7d169d031592a
This patch enables FEAT_Debugv8p9 and prevents EL1/0 from
trapping to EL3 when accessing MDSELR_EL1 register by
setting the MDCR_EL3.EBWE bit.
Signed-off-by: Arvind Ram Prakash <arvind.ramprakash@arm.com>
Change-Id: I3613af1dd8cb8c0d3c33dc959f170846c0b9695a
Currently MDCR_EL3 register value is same for all the
worlds(Non-secure, Secure, Realm and Root).
With this approach, features enable/disable settings
remain same across all the worlds. This is not ideal as
there must be flexibility in controlling feature as per
the requirements for individual world.
The patch addresses this by providing MDCR_EL3 a per world
value. Features with identical values for all the worlds are
grouped under ``manage_extensions_common`` API.
Change-Id: Ibc068d985fe165d8cb6d0ffb84119bffd743b3d1
Signed-off-by: Jayanth Dodderi Chidanand <jayanthdodderi.chidanand@arm.com>
Currently, during the initial bootup phase SCTLR_EL2 register
has been initialised with the endianness bit based on header
attribute evaluation at EL3.
This is not mandatorily required as TF-A by default, expects
the software at EL2 to execute in little endian format ( EE = 0).
Henceforth, this patch removes the endianness bit evaluation for
SCTLR_EL2 register and initialises with a predefined RESET value,
setting SCTLR_EL2.EE=0.
Change-Id: I53fdd5bf907cbe35c551fc03cc893821229ff807
Signed-off-by: Jayanth Dodderi Chidanand <jayanthdodderi.chidanand@arm.com>
* FEAT_MPAM related EL2 registers are placed explicitly outside
the EL2 context in the cpu_context_t structure.
* With EL2 registers now coupled with dependent features, this
patch moves them to the el2_context structure "el2_sysregs_t".
* Further, converting the assembly context-offset entries into a
c structure. It relies on garbage collection of the linker
removing unreferenced structures from memory, as well as aiding
in readability and future maintenance.
Change-Id: Ib784bc8d2fbe35a8a47a569426d8663282ec06aa
Signed-off-by: Jayanth Dodderi Chidanand <jayanthdodderi.chidanand@arm.com>
The following system registers are made part of save and restore
operations for EL1 context:
TRFCR_EL1
SCXTNUM_EL0
SCXTNUM_EL1
GCSCR_EL1
GCSCRE0_EL1
GCSPR_EL1
GCSPR_EL0
Change-Id: I1077112bdc29a6c9cd39b9707d6cf10b95fa15e3
Signed-off-by: Madhukar Pappireddy <madhukar.pappireddy@arm.com>
* changes:
fix(bl1): add missing `__RW_{START,END}__` symbols
fix(fvp): don't check MPIDRs with the power controller in BL1
fix(arm): only expose `arm_bl2_dyn_cfg_init` to BL2
fix(cm): hide `cm_init_context_by_index` from BL1
fix(bl1): add missing spinlock dependency
commit@c282384dbb45b6185b4aba14efebbad110d18e49
removed ENABLE_FEAT_MTE but missed its usage in
context structure declaration path.
All mte regs that are currently context saved/restored
are needed only when FEAT_MTE2 is enabled, so move to
usage of FEAT_MTE2 and remove FEAT_MTE usage
Change-Id: I6b4417485fa6b7f52a31045562600945e48e81b7
Signed-off-by: Jayanth Dodderi Chidanand <jayanthdodderi.chidanand@arm.com>
BL1 requires the context management library but does not use or
implement `cm_init_context_by_index`. This change ensures that is not
compiled into BL1, as linking with LTO enabled causes an undefined
reference for this function.
Change-Id: I4a4602843bd75bc4f47b3e0c4c5a6efce1514ef6
Signed-off-by: Chris Kay <chris.kay@arm.com>
The following system registers are made part of save and restore
operations for EL1 context:
MDCCINT_EL1
MDSCR_EL1
DISR_EL1
PIRE0_EL1
PIR_EL1
POR_EL1
S2POR_EL1
TCR2_EL1
Some of these registers are available as part of core Armv8-A
architecture while others are made available through various
architectural extensions.
Change-Id: I507dccb9053ba177e1b98100fceccd1f32bdfc5c
Signed-off-by: Madhukar Pappireddy <madhukar.pappireddy@arm.com>
This patch fixes a typo which led to incorrect context save
operations for two FEAT_GCS registers.
Change-Id: I3d3202a6721714bbc8f84c2d775d1b28afffa5df
Signed-off-by: Madhukar Pappireddy <madhukar.pappireddy@arm.com>
Currently both FEAT_MTE and FEAT_MTE_PERM aren't used for enabling
of any feature bits in EL3. So remove both FEAT handling.
All mte regs that are currently context saved/restored are needed
only when FEAT_MTE2 is enabled, so move to usage of FEAT_MTE2 and
remove FEAT_MTE usage.
BREAKING CHANGE: Any platform or downstream code trying to use
SCR_EL3.ATA bit(26) will see failures as this is now moved to be
used only with FEAT_MTE2 with
commit@ef0d0e5478a3f19cbe70a378b9b184036db38fe2
Change-Id: Id01e154156571f7792135639e17dc5c8d0e17cf8
Signed-off-by: Govindraj Raja <govindraj.raja@arm.com>
This patch covers the following:
* Conditions set for verifying the EL2 presence and its usage
for various scenarios while exiting to Non secure world
"cm_prepare_el3_exit" has been improved.
* It thereby also fixes the issue(misra_c_2012_rule_15_7_violation)
for not terminating "if..else if" construct with an else statement
and keeps code in accordance with MISRA standards.
Change-Id: Ie5284447f5ac91412552629b76dbf2e636a09fd9
Signed-off-by: Jayanth Dodderi Chidanand <jayanthdodderi.chidanand@arm.com>
Currently the EL2 part of the context structure (el2_sysregs_t), is
mostly feature dependent.
For instance, CTX_HCRX_EL2 is only needed when FEAT_HCX
(ENABLE_FEAT_HCX=1) is set, but the entry is unconditionally added
in the EL2 context structure and thereby consuming memory even in
build configurations where FEAT_HCX is disabled.
Henceforth, all such context entries should be coupled/tied with
their respective feature enables and be optimized away when unused.
This would reduce the context memory allocation for platforms, that
dont enable/support all the architectural features at once.
Further, converting the assembly context-offset entries into
a c structure relies on garbage collection of the linker
removing unreferenced structures from memory, as well as aiding
in readability and future maintenance.
Change-Id: I0cf49498ee3033cb6f3ee3810331121b26627783
Signed-off-by: Jayanth Dodderi Chidanand <jayanthdodderi.chidanand@arm.com>
Similar to the refactoring process followed for EL2 system registers,
moving the save and restore routines of EL1 system registers into C
file, thereby reducing assembly code.
Change-Id: Ib59fbbe2eef2aa815effe854cf962fc4ac62a2ae
Signed-off-by: Jayanth Dodderi Chidanand <jayanthdodderi.chidanand@arm.com>
This patch does following two changes
- Create a separate routine for saving/restoring GIC el2 system registers
- To access ICC_SRE_EL2 register there was a workaround to set
SCR_EL3.NS before accessing it. This was required because SCR_EL3.EEL2
was zero. But with commit f105dd5fa this bit has been set to one early
on in booting process for a system with FEAT_SEL2 present and S-EL2
enabled.
However, we still need the workaround for a system which needs
save/restore of EL2 registers without secure EL2 being enabled e.g.
system with Non-secure and Realm world present.
Signed-off-by: Manish Pandey <manish.pandey2@arm.com>
Change-Id: I8d55c3dc6a17c4749748822d4a738912c1e13298
Add support for feat mte2. tfsr_el2 is available only with mte2,
however currently its context_save/restore is done with mte rather than
mte2, so introduce 'is_feat_mte2_supported' to check mte2.
Change-Id: I108d9989a8f5b4d1d2f3b9865a914056fa566cf2
Signed-off-by: Govindraj Raja <govindraj.raja@arm.com>
This feature provides support to context save the
SCXTNUM_ELx register. FEAT_CSV2_3 implies the implementation
of FEAT_CSV2_2. FEAT_CSV2_3 is supported in AArch64 state only
and is an optional feature in Arm v8.0 implementations.
This patch adds feature detection for v8.9 feature FEAT_CSV2_3,
adds macros for ID_AA64PFR0_EL1.CSV2 bits [59:56] for detecting
FEAT_CSV2_3 and macro for ENABLE_FEAT_CSV2_3.
Change-Id: Ida9f31e832b5f11bd89eebd6cc9f10ddad755c14
Signed-off-by: Sona Mathew <sonarebecca.mathew@arm.com>
commit@0a33adc058080433f73bde73895266068990245c
Deprecated CTX_INCLUDE_MTE_REGS but missed its usage in
context save and restore path.
Change-Id: I30544abdff2cf92ff05d2d4df46ffc6ff10611de
Signed-off-by: Govindraj Raja <govindraj.raja@arm.com>
Currently CTX_INCLUDE_MTE_REGS is used for dual purpose,
to enable allocation tags register and to context save and restore
them and also to check if mte feature is available.
To make it more meaningful, remove CTX_INCLUDE_MTE_REGS
and introduce FEAT_MTE. This would enable allocation tags register
when FEAT_MTE is enabled and also supported from platform.
Also arch features can be conditionally enabled disabled based on
arch version from `make_helpers/arch_features.mk`
Change-Id: Ibdd2d43874634ad7ddff93c7edad6044ae1631ed
Signed-off-by: Govindraj Raja <govindraj.raja@arm.com>
This patch provides a reporting functionality to display the memory
consumed by the context in each security state and for each exception
level. Flag PLATFORM_REPORT_CTX_MEM_USE enables or disables this
feature.
Change-Id: I1515366bf87561dcedf2b3206be167804df681d4
Signed-off-by: Juan Pablo Conde <juanpablo.conde@arm.com>
Signed-off-by: Jayanth Dodderi Chidanand <jayanthdodderi.chidanand@arm.com>
New build option CTX_INCLUDE_MPAM_REGS is added to select
if the firmware needs to save the MPAM EL2 registers during world
switches. This option is currently disabled as MPAM is only
enabled for NS world.
Signed-off-by: Arvind Ram Prakash <arvind.ramprakash@arm.com>
Change-Id: Ie2e5e184cdb65f7e1a98d8fe81590253fd859679
Currently, the registers which are maintained per-world, does not
take into account the reset value while configuring the context for
the respective world.
This leads to an issue, wherein the register retains the same value
across world switch, which is an error.
This patch addresses this problem, by configuring the register
(cptr_el3) precisely according to the world, the cpu is in
execution via resetting it before initializing the world specific context.
Change-Id: I592d82af373155fca67eed109c199341c305f0b9
Signed-off-by: Jayanth Dodderi Chidanand <jayanthdodderi.chidanand@arm.com>
Introducing INIT_UNUSED_NS_EL2 macro which guards the code that
disables the unused EL2 when a platform hands off from EL3
to NS-EL1 instead of NS-EL2. Platforms without NS-EL2 in use
must enable this flag.
BREAKING CHANGE: Initialisation code for handoff from EL3 to NS-EL1
disabled by default. Platforms which do that need to enable this macro
going forward
Signed-off-by: Arvind Ram Prakash <arvind.ramprakash@arm.com>
Change-Id: I61431cc4f7e2feb568d472828e5fd79cc73e51f5
For synchronization of errors at exception boundries TF-A uses "esb"
instruction with FEAT_RAS or "dsb" and "isb" otherwise. The problem
with esb instruction is, along with synching errors it might also
consume the error, which is not ideal in all scenarios. On the other
hand we can't use dsb always as its in the hot path.
To solve above mentioned problem the best way is to use FEAT_IESB
feature which provides controls to insert an implicit Error
synchronization event at exception entry and exception return.
Assumption in TF-A is, if RAS Extension is present then FEAT_IESB will
also be present and enabled.
Signed-off-by: Manish Pandey <manish.pandey2@arm.com>
Change-Id: Ie5861eec5da4028a116406bb4d1fea7dac232456
Vector entries in EL3 from lower ELs, first check for any pending
async EAs from lower EL before handling the original exception.
This happens when there is an error (EA) in the system which is not
yet signaled to PE while executing at lower EL. During entry into EL3
the errors (EA) are synchronized causing async EA to pend at EL3.
On detecting the pending EA (via ISR_EL1.A) EL3 either reflects it back
to lower EL (KFH) or handles it in EL3 (FFH) based on EA routing model.
In case of Firmware First handling mode (FFH), EL3 handles the pended
EA first before returing back to handle the original exception.
While in case of Kernel First handling mode (KFH), EL3 will return back
to lower EL without handling the original exception. On returing to
lower EL, EA will be pended. In KFH mode there is a risk of back and
forth between EL3 and lower EL if the EA is masked at lower EL or
priority of EA is lower than that of original exception. This is a
limitation in current architecture but can be solved in future if EL3
gets a capability to inject virtual SError.
Signed-off-by: Manish Pandey <manish.pandey2@arm.com>
Change-Id: I3a2a31de7cf454d9d690b1ef769432a5b24f6c11
Currently, EL3 context registers are duplicated per-world per-cpu.
Some registers have the same value across all CPUs, so this patch
moves these registers out into a per-world context to reduce
memory usage.
Change-Id: I91294e3d5f4af21a58c23599af2bdbd2a747c54a
Signed-off-by: Elizabeth Ho <elizabeth.ho@arm.com>
Signed-off-by: Jayanth Dodderi Chidanand <jayanthdodderi.chidanand@arm.com>
Restricts MPAM to only NS world and enables trap to EL3 for access of
MPAM registers from lower ELs of Secure and Realm world.
This patch removes MPAM enablement from global context and adds it to
EL3 State context which enables/disables MPAM during world switches.
Renamed ENABLE_MPAM_FOR_LOWER_ELS to ENABLE_FEAT_MPAM and
removed mpam_init_el3() as RESET behaviour is trapping.
Signed-off-by: Arvind Ram Prakash <arvind.ramprakash@arm.com>
Change-Id: I131f9dba5df236a71959b2d425ee11af7f3c38c4
Currently, S-EL2 is being enabled specifically while we are in
secure context and gets toggled up when we exit secure world.
This behavior is not ideal and needs correction.
Enabling the S-EL2 via SCR_EL3.EEL2 register setting should be
global and this patch addresses it.
Change-Id: If6c39ca258f2fefa835c4b51e0f6b68165fd2e35
Signed-off-by: Jayanth Dodderi Chidanand <jayanthdodderi.chidanand@arm.com>
The EL2 context save/restore functions have an optimisation to not
bother with the EL2 context when SEL2 is not in use. However, this
decision is made on the current value of SCR_EL3.EEL2, which is not
the value for the selected security state, but rather, for the
security state that came before it. This relies on the EEL2 bit's
value to propagate identically to all worlds.
This has an unintended side effect that for the first entry into
secure world, the restoring of the context is fully skipped, because
SCR_EL3 is only initialized after the call to the restoring routine
which means the EEL2 bit is not initialized (except when FEAT_RME
is present). This is inconsistent with normal and realm worlds which
always get their EL2 registers zeroed.
Remove this optimization to remove all the complexity with managing
the EEL2 bit's value. Instead unconditionally save/restore all
registers. It is worth noting that there is no performance penalty
in the case where SEL2 is empty with this change. This is because
SEL2 will never be entered, and as such no secure save/restore will
happen anyway, while normal world remains unchanged.
Removing the value management of the EEL2 bit causes the
CTX_ICC_SRE_EL2 register to be inaccessible in Secure world for some
configurations.
Make the SCR_EL3.NS workaround in cm_prepare_el3_exit_ns() generic
on every access to the register.
Signed-off-by: Boyan Karatotev <boyan.karatotev@arm.com>
Change-Id: I1f56d85814c5897b468e82d4bd4a08e3a90a7f8f
