Previously mem_protect used to be only supported from BL2. This is not
helpful in the case when ARM TF-A BL2 is not used. This patch demonstrates
mem_protect from el3_runtime firmware on ARM Platforms specifically
when RESET_TO_BL31 or RESET_TO_SP_MIN flag is set as BL2 may be absent
in these cases. The Non secure DRAM is dynamically mapped into EL3 mmap
tables temporarily and then the protected regions are then cleared. This
avoids the need to map the non secure DRAM permanently to BL31/sp_min.
The stack size is also increased, because DYNAMIC_XLAT_TABLES require
a bigger stack.
Change-Id: Ia44c594192ed5c5adc596c0cff2c7cc18c001fde
Signed-off-by: Roberto Vargas <roberto.vargas@arm.com>
Since commit 031dbb1224 ("AArch32: Add essential Arch helpers"),
it is difficult to use consistent format strings for printf() family
between aarch32 and aarch64.
For example, uint64_t is defined as 'unsigned long long' for aarch32
and as 'unsigned long' for aarch64. Likewise, uintptr_t is defined
as 'unsigned int' for aarch32, and as 'unsigned long' for aarch64.
A problem typically arises when you use printf() in common code.
One solution could be, to cast the arguments to a type long enough
for both architectures. For example, if 'val' is uint64_t type,
like this:
printf("val = %llx\n", (unsigned long long)val);
Or, somebody may suggest to use a macro provided by <inttypes.h>,
like this:
printf("val = %" PRIx64 "\n", val);
But, both would make the code ugly.
The solution adopted in Linux kernel is to use the same typedefs for
all architectures. The fixed integer types in the kernel-space have
been unified into int-ll64, like follows:
typedef signed char int8_t;
typedef unsigned char uint8_t;
typedef signed short int16_t;
typedef unsigned short uint16_t;
typedef signed int int32_t;
typedef unsigned int uint32_t;
typedef signed long long int64_t;
typedef unsigned long long uint64_t;
[ Linux commit: 0c79a8e29b5fcbcbfd611daf9d500cfad8370fcf ]
This gets along with the codebase shared between 32 bit and 64 bit,
with the data model called ILP32, LP64, respectively.
The width for primitive types is defined as follows:
ILP32 LP64
int 32 32
long 32 64
long long 64 64
pointer 32 64
'long long' is 64 bit for both, so it is used for defining uint64_t.
'long' has the same width as pointer, so for uintptr_t.
We still need an ifdef conditional for (s)size_t.
All 64 bit architectures use "unsigned long" size_t, and most 32 bit
architectures use "unsigned int" size_t. H8/300, S/390 are known as
exceptions; they use "unsigned long" size_t despite their architecture
is 32 bit.
One idea for simplification might be to define size_t as 'unsigned long'
across architectures, then forbid the use of "%z" string format.
However, this would cause a distortion between size_t and sizeof()
operator. We have unknowledge about the native type of sizeof(), so
we need a guess of it anyway. I want the following formula to always
return 1:
__builtin_types_compatible_p(size_t, typeof(sizeof(int)))
Fortunately, ARM is probably a majority case. As far as I know, all
32 bit ARM compilers use "unsigned int" size_t.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
u_register_t is preferred rather than uint64_t. This is more
consistent with the aarch32 implementation.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
According to the ARMv8 ARM issue C.a:
AP[1] is valid only for stage 1 of a translation regime that can
support two VA ranges. It is RES 1 when stage 1 translations can
support only one VA range.
This means that, even though this bit is ignored, it should be set to 1
in the EL3 and EL2 translation regimes.
For translation regimes consisting on EL0 and a higher regime this bit
selects between control at EL0 or at the higher Exception level. The
regimes that support two VA ranges are EL1&0 and EL2&0 (the later one
is only available since ARMv8.1).
This fix has to be applied to both versions of the translation tables
library.
Change-Id: If19aaf588551bac7aeb6e9a686cf0c2068e7c181
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
Due to differences in the bitfields of the SMC IDs, it is not possible
to support SMCCC 1.X and 2.0 at the same time.
The behaviour of `SMCCC_MAJOR_VERSION` has changed. Now, it is a build
option that specifies the major version of the SMCCC that the Trusted
Firmware supports. The only two allowed values are 1 and 2, and it
defaults to 1. The value of `SMCCC_MINOR_VERSION` is derived from it.
Note: Support for SMCCC v2.0 is an experimental feature to enable
prototyping of secure partition specifications. Support for this
convention is disabled by default and could be removed without notice.
Change-Id: I88abf9ccf08e9c66a13ce55c890edea54d9f16a7
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
A fix for errata 843419 may be available in revision r0p4 of the
Cortex-A53 processor. The presence of the fix is determined by checking
bit 8 in the REVIDR register.
If the fix is present we report ERRATA_NOT_APPLIES which silences the
erroneous 'missing workaround' warning.
Change-Id: Ibd2a478df3e2a6325442a6a48a0bb0259dcfc1d7
Signed-off-by: Jonathan Wright <jonathan.wright@arm.com>
Void pointers have been used to access linker symbols, by declaring an
extern pointer, then taking the address of it. This limits symbols
values to aligned pointer values. To remove this restriction an
IMPORT_SYM macro has been introduced, which declares it as a char
pointer and casts it to the required type.
Change-Id: I89877fc3b13ed311817bb8ba79d4872b89bfd3b0
Signed-off-by: Joel Hutton <Joel.Hutton@Arm.com>
When the source code says 'SMCC' it is talking about the SMC Calling
Convention. The correct acronym is SMCCC. This affects a few definitions
and file names.
Some files have been renamed (smcc.h, smcc_helpers.h and smcc_macros.S)
but the old files have been kept for compatibility, they include the
new ones with an ERROR_DEPRECATED guard.
Change-Id: I78f94052a502436fdd97ca32c0fe86bd58173f2f
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
When querying `SMCCC_ARCH_WORKAROUND_1` through `SMCCC_ARCH_FEATURES`,
return either:
* -1 to indicate the PE on which `SMCCC_ARCH_FEATURES` is called
requires firmware mitigation for CVE-2017-5715 but the mitigation
is not compiled in.
* 0 to indicate that firmware mitigation is required, or
* 1 to indicate that no firmware mitigation is required.
This patch complies with v1.2 of the firmware interfaces
specification (ARM DEN 0070A).
Change-Id: Ibc32d6620efdac6c340758ec502d95554a55f02a
Signed-off-by: Dimitris Papastamos <dimitris.papastamos@arm.com>
If the CSV2 field reads as 1 then branch targets trained in one
context cannot affect speculative execution in a different context.
In that case skip the workaround on Cortex A72 and A73.
Change-Id: Ide24fb6efc77c548e4296295adc38dca87d042ee
Signed-off-by: Dimitris Papastamos <dimitris.papastamos@arm.com>
Rule 8.4: A compatible declaration shall be visible when
an object or function with external linkage is defined
Fixed for:
make DEBUG=1 PLAT=fvp LOG_LEVEL=50 all
Change-Id: I7c2ad3f5c015411c202605851240d5347e4cc8c7
Signed-off-by: Roberto Vargas <roberto.vargas@arm.com>
Rule 8.4: A compatible declaration shall be visible when
an object or function with external linkage is defined.
Change-Id: I26e042cb251a6f9590afa1340fdac73e42f23979
Signed-off-by: Roberto Vargas <roberto.vargas@arm.com>
Rule 8.3: All declarations of an object or function shall
use the same names and type qualifiers.
Change-Id: Iff384187c74a598a4e73f350a1893b60e9d16cec
Signed-off-by: Roberto Vargas <roberto.vargas@arm.com>
MISRA C-2012 Rule 7.3 violation: lowercase l shall not be used as literal suffixes.
This patch resolves this for the ULL() macro by using ULL suffix instead
of the ull suffix.
Change-Id: Ia8183c399e74677e676956e8653e82375d0e0a01
Signed-off-by: David Cunado <david.cunado@arm.com>
This patch also fixes the assumption that the counters are disabled on
the resume path. This is incorrect as the AMU counters are enabled
early in the CPU reset function before `cpuamu_context_restore()`
runs.
Change-Id: I38a94eb166a523f00de18e86860434ffccff2131
Signed-off-by: Dimitris Papastamos <dimitris.papastamos@arm.com>
This patch also fixes `cpuamu_write_cpuamcntenclr_el0()` to use an MSR
instruction instead of an MRS instruction.
Change-Id: Ia6531f64b5ebc60ba432124eaa8d8eaccba40ed0
Signed-off-by: Dimitris Papastamos <dimitris.papastamos@arm.com>
Implement helpers to test if the core supports SPE/SVE. We have a
similar helper for AMU and this patch makes all extensions consistent
in their implementation.
Change-Id: I3e6f7522535ca358259ad142550b19fcb883ca67
Signed-off-by: Dimitris Papastamos <dimitris.papastamos@arm.com>
When the MMU is enabled and the translation tables are mapped, data
read/writes to the translation tables are made using the attributes
specified in the translation tables themselves. However, the MMU
performs table walks with the attributes specified in TCR_ELx. They are
completely independent, so special care has to be taken to make sure
that they are the same.
This has to be done manually because it is not practical to have a test
in the code. Such a test would need to know the virtual memory region
that contains the translation tables and check that for all of the
tables the attributes match the ones in TCR_ELx. As the tables may not
even be mapped at all, this isn't a test that can be made generic.
The flags used by enable_mmu_xxx() have been moved to the same header
where the functions are.
Also, some comments in the linker scripts related to the translation
tables have been fixed.
Change-Id: I1754768bffdae75f53561b1c4a5baf043b45a304
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
According to the SMC Calling Convention (ARM DEN0028B):
The Unknown SMC Function Identifier is a sign-extended value of
(-1) that is returned in R0, W0 or X0 register.
The value wasn't sign-extended because it was defined as a 32-bit
unsigned value (0xFFFFFFFF).
SMC_PREEMPT has been redefined as -2 for the same reason.
NOTE: This might be a compatibility break for some AArch64 platforms
that don't follow the previous version of the SMCCC (ARM DEN0028A)
correctly. That document specifies that only the bottom 32 bits of the
returned value must be checked. If a platform relies on the top 32 bits
of the result being 0 (so that SMC_UNK is 0x00000000FFFFFFFF), it will
have to fix its code to comply with the SMCCC.
Change-Id: I7f7b109f6b30c114fe570aa0ead3c335383cb54d
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
This commit adds some more files to use zlib from TF.
To use zlib, ->zalloc and ->zfree hooks are needed. The implementation
depends on the system. For user-space, the libc provides malloc() and
friends. Unfortunately, ARM Trusted Firmware does not provide malloc()
or any concept of dynamic memory allocation.
I implemented very simple calloc() and free() for this. Stupidly,
zfree() never frees memory, but it works enough for this.
The purpose of using zlib is to implement gunzip() - this function
takes compressed data from in_buf, then dumps the decompressed data
to oub_buf. The work_buf is used for memory allocation during the
decompress. Upon exit, it updates in_buf and out_buf. If successful,
in_buf points to the end of input data, out_buf to the end of the
decompressed data.
To use this feature, you need to do:
- include lib/zlib/zlib.mk from your platform.mk
- add $(ZLIB_SOURCES) to your BL*_SOURCES
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Add amu_context_save() and amu_context_restore() functions for aarch32
Change-Id: I4df83d447adeaa9d9f203e16dc5a919ffc04d87a
Signed-off-by: Joel Hutton <joel.hutton@arm.com>
In the initial implementation of this workaround we used a dedicated
workaround context to save/restore state. This patch reduces the
footprint as no additional context is needed.
Additionally, this patch reduces the memory loads and stores by 20%,
reduces the instruction count and exploits static branch prediction to
optimize the SMC path.
Change-Id: Ia9f6bf06fbf8a9037cfe7f1f1fb32e8aec38ec7d
Signed-off-by: Dimitris Papastamos <dimitris.papastamos@arm.com>
SMCCC v1.1 comes with a relaxed calling convention for AArch64
callers. The caller only needs to save x0-x3 before doing an SMC
call.
This patch adds support for SMCCC_VERSION and SMCCC_ARCH_FEATURES.
Refer to "Firmware Interfaces for mitigating CVE_2017_5715 System
Software on Arm Systems"[0] for more information.
[0] https://developer.arm.com/-/media/developer/pdf/ARM%20DEN%200070A%20Firmware%20interfaces%20for%20mitigating%20CVE-2017-5715_V1.0.pdf
Change-Id: If5b1c55c17d6c5c7cb9c2c3ed355d3a91cdad0a9
Signed-off-by: Dimitris Papastamos <dimitris.papastamos@arm.com>
The current div_round_up() implementation relies on round_up() which
only works correctly for boundaries that are a power of 2. It is
documented as such, but this still seems dangerously easy to overlook,
especially since many other environments (e.g. the Linux kernel) have a
similar macro without these limitations.
There is a different way to calculate this that can deal with all kinds
of divisors without other drawbacks, so let's just use that instead.
Change-Id: Id382736683f5d4e880ef00c53cfa23a2f9208440
Signed-off-by: Julius Werner <jwerner@chromium.org>
This patch adds the foundation for a platform-independent coreboot
support library that can be shared by all platforms that boot BL31 from
coreboot (acting as BL2). It adds code to parse the "coreboot table", a
data structure that coreboot uses to communicate different kinds of
information to later-stage firmware and certain OS drivers.
As a first small use case for this information, allow platforms to
access the serial console configuration used by coreboot, removing the
need to hardcode base address and divisors and allowing Trusted Firmware
to benefit from coreboot's user configuration (e.g. which UART to pick
and which baud rate to use).
Change-Id: I2bfb39cd2609ce6640b844ab68df6c9ae3f28e9e
Signed-off-by: Julius Werner <jwerner@chromium.org>
A per-cpu vbar is installed that implements the workaround by
invalidating the branch target buffer (BTB) directly in the case of A9
and A17 and indirectly by invalidating the icache in the case of A15.
For Cortex A57 and A72 there is currently no workaround implemented
when EL3 is in AArch32 mode so report it as missing.
For other vulnerable CPUs (e.g. Cortex A73 and Cortex A75), there are
no changes since there is currently no upstream AArch32 EL3 support
for these CPUs.
Change-Id: Ib42c6ef0b3c9ff2878a9e53839de497ff736258f
Signed-off-by: Dimitris Papastamos <dimitris.papastamos@arm.com>
This patch introduces two workarounds for ARMv7 systems. The
workarounds need to be applied prior to any `branch` instruction in
secure world. This is achieved using a custom vector table where each
entry is an `add sp, sp, #1` instruction.
On entry to monitor mode, once the sequence of `ADD` instructions is
executed, the branch target buffer (BTB) is invalidated. The bottom
bits of `SP` are then used to decode the exception entry type.
A side effect of this change is that the exception vectors are
installed before the CPU specific reset function. This is now
consistent with how it is done on AArch64.
Note, on AArch32 systems, the exception vectors are typically tightly
integrated with the secure payload (e.g. the Trusted OS). This
workaround will need porting to each secure payload that requires it.
The patch to modify the AArch32 per-cpu vbar to the corresponding
workaround vector table according to the CPU type will be done in a
later patch.
Change-Id: I5786872497d359e496ebe0757e8017fa98f753fa
Signed-off-by: Dimitris Papastamos <dimitris.papastamos@arm.com>
This patch enables BL2 to execute at the highest exception level
without any dependancy on TF BL1. This enables platforms which already
have a non-TF Boot ROM to directly load and execute BL2 and subsequent BL
stages without need for BL1. This is not currently possible because
BL2 executes at S-EL1 and cannot jump straight to EL3.
Change-Id: Ief1efca4598560b1b8c8e61fbe26d1f44e929d69
Signed-off-by: Roberto Vargas <roberto.vargas@arm.com>
typedef mem_region_t mem_region_t;
... seems to work because they belong to different name-spaces,
but humans are confused even if compilers are not.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
On some systems, the AMU counters might reset to 0 when a CPU
powerdown happens. This behaviour conflicts with the intended
use-case of AMU as lower ELs are only expected to see non-decreasing
counter values.
Change-Id: If25519965d4e6e47e09225d0e732947986cbb5ec
Signed-off-by: Dimitris Papastamos <dimitris.papastamos@arm.com>
Add some AMU helper functions to allow configuring, reading and
writing of the Group 0 and Group 1 counters. Documentation for these
helpers will come in a separate patch.
Change-Id: I656e070d2dae830c22414f694aa655341d4e2c40
Signed-off-by: Dimitris Papastamos <dimitris.papastamos@arm.com>
A new platform macro `PLAT_AMU_GROUP1_COUNTERS_MASK` controls which
group 1 counters should be enabled. The maximum number of group 1
counters supported by AMUv1 is 16 so the mask can be at most 0xffff.
If the platform does not define this mask, no group 1 counters are
enabled.
A related platform macro `PLAT_AMU_GROUP1_NR_COUNTERS` is used by
generic code to allocate an array to save and restore the counters on
CPU suspend.
Change-Id: I6d135badf4846292de931a43bb563077f42bb47b
Signed-off-by: Dimitris Papastamos <dimitris.papastamos@arm.com>
The suspend hook is published at the start of a CPU powerdown
operation. The resume hook is published at the end of a CPU powerup
operation.
Change-Id: I50c05e2dde0d33834095ac41b4fcea4c161bb434
Signed-off-by: Dimitris Papastamos <dimitris.papastamos@arm.com>
If the CSV2 field reads as 1 then branch targets trained in one
context cannot affect speculative execution in a different context.
In that case skip the workaround on Cortex A75.
Change-Id: I4d5504cba516a67311fb5f0657b08f72909cbd38
Signed-off-by: Dimitris Papastamos <dimitris.papastamos@arm.com>
Invalidate the Branch Target Buffer (BTB) on entry to EL3 by
temporarily dropping into AArch32 Secure-EL1 and executing the
`BPIALL` instruction.
This is achieved by using 3 vector tables. There is the runtime
vector table which is used to handle exceptions and 2 additional
tables which are required to implement this workaround. The
additional tables are `vbar0` and `vbar1`.
The sequence of events for handling a single exception is
as follows:
1) Install vector table `vbar0` which saves the CPU context on entry
to EL3 and sets up the Secure-EL1 context to execute in AArch32 mode
with the MMU disabled and I$ enabled. This is the default vector table.
2) Before doing an ERET into Secure-EL1, switch vbar to point to
another vector table `vbar1`. This is required to restore EL3 state
when returning from the workaround, before proceeding with normal EL3
exception handling.
3) While in Secure-EL1, the `BPIALL` instruction is executed and an
SMC call back to EL3 is performed.
4) On entry to EL3 from Secure-EL1, the saved context from step 1) is
restored. The vbar is switched to point to `vbar0` in preparation to
handle further exceptions. Finally a branch to the runtime vector
table entry is taken to complete the handling of the original
exception.
This workaround is enabled by default on the affected CPUs.
NOTE
====
There are 4 different stubs in Secure-EL1. Each stub corresponds to
an exception type such as Sync/IRQ/FIQ/SError. Each stub will move a
different value in `R0` before doing an SMC call back into EL3.
Without this piece of information it would not be possible to know
what the original exception type was as we cannot use `ESR_EL3` to
distinguish between IRQs and FIQs.
Change-Id: I90b32d14a3735290b48685d43c70c99daaa4b434
Signed-off-by: Dimitris Papastamos <dimitris.papastamos@arm.com>
In assembly code it can be useful to have a constant for the width of a
register in the current architecture, so this patch adds one to
<utils_def.h> and replaces the existing custom one in crash_reporting.S
with that. It also fixes up the BIT() macro in the same file so that it
can be safely used in assembly code.
Change-Id: I10513a311f3379e767396e6ddfbae8d2d8201464
Signed-off-by: Julius Werner <jwerner@chromium.org>
A new platform define, `PLAT_SP_IMAGE_XLAT_SECTION_NAME`, has been
introduced to select the section where the translation tables used by
the S-EL1/S-EL0 are placed.
This define has been used to move the translation tables to DRAM secured
by TrustZone.
Most of the extra needed space in BL31 when SPM is enabled is due to the
large size of the translation tables. By moving them to this memory
region we can save 44 KiB.
A new argument has been added to REGISTER_XLAT_CONTEXT2() to specify the
region where the translation tables have to be placed by the linker.
Change-Id: Ia81709b4227cb8c92601f0caf258f624c0467719
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
This patch adds a new build option, ENABLE_SVE_FOR_NS, which when set
to one EL3 will check to see if the Scalable Vector Extension (SVE) is
implemented when entering and exiting the Non-secure world.
If SVE is implemented, EL3 will do the following:
- Entry to Non-secure world: SIMD, FP and SVE functionality is enabled.
- Exit from Non-secure world: SIMD, FP and SVE functionality is
disabled. As SIMD and FP registers are part of the SVE Z-registers
then any use of SIMD / FP functionality would corrupt the SVE
registers.
The build option default is 1. The SVE functionality is only supported
on AArch64 and so the build option is set to zero when the target
archiecture is AArch32.
This build option is not compatible with the CTX_INCLUDE_FPREGS - an
assert will be raised on platforms where SVE is implemented and both
ENABLE_SVE_FOR_NS and CTX_INCLUDE_FPREGS are set to 1.
Also note this change prevents secure world use of FP&SIMD registers on
SVE-enabled platforms. Existing Secure-EL1 Payloads will not work on
such platforms unless ENABLE_SVE_FOR_NS is set to 0.
Additionally, on the first entry into the Non-secure world the SVE
functionality is enabled and the SVE Z-register length is set to the
maximum size allowed by the architecture. This includes the use case
where EL2 is implemented but not used.
Change-Id: Ie2d733ddaba0b9bef1d7c9765503155188fe7dae
Signed-off-by: David Cunado <david.cunado@arm.com>
The `ENABLE_AMU` build option can be used to enable the
architecturally defined AMU counters. At present, there is no support
for the auxiliary counter group.
Change-Id: Ifc7532ef836f83e629f2a146739ab61e75c4abc8
Signed-off-by: Dimitris Papastamos <dimitris.papastamos@arm.com>
The `ENABLE_AMU` build option can be used to enable the
architecturally defined AMU counters. At present, there is no support
for the auxiliary counter group.
Change-Id: I7ea0c0a00327f463199d1b0a481f01dadb09d312
Signed-off-by: Dimitris Papastamos <dimitris.papastamos@arm.com>
The Cortex A75 has 5 AMU counters. The first three counters are fixed
and the remaining two are programmable.
A new build option is introduced, `ENABLE_AMU`. When set, the fixed
counters will be enabled for use by lower ELs. The programmable
counters are currently disabled.
Change-Id: I4bd5208799bb9ed7d2596e8b0bfc87abbbe18740
Signed-off-by: Dimitris Papastamos <dimitris.papastamos@arm.com>
Factor out SPE operations in a separate file. Use the publish
subscribe framework to drain the SPE buffers before entering secure
world. Additionally, enable SPE before entering normal world.
A side effect of this change is that the profiling buffers are now
only drained when a transition from normal world to secure world
happens. Previously they were drained also on return from secure
world, which is unnecessary as SPE is not supported in S-EL1.
Change-Id: I17582c689b4b525770dbb6db098b3a0b5777b70a
Signed-off-by: Dimitris Papastamos <dimitris.papastamos@arm.com>
If an implementation of ARMv8.2 includes ARMv8.2-LPA, the value 0b0110
is permitted in ID_AA64MMFR0_EL1.PARange, which means that the Physical
Address range supported is 52 bits (4 PiB). It is a reserved value
otherwise.
Change-Id: Ie0147218e9650aa09f0034a9ee03c1cca8db908a
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
The FPEXC32_EL2 register controls SIMD and FP functionality when the
lower ELs are executing in AArch32 mode. It is architecturally mapped
to AArch32 system register FPEXC.
This patch removes FPEXC32_EL2 register from the System Register context
and adds it to the floating-point context. EL3 only saves / restores the
floating-point context if the build option CTX_INCLUDE_FPREGS is set to 1.
The rationale for this change is that if the Secure world is using FP
functionality and EL3 is not managing the FP context, then the Secure
world will save / restore the appropriate FP registers.
NOTE - this is a break in behaviour in the unlikely case that
CTX_INCLUDE_FPREGS is set to 0 and the platform contains an AArch32
Secure Payload that modifies FPEXC, but does not save and restore
this register
Change-Id: Iab80abcbfe302752d52b323b4abcc334b585c184
Signed-off-by: David Cunado <david.cunado@arm.com>