This fix modifies the order of system includes to meet the ARM TF coding
standard. There are some exceptions in order to retain header groupings,
minimise changes to imported headers, and where there are headers within
the #if and #ifndef statements.
Change-Id: I65085a142ba6a83792b26efb47df1329153f1624
Signed-off-by: Isla Mitchell <isla.mitchell@arm.com>
This patch adds `TRUSTED_BOARD_BOOT` support for AArch32 mode.
To build this patch the "mbedtls/include/mbedtls/bignum.h"
needs to be modified to remove `#define MBEDTLS_HAVE_UDBL`
when `MBEDTLS_HAVE_INT32` is defined. This is a workaround
for "https://github.com/ARMmbed/mbedtls/issues/708"
NOTE: TBBR support on Juno AArch32 is not currently supported.
Change-Id: I86d80e30b9139adc4d9663f112801ece42deafcf
Signed-off-by: dp-arm <dimitris.papastamos@arm.com>
Co-Authored-By: Yatharth Kochar <yatharth.kochar@arm.com>
To make software license auditing simpler, use SPDX[0] license
identifiers instead of duplicating the license text in every file.
NOTE: Files that have been imported by FreeBSD have not been modified.
[0]: https://spdx.org/
Change-Id: I80a00e1f641b8cc075ca5a95b10607ed9ed8761a
Signed-off-by: dp-arm <dimitris.papastamos@arm.com>
Many asserts depend on code that is conditionally compiled based on the
DEBUG define. This patch modifies the conditional inclusion of such code
so that it is based on the ENABLE_ASSERTIONS build option.
Change-Id: I6406674788aa7e1ad7c23d86ce94482ad3c382bd
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
Call console_flush() before execution either terminates or leaves an
exception level.
Fixes: ARM-software/tf-issues#123
Change-Id: I64eeb92effb039f76937ce89f877b68e355588e3
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
The errata reporting policy is as follows:
- If an errata workaround is enabled:
- If it applies (i.e. the CPU is affected by the errata), an INFO
message is printed, confirming that the errata workaround has been
applied.
- If it does not apply, a VERBOSE message is printed, confirming
that the errata workaround has been skipped.
- If an errata workaround is not enabled, but would have applied had
it been, a WARN message is printed, alerting that errata workaround
is missing.
The CPU errata messages are printed by both BL1 (primary CPU only) and
runtime firmware on debug builds, once for each CPU/errata combination.
Relevant output from Juno r1 console when ARM Trusted Firmware is built
with PLAT=juno LOG_LEVEL=50 DEBUG=1:
VERBOSE: BL1: cortex_a57: errata workaround for 806969 was not applied
VERBOSE: BL1: cortex_a57: errata workaround for 813420 was not applied
INFO: BL1: cortex_a57: errata workaround for disable_ldnp_overread was applied
WARNING: BL1: cortex_a57: errata workaround for 826974 was missing!
WARNING: BL1: cortex_a57: errata workaround for 826977 was missing!
WARNING: BL1: cortex_a57: errata workaround for 828024 was missing!
WARNING: BL1: cortex_a57: errata workaround for 829520 was missing!
WARNING: BL1: cortex_a57: errata workaround for 833471 was missing!
...
VERBOSE: BL31: cortex_a57: errata workaround for 806969 was not applied
VERBOSE: BL31: cortex_a57: errata workaround for 813420 was not applied
INFO: BL31: cortex_a57: errata workaround for disable_ldnp_overread was applied
WARNING: BL31: cortex_a57: errata workaround for 826974 was missing!
WARNING: BL31: cortex_a57: errata workaround for 826977 was missing!
WARNING: BL31: cortex_a57: errata workaround for 828024 was missing!
WARNING: BL31: cortex_a57: errata workaround for 829520 was missing!
WARNING: BL31: cortex_a57: errata workaround for 833471 was missing!
...
VERBOSE: BL31: cortex_a53: errata workaround for 826319 was not applied
INFO: BL31: cortex_a53: errata workaround for disable_non_temporal_hint was applied
Also update documentation.
Change-Id: Iccf059d3348adb876ca121cdf5207bdbbacf2aba
Signed-off-by: Jeenu Viswambharan <jeenu.viswambharan@arm.com>
This patch adds generic changes in BL1 to support AArch32 state.
New AArch32 specific assembly/C files are introduced and
some files are moved to AArch32/64 specific folders.
BL1 for AArch64 is refactored but functionally identical.
BL1 executes in Secure Monitor mode in AArch32 state.
NOTE: BL1 in AArch32 state ONLY handles BL1_RUN_IMAGE SMC.
Change-Id: I6e2296374c7efbf3cf2aa1a0ce8de0732d8c98a5
This patch adds changes in BL1 & BL2 to use new version
of image loading to load the BL images.
Following are the changes in BL1:
-Use new version of load_auth_image() to load BL2
-Modified `bl1_init_bl2_mem_layout()` to remove using
`reserve_mem()` and to calculate `bl2_mem_layout`.
`bl2_mem_layout` calculation now assumes that BL1 RW
data is at the top of the bl1_mem_layout, which is more
restrictive than the previous BL1 behaviour.
Following are the changes in BL2:
-The `bl2_main.c` is refactored and all the functions
for loading BLxx images are now moved to `bl2_image_load.c`
`bl2_main.c` now calls a top level `bl2_load_images()` to
load all the images that are applicable in BL2.
-Added new file `bl2_image_load_v2.c` that uses new version
of image loading to load the BL images in BL2.
All the above changes are conditionally compiled using the
`LOAD_IMAGE_V2` flag.
Change-Id: Ic6dcde5a484495bdc05526d9121c59fa50c1bf23
This patch moves the macro SIZE_FROM_LOG2_WORDS() defined in
`arch.h` to `utils.h` as it is utility macro.
Change-Id: Ia8171a226978f053a1ee4037f80142c0a4d21430
This patch removes the dash character from the image name, to
follow the image terminology in the Trusted Firmware Wiki page:
https://github.com/ARM-software/arm-trusted-firmware/wiki
Changes apply to output messages, comments and documentation.
non-ARM platform files have been left unmodified.
Change-Id: Ic2a99be4ed929d52afbeb27ac765ceffce46ed76
Firmware update(a.k.a FWU) feature is part of the TBB architecture.
BL1 is responsible for carrying out the FWU process if platform
specific code detects that it is needed.
This patch adds support for FWU feature support in BL1 which is
included by enabling `TRUSTED_BOARD_BOOT` compile time flag.
This patch adds bl1_fwu.c which contains all the core operations
of FWU, which are; SMC handler, image copy, authentication, execution
and resumption. It also adds bl1.h introducing #defines for all
BL1 SMCs.
Following platform porting functions are introduced:
int bl1_plat_mem_check(uintptr_t mem_base, unsigned int mem_size,
unsigned int flags);
This function can be used to add platform specific memory checks
for the provided base/size for the given security state.
The weak definition will invoke `assert()` and return -ENOMEM.
__dead2 void bl1_plat_fwu_done(void *cookie, void *reserved);
This function can be used to initiate platform specific procedure
to mark completion of the FWU process.
The weak definition waits forever calling `wfi()`.
plat_bl1_common.c contains weak definitions for above functions.
FWU process starts when platform detects it and return the image_id
other than BL2_IMAGE_ID by using `bl1_plat_get_next_image_id()` in
`bl1_main()`.
NOTE: User MUST provide platform specific real definition for
bl1_plat_mem_check() in order to use it for Firmware update.
Change-Id: Ice189a0885d9722d9e1dd03f76cac1aceb0e25ed
As of now BL1 loads and execute BL2 based on hard coded information
provided in BL1. But due to addition of support for upcoming Firmware
Update feature, BL1 now require more flexible approach to load and
run different images using information provided by the platform.
This patch adds new mechanism to load and execute images based on
platform provided image id's. BL1 now queries the platform to fetch
the image id of the next image to be loaded and executed. In order
to achieve this, a new struct image_desc_t was added which holds the
information about images, such as: ep_info and image_info.
This patch introduces following platform porting functions:
unsigned int bl1_plat_get_next_image_id(void);
This is used to identify the next image to be loaded
and executed by BL1.
struct image_desc *bl1_plat_get_image_desc(unsigned int image_id);
This is used to retrieve the image_desc for given image_id.
void bl1_plat_set_ep_info(unsigned int image_id,
struct entry_point_info *ep_info);
This function allows platforms to update ep_info for given
image_id.
The plat_bl1_common.c file provides default weak implementations of
all above functions, the `bl1_plat_get_image_desc()` always return
BL2 image descriptor, the `bl1_plat_get_next_image_id()` always return
BL2 image ID and `bl1_plat_set_ep_info()` is empty and just returns.
These functions gets compiled into all BL1 platforms by default.
Platform setup in BL1, using `bl1_platform_setup()`, is now done
_after_ the initialization of authentication module. This change
provides the opportunity to use authentication while doing the
platform setup in BL1.
In order to store secure/non-secure context, BL31 uses percpu_data[]
to store context pointer for each core. In case of BL1 only the
primary CPU will be active hence percpu_data[] is not required to
store the context pointer.
This patch introduce bl1_cpu_context[] and bl1_cpu_context_ptr[] to
store the context and context pointers respectively. It also also
re-defines cm_get_context() and cm_set_context() for BL1 in
bl1/bl1_context_mgmt.c.
BL1 now follows the BL31 pattern of using SP_EL0 for the C runtime
environment, to support resuming execution from a previously saved
context.
NOTE: THE `bl1_plat_set_bl2_ep_info()` PLATFORM PORTING FUNCTION IS
NO LONGER CALLED BY BL1 COMMON CODE. PLATFORMS THAT OVERRIDE
THIS FUNCTION MAY NEED TO IMPLEMENT `bl1_plat_set_ep_info()`
INSTEAD TO MAINTAIN EXISTING BEHAVIOUR.
Change-Id: Ieee4c124b951c2e9bc1c1013fa2073221195d881
The primary usage of `RUN_IMAGE` SMC function id, used by BL2 is to
make a request to BL1 to execute BL31. But BL2 also uses it as
opcode to check if it is allowed to execute which is not the
intended usage of `RUN_IMAGE` SMC.
This patch removes the usage of `RUN_IMAGE` as opcode passed to
next EL to check if it is allowed to execute.
Change-Id: I6aebe0415ade3f43401a4c8a323457f032673657
This patch introduces a new build flag, SPIN_ON_BL1_EXIT, which
puts an infinite loop in BL1. It is intended to help debugging
the post-BL2 phase of the Trusted Firmware by stopping execution
in BL1 just before handing over to BL31. At this point, the
developer may take control of the target using a debugger.
This feature is disabled by default and can be enabled by
rebuilding BL1 with SPIN_ON_BL1_EXIT=1.
User Guide updated accordingly.
Change-Id: I6b6779d5949c9e5571dd371255520ef1ac39685c
- Remove out-dated information about the use of printf() in the
function comment.
- Make the argument const, as the function doesn't need to modify it.
- Rename the function into bl1_print_bl31_ep_info() to make its
purpose clearer.
Change-Id: I2a9d215a37f0ec11aefce0c5c9e050473b7a6b25
This patch introduces a new function called 'print_entry_point_info'
that prints an entry_point_t structure for debugging purposes.
As such, it can be used to display the entry point address, SPSR and
arguments passed from a firmware image to the next one.
This function is now called in the following images transitions:
- BL1 to BL2
- BL1 to BL31
- BL31 to the next image (typically BL32 or BL33)
The following changes have been introduced:
- Fix the output format of the SPSR value : SPSR is a 32-bit value,
not a 64-bit one.
- Print all arguments values.
The entry_point_info_t structure allows to pass up to 8 arguments.
In most cases, only the first 2 arguments were printed.
print_entry_point_info() now prints all of them as 'VERBOSE'
traces.
Change-Id: Ieb384bffaa7849e6cb95a01a47c0b7fc2308653a
This patch adds an optional API to the platform port:
void plat_error_handler(int err) __dead2;
The platform error handler is called when there is a specific error
condition after which Trusted Firmware cannot continue. While panic()
simply prints the crash report (if enabled) and spins, the platform
error handler can be used to hand control over to the platform port
so it can perform specific bookeeping or post-error actions (for
example, reset the system). This function must not return.
The parameter indicates the type of error using standard codes from
errno.h. Possible errors reported by the generic code are:
-EAUTH : a certificate or image could not be authenticated
(when Trusted Board Boot is enabled)
-ENOENT : the requested image or certificate could not be found
or an IO error was detected
-ENOMEM : resources exhausted. Trusted Firmware does not use
dynamic memory, so this error is usually an indication
of an incorrect array size
A default weak implementation of this function has been provided.
It simply implements an infinite loop.
Change-Id: Iffaf9eee82d037da6caa43b3aed51df555e597a3
BL2 loads secure runtime code(BL3-1, BL3-2) and hence it has to
run in secure world otherwise BL3-1/BL3-2 have to execute from
non-secure memory. Hence, This patch removes the change_security_state()
call in bl1_run_bl2() and replaces it with an assert to confirm
the BL2 as secure.
FixesARM-software/tf-issues#314
Change-Id: I611b83f5c4090e58a76a2e950b0d797b46df3c29
This patch modifies the Trusted Board Boot implementation to use
the new authentication framework, making use of the authentication
module, the cryto module and the image parser module to
authenticate the images in the Chain of Trust.
A new function 'load_auth_image()' has been implemented. When TBB
is enabled, this function will call the authentication module to
authenticate parent images following the CoT up to the root of
trust to finally load and authenticate the requested image.
The platform is responsible for picking up the right makefiles to
build the corresponding cryptographic and image parser libraries.
ARM platforms use the mbedTLS based libraries.
The platform may also specify what key algorithm should be used
to sign the certificates. This is done by declaring the 'KEY_ALG'
variable in the platform makefile. FVP and Juno use ECDSA keys.
On ARM platforms, BL2 and BL1-RW regions have been increased 4KB
each to accommodate the ECDSA code.
REMOVED BUILD OPTIONS:
* 'AUTH_MOD'
Change-Id: I47d436589fc213a39edf5f5297bbd955f15ae867
The Trusted firmware code identifies BL images by name. The platform
port defines a name for each image e.g. the IO framework uses this
mechanism in the platform function plat_get_image_source(). For
a given image name, it returns the handle to the image file which
involves comparing images names. In addition, if the image is
packaged in a FIP, a name comparison is required to find the UUID
for the image. This method is not optimal.
This patch changes the interface between the generic and platform
code with regard to identifying images. The platform port must now
allocate a unique number (ID) for every image. The generic code will
use the image ID instead of the name to access its attributes.
As a result, the plat_get_image_source() function now takes an image
ID as an input parameter. The organisation of data structures within
the IO framework has been rationalised to use an image ID as an index
into an array which contains attributes of the image such as UUID and
name. This prevents the name comparisons.
A new type 'io_uuid_spec_t' has been introduced in the IO framework
to specify images identified by UUID (i.e. when the image is contained
in a FIP file). There is no longer need to maintain a look-up table
[iname_name --> uuid] in the io_fip driver code.
Because image names are no longer mandatory in the platform port, the
debug messages in the generic code will show the image identifier
instead of the file name. The platforms that support semihosting to
load images (i.e. FVP) must provide the file names as definitions
private to the platform.
The ARM platform ports and documentation have been updated accordingly.
All ARM platforms reuse the image IDs defined in the platform common
code. These IDs will be used to access other attributes of an image in
subsequent patches.
IMPORTANT: applying this patch breaks compatibility for platforms that
use TF BL1 or BL2 images or the image loading code. The platform port
must be updated to match the new interface.
Change-Id: I9c1b04cb1a0684c6ee65dee66146dd6731751ea5
The validation of the caching enable state in bl1_main() was
incorrect resulting in the state not being checked. Using the right
operator fixes this.
Change-Id: I2a99478f420281a1dcdf365d3d4fd8394cd21b51
The required platform constant PLATFORM_CACHE_LINE_SIZE is
unnecessary since CACHE_WRITEBACK_GRANULE effectively provides the
same information. CACHE_WRITEBACK_GRANULE is preferred since this
is an architecturally defined term and allows comparison with the
corresponding hardware register value.
Replace all usage of PLATFORM_CACHE_LINE_SIZE with
CACHE_WRITEBACK_GRANULE.
Also, add a runtime assert in BL1 to check that the provided
CACHE_WRITEBACK_GRANULE matches the value provided in CTR_EL0.
Change-Id: If87286be78068424217b9f3689be358356500dcd
This patch adds support to authenticate the BL2 content certificate
and image using the authentication module in BL1.
The FIP driver has been extended to include the BL2 certificate
UUID.
FVP and Juno ports include the BL2 certificate FIP file
definition.
Change-Id: I32680e9bd123c8db4a4193c14448c9b32b0e9325
Fix the following issues with the console log output:
* Make sure the welcome string is the first thing in the log output
(during normal boot).
* Prefix each message with the BL image name so it's clear which
BL the output is coming from.
* Ensure all output is wrapped in one of the log output macros so it can
be easily compiled out if necessary. Change some of the INFO() messages
to VERBOSE(), especially in the TSP.
* Create some extra NOTICE() and INFO() messages during cold boot.
* Remove all usage of \r in log output.
FixesARM-software/tf-issues#231
Change-Id: Ib24f7acb36ce64bbba549f204b9cde2dbb46c8a3
Print out Trusted Firmware version at runtime at each BL stage.
Message consists of TF version as defined statically in the Makefile
(e.g. v0.4), build mode (debug|release) and a customizable build
string:
1. By defining BUILD_STRING in command line when building TF
2. Default string is git commit ID
3. Empty if git meta-data is not available
FixesARM-software/tf-issues#203
Change-Id: I5c5ba438f66ab68810427d76b49c5b9177a957d6
This patch implements a "tf_printf" which supports only the commonly
used format specifiers in Trusted Firmware, which uses a lot less
stack space than the stdlib printf function.
FixesARM-software/tf-issues#116
Change-Id: I7dfa1944f4c1e634b3e2d571f49afe02d109a351
This concept is no longer required since we now support loading of
images at fixed addresses only.
The image loader now automatically detects the position of the image
inside the current memory layout and updates the layout such that
memory fragmentation is minimised.
The 'attr' field of the meminfo data structure, which used to hold
the bottom/top loading information, has been removed. Also the 'next'
field has been removed as it wasn't used anywhere.
The 'init_bl2_mem_layout()' function has been moved out of common
code and put in BL1-specific code. It has also been renamed into
'bl1_init_bl2_mem_layout'.
FixesARM-software/tf-issues#109
Change-Id: I3f54642ce7b763d5ee3b047ad0ab59eabbcf916d
Some platform porting functions were in BL specific header files.
These have been moved to platform.h so that all porting functions
are in the same place. The functions are now grouped by BL.
Obsolete BL headers files have been removed.
Also, the weak declaration of the init_bl2_mem_layout() function
has been moved out the header file and into the source file
(bl_common.c) using the more succinct #pragma syntax. This
mitigates the risk of 2 weak definitions being created and the
wrong one being picked up by the compiler.
Change-Id: Ib19934939fd755f3e5a5a5bceec88da684308a83
Previously, platform.h contained many declarations and definitions
used for different purposes. This file has been split so that:
* Platform definitions used by common code that must be defined
by the platform are now in platform_def.h. The exact include
path is exported through $PLAT_INCLUDES in the platform makefile.
* Platform definitions specific to the FVP platform are now in
/plat/fvp/fvp_def.h.
* Platform API declarations specific to the FVP platform are now
in /plat/fvp/fvp_private.h.
* The remaining platform API declarations that must be ported by
each platform are still in platform.h but this file has been
moved to /include/plat/common since this can be shared by all
platforms.
Change-Id: Ieb3bb22fbab3ee8027413c6b39a783534aee474a
This patch is based on spec published at
https://github.com/ARM-software/tf-issues/issues/133
It rearranges the bl31_args struct into
bl31_params and bl31_plat_params which provide the
information needed for Trusted firmware and platform
specific data via x0 and x1
On the FVP platform BL3-1 params and BL3-1 plat params
and its constituents are stored at the start of TZDRAM.
The information about memory availability and size for
BL3-1, BL3-2 and BL3-3 is moved into platform specific data.
Change-Id: I8b32057a3d0dd3968ea26c2541a0714177820da9
This patch reworks the handover interface from: BL1 to BL2 and
BL2 to BL3-1. It removes the raise_el(), change_el(), drop_el()
and run_image() functions as they catered for code paths that were
never exercised.
BL1 calls bl1_run_bl2() to jump into BL2 instead of doing the same
by calling run_image(). Similarly, BL2 issues the SMC to transfer
execution to BL3-1 through BL1 directly. Only x0 and x1 are used
to pass arguments to BL31. These arguments and parameters for
running BL3-1 are passed through a reference to a
'el_change_info_t' structure. They were being passed value in
general purpose registers earlier.
Change-Id: Id4fd019a19a9595de063766d4a66295a2c9307e1
This patch introduces macros (SPSR_64 and SPSR_32) to
create a SPSR for both aarch32 and aarch64 execution
states. These macros allow the user to set fields
in the SPSR depending upon its format.
The make_spsr() function which did not allow
manipulation of all the fields in the aarch32 SPSR
has been replaced by these new macros.
Change-Id: I9425dda0923e8d5f03d03ddb8fa0e28392c4c61e
Reduce the number of header files included from other header
files as much as possible without splitting the files. Use forward
declarations where possible. This allows removal of some unnecessary
"#ifndef __ASSEMBLY__" statements.
Also, review the .c and .S files for which header files really need
including and reorder the #include statements alphabetically.
FixesARM-software/tf-issues#31
Change-Id: Iec92fb976334c77453e010b60bcf56f3be72bd3e
Add tag names to all unnamed structs in header files. This
allows forward declaration of structs, which is necessary to
reduce header file nesting (to be implemented in a subsequent
commit).
Also change the typedef names across the codebase to use the _t
suffix to be more conformant with the Linux coding style. The
coding style actually prefers us not to use typedefs at all but
this is considered a step too far for Trusted Firmware.
Also change the IO framework structs defintions to use typedef'd
structs to be consistent with the rest of the codebase.
Change-Id: I722b2c86fc0d92e4da3b15e5cab20373dd26786f
Move the BL function prototypes out of arch.h and into the
appropriate header files to allow more efficient header file
inclusion. Create new BL private header files where there is no
sensible existing header file.
Change-Id: I45f3e10b72b5d835254a6f25a5e47cf4cfb274c3
Each ARM Trusted Firmware image should know in which EL it is running
and it should use the corresponding register directly instead of reading
currentEL and knowing which asm register to read/write
Change-Id: Ief35630190b6f07c8fbb7ba6cb20db308f002945
So it updates each time a bootloader changes, not just when bl*_main.c
files are recompiled.
FixesARM-software/tf-issues#33
Change-Id: Ie8e1a7bd7e1913d2e96ac268606284f76af8c5ab
Signed-off-by: Jon Medhurst <tixy@linaro.org>
This patch reworks BL2 to BL3-1 hand over interface by introducing a
composite structure (bl31_args) that holds the superset of information
that needs to be passed from BL2 to BL3-1.
- The extents of secure memory available to BL3-1
- The extents of memory available to BL3-2 (not yet implemented) and
BL3-3
- Information to execute BL3-2 (not yet implemented) and BL3-3 images
This patch also introduces a new platform API (bl2_get_bl31_args_ptr)
that needs to be implemented by the platform code to export reference to
bl31_args structure which has been allocated in platform-defined memory.
The platform will initialize the extents of memory available to BL3-3
during early platform setup in bl31_args structure. This obviates the
need for bl2_get_ns_mem_layout platform API.
BL2 calls the bl2_get_bl31_args_ptr function to get a reference to
bl31_args structure. It uses the 'bl33_meminfo' field of this structure
to load the BL3-3 image. It sets the entry point information for the
BL3-3 image in the 'bl33_image_info' field of this structure. The
reference to this structure is passed to the BL3-1 image.
Also fixes issue ARM-software/tf-issues#25
Change-Id: Ic36426196dd5ebf89e60ff42643bed01b3500517
Platform setup code has to reserve some memory for storing the
memory layout information. It is populated in early platform setup
code.
blx_get_sec_mem_layout() functions used to return a copy of this
structure. This patch modifies blx_get_sec_mem_layout() functions
so that they now directly return a pointer to their memory layout
structure. It ensures that the memory layout returned by
blx_get_sec_mem_layout() is always up-to-date and also avoids a
useless copy of the meminfo structure.
Also rename blx_get_sec_mem_layout() to blx_plat_sec_mem_layout()
to make it clear those functions are platform specific.
Change-Id: Ic7a6f9d6b6236b14865ab48a9f5eff545ce56551
- Add instructions for contributing to ARM Trusted Firmware.
- Update copyright text in all files to acknowledge contributors.
Change-Id: I9311aac81b00c6c167d2f8c889aea403b84450e5
Isla Mitchell
dp-arm
Antonio Nino Diaz
Jeenu Viswambharan
Yatharth Kochar
Soby Mathew
Juan Castillo
Sandrine Bailleux
Vikram Kanigiri
Andrew Thoelke
Dan Handley
Jon Medhurst
Achin Gupta
James Morrissey