1. 23 May, 2014 6 commits
    • Dan Handley's avatar
      Add enable mmu platform porting interfaces · dff8e47a
      Dan Handley authored
      Previously, the enable_mmu_elX() functions were implicitly part of
      the platform porting layer since they were included by generic
      code. These functions have been placed behind 2 new platform
      functions, bl31_plat_enable_mmu() and bl32_plat_enable_mmu().
      These are weakly defined so that they can be optionally overridden
      by platform ports.
      
      Also, the enable_mmu_elX() functions have been moved to
      lib/aarch64/xlat_tables.c for optional re-use by platform ports.
      These functions are tightly coupled with the translation table
      initialization code.
      
      Fixes ARM-software/tf-issues#152
      
      Change-Id: I0a2251ce76acfa3c27541f832a9efaa49135cc1c
      dff8e47a
    • Dan Handley's avatar
      Split platform.h into separate headers · 5f0cdb05
      Dan Handley authored
      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
      5f0cdb05
    • Dan Handley's avatar
      Remove unused data declarations · 7a9a5f2d
      Dan Handley authored
      Some data variables were declared but not used. These have been
      removed.
      
      Change-Id: I038632af3c32d88984cd25b886c43ff763269bf9
      7a9a5f2d
    • Dan Handley's avatar
      Remove extern keyword from function declarations · c6bc0710
      Dan Handley authored
      Function declarations implicitly have external linkage so do not
      need the extern keyword.
      
      Change-Id: Ia0549786796d8bf5956487e8996450a0b3d79f32
      c6bc0710
    • Andrew Thoelke's avatar
      Use a vector table for TSP entrypoints · 399fb08f
      Andrew Thoelke authored
      The TSP has a number of entrypoints used by the TSP on different
      occasions. These were provided to the TSPD as a table of function
      pointers, and required the TSPD to read the entry in the table,
      which is in TSP memory, in order to program the exception return
      address.
      
      Ideally, the TSPD has no access to the TSP memory.
      
      This patch changes the table of function pointers into a vector
      table of single instruction entrypoints. This allows the TSPD to
      calculate the entrypoint address instead of read it.
      
      Fixes ARM-software/tf-issues#160
      
      Change-Id: Iec6e055d537ade78a45799fbc6f43765a4725ad3
      399fb08f
    • Soby Mathew's avatar
      Non-Secure Interrupt support during Standard SMC processing in TSP · 239b04fa
      Soby Mathew authored
      Implements support for Non Secure Interrupts preempting the
      Standard SMC call in EL1. Whenever an IRQ is trapped in the
      Secure world we securely handover to the Normal world
      to process the interrupt. The normal world then issues
      "resume" smc call to resume the previous interrupted SMC call.
      Fixes ARM-software/tf-issues#105
      
      Change-Id: I72b760617dee27438754cdfc9fe9bcf4cc024858
      239b04fa
  2. 22 May, 2014 8 commits
    • Achin Gupta's avatar
      Add S-EL1 interrupt handling support in the TSPD · b44a4435
      Achin Gupta authored
      This patch adds support in the TSPD for registering a handler for
      S-EL1 interrupts. This handler ferries the interrupts generated in the
      non-secure state to the TSP at 'tsp_fiq_entry'. Support has been added
      to the smc handler to resume execution in the non-secure state once
      interrupt handling has been completed by the TSP.
      
      There is also support for resuming execution in the normal world if
      the TSP receives a EL3 interrupt. This code is currently unused.
      
      Change-Id: I816732595a2635e299572965179f11aa0bf93b69
      b44a4435
    • Achin Gupta's avatar
      Use secure timer to generate S-EL1 interrupts · fa9c08b7
      Achin Gupta authored
      This patch adds support in the TSP to program the secure physical
      generic timer to generate a EL-1 interrupt every half second. It also
      adds support for maintaining the timer state across power management
      operations. The TSPD ensures that S-EL1 can access the timer by
      programming the SCR_EL3.ST bit.
      
      This patch does not actually enable the timer. This will be done in a
      subsequent patch once the complete framework for handling S-EL1
      interrupts is in place.
      
      Change-Id: I1b3985cfb50262f60824be3a51c6314ce90571bc
      fa9c08b7
    • Achin Gupta's avatar
      Introduce interrupt handling framework in BL3-1 · dce74b89
      Achin Gupta authored
      This patch adds a common handler for FIQ and IRQ exceptions in the
      BL3-1 runtime exception vector table. This function determines the
      interrupt type and calls its handler. A crash is reported if an
      inconsistency in the interrupt management framework is detected. In
      the event of a spurious interrupt, execution resumes from the
      instruction where the interrupt was generated.
      
      This patch also removes 'cm_macros.S' as its contents have been moved
      to 'runtime_exceptions.S'
      
      Change-Id: I3c85ecf8eaf43a3fac429b119ed0bd706d2e2093
      dce74b89
    • Achin Gupta's avatar
      Add context library API to change a bit in SCR_EL3 · c429b5e9
      Achin Gupta authored
      This patch adds an API to write to any bit in the SCR_EL3 member of
      the 'cpu_context' structure of the current CPU for a specified
      security state. This API will be used in subsequent patches which
      introduce interrupt management in EL3 to specify the interrupt routing
      model when execution is not in EL3.
      
      It also renames the cm_set_el3_elr() function to cm_set_elr_el3()
      which is more in line with the system register name being targeted by
      the API.
      
      Change-Id: I310fa7d8f827ad3f350325eca2fb28cb350a85ed
      c429b5e9
    • Achin Gupta's avatar
      Rework 'state' field usage in per-cpu TSP context · 3ee8a164
      Achin Gupta authored
      This patch lays the foundation for using the per-cpu 'state' field in
      the 'tsp_context' structure for other flags apart from the power state
      of the TSP.
      
      It allocates 2 bits for the power state, introduces the necessary
      macros to manipulate the power state in the 'state' field and
      accordingly reworks all use of the TSP_STATE_* states.
      
      It also allocates a flag bit to determine if the TSP is handling a
      standard SMC. If this flag is set then the TSP was interrupted due to
      non-secure or EL3 interupt depending upon the chosen routing
      model. Macros to get, set and clear this flag have been added as
      well. This flag will be used by subsequent patches.
      
      Change-Id: Ic6ee80bd5895812c83b35189cf2c3be70a9024a6
      3ee8a164
    • Vikram Kanigiri's avatar
      Rework memory information passing to BL3-x images · 6871c5d3
      Vikram Kanigiri authored
      The issues addressed in this patch are:
      
      1. Remove meminfo_t from the common interfaces in BL3-x,
      expecting that platform code will find a suitable mechanism
      to determine the memory extents in these images and provide
      it to the BL3-x images.
      
      2. Remove meminfo_t and bl31_plat_params_t from all FVP BL3-x
      code as the images use link-time information to determine
      memory extents.
      
      meminfo_t is still used by common interface in BL1/BL2 for
      loading images
      
      Change-Id: I4e825ebf6f515b59d84dc2bdddf6edbf15e2d60f
      6871c5d3
    • Vikram Kanigiri's avatar
      Populate BL31 input parameters as per new spec · 4112bfa0
      Vikram Kanigiri authored
      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
      4112bfa0
    • Vikram Kanigiri's avatar
      Introduce macros to manipulate the SPSR · 23ff9baa
      Vikram Kanigiri authored
      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
      23ff9baa
  3. 16 May, 2014 1 commit
    • Soby Mathew's avatar
      Rework BL3-1 unhandled exception handling and reporting · a43d431b
      Soby Mathew authored
      This patch implements the register reporting when unhandled exceptions are
      taken in BL3-1. Unhandled exceptions will result in a dump of registers
      to the console, before halting execution by that CPU. The Crash Stack,
      previously called the Exception Stack, is used for this activity.
      This stack is used to preserve the CPU context and runtime stack
      contents for debugging and analysis.
      
      This also introduces the per_cpu_ptr_cache, referenced by tpidr_el3,
      to provide easy access to some of BL3-1 per-cpu data structures.
      Initially, this is used to provide a pointer to the Crash stack.
      
      panic() now prints the the error file and line number in Debug mode
      and prints the PC value in release mode.
      
      The Exception Stack is renamed to Crash Stack with this patch.
      The original intention of exception stack is no longer valid
      since we intend to support several valid exceptions like IRQ
      and FIQ in the trusted firmware context. This stack is now
      utilized for dumping and reporting the system state when a
      crash happens and hence the rename.
      
      Fixes ARM-software/tf-issues#79 Improve reporting of unhandled exception
      
      Change-Id: I260791dc05536b78547412d147193cdccae7811a
      a43d431b
  4. 12 May, 2014 1 commit
    • Achin Gupta's avatar
      Fix broken standby state implementation in PSCI · 317ba090
      Achin Gupta authored
      This patch fixes the broken support for entry into standby states
      introduced under commit-id 'd118f9f8' (tf-issues#94). Upon exit from
      the platform defined standby state instead of returning to the caller
      of the SMC, execution would get stuck in the wfi instruction meant for
      entering a power down state. This patch ensures that exit from a
      standby state and entry into a power down state do not interfere with
      each other.
      
      Fixes ARM-software/tf-issues#154
      
      Change-Id: I56e5df353368e44d6eefc94ffedefe21929f5cfe
      317ba090
  5. 09 May, 2014 1 commit
    • Sandrine Bailleux's avatar
      fvp: Provide per-EL MMU setup functions · b793e431
      Sandrine Bailleux authored
      Instead of having a single version of the MMU setup functions for all
      bootloader images that can execute either in EL3 or in EL1, provide
      separate functions for EL1 and EL3. Each bootloader image can then
      call the appropriate version of these functions. The aim is to reduce
      the amount of code compiled in each BL image by embedding only what's
      needed (e.g. BL1 to embed only EL3 variants).
      
      Change-Id: Ib86831d5450cf778ae78c9c1f7553fe91274c2fa
      b793e431
  6. 08 May, 2014 1 commit
    • Soby Mathew's avatar
      Preserve x19-x29 across world switch for exception handling · c3260f9b
      Soby Mathew authored
      Previously exception handlers in BL3-1, X19-X29 were not saved
      and restored on every SMC/trap into EL3. Instead these registers
      were 'saved as needed' as a side effect of the A64 ABI used by the C
      compiler.
      
      That approach failed when world switching but was not visible
      with the TSP/TSPD code because the TSP is 64-bit, did not
      clobber these registers when running and did not support pre-emption
      by normal world interrupts. These scenarios showed
      that the values in these registers can be passed through a world
      switch, which broke the normal and trusted world assumptions
      about these registers being preserved.
      
      The Ideal solution saves and restores these registers when a
      world switch occurs - but that type of implementation is more complex.
      So this patch always saves and restores these registers on entry and
      exit of EL3.
      
      Fixes ARM-software/tf-issues#141
      
      Change-Id: I9a727167bbc594454e81cf78a97ca899dfb11c27
      c3260f9b
  7. 07 May, 2014 2 commits
    • Andrew Thoelke's avatar
      Access system registers directly in assembler · 7935d0a5
      Andrew Thoelke authored
      Instead of using the system register helper functions to read
      or write system registers, assembler coded functions should
      use MRS/MSR instructions. This results in faster and more
      compact code.
      
      This change replaces all usage of the helper functions with
      direct register accesses.
      
      Change-Id: I791d5f11f257010bb3e6a72c6c5ab8779f1982b3
      7935d0a5
    • Andrew Thoelke's avatar
      Correct usage of data and instruction barriers · 8cec598b
      Andrew Thoelke authored
      The current code does not always use data and instruction
      barriers as required by the architecture and frequently uses
      barriers excessively due to their inclusion in all of the
      write_*() helper functions.
      
      Barriers should be used explicitly in assembler or C code
      when modifying processor state that requires the barriers in
      order to enable review of correctness of the code.
      
      This patch removes the barriers from the helper functions and
      introduces them as necessary elsewhere in the code.
      
      PORTING NOTE: check any port of Trusted Firmware for use of
      system register helper functions for reliance on the previous
      barrier behaviour and add explicit barriers as necessary.
      
      Fixes ARM-software/tf-issues#92
      
      Change-Id: Ie63e187404ff10e0bdcb39292dd9066cb84c53bf
      8cec598b
  8. 06 May, 2014 9 commits
    • Dan Handley's avatar
      Remove variables from .data section · 625de1d4
      Dan Handley authored
      Update code base to remove variables from the .data section,
      mainly by using const static data where possible and adding
      the const specifier as required. Most changes are to the IO
      subsystem, including the framework APIs. The FVP power
      management code is also affected.
      
      Delay initialization of the global static variable,
      next_image_type in bl31_main.c, until it is realy needed.
      Doing this moves the variable from the .data to the .bss
      section.
      
      Also review the IO interface for inconsistencies, using
      uintptr_t where possible instead of void *. Remove the
      io_handle and io_dev_handle typedefs, which were
      unnecessary, replacing instances with uintptr_t.
      
      Fixes ARM-software/tf-issues#107.
      
      Change-Id: I085a62197c82410b566e4698e5590063563ed304
      625de1d4
    • Dan Handley's avatar
      Reduce deep nesting of header files · 97043ac9
      Dan Handley authored
      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.
      
      Fixes ARM-software/tf-issues#31
      
      Change-Id: Iec92fb976334c77453e010b60bcf56f3be72bd3e
      97043ac9
    • Dan Handley's avatar
      Always use named structs in header files · fb037bfb
      Dan Handley authored
      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
      fb037bfb
    • Dan Handley's avatar
      Move PSCI global functions out of private header · c5945735
      Dan Handley authored
      Move the PSCI global functions out of psci_private.h and into
      psci.h to allow the standard service to only depend on psci.h.
      
      Change-Id: I8306924a3814b46e70c1dcc12524c7aefe06eed1
      c5945735
    • Dan Handley's avatar
      Separate BL functions out of arch.h · 5b827a8f
      Dan Handley authored
      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
      5b827a8f
    • Dan Handley's avatar
      Separate out CASSERT macro into own header · bdbfc3c2
      Dan Handley authored
      Separate out the CASSERT macro out of bl_common.h into its own
      header to allow more efficient header inclusion.
      
      Change-Id: I291be0b6b8f9879645e839a8f0dd1ec9b3db9639
      bdbfc3c2
    • Dan Handley's avatar
      Remove vpath usage in makefiles · bee82417
      Dan Handley authored
      Remove all usage of the vpath keyword in makefiles as it was prone
      to mistakes. Specify the relative paths to source files instead.
      
      Also reorder source files in makefiles alphabetically.
      
      Fixes ARM-software/tf-issues#121
      
      Change-Id: Id15f60655444bae60e0e2165259efac71a50928b
      bee82417
    • Dan Handley's avatar
      Make use of user/system includes more consistent · 35e98e55
      Dan Handley authored
      Make codebase consistent in its use of #include "" syntax for
      user includes and #include <> syntax for system includes.
      
      Fixes ARM-software/tf-issues#65
      
      Change-Id: If2f7c4885173b1fd05ac2cde5f1c8a07000c7a33
      35e98e55
    • Dan Handley's avatar
      Move include and source files to logical locations · 4ecca339
      Dan Handley authored
      Move almost all system include files to a logical sub-directory
      under ./include. The only remaining system include directories
      not under ./include are specific to the platform. Move the
      corresponding source files to match the include directory
      structure.
      
      Also remove pm.h as it is no longer used.
      
      Change-Id: Ie5ea6368ec5fad459f3e8a802ad129135527f0b3
      4ecca339
  9. 29 Apr, 2014 1 commit
    • Vikram Kanigiri's avatar
      Preserve PSCI cpu_suspend 'power_state' parameter. · 759ec93b
      Vikram Kanigiri authored
      This patch saves the 'power_state' parameter prior to suspending
      a cpu and invalidates it upon its resumption. The 'affinity level'
      and 'state id' fields of this parameter can be read using a set of
      public and private apis. Validation of power state parameter is
      introduced which checks for SBZ bits are zero.
      This change also takes care of flushing the parameter from the cache
      to main memory. This ensures that it is available after cpu reset
      when the caches and mmu are turned off. The earlier support for
      saving only the 'affinity level' field of the 'power_state' parameter
      has also been reworked.
      
      Fixes ARM-Software/tf-issues#26
      Fixes ARM-Software/tf-issues#130
      
      Change-Id: Ic007ccb5e39bf01e0b67390565d3b4be33f5960a
      759ec93b
  10. 26 Mar, 2014 4 commits
    • Andrew Thoelke's avatar
      Place assembler functions in separate sections · 0a30cf54
      Andrew Thoelke authored
      This extends the --gc-sections behaviour to the many assembler
      support functions in the firmware images by placing each function
      into its own code section. This is achieved by creating a 'func'
      macro used to declare each function label.
      
      Fixes ARM-software/tf-issues#80
      
      Change-Id: I301937b630add292d2dec6d2561a7fcfa6fec690
      0a30cf54
    • Achin Gupta's avatar
      Fix build failure due to a typo in TSPD code · 2eb01d34
      Achin Gupta authored
      This patch fixes a build failure when TSPD support is included. The failure was
      due to a missing semi-colon at the end of a C statement in tspd_common.c
      
      Change-Id: I8fbd0d500bd9145b15f862b8686e570b80fcce8c
      2eb01d34
    • Vikram Kanigiri's avatar
      Fix build by correcting asm helper function usage in TSPD · 31526cb0
      Vikram Kanigiri authored
      This patch fixes a regression failure due to the use of functions by the 
      TSPD code which access system registers with partially qualified names. 
      These functions had been removed in an earlier patch. The relevant code 
      has been updated to access these registers with their fully qualified 
      names.
      
      Fixes ARM-software/tf-issues#119
      
      Change-Id: Ide1bc5036e1b8164a42f7b7fe86186ad860e0ef9
      31526cb0
    • Vikram Kanigiri's avatar
      Add standby state support in PSCI cpu_suspend api · d118f9f8
      Vikram Kanigiri authored
      This patch adds support in the generic PSCI implementation to call a
      platform specific function to enter a standby state using an example
      implementation in ARM FVP port
      
      Fixes ARM-software/tf-issues#94
      Change-Id: Ic1263fcf25f28e09162ad29dca954125f9aa8cc9
      d118f9f8
  11. 21 Mar, 2014 1 commit
    • Vikram Kanigiri's avatar
      Remove partially qualified asm helper functions · 6ba0b6d6
      Vikram Kanigiri authored
      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
      6ba0b6d6
  12. 20 Mar, 2014 2 commits
    • Jeenu Viswambharan's avatar
      Implement standard calls for TSP · 52538b9b
      Jeenu Viswambharan authored
      This patch adds call count, UID and version information SMC calls for
      the Trusted OS, as specified by the SMC calling convention.
      
      Change-Id: I9a3e84ac1bb046051db975d853dcbe9612aba6a9
      52538b9b
    • Jeenu Viswambharan's avatar
      Implement ARM Standard Service · 64f6ea9b
      Jeenu Viswambharan authored
      This patch implements ARM Standard Service as a runtime service and adds
      support for call count, UID and revision information SMCs. The existing
      PSCI implementation is subsumed by the Standard Service calls and all
      PSCI calls are therefore dispatched by the Standard Service to the PSCI
      handler.
      
      At present, PSCI is the only specification under Standard Service. Thus
      call count returns the number of PSCI calls implemented. As this is the
      initial implementation, a revision number of 0.1 is returned for call
      revision.
      
      Fixes ARM-software/tf-issues#62
      
      Change-Id: I6d4273f72ad6502636efa0f872e288b191a64bc1
      64f6ea9b
  13. 05 Mar, 2014 1 commit
    • Jon Medhurst's avatar
      Update Makefiles to get proper dependency checking working. · 6d55d109
      Jon Medhurst authored
      
      
      This change requires all platforms to now specify a list of source files
      rather than object files.
      
      New source files should preferably be specified by using the path as
      well and we should add this in the future for all files so we can remove
      use of vpath. This is desirable because vpath hides issues like the fact
      that BL2 currently pulls in a BL1 file bl1/aarch64/early_exceptions.S
      and if in the future we added bl2/aarch64/early_exceptions.S then it's
      likely only one of the two version would be used for both bootloaders.
      
      This change also removes the 'dump' build target and simply gets
      bootloaders to always generate a dump file. At the same time the -x
      option is added so the section headers and symbols table are listed.
      
      Fixes ARM-software/tf-issues#11
      
      Change-Id: Ie38f7be76fed95756c8576cf3f3ea3b7015a18dc
      Signed-off-by: default avatarJon Medhurst <tixy@linaro.org>
      6d55d109
  14. 26 Feb, 2014 1 commit
    • Jeenu Viswambharan's avatar
      Implement late binding for runtime hooks · 7f366605
      Jeenu Viswambharan authored
      At present SPD power management hooks and BL3-2 entry are implemented
      using weak references. This would have the handlers bound and registered
      with the core framework at build time, but leaves them dangling if a
      service fails to initialize at runtime.
      
      This patch replaces implementation by requiring runtime handlers to
      register power management and deferred initialization hooks with the
      core framework at runtime. The runtime services are to register the
      hooks only as the last step, after having all states successfully
      initialized.
      
      Change-Id: Ibe788a2a381ef39aec1d4af5ba02376e67269782
      7f366605
  15. 20 Feb, 2014 1 commit
    • Achin Gupta's avatar
      Rework arithmetic operations in Test Secure Payload · 916a2c1e
      Achin Gupta authored
      
      
      This patch reworks the service provided by the TSP to perform common
      arithmetic operations on a set of arguments provided by the non-secure
      world. For a addition, division, subtraction & multiplication operation
      requested on two arguments in x0 and x1 the steps are:
      
      1. TSPD saves the non-secure context and passes the operation and its
         arguments to the TSP.
      
      2. TSP asks the TSPD to return the same arguments once again. This
         exercises an additional SMC path.
      
      3. TSP now has two copies of both x0 and x1. It performs the operation
         on the corresponding copies i.e. in case of addition it returns x0+x0
         and x1+x1.
      
      4. TSPD receives the result, saves the secure context, restores the
         non-secure context and passes the result back to the non-secure
         client.
      
      Change-Id: I6eebfa2ae0a6f28b1d2e11a31f575c7a4b96724b
      Co-authored-by: default avatarJeenu Viswambharan <jeenu.viswambharan@arm.com>
      916a2c1e