1. 06 Mar, 2017 4 commits
  2. 23 Feb, 2017 2 commits
  3. 06 Feb, 2017 1 commit
    • Douglas Raillard's avatar
      Replace some memset call by zeromem · 32f0d3c6
      Douglas Raillard authored
      
      
      Replace all use of memset by zeromem when zeroing moderately-sized
      structure by applying the following transformation:
      memset(x, 0, sizeof(x)) => zeromem(x, sizeof(x))
      
      As the Trusted Firmware is compiled with -ffreestanding, it forbids the
      compiler from using __builtin_memset and forces it to generate calls to
      the slow memset implementation. Zeromem is a near drop in replacement
      for this use case, with a more efficient implementation on both AArch32
      and AArch64.
      
      Change-Id: Ia7f3a90e888b96d056881be09f0b4d65b41aa79e
      Signed-off-by: default avatarDouglas Raillard <douglas.raillard@arm.com>
      32f0d3c6
  4. 26 Jan, 2017 1 commit
    • David Cunado's avatar
      Resolve build errors flagged by GCC 6.2 · 9edac047
      David Cunado authored
      
      
      With GCC 6.2 compiler, more C undefined behaviour is being flagged as
      warnings, which result in build errors in ARM TF build.
      
      The specific issue that this patch resolves is the use of (1 << 31),
      which is predominantly used in case statements, where 1 is represented
      as a signed int. When shifted to msb the behaviour is undefined.
      
      The resolution is to specify 1 as an unsigned int using a convenience
      macro ULL(). A duplicate macro MAKE_ULL() is replaced.
      
      Fixes ARM-software/tf-issues#438
      
      Change-Id: I08e3053bbcf4c022ee2be33a75bd0056da4073e1
      Signed-off-by: default avatarDavid Cunado <david.cunado@arm.com>
      9edac047
  5. 23 Dec, 2016 1 commit
    • Douglas Raillard's avatar
      Abort preempted TSP STD SMC after PSCI CPU suspend · 3df6012a
      Douglas Raillard authored
      
      
      Standard SMC requests that are handled in the secure-world by the Secure
      Payload can be preempted by interrupts that must be handled in the
      normal world. When the TSP is preempted the secure context is stored and
      control is passed to the normal world to handle the non-secure
      interrupt. Once completed the preempted secure context is restored. When
      restoring the preempted context, the dispatcher assumes that the TSP
      preempted context is still stored as the SECURE context by the context
      management library.
      
      However, PSCI power management operations causes synchronous entry into
      TSP. This overwrites the preempted SECURE context in the context
      management library. When restoring back the SECURE context, the Secure
      Payload crashes because this context is not the preempted context
      anymore.
      
      This patch avoids corruption of the preempted SECURE context by aborting
      any preempted SMC during PSCI power management calls. The
      abort_std_smc_entry hook of the TSP is called when aborting the SMC
      request.
      
      It also exposes this feature as a FAST SMC callable from normal world to
      abort preempted SMC with FID TSP_FID_ABORT.
      
      Change-Id: I7a70347e9293f47d87b5de20484b4ffefb56b770
      Signed-off-by: default avatarDouglas Raillard <douglas.raillard@arm.com>
      3df6012a
  6. 30 Nov, 2016 1 commit
  7. 23 Nov, 2016 2 commits
    • Sandrine Bailleux's avatar
      Fix a coding style issue in trusty.c · 48c1c39f
      Sandrine Bailleux authored
      
      
      This patch fixes the following coding style error reported
      by the checkpatch.pl script:
      
        Bad function definition - void el3_exit() should probably
        be void el3_exit(void)
      
      There is another one but it's a false positive so there's no
      point in fixing it:
      
        space prohibited after that '&' (ctx:WxW)
        +#define SMC_NR(entity, fn, fastcall, smc64) ((((fastcall) & 0x1) << 31) | \
                                                                  ^
      Change-Id: I34de0337c7216dabd16395879f13845a60ee6df0
      Signed-off-by: default avatarSandrine Bailleux <sandrine.bailleux@arm.com>
      48c1c39f
    • Sandrine Bailleux's avatar
      Fix compilation warning in Trusty SPD · 696f41ec
      Sandrine Bailleux authored
      
      
      In release builds, the Trusty SPD fails to build because of an unused
      variable. Note that this warning message doesn't show in debug builds
      because INFO() messages are not compiled out like in release mode.
      
      This patch fixes this issue by removing this variable and using its
      value in place directly in the INFO() macro call.
      
      Change-Id: I1f552421181a09412315eef4eaca586012022018
      Signed-off-by: default avatarSandrine Bailleux <sandrine.bailleux@arm.com>
      696f41ec
  8. 08 Nov, 2016 1 commit
  9. 03 Nov, 2016 1 commit
    • dp-arm's avatar
      Perform a cache flush after ENTER PSCI timestamp capture · bfef6106
      dp-arm authored
      
      
      Without an explicit cache flush, the next timestamp captured might have
      a bogus value.
      
      This can happen if the following operations happen in order,
      on a CPU that's being powered down.
      
      1) ENTER PSCI timestamp is captured with caches enabled.
      
      2) The next timestamp (ENTER_HW_LOW_PWR) is captured with caches
         disabled.
      
      3) On a system that uses a write-back cache configuration, the
         cache line that holds the PMF timestamps is evicted.
      
      After step 1), the ENTER_PSCI timestamp is cached and not in main memory.
      After step 2), the ENTER_HW_LOW_PWR timestamp is stored in main memory.
      Before the CPU power down happens, the hardware evicts the cache line that
      contains the PMF timestamps for this service.  As a result, the timestamp
      captured in step 2) is overwritten with a bogus value.
      
      Change-Id: Ic1bd816498d1a6d4dc16540208ed3a5efe43f529
      Signed-off-by: default avatardp-arm <dimitris.papastamos@arm.com>
      bfef6106
  10. 12 Oct, 2016 1 commit
    • dp-arm's avatar
      Add PMF instrumentation points in TF · 872be88a
      dp-arm authored
      
      
      In order to quantify the overall time spent in the PSCI software
      implementation, an initial collection of PMF instrumentation points
      has been added.
      
      Instrumentation has been added to the following code paths:
      
      - Entry to PSCI SMC handler.  The timestamp is captured as early
        as possible during the runtime exception and stored in memory
        before entering the PSCI SMC handler.
      
      - Exit from PSCI SMC handler.  The timestamp is captured after
        normal return from the PSCI SMC handler or if a low power state
        was requested it is captured in the bl31 warm boot path before
        return to normal world.
      
      - Entry to low power state.  The timestamp is captured before entry
        to a low power state which implies either standby or power down.
        As these power states are mutually exclusive, only one timestamp
        is defined to describe both.  It is possible to differentiate between
        the two power states using the PSCI STAT interface.
      
      - Exit from low power state.  The timestamp is captured after a standby
        or power up operation has completed.
      
      To calculate the number of cycles spent running code in Trusted Firmware
      one can perform the following calculation:
      
      (exit_psci - enter_psci) - (exit_low_pwr - enter_low_pwr).
      
      The resulting number of cycles can be converted to time given the
      frequency of the counter.
      
      Change-Id: Ie3b8f3d16409b6703747093b3a2d5c7429ad0166
      Signed-off-by: default avatardp-arm <dimitris.papastamos@arm.com>
      872be88a
  11. 22 Sep, 2016 1 commit
    • Soby Mathew's avatar
      PSCI: Do psci_setup() as part of std_svc_setup() · 58e946ae
      Soby Mathew authored
      This patch moves the invocation of `psci_setup()` from BL31 and SP_MIN
      into `std_svc_setup()` as part of ARM Standard Service initialization.
      This allows us to consolidate ARM Standard Service initializations which
      will be added to in the future. A new function `get_arm_std_svc_args()`
      is introduced to get arguments corresponding to each standard service.
      This function must be implemented by the EL3 Runtime Firmware and both
      SP_MIN and BL31 implement it.
      
      Change-Id: I38e1b644f797fa4089b20574bd4a10f0419de184
      58e946ae
  12. 19 Jul, 2016 1 commit
    • Soby Mathew's avatar
      Introduce PSCI Library Interface · cf0b1492
      Soby Mathew authored
      This patch introduces the PSCI Library interface. The major changes
      introduced are as follows:
      
      * Earlier BL31 was responsible for Architectural initialization during cold
      boot via bl31_arch_setup() whereas PSCI was responsible for the same during
      warm boot. This functionality is now consolidated by the PSCI library
      and it does Architectural initialization via psci_arch_setup() during both
      cold and warm boots.
      
      * Earlier the warm boot entry point was always `psci_entrypoint()`. This was
      not flexible enough as a library interface. Now PSCI expects the runtime
      firmware to provide the entry point via `psci_setup()`. A new function
      `bl31_warm_entrypoint` is introduced in BL31 and the previous
      `psci_entrypoint()` is deprecated.
      
      * The `smc_helpers.h` is reorganized to separate the SMC Calling Convention
      defines from the Trusted Firmware SMC helpers. The former is now in a new
      header file `smcc.h` and the SMC helpers are moved to Architecture specific
      header.
      
      * The CPU context is used by PSCI for context initialization and
      restoration after power down (PSCI Context). It is also used by BL31 for SMC
      handling and context management during Normal-Secure world switch (SMC
      Context). The `psci_smc_handler()` interface is redefined to not use SMC
      helper macros thus enabling to decouple the PSCI context from EL3 runtime
      firmware SMC context. This enables PSCI to be integrated with other runtime
      firmware using a different SMC context.
      
      NOTE: With this patch the architectural setup done in `bl31_arch_setup()`
      is done as part of `psci_setup()` and hence `bl31_platform_setup()` will be
      invoked prior to architectural setup. It is highly unlikely that the platform
      setup will depend on architectural setup and cause any failure. Please be
      be aware of this change in sequence.
      
      Change-Id: I7f497a08d33be234bbb822c28146250cb20dab73
      cf0b1492
  13. 18 Jul, 2016 3 commits
    • Soby Mathew's avatar
      Introduce `el3_runtime` and `PSCI` libraries · 532ed618
      Soby Mathew authored
      This patch moves the PSCI services and BL31 frameworks like context
      management and per-cpu data into new library components `PSCI` and
      `el3_runtime` respectively. This enables PSCI to be built independently from
      BL31. A new `psci_lib.mk` makefile is introduced which adds the relevant
      PSCI library sources and gets included by `bl31.mk`. Other changes which
      are done as part of this patch are:
      
      * The runtime services framework is now moved to the `common/` folder to
        enable reuse.
      * The `asm_macros.S` and `assert_macros.S` helpers are moved to architecture
        specific folder.
      * The `plat_psci_common.c` is moved from the `plat/common/aarch64/` folder
        to `plat/common` folder. The original file location now has a stub which
        just includes the file from new location to maintain platform compatibility.
      
      Most of the changes wouldn't affect platform builds as they just involve
      changes to the generic bl1.mk and bl31.mk makefiles.
      
      NOTE: THE `plat_psci_common.c` FILE HAS MOVED LOCATION AND THE STUB FILE AT
      THE ORIGINAL LOCATION IS NOW DEPRECATED. PLATFORMS SHOULD MODIFY THEIR
      MAKEFILES TO INCLUDE THE FILE FROM THE NEW LOCATION.
      
      Change-Id: I6bd87d5b59424995c6a65ef8076d4fda91ad5e86
      532ed618
    • Soby Mathew's avatar
      Fix coding guideline warnings · da554d74
      Soby Mathew authored
      This patch fixes some coding guideline warnings reported by the checkpatch
      script. Only files related to upcoming feature development have been fixed.
      
      Change-Id: I26fbce75c02ed62f00493ed6c106fe7c863ddbc5
      da554d74
    • Soby Mathew's avatar
      Rework type usage in Trusted Firmware · 4c0d0390
      Soby Mathew authored
      This patch reworks type usage in generic code, drivers and ARM platform files
      to make it more portable. The major changes done with respect to
      type usage are as listed below:
      
      * Use uintptr_t for storing address instead of uint64_t or unsigned long.
      * Review usage of unsigned long as it can no longer be assumed to be 64 bit.
      * Use u_register_t for register values whose width varies depending on
        whether AArch64 or AArch32.
      * Use generic C types where-ever possible.
      
      In addition to the above changes, this patch also modifies format specifiers
      in print invocations so that they are AArch64/AArch32 agnostic. Only files
      related to upcoming feature development have been reworked.
      
      Change-Id: I9f8c78347c5a52ba7027ff389791f1dad63ee5f8
      4c0d0390
  14. 16 Jun, 2016 1 commit
    • Yatharth Kochar's avatar
      Add optional PSCI STAT residency & count functions · 170fb93d
      Yatharth Kochar authored
      This patch adds following optional PSCI STAT functions:
      
      - PSCI_STAT_RESIDENCY: This call returns the amount of time spent
        in power_state in microseconds, by the node represented by the
        `target_cpu` and the highest level of `power_state`.
      
      - PSCI_STAT_COUNT: This call returns the number of times a
        `power_state` has been used by the node represented by the
        `target_cpu` and the highest power level of `power_state`.
      
      These APIs provides residency statistics for power states that has
      been used by the platform. They are implemented according to v1.0
      of the PSCI specification.
      
      By default this optional feature is disabled in the PSCI
      implementation. To enable it, set the boolean flag
      `ENABLE_PSCI_STAT` to 1. This also sets `ENABLE_PMF` to 1.
      
      Change-Id: Ie62e9d37d6d416ccb1813acd7f616d1ddd3e8aff
      170fb93d
  15. 13 Jun, 2016 1 commit
  16. 25 May, 2016 1 commit
    • Soby Mathew's avatar
      PSCI: Add pwr_domain_pwr_down_wfi() hook in plat_psci_ops · ac1cc8eb
      Soby Mathew authored
      This patch adds a new optional platform hook `pwr_domain_pwr_down_wfi()` in
      the plat_psci_ops structure. This hook allows the platform to perform platform
      specific actions including the wfi invocation to enter powerdown. This hook
      is invoked by both psci_do_cpu_off() and psci_cpu_suspend_start() functions.
      The porting-guide.md is also updated for the same.
      
      This patch also modifies the `psci_power_down_wfi()` function to invoke
      `plat_panic_handler` incase of panic instead of the busy while loop.
      
      Fixes ARM-Software/tf-issues#375
      
      Change-Id: Iba104469a1445ee8d59fb3a6fdd0a98e7f24dfa3
      ac1cc8eb
  17. 20 May, 2016 1 commit
    • Antonio Nino Diaz's avatar
      Add 32 bit version of plat_get_syscnt_freq · d4486391
      Antonio Nino Diaz authored
      Added plat_get_syscnt_freq2, which is a 32 bit variant of the 64 bit
      plat_get_syscnt_freq. The old one has been flagged as deprecated.
      Common code has been updated to use this new version. Porting guide
      has been updated.
      
      Change-Id: I9e913544926c418970972bfe7d81ee88b4da837e
      d4486391
  18. 25 Apr, 2016 2 commits
  19. 01 Apr, 2016 1 commit
  20. 08 Feb, 2016 1 commit
    • Soby Mathew's avatar
      PSCI: Resolve GCC static analysis false positive · 6d18969f
      Soby Mathew authored
      When BL31 is compiled at `-O3` optimization level using Linaro GCC 4.9
      AArch64 toolchain, it reports the following error:
      
      ```
      services/std_svc/psci/psci_common.c: In function 'psci_do_state_coordination':
      services/std_svc/psci/psci_common.c:220:27: error: array subscript is above
      array bounds [-Werror=array-bounds]
        psci_req_local_pwr_states[pwrlvl - 1][cpu_idx] = req_pwr_state;
                                 ^
      ```
      
      This error is a false positive and this patch resolves the error by asserting
      the array bounds in `psci_do_state_coordination()`.
      
      Fixes ARM-software/tf-issues#347
      
      Change-Id: I3584ed7b2e28faf455b082cb3281d6e1d11d6495
      6d18969f
  21. 01 Feb, 2016 1 commit
    • Soby Mathew's avatar
      Fix PSCI CPU ON race when setting state to ON_PENDING · 203cdfe2
      Soby Mathew authored
      When a CPU is powered down using PSCI CPU OFF API, it disables its caches
      and updates its `aff_info_state` to OFF. The corresponding cache line is
      invalidated by the CPU so that the update will be observed by other CPUs
      running with caches enabled. There is a possibility that another CPU
      which has been trying to turn ON this CPU via PSCI CPU ON API,
      has already seen the update to `aff_info_state` and proceeds to update
      the state to ON_PENDING prior to the cache invalidation. This may result
      in the update of the state to ON_PENDING being discarded.
      
      This patch fixes this issue by making sure that the update of `aff_info_state`
      to ON_PENDING sticks by reading back the value after the cache flush and
      retrying it if not updated. The patch also adds a dsbish() to
      `psci_do_cpu_off()` to ensure ordering of the update to `aff_info_state`
      prior to cache line invalidation.
      
      Fixes ARM-software/tf-issues#349
      
      Change-Id: I225de99957fe89871f8c57bcfc243956e805dcca
      203cdfe2
  22. 14 Jan, 2016 1 commit
  23. 21 Dec, 2015 1 commit
  24. 14 Dec, 2015 1 commit
  25. 09 Dec, 2015 1 commit
    • Soby Mathew's avatar
      TSP: Allow preemption of synchronous S-EL1 interrupt handling · 63b8440f
      Soby Mathew authored
      Earlier the TSP only ever expected to be preempted during Standard SMC
      processing. If a S-EL1 interrupt triggered while in the normal world, it
      will routed to S-EL1 `synchronously` for handling. The `synchronous` S-EL1
      interrupt handler `tsp_sel1_intr_entry` used to panic if this S-EL1 interrupt
      was preempted by another higher priority pending interrupt which should be
      handled in EL3 e.g. Group0 interrupt in GICv3.
      
      With this patch, the `tsp_sel1_intr_entry` now expects `TSP_PREEMPTED` as the
      return code from the `tsp_common_int_handler` in addition to 0 (interrupt
      successfully handled) and in both cases it issues an SMC with id
      `TSP_HANDLED_S_EL1_INTR`. The TSPD switches the context and returns back
      to normal world. In case a higher priority EL3 interrupt was pending, the
      execution will be routed to EL3 where interrupt will be handled. On return
      back to normal world, the pending S-EL1 interrupt which was preempted will
      get routed to S-EL1 to be handled `synchronously` via `tsp_sel1_intr_entry`.
      
      Change-Id: I2087c7fedb37746fbd9200cdda9b6dba93e16201
      63b8440f
  26. 04 Dec, 2015 2 commits
    • Soby Mathew's avatar
      Enable use of FIQs and IRQs as TSP interrupts · 02446137
      Soby Mathew authored
      On a GICv2 system, interrupts that should be handled in the secure world are
      typically signalled as FIQs. On a GICv3 system, these interrupts are signalled
      as IRQs instead. The mechanism for handling both types of interrupts is the same
      in both cases. This patch enables the TSP to run on a GICv3 system by:
      
      1. adding support for handling IRQs in the exception handling code.
      2. removing use of "fiq" in the names of data structures, macros and functions.
      
      The build option TSPD_ROUTE_IRQ_TO_EL3 is deprecated and is replaced with a
      new build flag TSP_NS_INTR_ASYNC_PREEMPT. For compatibility reasons, if the
      former build flag is defined, it will be used to define the value for the
      new build flag. The documentation is also updated accordingly.
      
      Change-Id: I1807d371f41c3656322dd259340a57649833065e
      02446137
    • Soby Mathew's avatar
      Unify interrupt return paths from TSP into the TSPD · 404dba53
      Soby Mathew authored
      The TSP is expected to pass control back to EL3 if it gets preempted due to
      an interrupt while handling a Standard SMC in the following scenarios:
      
      1. An FIQ preempts Standard SMC execution and that FIQ is not a TSP Secure
         timer interrupt or is preempted by a higher priority interrupt by the time
         the TSP acknowledges it. In this case, the TSP issues an SMC with the ID
         as `TSP_EL3_FIQ`. Currently this case is never expected to happen as only
         the TSP Secure Timer is expected to generate FIQ.
      
      2. An IRQ preempts Standard SMC execution and in this case the TSP issues
         an SMC with the ID as `TSP_PREEMPTED`.
      
      In both the cases, the TSPD hands control back to the normal world and returns
      returns an error code to the normal world to indicate that the standard SMC it
      had issued has been preempted but not completed.
      
      This patch unifies the handling of these two cases in the TSPD and ensures that
      the TSP only uses TSP_PREEMPTED instead of separate SMC IDs. Also instead of 2
      separate error codes, SMC_PREEMPTED and TSP_EL3_FIQ, only SMC_PREEMPTED is
      returned as error code back to the normal world.
      
      Background information: On a GICv3 system, when the secure world has affinity
      routing enabled, in 2. an FIQ will preempt TSP execution instead of an IRQ. The
      FIQ could be a result of a Group 0 or a Group 1 NS interrupt. In both case, the
      TSPD passes control back to the normal world upon receipt of the TSP_PREEMPTED
      SMC. A Group 0 interrupt will immediately preempt execution to EL3 where it
      will be handled. This allows for unified interrupt handling in TSP for both
      GICv3 and GICv2 systems.
      
      Change-Id: I9895344db74b188021e3f6a694701ad272fb40d4
      404dba53
  27. 26 Nov, 2015 1 commit
    • Soby Mathew's avatar
      Remove the IMF_READ_INTERRUPT_ID build option · 54718418
      Soby Mathew authored
      The IMF_READ_INTERRUPT_ID build option enables a feature where the interrupt
      ID of the highest priority pending interrupt is passed as a parameter to the
      interrupt handler registered for that type of interrupt. This additional read
      of highest pending interrupt id from GIC is problematic as it is possible that
      the original interrupt may get deasserted and another interrupt of different
      type maybe become the highest pending interrupt. Hence it is safer to prevent
      such behaviour by removing the IMF_READ_INTERRUPT_ID build option.
      
      The `id` parameter of the interrupt handler `interrupt_type_handler_t` is
      now made a reserved parameter with this patch. It will always contain
      INTR_ID_UNAVAILABLE.
      
      Fixes ARM-software/tf-issues#307
      
      Change-Id: I2173aae1dd37edad7ba6bdfb1a99868635fa34de
      54718418
  28. 09 Oct, 2015 1 commit
    • Varun Wadekar's avatar
      TLKD: pass results with TLK_RESUME_FID function ID · ca15d9bc
      Varun Wadekar authored
      
      
      TLK sends the "preempted" event to the NS world along with an
      identifier for certain use cases. The NS world driver is then
      expected to take appropriate action depending on the identifier
      value. Upon completion, the NS world driver then sends the
      results to TLK (via x1-x3) with the TLK_RESUME_FID function ID.
      
      This patch uses the already present code to pass the results
      from the NS world to TLK for the TLK_RESUME_FID function ID.
      Signed-off-by: default avatarVarun Wadekar <vwadekar@nvidia.com>
      ca15d9bc
  29. 06 Oct, 2015 1 commit
    • Soby Mathew's avatar
      PSCI: Update state only if CPU_OFF is not denied by SPD · 16e05cdb
      Soby Mathew authored
      This patch fixes an issue in the PSCI framework where the affinity info
      state of a core was being set to OFF even when the SPD had denied the
      CPU_OFF request. Now, the state remains set to ON instead.
      
      Fixes ARM-software/tf-issues#323
      
      Change-Id: Ia9042aa41fae574eaa07fd2ce3f50cf8cae1b6fc
      16e05cdb
  30. 30 Sep, 2015 1 commit
    • Varun Wadekar's avatar
      Send power management events to the Trusted OS (TLK) · cb790c5e
      Varun Wadekar authored
      
      
      This patch adds PM handlers to TLKD for the system suspend/resume and
      system poweroff/reset cases. TLK expects all SMCs through a single
      handler, which then fork out into multiple handlers depending on the
      SMC. We tap into the same single entrypoint by restoring the S-EL1
      context before passing the PM event via register 'x0'. On completion
      of the PM event, TLK sends a completion SMC and TLKD then moves on
      with the PM process.
      Signed-off-by: default avatarVarun Wadekar <vwadekar@nvidia.com>
      cb790c5e
  31. 14 Sep, 2015 1 commit
    • Achin Gupta's avatar
      Make generic code work in presence of system caches · 54dc71e7
      Achin Gupta authored
      On the ARMv8 architecture, cache maintenance operations by set/way on the last
      level of integrated cache do not affect the system cache. This means that such a
      flush or clean operation could result in the data being pushed out to the system
      cache rather than main memory. Another CPU could access this data before it
      enables its data cache or MMU. Such accesses could be serviced from the main
      memory instead of the system cache. If the data in the sysem cache has not yet
      been flushed or evicted to main memory then there could be a loss of
      coherency. The only mechanism to guarantee that the main memory will be updated
      is to use cache maintenance operations to the PoC by MVA(See section D3.4.11
      (System level caches) of ARMv8-A Reference Manual (Issue A.g/ARM DDI0487A.G).
      
      This patch removes the reliance of Trusted Firmware on the flush by set/way
      operation to ensure visibility of data in the main memory. Cache maintenance
      operations by MVA are now used instead. The following are the broad category of
      changes:
      
      1. The RW areas of BL2/BL31/BL32 are invalidated by MVA before the C runtime is
         initialised. This ensures that any stale cache lines at any level of cache
         are removed.
      
      2. Updates to global data in runtime firmware (BL31) by the primary CPU are made
         visible to secondary CPUs using a cache clean operation by MVA.
      
      3. Cache maintenance by set/way operations are only used prior to power down.
      
      NOTE: NON-UPSTREAM TRUSTED FIRMWARE CODE SHOULD MAKE EQUIVALENT CHANGES IN
      ORDER TO FUNCTION CORRECTLY ON PLATFORMS WITH SUPPORT FOR SYSTEM CACHES.
      
      Fixes ARM-software/tf-issues#205
      
      Change-Id: I64f1b398de0432813a0e0881d70f8337681f6e9a
      54dc71e7