1. 19 Oct, 2015 1 commit
    • Sandrine Bailleux's avatar
      Make CASSERT() macro callable from anywhere · c17a4dc3
      Sandrine Bailleux authored
      The CASSERT() macro introduces a typedef for the sole purpose of
      triggering a compilation error if the condition to check is false.
      This typedef is not used afterwards. As a consequence, when the
      CASSERT() macro is called from withing a function block, the compiler
      complains and outputs the following error message:
      
        error: typedef 'msg' locally defined but not used [-Werror=unused-local-typedefs]
      
      This patch adds the "unused" attribute for the aforementioned
      typedef. This silences the compiler warning and thus makes the
      CASSERT() macro callable from within function blocks as well.
      
      Change-Id: Ie36b58fcddae01a21584c48bb6ef43ec85590479
      c17a4dc3
  2. 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
  3. 11 Sep, 2015 1 commit
    • Andrew Thoelke's avatar
      Re-design bakery lock memory allocation and algorithm · ee7b35c4
      Andrew Thoelke authored
      This patch unifies the bakery lock api's across coherent and normal
      memory implementation of locks by using same data type `bakery_lock_t`
      and similar arguments to functions.
      
      A separate section `bakery_lock` has been created and used to allocate
      memory for bakery locks using `DEFINE_BAKERY_LOCK`. When locks are
      allocated in normal memory, each lock for a core has to spread
      across multiple cache lines. By using the total size allocated in a
      separate cache line for a single core at compile time, the memory for
      other core locks is allocated at link time by multiplying the single
      core locks size with (PLATFORM_CORE_COUNT - 1). The normal memory lock
      algorithm now uses lock address instead of the `id` in the per_cpu_data.
      For locks allocated in coherent memory, it moves locks from
      tzfw_coherent_memory to bakery_lock section.
      
      The bakery locks are allocated as part of bss or in coherent memory
      depending on usage of coherent memory. Both these regions are
      initialised to zero as part of run_time_init before locks are used.
      Hence, bakery_lock_init() is made an empty function as the lock memory
      is already initialised to zero.
      
      The above design lead to the removal of psci bakery locks from
      non_cpu_power_pd_node to psci_locks.
      
      NOTE: THE BAKERY LOCK API WHEN USE_COHERENT_MEM IS NOT SET HAS CHANGED.
      THIS IS A BREAKING CHANGE FOR ALL PLATFORM PORTS THAT ALLOCATE BAKERY
      LOCKS IN NORMAL MEMORY.
      
      Change-Id: Ic3751c0066b8032dcbf9d88f1d4dc73d15f61d8b
      ee7b35c4
  4. 24 Aug, 2015 1 commit
  5. 05 Aug, 2015 2 commits
  6. 24 Jul, 2015 1 commit
    • Varun Wadekar's avatar
      Add "Project Denver" CPU support · 3a8c55f6
      Varun Wadekar authored
      
      
      Denver is NVIDIA's own custom-designed, 64-bit, dual-core CPU which is
      fully ARMv8 architecture compatible.  Each of the two Denver cores
      implements a 7-way superscalar microarchitecture (up to 7 concurrent
      micro-ops can be executed per clock), and includes a 128KB 4-way L1
      instruction cache, a 64KB 4-way L1 data cache, and a 2MB 16-way L2
      cache, which services both cores.
      
      Denver implements an innovative process called Dynamic Code Optimization,
      which optimizes frequently used software routines at runtime into dense,
      highly tuned microcode-equivalent routines. These are stored in a
      dedicated, 128MB main-memory-based optimization cache. After being read
      into the instruction cache, the optimized micro-ops are executed,
      re-fetched and executed from the instruction cache as long as needed and
      capacity allows.
      
      Effectively, this reduces the need to re-optimize the software routines.
      Instead of using hardware to extract the instruction-level parallelism
      (ILP) inherent in the code, Denver extracts the ILP once via software
      techniques, and then executes those routines repeatedly, thus amortizing
      the cost of ILP extraction over the many execution instances.
      
      Denver also features new low latency power-state transitions, in addition
      to extensive power-gating and dynamic voltage and clock scaling based on
      workloads.
      Signed-off-by: default avatarVarun Wadekar <vwadekar@nvidia.com>
      3a8c55f6
  7. 27 Apr, 2015 2 commits
    • Dan Handley's avatar
      Add header guards to asm macro files · e2bf57f8
      Dan Handley authored
      Some assembly files containing macros are included like header files
      into other assembly files. This will cause assembler errors if they
      are included multiple times.
      
      Add header guards to assembly macro files to avoid assembler errors.
      
      Change-Id: Ia632e767ed7df7bf507b294982b8d730a6f8fe69
      e2bf57f8
    • Dan Handley's avatar
      Remove use of PLATFORM_CACHE_LINE_SIZE · ce4c820d
      Dan Handley authored
      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
      ce4c820d
  8. 31 Mar, 2015 1 commit
  9. 27 Mar, 2015 2 commits
    • Soby Mathew's avatar
      Remove the `owner` field in bakery_lock_t data structure · 548579f5
      Soby Mathew authored
      This patch removes the `owner` field in bakery_lock_t structure which
      is the data structure used in the bakery lock implementation that uses
      coherent memory. The assertions to protect against recursive lock
      acquisition were based on the 'owner' field. They are now done based
      on the bakery lock ticket number. These assertions are also added
      to the bakery lock implementation that uses normal memory as well.
      
      Change-Id: If4850a00dffd3977e218c0f0a8d145808f36b470
      548579f5
    • Soby Mathew's avatar
      Optimize the bakery lock structure for coherent memory · 1c9573a1
      Soby Mathew authored
      This patch optimizes the data structure used with the bakery lock
      implementation for coherent memory to save memory and minimize memory
      accesses. These optimizations were already part of the bakery lock
      implementation for normal memory and this patch now implements
      it for the coherent memory implementation as well. Also
      included in the patch is a cleanup to use the do-while loop while
      waiting for other contenders to finish choosing their tickets.
      
      Change-Id: Iedb305473133dc8f12126726d8329b67888b70f1
      1c9573a1
  10. 18 Mar, 2015 1 commit
  11. 16 Mar, 2015 1 commit
  12. 26 Jan, 2015 1 commit
    • Yatharth Kochar's avatar
      Call reset handlers upon BL3-1 entry. · 79a97b2e
      Yatharth Kochar authored
      This patch adds support to call the reset_handler() function in BL3-1 in the
      cold and warm boot paths when another Boot ROM reset_handler() has already run.
      
      This means the BL1 and BL3-1 versions of the CPU and platform specific reset
      handlers may execute different code to each other. This enables a developer to
      perform additional actions or undo actions already performed during the first
      call of the reset handlers e.g. apply additional errata workarounds.
      
      Typically, the reset handler will be first called from the BL1 Boot ROM. Any
      additional functionality can be added to the reset handler when it is called
      from BL3-1 resident in RW memory. The constant FIRST_RESET_HANDLER_CALL is used
      to identify whether this is the first version of the reset handler code to be
      executed or an overridden version of the code.
      
      The Cortex-A57 errata workarounds are applied only if they have not already been
      applied.
      
      Fixes ARM-software/tf-issue#275
      
      Change-Id: Id295f106e4fda23d6736debdade2ac7f2a9a9053
      79a97b2e
  13. 23 Jan, 2015 1 commit
    • Soby Mathew's avatar
      Return success if an interrupt is seen during PSCI CPU_SUSPEND · 22f08973
      Soby Mathew authored
      This patch adds support to return SUCCESS if a pending interrupt is
      detected during a CPU_SUSPEND call to a power down state. The check
      is performed as late as possible without losing the ability to return
      to the caller. This reduces the overhead incurred by a CPU in
      undergoing a complete power cycle when a wakeup interrupt is already
      pending.
      
      Fixes ARM-Software/tf-issues#102
      
      Change-Id: I1aff04a74b704a2f529734428030d1d10750fd4b
      22f08973
  14. 22 Jan, 2015 2 commits
    • Soby Mathew's avatar
      Move bakery algorithm implementation out of coherent memory · 8c5fe0b5
      Soby Mathew authored
      This patch moves the bakery locks out of coherent memory to normal memory.
      This implies that the lock information needs to be placed on a separate cache
      line for each cpu. Hence the bakery_lock_info_t structure is allocated in the
      per-cpu data so as to minimize memory wastage. A similar platform per-cpu
      data is introduced for the platform locks.
      
      As a result of the above changes, the bakery lock api is completely changed.
      Earlier, a reference to the lock structure was passed to the lock implementation.
      Now a unique-id (essentially an index into the per-cpu data array) and an offset
      into the per-cpu data for bakery_info_t needs to be passed to the lock
      implementation.
      
      Change-Id: I1e76216277448713c6c98b4c2de4fb54198b39e0
      8c5fe0b5
    • Soby Mathew's avatar
      Add macros for domain specific barriers. · 5b1cd43b
      Soby Mathew authored
      This patch adds helper macros for barrier operations that specify
      the type of barrier (dmb, dsb) and the shareability domain (system,
      inner-shareable) it affects.
      
      Change-Id: I4bf95103e79da212c4fbdbc13d91ad8ac385d9f5
      5b1cd43b
  15. 07 Jan, 2015 1 commit
    • Sandrine Bailleux's avatar
      Prevent optimisation of sysregs accessors calls · 36e2fd01
      Sandrine Bailleux authored
      Calls to system register read accessors functions may be optimised
      out by the compiler if called twice in a row for the same register.
      This is because the compiler is not aware that the result from
      the instruction may be modified by external agents. Therefore, if
      nothing modifies the register between the 2 reads as far as the
      compiler knows then it might consider that it is useless to read
      it twice and emit only 1 call.
      
      This behaviour is faulty for registers that may not have the same
      value if read twice in succession. E.g.: counters, timer
      control/countdown registers, GICv3 interrupt status registers and
      so on.
      
      The same problem happens for calls to system register write
      accessors functions. The compiler might optimise out some calls
      if it considers that it will produce the same result. Again, this
      behaviour is faulty for cases where intermediate writes to these
      registers make a difference in the system.
      
      This patch fixes the problem by making these assembly register
      accesses volatile.
      
      Fixes ARM-software/tf-issues#273
      
      Change-Id: I33903bc4cc4eea8a8d87bc2c757909fbb0138925
      36e2fd01
  16. 04 Dec, 2014 1 commit
    • Soby Mathew's avatar
      Fix the array size of mpidr_aff_map_nodes_t. · 235585b1
      Soby Mathew authored
      This patch fixes the array size of mpidr_aff_map_nodes_t which
      was less by one element.
      
      Fixes ARM-software/tf-issues#264
      
      Change-Id: I48264f6f9e7046a3d0f4cbcd63b9ba49657e8818
      235585b1
  17. 29 Oct, 2014 1 commit
    • Soby Mathew's avatar
      Apply errata workarounds only when major/minor revisions match. · 7395a725
      Soby Mathew authored
      Prior to this patch, the errata workarounds were applied for any version
      of the CPU in the release build and in the debug build an assert
      failure resulted when the revision did not match. This patch applies
      errata workarounds in the Cortex-A57 reset handler only if the 'variant'
      and 'revision' fields read from the MIDR_EL1 match. In the debug build,
      a warning message is printed for each errata workaround which is not
      applied.
      
      The patch modifies the register usage in 'reset_handler` so
      as to adhere to ARM procedure calling standards.
      
      Fixes ARM-software/tf-issues#242
      
      Change-Id: I51b1f876474599db885afa03346e38a476f84c29
      7395a725
  18. 25 Sep, 2014 1 commit
    • Soby Mathew's avatar
      Create BL stage specific translation tables · d0ecd979
      Soby Mathew authored
      This patch uses the IMAGE_BL<x> constants to create translation tables specific
      to a boot loader stage. This allows each stage to create mappings only for areas
      in the memory map that it needs.
      
      Fixes ARM-software/tf-issues#209
      
      Change-Id: Ie4861407ddf9317f0fb890fc7575eaa88d0de51c
      d0ecd979
  19. 16 Sep, 2014 1 commit
  20. 02 Sep, 2014 1 commit
    • Soby Mathew's avatar
      Reset CNTVOFF_EL2 register before exit into EL1 on warm boot · 14c0526b
      Soby Mathew authored
      This patch resets the value of CNTVOFF_EL2 before exit to EL1 on
      warm boot. This needs to be done if only the Trusted Firmware exits
      to EL1 instead of EL2, otherwise the hypervisor would be responsible
      for this.
      
      Fixes ARM-software/tf-issues#240
      
      Change-Id: I79d54831356cf3215bcf1f251c373bd8f89db0e0
      14c0526b
  21. 21 Aug, 2014 1 commit
    • Sandrine Bailleux's avatar
      Juno: Implement initial platform port · 01b916bf
      Sandrine Bailleux authored
      This patch adds the initial port of the ARM Trusted Firmware on the Juno
      development platform. This port does not support a BL3-2 image or any PSCI APIs
      apart from PSCI_VERSION and PSCI_CPU_ON. It enables workarounds for selected
      Cortex-A57 (#806969 & #813420) errata and implements the workaround for a Juno
      platform errata (Defect id 831273).
      
      Change-Id: Ib3d92df3af53820cfbb2977582ed0d7abf6ef893
      01b916bf
  22. 20 Aug, 2014 4 commits
    • Soby Mathew's avatar
      Add support for selected Cortex-A57 errata workarounds · d9bdaf2d
      Soby Mathew authored
      This patch adds workarounds for selected errata which affect the Cortex-A57 r0p0
      part. Each workaround has a build time flag which should be used by the platform
      port to enable or disable the corresponding workaround. The workarounds are
      disabled by default. An assertion is raised if the platform enables a workaround
      which does not match the CPU revision at runtime.
      
      Change-Id: I9ae96b01c6ff733d04dc733bd4e67dbf77b29fb0
      d9bdaf2d
    • Soby Mathew's avatar
      Add CPU specific crash reporting handlers · d3f70af6
      Soby Mathew authored
      This patch adds handlers for dumping Cortex-A57 and Cortex-A53 specific register
      state to the CPU specific operations framework. The contents of CPUECTLR_EL1 are
      dumped currently.
      
      Change-Id: I63d3dbfc4ac52fef5e25a8cf6b937c6f0975c8ab
      d3f70af6
    • Soby Mathew's avatar
      Add CPU specific power management operations · add40351
      Soby Mathew authored
      This patch adds CPU core and cluster power down sequences to the CPU specific
      operations framework introduced in a earlier patch. Cortex-A53, Cortex-A57 and
      generic AEM sequences have been added. The latter is suitable for the
      Foundation and Base AEM FVPs. A pointer to each CPU's operations structure is
      saved in the per-cpu data so that it can be easily accessed during power down
      seqeunces.
      
      An optional platform API has been introduced to allow a platform to disable the
      Accelerator Coherency Port (ACP) during a cluster power down sequence. The weak
      definition of this function (plat_disable_acp()) does not take any action. It
      should be overriden with a strong definition if the ACP is present on a
      platform.
      
      Change-Id: I8d09bd40d2f528a28d2d3f19b77101178778685d
      add40351
    • Soby Mathew's avatar
      Introduce framework for CPU specific operations · 9b476841
      Soby Mathew authored
      This patch introduces a framework which will allow CPUs to perform
      implementation defined actions after a CPU reset, during a CPU or cluster power
      down, and when a crash occurs. CPU specific reset handlers have been implemented
      in this patch. Other handlers will be implemented in subsequent patches.
      
      Also moved cpu_helpers.S to the new directory lib/cpus/aarch64/.
      
      Change-Id: I1ca1bade4d101d11a898fb30fea2669f9b37b956
      9b476841
  23. 14 Aug, 2014 1 commit
    • Dan Handley's avatar
      Move IO storage source to drivers directory · 935db693
      Dan Handley authored
      Move the remaining IO storage source file (io_storage.c) from the
      lib to the drivers directory. This requires that platform ports
      explicitly add this file to the list of source files.
      
      Also move the IO header files to a new sub-directory, include/io.
      
      Change-Id: I862b1252a796b3bcac0d93e50b11e7fb2ded93d6
      935db693
  24. 28 Jul, 2014 1 commit
    • Achin Gupta's avatar
      Simplify management of SCTLR_EL3 and SCTLR_EL1 · ec3c1003
      Achin Gupta authored
      This patch reworks the manner in which the M,A, C, SA, I, WXN & EE bits of
      SCTLR_EL3 & SCTLR_EL1 are managed. The EE bit is cleared immediately after reset
      in EL3. The I, A and SA bits are set next in EL3 and immediately upon entry in
      S-EL1. These bits are no longer managed in the blX_arch_setup() functions. They
      do not have to be saved and restored either. The M, WXN and optionally the C
      bit are set in the enable_mmu_elX() function. This is done during both the warm
      and cold boot paths.
      
      Fixes ARM-software/tf-issues#226
      
      Change-Id: Ie894d1a07b8697c116960d858cd138c50bc7a069
      ec3c1003
  25. 19 Jul, 2014 1 commit
    • Achin Gupta's avatar
      Make enablement of the MMU more flexible · afff8cbd
      Achin Gupta authored
      This patch adds a 'flags' parameter to each exception level specific function
      responsible for enabling the MMU. At present only a single flag which indicates
      whether the data cache should also be enabled is implemented. Subsequent patches
      will use this flag when enabling the MMU in the warm boot paths.
      
      Change-Id: I0eafae1e678c9ecc604e680851093f1680e9cefa
      afff8cbd
  26. 09 Jul, 2014 1 commit
    • Lin Ma's avatar
      Calculate TCR bits based on VA and PA · 73ad2572
      Lin Ma authored
      Currently the TCR bits are hardcoded in xlat_tables.c. In order to
      map higher physical address into low virtual address, the TCR bits
      need to be configured accordingly.
      
      This patch is to save the max VA and PA and calculate the TCR.PS/IPS
      and t0sz bits in init_xlat_tables function.
      
      Change-Id: Ia7a58e5372b20200153057d457f4be5ddbb7dae4
      73ad2572
  27. 24 Jun, 2014 2 commits
    • Andrew Thoelke's avatar
      Inline the mmio accessor functions · 5e113753
      Andrew Thoelke authored
      Making the simple mmio_read_*() and mmio_write_*() functions inline
      saves 360 bytes of code in FVP release build.
      
      Fixes ARM-software/tf-issues#210
      
      Change-Id: I65134f9069f3b2d8821d882daaa5fdfe16355e2f
      5e113753
    • Juan Castillo's avatar
      Remove all checkpatch errors from codebase · 4f2104ff
      Juan Castillo authored
      Exclude stdlib files because they do not follow kernel code style.
      
      Fixes ARM-software/tf-issues#73
      
      Change-Id: I4cfafa38ab436f5ab22c277cb38f884346a267ab
      4f2104ff
  28. 23 Jun, 2014 2 commits
    • Andrew Thoelke's avatar
      Remove calling CPU mpidr from bakery lock API · 634ec6c2
      Andrew Thoelke authored
      The bakery lock code currently expects the calling code to pass
      the MPIDR_EL1 of the current CPU.
      
      This is not always done correctly. Also the change to provide
      inline access to system registers makes it more efficient for the
      bakery lock code to obtain the MPIDR_EL1 directly.
      
      This change removes the mpidr parameter from the bakery lock
      interface, and results in a code reduction of 160 bytes for the
      ARM FVP port.
      
      Fixes ARM-software/tf-issues#213
      
      Change-Id: I7ec7bd117bcc9794a0d948990fcf3336a367d543
      634ec6c2
    • Andrew Thoelke's avatar
      Initialise CPU contexts from entry_point_info · 167a9357
      Andrew Thoelke authored
      Consolidate all BL3-1 CPU context initialization for cold boot, PSCI
      and SPDs into two functions:
      *  The first uses entry_point_info to initialize the relevant
         cpu_context for first entry into a lower exception level on a CPU
      *  The second populates the EL1 and EL2 system registers as needed
         from the cpu_context to ensure correct entry into the lower EL
      
      This patch alters the way that BL3-1 determines which exception level
      is used when first entering EL1 or EL2 during cold boot - this is now
      fully determined by the SPSR value in the entry_point_info for BL3-3,
      as set up by the platform code in BL2 (or otherwise provided to BL3-1).
      
      In the situation that EL1 (or svc mode) is selected for a processor
      that supports EL2, the context management code will now configure all
      essential EL2 register state to ensure correct execution of EL1. This
      allows the platform code to run non-secure EL1 payloads directly
      without requiring a small EL2 stub or OS loader.
      
      Change-Id: If9fbb2417e82d2226e47568203d5a369f39d3b0f
      167a9357
  29. 10 Jun, 2014 1 commit
    • Andrew Thoelke's avatar
      Make system register functions inline assembly · 5c3272a7
      Andrew Thoelke authored
      Replace the current out-of-line assembler implementations of
      the system register and system instruction operations with
      inline assembler.
      
      This enables better compiler optimisation and code generation
      when accessing system registers.
      
      Fixes ARM-software/tf-issues#91
      
      Change-Id: I149af3a94e1e5e5140a3e44b9abfc37ba2324476
      5c3272a7
  30. 02 Jun, 2014 1 commit
    • Lin Ma's avatar
      Enable mapping higher physical address · f984ce84
      Lin Ma authored
      Current ATF uses a direct physical-to-virtual mapping, that is, a physical
      address is mapped to the same address in the virtual space. For example,
      physical address 0x8000_0000 is mapped to 0x8000_0000 virtual. This
      approach works fine for FVP as all its physical addresses fall into 0 to
      4GB range. But for other platform where all I/O addresses are 48-bit long,
      If we follow the same direct mapping, we would need virtual address range
      from 0 to 0x8fff_ffff_ffff, which is about 144TB. This requires a
      significant amount of memory for MMU tables and it is not necessary to use
      that much virtual space in ATF.
      
      The patch is to enable mapping a physical address range to an arbitrary
      virtual address range (instead of flat mapping)
      Changed "base" to "base_va" and added "base_pa" in mmap_region_t and
      modified functions such as mmap_add_region and init_xlation_table etc.
      Fixes ARM-software/tf-issues#158
      f984ce84
  31. 23 May, 2014 1 commit
    • 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