1. 28 Oct, 2020 1 commit
    • David Horstmann's avatar
      Use constant stack size with RECLAIM_INIT_CODE · 3ed5606b
      David Horstmann authored
      
      
      Currently, when RECLAIM_INIT_CODE is set, the
      stacks are scaled to ensure that the entirety
      of the init section can be reclaimed as stack.
      
      This causes an issue in lib/psci/aarch64/psci_helpers.S,
      where the stack size is used for cache operations in
      psci_do_pwrdown_cache_maintenance(). If the stacks
      are scaled, then the PSCI code may fail to invalidate
      some of the stack memory before power down.
      
      Resizing stacks is also not good for stability in general,
      since code that works with a small number of cores may
      overflow the stack when the number of cores is increased.
      
      Change to make every stack be PLATFORM_STACK_SIZE big,
      and allow the total stack to be smaller than the
      init section.
      
      Any pages of the init section not reclaimed as
      stack will be set to read-only and execute-never,
      for security.
      
      Change-Id: I10b3884981006431f2fcbec3864c81d4a8c246e8
      Signed-off-by: default avatarDavid Horstmann <david.horstmann@arm.com>
      3ed5606b
  2. 10 Aug, 2020 1 commit
    • Alexei Fedorov's avatar
      plat/arm: Reduce size of BL31 binary · fa1fdb22
      Alexei Fedorov authored
      
      
      BL31 binary size is aligned to 4KB because of the
      code in include\plat\arm\common\arm_reclaim_init.ld.S:
          __INIT_CODE_UNALIGNED__ = .;
          . = ALIGN(PAGE_SIZE);
          __INIT_CODE_END__ = .;
      with all the zero data after the last instruction of
      BL31 code to the end of the page.
      This causes increase in size of BL31 binary stored in FIP
      and its loading time by BL2.
      This patch reduces the size of BL31 image by moving
      page alignment from __INIT_CODE_END__ to __STACKS_END__
      which also increases the stack size for secondary CPUs.
      
      Change-Id: Ie2ec503fc774c22c12ec506d74fd3ef2b0b183a9
      Signed-off-by: default avatarAlexei Fedorov <Alexei.Fedorov@arm.com>
      fa1fdb22
  3. 24 Jul, 2020 1 commit
  4. 24 Jun, 2020 1 commit
  5. 24 Feb, 2020 1 commit
    • Petre-Ionut Tudor's avatar
      Read-only xlat tables for BL31 memory · 60e8f3cf
      Petre-Ionut Tudor authored
      
      
      This patch introduces a build flag which allows the xlat tables
      to be mapped in a read-only region within BL31 memory. It makes it
      much harder for someone who has acquired the ability to write to
      arbitrary secure memory addresses to gain control of the
      translation tables.
      
      The memory attributes of the descriptors describing the tables
      themselves are changed to read-only secure data. This change
      happens at the end of BL31 runtime setup. Until this point, the
      tables have read-write permissions. This gives a window of
      opportunity for changes to be made to the tables with the MMU on
      (e.g. reclaiming init code). No changes can be made to the tables
      with the MMU turned on from this point onwards. This change is also
      enabled for sp_min and tspd.
      
      To make all this possible, the base table was moved to .rodata. The
      penalty we pay is that now .rodata must be aligned to the size of
      the base table (512B alignment). Still, this is better than putting
      the base table with the higher level tables in the xlat_table
      section, as that would cost us a full 4KB page.
      
      Changing the tables from read-write to read-only cannot be done with
      the MMU on, as the break-before-make sequence would invalidate the
      descriptor which resolves the level 3 page table where that very
      descriptor is located. This would make the translation required for
      writing the changes impossible, generating an MMU fault.
      
      The caches are also flushed.
      Signed-off-by: default avatarPetre-Ionut Tudor <petre-ionut.tudor@arm.com>
      Change-Id: Ibe5de307e6dc94c67d6186139ac3973516430466
      60e8f3cf
  6. 04 Feb, 2020 1 commit
  7. 27 Jan, 2020 1 commit
    • Madhukar Pappireddy's avatar
      plat/arm: Add support for SEPARATE_NOBITS_REGION · 0c1f197a
      Madhukar Pappireddy authored
      
      
      In order to support SEPARATE_NOBITS_REGION for Arm platforms, we need to load
      BL31 PROGBITS into secure DRAM space and BL31 NOBITS into SRAM. Hence mandate
      the build to require that ARM_BL31_IN_DRAM is enabled as well.
      
      Naturally with SEPARATE_NOBITS_REGION enabled, the BL31 initialization code
      cannot be reclaimed to be used for runtime data such as secondary cpu stacks.
      
      Memory map for BL31 NOBITS region also has to be created.
      
      Change-Id: Ibbc8c9499a32e63fd0957a6e254608fbf6fa90c9
      Signed-off-by: default avatarMadhukar Pappireddy <madhukar.pappireddy@arm.com>
      0c1f197a
  8. 23 Jan, 2020 1 commit
  9. 22 Jan, 2020 1 commit
    • Madhukar Pappireddy's avatar
      plat/arm: Add support for SEPARATE_NOBITS_REGION · d433bbdd
      Madhukar Pappireddy authored
      
      
      In order to support SEPARATE_NOBITS_REGION for Arm platforms, we need to load
      BL31 PROGBITS into secure DRAM space and BL31 NOBITS into SRAM. Hence mandate
      the build to require that ARM_BL31_IN_DRAM is enabled as well.
      
      Naturally with SEPARATE_NOBITS_REGION enabled, the BL31 initialization code
      cannot be reclaimed to be used for runtime data such as secondary cpu stacks.
      
      Memory map for BL31 NOBITS region also has to be created.
      
      Change-Id: Ibd480f82c1dc74e9cbb54eec07d7a8fecbf25433
      Signed-off-by: default avatarMadhukar Pappireddy <madhukar.pappireddy@arm.com>
      d433bbdd
  10. 18 Dec, 2019 1 commit
  11. 28 Jun, 2019 1 commit
  12. 25 Jan, 2019 1 commit
    • Antonio Nino Diaz's avatar
      plat/arm: Sanitise includes · bd9344f6
      Antonio Nino Diaz authored
      
      
      Use full include paths like it is done for common includes.
      
      This cleanup was started in commit d40e0e08283a ("Sanitise includes
      across codebase"), but it only cleaned common files and drivers. This
      patch does the same to Arm platforms.
      
      Change-Id: If982e6450bbe84dceb56d464e282bcf5d6d9ab9b
      Signed-off-by: default avatarAntonio Nino Diaz <antonio.ninodiaz@arm.com>
      bd9344f6
  13. 15 Jan, 2019 1 commit
    • Antonio Nino Diaz's avatar
      plat/arm: Fix header dependencies · 234bc7f8
      Antonio Nino Diaz authored
      
      
      From now on, platform_def.h must include any header with definitions that
      are platform-specific (like arm_def.h) and the included headers mustn't
      include back platform_def.h, and shouldn't be used by other files. Only
      platform_def.h should be included in other files. This will ensure that all
      needed definitions are present, rather than needing to include all the
      headers in all the definitions' headers just in case.
      
      This also prevents problems like cyclic dependencies.
      
      Change-Id: I9d3cf4d1de4b956fa035c79545222697acdaf5ca
      Signed-off-by: default avatarAntonio Nino Diaz <antonio.ninodiaz@arm.com>
      234bc7f8
  14. 04 Jan, 2019 1 commit
    • Antonio Nino Diaz's avatar
      Sanitise includes across codebase · 09d40e0e
      Antonio Nino Diaz authored
      Enforce full include path for includes. Deprecate old paths.
      
      The following folders inside include/lib have been left unchanged:
      
      - include/lib/cpus/${ARCH}
      - include/lib/el3_runtime/${ARCH}
      
      The reason for this change is that having a global namespace for
      includes isn't a good idea. It defeats one of the advantages of having
      folders and it introduces problems that are sometimes subtle (because
      you may not know the header you are actually including if there are two
      of them).
      
      For example, this patch had to be created because two headers were
      called the same way: e0ea0928 ("Fix gpio includes of mt8173 platform
      to avoid collision."). More recently, this patch has had similar
      problems: 46f9b2c3 ("drivers: add tzc380 support").
      
      This problem was introduced in commit 4ecca339
      
       ("Move include and
      source files to logical locations"). At that time, there weren't too
      many headers so it wasn't a real issue. However, time has shown that
      this creates problems.
      
      Platforms that want to preserve the way they include headers may add the
      removed paths to PLAT_INCLUDES, but this is discouraged.
      
      Change-Id: I39dc53ed98f9e297a5966e723d1936d6ccf2fc8f
      Signed-off-by: default avatarAntonio Nino Diaz <antonio.ninodiaz@arm.com>
      09d40e0e
  15. 29 Oct, 2018 1 commit
    • Soby Mathew's avatar
      FVP: Enable PIE for RESET_TO_BL31=1 · fc922ca8
      Soby Mathew authored
      
      
      This patch enabled PIE for FVP when RESET_TO_BL31=1. The references
      to BL31_BASE are replaced by BL31_START as being a symbol exported by
      the linker, will create a dynamic relocation entry in .rela.dyn and
      hence will be fixed up by dynamic linker at runtime. Also, we disable
      RECLAIM_INIT_CODE when PIE is enabled as the init section overlay
      creates some static relocations which cannot be handled by the
      dynamic linker currently.
      
      Change-Id: I86df1b0a8b2a8bbbe7c3f3c0b9a08c86c2963ec0
      Signed-off-by: default avatarSoby Mathew <soby.mathew@arm.com>
      fc922ca8
  16. 26 Oct, 2018 2 commits
    • Roberto Vargas's avatar
      Convert arm_setup_page_tables into a generic helper · 0916c38d
      Roberto Vargas authored
      
      
      This function is not related to Arm platforms and can be reused by other
      platforms if needed.
      
      Change-Id: Ia9c328ce57ce7e917b825a9e09a42b0abb1a53e8
      Co-authored-by: default avatarAntonio Nino Diaz <antonio.ninodiaz@arm.com>
      Signed-off-by: default avatarAntonio Nino Diaz <antonio.ninodiaz@arm.com>
      0916c38d
    • Antonio Nino Diaz's avatar
      xlat: Fix compatibility between v1 and v2 · 03987d01
      Antonio Nino Diaz authored
      
      
      There are several platforms using arm_setup_page_tables(), which is
      supposed to be Arm platform only. This creates several dependency
      problems between platforms.
      
      This patch adds the definition XLAT_TABLES_LIB_V2 to the xlat tables lib
      v2 makefile. This way it is possible to detect from C code which version
      is being used and include the correct header.
      
      The file arm_xlat_tables.h has been renamed to xlat_tables_compat.h and
      moved to a common folder. This way, when in doubt, this header can be
      used to guarantee compatibility, as it includes the correct header based
      on XLAT_TABLES_LIB_V2.
      
      This patch also removes the usage of ARM_XLAT_TABLES_V1 from QEMU (so
      that is now locked in xlat lib v2) and ZynqMP (where it was added as a
      workaround).
      
      Change-Id: Ie1e22a23b44c549603d1402a237a70d0120d3e04
      Signed-off-by: default avatarAntonio Nino Diaz <antonio.ninodiaz@arm.com>
      03987d01
  17. 10 Oct, 2018 1 commit
  18. 03 Oct, 2018 3 commits
    • Daniel Boulby's avatar
      FVP: Reclaim init code for the stack · cb4adb0d
      Daniel Boulby authored
      
      
      Map the initialization code for BL31 to overlap with the memory
      required for the secondary cores stack. Once BL31 has been
      initialized the memory can be remapped to RW data so that it can
      be used for secondary cores stacks. By moving code from .text to
      .text.init the size of the BL31 image is decreased by a page.
      
      Split arm_common.ld.S into two linker scripts, one for tzc_dram
      (arm_tzc_dram.ld.S) and one for reclaiming initialization code
      (arm_reclaim_init.ld.S) so that platforms can chose which memory
      regions they wish to include.
      
      Change-Id: I648e88f3eda1aa71765744cf34343ecda9320b32
      Signed-off-by: default avatarDaniel Boulby <daniel.boulby@arm.com>
      cb4adb0d
    • Daniel Boulby's avatar
      plat/arm: Mark arm platform initialization functions · 4d010d0d
      Daniel Boulby authored
      
      
      Mark the initialization functions found in the BL31 boot sequence
      as __init so they can be reclaimed when no longer needed.
      
      Change-Id: I687a89346419c7710ef5097feaa325d83c527697
      Signed-off-by: default avatarDaniel Boulby <daniel.boulby@arm.com>
      4d010d0d
    • Daniel Boulby's avatar
      Remove unused ROMLIB memory region macro · 8d30b498
      Daniel Boulby authored
      
      
      Remove ARM_MAP_BL_ROMLIB memory region macro as it is now split
      into two regions for code and data
      
      Change-Id: Ic17b5b584933c196db29fe83051d7e0a8e92911c
      Signed-off-by: default avatarDaniel Boulby <daniel.boulby@arm.com>
      8d30b498
  19. 28 Sep, 2018 1 commit
  20. 30 Aug, 2018 1 commit
  21. 06 Aug, 2018 1 commit
  22. 01 Aug, 2018 1 commit
    • Daniel Boulby's avatar
      Fix build for SEPARATE_CODE_AND_RODATA=0 · 2ecaafd2
      Daniel Boulby authored
      
      
      TF won't build since no memory region is specified
      for when SEPARATE_CODE_AND_RODATA=0 it still relies on
      the ARM_MAP_BL_RO_DATA region which is never defined for
      this case. Create memory region combining code and RO data for
      when the build flag SEPARATE_CODE_AND_RODATA=0 to fix this
      
      Change-Id: I6c129eb0833497710cce55e76b8908ce03e0a638
      Signed-off-by: default avatarDaniel Boulby <daniel.boulby@arm.com>
      2ecaafd2
  23. 24 Jul, 2018 1 commit
  24. 11 Jul, 2018 1 commit
  25. 19 Jun, 2018 1 commit
    • Antonio Nino Diaz's avatar
      plat/arm: Migrate AArch64 port to the multi console driver · 88a0523e
      Antonio Nino Diaz authored
      
      
      The old API is deprecated and will eventually be removed.
      
      Arm platforms now use the multi console driver for boot and runtime
      consoles. However, the crash console uses the direct console API because
      it doesn't need any memory access to work. This makes it more robust
      during crashes.
      
      The AArch32 port of the Trusted Firmware doesn't support this new API
      yet, so it is only enabled in AArch64 builds. Because of this, the
      common code must maintain compatibility with both systems. SP_MIN
      doesn't have to be updated because it's only used in AArch32 builds.
      The TSP is only used in AArch64, so it only needs to support the new
      API without keeping support for the old one.
      
      Special care must be taken because of PSCI_SYSTEM_SUSPEND. In Juno, this
      causes the UARTs to reset (except for the one used by the TSP). This
      means that they must be unregistered when suspending and re-registered
      when resuming. This wasn't a problem with the old driver because it just
      restarted the UART, and there were no problems associated with
      registering and unregistering consoles.
      
      The size reserved for BL2 has been increased.
      
      Change-Id: Icefd117dd1eb9c498921181a21318c2d2435c441
      Signed-off-by: default avatarAntonio Nino Diaz <antonio.ninodiaz@arm.com>
      88a0523e
  26. 07 Jun, 2018 1 commit
    • Soby Mathew's avatar
      ARM platforms: Move BL31 below BL2 to enable BL2 overlay · c099cd39
      Soby Mathew authored
      
      
      The patch changes the layout of BL images in memory to enable
      more efficient use of available space. Previously BL31 was loaded
      with the expectation that BL2 memory would be reclaimed by BL32
      loaded in SRAM. But with increasing memory requirements in the
      firmware, we can no longer fit BL32 in SRAM anymore which means the
      BL2 memory is not reclaimed by any runtime image. Positioning BL2
      below BL1-RW and above BL31 means that the BL31 NOBITS can be
      overlaid on BL2 and BL1-RW.
      
      This patch also propogates the same memory layout to BL32 for AArch32
      mode. The reset addresses for the following configurations are also
      changed :
         * When RESET_TO_SP_MIN=1 for BL32 in AArch32 mode
         * When BL2_AT_EL3=1 for BL2
      
      The restriction on BL31 to be only in DRAM when SPM is enabled
      is now removed with this change. The update to the firmware design
      guide for the BL memory layout is done in the following patch.
      
      Change-Id: Icca438e257abe3e4f5a8215f945b9c3f9fbf29c9
      Signed-off-by: default avatarSoby Mathew <soby.mathew@arm.com>
      c099cd39
  27. 15 May, 2018 1 commit
  28. 11 May, 2018 2 commits
    • Antonio Nino Diaz's avatar
      plat/arm: Introduce ARM_LINUX_KERNEL_AS_BL33 build option · b726c169
      Antonio Nino Diaz authored
      
      
      Normally, BL33 needs to contain a boot loader like U-Boot or UEFI that
      eventually gives control to the OS. However, in some cases, this boot
      sequence may be too slow. For example, when doing tests in a
      cycle-accurate emulator, the user may only be interested in the
      interaction between the Trusted Firmware and the OS, not in the boot
      process itself.
      
      The new option ARM_LINUX_KERNEL_AS_BL33 allows BL33 to contain the Linux
      kernel image by changing the value of registers x0-x3 to the values
      expected by the kernel. This option requires the device tree blob (DTB)
      to be present in memory. Its address must be specified in the newly
      introduced ARM_PRELOADED_DTB_BASE build option. For now, it only supports
      AArch64 kernels.
      
      This option is only available when RESET_TO_BL31=1. For this reason
      the BL33 binary must be preloaded in memory and PRELOADED_BL33_BASE must
      be used.
      
      For example, if the kernel is loaded at 0x80080000 and the DTB is loaded
      at address 0x82000000, the firmware could be built like this:
      
          CROSS_COMPILE=aarch64-linux-gnu-  \
          make PLAT=fvp DEBUG=1             \
          RESET_TO_BL31=1                   \
          ARM_LINUX_KERNEL_AS_BL33=1        \
          PRELOADED_BL33_BASE=0x80080000    \
          ARM_PRELOADED_DTB_BASE=0x82000000 \
          all fip
      
      Change-Id: If9dc847c65ae2d0c27b51f0fd44fc06b28497db9
      Signed-off-by: default avatarAntonio Nino Diaz <antonio.ninodiaz@arm.com>
      b726c169
    • Antonio Nino Diaz's avatar
      plat/arm: Migrate AArch64 port to the multi console driver · 2f18aa1f
      Antonio Nino Diaz authored
      
      
      The old API is deprecated and will eventually be removed.
      
      Arm platforms now use the multi console driver for boot and runtime
      consoles. However, the crash console uses the direct console API because
      it doesn't need any memory access to work. This makes it more robust
      during crashes.
      
      The AArch32 port of the Trusted Firmware doesn't support this new API
      yet, so it is only enabled in AArch64 builds. Because of this, the
      common code must maintain compatibility with both systems. SP_MIN
      doesn't have to be updated because it's only used in AArch32 builds.
      The TSP is only used in AArch64, so it only needs to support the new
      API without keeping support for the old one.
      
      Special care must be taken because of PSCI_SYSTEM_SUSPEND. In Juno, this
      causes the UARTs to reset (except for the one used by the TSP). This
      means that they must be unregistered when suspending and re-registered
      when resuming. This wasn't a problem with the old driver because it just
      restarted the UART, and there were no problems associated with
      registering and unregistering consoles.
      
      The size of BL31 has been increased in builds with SPM.
      
      Change-Id: Icefd117dd1eb9c498921181a21318c2d2435c441
      Signed-off-by: default avatarAntonio Nino Diaz <antonio.ninodiaz@arm.com>
      2f18aa1f
  29. 04 May, 2018 1 commit
  30. 01 May, 2018 1 commit
    • Roberto Vargas's avatar
      ARM platforms: Demonstrate mem_protect from el3_runtime · 638b034c
      Roberto Vargas authored
      
      
      Previously mem_protect used to be only supported from BL2. This is not
      helpful in the case when ARM TF-A BL2 is not used. This patch demonstrates
      mem_protect from el3_runtime firmware on ARM Platforms specifically
      when RESET_TO_BL31 or RESET_TO_SP_MIN flag is set as BL2 may be absent
      in these cases. The Non secure DRAM is dynamically mapped into EL3 mmap
      tables temporarily and then the protected regions are then cleared. This
      avoids the need to map the non secure DRAM permanently to BL31/sp_min.
      
      The stack size is also increased, because DYNAMIC_XLAT_TABLES require
      a bigger stack.
      
      Change-Id: Ia44c594192ed5c5adc596c0cff2c7cc18c001fde
      Signed-off-by: default avatarRoberto Vargas <roberto.vargas@arm.com>
      638b034c
  31. 26 Feb, 2018 1 commit
    • Soby Mathew's avatar
      ARM Platforms: Migrate to new BL handover interface · 0c306cc0
      Soby Mathew authored
      
      
      This patch migrates the ARM Standard platforms to the new BL
      handover interface. The arm_blx_early_platform_setup() functions
      are also modified to take in 4 arguments. The `ARM_BL31_PLAT_PARAM_VAL`
      value passed to BL31 from BL2 is now in arg3 in preparation of dynamic
      configuration arguments.
      
      Change-Id: I33e8e61325a19e7a7127b1ff203c3b86921bf153
      Signed-off-by: default avatarSoby Mathew <soby.mathew@arm.com>
      0c306cc0
  32. 03 May, 2017 1 commit
  33. 18 Jan, 2017 2 commits
    • Masahiro Yamada's avatar
      Move BL_COHERENT_RAM_BASE/END defines to common_def.h · 47497053
      Masahiro Yamada authored
      
      
      We have lots of duplicated defines (and comment blocks too).
      Move them to include/plat/common/common_def.h.
      
      While we are here, suffix the end address with _END instead of
      _LIMIT.  The _END is a better fit to indicate the linker-derived
      real end address.
      Signed-off-by: default avatarMasahiro Yamada <yamada.masahiro@socionext.com>
      47497053
    • Masahiro Yamada's avatar
      Use *_END instead of *_LIMIT for linker derived end addresses · ecdc898d
      Masahiro Yamada authored
      
      
      The usage of _LIMIT seems odd here, so rename as follows:
        BL_CODE_LIMIT     --> BL_CODE_END
        BL_RO_DATA_LIMIT  --> BL_RO_DATA_END
        BL1_CODE_LIMIT    --> BL1_CODE_END
        BL1_RO_DATA_LIMIT --> BL1_RO_DATA_END
      
      Basically, we want to use _LIMIT and _END properly as follows:
        *_SIZE + *_MAX_SIZE = *_LIMIT
        *_SIZE + *_SIZE     = *_END
      
      The _LIMIT is generally defined by platform_def.h to indicate the
      platform-dependent memory constraint.  So, its typical usage is
        ASSERT(. <= BL31_LIMIT, "BL31 image has exceeded its limit.")
      in a linker script.
      
      On the other hand, _END is used to indicate the end address of the
      compiled image, i.e. we do not know it until the image is linked.
      
      Here, all of these macros belong to the latter, so should be
      suffixed with _END.
      Signed-off-by: default avatarMasahiro Yamada <yamada.masahiro@socionext.com>
      ecdc898d
  34. 21 Sep, 2016 1 commit
    • Yatharth Kochar's avatar
      ARM platform changes for new version of image loading · a8aa7fec
      Yatharth Kochar authored
      This patch adds changes in ARM platform code to use new
      version of image loading.
      
      Following are the major changes:
        -Refactor the signatures for bl31_early_platform_setup()
         and arm_bl31_early_platform_setup() function to use
         `void *` instead of `bl31_params_t *`.
        -Introduce `plat_arm_bl2_handle_scp_bl2()` to handle
         loading of SCP_BL2 image from BL2.
        -Remove usage of reserve_mem() function from
         `arm_bl1_early_platform_setup()`
        -Extract BL32 & BL33 entrypoint info, from the link list
         passed by BL2, in `arm_bl31_early_platform_setup()`
        -Provides weak definitions for following platform functions:
           plat_get_bl_image_load_info
           plat_get_next_bl_params
           plat_flush_next_bl_params
           bl2_plat_handle_post_image_load
        -Instantiates a descriptor array for ARM platforms
         describing image and entrypoint information for
         `SCP_BL2`, `BL31`, `BL32` and `BL33` images.
      
      All the above changes are conditionally compiled using the
      `LOAD_IMAGE_V2` flag.
      
      Change-Id: I5e88b9785a3df1a2b2bbbb37d85b8e353ca61049
      a8aa7fec
  35. 19 Jul, 2016 1 commit
    • Soby Mathew's avatar
      Cater for preloaded BL33 within plat_get_ns_image_entrypoint() · 48ac1df9
      Soby Mathew authored
      The PRELOADED_BL33_BASE build option allows to preload a BL33 and bypass its
      loading by BL2. In ARM standard platforms, the conditional behaviour of
      PRELOADED_BL33_BASE is moved within the implementation of
      `plat_get_ns_image_entrypoint()` so that all callers may benefit from this
      feature.
      
      Change-Id: Iea060e204ec72f8081087837854535c4e320da4e
      48ac1df9