1. 08 Mar, 2017 2 commits
    • Antonio Nino Diaz's avatar
      Apply workaround for errata 813419 of Cortex-A57 · ccbec91c
      Antonio Nino Diaz authored
      
      
      TLBI instructions for EL3 won't have the desired effect under specific
      circumstances in Cortex-A57 r0p0. The workaround is to execute DSB and
      TLBI twice each time.
      
      Even though this errata is only needed in r0p0, the current errata
      framework is not prepared to apply run-time workarounds. The current one
      is always applied if compiled in, regardless of the CPU or its revision.
      
      This errata has been enabled for Juno.
      
      The `DSB` instruction used when initializing the translation tables has
      been changed to `DSB ISH` as an optimization and to be consistent with
      the barriers used for the workaround.
      
      Change-Id: Ifc1d70b79cb5e0d87e90d88d376a59385667d338
      Signed-off-by: default avatarAntonio Nino Diaz <antonio.ninodiaz@arm.com>
      ccbec91c
    • Antonio Nino Diaz's avatar
      Add dynamic region support to xlat tables lib v2 · 0b64f4ef
      Antonio Nino Diaz authored
      
      
      Added APIs to add and remove regions to the translation tables
      dynamically while the MMU is enabled. Only static regions are allowed
      to overlap other static ones (for backwards compatibility).
      
      A new private attribute (MT_DYNAMIC / MT_STATIC) has been added to
      flag each region as such.
      
      The dynamic mapping functionality can be enabled or disabled when
      compiling by setting the build option PLAT_XLAT_TABLES_DYNAMIC to 1
      or 0. This can be done per-image.
      
      TLB maintenance code during dynamic table mapping and unmapping has
      also been added.
      
      Fixes ARM-software/tf-issues#310
      
      Change-Id: I19e8992005c4292297a382824394490c5387aa3b
      Signed-off-by: default avatarAntonio Nino Diaz <antonio.ninodiaz@arm.com>
      0b64f4ef
  2. 02 Mar, 2017 1 commit
  3. 28 Feb, 2017 1 commit
  4. 23 Feb, 2017 1 commit
  5. 22 Feb, 2017 2 commits
    • Varun Wadekar's avatar
      Tegra: init normal/crash console for platforms · e1084216
      Varun Wadekar authored
      
      
      The BL2 fills in the UART controller ID to be used as the normal as
      well as the crash console on Tegra platforms. The controller ID to
      UART controller base address mapping is handled by each Tegra SoC
      the base addresses might change across Tegra chips.
      
      This patch adds the handler to parse the platform params to get the
      UART ID for the per-soc handlers.
      
      Change-Id: I4d167b20a59aaf52a31e2a8edf94d8d6f89598fa
      Signed-off-by: default avatarVarun Wadekar <vwadekar@nvidia.com>
      e1084216
    • Varun Wadekar's avatar
      Tegra: add tzdram_base to plat_params_from_bl2 struct · e0d4158c
      Varun Wadekar authored
      
      
      This patch adds another member, tzdram_base, to the plat_params_from_bl2 struct
      in order to store the TZDRAM carveout base address used to load the Trusted OS.
      The monitor programs the memory controller with the TZDRAM base and size in order
      to deny any accesses from the NS world.
      
      Change-Id: If39b8674d548175d7ccb6525c18d196ae8a8506c
      Signed-off-by: default avatarVarun Wadekar <vwadekar@nvidia.com>
      e0d4158c
  6. 14 Feb, 2017 1 commit
    • Jeenu Viswambharan's avatar
      Introduce locking primitives using CAS instruction · c877b414
      Jeenu Viswambharan authored
      
      
      The ARMv8v.1 architecture extension has introduced support for far
      atomics, which includes compare-and-swap. Compare and Swap instruction
      is only available for AArch64.
      
      Introduce build options to choose the architecture versions to target
      ARM Trusted Firmware:
      
        - ARM_ARCH_MAJOR: selects the major version of target ARM
          Architecture. Default value is 8.
      
        - ARM_ARCH_MINOR: selects the minor version of target ARM
          Architecture. Default value is 0.
      
      When:
      
        (ARM_ARCH_MAJOR > 8) || ((ARM_ARCH_MAJOR == 8) && (ARM_ARCH_MINOR >= 1)),
      
      for AArch64, Compare and Swap instruction is used to implement spin
      locks. Otherwise, the implementation falls back to using
      load-/store-exclusive instructions.
      
      Update user guide, and introduce a section in Firmware Design guide to
      summarize support for features introduced in ARMv8 Architecture
      Extensions.
      
      Change-Id: I73096a0039502f7aef9ec6ab3ae36680da033f16
      Signed-off-by: default avatarJeenu Viswambharan <jeenu.viswambharan@arm.com>
      c877b414
  7. 13 Feb, 2017 2 commits
    • David Cunado's avatar
      Migrate to Linaro Release 16.12 · e361cf3b
      David Cunado authored
      
      
      This Linaro release updates both the binaries and the toolchain:
      Linaro binaries upgraded 16.06 --> 16.12
      AArch64 compiler upgraded 15.05 (gcc 4.9) --> 5.3-2015.05 (gcc 5.3)
      AArch32 compiler upgraded 15.05 (gcc 4.9) --> 5.3-2015.05 (gcc 5.3)
      
      The ARM TF codebase has been tested against these new binaries. This patch
      updates the User Guide to reflect that the 16.12 release is now a supported
      Linaro Release.
      
      Change-Id: I6247e820f591df7d05df4f622ee45a3abf2c2d72
      Signed-off-by: default avatarDavid Cunado <david.cunado@arm.com>
      e361cf3b
    • dp-arm's avatar
      PSCI: Decouple PSCI stat residency calculation from PMF · 04c1db1e
      dp-arm authored
      
      
      This patch introduces the following three platform interfaces:
      
      * void plat_psci_stat_accounting_start(const psci_power_state_t *state_info)
      
        This is an optional hook that platforms can implement in order
        to perform accounting before entering a low power state.  This
        typically involves capturing a timestamp.
      
      * void plat_psci_stat_accounting_stop(const psci_power_state_t *state_info)
      
        This is an optional hook that platforms can implement in order
        to perform accounting after exiting from a low power state.  This
        typically involves capturing a timestamp.
      
      * u_register_t plat_psci_stat_get_residency(unsigned int lvl,
      	const psci_power_state_t *state_info,
      	unsigned int last_cpu_index)
      
        This is an optional hook that platforms can implement in order
        to calculate the PSCI stat residency.
      
      If any of these interfaces are overridden by the platform, it is
      recommended that all of them are.
      
      By default `ENABLE_PSCI_STAT` is disabled.  If `ENABLE_PSCI_STAT`
      is set but `ENABLE_PMF` is not set then an alternative PSCI stat
      collection backend must be provided.  If both are set, then default
      weak definitions of these functions are provided, using PMF to
      calculate the residency.
      
      NOTE: Previously, platforms did not have to explicitly set
      `ENABLE_PMF` since this was automatically done by the top-level
      Makefile.
      
      Change-Id: I17b47804dea68c77bc284df15ee1ccd66bc4b79b
      Signed-off-by: default avatardp-arm <dimitris.papastamos@arm.com>
      04c1db1e
  8. 10 Feb, 2017 1 commit
    • David Cunado's avatar
      Update AEM and Cortex Models versions · dbd1ab8e
      David Cunado authored
      
      
      AEMv8-A Model release v8.2 has been made available and Trusted Firmware
      has been tested against these versions as part of its CI system. This
      patch updates the user guide documentation to reflect the version of AEM
      and Cortex Models that Trusted Firmware has been tested against.
      
      Also, the Linaro Release Notes link was broken and this patch updates the
      link.
      
      Change-Id: I88729cef909a69fff629036f480fd6168ad7dc9a
      Signed-off-by: default avatarDavid Cunado <david.cunado@arm.com>
      dbd1ab8e
  9. 06 Feb, 2017 2 commits
    • Douglas Raillard's avatar
      Introduce unified API to zero memory · 308d359b
      Douglas Raillard authored
      
      
      Introduce zeromem_dczva function on AArch64 that can handle unaligned
      addresses and make use of DC ZVA instruction to zero a whole block at a
      time. This zeroing takes place directly in the cache to speed it up
      without doing external memory access.
      
      Remove the zeromem16 function on AArch64 and replace it with an alias to
      zeromem. This zeromem16 function is now deprecated.
      
      Remove the 16-bytes alignment constraint on __BSS_START__ in
      firmware-design.md as it is now not mandatory anymore (it used to comply
      with zeromem16 requirements).
      
      Change the 16-bytes alignment constraints in SP min's linker script to a
      8-bytes alignment constraint as the AArch32 zeromem implementation is now
      more efficient on 8-bytes aligned addresses.
      
      Introduce zero_normalmem and zeromem helpers in platform agnostic header
      that are implemented this way:
      * AArch32:
      	* zero_normalmem: zero using usual data access
      	* zeromem: alias for zero_normalmem
      * AArch64:
      	* zero_normalmem: zero normal memory  using DC ZVA instruction
      	                  (needs MMU enabled)
      	* zeromem: zero using usual data access
      
      Usage guidelines: in most cases, zero_normalmem should be preferred.
      
      There are 2 scenarios where zeromem (or memset) must be used instead:
      * Code that must run with MMU disabled (which means all memory is
        considered device memory for data accesses).
      * Code that fills device memory with null bytes.
      
      Optionally, the following rule can be applied if performance is
      important:
      * Code zeroing small areas (few bytes) that are not secrets should use
        memset to take advantage of compiler optimizations.
      
        Note: Code zeroing security-related critical information should use
        zero_normalmem/zeromem instead of memset to avoid removal by
        compilers' optimizations in some cases or misbehaving versions of GCC.
      
      Fixes ARM-software/tf-issues#408
      
      Change-Id: Iafd9663fc1070413c3e1904e54091cf60effaa82
      Signed-off-by: default avatarDouglas Raillard <douglas.raillard@arm.com>
      308d359b
    • Masahiro Yamada's avatar
      zynqmp: remove RESET_TO_BL31=1 from build instruction · 4fff02c6
      Masahiro Yamada authored
      
      
      RESET_TO_BL31=1 is specified by plat/xilinx/zynqmp/platform.mk with
      "override" directive.  So, RESET_TO_BL31=1 is guaranteed without any
      operation on users' side.
      Signed-off-by: default avatarMasahiro Yamada <yamada.masahiro@socionext.com>
      4fff02c6
  10. 30 Jan, 2017 1 commit
    • Jeenu Viswambharan's avatar
      Report errata workaround status to console · 10bcd761
      Jeenu Viswambharan authored
      
      
      The errata reporting policy is as follows:
      
        - If an errata workaround is enabled:
      
          - If it applies (i.e. the CPU is affected by the errata), an INFO
            message is printed, confirming that the errata workaround has been
            applied.
      
          - If it does not apply, a VERBOSE message is printed, confirming
            that the errata workaround has been skipped.
      
        - If an errata workaround is not enabled, but would have applied had
          it been, a WARN message is printed, alerting that errata workaround
          is missing.
      
      The CPU errata messages are printed by both BL1 (primary CPU only) and
      runtime firmware on debug builds, once for each CPU/errata combination.
      
      Relevant output from Juno r1 console when ARM Trusted Firmware is built
      with PLAT=juno LOG_LEVEL=50 DEBUG=1:
      
        VERBOSE: BL1: cortex_a57: errata workaround for 806969 was not applied
        VERBOSE: BL1: cortex_a57: errata workaround for 813420 was not applied
        INFO:    BL1: cortex_a57: errata workaround for disable_ldnp_overread was applied
        WARNING: BL1: cortex_a57: errata workaround for 826974 was missing!
        WARNING: BL1: cortex_a57: errata workaround for 826977 was missing!
        WARNING: BL1: cortex_a57: errata workaround for 828024 was missing!
        WARNING: BL1: cortex_a57: errata workaround for 829520 was missing!
        WARNING: BL1: cortex_a57: errata workaround for 833471 was missing!
        ...
        VERBOSE: BL31: cortex_a57: errata workaround for 806969 was not applied
        VERBOSE: BL31: cortex_a57: errata workaround for 813420 was not applied
        INFO:    BL31: cortex_a57: errata workaround for disable_ldnp_overread was applied
        WARNING: BL31: cortex_a57: errata workaround for 826974 was missing!
        WARNING: BL31: cortex_a57: errata workaround for 826977 was missing!
        WARNING: BL31: cortex_a57: errata workaround for 828024 was missing!
        WARNING: BL31: cortex_a57: errata workaround for 829520 was missing!
        WARNING: BL31: cortex_a57: errata workaround for 833471 was missing!
        ...
        VERBOSE: BL31: cortex_a53: errata workaround for 826319 was not applied
        INFO:    BL31: cortex_a53: errata workaround for disable_non_temporal_hint was applied
      
      Also update documentation.
      
      Change-Id: Iccf059d3348adb876ca121cdf5207bdbbacf2aba
      Signed-off-by: default avatarJeenu Viswambharan <jeenu.viswambharan@arm.com>
      10bcd761
  11. 26 Jan, 2017 1 commit
  12. 20 Dec, 2016 1 commit
    • Sandrine Bailleux's avatar
      Improve FWU documentation · 34ba298e
      Sandrine Bailleux authored
      
      
       - Clarify the documentation of the 'FWU_SMC_IMAGE_COPY' SMC in the
         Firmware Update guide. Also extend the list of pre-conditions to
         include the additional input validation implemented by previous
         patches.
      
       - Improve documentation of bl1_plat_mem_check() in the porting
         guide. It now specifies that the generic FWU code protects
         bl1_plat_mem_check() from integer overflows resulting from
         the addition of the base address and size passed in arguments.
      
      Change-Id: I07b47a3778df7b9c089529b2dd2135707640a91c
      Signed-off-by: default avatarSandrine Bailleux <sandrine.bailleux@arm.com>
      34ba298e
  13. 15 Dec, 2016 3 commits
    • David Cunado's avatar
      Update Foundation Model version · 8434f76f
      David Cunado authored
      
      
      Foundation Model release 10.2 has been made available and Trusted
      Firmware has been tested against that it as part of its CI system.
      
      This patch updates the user guide documentation to reflect the version
      of Foundation Model that Trusted Firmware has been tested against.
      
      Change-Id: I8571e1027b24892b41d04b93b24245a371ca2cae
      Signed-off-by: default avatarDavid Cunado <david.cunado@arm.com>
      8434f76f
    • Jeenu Viswambharan's avatar
      Add provision to extend CPU operations at more levels · 5dd9dbb5
      Jeenu Viswambharan authored
      
      
      Various CPU drivers in ARM Trusted Firmware register functions to handle
      power-down operations. At present, separate functions are registered to
      power down individual cores and clusters.
      
      This scheme operates on the basis of core and cluster, and doesn't cater
      for extending the hierarchy for power-down operations. For example,
      future CPUs might support multiple threads which might need powering
      down individually.
      
      This patch therefore reworks the CPU operations framework to allow for
      registering power down handlers on specific level basis. Henceforth:
      
        - Generic code invokes CPU power down operations by the level
          required.
      
        - CPU drivers explicitly mention CPU_NO_RESET_FUNC when the CPU has no
          reset function.
      
        - CPU drivers register power down handlers as a list: a mandatory
          handler for level 0, and optional handlers for higher levels.
      
      All existing CPU drivers are adapted to the new CPU operations framework
      without needing any functional changes within.
      
      Also update firmware design guide.
      
      Change-Id: I1826842d37a9e60a9e85fdcee7b4b8f6bc1ad043
      Signed-off-by: default avatarJeenu Viswambharan <jeenu.viswambharan@arm.com>
      5dd9dbb5
    • dp-arm's avatar
      tbbr: Fix updating of Non-Trusted NV counter · d35dee23
      dp-arm authored
      
      
      The previous code required that a certificate be signed with the ROT
      key before the platform's NV counter could be updated with the value
      in the certificate.  This implies that the Non-Trusted NV counter was
      not being updated for Non-Trusted content certificates, as they cannot
      be signed with the ROT key in the TBBR CoT scheme.
      
      The code is reworked to only allow updating the platform's Trusted NV
      counter when a certificate protected by the Trusted NV counter is
      signed with the ROT key.
      
      Content certificates protected by the Non-Trusted NV counter are
      allowed to update the platform's Non-Trusted NV counter, assuming
      that the certificate value is higher than the platform's value.
      
      A new optional platform API has been introduced, named
      plat_set_nv_ctr2().  Platforms may choose to implement it and perform
      additional checks based on the authentication image descriptor before
      modifying the NV counters.  A default weak implementation is available
      that just calls into plat_set_nv_ctr().
      
      Fixes ARM-software/tf-issues#426
      
      Change-Id: I4fc978fd28a3007bc0cef972ff1f69ad0413b79c
      Signed-off-by: default avatardp-arm <dimitris.papastamos@arm.com>
      d35dee23
  14. 13 Dec, 2016 2 commits
    • Antonio Nino Diaz's avatar
      Add PLAT_xxx_ADDR_SPACE_SIZE definitions · 0029624f
      Antonio Nino Diaz authored
      
      
      Added the definitions `PLAT_PHY_ADDR_SPACE_SIZE` and
      `PLAT_VIRT_ADDR_SPACE_SIZE` which specify respectively the physical
      and virtual address space size a platform can use.
      
      `ADDR_SPACE_SIZE` is now deprecated. To maintain compatibility, if any
      of the previous defines aren't present, the value of `ADDR_SPACE_SIZE`
      will be used instead.
      
      For AArch64, register ID_AA64MMFR0_EL1 is checked to calculate the
      max PA supported by the hardware and to verify that the previously
      mentioned definition is valid. For AArch32, a 40 bit physical
      address space is considered.
      
      Added asserts to check for overflows.
      
      Porting guide updated.
      
      Change-Id: Ie8ce1da5967993f0c94dbd4eb9841fc03d5ef8d6
      Signed-off-by: default avatarAntonio Nino Diaz <antonio.ninodiaz@arm.com>
      0029624f
    • Jeenu Viswambharan's avatar
      Docs: Fix monospace formatting in user guide · adefa3d8
      Jeenu Viswambharan authored
      
      
      Change-Id: I28b2790ff2f87b9fe3cf1020e59e1e0a00be6f97
      Signed-off-by: default avatarJeenu Viswambharan <jeenu.viswambharan@arm.com>
      adefa3d8
  15. 22 Nov, 2016 1 commit
  16. 17 Nov, 2016 1 commit
    • Douglas Raillard's avatar
      Docs: Clarify IRQ/FIQ handler API in Interrupt Design Guide · 94a8ca24
      Douglas Raillard authored
      
      
      The API description currently states that interrupt handlers
      (interrupt_type_handler_t pointers) SHOULD return a pointer
      to the target cpu_context.
      
      This patch rewords the description of the interrupts handlers to state
      that it MUST return a pointer to the target security context. It also
      warns about potential portability issue. Specifically, this pointer is
      not used on AArch64 and calls to context library APIs must be used to
      ask BL31 to return to a specific context. However, this could change in
      the future and interrupt handlers must always return the pointer.
      
      Change-Id: I3f82a046de4d7a5b51a8cbebe7eb2a00dbbdb4f0
      Signed-off-by: default avatarDouglas Raillard <douglas.raillard@arm.com>
      94a8ca24
  17. 14 Nov, 2016 2 commits
  18. 08 Nov, 2016 2 commits
  19. 03 Nov, 2016 2 commits
  20. 24 Oct, 2016 1 commit
  21. 13 Oct, 2016 2 commits
  22. 12 Oct, 2016 2 commits
    • dp-arm's avatar
      PMF: Add documentation · 514a94c2
      dp-arm authored
      
      
      Add a Performance Measurement Framework (PMF) section
      to the firmware design document.
      
      Change-Id: I5953bd3b1067501f190164c8827d2b0d8022fc0b
      Signed-off-by: default avatardp-arm <dimitris.papastamos@arm.com>
      514a94c2
    • Antonio Nino Diaz's avatar
      Fix documentation of bootwrapper boot on juno · 7486eb04
      Antonio Nino Diaz authored
      
      
      The user guide incorrectly claimed that it is possible to load a
      bootwrapped kernel over JTAG on Juno in the same manner as an EL3
      payload. In the EL3 payload boot flow, some of the platform
      initialisations in BL2 are modified. In particular, the TZC settings
      are modified to allow unrestricted access to DRAM. This in turn allows
      the debugger to access the DRAM and therefore to load the image there.
      
      In the BL33-preloaded boot flow though, BL2 uses the default TZC
      programming, which prevent access to most of the DRAM from secure state.
      When execution reaches the SPIN_ON_BL1_EXIT loop, the MMU is disabled
      and thus DS-5 presumably issues secure access transactions while trying
      to load the image, which fails.
      
      One way around it is to stop execution at the end of BL2 instead. At
      this point, the MMU is still enabled and the DRAM is mapped as
      non-secure memory. Therefore, the debugger is allowed to access this
      memory in this context and to sucessfully load the bootwrapped kernel in
      DRAM. The user guide is updated to suggest this alternative method.
      Co-Authored-By: default avatarSandrine Bailleux <sandrine.bailleux@arm.com>
      Signed-off-by: default avatarDan Handley <dan.handley@arm.com>
      
      Change-Id: I537ea1c6d2f96edc06bc3f512e770c748bcabe94
      7486eb04
  23. 11 Oct, 2016 3 commits
    • Soby Mathew's avatar
      AArch32: Update user-guide and add DTBs · 5e21d795
      Soby Mathew authored
      This patch adds necessary updates for building and running Trusted
      Firmware for AArch32 to user-guide.md. The instructions for running
      on both `FVP_Base_AEMv8A-AEMv8A` in AArch32 mode and
      `FVP_Base_Cortex-A32x4` models are added. The device tree files for
      AArch32 Linux kernel are also added in the `fdts` folder.
      
      Change-Id: I0023b6b03e05f32637cb5765fdeda8c8df2d0d3e
      5e21d795
    • Yatharth Kochar's avatar
      AArch32: Update firmware-design.md · 9a3236ea
      Yatharth Kochar authored
      This patch updates the firmware-design.md for AArch32 related changes.
      
      Change-Id: Idf392a44861ab9c1f59f3de4f3435f508b17c678
      9a3236ea
    • Jeenu Viswambharan's avatar
      Docs: Rename duplicate title in porting guide · ec2653a7
      Jeenu Viswambharan authored
      Fix one of the two titles that ended up being the same, although both
      describe different things.
      
      Change-Id: I66ecf369643709898ee4c014659d8f85c0480643
      ec2653a7
  24. 28 Sep, 2016 1 commit
    • Soby Mathew's avatar
      Docs: Add the PSCI library integration guide · 9e534b20
      Soby Mathew authored
      This patch adds the PSCI library integration guide for AArch32 ARMv8-A
      systems `psci-lib-integration-guide.md` to the documentation. The
      patch also adds appropriate reference to the new document in
      the `firmware-design.md` document.
      
      Change-Id: I2d5b5c6b612452371713399702e318e3c73a8ee0
      9e534b20
  25. 27 Sep, 2016 1 commit
    • Sandrine Bailleux's avatar
      Upgrade Linaro release, FVPs and mbed TLS versions · 605a4fc7
      Sandrine Bailleux authored
      This patch updates the User Guide to recommend the latest version
      of some of the software dependencies of ARM Trusted Firmware.
      
       - Upgrade Linaro release:     16.02 -> 16.06
      
       - Upgrade FVPs
          - Foundation v8 FVP:       9.5 -> 10.1
          - Base FVPs:               7.6 -> 7.7
      
       - Upgrade mbed TLS library:   2.2.0 -> 2.2.1
      
      Note that the latest release of mbed TLS as of today is 2.3.0 but it has
      compilations issues with the set of library configuration options that
      Trusted Firmware uses. 2.2.1 is the next most recent release known to
      build with TF.
      
      This patch also fixes the markdown formatting of a link in the
      User Guide.
      
      Change-Id: Ieb7dd336f4d3110fba060afec4ad580ae707a8f1
      605a4fc7
  26. 21 Sep, 2016 1 commit
    • Yatharth Kochar's avatar
      AArch32: Common changes needed for BL1/BL2 · 1a0a3f06
      Yatharth Kochar authored
      This patch adds common changes to support AArch32 state in
      BL1 and BL2. Following are the changes:
      
      * Added functions for disabling MMU from Secure state.
      * Added AArch32 specific SMC function.
      * Added semihosting support.
      * Added reporting of unhandled exceptions.
      * Added uniprocessor stack support.
      * Added `el3_entrypoint_common` macro that can be
        shared by BL1 and BL32 (SP_MIN) BL stages. The
        `el3_entrypoint_common` is similar to the AArch64
        counterpart with the main difference in the assembly
        instructions and the registers that are relevant to
        AArch32 execution state.
      * Enabled `LOAD_IMAGE_V2` flag in Makefile for
        `ARCH=aarch32` and added check to make sure that
        platform has not overridden to disable it.
      
      Change-Id: I33c6d8dfefb2e5d142fdfd06a0f4a7332962e1a3
      1a0a3f06