Merge "Fix the CAS spinlock implementation" into integration

diff --combined docs/getting_started/user-guide.rst
index 6dad31058e37b198c6859fa012971ae71ef176cf,ae276f25dcaf48886348df7e978e0286829fe121..e540fd06aec0d9ed00eb3faf46540c4b0f6b5e04
--- 1/docs/getting_started/user-guide.rst
--- 2/docs/getting_started/user-guide.rst
+++ b/docs/getting_started/user-guide.rst
@@@ -9,7 -9,7 +9,7 @@@ is outside the scope of this document
  
  This document assumes that the reader has previous experience running a fully
  bootable Linux software stack on Juno or FVP using the prebuilt binaries and
 -filesystems provided by `Linaro`_. Further information may be found in the
 +filesystems provided by Linaro. Further information may be found in the
  `Linaro instructions`_. It also assumes that the user understands the role of
  the different software components required to boot a Linux system:
  
@@@ -48,8 -48,15 +48,8 @@@ Install the required packages to build 
  
      sudo apt-get install device-tree-compiler build-essential gcc make git libssl-dev
  
 -TF-A has been tested with Linaro Release 18.04.
 -
  Download and install the AArch32 (arm-eabi) or AArch64 little-endian
 -(aarch64-linux-gnu) GCC cross compiler. If you would like to use the latest
 -features available, download GCC 8.3-2019.03 compiler from
 -`arm Developer page`_. Otherwise, the `Linaro Release Notes`_ documents which
 -version of the compiler to use for a given Linaro Release. Also, these
 -`Linaro instructions`_ provide further guidance and a script, which can be used
 -to download Linaro deliverables automatically.
 +(aarch64-linux-gnu) GCC 8.3-2019.03 cross compiler from `Arm Developer page`_.
  
  Optionally, TF-A can be built using clang version 4.0 or newer or Arm
  Compiler 6. See instructions below on how to switch the default compiler.
@@@ -66,10 -73,6 +66,10 @@@ In addition, the following optional pac
     This tool can be found in most Linux distributions. Inkscape is needed to
     generate the actual \*.png files.
  
 +TF-A has been tested with pre-built binaries and file systems from
 +`Linaro Release 19.06`_. Alternatively, you can build the binaries from
 +source using instructions provided at the `Arm Platforms User guide`_.
 +
  Getting the TF-A source code
  ----------------------------
  
@@@ -124,7 -127,7 +124,7 @@@ Building TF-
  -------------
  
  -  Before building TF-A, the environment variable ``CROSS_COMPILE`` must point
 -   to the Linaro cross compiler.
 +   to the cross compiler.
  
     For AArch64:
  
@@@ -817,6 -820,10 +817,10 @@@ Common build option
     reduces SRAM usage. Refer to `Library at ROM`_ for further details. Default
     is 0.
  
+ -  ``USE_SPINLOCK_CAS``: Setting this build flag to 1 selects the spinlock
+     implementation variant using the ARMv8.1-LSE compare-and-swap instruction.
+     Notice this option is experimental and only available to AArch64 builds.
+ 
  -  ``V``: Verbose build. If assigned anything other than 0, the build commands
     are printed. Default is 0.
  
@@@ -1398,7 -1405,7 +1402,7 @@@ a single FIP binary. It assumes that a 
     separately for AArch32.
  
     -  Before building BL32, the environment variable ``CROSS_COMPILE`` must point
 -      to the AArch32 Linaro cross compiler.
 +      to the AArch32 cross compiler.
  
        .. code:: shell
  
@@@ -1419,7 -1426,7 +1423,7 @@@
            make realclean
  
     -  Before building BL1 and BL2, the environment variable ``CROSS_COMPILE``
 -      must point to the AArch64 Linaro cross compiler.
 +      must point to the AArch64 cross compiler.
  
        .. code:: shell
  
@@@ -2151,9 -2158,11 +2155,9 @@@ Running the software on Jun
  
  This version of TF-A has been tested on variants r0, r1 and r2 of Juno.
  
 -To execute the software stack on Juno, the version of the Juno board recovery
 -image indicated in the `Linaro Release Notes`_ must be installed. If you have an
 -earlier version installed or are unsure which version is installed, please
 -re-install the recovery image by following the
 -`Instructions for using Linaro's deliverables on Juno`_.
 +To execute the software stack on Juno, installing the latest Arm Platforms
 +software deliverables is recommended. Please install the deliverables by
 +following the `Instructions for using Linaro's deliverables on Juno`_.
  
  Preparing TF-A images
  ~~~~~~~~~~~~~~~~~~~~~
@@@ -2188,11 -2197,11 +2192,11 @@@ wakeup interrupt from RTC
  
  *Copyright (c) 2013-2019, Arm Limited and Contributors. All rights reserved.*
  
 -.. _arm Developer page: https://developer.arm.com/open-source/gnu-toolchain/gnu-a/downloads
 -.. _Linaro: `Linaro Release Notes`_
 -.. _Linaro Release: `Linaro Release Notes`_
 -.. _Linaro Release Notes: https://community.arm.com/dev-platforms/w/docs/226/old-release-notes
 -.. _Linaro instructions: https://community.arm.com/dev-platforms/w/docs/304/arm-reference-platforms-deliverables
 +.. _Arm Developer page: https://developer.arm.com/open-source/gnu-toolchain/gnu-a/downloads
 +.. _Linaro Release: http://releases.linaro.org/members/arm/platforms
 +.. _Linaro Release 19.06: http://releases.linaro.org/members/arm/platforms/19.06
 +.. _Linaro instructions: https://git.linaro.org/landing-teams/working/arm/arm-reference-platforms.git/about
 +.. _Arm Platforms User guide: https://git.linaro.org/landing-teams/working/arm/arm-reference-platforms.git/about/docs/user-guide.rst
  .. _Instructions for using Linaro's deliverables on Juno: https://community.arm.com/dev-platforms/w/docs/303/juno
  .. _Arm Platforms Portal: https://community.arm.com/dev-platforms/
  .. _Development Studio 5 (DS-5): https://developer.arm.com/products/software-development-tools/ds-5-development-studio