Streamline installation process.

* README.md (Prerequisites): Update.
* verif/regress/install-cva6.sh (CV_SW_PREFIX): Add comment on value auto-
  detection.
  (RISCV_GCC): Ditto.
  (RISCV_OBJCOPY): Ditto.
  (SPIKE_ROOT): Replace with SPIKE_INSTALL_DIR.
* verif/regress/install-riscv-dv.sh (SPIKE_ROOT): Ditto.
* verif/regress/install-spike.sh (ROOT_PROJECT): Set automatically from
  script path at all times.
  (SPIKE_ROOT): Phase out.
  (build+install procedure): Update log messages.
* verif/sim/cva6.py (main): Replace SPIKE_ROOT with SPIKE_INSTALL_DIR.

README.md

@@ -129,18 +129,44 @@ This BSP is used by both `core` testbench and `uvmt_cva6` UVM verification envir
 There are README files in each directory with additional information.
 
 #### Prerequisites
-To execute tests on CVA6 core, you need a RISC-V toolchain.
 
-To build and install RISC-V GCC compiler locally, you can use the toolchain generation scripts
-located under `util/gcc-toolchain-builder`.
+In brief, you will need:
+- a native C/C++ development environment to build simulation tools and models;
+- a RISC-V toolchain to build the CVA6 test programs;
+- optionally, an EDA tool that supports building and running simulation models of designs expressed in SystemVerilog.
+
+To build the open-source tools used by CVA6 and to run CVA6 simulations, you will need
+a native compilation toolchain for C and C++.  Such toolchains are available on virtually
+all Linux distributions as pre-installed or optional packages.   If unsure, ask your system
+administrator to install one on your system.
+
+To build test programs for the CVA6 core, you need a RISC-V toolchain.
+For GCC-based toolchains, only GCC versions above 11.1.0 are supported;
+it is recommended to use GCC 13.1.0 or above.
+
+You can use a pre-built toolchain (available for most common Linux/macOS
+distributions from a variety of providers) or build one from scratch using
+publicly available source code repositiores.  The second approach may prove
+necessary on older or unsupported Linux installations.
+
+To use a pre-built RISC-V toolchain, download and install the package(s) for your
+Linux distribution as per instructions from the toolchain provider, and set the
+`RISCV` environment variable to the installation location of the toolchain:
+
+```sh
+# Set environment variable RISCV to the location of the installed toolchain.
+export RISCV=/path/to/toolchain/installation/directory
+```
+
+To build and install RISC-V GCC toolchain locally, you can use the toolchain generation scripts
+located under `util/gcc-toolchain-builder`.  Please make sure beforehand that you have
+installed all the required *toolchain build* dependencies (see
+[the toolchain README file](file:util/gcc-toolchain-builder/README.md).)
 
 ```sh
-# Set environment variables. The toolchain can be installed
-# in any user-writable directory.
+# Set environment variable RISCV to the desired installation location.
+# The toolchain can be installed in any user-writable directory.
 export RISCV=/path/to/toolchain/installation/directory
-export CV_SW_PREFIX=riscv-none-elf-
-export RISCV_PREFIX=$RISCV/bin/$CW_SW_PREFIX
-export RISCV_GCC=$RISCV_PREFIXgcc
 
 # Get the source code of toolchain components from public repositiories.
 cd util/gcc-toolchain-builder
@@ -155,8 +181,7 @@ bash ./build-toolchain.sh $RISCV
 cd -
 ```
 
-These four variables will ensure you use correctly the new gcc compiler you have just installed.
-You will now be able to run the test scripts.
+You will now be able to run the CVA6 test scripts.
 
 #### Environent setup
 

verif/regress/install-cva6.sh

@@ -17,14 +17,17 @@ if [ -z "$RISCV" ]; then
   return
 fi
 
+# Auto-detect RISC-V tool name prefix if not explicitly given.
 if [ -z "$CV_SW_PREFIX" ]; then
     export CV_SW_PREFIX="$(ls -1 -r $RISCV/bin/riscv*-gcc | head -n 1| grep gcc | rev | cut -d '/' -f 1 | cut -d '-' -f 2- | rev)-"
 fi
 
+# Default to auto-detected GCC name if not explicitly given.
 if [ -z "$RISCV_GCC" ]; then
     export RISCV_GCC=$RISCV/bin/${CV_SW_PREFIX}gcc
 fi
 
+# Default to auto-detected OBJCOPY name if not explicitly given.
 if [ -z "$RISCV_OBJCOPY" ]; then
     export RISCV_OBJCOPY=$RISCV/bin/${CV_SW_PREFIX}objcopy
 fi
@@ -76,7 +79,7 @@ echo $CVA6_HASH
 echo $CVA6_PATCH
 
 # install Spike
-if [ -z "$SPIKE_ROOT" ]; then
-  export SPIKE_ROOT=$TOP/spike/
+if [ -z "$SPIKE_INSTALL_DIR" ]; then
+  export SPIKE_INSTALL_DIR=$TOP/spike/
 fi
 source verif/regress/install-spike.sh

verif/regress/install-riscv-dv.sh

@@ -15,7 +15,7 @@ fi
 if [ -z "$RISCV_OBJCOPY" ]; then
   export RISCV_OBJCOPY="$RISCV_TOOLCHAIN/bin/riscv-none-elf-objcopy"
 fi
-export SPIKE_PATH=$SPIKE_ROOT/bin
+export SPIKE_PATH=$SPIKE_INSTALL_DIR/bin
 export RTL_PATH=$ROOT_PROJECT/
 export TB_PATH=$ROOT_PROJECT/verif/tb/core
 export TESTS_PATH=$ROOT_PROJECT/verif/tests

verif/regress/install-spike.sh

@@ -11,6 +11,9 @@ if [ -z ${NUM_JOBS} ]; then
     NUM_JOBS=1
 fi
 
+# Get the path to the top of the CVA6 installation.  Assume we are located in CVA6_TOP/verif/regress.
+ROOT_PROJECT=$(readlink -f $(dirname $0))/../..
+
 # Set SPIKE_INSTALL_DIR to 'NO' to skip the installation/checks of Spike
 # altogether.
 # This is useful for CI jobs not depending on Spike in any way.
@@ -24,8 +27,7 @@ fi
 if [ "$SPIKE_INSTALL_DIR" = "NO" ]; then
   echo "NOTE: Skipping Spike setup on user's request (\$SPIKE_INSTALL_DIR = \"NO\")."
 else
-  # Export the location of Spike source code.  Assume we are located in CVA6_TOP/verif/regress.
-  ROOT_PROJECT=$(readlink -f $(dirname $0))/../..
+  # Export the location of Spike source code.
   export SPIKE_SRC_DIR=$ROOT_PROJECT/vendor/riscv/riscv-isa-sim
 
   # Check if a local copy of Spike should be built/used ($SPIKE_INSTALL_DIR non empty).
@@ -35,29 +37,26 @@ else
       if [ "$SPIKE_INSTALL_DIR" = "__local__" ]; then
         export SPIKE_INSTALL_DIR="$ROOT_PROJECT/tools/spike"
       fi
-      # Override SPIKE_ROOT value with $SPIKE_INSTALL_DIR (the latter takes priority.)
-      # TODO: Remove the following two lines when SPIKE_ROOT is phased out.
-      echo "NOTE: Overriding SPIKE_ROOT value ('$SPIKE_ROOT') with \$SPIKE_INSTALL_DIR ('$SPIKE_INSTALL_DIR')."
-      export SPIKE_ROOT="$SPIKE_INSTALL_DIR"
       # Do not clean up the destination directory: leave that to the user (real or CI job).
   fi
 
   # Rebuild Spike or reuse an existing Spike build.
   if [ ! -d "$SPIKE_INSTALL_DIR" -o ! -f "$SPIKE_INSTALL_DIR/bin/spike" ]; then
-    echo "Installing Spike in '$SPIKE_INSTALL_DIR'..."
     # Keep track of current working dir.
     CALLER_DIR=$(readlink -f $(pwd))
     # Enter the vendorized tree.  It already captures the desired Spike config.
     cd $SPIKE_SRC_DIR
+    echo "Building Spike sources in $SPIKE_SRC_DIR..."
     # Build and install Spike (including extensions).
     mkdir -p build
     cd build
-    ../configure --enable-commitlog --prefix="$SPIKE_INSTALL_DIR"
+    ../configure --prefix="$SPIKE_INSTALL_DIR"
     make -j${NUM_JOBS}
+    echo "Installing Spike in '$SPIKE_INSTALL_DIR'..."
     make install
     cd $CALLER_DIR
   else
-    echo "Using Spike from cached directory '$SPIKE_INSTALL_DIR'."
+    echo "Using pre-installed Spike from '$SPIKE_INSTALL_DIR'."
   fi
 fi
 

verif/sim/cva6.py

@@ -1001,7 +1001,7 @@ def main():
       sys.exit(RET_FAIL)
     #print environment softwares
     logging.info("GCC Version : %s" % (gcc_version))
-    spike_version=get_env_var("SPIKE_ROOT")
+    spike_version=get_env_var("SPIKE_INSTALL_DIR")
     logging.info("Spike Version : %s" % (spike_version))
     verilator_version=run_cmd("verilator --version")
     logging.info("Verilator Version : %s" % (verilator_version))