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RISC-V Crypto Tools

Instructions and notes on building an experimental RISC-V Crypto enabled toolchain and ISA simulator.

NOTE: There is a task-list for creating an official GCC/Binutils patch for the scalar cryptography extension here.

Building the Toolchain

TL;DR:

$> export RISCV_ARCH=riscv64-unknown-elf
$> source bin/conf.sh
$> $REPO_HOME/tools/start-from-scratch.sh

You only need to clone the external repos once.

Long Version:

After first checking out the riscv-crypto repository:

  • From the root of the project, run:

    source bin/conf.sh

    to setup the project workspace.

    • Note the value RISCV, This describes where the toolchain will be installed too.

  • Checkout the relevant repositories:

    ${REPO_HOME}/tools/clone.sh

    This will clone GCC, Binutils, Newlib, the RISC-V Proxy kernel (PK) and the RISC-V ISA Simulator (Spike).

    It will then checkout known good commits on a new branch called riscv-crypto.

  • For each component in the tool-chain, execute the associated patch application, configuration, and compilation (plus installation) script in turn:

    • gcc/binutils

      ${REPO_HOME}/tools/toolchain-conf.sh
${REPO_HOME}/tools/toolchain-build.sh

    • pk (the RISC-V proxy kernel):

      ${REPO_HOME}/tools/pk-apply.sh
${REPO_HOME}/tools/pk-conf.sh
${REPO_HOME}/tools/pk-build.sh

    • spike:

      ${REPO_HOME}/tools/spike-apply.sh
${REPO_HOME}/tools/spike-conf.sh
${REPO_HOME}/tools/spike-build.sh

    • This will build binutils, gcc, pk and spike, and place the compiled results in ${REPO_HOME}/build/toolchain/install.

    • You can go and make some tea / coffee for this bit, it will take a while.

    • The architecture the compiler will target is specified in ${REPO_HOME}/tools/share.sh as TARGET_ARCH, ARCH_STRINGandABI_STRING`.

  • To re-build a repository from scratch, first run the relevant ${REPO_HOME}/tools/conf-*.sh script before running the corresponding build script.

Development flow

This section describes the development flow for the riscv-crypto toolchain and simulator patches.

  • Assuming a fresh checkout of the riscv-crypto repository, run the Getting Started steps described above so that you have a working baseline toolchain installation.

    • Running these steps will apply the patches to binutils, gcc and spike from the corresponding tools/patch-*.patch file.

  • There are three classes of tool script used to manage the patches:

    • The tools/*-apply.sh scripts are used to take the patches contained in the RISC-V Crypto repository and apply them to the cloned upstream repositories.

    • The tools/*-revert.sh scripts are used to put the cloned upstream repositories back to their known initial state.

    • The tools/*-update.sh scripts take the staged modifications to the relevant repository and updates the RISC-V Crypto diff.

  • To modify a patch:

    • When the upstream repositores are first cloned, all relevant patches are automatically applied.

    • If a change is made to a cloned repository, you must run git add to make sure the changes are staged for commit. Do Not commit your changes to the cloned repository.

    • Then, run the appropriate tools/*-update.sh script and commit the change to the patch to the RISC-V Crypto repository.

Relevant Files

These are the relevant files / locations which need editing when adding or changing instructions.

Binutils

  • See extern/riscv-gnu-toolchain/riscv-binutils.
  • gas/config/tc-riscv.c - Instruction assembly.
  • include/opcode/riscv-opc.h - Instruction encoding masks.
  • include/opcode/riscv.h - Instruction field masks.
  • opcodes/riscv-dis.c - Disassembly.
  • opcodes/riscv-opc.c - Instruction mnemonic and argument lists.

Spike

  • See extern/riscv-isa-sim.
  • riscv/decode.h - Instruction encoding field access.
  • riscv/encoding.h - Instruction encoding masks.
  • riscv/riscv.mk.in - Makefile listing included instructions.
  • riscv/insns/* - Instruction implementatons.