Add Docker container to host caliptra build tools (#2372)

This will be used particularly in caliptra-mcu-sw as well as local
cross-compilation. Eventually we will
want to separate this to an infra specific repo.

Author: clundin25

.github/workflows/publish-build-image.yml

@@ -0,0 +1,38 @@
+name: Publish Docker Build Image
+
+on:
+  push:
+    branches:
+      - main
+    paths:
+      - 'ci-tools/build-image/Dockerfile'
+  workflow_dispatch:
+
+jobs:
+  # Publishes "ghcr.io/chipsalliance/caliptra-build-image".
+  build-and-publish:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: write
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Log in to the GitHub Container Registry
+        uses: docker/login-action@v3
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Build and push Docker image
+        uses: docker/build-push-action@v5
+        with:
+          context: ci-tools/build-image
+          file: ci-tools/build-image/Dockerfile
+          push: true
+          tags: |
+            ghcr.io/${{ github.repository_owner }}/caliptra-build-image:latest
+            ghcr.io/${{ github.repository_owner }}/caliptra-build-image:${{ github.sha }}

ci-tools/build-image/Dockerfile

@@ -0,0 +1,16 @@
+# Licensed under the Apache-2.0 license
+
+# This docker image shares a rootfs with the Caliptra FPGAs.
+# This image is used in various GitHub actions to cross-compile binaries targeting the FPGAs.
+
+# Move dev images to debian.
+#FROM debian:bookworm
+FROM ubuntu:22.04
+RUN apt update && apt install gcc git curl make gcc-aarch64-linux-gnu  -y
+RUN curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- --default-toolchain=nightly-2025-02-15 --profile=complete -y
+ENV PATH="/root/.cargo/bin:${PATH}"
+RUN rustup target add riscv32imc-unknown-none-elf 
+RUN rustup target add aarch64-unknown-linux-gnu
+RUN cargo install cargo-nextest
+ENV CARGO_TARGET_AARCH64_UNKNOWN_LINUX_GNU_LINKER="aarch64-linux-gnu-gcc"
+