CI: Add support for ppc64le

For now only using clang.

Adds -vga none to the qemu command for all targets. But AFAICS that's
safe as both x86 and arm use serial consoles already.

Uses RUST_OPT_LEVEL_SIMILAR_AS_CHOSEN_FOR_C, not RUST_OPT_LEVEL_0 like
other configs. In order to avoid crashes like:

  Rust Example (init)
  Am I built-in? true
  Parameters:
    my_bool:    true
    my_i32:     123321
    my_str:     🦀mod
    my_usize:   42
    my_array:   [0, 1]
  Value: 10
  Value: 10
  Large array has length: 514
  Kernel panic - not syncing: corrupted stack end detected inside scheduler
  CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.12.0-rc3+ #1

Signed-off-by: Michael Ellerman <[email protected]>

Author: mpe

.github/workflows/ci.yaml

@@ -48,6 +48,14 @@ jobs:
             install: standalone
             sysroot: custom
 
+          - arch: ppc64le
+            toolchain: clang
+            config: debug
+            rustc: 2021-02-20
+            output: src
+            install: rustup
+            sysroot: common
+
     steps:
       # Setup: checkout
       - uses: actions/checkout@v2
@@ -68,6 +76,14 @@ jobs:
           echo 'QEMU_ARCH=aarch64' >> $GITHUB_ENV
           echo 'QEMU_MACHINE=virt' >> $GITHUB_ENV
           echo 'QEMU_CPU=cortex-a72' >> $GITHUB_ENV
+      - if: matrix.arch == 'ppc64le'
+        run: |
+          echo 'MAKE_ARCH=ARCH=powerpc' >> $GITHUB_ENV
+          echo 'MAKE_CROSS_COMPILE=CROSS_COMPILE=powerpc64le-linux-gnu-' >> $GITHUB_ENV
+          echo 'IMAGE_PATH=vmlinux' >> $GITHUB_ENV
+          echo 'QEMU_ARCH=ppc64' >> $GITHUB_ENV
+          echo 'QEMU_MACHINE=pseries' >> $GITHUB_ENV
+          echo 'QEMU_CPU=POWER9' >> $GITHUB_ENV
 
       - if: matrix.toolchain == 'clang'
         run: echo 'MAKE_TOOLCHAIN=CC=clang-11' >> $GITHUB_ENV
@@ -94,6 +110,8 @@ jobs:
       # Setup: GCC
       - if: matrix.arch == 'arm64'
         run: sudo apt-get install -y gcc-aarch64-linux-gnu
+      - if: matrix.arch == 'ppc64le'
+        run: sudo apt-get install -y gcc-powerpc64le-linux-gnu
 
       # Setup: libelf
       - run: sudo apt-get install -y libelf-dev
@@ -103,6 +121,8 @@ jobs:
         run: sudo apt-get install -y qemu-system-x86
       - if: matrix.arch == 'arm64'
         run: sudo apt-get install -y qemu-system-arm
+      - if: matrix.arch == 'ppc64le'
+        run: sudo apt-get install -y qemu-system-ppc64
 
       # Setup: rustc
       - if: matrix.install == 'rustup'
@@ -164,6 +184,7 @@ jobs:
             -cpu ${{ env.QEMU_CPU }} \
             -smp 2 \
             -nographic \
+            -vga none \
             -no-reboot \
             -append '${{ env.QEMU_APPEND }} \
               rust_example.my_i32=123321 \