diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 7dbb4fdd..d9b3e326 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -145,8 +145,27 @@ jobs:
       - name: Perform CodeQL Analysis
         uses: github/codeql-action/analyze@v3
 
-  manylinux:
+  riscv64:
+    runs-on: ubuntu-latest
+    name: RiscV 64
+    steps:
+      - name: checkout
+        uses: actions/checkout@v4
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.13"
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v3
+        with:
+          platforms: all
+      - name: Build and test greenlet
+        env:
+          DOCKER_IMAGE: riscv64/ubuntu:latest
+        run: bash ./ubuntu-test
 
+
+  manylinux:
     runs-on: ubuntu-latest
     # We use a regular Python matrix entry to share as much code as possible.
     strategy:
diff --git a/MANIFEST.in b/MANIFEST.in
index f9b94e87..3c0c8ccf 100644
--- a/MANIFEST.in
+++ b/MANIFEST.in
@@ -50,6 +50,7 @@ include LICENSE.PSF
 include MANIFEST.in
 
 include make-manylinux
+include ubuntu-test
 
 global-exclude *.pyc
 global-exclude *.pyd
diff --git a/src/greenlet/platform/switch_riscv_unix.h b/src/greenlet/platform/switch_riscv_unix.h
index 32ca78c8..87611222 100644
--- a/src/greenlet/platform/switch_riscv_unix.h
+++ b/src/greenlet/platform/switch_riscv_unix.h
@@ -12,13 +12,9 @@ static int
 slp_switch(void)
 {
   int ret;
-#if __riscv_xlen == 32
   long fp;
   long *stackref, stsizediff;
-#else
-  int fp;
-  int *stackref, stsizediff;
-#endif
+
   __asm__ volatile ("" : : : REGS_TO_SAVE);
   __asm__ volatile ("mv %0, fp" : "=r" (fp) : );
   __asm__ volatile ("mv %0, sp" : "=r" (stackref) : );
diff --git a/ubuntu-test b/ubuntu-test
new file mode 100755
index 00000000..93854348
--- /dev/null
+++ b/ubuntu-test
@@ -0,0 +1,47 @@
+#!/bin/bash
+
+# This needs to be run from the root of the project.
+
+set -e
+export PYTHONUNBUFFERED=1
+export PYTHONDONTWRITEBYTECODE=1
+# Use a fixed hash seed for reproducibility
+export PYTHONHASHSEED=8675309
+export CI=1
+export TRAVIS=true
+export PIP_NO_WARN_SCRIPT_LOCATION=1
+
+
+if [ -d /greenlet ]; then
+    # Running inside docker
+    export GREENLET_MANYLINUX=1
+    # Our setup.py overrides this with -Os; be sure it does.
+    export CFLAGS="-O3 -DNDEBUG -Wall"
+
+    apt-get update
+    apt-get install -y python3.12 python3.12-dev python3.12-venv gcc git g++
+    update-alternatives --install /usr/bin/python python /usr/bin/python3.12 1
+
+    # Build in an isolated directory
+    mkdir /tmp/build
+    cd /tmp/build
+    git config --global --add safe.directory /greenlet/.git
+    git clone /greenlet greenlet
+    cd greenlet
+
+    python -m venv /tmp/venv
+    . /tmp/venv/bin/activate
+    echo "Python"
+    python --version
+
+    python -mpip install -U pip
+    python -mpip install -U setuptools wheel
+    python -mpip wheel -v --wheel-dir ./dist .
+    python -mpip install -U .[test]
+    python -m unittest discover -v greenlet.tests
+
+    exit 0
+fi
+
+# Mount the current directory as /greenlet
+docker run --rm --platform linux/riscv64 -v "$(pwd):/greenlet"  ${DOCKER_IMAGE:-riscv64/ubuntu:latest} /greenlet/$(basename $0)