RISC-V HPC Application Porting

Native RISC-V porting of HPC applications from the LFX RISC-V target spreadsheet, performed inside a riscv64/ubuntu:24.04 Docker container on Apple Silicon (M1). All binaries were compiled natively on RISC-V — not cross-compiled from x86.

This repository is the supporting evidence for my LFX Mentorship application proposal:
Broadening the RISC-V High Precision Code Base and Reach

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Ported Applications

#	Application	Category	Build System	Validation
1	LAMMPS	Molecular dynamics	CMake	Binary self-reports riscv64, 500+ source files, zero arch errors
2	HPCC (HPL)	HPC benchmark suite	HPL arch-file	Binary executes, awaits hpccinf.txt config
3	Graph500	Graph benchmark	Makefile + MPI	64 BFS + 64 SSSP iterations validated, ~8.5e+07 TEPS
4	CloverLeaf	Hydrodynamics mini-app	Makefile	Runs, timestep output verified
5	standard-RAxML	Phylogenetics	Makefile	RISC-V ELF binary, exits with standard usage message

Full build logs, error traces, and step-by-step notes for each port are in logs/porting_log.md.

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Error Taxonomy

Across these 5 codebases I identified 11 recurring build-failure classes. These patterns form the basis for my automation script, which maps each class to a detection-and-fix rule.

#	Error Class	Observed In	Fix
1	Hardcoded -march=native	CloverLeaf, common in raw Makefiles	Replace with -march=rv64gc (arch-detect block)
2	Missing core toolchain (Fortran)	CloverLeaf, HPCC	apt install gfortran
3	Missing MPI compiler/runtime	Graph500, HPCC, LAMMPS	apt install libopenmpi-dev openmpi-bin
4	GCC 10+ -fno-common linker failures	Graph500, legacy C projects	Add -fcommon to CFLAGS
5	Env CFLAGS dropping internal includes	Graph500, typical in older Makefiles	Always append flags, never replace
6	Broken or implicit default make targets	Graph500	Build specific target explicitly
7	x86 intrinsics leaking into scalar builds	RAxML, hand-optimized HPC code	#if defined(__x86_64__) guard
8	Hardcoded absolute paths for MPI/BLAS	HPCC	Update MPdir for container layout
9	Hardcoded legacy BLAS (e.g., ATLAS)	HPCC	Swap to OpenBLAS, link -lopenblas
10	Missing build-time script dependencies	LAMMPS	apt install python3 python3-dev
11	QEMU user-mode OOM at high concurrency	LAMMPS, any large CMake build	Throttle to make -j2

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Patches and Configs

These are the only source modifications made. Apply them to a fresh clone of each upstream repo.

CloverLeaf patch patches/cloverleaf-march-riscv.patch

Replaces hardcoded -march=native with an architecture-detecting block:

ARCH := $(shell uname -m)
ifeq ($(ARCH), riscv64)
    ARCH_FLAGS = -march=rv64gc
else
    ARCH_FLAGS = -march=native
endif

Apply:

git clone https://github.com/UK-MAC/CloverLeaf_Serial
cd CloverLeaf_Serial
git apply ../patches/cloverleaf-march-riscv.patch
make COMPILER=GNU

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RAxML patches patches/raxml-x86-intrinsic-guard.patch and patches/raxml-sse_shim.h

Two changes:

1. axml.c: Tightens the preprocessor guard from a PPC-exclusion (which accidentally lets RISC-V through) to an explicit x86-only inclusion. Changes #if !(ppc...) to #if defined(__x86_64__) || defined(__i386__) at the _mm_setcsr call site.

2. sse_shim.h: New file. Provides scalar type aliases for __m128d, __m128, __m128i and no-op macros for _mm_setzero_pd, _mm_load_pd, _mm_store_pd on RISC-V and AArch64. Included in place of <xmmintrin.h>.

Apply:

git clone https://github.com/stamatak/standard-RAxML
cd standard-RAxML
cp ../patches/raxml-sse_shim.h sse_shim.h
git apply ../patches/raxml-x86-intrinsic-guard.patch
make -f Makefile.gcc

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HPCC config configs/hpcc-Make.riscv

Custom HPL platform file for the riscv64 container. Key differences from the stub in the upstream repo:

• MPdir = /usr/lib/riscv64-linux-gnu/openmpi (OpenMPI, not MPICH)
• LAlib = -lopenblas (OpenBLAS, not ATLAS)
• LINKER = /usr/bin/mpicc with -DHPL_CALL_CBLAS (eliminates the g77 Fortran linker dependency)
• CCFLAGS uses -march=rv64gc explicitly

Apply:

git clone https://github.com/icl-utk-edu/hpcc
cd hpcc
cp ../configs/hpcc-Make.riscv hpl/Make.riscv
make arch=riscv

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Graph500 — no patch needed

Only runtime flags and dependency installs required. No source changes:

git clone https://github.com/graph500/graph500
cd graph500/src
apt install -y libopenmpi-dev openmpi-bin
make graph500_reference_bfs_sssp CFLAGS="-g -O2 -DSSSP -fcommon -I../aml"
mpirun --allow-run-as-root -np 1 ./graph500_reference_bfs_sssp 10

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LAMMPS — no patch needed

Only CMake flags and a Python install required. No source changes:

git clone https://github.com/lammps/lammps
cd lammps && mkdir build && cd build
apt install -y python3 python3-dev libopenmpi-dev
cmake ../cmake \
  -DCMAKE_CXX_COMPILER=mpicxx \
  -DCMAKE_CXX_FLAGS='-march=rv64gc' \
  -DBUILD_MPI=yes \
  -C ../cmake/presets/nolib.cmake
make -j2

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Environment

Container:   riscv64/ubuntu:24.04 (Docker + QEMU binfmt on Apple Silicon M1)
Compiler:    GCC 13.3 (native riscv64)
Fortran:     GFortran 13.3
MPI:         OpenMPI 4.1.6 (native riscv64 Debian package)
BLAS:        OpenBLAS (libopenblas-dev:riscv64 — native Debian package)
Build tools: CMake 3.28, GNU Make 4.3, Autotools

To reproduce the environment:

docker run --platform linux/riscv64 -it riscv64/ubuntu:24.04 bash
apt update && apt install -y \
  gcc g++ gfortran make cmake git \
  libopenmpi-dev openmpi-bin \
  libopenblas-dev \
  python3 python3-dev

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Repository Structure

riscv-porting/
   lfx_proposal.md            // LFX mentorship proposal
   patches/
         cloverleaf-march-riscv.patch
         raxml-x86-intrinsic-guard.patch
         raxml-sse_shim.h
   configs/
         hpcc-Make.riscv
   logs/
         porting_log.md       full porting journal (step-by-step)
         cloverleaf_build.txt
         graph500_make.txt
         raxml_build.txt
         hpcc_build.txt
         lammps_build.txt
         lammps_cmake.txt
   README.md