diff --git a/devel/hpx/Makefile b/devel/hpx/Makefile
index b444af01ac32..1f7a520be8aa 100644
--- a/devel/hpx/Makefile
+++ b/devel/hpx/Makefile
@@ -1,37 +1,39 @@
 PORTNAME=	hpx
 DISTVERSION=	1.8.0
 CATEGORIES=	devel
 
 MAINTAINER=	yuri@FreeBSD.org
 COMMENT=	C++ Standard Library for Parallelism and Concurrency
 
 LICENSE=	BSL
 LICENSE_FILE=	${WRKSRC}/LICENSE_1_0.txt
 
+BROKEN_riscv64=	hpx/hardware/timestamp.hpp:43:6: error: Unsupported platform
+
 BUILD_DEPENDS=	asio>0:net/asio
 LIB_DEPENDS=	libboost_filesystem.so:devel/boost-libs \
 		libhwloc.so.15:devel/hwloc2
 
 USES=		cmake:testing compiler:c++17-lang python shebangfix
 USE_LDCONFIG=	yes
 
 USE_GITHUB=	yes
 GH_ACCOUNT=	STEllAR-GROUP
 
 SHEBANG_FILES=	cmake/templates/hpxrun.py.in cmake/templates/hpxcxx.in
 SHEBANG_GLOB=	*.py
 
 CMAKE_ON=	HPX_WITH_GENERIC_CONTEXT_COROUTINES
 CMAKE_OFF=	HPX_WITH_EXAMPLES HPX_WITH_TESTS HPX_WITH_TESTS_BENCHMARKS HPX_WITH_TESTS_REGRESSIONS HPX_WITH_TESTS_UNIT HPX_WITH_TESTS_EXAMPLES
 CMAKE_TESTING_ON=	HPX_WITH_TESTS HPX_WITH_TESTS_UNIT # tests fail: https://github.com/STEllAR-GROUP/hpx/issues/5893
 
 LDFLAGS+=	${LDFLAGS_${CHOSEN_COMPILER_TYPE}}
 LDFLAGS_gcc=	-latomic
 
 BINARY_ALIAS=	git=false
 
 post-install:
 	@${RM} ${STAGEDIR}${DATADIR}/LICENSE_1_0.txt
 	@${RMDIR} ${STAGEDIR}${DATADIR}
 
 .include <bsd.port.mk>