[PATCH] tools/nolibc: add support for OpenRISC / or1k
From: Thomas Weißschuh
Date: Tue Apr 28 2026 - 11:50:46 EST
Add support for OpenRISC / or1k to nolibc.
_start() uses the same wrapper construct as in arch-sh.h.
libgcc is necessary as OpenRISC is missing 64-bit multiplication.
Signed-off-by: Thomas Weißschuh <linux@xxxxxxxxxxxxxx>
---
tools/include/nolibc/Makefile | 2 +-
tools/include/nolibc/arch-openrisc.h | 176 +++++++++++++++++++++++++
tools/include/nolibc/arch.h | 2 +
tools/testing/selftests/nolibc/Makefile.nolibc | 5 +
tools/testing/selftests/nolibc/run-tests.sh | 4 +-
5 files changed, 187 insertions(+), 2 deletions(-)
diff --git a/tools/include/nolibc/Makefile b/tools/include/nolibc/Makefile
index 872c318f50d4..2cb4d610fe53 100644
--- a/tools/include/nolibc/Makefile
+++ b/tools/include/nolibc/Makefile
@@ -17,7 +17,7 @@ endif
# it defaults to this nolibc directory.
OUTPUT ?= $(CURDIR)/
-architectures := arm arm64 loongarch m68k mips powerpc riscv s390 sh sparc x86
+architectures := arm arm64 loongarch m68k mips openrisc powerpc riscv s390 sh sparc x86
arch_files := arch.h $(addsuffix .h, $(addprefix arch-, $(architectures)))
all_files := \
alloca.h \
diff --git a/tools/include/nolibc/arch-openrisc.h b/tools/include/nolibc/arch-openrisc.h
new file mode 100644
index 000000000000..de2df1715504
--- /dev/null
+++ b/tools/include/nolibc/arch-openrisc.h
@@ -0,0 +1,176 @@
+/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
+/*
+ * openrisc specific definitions for NOLIBC
+ * Copyright (C) 2026 Thomas Weißschuh <linux@xxxxxxxxxxxxxx>
+ */
+
+#ifndef _NOLIBC_ARCH_OPENRISC_H
+#define _NOLIBC_ARCH_OPENRISC_H
+
+#include "compiler.h"
+#include "crt.h"
+
+/*
+ * Syscalls for SuperH:
+ * - syscall number is passed in r11
+ * - arguments are in r3, r4, r5, r6, r7, r8
+ * - the system call is performed by calling l.sys 1
+ * - syscall return value is in r11
+ */
+
+#define _NOLIBC_SYSCALL_CLOBBERLIST \
+ "r12", "r13", "r15", "r17", "r19", "r21", "r23", "r25", "r27", "r29", "r31", "memory"
+
+#define __nolibc_syscall0(num) \
+({ \
+ register long _num __asm__ ("r11") = (num); \
+ register long _ret __asm__ ("r11"); \
+ \
+ __asm__ volatile ( \
+ "l.sys 1\n" \
+ "l.nop\n" \
+ : "=r"(_ret) \
+ : "r"(_num) \
+ : "r3", "r4", "r5", "r6", "r7", "r8", \
+ _NOLIBC_SYSCALL_CLOBBERLIST \
+ ); \
+ _ret; \
+})
+
+#define __nolibc_syscall1(num, arg1) \
+({ \
+ register long _num __asm__ ("r11") = (num); \
+ register long _ret __asm__ ("r11"); \
+ register long _arg1 __asm__ ("r3") = (long)(arg1); \
+ \
+ __asm__ volatile ( \
+ "l.sys 1\n" \
+ "l.nop\n" \
+ : "=r"(_ret) \
+ : "r"(_num), "r"(_arg1) \
+ : "r4", "r5", "r6", "r7", "r8", _NOLIBC_SYSCALL_CLOBBERLIST \
+ ); \
+ _ret; \
+})
+
+#define __nolibc_syscall2(num, arg1, arg2) \
+({ \
+ register long _num __asm__ ("r11") = (num); \
+ register long _ret __asm__ ("r11"); \
+ register long _arg1 __asm__ ("r3") = (long)(arg1); \
+ register long _arg2 __asm__ ("r4") = (long)(arg2); \
+ \
+ __asm__ volatile ( \
+ "l.sys 1\n" \
+ "l.nop\n" \
+ : "=r"(_ret) \
+ : "r"(_num), "r"(_arg1), "r"(_arg2) \
+ : "r5", "r6", "r7", "r8", _NOLIBC_SYSCALL_CLOBBERLIST \
+ ); \
+ _ret; \
+})
+
+#define __nolibc_syscall3(num, arg1, arg2, arg3) \
+({ \
+ register long _num __asm__ ("r11") = (num); \
+ register long _ret __asm__ ("r11"); \
+ register long _arg1 __asm__ ("r3") = (long)(arg1); \
+ register long _arg2 __asm__ ("r4") = (long)(arg2); \
+ register long _arg3 __asm__ ("r5") = (long)(arg3); \
+ \
+ __asm__ volatile ( \
+ "l.sys 1\n" \
+ "l.nop\n" \
+ : "=r"(_ret) \
+ : "r"(_num), "r"(_arg1), "r"(_arg2), "r"(_arg3) \
+ : "r6", "r7", "r8", _NOLIBC_SYSCALL_CLOBBERLIST \
+ ); \
+ _ret; \
+})
+
+#define __nolibc_syscall4(num, arg1, arg2, arg3, arg4) \
+({ \
+ register long _num __asm__ ("r11") = (num); \
+ register long _ret __asm__ ("r11"); \
+ register long _arg1 __asm__ ("r3") = (long)(arg1); \
+ register long _arg2 __asm__ ("r4") = (long)(arg2); \
+ register long _arg3 __asm__ ("r5") = (long)(arg3); \
+ register long _arg4 __asm__ ("r6") = (long)(arg4); \
+ \
+ __asm__ volatile ( \
+ "l.sys 1\n" \
+ "l.nop\n" \
+ : "=r"(_ret) \
+ : "r"(_num), "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4) \
+ : "r7", "r8", _NOLIBC_SYSCALL_CLOBBERLIST \
+ ); \
+ _ret; \
+})
+
+#define __nolibc_syscall5(num, arg1, arg2, arg3, arg4, arg5) \
+({ \
+ register long _num __asm__ ("r11") = (num); \
+ register long _ret __asm__ ("r11"); \
+ register long _arg1 __asm__ ("r3") = (long)(arg1); \
+ register long _arg2 __asm__ ("r4") = (long)(arg2); \
+ register long _arg3 __asm__ ("r5") = (long)(arg3); \
+ register long _arg4 __asm__ ("r6") = (long)(arg4); \
+ register long _arg5 __asm__ ("r7") = (long)(arg5); \
+ \
+ __asm__ volatile ( \
+ "l.sys 1\n" \
+ "l.nop\n" \
+ : "=r"(_ret) \
+ : "r"(_num), "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), \
+ "r"(_arg5) \
+ : "r8", _NOLIBC_SYSCALL_CLOBBERLIST \
+ ); \
+ _ret; \
+})
+
+#define __nolibc_syscall6(num, arg1, arg2, arg3, arg4, arg5, arg6) \
+({ \
+ register long _num __asm__ ("r11") = (num); \
+ register long _ret __asm__ ("r11"); \
+ register long _arg1 __asm__ ("r3") = (long)(arg1); \
+ register long _arg2 __asm__ ("r4") = (long)(arg2); \
+ register long _arg3 __asm__ ("r5") = (long)(arg3); \
+ register long _arg4 __asm__ ("r6") = (long)(arg4); \
+ register long _arg5 __asm__ ("r7") = (long)(arg5); \
+ register long _arg6 __asm__ ("r8") = (long)(arg6); \
+ \
+ __asm__ volatile ( \
+ "l.sys 1\n" \
+ "l.nop\n" \
+ : "=r"(_ret) \
+ : "r"(_num), "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), \
+ "r"(_arg5), "r"(_arg6) \
+ : _NOLIBC_SYSCALL_CLOBBERLIST \
+ ); \
+ _ret; \
+})
+
+#ifndef NOLIBC_NO_RUNTIME
+/* startup code */
+void _start_wrapper(void);
+void __attribute__((weak,noreturn))
+__nolibc_entrypoint __nolibc_no_stack_protector
+_start_wrapper(void)
+{
+ __asm__ volatile (
+ ".global _start\n" /* The C function will have a prologue, */
+ ".type _start, @function\n" /* corrupting "sp" */
+ ".weak _start\n"
+ "_start:\n"
+
+ "l.or r3,sp,sp\n" /* save stack pointer to 3, as arg1 of _start_c */
+ "l.jal _start_c\n" /* transfer to c runtime */
+ "l.nop\n"
+
+ ".size _start, .-_start\n"
+ );
+ __nolibc_entrypoint_epilogue();
+}
+#endif /* NOLIBC_NO_RUNTIME */
+
+#endif /* _NOLIBC_ARCH_OPENRISC_H */
diff --git a/tools/include/nolibc/arch.h b/tools/include/nolibc/arch.h
index a3adaf433f2c..55009dcafe9e 100644
--- a/tools/include/nolibc/arch.h
+++ b/tools/include/nolibc/arch.h
@@ -28,6 +28,8 @@
#include "arch-m68k.h"
#elif defined(__sh__)
#include "arch-sh.h"
+#elif defined(__or1k__)
+#include "arch-openrisc.h"
#else
#error Unsupported Architecture
#endif
diff --git a/tools/testing/selftests/nolibc/Makefile.nolibc b/tools/testing/selftests/nolibc/Makefile.nolibc
index f30bc68470cc..91f5a284f4e6 100644
--- a/tools/testing/selftests/nolibc/Makefile.nolibc
+++ b/tools/testing/selftests/nolibc/Makefile.nolibc
@@ -92,6 +92,7 @@ IMAGE_sparc32 = arch/sparc/boot/image
IMAGE_sparc64 = arch/sparc/boot/image
IMAGE_m68k = vmlinux
IMAGE_sh4 = arch/sh/boot/zImage
+IMAGE_openrisc = vmlinux
IMAGE = $(objtree)/$(IMAGE_$(XARCH))
IMAGE_NAME = $(notdir $(IMAGE))
@@ -121,6 +122,7 @@ DEFCONFIG_sparc32 = sparc32_defconfig
DEFCONFIG_sparc64 = sparc64_defconfig
DEFCONFIG_m68k = virt_defconfig
DEFCONFIG_sh4 = rts7751r2dplus_defconfig
+DEFCONFIG_openrisc = virt_defconfig
DEFCONFIG = $(DEFCONFIG_$(XARCH))
EXTRACONFIG_x32 = -e CONFIG_X86_X32_ABI
@@ -159,6 +161,7 @@ QEMU_ARCH_sparc32 = sparc
QEMU_ARCH_sparc64 = sparc64
QEMU_ARCH_m68k = m68k
QEMU_ARCH_sh4 = sh4
+QEMU_ARCH_openrisc = or1k
QEMU_ARCH = $(QEMU_ARCH_$(XARCH))
QEMU_ARCH_USER_ppc64le = ppc64le
@@ -199,6 +202,7 @@ QEMU_ARGS_sparc32 = -M SS-5 -m 256M -append "console=ttyS0,115200 panic=-1 $(
QEMU_ARGS_sparc64 = -M sun4u -append "console=ttyS0,115200 panic=-1 $(TEST:%=NOLIBC_TEST=%)"
QEMU_ARGS_m68k = -M virt -append "console=ttyGF0,115200 panic=-1 $(TEST:%=NOLIBC_TEST=%)"
QEMU_ARGS_sh4 = -M r2d -serial file:/dev/stdout -append "console=ttySC1,115200 panic=-1 $(TEST:%=NOLIBC_TEST=%)"
+QEMU_ARGS_openrisc = -M virt -m 512M -append "console=ttyS0 panic=-1 $(TEST:%=NOLIBC_TEST=%)"
QEMU_ARGS = -m 1G $(QEMU_ARGS_$(XARCH)) $(QEMU_ARGS_BIOS) $(QEMU_ARGS_EXTRA)
# OUTPUT is only set when run from the main makefile, otherwise
@@ -233,6 +237,7 @@ CFLAGS_XARCH = $(CFLAGS_$(XARCH))
endif
LDLIBS_ppc = $(if $(LLVM),,-lgcc)
+LDLIBS_openrisc = $(if $(LLVM),,-lgcc)
LDLIBS = $(LDLIBS_$(XARCH))
include Makefile.include
diff --git a/tools/testing/selftests/nolibc/run-tests.sh b/tools/testing/selftests/nolibc/run-tests.sh
index cd439096fdf3..c25ee4be2df4 100755
--- a/tools/testing/selftests/nolibc/run-tests.sh
+++ b/tools/testing/selftests/nolibc/run-tests.sh
@@ -21,6 +21,7 @@ all_archs=(
i386 x86_64 x32
arm64 arm armthumb
mips32le mips32be mipsn32le mipsn32be mips64le mips64be
+ openrisc
ppc ppc64 ppc64le
riscv32 riscv64
s390x
@@ -107,6 +108,7 @@ crosstool_arch() {
case "$1" in
arm64) echo aarch64;;
armthumb) echo arm;;
+ openrisc) echo or1k;;
ppc) echo powerpc;;
ppc64) echo powerpc64;;
ppc64le) echo powerpc64;;
@@ -185,7 +187,7 @@ test_arch() {
exit 1
esac
printf '%-15s' "$arch:"
- if [ "$arch" = "m68k" -o "$arch" = "sh4" ] && [ "$llvm" = "1" ]; then
+ if [ "$arch" = "m68k" -o "$arch" = "sh4" -o "$arch" = "openrisc" ] && [ "$llvm" = "1" ]; then
echo "Unsupported configuration"
return
fi
---
base-commit: 8bf37d924968cf26ab95f644c981a28086e372af
change-id: 20260415-nolibc-openrisc-a1ab91c41fe5
Best regards,
--
Thomas Weißschuh <linux@xxxxxxxxxxxxxx>