From: Stafford Horne <shorne@gmail.com>
To: "Thomas Weißschuh" <linux@weissschuh.net>
Cc: Willy Tarreau <w@1wt.eu>, Jonas Bonn <jonas@southpole.se>,
Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>,
linux-openrisc@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] tools/nolibc: add support for OpenRISC / or1k
Date: Wed, 29 Apr 2026 19:43:08 +0100 [thread overview]
Message-ID: <afJRPLFAHt2aTmEr@antec> (raw)
In-Reply-To: <20260429-nolibc-openrisc-v2-1-8d7d7a2f3fec@weissschuh.net>
On Wed, Apr 29, 2026 at 05:20:45PM +0200, Thomas Weißschuh wrote:
> 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@weissschuh.net>
Acked-by: Stafford Horne <shorne@gmail.com>
Do you want me to pick this up to send via the openrisc queue? Or do you prefer
it go via the selftests queue?
> ---
> Changes in v2:
> - Drop useless l.nop from __nolibc_syscallX().
> - Use the delay slot after l.jal _start_c.
> - Fix some typos.
> - Use a single register variable for system call number and return.
> - Use 'r1' register name over non-idiomatic 'sp' alias.
> - Link to v1: https://patch.msgid.link/20260428-nolibc-openrisc-v1-1-33b399054af6@weissschuh.net
Thanks, I am ok with these. I didn't realize the 'sp' mnemonic worked. I
don't have any opinion either way as to whether we should use it or not, as I
suspect we have supported it in binutils/gas for a while. But I guess it's
safer to leave it out as I haven't seen it used before now.
-Stafford
> ---
> tools/include/nolibc/Makefile | 2 +-
> tools/include/nolibc/arch-openrisc.h | 160 +++++++++++++++++++++++++
> tools/include/nolibc/arch.h | 2 +
> tools/testing/selftests/nolibc/Makefile.nolibc | 5 +
> tools/testing/selftests/nolibc/run-tests.sh | 4 +-
> 5 files changed, 171 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..5ef82fd9cc64
> --- /dev/null
> +++ b/tools/include/nolibc/arch-openrisc.h
> @@ -0,0 +1,160 @@
> +/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
> +/*
> + * OpenRISC specific definitions for NOLIBC
> + * Copyright (C) 2026 Thomas Weißschuh <linux@weissschuh.net>
> + */
> +
> +#ifndef _NOLIBC_ARCH_OPENRISC_H
> +#define _NOLIBC_ARCH_OPENRISC_H
> +
> +#include "compiler.h"
> +#include "crt.h"
> +
> +/*
> + * Syscalls for OpenRISC:
> + * - 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); \
> + \
> + __asm__ volatile ( \
> + "l.sys 1\n" \
> + : "+r"(_num) \
> + : \
> + : "r3", "r4", "r5", "r6", "r7", "r8", \
> + _NOLIBC_SYSCALL_CLOBBERLIST \
> + ); \
> + _num; \
> +})
> +
> +#define __nolibc_syscall1(num, arg1) \
> +({ \
> + register long _num __asm__ ("r11") = (num); \
> + register long _arg1 __asm__ ("r3") = (long)(arg1); \
> + \
> + __asm__ volatile ( \
> + "l.sys 1\n" \
> + : "+r"(_num) \
> + : "r"(_arg1) \
> + : "r4", "r5", "r6", "r7", "r8", _NOLIBC_SYSCALL_CLOBBERLIST \
> + ); \
> + _num; \
> +})
> +
> +#define __nolibc_syscall2(num, arg1, arg2) \
> +({ \
> + register long _num __asm__ ("r11") = (num); \
> + register long _arg1 __asm__ ("r3") = (long)(arg1); \
> + register long _arg2 __asm__ ("r4") = (long)(arg2); \
> + \
> + __asm__ volatile ( \
> + "l.sys 1\n" \
> + : "+r"(_num) \
> + : "r"(_arg1), "r"(_arg2) \
> + : "r5", "r6", "r7", "r8", _NOLIBC_SYSCALL_CLOBBERLIST \
> + ); \
> + _num; \
> +})
> +
> +#define __nolibc_syscall3(num, arg1, arg2, arg3) \
> +({ \
> + register long _num __asm__ ("r11") = (num); \
> + 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" \
> + : "+r"(_num) \
> + : "r"(_arg1), "r"(_arg2), "r"(_arg3) \
> + : "r6", "r7", "r8", _NOLIBC_SYSCALL_CLOBBERLIST \
> + ); \
> + _num; \
> +})
> +
> +#define __nolibc_syscall4(num, arg1, arg2, arg3, arg4) \
> +({ \
> + register long _num __asm__ ("r11") = (num); \
> + 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" \
> + : "+r"(_num) \
> + : "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4) \
> + : "r7", "r8", _NOLIBC_SYSCALL_CLOBBERLIST \
> + ); \
> + _num; \
> +})
> +
> +#define __nolibc_syscall5(num, arg1, arg2, arg3, arg4, arg5) \
> +({ \
> + register long _num __asm__ ("r11") = (num); \
> + 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" \
> + : "+r"(_num) \
> + : "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5) \
> + : "r8", _NOLIBC_SYSCALL_CLOBBERLIST \
> + ); \
> + _num; \
> +})
> +
> +#define __nolibc_syscall6(num, arg1, arg2, arg3, arg4, arg5, arg6) \
> +({ \
> + register long _num __asm__ ("r11") = (num); \
> + 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" \
> + : "+r"(_num) \
> + : "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), \
> + "r"(_arg6) \
> + : _NOLIBC_SYSCALL_CLOBBERLIST \
> + ); \
> + _num; \
> +})
> +
> +#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/r1" */
> + ".weak _start\n"
> + "_start:\n"
> +
> + "l.jal _start_c\n" /* transfer to c runtime */
> + "l.or r3,r1,r1\n" /* save stack pointer to r3, as arg1 of _start_c */
> +
> + ".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@weissschuh.net>
>
next prev parent reply other threads:[~2026-04-29 18:43 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-29 15:20 [PATCH v2] tools/nolibc: add support for OpenRISC / or1k Thomas Weißschuh
2026-04-29 18:43 ` Stafford Horne [this message]
2026-04-29 20:58 ` Thomas Weißschuh
2026-05-01 7:59 ` Willy Tarreau
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