[PATCH 3/3] tools/nolibc: add support for hexagon
From: Thomas Weißschuh
Date: Wed Aug 19 2026 - 02:32:48 EST
A mostly straightforward new architecture with a few quirks:
* Only qemu-user is supported for testing.
* Clang is required for compilation.
* -fsanitize=undefined is broken.
Signed-off-by: Thomas Weißschuh <linux@xxxxxxxxxxxxxx>
---
tools/include/nolibc/Makefile | 1 +
tools/include/nolibc/arch-hexagon.h | 164 +++++++++++++++++++++++++
tools/include/nolibc/arch.h | 2 +
tools/testing/selftests/nolibc/Makefile.nolibc | 8 ++
tools/testing/selftests/nolibc/run-tests.sh | 6 +
5 files changed, 181 insertions(+)
diff --git a/tools/include/nolibc/Makefile b/tools/include/nolibc/Makefile
index b5897b3964f8..c4a0879e4140 100644
--- a/tools/include/nolibc/Makefile
+++ b/tools/include/nolibc/Makefile
@@ -21,6 +21,7 @@ architectures := \
alpha \
arm \
arm64 \
+ hexagon \
loongarch \
m68k \
mips \
diff --git a/tools/include/nolibc/arch-hexagon.h b/tools/include/nolibc/arch-hexagon.h
new file mode 100644
index 000000000000..2dcc69a47e9f
--- /dev/null
+++ b/tools/include/nolibc/arch-hexagon.h
@@ -0,0 +1,164 @@
+/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
+/*
+ * hexagon specific definitions for NOLIBC
+ * Copyright (C) 2026 Thomas Weißschuh <linux@xxxxxxxxxxxxxx>
+ */
+
+#ifndef _NOLIBC_ARCH_HEXAGON_H
+#define _NOLIBC_ARCH_HEXAGON_H
+
+#include <linux/unistd.h>
+
+#include "compiler.h"
+#include "crt.h"
+
+/*
+ * Syscalls for OpenRISC:
+ * - syscall number is passed in r6
+ * - arguments are in r0, r1, r2, r3, r4, r5
+ * - the system call is performed by calling trap0(#1)
+ * - syscall return value is in r0
+ */
+
+#define _NOLIBC_SYSCALL_CLOBBERLIST "memory"
+
+#define __nolibc_syscall0(num) \
+({ \
+ register long _num __asm__ ("r6") = (num); \
+ register long _arg1 __asm__ ("r0"); \
+ \
+ __asm__ volatile ( \
+ "trap0(#1)\n" \
+ : "=r"(_arg1) \
+ : "r"(_num) \
+ : _NOLIBC_SYSCALL_CLOBBERLIST \
+ ); \
+ _arg1; \
+})
+
+#define __nolibc_syscall1(num, arg1) \
+({ \
+ register long _num __asm__ ("r6") = (num); \
+ register long _arg1 __asm__ ("r0") = (long)(arg1); \
+ \
+ __asm__ volatile ( \
+ "trap0(#1)\n" \
+ : "+r"(_arg1) \
+ : "r"(_num) \
+ : _NOLIBC_SYSCALL_CLOBBERLIST \
+ ); \
+ _arg1; \
+})
+
+#define __nolibc_syscall2(num, arg1, arg2) \
+({ \
+ register long _num __asm__ ("r6") = (num); \
+ register long _arg1 __asm__ ("r0") = (long)(arg1); \
+ register long _arg2 __asm__ ("r1") = (long)(arg2); \
+ \
+ __asm__ volatile ( \
+ "trap0(#1)\n" \
+ : "+r"(_arg1) \
+ : "r"(_arg2), \
+ "r"(_num) \
+ : _NOLIBC_SYSCALL_CLOBBERLIST \
+ ); \
+ _arg1; \
+})
+
+#define __nolibc_syscall3(num, arg1, arg2, arg3) \
+({ \
+ register long _num __asm__ ("r6") = (num); \
+ register long _arg1 __asm__ ("r0") = (long)(arg1); \
+ register long _arg2 __asm__ ("r1") = (long)(arg2); \
+ register long _arg3 __asm__ ("r2") = (long)(arg3); \
+ \
+ __asm__ volatile ( \
+ "trap0(#1)\n" \
+ : "+r"(_arg1) \
+ : "r"(_arg2), "r"(_arg3), \
+ "r"(_num) \
+ : _NOLIBC_SYSCALL_CLOBBERLIST \
+ ); \
+ _arg1; \
+})
+
+#define __nolibc_syscall4(num, arg1, arg2, arg3, arg4) \
+({ \
+ register long _num __asm__ ("r6") = (num); \
+ register long _arg1 __asm__ ("r0") = (long)(arg1); \
+ register long _arg2 __asm__ ("r1") = (long)(arg2); \
+ register long _arg3 __asm__ ("r2") = (long)(arg3); \
+ register long _arg4 __asm__ ("r3") = (long)(arg4); \
+ \
+ __asm__ volatile ( \
+ "trap0(#1)\n" \
+ : "+r"(_arg1) \
+ : "r"(_arg2), "r"(_arg3), "r"(_arg4), \
+ "r"(_num) \
+ : _NOLIBC_SYSCALL_CLOBBERLIST \
+ ); \
+ _arg1; \
+})
+
+#define __nolibc_syscall5(num, arg1, arg2, arg3, arg4, arg5) \
+({ \
+ register long _num __asm__ ("r6") = (num); \
+ register long _arg1 __asm__ ("r0") = (long)(arg1); \
+ register long _arg2 __asm__ ("r1") = (long)(arg2); \
+ register long _arg3 __asm__ ("r2") = (long)(arg3); \
+ register long _arg4 __asm__ ("r3") = (long)(arg4); \
+ register long _arg5 __asm__ ("r4") = (long)(arg5); \
+ \
+ __asm__ volatile ( \
+ "trap0(#1)\n" \
+ : "+r"(_arg1) \
+ : "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), \
+ "r"(_num) \
+ : _NOLIBC_SYSCALL_CLOBBERLIST \
+ ); \
+ _arg1; \
+})
+
+#define __nolibc_syscall6(num, arg1, arg2, arg3, arg4, arg5, arg6) \
+({ \
+ register long _num __asm__ ("r6") = (num); \
+ register long _arg1 __asm__ ("r0") = (long)(arg1); \
+ register long _arg2 __asm__ ("r1") = (long)(arg2); \
+ register long _arg3 __asm__ ("r2") = (long)(arg3); \
+ register long _arg4 __asm__ ("r3") = (long)(arg4); \
+ register long _arg5 __asm__ ("r4") = (long)(arg5); \
+ register long _arg6 __asm__ ("r5") = (long)(arg6); \
+ \
+ __asm__ volatile ( \
+ "trap0(#1)\n" \
+ : "+r"(_arg1) \
+ : "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), "r"(_arg6), \
+ "r"(_num) \
+ : _NOLIBC_SYSCALL_CLOBBERLIST \
+ ); \
+ _arg1; \
+})
+
+#ifndef NOLIBC_NO_RUNTIME
+/* startup code */
+void __attribute__((weak, noreturn))
+__nolibc_entrypoint __nolibc_no_stack_protector
+_start(void)
+{
+ __asm__ volatile (
+ "r0 = sp\n" /* save stack pointer to r0, as arg1 of _start_c */
+ "call _start_c\n" /* transfer to c runtime */
+ );
+ __nolibc_entrypoint_epilogue();
+}
+#endif /* NOLIBC_NO_RUNTIME */
+
+static __attribute__((unused))
+int _sys_ftruncate64(int fd, uint32_t length0, uint32_t length1)
+{
+ return __nolibc_syscall4(__NR_ftruncate64, fd, 0, length0, length1);
+}
+#define _sys_ftruncate64 _sys_ftruncate64
+
+#endif /* _NOLIBC_ARCH_HEXAGON_H */
diff --git a/tools/include/nolibc/arch.h b/tools/include/nolibc/arch.h
index 06cc2dbe7a33..24e0ec4fb2db 100644
--- a/tools/include/nolibc/arch.h
+++ b/tools/include/nolibc/arch.h
@@ -34,6 +34,8 @@
#include "arch-parisc.h"
#elif defined(__alpha__)
#include "arch-alpha.h"
+#elif defined(__hexagon__)
+#include "arch-hexagon.h"
#else
#error Unsupported Architecture
#endif
diff --git a/tools/testing/selftests/nolibc/Makefile.nolibc b/tools/testing/selftests/nolibc/Makefile.nolibc
index f70c8dfca018..439677cbc5cf 100644
--- a/tools/testing/selftests/nolibc/Makefile.nolibc
+++ b/tools/testing/selftests/nolibc/Makefile.nolibc
@@ -206,6 +206,8 @@ CFLAGS_mips64be = -EB -mabi=64 -march=mips64r2
CFLAGS_loongarch = $(if $(LLVM),-fuse-ld=lld)
CFLAGS_sparc32 = $(call cc-option,-m32) -mcpu=v8
CFLAGS_sh4 = -ml -m4
+# github.com/llvm/llvm-project/issues/216765
+CFLAGS_hexagon = -fno-sanitize=undefined
ifeq ($(origin XARCH),command line)
CFLAGS_XARCH = $(CFLAGS_$(XARCH))
endif
@@ -222,6 +224,12 @@ LDFLAGS :=
# Modify CFLAGS based on LLVM=
include $(srctree)/tools/scripts/Makefile.include
+ifeq ($(ARCH),hexagon)
+# tools/scripts/Makefile.include requires CROSS_COMPILE which does not exist for hexagon
+CFLAGS += --target=hexagon-linux-musl
+CLANG_CROSS_FLAGS += --target=hexagon-linux-musl
+endif
+
REPORT ?= awk '/\[OK\][\r]*$$/{p++} /\[FAIL\][\r]*$$/{if (!f) printf("\n"); f++; print;} /\[SKIPPED\][\r]*$$/{s++} \
/^Total number of errors:/{done++} \
END{ printf("\n%3d test(s): %3d passed, %3d skipped, %3d failed => status: ", p+s+f, p, s, f); \
diff --git a/tools/testing/selftests/nolibc/run-tests.sh b/tools/testing/selftests/nolibc/run-tests.sh
index 5732b956ead9..3da806e2b302 100755
--- a/tools/testing/selftests/nolibc/run-tests.sh
+++ b/tools/testing/selftests/nolibc/run-tests.sh
@@ -31,6 +31,7 @@ all_archs=(
sh4
parisc32
alpha
+ hexagon
)
archs="${all_archs[@]}"
@@ -134,6 +135,7 @@ crosstool_abi() {
need_gcc() {
case "$1" in
+ hexagon);;
*) echo "1";;
esac
}
@@ -212,6 +214,10 @@ test_arch() {
echo "Unsupported configuration"
return
fi
+ if [ "$arch" = "hexagon" ] && [ -z "$llvm" -o "$test_mode" = "system" ]; then
+ echo "Unsupported configuration"
+ return
+ fi
mkdir -p "$build_dir"
swallow_output "${MAKE[@]}" defconfig
--
2.55.0