tools/nolibc: Add support for SPARC

Add support for 32bit and 64bit SPARC to nolibc.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Acked-by: Willy Tarreau <w@1wt.eu>
Tested-by: Sebastian Andrzej Siewior <sebastian@breakpoint.cc> # UltraSparc T4 (Niagara4)
Link: https://lore.kernel.org/lkml/20250322-nolibc-sparc-v2-1-89af018c6296@weissschuh.net/

2 files changed, 193 insertions, 0 deletions

diff --git a/tools/include/nolibc/arch-sparc.h b/tools/include/nolibc/arch-sparc.h
new file mode 100644
index 000000000000..1435172f3dfe
--- /dev/null
+++ b/tools/include/nolibc/arch-sparc.h
@@ -0,0 +1,191 @@
+/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
+/*
+ * SPARC (32bit and 64bit) specific definitions for NOLIBC
+ * Copyright (C) 2025 Thomas Weißschuh <linux@weissschuh.net>
+ */
+
+#ifndef _NOLIBC_ARCH_SPARC_H
+#define _NOLIBC_ARCH_SPARC_H
+
+#include <linux/unistd.h>
+
+#include "compiler.h"
+#include "crt.h"
+
+/*
+ * Syscalls for SPARC:
+ *   - registers are native word size
+ *   - syscall number is passed in g1
+ *   - arguments are in o0-o5
+ *   - the system call is performed by calling a trap instruction
+ *   - syscall return value is in o0
+ *   - syscall error flag is in the carry bit of the processor status register
+ */
+
+#ifdef __arch64__
+
+#define _NOLIBC_SYSCALL "t	0x6d\n"                                       \
+			"bcs,a	%%xcc, 1f\n"                                  \
+			"sub	%%g0, %%o0, %%o0\n"                           \
+			"1:\n"
+
+#else
+
+#define _NOLIBC_SYSCALL "t	0x10\n"                                       \
+			"bcs,a	1f\n"                                         \
+			"sub	%%g0, %%o0, %%o0\n"                           \
+			"1:\n"
+
+#endif /* __arch64__ */
+
+#define my_syscall0(num)                                                      \
+({                                                                            \
+	register long _num  __asm__ ("g1") = (num);                           \
+	register long _arg1 __asm__ ("o0");                                   \
+									      \
+	__asm__ volatile (                                                    \
+		_NOLIBC_SYSCALL                                               \
+		: "+r"(_arg1)                                                 \
+		: "r"(_num)                                                   \
+		: "memory", "cc"                                              \
+	);                                                                    \
+	_arg1;                                                                \
+})
+
+#define my_syscall1(num, arg1)                                                \
+({                                                                            \
+	register long _num  __asm__ ("g1") = (num);                           \
+	register long _arg1 __asm__ ("o0") = (long)(arg1);                    \
+									      \
+	__asm__ volatile (                                                    \
+		_NOLIBC_SYSCALL                                               \
+		: "+r"(_arg1)                                                 \
+		: "r"(_num)                                                   \
+		: "memory", "cc"                                              \
+	);                                                                    \
+	_arg1;                                                                \
+})
+
+#define my_syscall2(num, arg1, arg2)                                          \
+({                                                                            \
+	register long _num  __asm__ ("g1") = (num);                           \
+	register long _arg1 __asm__ ("o0") = (long)(arg1);                    \
+	register long _arg2 __asm__ ("o1") = (long)(arg2);                    \
+									      \
+	__asm__ volatile (                                                    \
+		_NOLIBC_SYSCALL                                               \
+		: "+r"(_arg1)                                                 \
+		: "r"(_arg2), "r"(_num)                                       \
+		: "memory", "cc"                                              \
+	);                                                                    \
+	_arg1;                                                                \
+})
+
+#define my_syscall3(num, arg1, arg2, arg3)                                    \
+({                                                                            \
+	register long _num  __asm__ ("g1") = (num);                           \
+	register long _arg1 __asm__ ("o0") = (long)(arg1);                    \
+	register long _arg2 __asm__ ("o1") = (long)(arg2);                    \
+	register long _arg3 __asm__ ("o2") = (long)(arg3);                    \
+									      \
+	__asm__ volatile (                                                    \
+		_NOLIBC_SYSCALL                                               \
+		: "+r"(_arg1)                                                 \
+		: "r"(_arg2), "r"(_arg3), "r"(_num)                           \
+		: "memory", "cc"                                              \
+	);                                                                    \
+	_arg1;                                                                \
+})
+
+#define my_syscall4(num, arg1, arg2, arg3, arg4)                              \
+({                                                                            \
+	register long _num  __asm__ ("g1") = (num);                           \
+	register long _arg1 __asm__ ("o0") = (long)(arg1);                    \
+	register long _arg2 __asm__ ("o1") = (long)(arg2);                    \
+	register long _arg3 __asm__ ("o2") = (long)(arg3);                    \
+	register long _arg4 __asm__ ("o3") = (long)(arg4);                    \
+									      \
+	__asm__ volatile (                                                    \
+		_NOLIBC_SYSCALL                                               \
+		: "+r"(_arg1)                                                 \
+		: "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_num)               \
+		: "memory", "cc"                                              \
+	);                                                                    \
+	_arg1;                                                                \
+})
+
+#define my_syscall5(num, arg1, arg2, arg3, arg4, arg5)                        \
+({                                                                            \
+	register long _num  __asm__ ("g1") = (num);                           \
+	register long _arg1 __asm__ ("o0") = (long)(arg1);                    \
+	register long _arg2 __asm__ ("o1") = (long)(arg2);                    \
+	register long _arg3 __asm__ ("o2") = (long)(arg3);                    \
+	register long _arg4 __asm__ ("o3") = (long)(arg4);                    \
+	register long _arg5 __asm__ ("o4") = (long)(arg5);                    \
+									      \
+	__asm__ volatile (                                                    \
+		_NOLIBC_SYSCALL                                               \
+		: "+r"(_arg1)                                                 \
+		: "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), "r"(_num)   \
+		: "memory", "cc"                                              \
+	);                                                                    \
+	_arg1;                                                                \
+})
+
+#define my_syscall6(num, arg1, arg2, arg3, arg4, arg5, arg6)                  \
+({                                                                            \
+	register long _num  __asm__ ("g1") = (num);                           \
+	register long _arg1 __asm__ ("o0") = (long)(arg1);                    \
+	register long _arg2 __asm__ ("o1") = (long)(arg2);                    \
+	register long _arg3 __asm__ ("o2") = (long)(arg3);                    \
+	register long _arg4 __asm__ ("o3") = (long)(arg4);                    \
+	register long _arg5 __asm__ ("o4") = (long)(arg5);                    \
+	register long _arg6 __asm__ ("o5") = (long)(arg6);                    \
+									      \
+	__asm__ volatile (                                                    \
+		_NOLIBC_SYSCALL                                               \
+		: "+r"(_arg1)                                                 \
+		: "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), "r"(_arg6), \
+		  "r"(_num)                                                   \
+		: "memory", "cc"                                              \
+	);                                                                    \
+	_arg1;                                                                \
+})
+
+/* startup code */
+void __attribute__((weak, noreturn)) __nolibc_entrypoint __no_stack_protector _start(void)
+{
+	__asm__ volatile (
+		/*
+		 * Save argc pointer to o0, as arg1 of _start_c.
+		 * Account for the window save area, which is 16 registers wide.
+		 */
+#ifdef __arch64__
+		"add %sp, 128 + 2047, %o0\n" /* on sparc64 / v9 the stack is offset by 2047 */
+#else
+		"add %sp, 64, %o0\n"
+#endif
+		"b,a _start_c\n"     /* transfer to c runtime */
+	);
+	__nolibc_entrypoint_epilogue();
+}
+
+static pid_t getpid(void);
+
+static __attribute__((unused))
+pid_t sys_fork(void)
+{
+	pid_t parent, ret;
+
+	parent = getpid();
+	ret = my_syscall0(__NR_fork);
+
+	/* The syscall returns the parent pid in the child instead of 0 */
+	if (ret == parent)
+		return 0;
+	else
+		return ret;
+}
+#define sys_fork sys_fork
+
+#endif /* _NOLIBC_ARCH_SPARC_H */
diff --git a/tools/include/nolibc/arch.h b/tools/include/nolibc/arch.h
index 8a2c143c0fba..b8c1da9a88d1 100644
--- a/tools/include/nolibc/arch.h
+++ b/tools/include/nolibc/arch.h
@@ -33,6 +33,8 @@
 #include "arch-s390.h"
 #elif defined(__loongarch__)
 #include "arch-loongarch.h"
+#elif defined(__sparc__)
+#include "arch-sparc.h"
 #else
 #error Unsupported Architecture
 #endif