std.os.linux: add csky arch bits

closes https://codeberg.org/ziglang/zig/issues/30942

lib/std/os/linux.zig

@@ -35,6 +35,7 @@ const arch_bits = switch (native_arch) {
     .alpha => @import("linux/alpha.zig"),
     .arc, .arceb => @import("linux/arc.zig"),
     .arm, .armeb, .thumb, .thumbeb => @import("linux/arm.zig"),
+    .csky => @import("linux/csky.zig"),
     .hexagon => @import("linux/hexagon.zig"),
     .loongarch32 => @import("linux/loongarch32.zig"),
     .loongarch64 => @import("linux/loongarch64.zig"),
@@ -288,6 +289,7 @@ pub const MAP = switch (native_arch) {
     },
     .arc,
     .arceb,
+    .csky,
     .hexagon,
     .m68k,
     .or1k,
@@ -518,6 +520,7 @@ pub const O = switch (native_arch) {
     },
     .arc,
     .arceb,
+    .csky,
     .hexagon,
     .or1k,
     .s390x,
@@ -6633,7 +6636,7 @@ pub const k_sigaction = switch (native_arch) {
         handler: k_sigaction_funcs.handler,
         mask: sigset_t,
     },
-    .hexagon, .loongarch32, .loongarch64, .or1k, .riscv32, .riscv64 => extern struct {
+    .csky, .hexagon, .loongarch32, .loongarch64, .or1k, .riscv32, .riscv64 => extern struct {
         handler: k_sigaction_funcs.handler,
         flags: c_ulong,
         mask: sigset_t,

lib/std/os/linux/csky.zig

@@ -0,0 +1,165 @@
+const builtin = @import("builtin");
+const std = @import("../../std.zig");
+const SYS = std.os.linux.SYS;
+
+pub const syscall_arg_t = u32;
+
+pub fn syscall0(
+    number: SYS,
+) u32 {
+    return asm volatile ("trap 0"
+        : [ret] "={r0}" (-> u32),
+        : [number] "{r7}" (@intFromEnum(number)),
+        : .{ .memory = true });
+}
+
+pub fn syscall1(
+    number: SYS,
+    arg1: syscall_arg_t,
+) u32 {
+    return asm volatile ("trap 0"
+        : [ret] "={r0}" (-> u32),
+        : [number] "{r7}" (@intFromEnum(number)),
+          [arg1] "{r0}" (arg1),
+        : .{ .memory = true });
+}
+
+pub fn syscall2(
+    number: SYS,
+    arg1: syscall_arg_t,
+    arg2: syscall_arg_t,
+) u32 {
+    return asm volatile ("trap 0"
+        : [ret] "={r0}" (-> u32),
+        : [number] "{r7}" (@intFromEnum(number)),
+          [arg1] "{r0}" (arg1),
+          [arg2] "{r1}" (arg2),
+        : .{ .memory = true });
+}
+
+pub fn syscall3(
+    number: SYS,
+    arg1: syscall_arg_t,
+    arg2: syscall_arg_t,
+    arg3: syscall_arg_t,
+) u32 {
+    return asm volatile ("trap 0"
+        : [ret] "={r0}" (-> u32),
+        : [number] "{r7}" (@intFromEnum(number)),
+          [arg1] "{r0}" (arg1),
+          [arg2] "{r1}" (arg2),
+          [arg3] "{r2}" (arg3),
+        : .{ .memory = true });
+}
+
+pub fn syscall4(
+    number: SYS,
+    arg1: syscall_arg_t,
+    arg2: syscall_arg_t,
+    arg3: syscall_arg_t,
+    arg4: syscall_arg_t,
+) u32 {
+    return asm volatile ("trap 0"
+        : [ret] "={r0}" (-> u32),
+        : [number] "{r7}" (@intFromEnum(number)),
+          [arg1] "{r0}" (arg1),
+          [arg2] "{r1}" (arg2),
+          [arg3] "{r2}" (arg3),
+          [arg4] "{r3}" (arg4),
+        : .{ .memory = true });
+}
+
+pub fn syscall5(
+    number: SYS,
+    arg1: syscall_arg_t,
+    arg2: syscall_arg_t,
+    arg3: syscall_arg_t,
+    arg4: syscall_arg_t,
+    arg5: syscall_arg_t,
+) u32 {
+    return asm volatile ("trap 0"
+        : [ret] "={r0}" (-> u32),
+        : [number] "{r7}" (@intFromEnum(number)),
+          [arg1] "{r0}" (arg1),
+          [arg2] "{r1}" (arg2),
+          [arg3] "{r2}" (arg3),
+          [arg4] "{r3}" (arg4),
+          [arg5] "{r4}" (arg5),
+        : .{ .memory = true });
+}
+
+pub fn syscall6(
+    number: SYS,
+    arg1: syscall_arg_t,
+    arg2: syscall_arg_t,
+    arg3: syscall_arg_t,
+    arg4: syscall_arg_t,
+    arg5: syscall_arg_t,
+    arg6: syscall_arg_t,
+) u32 {
+    return asm volatile ("trap 0"
+        : [ret] "={r0}" (-> u32),
+        : [number] "{r7}" (@intFromEnum(number)),
+          [arg1] "{r0}" (arg1),
+          [arg2] "{r1}" (arg2),
+          [arg3] "{r2}" (arg3),
+          [arg4] "{r3}" (arg4),
+          [arg5] "{r4}" (arg5),
+          [arg6] "{r5}" (arg6),
+        : .{ .memory = true });
+}
+
+pub fn clone() callconv(.naked) u32 {
+    // __clone(func, stack, flags, arg, ptid, tls, ctid)
+    //         r0,   r1,    r2,    r3,  +0,   +4,  +8
+    //
+    // syscall(SYS_clone, flags, stack, ptid, tls, ctid)
+    //         r7         r0,    r1,    r2,   r3,  r4
+    asm volatile (
+        \\ // Preserve callee-saved registers.
+        \\ mov t0, r4
+        \\ mov t1, r7
+        \\
+        \\ andi r1, r1, -8
+        \\
+        \\ subi r1, 8
+        \\ stw r0, (r1, 0)
+        \\ stw r3, (r1, 4)
+        \\
+        \\ movi r7, 220 // SYS_clone
+        \\ mov r0, r2
+        \\ ldw r2, (sp, 0)
+        \\ ldw r3, (sp, 8)
+        \\ ldw r4, (sp, 4)
+        \\ trap 0
+        \\
+        \\ cmpnei r0, 0
+        \\ jbf 1f
+        \\
+        \\ // parent
+        \\ mov r7, t1
+        \\ mov r4, t0
+        \\ rts
+        \\
+        \\ // child
+        \\1:
+    );
+    if (builtin.unwind_tables != .none or !builtin.strip_debug_info) asm volatile (
+        \\ .cfi_undefined lr
+    );
+    asm volatile (
+        \\ movi r8, 0
+        \\ movi lr, 0
+        \\
+        \\ ldw r0, (sp, 4)
+        \\ ldw r1, (sp, 0)
+        \\ jsr r1
+        \\
+        \\ movi r7, 93 // SYS_exit
+        \\ trap 0
+    );
+}
+
+pub const time_t = i32;
+
+pub const VDSO = void;