mmap_tls

inline fn mmap_tls(length: usize) usize {
    const prot: linux.PROT = .{ .READ = true, .WRITE = true };
    const flags: linux.MAP = .{ .TYPE = .PRIVATE, .ANONYMOUS = true };

    if (@hasField(linux.SYS, "mmap2")) {
        return @call(.always_inline, linux.syscall6, .{
            .mmap2,
            0,
            length,
            @as(u32, @bitCast(prot)),
            @as(u32, @bitCast(flags)),
            @as(usize, @bitCast(@as(isize, -1))),
            0,
        });
    } else {
        // The s390x mmap() syscall existed before Linux supported syscalls with 5+ parameters, so
        // it takes a single pointer to an array of arguments instead.
        return if (native_arch == .s390x) @call(.always_inline, linux.syscall1, .{
            .mmap,
            @intFromPtr(&[_]usize{
                0,
                length,
                @as(u32, @bitCast(prot)),
                @as(u32, @bitCast(flags)),
                @as(usize, @bitCast(@as(isize, -1))),
                0,
            }),
        }) else @call(.always_inline, linux.syscall6, .{
            .mmap,
            0,
            length,
            @as(u32, @bitCast(prot)),
            @as(u32, @bitCast(flags)),
            @as(usize, @bitCast(@as(isize, -1))),
            0,
        });
    }
}