linux_syscall_plain
void linux_syscall_plain(struct lwp *, uint64_t, struct trapframe *);
p->p_md.md_syscall = linux_syscall_plain;
p->p_md.md_syscall = linux_syscall_plain;
void linux_syscall_plain(struct trapframe *, struct lwp *, uint32_t);
p->p_md.md_syscall = linux_syscall_plain;
static void linux_syscall_plain(register_t, struct lwp *, struct frame *);