1 files changed, 476 insertions, 0 deletions
diff --git a/arch/um/kernel/tt/process_kern.c b/arch/um/kernel/tt/process_kern.c
new file mode 100644
index 0000000..f19f7c1
--- /dev/null
+++ b/arch/um/kernel/tt/process_kern.c
@@ -0,0 +1,476 @@
+/* 
+ * Copyright (C) 2002 Jeff Dike (jdike@karaya.com)
+ * Licensed under the GPL
+ */
+
+#include "linux/sched.h"
+#include "linux/signal.h"
+#include "linux/kernel.h"
+#include "linux/interrupt.h"
+#include "linux/ptrace.h"
+#include "asm/system.h"
+#include "asm/pgalloc.h"
+#include "asm/ptrace.h"
+#include "asm/tlbflush.h"
+#include "irq_user.h"
+#include "signal_user.h"
+#include "kern_util.h"
+#include "user_util.h"
+#include "os.h"
+#include "kern.h"
+#include "sigcontext.h"
+#include "time_user.h"
+#include "mem_user.h"
+#include "tlb.h"
+#include "mode.h"
+#include "init.h"
+#include "tt.h"
+
+void *switch_to_tt(void *prev, void *next, void *last)
+{
+	struct task_struct *from, *to, *prev_sched;
+	unsigned long flags;
+	int err, vtalrm, alrm, prof, cpu;
+	char c;
+	/* jailing and SMP are incompatible, so this doesn't need to be 
+	 * made per-cpu 
+	 */
+	static int reading;
+
+	from = prev;
+	to = next;
+
+	to->thread.prev_sched = from;
+
+	cpu = from->thread_info->cpu;
+	if(cpu == 0)
+		forward_interrupts(to->thread.mode.tt.extern_pid);
+#ifdef CONFIG_SMP
+	forward_ipi(cpu_data[cpu].ipi_pipe[0], to->thread.mode.tt.extern_pid);
+#endif
+	local_irq_save(flags);
+
+	vtalrm = change_sig(SIGVTALRM, 0);
+	alrm = change_sig(SIGALRM, 0);
+	prof = change_sig(SIGPROF, 0);
+
+	forward_pending_sigio(to->thread.mode.tt.extern_pid);
+
+	c = 0;
+	set_current(to);
+
+	reading = 0;
+	err = os_write_file(to->thread.mode.tt.switch_pipe[1], &c, sizeof(c));
+	if(err != sizeof(c))
+		panic("write of switch_pipe failed, err = %d", -err);
+
+	reading = 1;
+	if((from->exit_state == EXIT_ZOMBIE) ||
+	   (from->exit_state == EXIT_DEAD))
+		os_kill_process(os_getpid(), 0);
+
+	err = os_read_file(from->thread.mode.tt.switch_pipe[0], &c, sizeof(c));
+	if(err != sizeof(c))
+		panic("read of switch_pipe failed, errno = %d", -err);
+
+	/* If the process that we have just scheduled away from has exited,
+	 * then it needs to be killed here.  The reason is that, even though
+	 * it will kill itself when it next runs, that may be too late.  Its
+	 * stack will be freed, possibly before then, and if that happens,
+	 * we have a use-after-free situation.  So, it gets killed here
+	 * in case it has not already killed itself.
+	 */
+	prev_sched = current->thread.prev_sched;
+	if((prev_sched->exit_state == EXIT_ZOMBIE) ||
+	   (prev_sched->exit_state == EXIT_DEAD))
+		os_kill_process(prev_sched->thread.mode.tt.extern_pid, 1);
+
+	change_sig(SIGVTALRM, vtalrm);
+	change_sig(SIGALRM, alrm);
+	change_sig(SIGPROF, prof);
+
+	arch_switch();
+
+	flush_tlb_all();
+	local_irq_restore(flags);
+
+	return(current->thread.prev_sched);
+}
+
+void release_thread_tt(struct task_struct *task)
+{
+	int pid = task->thread.mode.tt.extern_pid;
+
+	if(os_getpid() != pid)
+		os_kill_process(pid, 0);
+}
+
+void exit_thread_tt(void)
+{
+	os_close_file(current->thread.mode.tt.switch_pipe[0]);
+	os_close_file(current->thread.mode.tt.switch_pipe[1]);
+}
+
+void suspend_new_thread(int fd)
+{
+	int err;
+	char c;
+
+	os_stop_process(os_getpid());
+	err = os_read_file(fd, &c, sizeof(c));
+	if(err != sizeof(c))
+		panic("read failed in suspend_new_thread, err = %d", -err);
+}
+
+void schedule_tail(task_t *prev);
+
+static void new_thread_handler(int sig)
+{
+	unsigned long disable;
+	int (*fn)(void *);
+	void *arg;
+
+	fn = current->thread.request.u.thread.proc;
+	arg = current->thread.request.u.thread.arg;
+
+	UPT_SC(&current->thread.regs.regs) = (void *) (&sig + 1);
+	disable = (1 << (SIGVTALRM - 1)) | (1 << (SIGALRM - 1)) |
+		(1 << (SIGIO - 1)) | (1 << (SIGPROF - 1));
+	SC_SIGMASK(UPT_SC(&current->thread.regs.regs)) &= ~disable;
+
+	suspend_new_thread(current->thread.mode.tt.switch_pipe[0]);
+
+	force_flush_all();
+	if(current->thread.prev_sched != NULL)
+		schedule_tail(current->thread.prev_sched);
+	current->thread.prev_sched = NULL;
+
+	init_new_thread_signals(1);
+	enable_timer();
+	free_page(current->thread.temp_stack);
+	set_cmdline("(kernel thread)");
+
+	change_sig(SIGUSR1, 1);
+	change_sig(SIGVTALRM, 1);
+	change_sig(SIGPROF, 1);
+	local_irq_enable();
+	if(!run_kernel_thread(fn, arg, &current->thread.exec_buf))
+		do_exit(0);
+
+	/* XXX No set_user_mode here because a newly execed process will
+	 * immediately segfault on its non-existent IP, coming straight back
+	 * to the signal handler, which will call set_user_mode on its way
+	 * out.  This should probably change since it's confusing.
+	 */
+}
+
+static int new_thread_proc(void *stack)
+{
+	/* local_irq_disable is needed to block out signals until this thread is
+	 * properly scheduled.  Otherwise, the tracing thread will get mighty
+	 * upset about any signals that arrive before that.
+	 * This has the complication that it sets the saved signal mask in
+	 * the sigcontext to block signals.  This gets restored when this
+	 * thread (or a descendant, since they get a copy of this sigcontext)
+	 * returns to userspace.
+	 * So, this is compensated for elsewhere.
+	 * XXX There is still a small window until local_irq_disable() actually
+	 * finishes where signals are possible - shouldn't be a problem in
+	 * practice since SIGIO hasn't been forwarded here yet, and the
+	 * local_irq_disable should finish before a SIGVTALRM has time to be
+	 * delivered.
+	 */
+
+	local_irq_disable();
+	init_new_thread_stack(stack, new_thread_handler);
+	os_usr1_process(os_getpid());
+	change_sig(SIGUSR1, 1);
+	return(0);
+}
+
+/* Signal masking - signals are blocked at the start of fork_tramp.  They
+ * are re-enabled when finish_fork_handler is entered by fork_tramp hitting
+ * itself with a SIGUSR1.  set_user_mode has to be run with SIGUSR1 off,
+ * so it is blocked before it's called.  They are re-enabled on sigreturn
+ * despite the fact that they were blocked when the SIGUSR1 was issued because
+ * copy_thread copies the parent's sigcontext, including the signal mask
+ * onto the signal frame.
+ */
+
+void finish_fork_handler(int sig)
+{
+ 	UPT_SC(&current->thread.regs.regs) = (void *) (&sig + 1);
+	suspend_new_thread(current->thread.mode.tt.switch_pipe[0]);
+
+	force_flush_all();
+	if(current->thread.prev_sched != NULL)
+		schedule_tail(current->thread.prev_sched);
+	current->thread.prev_sched = NULL;
+
+	enable_timer();
+	change_sig(SIGVTALRM, 1);
+	local_irq_enable();
+	if(current->mm != current->parent->mm)
+		protect_memory(uml_reserved, high_physmem - uml_reserved, 1, 
+			       1, 0, 1);
+	task_protections((unsigned long) current_thread);
+
+	free_page(current->thread.temp_stack);
+	local_irq_disable();
+	change_sig(SIGUSR1, 0);
+	set_user_mode(current);
+}
+
+int fork_tramp(void *stack)
+{
+	local_irq_disable();
+	arch_init_thread();
+	init_new_thread_stack(stack, finish_fork_handler);
+
+	os_usr1_process(os_getpid());
+	change_sig(SIGUSR1, 1);
+	return(0);
+}
+
+int copy_thread_tt(int nr, unsigned long clone_flags, unsigned long sp,
+		   unsigned long stack_top, struct task_struct * p, 
+		   struct pt_regs *regs)
+{
+	int (*tramp)(void *);
+	int new_pid, err;
+	unsigned long stack;
+	
+	if(current->thread.forking)
+		tramp = fork_tramp;
+	else {
+		tramp = new_thread_proc;
+		p->thread.request.u.thread = current->thread.request.u.thread;
+	}
+
+	err = os_pipe(p->thread.mode.tt.switch_pipe, 1, 1);
+	if(err < 0){
+		printk("copy_thread : pipe failed, err = %d\n", -err);
+		return(err);
+	}
+
+	stack = alloc_stack(0, 0);
+	if(stack == 0){
+		printk(KERN_ERR "copy_thread : failed to allocate "
+		       "temporary stack\n");
+		return(-ENOMEM);
+	}
+
+	clone_flags &= CLONE_VM;
+	p->thread.temp_stack = stack;
+	new_pid = start_fork_tramp(p->thread_info, stack, clone_flags, tramp);
+	if(new_pid < 0){
+		printk(KERN_ERR "copy_thread : clone failed - errno = %d\n", 
+		       -new_pid);
+		return(new_pid);
+	}
+
+	if(current->thread.forking){
+		sc_to_sc(UPT_SC(&p->thread.regs.regs), 
+			 UPT_SC(&current->thread.regs.regs));
+		SC_SET_SYSCALL_RETURN(UPT_SC(&p->thread.regs.regs), 0);
+		if(sp != 0) SC_SP(UPT_SC(&p->thread.regs.regs)) = sp;
+	}
+	p->thread.mode.tt.extern_pid = new_pid;
+
+	current->thread.request.op = OP_FORK;
+	current->thread.request.u.fork.pid = new_pid;
+	os_usr1_process(os_getpid());
+
+	/* Enable the signal and then disable it to ensure that it is handled
+	 * here, and nowhere else.
+	 */
+	change_sig(SIGUSR1, 1);
+
+	change_sig(SIGUSR1, 0);
+	err = 0;
+	return(err);
+}
+
+void reboot_tt(void)
+{
+	current->thread.request.op = OP_REBOOT;
+	os_usr1_process(os_getpid());
+	change_sig(SIGUSR1, 1);
+}
+
+void halt_tt(void)
+{
+	current->thread.request.op = OP_HALT;
+	os_usr1_process(os_getpid());
+	change_sig(SIGUSR1, 1);
+}
+
+void kill_off_processes_tt(void)
+{
+	struct task_struct *p;
+	int me;
+
+	me = os_getpid();
+        for_each_process(p){
+		if(p->thread.mode.tt.extern_pid != me) 
+			os_kill_process(p->thread.mode.tt.extern_pid, 0);
+	}
+	if(init_task.thread.mode.tt.extern_pid != me) 
+		os_kill_process(init_task.thread.mode.tt.extern_pid, 0);
+}
+
+void initial_thread_cb_tt(void (*proc)(void *), void *arg)
+{
+	if(os_getpid() == tracing_pid){
+		(*proc)(arg);
+	}
+	else {
+		current->thread.request.op = OP_CB;
+		current->thread.request.u.cb.proc = proc;
+		current->thread.request.u.cb.arg = arg;
+		os_usr1_process(os_getpid());
+		change_sig(SIGUSR1, 1);
+
+		change_sig(SIGUSR1, 0);
+	}
+}
+
+int do_proc_op(void *t, int proc_id)
+{
+	struct task_struct *task;
+	struct thread_struct *thread;
+	int op, pid;
+
+	task = t;
+	thread = &task->thread;
+	op = thread->request.op;
+	switch(op){
+	case OP_NONE:
+	case OP_TRACE_ON:
+		break;
+	case OP_EXEC:
+		pid = thread->request.u.exec.pid;
+		do_exec(thread->mode.tt.extern_pid, pid);
+		thread->mode.tt.extern_pid = pid;
+		cpu_tasks[task->thread_info->cpu].pid = pid;
+		break;
+	case OP_FORK:
+		attach_process(thread->request.u.fork.pid);
+		break;
+	case OP_CB:
+		(*thread->request.u.cb.proc)(thread->request.u.cb.arg);
+		break;
+	case OP_REBOOT:
+	case OP_HALT:
+		break;
+	default:
+		tracer_panic("Bad op in do_proc_op");
+		break;
+	}
+	thread->request.op = OP_NONE;
+	return(op);
+}
+
+void init_idle_tt(void)
+{
+	default_idle();
+}
+
+extern void start_kernel(void);
+
+static int start_kernel_proc(void *unused)
+{
+	int pid;
+
+	block_signals();
+	pid = os_getpid();
+
+	cpu_tasks[0].pid = pid;
+	cpu_tasks[0].task = current;
+#ifdef CONFIG_SMP
+ 	cpu_online_map = cpumask_of_cpu(0);
+#endif
+	if(debug) os_stop_process(pid);
+	start_kernel();
+	return(0);
+}
+
+void set_tracing(void *task, int tracing)
+{
+	((struct task_struct *) task)->thread.mode.tt.tracing = tracing;
+}
+
+int is_tracing(void *t)
+{
+	return (((struct task_struct *) t)->thread.mode.tt.tracing);
+}
+
+int set_user_mode(void *t)
+{
+	struct task_struct *task;
+
+	task = t ? t : current;
+	if(task->thread.mode.tt.tracing) 
+		return(1);
+	task->thread.request.op = OP_TRACE_ON;
+	os_usr1_process(os_getpid());
+	return(0);
+}
+
+void set_init_pid(int pid)
+{
+	int err;
+
+	init_task.thread.mode.tt.extern_pid = pid;
+	err = os_pipe(init_task.thread.mode.tt.switch_pipe, 1, 1);
+	if(err)
+		panic("Can't create switch pipe for init_task, errno = %d",
+		      -err);
+}
+
+int start_uml_tt(void)
+{
+	void *sp;
+	int pages;
+
+	pages = (1 << CONFIG_KERNEL_STACK_ORDER);
+	sp = (void *) ((unsigned long) init_task.thread_info) +
+		pages * PAGE_SIZE - sizeof(unsigned long);
+	return(tracer(start_kernel_proc, sp));
+}
+
+int external_pid_tt(struct task_struct *task)
+{
+	return(task->thread.mode.tt.extern_pid);
+}
+
+int thread_pid_tt(struct task_struct *task)
+{
+	return(task->thread.mode.tt.extern_pid);
+}
+
+int is_valid_pid(int pid)
+{
+	struct task_struct *task;
+
+        read_lock(&tasklist_lock);
+        for_each_process(task){
+                if(task->thread.mode.tt.extern_pid == pid){
+			read_unlock(&tasklist_lock);
+			return(1);
+                }
+        }
+	read_unlock(&tasklist_lock);
+	return(0);
+}
+
+/*
+ * Overrides for Emacs so that we follow Linus's tabbing style.
+ * Emacs will notice this stuff at the end of the file and automatically
+ * adjust the settings for this buffer only.  This must remain at the end
+ * of the file.
+ * ---------------------------------------------------------------------------
+ * Local variables:
+ * c-file-style: "linux"
+ * End:
+ */