uml: throw out CONFIG_MODE_TT

This patchset throws out tt mode, which has been non-functional for a while.

This is done in phases, interspersed with code cleanups on the affected files.

The removal is done as follows:
	remove all code, config options, and files which depend on
CONFIG_MODE_TT
	get rid of the CHOOSE_MODE macro, which decided whether to
call tt-mode or skas-mode code, and replace invocations with their
skas portions
	replace all now-trivial procedures with their skas equivalents

There are now a bunch of now-redundant pieces of data structures, including
mode-specific pieces of the thread structure, pt_regs, and mm_context.  These
are all replaced with their skas-specific contents.

As part of the ongoing style compliance project, I made a style pass over all
files that were changed.  There are three such patches, one for each phase,
covering the files affected by that phase but no later ones.

I noticed that we weren't freeing the LDT state associated with a process when
it exited, so that's fixed in one of the later patches.

The last patch is a tidying patch which I've had for a while, but which caused
inexplicable crashes under tt mode.  Since that is no longer a problem, this
can now go in.

This patch:

Start getting rid of tt mode support.

This patch throws out CONFIG_MODE_TT and all config options, code, and files
which depend on it.

CONFIG_MODE_SKAS is gone and everything that depends on it is included
unconditionally.

The few changed lines are in re-written Kconfig help, lines which needed
something skas-related removed from them, and a few more which weren't
strictly deletions.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 0 insertions, 461 deletions

diff --git a/arch/um/kernel/tt/process_kern.c b/arch/um/kernel/tt/process_kern.c
deleted file mode 100644
index 74347adf81bf..000000000000
--- a/arch/um/kernel/tt/process_kern.c
+++ /dev/null
@@ -1,461 +0,0 @@
-/* 
- * 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 "kern_util.h"
-#include "os.h"
-#include "kern.h"
-#include "sigcontext.h"
-#include "mem_user.h"
-#include "tlb.h"
-#include "mode.h"
-#include "mode_kern.h"
-#include "init.h"
-#include "tt.h"
-
-void switch_to_tt(void *prev, void *next)
-{
-	struct task_struct *from, *to, *prev_sched;
-	unsigned long flags;
-	int err, vtalrm, alrm, prof, cpu;
-	char c;
-
-	from = prev;
-	to = next;
-
-	cpu = task_thread_info(from)->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;
-
-	/* Notice that here we "up" the semaphore on which "to" is waiting, and
-	 * below (the read) we wait on this semaphore (which is implemented by
-	 * switch_pipe) and go sleeping. Thus, after that, we have resumed in
-	 * "to", and can't use any more the value of "from" (which is outdated),
-	 * nor the value in "to" (since it was the task which stole us the CPU,
-	 * which we don't care about). */
-
-	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);
-
-	if(from->thread.mode.tt.switch_pipe[0] == -1)
-		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->thread.mode.tt.switch_pipe[0] == -1)
-		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_to_tt(prev_sched, current);
-
-	flush_tlb_all();
-	local_irq_restore(flags);
-}
-
-void release_thread_tt(struct task_struct *task)
-{
-	int pid = task->thread.mode.tt.extern_pid;
-
-	/*
-         * We first have to kill the other process, before
-         * closing its switch_pipe. Else it might wake up
-         * and receive "EOF" before we could kill it.
-         */
-	if(os_getpid() != pid)
-		os_kill_process(pid, 0);
-
-        os_close_file(task->thread.mode.tt.switch_pipe[0]);
-        os_close_file(task->thread.mode.tt.switch_pipe[1]);
-	/* use switch_pipe as flag: thread is released */
-        task->thread.mode.tt.switch_pipe[0] = -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(struct task_struct *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();
-	enable_timer();
-	free_page(current->thread.temp_stack);
-	set_cmdline("(kernel thread)");
-
-	change_sig(SIGUSR1, 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);
-	stack_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(task_stack_page(p), 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(&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(task)->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 = task_stack_page(&init_task) +
-		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);
-}