-/*
- * 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- * "to", and can't use any more the value of "from" (which is outdated),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(¤t->thread.regs.regs) = (void *) (&sig + 1);
- disable = (1 << (SIGVTALRM - 1)) | (1 << (SIGALRM - 1)) |
- (1 << (SIGIO - 1)) | (1 << (SIGPROF - 1));
- SC_SIGMASK(UPT_SC(¤t->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, ¤t->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(¤t->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(®s->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);
-}
projects / deliverable / linux.git / commitdiff
