arch/um/kernel/skas/process.c

   1 /*
   2  * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
   3  * Licensed under the GPL
   4  */
   5
   6 #include "linux/init.h"
   7 #include "linux/sched.h"
   8 #include "as-layout.h"
   9 #include "kern.h"
  10 #include "os.h"
  11 #include "skas.h"
  12
  13 int new_mm(unsigned long stack)
  14 {
  15         int fd, err;
  16
  17         fd = os_open_file("/proc/mm", of_cloexec(of_write(OPENFLAGS())), 0);
  18         if (fd < 0)
  19                 return fd;
  20
  21         if (skas_needs_stub) {
  22                 err = map_stub_pages(fd, STUB_CODE, STUB_DATA, stack);
  23                 if (err) {
  24                         os_close_file(fd);
  25                         return err;
  26                 }
  27         }
  28
  29         return fd;
  30 }
  31
  32 extern void start_kernel(void);
  33
  34 static int __init start_kernel_proc(void *unused)
  35 {
  36         int pid;
  37
  38         block_signals();
  39         pid = os_getpid();
  40
  41         cpu_tasks[0].pid = pid;
  42         cpu_tasks[0].task = current;
  43 #ifdef CONFIG_SMP
  44         cpu_online_map = cpumask_of_cpu(0);
  45 #endif
  46         start_kernel();
  47         return 0;
  48 }
  49
  50 extern int userspace_pid[];
  51
  52 extern char cpu0_irqstack[];
  53
  54 int __init start_uml(void)
  55 {
  56         stack_protections((unsigned long) &cpu0_irqstack);
  57         set_sigstack(cpu0_irqstack, THREAD_SIZE);
  58         if (proc_mm) {
  59                 userspace_pid[0] = start_userspace(0);
  60                 if (userspace_pid[0] < 0) {
  61                         printf("start_uml - start_userspace returned %d\n",
  62                                userspace_pid[0]);
  63                         exit(1);
  64                 }
  65         }
  66
  67         init_new_thread_signals();
  68
  69         init_task.thread.request.u.thread.proc = start_kernel_proc;
  70         init_task.thread.request.u.thread.arg = NULL;
  71         return start_idle_thread(task_stack_page(&init_task),
  72                                  &init_task.thread.switch_buf);
  73 }
  74
  75 unsigned long current_stub_stack(void)
  76 {
  77         if (current->mm == NULL)
  78                 return 0;
  79
  80         return current->mm->context.id.stack;
  81 }