arch/um/kernel/skas/process_kern.c

   1 /*
   2  * Copyright (C) 2002 Jeff Dike (jdike@karaya.com)
   3  * Licensed under the GPL
   4  */
   5
   6 #include "linux/sched.h"
   7 #include "linux/slab.h"
   8 #include "linux/ptrace.h"
   9 #include "linux/proc_fs.h"
  10 #include "linux/file.h"
  11 #include "linux/errno.h"
  12 #include "linux/init.h"
  13 #include "asm/uaccess.h"
  14 #include "asm/atomic.h"
  15 #include "kern_util.h"
  16 #include "skas.h"
  17 #include "os.h"
  18 #include "user_util.h"
  19 #include "tlb.h"
  20 #include "kern.h"
  21 #include "mode.h"
  22 #include "registers.h"
  23
  24 void switch_to_skas(void *prev, void *next)
  25 {
  26         struct task_struct *from, *to;
  27
  28         from = prev;
  29         to = next;
  30
  31         /* XXX need to check runqueues[cpu].idle */
  32         if(current->pid == 0)
  33                 switch_timers(0);
  34
  35         switch_threads(&from->thread.mode.skas.switch_buf,
  36                        to->thread.mode.skas.switch_buf);
  37
  38         arch_switch_to_skas(current->thread.prev_sched, current);
  39
  40         if(current->pid == 0)
  41                 switch_timers(1);
  42 }
  43
  44 extern void schedule_tail(struct task_struct *prev);
  45
  46 void new_thread_handler(int sig)
  47 {
  48         int (*fn)(void *), n;
  49         void *arg;
  50
  51         fn = current->thread.request.u.thread.proc;
  52         arg = current->thread.request.u.thread.arg;
  53         os_usr1_signal(1);
  54         thread_wait(&current->thread.mode.skas.switch_buf,
  55                     current->thread.mode.skas.fork_buf);
  56
  57         if(current->thread.prev_sched != NULL)
  58                 schedule_tail(current->thread.prev_sched);
  59         current->thread.prev_sched = NULL;
  60
  61         /* The return value is 1 if the kernel thread execs a process,
  62          * 0 if it just exits
  63          */
  64         n = run_kernel_thread(fn, arg, &current->thread.exec_buf);
  65         if(n == 1){
  66                 /* Handle any immediate reschedules or signals */
  67                 interrupt_end();
  68                 userspace(&current->thread.regs.regs);
  69         }
  70         else do_exit(0);
  71 }
  72
  73 void new_thread_proc(void *stack, void (*handler)(int sig))
  74 {
  75         init_new_thread_stack(stack, handler);
  76         os_usr1_process(os_getpid());
  77 }
  78
  79 void release_thread_skas(struct task_struct *task)
  80 {
  81 }
  82
  83 void fork_handler(int sig)
  84 {
  85         os_usr1_signal(1);
  86         thread_wait(&current->thread.mode.skas.switch_buf,
  87                     current->thread.mode.skas.fork_buf);
  88
  89         force_flush_all();
  90         if(current->thread.prev_sched == NULL)
  91                 panic("blech");
  92
  93         schedule_tail(current->thread.prev_sched);
  94
  95         /* XXX: if interrupt_end() calls schedule, this call to
  96          * arch_switch_to_skas isn't needed. We could want to apply this to
  97          * improve performance. -bb */
  98         arch_switch_to_skas(current->thread.prev_sched, current);
  99
 100         current->thread.prev_sched = NULL;
 101
 102 /* Handle any immediate reschedules or signals */
 103         interrupt_end();
 104
 105         userspace(&current->thread.regs.regs);
 106 }
 107
 108 int copy_thread_skas(int nr, unsigned long clone_flags, unsigned long sp,
 109                      unsigned long stack_top, struct task_struct * p,
 110                      struct pt_regs *regs)
 111 {
 112         void (*handler)(int);
 113
 114         if(current->thread.forking){
 115                 memcpy(&p->thread.regs.regs.skas, &regs->regs.skas,
 116                        sizeof(p->thread.regs.regs.skas));
 117                 REGS_SET_SYSCALL_RETURN(p->thread.regs.regs.skas.regs, 0);
 118                 if(sp != 0) REGS_SP(p->thread.regs.regs.skas.regs) = sp;
 119
 120                 handler = fork_handler;
 121
 122                 arch_copy_thread(&current->thread.arch, &p->thread.arch);
 123         }
 124         else {
 125                 init_thread_registers(&p->thread.regs.regs);
 126                 p->thread.request.u.thread = current->thread.request.u.thread;
 127                 handler = new_thread_handler;
 128         }
 129
 130         new_thread(task_stack_page(p), &p->thread.mode.skas.switch_buf,
 131                    &p->thread.mode.skas.fork_buf, handler);
 132         return(0);
 133 }
 134
 135 int new_mm(unsigned long stack)
 136 {
 137         int fd;
 138
 139         fd = os_open_file("/proc/mm", of_cloexec(of_write(OPENFLAGS())), 0);
 140         if(fd < 0)
 141                 return(fd);
 142
 143         if(skas_needs_stub)
 144                 map_stub_pages(fd, CONFIG_STUB_CODE, CONFIG_STUB_DATA, stack);
 145
 146         return(fd);
 147 }
 148
 149 void init_idle_skas(void)
 150 {
 151         cpu_tasks[current_thread->cpu].pid = os_getpid();
 152         default_idle();
 153 }
 154
 155 extern void start_kernel(void);
 156
 157 static int start_kernel_proc(void *unused)
 158 {
 159         int pid;
 160
 161         block_signals();
 162         pid = os_getpid();
 163
 164         cpu_tasks[0].pid = pid;
 165         cpu_tasks[0].task = current;
 166 #ifdef CONFIG_SMP
 167         cpu_online_map = cpumask_of_cpu(0);
 168 #endif
 169         start_kernel();
 170         return(0);
 171 }
 172
 173 extern int userspace_pid[];
 174
 175 int start_uml_skas(void)
 176 {
 177         if(proc_mm)
 178                 userspace_pid[0] = start_userspace(0);
 179
 180         init_new_thread_signals();
 181
 182         init_task.thread.request.u.thread.proc = start_kernel_proc;
 183         init_task.thread.request.u.thread.arg = NULL;
 184         return(start_idle_thread(task_stack_page(&init_task),
 185                                  &init_task.thread.mode.skas.switch_buf,
 186                                  &init_task.thread.mode.skas.fork_buf));
 187 }
 188
 189 int external_pid_skas(struct task_struct *task)
 190 {
 191 #warning Need to look up userspace_pid by cpu
 192         return(userspace_pid[0]);
 193 }
 194
 195 int thread_pid_skas(struct task_struct *task)
 196 {
 197 #warning Need to look up userspace_pid by cpu
 198         return(userspace_pid[0]);
 199 }
 200
 201 void kill_off_processes_skas(void)
 202 {
 203         if(proc_mm)
 204 #warning need to loop over userspace_pids in kill_off_processes_skas
 205                 os_kill_ptraced_process(userspace_pid[0], 1);
 206         else {
 207                 struct task_struct *p;
 208                 int pid, me;
 209
 210                 me = os_getpid();
 211                 for_each_process(p){
 212                         if(p->mm == NULL)
 213                                 continue;
 214
 215                         pid = p->mm->context.skas.id.u.pid;
 216                         os_kill_ptraced_process(pid, 1);
 217                 }
 218         }
 219 }
 220
 221 unsigned long current_stub_stack(void)
 222 {
 223         if(current->mm == NULL)
 224                 return(0);
 225
 226         return(current->mm->context.skas.id.stack);
 227 }