SAFE public projects git trees. - safe/jmp/linux-2.6/blob - arch/um/kernel/process.c

   1 /*
   2  * Copyright (C) 2000, 2001, 2002 Jeff Dike (jdike@karaya.com)
   3  * Copyright 2003 PathScale, Inc.
   4  * Licensed under the GPL
   5  */
   6
   7 #include "linux/kernel.h"
   8 #include "linux/sched.h"
   9 #include "linux/interrupt.h"
  10 #include "linux/string.h"
  11 #include "linux/mm.h"
  12 #include "linux/slab.h"
  13 #include "linux/utsname.h"
  14 #include "linux/fs.h"
  15 #include "linux/utime.h"
  16 #include "linux/smp_lock.h"
  17 #include "linux/module.h"
  18 #include "linux/init.h"
  19 #include "linux/capability.h"
  20 #include "linux/vmalloc.h"
  21 #include "linux/spinlock.h"
  22 #include "linux/proc_fs.h"
  23 #include "linux/ptrace.h"
  24 #include "linux/random.h"
  25 #include "linux/personality.h"
  26 #include "asm/unistd.h"
  27 #include "asm/mman.h"
  28 #include "asm/segment.h"
  29 #include "asm/stat.h"
  30 #include "asm/pgtable.h"
  31 #include "asm/processor.h"
  32 #include "asm/tlbflush.h"
  33 #include "asm/uaccess.h"
  34 #include "asm/user.h"
  35 #include "kern_util.h"
  36 #include "as-layout.h"
  37 #include "kern.h"
  38 #include "signal_kern.h"
  39 #include "init.h"
  40 #include "irq_user.h"
  41 #include "mem_user.h"
  42 #include "tlb.h"
  43 #include "frame_kern.h"
  44 #include "sigcontext.h"
  45 #include "os.h"
  46 #include "skas.h"
  47
  48 /* This is a per-cpu array.  A processor only modifies its entry and it only
  49  * cares about its entry, so it's OK if another processor is modifying its
  50  * entry.
  51  */
  52 struct cpu_task cpu_tasks[NR_CPUS] = { [0 ... NR_CPUS - 1] = { -1, NULL } };
  53
  54 static inline int external_pid(struct task_struct *task)
  55 {
  56         /* FIXME: Need to look up userspace_pid by cpu */
  57         return(userspace_pid[0]);
  58 }
  59
  60 int pid_to_processor_id(int pid)
  61 {
  62         int i;
  63
  64         for(i = 0; i < ncpus; i++){
  65                 if(cpu_tasks[i].pid == pid)
  66                         return i;
  67         }
  68         return -1;
  69 }
  70
  71 void free_stack(unsigned long stack, int order)
  72 {
  73         free_pages(stack, order);
  74 }
  75
  76 unsigned long alloc_stack(int order, int atomic)
  77 {
  78         unsigned long page;
  79         gfp_t flags = GFP_KERNEL;
  80
  81         if (atomic)
  82                 flags = GFP_ATOMIC;
  83         page = __get_free_pages(flags, order);
  84         if (page == 0)
  85                 return 0;
  86
  87         return page;
  88 }
  89
  90 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
  91 {
  92         int pid;
  93
  94         current->thread.request.u.thread.proc = fn;
  95         current->thread.request.u.thread.arg = arg;
  96         pid = do_fork(CLONE_VM | CLONE_UNTRACED | flags, 0,
  97                       &current->thread.regs, 0, NULL, NULL);
  98         return pid;
  99 }
 100
 101 static inline void set_current(struct task_struct *task)
 102 {
 103         cpu_tasks[task_thread_info(task)->cpu] = ((struct cpu_task)
 104                 { external_pid(task), task });
 105 }
 106
 107 extern void arch_switch_to(struct task_struct *from, struct task_struct *to);
 108
 109 void *_switch_to(void *prev, void *next, void *last)
 110 {
 111         struct task_struct *from = prev;
 112         struct task_struct *to= next;
 113
 114         to->thread.prev_sched = from;
 115         set_current(to);
 116
 117         do {
 118                 current->thread.saved_task = NULL;
 119
 120                 /* XXX need to check runqueues[cpu].idle */
 121                 if(current->pid == 0)
 122                         switch_timers(0);
 123
 124                 switch_threads(&from->thread.switch_buf,
 125                                &to->thread.switch_buf);
 126
 127                 arch_switch_to(current->thread.prev_sched, current);
 128
 129                 if(current->pid == 0)
 130                         switch_timers(1);
 131
 132                 if(current->thread.saved_task)
 133                         show_regs(&(current->thread.regs));
 134                 next= current->thread.saved_task;
 135                 prev= current;
 136         } while(current->thread.saved_task);
 137
 138         return current->thread.prev_sched;
 139
 140 }
 141
 142 void interrupt_end(void)
 143 {
 144         if(need_resched())
 145                 schedule();
 146         if(test_tsk_thread_flag(current, TIF_SIGPENDING))
 147                 do_signal();
 148 }
 149
 150 void exit_thread(void)
 151 {
 152 }
 153
 154 void *get_current(void)
 155 {
 156         return current;
 157 }
 158
 159 extern void schedule_tail(struct task_struct *prev);
 160
 161 /* This is called magically, by its address being stuffed in a jmp_buf
 162  * and being longjmp-d to.
 163  */
 164 void new_thread_handler(void)
 165 {
 166         int (*fn)(void *), n;
 167         void *arg;
 168
 169         if(current->thread.prev_sched != NULL)
 170                 schedule_tail(current->thread.prev_sched);
 171         current->thread.prev_sched = NULL;
 172
 173         fn = current->thread.request.u.thread.proc;
 174         arg = current->thread.request.u.thread.arg;
 175
 176         /* The return value is 1 if the kernel thread execs a process,
 177          * 0 if it just exits
 178          */
 179         n = run_kernel_thread(fn, arg, &current->thread.exec_buf);
 180         if(n == 1){
 181                 /* Handle any immediate reschedules or signals */
 182                 interrupt_end();
 183                 userspace(&current->thread.regs.regs);
 184         }
 185         else do_exit(0);
 186 }
 187
 188 /* Called magically, see new_thread_handler above */
 189 void fork_handler(void)
 190 {
 191         force_flush_all();
 192         if(current->thread.prev_sched == NULL)
 193                 panic("blech");
 194
 195         schedule_tail(current->thread.prev_sched);
 196
 197         /* XXX: if interrupt_end() calls schedule, this call to
 198          * arch_switch_to isn't needed. We could want to apply this to
 199          * improve performance. -bb */
 200         arch_switch_to(current->thread.prev_sched, current);
 201
 202         current->thread.prev_sched = NULL;
 203
 204         /* Handle any immediate reschedules or signals */
 205         interrupt_end();
 206
 207         userspace(&current->thread.regs.regs);
 208 }
 209
 210 int copy_thread(int nr, unsigned long clone_flags, unsigned long sp,
 211                 unsigned long stack_top, struct task_struct * p,
 212                 struct pt_regs *regs)
 213 {
 214         void (*handler)(void);
 215         int ret = 0;
 216
 217         p->thread = (struct thread_struct) INIT_THREAD;
 218
 219         if(current->thread.forking){
 220                 memcpy(&p->thread.regs.regs, &regs->regs,
 221                        sizeof(p->thread.regs.regs));
 222                 REGS_SET_SYSCALL_RETURN(p->thread.regs.regs.regs, 0);
 223                 if(sp != 0)
 224                         REGS_SP(p->thread.regs.regs.regs) = sp;
 225
 226                 handler = fork_handler;
 227
 228                 arch_copy_thread(&current->thread.arch, &p->thread.arch);
 229         }
 230         else {
 231                 init_thread_registers(&p->thread.regs.regs);
 232                 p->thread.request.u.thread = current->thread.request.u.thread;
 233                 handler = new_thread_handler;
 234         }
 235
 236         new_thread(task_stack_page(p), &p->thread.switch_buf, handler);
 237
 238         if (current->thread.forking) {
 239                 clear_flushed_tls(p);
 240
 241                 /*
 242                  * Set a new TLS for the child thread?
 243                  */
 244                 if (clone_flags & CLONE_SETTLS)
 245                         ret = arch_copy_tls(p);
 246         }
 247
 248         return ret;
 249 }
 250
 251 void initial_thread_cb(void (*proc)(void *), void *arg)
 252 {
 253         int save_kmalloc_ok = kmalloc_ok;
 254
 255         kmalloc_ok = 0;
 256         initial_thread_cb_skas(proc, arg);
 257         kmalloc_ok = save_kmalloc_ok;
 258 }
 259
 260 void default_idle(void)
 261 {
 262         while(1){
 263                 /* endless idle loop with no priority at all */
 264
 265                 /*
 266                  * although we are an idle CPU, we do not want to
 267                  * get into the scheduler unnecessarily.
 268                  */
 269                 if(need_resched())
 270                         schedule();
 271
 272                 idle_sleep(10);
 273         }
 274 }
 275
 276 void cpu_idle(void)
 277 {
 278         cpu_tasks[current_thread->cpu].pid = os_getpid();
 279         default_idle();
 280 }
 281
 282 void *um_virt_to_phys(struct task_struct *task, unsigned long addr,
 283                       pte_t *pte_out)
 284 {
 285         pgd_t *pgd;
 286         pud_t *pud;
 287         pmd_t *pmd;
 288         pte_t *pte;
 289         pte_t ptent;
 290
 291         if(task->mm == NULL)
 292                 return ERR_PTR(-EINVAL);
 293         pgd = pgd_offset(task->mm, addr);
 294         if(!pgd_present(*pgd))
 295                 return ERR_PTR(-EINVAL);
 296
 297         pud = pud_offset(pgd, addr);
 298         if(!pud_present(*pud))
 299                 return ERR_PTR(-EINVAL);
 300
 301         pmd = pmd_offset(pud, addr);
 302         if(!pmd_present(*pmd))
 303                 return ERR_PTR(-EINVAL);
 304
 305         pte = pte_offset_kernel(pmd, addr);
 306         ptent = *pte;
 307         if(!pte_present(ptent))
 308                 return ERR_PTR(-EINVAL);
 309
 310         if(pte_out != NULL)
 311                 *pte_out = ptent;
 312         return (void *) (pte_val(ptent) & PAGE_MASK) + (addr & ~PAGE_MASK);
 313 }
 314
 315 char *current_cmd(void)
 316 {
 317 #if defined(CONFIG_SMP) || defined(CONFIG_HIGHMEM)
 318         return "(Unknown)";
 319 #else
 320         void *addr = um_virt_to_phys(current, current->mm->arg_start, NULL);
 321         return IS_ERR(addr) ? "(Unknown)": __va((unsigned long) addr);
 322 #endif
 323 }
 324
 325 void dump_thread(struct pt_regs *regs, struct user *u)
 326 {
 327 }
 328
 329 int __cant_sleep(void) {
 330         return in_atomic() || irqs_disabled() || in_interrupt();
 331         /* Is in_interrupt() really needed? */
 332 }
 333
 334 int user_context(unsigned long sp)
 335 {
 336         unsigned long stack;
 337
 338         stack = sp & (PAGE_MASK << CONFIG_KERNEL_STACK_ORDER);
 339         return stack != (unsigned long) current_thread;
 340 }
 341
 342 extern exitcall_t __uml_exitcall_begin, __uml_exitcall_end;
 343
 344 void do_uml_exitcalls(void)
 345 {
 346         exitcall_t *call;
 347
 348         call = &__uml_exitcall_end;
 349         while (--call >= &__uml_exitcall_begin)
 350                 (*call)();
 351 }
 352
 353 char *uml_strdup(char *string)
 354 {
 355         return kstrdup(string, GFP_KERNEL);
 356 }
 357
 358 int copy_to_user_proc(void __user *to, void *from, int size)
 359 {
 360         return copy_to_user(to, from, size);
 361 }
 362
 363 int copy_from_user_proc(void *to, void __user *from, int size)
 364 {
 365         return copy_from_user(to, from, size);
 366 }
 367
 368 int clear_user_proc(void __user *buf, int size)
 369 {
 370         return clear_user(buf, size);
 371 }
 372
 373 int strlen_user_proc(char __user *str)
 374 {
 375         return strlen_user(str);
 376 }
 377
 378 int smp_sigio_handler(void)
 379 {
 380 #ifdef CONFIG_SMP
 381         int cpu = current_thread->cpu;
 382         IPI_handler(cpu);
 383         if(cpu != 0)
 384                 return 1;
 385 #endif
 386         return 0;
 387 }
 388
 389 int cpu(void)
 390 {
 391         return current_thread->cpu;
 392 }
 393
 394 static atomic_t using_sysemu = ATOMIC_INIT(0);
 395 int sysemu_supported;
 396
 397 void set_using_sysemu(int value)
 398 {
 399         if (value > sysemu_supported)
 400                 return;
 401         atomic_set(&using_sysemu, value);
 402 }
 403
 404 int get_using_sysemu(void)
 405 {
 406         return atomic_read(&using_sysemu);
 407 }
 408
 409 static int proc_read_sysemu(char *buf, char **start, off_t offset, int size,int *eof, void *data)
 410 {
 411         if (snprintf(buf, size, "%d\n", get_using_sysemu()) < size) /*No overflow*/
 412                 *eof = 1;
 413
 414         return strlen(buf);
 415 }
 416
 417 static int proc_write_sysemu(struct file *file,const char __user *buf, unsigned long count,void *data)
 418 {
 419         char tmp[2];
 420
 421         if (copy_from_user(tmp, buf, 1))
 422                 return -EFAULT;
 423
 424         if (tmp[0] >= '0' && tmp[0] <= '2')
 425                 set_using_sysemu(tmp[0] - '0');
 426         return count; /*We use the first char, but pretend to write everything*/
 427 }
 428
 429 int __init make_proc_sysemu(void)
 430 {
 431         struct proc_dir_entry *ent;
 432         if (!sysemu_supported)
 433                 return 0;
 434
 435         ent = create_proc_entry("sysemu", 0600, &proc_root);
 436
 437         if (ent == NULL)
 438         {
 439                 printk(KERN_WARNING "Failed to register /proc/sysemu\n");
 440                 return 0;
 441         }
 442
 443         ent->read_proc  = proc_read_sysemu;
 444         ent->write_proc = proc_write_sysemu;
 445
 446         return 0;
 447 }
 448
 449 late_initcall(make_proc_sysemu);
 450
 451 int singlestepping(void * t)
 452 {
 453         struct task_struct *task = t ? t : current;
 454
 455         if ( ! (task->ptrace & PT_DTRACE) )
 456                 return(0);
 457
 458         if (task->thread.singlestep_syscall)
 459                 return(1);
 460
 461         return 2;
 462 }
 463
 464 /*
 465  * Only x86 and x86_64 have an arch_align_stack().
 466  * All other arches have "#define arch_align_stack(x) (x)"
 467  * in their asm/system.h
 468  * As this is included in UML from asm-um/system-generic.h,
 469  * we can use it to behave as the subarch does.
 470  */
 471 #ifndef arch_align_stack
 472 unsigned long arch_align_stack(unsigned long sp)
 473 {
 474         if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
 475                 sp -= get_random_int() % 8192;
 476         return sp & ~0xf;
 477 }
 478 #endif