arch/um/kernel/process_kern.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/config.h"
   8 #include "linux/kernel.h"
   9 #include "linux/sched.h"
  10 #include "linux/interrupt.h"
  11 #include "linux/string.h"
  12 #include "linux/mm.h"
  13 #include "linux/slab.h"
  14 #include "linux/utsname.h"
  15 #include "linux/fs.h"
  16 #include "linux/utime.h"
  17 #include "linux/smp_lock.h"
  18 #include "linux/module.h"
  19 #include "linux/init.h"
  20 #include "linux/capability.h"
  21 #include "linux/vmalloc.h"
  22 #include "linux/spinlock.h"
  23 #include "linux/proc_fs.h"
  24 #include "linux/ptrace.h"
  25 #include "linux/random.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 "user_util.h"
  36 #include "kern_util.h"
  37 #include "kern.h"
  38 #include "signal_kern.h"
  39 #include "signal_user.h"
  40 #include "init.h"
  41 #include "irq_user.h"
  42 #include "mem_user.h"
  43 #include "time_user.h"
  44 #include "tlb.h"
  45 #include "frame_kern.h"
  46 #include "sigcontext.h"
  47 #include "os.h"
  48 #include "mode.h"
  49 #include "mode_kern.h"
  50 #include "choose-mode.h"
  51
  52 /* This is a per-cpu array.  A processor only modifies its entry and it only
  53  * cares about its entry, so it's OK if another processor is modifying its
  54  * entry.
  55  */
  56 struct cpu_task cpu_tasks[NR_CPUS] = { [0 ... NR_CPUS - 1] = { -1, NULL } };
  57
  58 int external_pid(void *t)
  59 {
  60         struct task_struct *task = t ? t : current;
  61
  62         return(CHOOSE_MODE_PROC(external_pid_tt, external_pid_skas, task));
  63 }
  64
  65 int pid_to_processor_id(int pid)
  66 {
  67         int i;
  68
  69         for(i = 0; i < ncpus; i++){
  70                 if(cpu_tasks[i].pid == pid) return(i);
  71         }
  72         return(-1);
  73 }
  74
  75 void free_stack(unsigned long stack, int order)
  76 {
  77         free_pages(stack, order);
  78 }
  79
  80 unsigned long alloc_stack(int order, int atomic)
  81 {
  82         unsigned long page;
  83         gfp_t flags = GFP_KERNEL;
  84
  85         if (atomic)
  86                 flags = GFP_ATOMIC;
  87         page = __get_free_pages(flags, order);
  88         if(page == 0)
  89                 return(0);
  90         stack_protections(page);
  91         return(page);
  92 }
  93
  94 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
  95 {
  96         int pid;
  97
  98         current->thread.request.u.thread.proc = fn;
  99         current->thread.request.u.thread.arg = arg;
 100         pid = do_fork(CLONE_VM | CLONE_UNTRACED | flags, 0,
 101                       &current->thread.regs, 0, NULL, NULL);
 102         if(pid < 0)
 103                 panic("do_fork failed in kernel_thread, errno = %d", pid);
 104         return(pid);
 105 }
 106
 107 void set_current(void *t)
 108 {
 109         struct task_struct *task = t;
 110
 111         cpu_tasks[task->thread_info->cpu] = ((struct cpu_task)
 112                 { external_pid(task), task });
 113 }
 114
 115 void *_switch_to(void *prev, void *next, void *last)
 116 {
 117         struct task_struct *from = prev;
 118         struct task_struct *to= next;
 119
 120         to->thread.prev_sched = from;
 121         set_current(to);
 122
 123         do {
 124                 current->thread.saved_task = NULL ;
 125                 CHOOSE_MODE_PROC(switch_to_tt, switch_to_skas, prev, next);
 126                 if(current->thread.saved_task)
 127                         show_regs(&(current->thread.regs));
 128                 next= current->thread.saved_task;
 129                 prev= current;
 130         } while(current->thread.saved_task);
 131
 132         return(current->thread.prev_sched);
 133
 134 }
 135
 136 void interrupt_end(void)
 137 {
 138         if(need_resched()) schedule();
 139         if(test_tsk_thread_flag(current, TIF_SIGPENDING)) do_signal();
 140 }
 141
 142 void release_thread(struct task_struct *task)
 143 {
 144         CHOOSE_MODE(release_thread_tt(task), release_thread_skas(task));
 145 }
 146
 147 void exit_thread(void)
 148 {
 149         unprotect_stack((unsigned long) current_thread);
 150 }
 151
 152 void *get_current(void)
 153 {
 154         return(current);
 155 }
 156
 157 int copy_thread(int nr, unsigned long clone_flags, unsigned long sp,
 158                 unsigned long stack_top, struct task_struct * p,
 159                 struct pt_regs *regs)
 160 {
 161         p->thread = (struct thread_struct) INIT_THREAD;
 162         return(CHOOSE_MODE_PROC(copy_thread_tt, copy_thread_skas, nr,
 163                                 clone_flags, sp, stack_top, p, regs));
 164 }
 165
 166 void initial_thread_cb(void (*proc)(void *), void *arg)
 167 {
 168         int save_kmalloc_ok = kmalloc_ok;
 169
 170         kmalloc_ok = 0;
 171         CHOOSE_MODE_PROC(initial_thread_cb_tt, initial_thread_cb_skas, proc,
 172                          arg);
 173         kmalloc_ok = save_kmalloc_ok;
 174 }
 175
 176 unsigned long stack_sp(unsigned long page)
 177 {
 178         return(page + PAGE_SIZE - sizeof(void *));
 179 }
 180
 181 int current_pid(void)
 182 {
 183         return(current->pid);
 184 }
 185
 186 void default_idle(void)
 187 {
 188         CHOOSE_MODE(uml_idle_timer(), (void) 0);
 189
 190         atomic_inc(&init_mm.mm_count);
 191         current->mm = &init_mm;
 192         current->active_mm = &init_mm;
 193
 194         while(1){
 195                 /* endless idle loop with no priority at all */
 196
 197                 /*
 198                  * although we are an idle CPU, we do not want to
 199                  * get into the scheduler unnecessarily.
 200                  */
 201                 if(need_resched())
 202                         schedule();
 203
 204                 idle_sleep(10);
 205         }
 206 }
 207
 208 void cpu_idle(void)
 209 {
 210         CHOOSE_MODE(init_idle_tt(), init_idle_skas());
 211 }
 212
 213 int page_size(void)
 214 {
 215         return(PAGE_SIZE);
 216 }
 217
 218 void *um_virt_to_phys(struct task_struct *task, unsigned long addr,
 219                       pte_t *pte_out)
 220 {
 221         pgd_t *pgd;
 222         pud_t *pud;
 223         pmd_t *pmd;
 224         pte_t *pte;
 225         pte_t ptent;
 226
 227         if(task->mm == NULL)
 228                 return(ERR_PTR(-EINVAL));
 229         pgd = pgd_offset(task->mm, addr);
 230         if(!pgd_present(*pgd))
 231                 return(ERR_PTR(-EINVAL));
 232
 233         pud = pud_offset(pgd, addr);
 234         if(!pud_present(*pud))
 235                 return(ERR_PTR(-EINVAL));
 236
 237         pmd = pmd_offset(pud, addr);
 238         if(!pmd_present(*pmd))
 239                 return(ERR_PTR(-EINVAL));
 240
 241         pte = pte_offset_kernel(pmd, addr);
 242         ptent = *pte;
 243         if(!pte_present(ptent))
 244                 return(ERR_PTR(-EINVAL));
 245
 246         if(pte_out != NULL)
 247                 *pte_out = ptent;
 248         return((void *) (pte_val(ptent) & PAGE_MASK) + (addr & ~PAGE_MASK));
 249 }
 250
 251 char *current_cmd(void)
 252 {
 253 #if defined(CONFIG_SMP) || defined(CONFIG_HIGHMEM)
 254         return("(Unknown)");
 255 #else
 256         void *addr = um_virt_to_phys(current, current->mm->arg_start, NULL);
 257         return IS_ERR(addr) ? "(Unknown)": __va((unsigned long) addr);
 258 #endif
 259 }
 260
 261 void force_sigbus(void)
 262 {
 263         printk(KERN_ERR "Killing pid %d because of a lack of memory\n",
 264                current->pid);
 265         lock_kernel();
 266         sigaddset(&current->pending.signal, SIGBUS);
 267         recalc_sigpending();
 268         current->flags |= PF_SIGNALED;
 269         do_exit(SIGBUS | 0x80);
 270 }
 271
 272 void dump_thread(struct pt_regs *regs, struct user *u)
 273 {
 274 }
 275
 276 void enable_hlt(void)
 277 {
 278         panic("enable_hlt");
 279 }
 280
 281 EXPORT_SYMBOL(enable_hlt);
 282
 283 void disable_hlt(void)
 284 {
 285         panic("disable_hlt");
 286 }
 287
 288 EXPORT_SYMBOL(disable_hlt);
 289
 290 void *um_kmalloc(int size)
 291 {
 292         return(kmalloc(size, GFP_KERNEL));
 293 }
 294
 295 void *um_kmalloc_atomic(int size)
 296 {
 297         return(kmalloc(size, GFP_ATOMIC));
 298 }
 299
 300 void *um_vmalloc(int size)
 301 {
 302         return(vmalloc(size));
 303 }
 304
 305 unsigned long get_fault_addr(void)
 306 {
 307         return((unsigned long) current->thread.fault_addr);
 308 }
 309
 310 EXPORT_SYMBOL(get_fault_addr);
 311
 312 void not_implemented(void)
 313 {
 314         printk(KERN_DEBUG "Something isn't implemented in here\n");
 315 }
 316
 317 EXPORT_SYMBOL(not_implemented);
 318
 319 int user_context(unsigned long sp)
 320 {
 321         unsigned long stack;
 322
 323         stack = sp & (PAGE_MASK << CONFIG_KERNEL_STACK_ORDER);
 324         return(stack != (unsigned long) current_thread);
 325 }
 326
 327 extern exitcall_t __uml_exitcall_begin, __uml_exitcall_end;
 328
 329 void do_uml_exitcalls(void)
 330 {
 331         exitcall_t *call;
 332
 333         call = &__uml_exitcall_end;
 334         while (--call >= &__uml_exitcall_begin)
 335                 (*call)();
 336 }
 337
 338 char *uml_strdup(char *string)
 339 {
 340         return kstrdup(string, GFP_KERNEL);
 341 }
 342
 343 int copy_to_user_proc(void __user *to, void *from, int size)
 344 {
 345         return(copy_to_user(to, from, size));
 346 }
 347
 348 int copy_from_user_proc(void *to, void __user *from, int size)
 349 {
 350         return(copy_from_user(to, from, size));
 351 }
 352
 353 int clear_user_proc(void __user *buf, int size)
 354 {
 355         return(clear_user(buf, size));
 356 }
 357
 358 int strlen_user_proc(char __user *str)
 359 {
 360         return(strlen_user(str));
 361 }
 362
 363 int smp_sigio_handler(void)
 364 {
 365 #ifdef CONFIG_SMP
 366         int cpu = current_thread->cpu;
 367         IPI_handler(cpu);
 368         if(cpu != 0)
 369                 return(1);
 370 #endif
 371         return(0);
 372 }
 373
 374 int um_in_interrupt(void)
 375 {
 376         return(in_interrupt());
 377 }
 378
 379 int cpu(void)
 380 {
 381         return(current_thread->cpu);
 382 }
 383
 384 static atomic_t using_sysemu = ATOMIC_INIT(0);
 385 int sysemu_supported;
 386
 387 void set_using_sysemu(int value)
 388 {
 389         if (value > sysemu_supported)
 390                 return;
 391         atomic_set(&using_sysemu, value);
 392 }
 393
 394 int get_using_sysemu(void)
 395 {
 396         return atomic_read(&using_sysemu);
 397 }
 398
 399 static int proc_read_sysemu(char *buf, char **start, off_t offset, int size,int *eof, void *data)
 400 {
 401         if (snprintf(buf, size, "%d\n", get_using_sysemu()) < size) /*No overflow*/
 402                 *eof = 1;
 403
 404         return strlen(buf);
 405 }
 406
 407 static int proc_write_sysemu(struct file *file,const char *buf, unsigned long count,void *data)
 408 {
 409         char tmp[2];
 410
 411         if (copy_from_user(tmp, buf, 1))
 412                 return -EFAULT;
 413
 414         if (tmp[0] >= '0' && tmp[0] <= '2')
 415                 set_using_sysemu(tmp[0] - '0');
 416         return count; /*We use the first char, but pretend to write everything*/
 417 }
 418
 419 int __init make_proc_sysemu(void)
 420 {
 421         struct proc_dir_entry *ent;
 422         if (!sysemu_supported)
 423                 return 0;
 424
 425         ent = create_proc_entry("sysemu", 0600, &proc_root);
 426
 427         if (ent == NULL)
 428         {
 429                 printk(KERN_WARNING "Failed to register /proc/sysemu\n");
 430                 return(0);
 431         }
 432
 433         ent->read_proc  = proc_read_sysemu;
 434         ent->write_proc = proc_write_sysemu;
 435
 436         return 0;
 437 }
 438
 439 late_initcall(make_proc_sysemu);
 440
 441 int singlestepping(void * t)
 442 {
 443         struct task_struct *task = t ? t : current;
 444
 445         if ( ! (task->ptrace & PT_DTRACE) )
 446                 return(0);
 447
 448         if (task->thread.singlestep_syscall)
 449                 return(1);
 450
 451         return 2;
 452 }
 453
 454 /*
 455  * Only x86 and x86_64 have an arch_align_stack().
 456  * All other arches have "#define arch_align_stack(x) (x)"
 457  * in their asm/system.h
 458  * As this is included in UML from asm-um/system-generic.h,
 459  * we can use it to behave as the subarch does.
 460  */
 461 #ifndef arch_align_stack
 462 unsigned long arch_align_stack(unsigned long sp)
 463 {
 464         if (randomize_va_space)
 465                 sp -= get_random_int() % 8192;
 466         return sp & ~0xf;
 467 }
 468 #endif