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