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/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 "asm/unistd.h"
  26 #include "asm/mman.h"
  27 #include "asm/segment.h"
  28 #include "asm/stat.h"
  29 #include "asm/pgtable.h"
  30 #include "asm/processor.h"
  31 #include "asm/tlbflush.h"
  32 #include "asm/uaccess.h"
  33 #include "asm/user.h"
  34 #include "user_util.h"
  35 #include "kern_util.h"
  36 #include "kern.h"
  37 #include "signal_kern.h"
  38 #include "init.h"
  39 #include "irq_user.h"
  40 #include "mem_user.h"
  41 #include "tlb.h"
  42 #include "frame_kern.h"
  43 #include "sigcontext.h"
  44 #include "os.h"
  45 #include "mode.h"
  46 #include "mode_kern.h"
  47 #include "choose-mode.h"
  48
  49 /* This is a per-cpu array.  A processor only modifies its entry and it only
  50  * cares about its entry, so it's OK if another processor is modifying its
  51  * entry.
  52  */
  53 struct cpu_task cpu_tasks[NR_CPUS] = { [0 ... NR_CPUS - 1] = { -1, NULL } };
  54
  55 int external_pid(void *t)
  56 {
  57         struct task_struct *task = t ? t : current;
  58
  59         return(CHOOSE_MODE_PROC(external_pid_tt, external_pid_skas, task));
  60 }
  61
  62 int pid_to_processor_id(int pid)
  63 {
  64         int i;
  65
  66         for(i = 0; i < ncpus; i++){
  67                 if(cpu_tasks[i].pid == pid) return(i);
  68         }
  69         return(-1);
  70 }
  71
  72 void free_stack(unsigned long stack, int order)
  73 {
  74         free_pages(stack, order);
  75 }
  76
  77 unsigned long alloc_stack(int order, int atomic)
  78 {
  79         unsigned long page;
  80         gfp_t flags = GFP_KERNEL;
  81
  82         if (atomic)
  83                 flags = GFP_ATOMIC;
  84         page = __get_free_pages(flags, order);
  85         if(page == 0)
  86                 return(0);
  87         stack_protections(page);
  88         return(page);
  89 }
  90
  91 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
  92 {
  93         int pid;
  94
  95         current->thread.request.u.thread.proc = fn;
  96         current->thread.request.u.thread.arg = arg;
  97         pid = do_fork(CLONE_VM | CLONE_UNTRACED | flags, 0,
  98                       &current->thread.regs, 0, NULL, NULL);
  99         if(pid < 0)
 100                 panic("do_fork failed in kernel_thread, errno = %d", pid);
 101         return(pid);
 102 }
 103
 104 void set_current(void *t)
 105 {
 106         struct task_struct *task = t;
 107
 108         cpu_tasks[task_thread_info(task)->cpu] = ((struct cpu_task)
 109                 { external_pid(task), task });
 110 }
 111
 112 void *_switch_to(void *prev, void *next, void *last)
 113 {
 114         struct task_struct *from = prev;
 115         struct task_struct *to= next;
 116
 117         to->thread.prev_sched = from;
 118         set_current(to);
 119
 120         do {
 121                 current->thread.saved_task = NULL ;
 122                 CHOOSE_MODE_PROC(switch_to_tt, switch_to_skas, prev, next);
 123                 if(current->thread.saved_task)
 124                         show_regs(&(current->thread.regs));
 125                 next= current->thread.saved_task;
 126                 prev= current;
 127         } while(current->thread.saved_task);
 128
 129         return(current->thread.prev_sched);
 130
 131 }
 132
 133 void interrupt_end(void)
 134 {
 135         if(need_resched()) schedule();
 136         if(test_tsk_thread_flag(current, TIF_SIGPENDING)) do_signal();
 137 }
 138
 139 void release_thread(struct task_struct *task)
 140 {
 141         CHOOSE_MODE(release_thread_tt(task), release_thread_skas(task));
 142 }
 143
 144 void exit_thread(void)
 145 {
 146         unprotect_stack((unsigned long) current_thread);
 147 }
 148
 149 void *get_current(void)
 150 {
 151         return(current);
 152 }
 153
 154 int copy_thread(int nr, unsigned long clone_flags, unsigned long sp,
 155                 unsigned long stack_top, struct task_struct * p,
 156                 struct pt_regs *regs)
 157 {
 158         int ret;
 159
 160         p->thread = (struct thread_struct) INIT_THREAD;
 161         ret = CHOOSE_MODE_PROC(copy_thread_tt, copy_thread_skas, nr,
 162                                 clone_flags, sp, stack_top, p, regs);
 163
 164         if (ret || !current->thread.forking)
 165                 goto out;
 166
 167         clear_flushed_tls(p);
 168
 169         /*
 170          * Set a new TLS for the child thread?
 171          */
 172         if (clone_flags & CLONE_SETTLS)
 173                 ret = arch_copy_tls(p);
 174
 175 out:
 176         return ret;
 177 }
 178
 179 void initial_thread_cb(void (*proc)(void *), void *arg)
 180 {
 181         int save_kmalloc_ok = kmalloc_ok;
 182
 183         kmalloc_ok = 0;
 184         CHOOSE_MODE_PROC(initial_thread_cb_tt, initial_thread_cb_skas, proc,
 185                          arg);
 186         kmalloc_ok = save_kmalloc_ok;
 187 }
 188
 189 unsigned long stack_sp(unsigned long page)
 190 {
 191         return(page + PAGE_SIZE - sizeof(void *));
 192 }
 193
 194 int current_pid(void)
 195 {
 196         return(current->pid);
 197 }
 198
 199 void default_idle(void)
 200 {
 201         CHOOSE_MODE(uml_idle_timer(), (void) 0);
 202
 203         while(1){
 204                 /* endless idle loop with no priority at all */
 205
 206                 /*
 207                  * although we are an idle CPU, we do not want to
 208                  * get into the scheduler unnecessarily.
 209                  */
 210                 if(need_resched())
 211                         schedule();
 212
 213                 idle_sleep(10);
 214         }
 215 }
 216
 217 void cpu_idle(void)
 218 {
 219         CHOOSE_MODE(init_idle_tt(), init_idle_skas());
 220 }
 221
 222 int page_size(void)
 223 {
 224         return(PAGE_SIZE);
 225 }
 226
 227 void *um_virt_to_phys(struct task_struct *task, unsigned long addr,
 228                       pte_t *pte_out)
 229 {
 230         pgd_t *pgd;
 231         pud_t *pud;
 232         pmd_t *pmd;
 233         pte_t *pte;
 234         pte_t ptent;
 235
 236         if(task->mm == NULL)
 237                 return(ERR_PTR(-EINVAL));
 238         pgd = pgd_offset(task->mm, addr);
 239         if(!pgd_present(*pgd))
 240                 return(ERR_PTR(-EINVAL));
 241
 242         pud = pud_offset(pgd, addr);
 243         if(!pud_present(*pud))
 244                 return(ERR_PTR(-EINVAL));
 245
 246         pmd = pmd_offset(pud, addr);
 247         if(!pmd_present(*pmd))
 248                 return(ERR_PTR(-EINVAL));
 249
 250         pte = pte_offset_kernel(pmd, addr);
 251         ptent = *pte;
 252         if(!pte_present(ptent))
 253                 return(ERR_PTR(-EINVAL));
 254
 255         if(pte_out != NULL)
 256                 *pte_out = ptent;
 257         return((void *) (pte_val(ptent) & PAGE_MASK) + (addr & ~PAGE_MASK));
 258 }
 259
 260 char *current_cmd(void)
 261 {
 262 #if defined(CONFIG_SMP) || defined(CONFIG_HIGHMEM)
 263         return("(Unknown)");
 264 #else
 265         void *addr = um_virt_to_phys(current, current->mm->arg_start, NULL);
 266         return IS_ERR(addr) ? "(Unknown)": __va((unsigned long) addr);
 267 #endif
 268 }
 269
 270 void force_sigbus(void)
 271 {
 272         printk(KERN_ERR "Killing pid %d because of a lack of memory\n",
 273                current->pid);
 274         lock_kernel();
 275         sigaddset(&current->pending.signal, SIGBUS);
 276         recalc_sigpending();
 277         current->flags |= PF_SIGNALED;
 278         do_exit(SIGBUS | 0x80);
 279 }
 280
 281 void dump_thread(struct pt_regs *regs, struct user *u)
 282 {
 283 }
 284
 285 void enable_hlt(void)
 286 {
 287         panic("enable_hlt");
 288 }
 289
 290 EXPORT_SYMBOL(enable_hlt);
 291
 292 void disable_hlt(void)
 293 {
 294         panic("disable_hlt");
 295 }
 296
 297 EXPORT_SYMBOL(disable_hlt);
 298
 299 void *um_kmalloc(int size)
 300 {
 301         return kmalloc(size, GFP_KERNEL);
 302 }
 303
 304 void *um_kmalloc_atomic(int size)
 305 {
 306         return kmalloc(size, GFP_ATOMIC);
 307 }
 308
 309 void *um_vmalloc(int size)
 310 {
 311         return vmalloc(size);
 312 }
 313
 314 void *um_vmalloc_atomic(int size)
 315 {
 316         return __vmalloc(size, GFP_ATOMIC | __GFP_HIGHMEM, PAGE_KERNEL);
 317 }
 318
 319 int __cant_sleep(void) {
 320         return in_atomic() || irqs_disabled() || in_interrupt();
 321         /* Is in_interrupt() really needed? */
 322 }
 323
 324 unsigned long get_fault_addr(void)
 325 {
 326         return((unsigned long) current->thread.fault_addr);
 327 }
 328
 329 EXPORT_SYMBOL(get_fault_addr);
 330
 331 void not_implemented(void)
 332 {
 333         printk(KERN_DEBUG "Something isn't implemented in here\n");
 334 }
 335
 336 EXPORT_SYMBOL(not_implemented);
 337
 338 int user_context(unsigned long sp)
 339 {
 340         unsigned long stack;
 341
 342         stack = sp & (PAGE_MASK << CONFIG_KERNEL_STACK_ORDER);
 343         return(stack != (unsigned long) current_thread);
 344 }
 345
 346 extern exitcall_t __uml_exitcall_begin, __uml_exitcall_end;
 347
 348 void do_uml_exitcalls(void)
 349 {
 350         exitcall_t *call;
 351
 352         call = &__uml_exitcall_end;
 353         while (--call >= &__uml_exitcall_begin)
 354                 (*call)();
 355 }
 356
 357 char *uml_strdup(char *string)
 358 {
 359         return kstrdup(string, GFP_KERNEL);
 360 }
 361
 362 int copy_to_user_proc(void __user *to, void *from, int size)
 363 {
 364         return(copy_to_user(to, from, size));
 365 }
 366
 367 int copy_from_user_proc(void *to, void __user *from, int size)
 368 {
 369         return(copy_from_user(to, from, size));
 370 }
 371
 372 int clear_user_proc(void __user *buf, int size)
 373 {
 374         return(clear_user(buf, size));
 375 }
 376
 377 int strlen_user_proc(char __user *str)
 378 {
 379         return(strlen_user(str));
 380 }
 381
 382 int smp_sigio_handler(void)
 383 {
 384 #ifdef CONFIG_SMP
 385         int cpu = current_thread->cpu;
 386         IPI_handler(cpu);
 387         if(cpu != 0)
 388                 return(1);
 389 #endif
 390         return(0);
 391 }
 392
 393 int cpu(void)
 394 {
 395         return(current_thread->cpu);
 396 }
 397
 398 static atomic_t using_sysemu = ATOMIC_INIT(0);
 399 int sysemu_supported;
 400
 401 void set_using_sysemu(int value)
 402 {
 403         if (value > sysemu_supported)
 404                 return;
 405         atomic_set(&using_sysemu, value);
 406 }
 407
 408 int get_using_sysemu(void)
 409 {
 410         return atomic_read(&using_sysemu);
 411 }
 412
 413 static int proc_read_sysemu(char *buf, char **start, off_t offset, int size,int *eof, void *data)
 414 {
 415         if (snprintf(buf, size, "%d\n", get_using_sysemu()) < size) /*No overflow*/
 416                 *eof = 1;
 417
 418         return strlen(buf);
 419 }
 420
 421 static int proc_write_sysemu(struct file *file,const char __user *buf, unsigned long count,void *data)
 422 {
 423         char tmp[2];
 424
 425         if (copy_from_user(tmp, buf, 1))
 426                 return -EFAULT;
 427
 428         if (tmp[0] >= '0' && tmp[0] <= '2')
 429                 set_using_sysemu(tmp[0] - '0');
 430         return count; /*We use the first char, but pretend to write everything*/
 431 }
 432
 433 int __init make_proc_sysemu(void)
 434 {
 435         struct proc_dir_entry *ent;
 436         if (!sysemu_supported)
 437                 return 0;
 438
 439         ent = create_proc_entry("sysemu", 0600, &proc_root);
 440
 441         if (ent == NULL)
 442         {
 443                 printk(KERN_WARNING "Failed to register /proc/sysemu\n");
 444                 return(0);
 445         }
 446
 447         ent->read_proc  = proc_read_sysemu;
 448         ent->write_proc = proc_write_sysemu;
 449
 450         return 0;
 451 }
 452
 453 late_initcall(make_proc_sysemu);
 454
 455 int singlestepping(void * t)
 456 {
 457         struct task_struct *task = t ? t : current;
 458
 459         if ( ! (task->ptrace & PT_DTRACE) )
 460                 return(0);
 461
 462         if (task->thread.singlestep_syscall)
 463                 return(1);
 464
 465         return 2;
 466 }
 467
 468 /*
 469  * Only x86 and x86_64 have an arch_align_stack().
 470  * All other arches have "#define arch_align_stack(x) (x)"
 471  * in their asm/system.h
 472  * As this is included in UML from asm-um/system-generic.h,
 473  * we can use it to behave as the subarch does.
 474  */
 475 #ifndef arch_align_stack
 476 unsigned long arch_align_stack(unsigned long sp)
 477 {
 478         if (randomize_va_space)
 479                 sp -= get_random_int() % 8192;
 480         return sp & ~0xf;
 481 }
 482 #endif