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