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