git.oblomov.eu Git - linux-2.6/blob - 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 "kern_util.h"
  36 #include "as-layout.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 static inline int external_pid(struct task_struct *task)
  57 {
  58         return CHOOSE_MODE_PROC(external_pid_tt, external_pid_skas, task);
  59 }
  60
  61 int pid_to_processor_id(int pid)
  62 {
  63         int i;
  64
  65         for(i = 0; i < ncpus; i++){
  66                 if(cpu_tasks[i].pid == pid)
  67                         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
  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         return pid;
 100 }
 101
 102 static inline void set_current(struct task_struct *task)
 103 {
 104         cpu_tasks[task_thread_info(task)->cpu] = ((struct cpu_task)
 105                 { external_pid(task), task });
 106 }
 107
 108 void *_switch_to(void *prev, void *next, void *last)
 109 {
 110         struct task_struct *from = prev;
 111         struct task_struct *to= next;
 112
 113         to->thread.prev_sched = from;
 114         set_current(to);
 115
 116         do {
 117                 current->thread.saved_task = NULL ;
 118                 CHOOSE_MODE_PROC(switch_to_tt, switch_to_skas, prev, next);
 119                 if(current->thread.saved_task)
 120                         show_regs(&(current->thread.regs));
 121                 next= current->thread.saved_task;
 122                 prev= current;
 123         } while(current->thread.saved_task);
 124
 125         return current->thread.prev_sched;
 126
 127 }
 128
 129 void interrupt_end(void)
 130 {
 131         if(need_resched())
 132                 schedule();
 133         if(test_tsk_thread_flag(current, TIF_SIGPENDING))
 134                 do_signal();
 135 }
 136
 137 void release_thread(struct task_struct *task)
 138 {
 139         CHOOSE_MODE(release_thread_tt(task), release_thread_skas(task));
 140 }
 141
 142 void exit_thread(void)
 143 {
 144 }
 145
 146 void *get_current(void)
 147 {
 148         return current;
 149 }
 150
 151 int copy_thread(int nr, unsigned long clone_flags, unsigned long sp,
 152                 unsigned long stack_top, struct task_struct * p,
 153                 struct pt_regs *regs)
 154 {
 155         int ret;
 156
 157         p->thread = (struct thread_struct) INIT_THREAD;
 158         ret = CHOOSE_MODE_PROC(copy_thread_tt, copy_thread_skas, nr,
 159                                 clone_flags, sp, stack_top, p, regs);
 160
 161         if (ret || !current->thread.forking)
 162                 goto out;
 163
 164         clear_flushed_tls(p);
 165
 166         /*
 167          * Set a new TLS for the child thread?
 168          */
 169         if (clone_flags & CLONE_SETTLS)
 170                 ret = arch_copy_tls(p);
 171
 172 out:
 173         return ret;
 174 }
 175
 176 void initial_thread_cb(void (*proc)(void *), void *arg)
 177 {
 178         int save_kmalloc_ok = kmalloc_ok;
 179
 180         kmalloc_ok = 0;
 181         CHOOSE_MODE_PROC(initial_thread_cb_tt, initial_thread_cb_skas, proc,
 182                          arg);
 183         kmalloc_ok = save_kmalloc_ok;
 184 }
 185
 186 #ifdef CONFIG_MODE_TT
 187 unsigned long stack_sp(unsigned long page)
 188 {
 189         return page + PAGE_SIZE - sizeof(void *);
 190 }
 191 #endif
 192
 193 void default_idle(void)
 194 {
 195         CHOOSE_MODE(uml_idle_timer(), (void) 0);
 196
 197         while(1){
 198                 /* endless idle loop with no priority at all */
 199
 200                 /*
 201                  * although we are an idle CPU, we do not want to
 202                  * get into the scheduler unnecessarily.
 203                  */
 204                 if(need_resched())
 205                         schedule();
 206
 207                 idle_sleep(10);
 208         }
 209 }
 210
 211 void cpu_idle(void)
 212 {
 213         CHOOSE_MODE(init_idle_tt(), init_idle_skas());
 214 }
 215
 216 void *um_virt_to_phys(struct task_struct *task, unsigned long addr,
 217                       pte_t *pte_out)
 218 {
 219         pgd_t *pgd;
 220         pud_t *pud;
 221         pmd_t *pmd;
 222         pte_t *pte;
 223         pte_t ptent;
 224
 225         if(task->mm == NULL)
 226                 return ERR_PTR(-EINVAL);
 227         pgd = pgd_offset(task->mm, addr);
 228         if(!pgd_present(*pgd))
 229                 return ERR_PTR(-EINVAL);
 230
 231         pud = pud_offset(pgd, addr);
 232         if(!pud_present(*pud))
 233                 return ERR_PTR(-EINVAL);
 234
 235         pmd = pmd_offset(pud, addr);
 236         if(!pmd_present(*pmd))
 237                 return ERR_PTR(-EINVAL);
 238
 239         pte = pte_offset_kernel(pmd, addr);
 240         ptent = *pte;
 241         if(!pte_present(ptent))
 242                 return ERR_PTR(-EINVAL);
 243
 244         if(pte_out != NULL)
 245                 *pte_out = ptent;
 246         return (void *) (pte_val(ptent) & PAGE_MASK) + (addr & ~PAGE_MASK);
 247 }
 248
 249 char *current_cmd(void)
 250 {
 251 #if defined(CONFIG_SMP) || defined(CONFIG_HIGHMEM)
 252         return "(Unknown)";
 253 #else
 254         void *addr = um_virt_to_phys(current, current->mm->arg_start, NULL);
 255         return IS_ERR(addr) ? "(Unknown)": __va((unsigned long) addr);
 256 #endif
 257 }
 258
 259 void dump_thread(struct pt_regs *regs, struct user *u)
 260 {
 261 }
 262
 263 int __cant_sleep(void) {
 264         return in_atomic() || irqs_disabled() || in_interrupt();
 265         /* Is in_interrupt() really needed? */
 266 }
 267
 268 int user_context(unsigned long sp)
 269 {
 270         unsigned long stack;
 271
 272         stack = sp & (PAGE_MASK << CONFIG_KERNEL_STACK_ORDER);
 273         return stack != (unsigned long) current_thread;
 274 }
 275
 276 extern exitcall_t __uml_exitcall_begin, __uml_exitcall_end;
 277
 278 void do_uml_exitcalls(void)
 279 {
 280         exitcall_t *call;
 281
 282         call = &__uml_exitcall_end;
 283         while (--call >= &__uml_exitcall_begin)
 284                 (*call)();
 285 }
 286
 287 char *uml_strdup(char *string)
 288 {
 289         return kstrdup(string, GFP_KERNEL);
 290 }
 291
 292 int copy_to_user_proc(void __user *to, void *from, int size)
 293 {
 294         return copy_to_user(to, from, size);
 295 }
 296
 297 int copy_from_user_proc(void *to, void __user *from, int size)
 298 {
 299         return copy_from_user(to, from, size);
 300 }
 301
 302 int clear_user_proc(void __user *buf, int size)
 303 {
 304         return clear_user(buf, size);
 305 }
 306
 307 int strlen_user_proc(char __user *str)
 308 {
 309         return strlen_user(str);
 310 }
 311
 312 int smp_sigio_handler(void)
 313 {
 314 #ifdef CONFIG_SMP
 315         int cpu = current_thread->cpu;
 316         IPI_handler(cpu);
 317         if(cpu != 0)
 318                 return 1;
 319 #endif
 320         return 0;
 321 }
 322
 323 int cpu(void)
 324 {
 325         return current_thread->cpu;
 326 }
 327
 328 static atomic_t using_sysemu = ATOMIC_INIT(0);
 329 int sysemu_supported;
 330
 331 void set_using_sysemu(int value)
 332 {
 333         if (value > sysemu_supported)
 334                 return;
 335         atomic_set(&using_sysemu, value);
 336 }
 337
 338 int get_using_sysemu(void)
 339 {
 340         return atomic_read(&using_sysemu);
 341 }
 342
 343 static int proc_read_sysemu(char *buf, char **start, off_t offset, int size,int *eof, void *data)
 344 {
 345         if (snprintf(buf, size, "%d\n", get_using_sysemu()) < size) /*No overflow*/
 346                 *eof = 1;
 347
 348         return strlen(buf);
 349 }
 350
 351 static int proc_write_sysemu(struct file *file,const char __user *buf, unsigned long count,void *data)
 352 {
 353         char tmp[2];
 354
 355         if (copy_from_user(tmp, buf, 1))
 356                 return -EFAULT;
 357
 358         if (tmp[0] >= '0' && tmp[0] <= '2')
 359                 set_using_sysemu(tmp[0] - '0');
 360         return count; /*We use the first char, but pretend to write everything*/
 361 }
 362
 363 int __init make_proc_sysemu(void)
 364 {
 365         struct proc_dir_entry *ent;
 366         if (!sysemu_supported)
 367                 return 0;
 368
 369         ent = create_proc_entry("sysemu", 0600, &proc_root);
 370
 371         if (ent == NULL)
 372         {
 373                 printk(KERN_WARNING "Failed to register /proc/sysemu\n");
 374                 return 0;
 375         }
 376
 377         ent->read_proc  = proc_read_sysemu;
 378         ent->write_proc = proc_write_sysemu;
 379
 380         return 0;
 381 }
 382
 383 late_initcall(make_proc_sysemu);
 384
 385 int singlestepping(void * t)
 386 {
 387         struct task_struct *task = t ? t : current;
 388
 389         if ( ! (task->ptrace & PT_DTRACE) )
 390                 return(0);
 391
 392         if (task->thread.singlestep_syscall)
 393                 return(1);
 394
 395         return 2;
 396 }
 397
 398 /*
 399  * Only x86 and x86_64 have an arch_align_stack().
 400  * All other arches have "#define arch_align_stack(x) (x)"
 401  * in their asm/system.h
 402  * As this is included in UML from asm-um/system-generic.h,
 403  * we can use it to behave as the subarch does.
 404  */
 405 #ifndef arch_align_stack
 406 unsigned long arch_align_stack(unsigned long sp)
 407 {
 408         if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
 409                 sp -= get_random_int() % 8192;
 410         return sp & ~0xf;
 411 }
 412 #endif