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 void default_idle(void)
 187 {
 188         CHOOSE_MODE(uml_idle_timer(), (void) 0);
 189
 190         while(1){
 191                 /* endless idle loop with no priority at all */
 192
 193                 /*
 194                  * although we are an idle CPU, we do not want to
 195                  * get into the scheduler unnecessarily.
 196                  */
 197                 if(need_resched())
 198                         schedule();
 199
 200                 idle_sleep(10);
 201         }
 202 }
 203
 204 void cpu_idle(void)
 205 {
 206         CHOOSE_MODE(init_idle_tt(), init_idle_skas());
 207 }
 208
 209 void *um_virt_to_phys(struct task_struct *task, unsigned long addr,
 210                       pte_t *pte_out)
 211 {
 212         pgd_t *pgd;
 213         pud_t *pud;
 214         pmd_t *pmd;
 215         pte_t *pte;
 216         pte_t ptent;
 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         ptent = *pte;
 234         if(!pte_present(ptent))
 235                 return ERR_PTR(-EINVAL);
 236
 237         if(pte_out != NULL)
 238                 *pte_out = ptent;
 239         return (void *) (pte_val(ptent) & PAGE_MASK) + (addr & ~PAGE_MASK);
 240 }
 241
 242 char *current_cmd(void)
 243 {
 244 #if defined(CONFIG_SMP) || defined(CONFIG_HIGHMEM)
 245         return "(Unknown)";
 246 #else
 247         void *addr = um_virt_to_phys(current, current->mm->arg_start, NULL);
 248         return IS_ERR(addr) ? "(Unknown)": __va((unsigned long) addr);
 249 #endif
 250 }
 251
 252 void dump_thread(struct pt_regs *regs, struct user *u)
 253 {
 254 }
 255
 256 int __cant_sleep(void) {
 257         return in_atomic() || irqs_disabled() || in_interrupt();
 258         /* Is in_interrupt() really needed? */
 259 }
 260
 261 int user_context(unsigned long sp)
 262 {
 263         unsigned long stack;
 264
 265         stack = sp & (PAGE_MASK << CONFIG_KERNEL_STACK_ORDER);
 266         return stack != (unsigned long) current_thread;
 267 }
 268
 269 extern exitcall_t __uml_exitcall_begin, __uml_exitcall_end;
 270
 271 void do_uml_exitcalls(void)
 272 {
 273         exitcall_t *call;
 274
 275         call = &__uml_exitcall_end;
 276         while (--call >= &__uml_exitcall_begin)
 277                 (*call)();
 278 }
 279
 280 char *uml_strdup(char *string)
 281 {
 282         return kstrdup(string, GFP_KERNEL);
 283 }
 284
 285 int copy_to_user_proc(void __user *to, void *from, int size)
 286 {
 287         return copy_to_user(to, from, size);
 288 }
 289
 290 int copy_from_user_proc(void *to, void __user *from, int size)
 291 {
 292         return copy_from_user(to, from, size);
 293 }
 294
 295 int clear_user_proc(void __user *buf, int size)
 296 {
 297         return clear_user(buf, size);
 298 }
 299
 300 int strlen_user_proc(char __user *str)
 301 {
 302         return strlen_user(str);
 303 }
 304
 305 int smp_sigio_handler(void)
 306 {
 307 #ifdef CONFIG_SMP
 308         int cpu = current_thread->cpu;
 309         IPI_handler(cpu);
 310         if(cpu != 0)
 311                 return 1;
 312 #endif
 313         return 0;
 314 }
 315
 316 int cpu(void)
 317 {
 318         return current_thread->cpu;
 319 }
 320
 321 static atomic_t using_sysemu = ATOMIC_INIT(0);
 322 int sysemu_supported;
 323
 324 void set_using_sysemu(int value)
 325 {
 326         if (value > sysemu_supported)
 327                 return;
 328         atomic_set(&using_sysemu, value);
 329 }
 330
 331 int get_using_sysemu(void)
 332 {
 333         return atomic_read(&using_sysemu);
 334 }
 335
 336 static int proc_read_sysemu(char *buf, char **start, off_t offset, int size,int *eof, void *data)
 337 {
 338         if (snprintf(buf, size, "%d\n", get_using_sysemu()) < size) /*No overflow*/
 339                 *eof = 1;
 340
 341         return strlen(buf);
 342 }
 343
 344 static int proc_write_sysemu(struct file *file,const char __user *buf, unsigned long count,void *data)
 345 {
 346         char tmp[2];
 347
 348         if (copy_from_user(tmp, buf, 1))
 349                 return -EFAULT;
 350
 351         if (tmp[0] >= '0' && tmp[0] <= '2')
 352                 set_using_sysemu(tmp[0] - '0');
 353         return count; /*We use the first char, but pretend to write everything*/
 354 }
 355
 356 int __init make_proc_sysemu(void)
 357 {
 358         struct proc_dir_entry *ent;
 359         if (!sysemu_supported)
 360                 return 0;
 361
 362         ent = create_proc_entry("sysemu", 0600, &proc_root);
 363
 364         if (ent == NULL)
 365         {
 366                 printk(KERN_WARNING "Failed to register /proc/sysemu\n");
 367                 return 0;
 368         }
 369
 370         ent->read_proc  = proc_read_sysemu;
 371         ent->write_proc = proc_write_sysemu;
 372
 373         return 0;
 374 }
 375
 376 late_initcall(make_proc_sysemu);
 377
 378 int singlestepping(void * t)
 379 {
 380         struct task_struct *task = t ? t : current;
 381
 382         if ( ! (task->ptrace & PT_DTRACE) )
 383                 return(0);
 384
 385         if (task->thread.singlestep_syscall)
 386                 return(1);
 387
 388         return 2;
 389 }
 390
 391 /*
 392  * Only x86 and x86_64 have an arch_align_stack().
 393  * All other arches have "#define arch_align_stack(x) (x)"
 394  * in their asm/system.h
 395  * As this is included in UML from asm-um/system-generic.h,
 396  * we can use it to behave as the subarch does.
 397  */
 398 #ifndef arch_align_stack
 399 unsigned long arch_align_stack(unsigned long sp)
 400 {
 401         if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
 402                 sp -= get_random_int() % 8192;
 403         return sp & ~0xf;
 404 }
 405 #endif