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 #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 static inline int external_pid(struct task_struct *task)
  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)
  68                         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         return pid;
 101 }
 102
 103 static inline void set_current(struct task_struct *task)
 104 {
 105         cpu_tasks[task_thread_info(task)->cpu] = ((struct cpu_task)
 106                 { external_pid(task), task });
 107 }
 108
 109 void *_switch_to(void *prev, void *next, void *last)
 110 {
 111         struct task_struct *from = prev;
 112         struct task_struct *to= next;
 113
 114         to->thread.prev_sched = from;
 115         set_current(to);
 116
 117         do {
 118                 current->thread.saved_task = NULL ;
 119                 CHOOSE_MODE_PROC(switch_to_tt, switch_to_skas, prev, next);
 120                 if(current->thread.saved_task)
 121                         show_regs(&(current->thread.regs));
 122                 next= current->thread.saved_task;
 123                 prev= current;
 124         } while(current->thread.saved_task);
 125
 126         return current->thread.prev_sched;
 127
 128 }
 129
 130 void interrupt_end(void)
 131 {
 132         if(need_resched())
 133                 schedule();
 134         if(test_tsk_thread_flag(current, TIF_SIGPENDING))
 135                 do_signal();
 136 }
 137
 138 void release_thread(struct task_struct *task)
 139 {
 140         CHOOSE_MODE(release_thread_tt(task), release_thread_skas(task));
 141 }
 142
 143 void exit_thread(void)
 144 {
 145         unprotect_stack((unsigned long) current_thread);
 146 }
 147
 148 void *get_current(void)
 149 {
 150         return current;
 151 }
 152
 153 int copy_thread(int nr, unsigned long clone_flags, unsigned long sp,
 154                 unsigned long stack_top, struct task_struct * p,
 155                 struct pt_regs *regs)
 156 {
 157         int ret;
 158
 159         p->thread = (struct thread_struct) INIT_THREAD;
 160         ret = CHOOSE_MODE_PROC(copy_thread_tt, copy_thread_skas, nr,
 161                                 clone_flags, sp, stack_top, p, regs);
 162
 163         if (ret || !current->thread.forking)
 164                 goto out;
 165
 166         clear_flushed_tls(p);
 167
 168         /*
 169          * Set a new TLS for the child thread?
 170          */
 171         if (clone_flags & CLONE_SETTLS)
 172                 ret = arch_copy_tls(p);
 173
 174 out:
 175         return ret;
 176 }
 177
 178 void initial_thread_cb(void (*proc)(void *), void *arg)
 179 {
 180         int save_kmalloc_ok = kmalloc_ok;
 181
 182         kmalloc_ok = 0;
 183         CHOOSE_MODE_PROC(initial_thread_cb_tt, initial_thread_cb_skas, proc,
 184                          arg);
 185         kmalloc_ok = save_kmalloc_ok;
 186 }
 187
 188 #ifdef CONFIG_MODE_TT
 189 unsigned long stack_sp(unsigned long page)
 190 {
 191         return page + PAGE_SIZE - sizeof(void *);
 192 }
 193 #endif
 194
 195 void default_idle(void)
 196 {
 197         CHOOSE_MODE(uml_idle_timer(), (void) 0);
 198
 199         while(1){
 200                 /* endless idle loop with no priority at all */
 201
 202                 /*
 203                  * although we are an idle CPU, we do not want to
 204                  * get into the scheduler unnecessarily.
 205                  */
 206                 if(need_resched())
 207                         schedule();
 208
 209                 idle_sleep(10);
 210         }
 211 }
 212
 213 void cpu_idle(void)
 214 {
 215         CHOOSE_MODE(init_idle_tt(), init_idle_skas());
 216 }
 217
 218 void *um_virt_to_phys(struct task_struct *task, unsigned long addr,
 219                       pte_t *pte_out)
 220 {
 221         pgd_t *pgd;
 222         pud_t *pud;
 223         pmd_t *pmd;
 224         pte_t *pte;
 225         pte_t ptent;
 226
 227         if(task->mm == NULL)
 228                 return ERR_PTR(-EINVAL);
 229         pgd = pgd_offset(task->mm, addr);
 230         if(!pgd_present(*pgd))
 231                 return ERR_PTR(-EINVAL);
 232
 233         pud = pud_offset(pgd, addr);
 234         if(!pud_present(*pud))
 235                 return ERR_PTR(-EINVAL);
 236
 237         pmd = pmd_offset(pud, addr);
 238         if(!pmd_present(*pmd))
 239                 return ERR_PTR(-EINVAL);
 240
 241         pte = pte_offset_kernel(pmd, addr);
 242         ptent = *pte;
 243         if(!pte_present(ptent))
 244                 return ERR_PTR(-EINVAL);
 245
 246         if(pte_out != NULL)
 247                 *pte_out = ptent;
 248         return (void *) (pte_val(ptent) & PAGE_MASK) + (addr & ~PAGE_MASK);
 249 }
 250
 251 char *current_cmd(void)
 252 {
 253 #if defined(CONFIG_SMP) || defined(CONFIG_HIGHMEM)
 254         return "(Unknown)";
 255 #else
 256         void *addr = um_virt_to_phys(current, current->mm->arg_start, NULL);
 257         return IS_ERR(addr) ? "(Unknown)": __va((unsigned long) addr);
 258 #endif
 259 }
 260
 261 void dump_thread(struct pt_regs *regs, struct user *u)
 262 {
 263 }
 264
 265 void *um_kmalloc(int size)
 266 {
 267         return kmalloc(size, GFP_KERNEL);
 268 }
 269
 270 void *um_kmalloc_atomic(int size)
 271 {
 272         return kmalloc(size, GFP_ATOMIC);
 273 }
 274
 275 void *um_vmalloc(int size)
 276 {
 277         return vmalloc(size);
 278 }
 279
 280 int __cant_sleep(void) {
 281         return in_atomic() || irqs_disabled() || in_interrupt();
 282         /* Is in_interrupt() really needed? */
 283 }
 284
 285 int user_context(unsigned long sp)
 286 {
 287         unsigned long stack;
 288
 289         stack = sp & (PAGE_MASK << CONFIG_KERNEL_STACK_ORDER);
 290         return stack != (unsigned long) current_thread;
 291 }
 292
 293 extern exitcall_t __uml_exitcall_begin, __uml_exitcall_end;
 294
 295 void do_uml_exitcalls(void)
 296 {
 297         exitcall_t *call;
 298
 299         call = &__uml_exitcall_end;
 300         while (--call >= &__uml_exitcall_begin)
 301                 (*call)();
 302 }
 303
 304 char *uml_strdup(char *string)
 305 {
 306         return kstrdup(string, GFP_KERNEL);
 307 }
 308
 309 int copy_to_user_proc(void __user *to, void *from, int size)
 310 {
 311         return copy_to_user(to, from, size);
 312 }
 313
 314 int copy_from_user_proc(void *to, void __user *from, int size)
 315 {
 316         return copy_from_user(to, from, size);
 317 }
 318
 319 int clear_user_proc(void __user *buf, int size)
 320 {
 321         return clear_user(buf, size);
 322 }
 323
 324 int strlen_user_proc(char __user *str)
 325 {
 326         return strlen_user(str);
 327 }
 328
 329 int smp_sigio_handler(void)
 330 {
 331 #ifdef CONFIG_SMP
 332         int cpu = current_thread->cpu;
 333         IPI_handler(cpu);
 334         if(cpu != 0)
 335                 return 1;
 336 #endif
 337         return 0;
 338 }
 339
 340 int cpu(void)
 341 {
 342         return current_thread->cpu;
 343 }
 344
 345 static atomic_t using_sysemu = ATOMIC_INIT(0);
 346 int sysemu_supported;
 347
 348 void set_using_sysemu(int value)
 349 {
 350         if (value > sysemu_supported)
 351                 return;
 352         atomic_set(&using_sysemu, value);
 353 }
 354
 355 int get_using_sysemu(void)
 356 {
 357         return atomic_read(&using_sysemu);
 358 }
 359
 360 static int proc_read_sysemu(char *buf, char **start, off_t offset, int size,int *eof, void *data)
 361 {
 362         if (snprintf(buf, size, "%d\n", get_using_sysemu()) < size) /*No overflow*/
 363                 *eof = 1;
 364
 365         return strlen(buf);
 366 }
 367
 368 static int proc_write_sysemu(struct file *file,const char __user *buf, unsigned long count,void *data)
 369 {
 370         char tmp[2];
 371
 372         if (copy_from_user(tmp, buf, 1))
 373                 return -EFAULT;
 374
 375         if (tmp[0] >= '0' && tmp[0] <= '2')
 376                 set_using_sysemu(tmp[0] - '0');
 377         return count; /*We use the first char, but pretend to write everything*/
 378 }
 379
 380 int __init make_proc_sysemu(void)
 381 {
 382         struct proc_dir_entry *ent;
 383         if (!sysemu_supported)
 384                 return 0;
 385
 386         ent = create_proc_entry("sysemu", 0600, &proc_root);
 387
 388         if (ent == NULL)
 389         {
 390                 printk(KERN_WARNING "Failed to register /proc/sysemu\n");
 391                 return 0;
 392         }
 393
 394         ent->read_proc  = proc_read_sysemu;
 395         ent->write_proc = proc_write_sysemu;
 396
 397         return 0;
 398 }
 399
 400 late_initcall(make_proc_sysemu);
 401
 402 int singlestepping(void * t)
 403 {
 404         struct task_struct *task = t ? t : current;
 405
 406         if ( ! (task->ptrace & PT_DTRACE) )
 407                 return(0);
 408
 409         if (task->thread.singlestep_syscall)
 410                 return(1);
 411
 412         return 2;
 413 }
 414
 415 /*
 416  * Only x86 and x86_64 have an arch_align_stack().
 417  * All other arches have "#define arch_align_stack(x) (x)"
 418  * in their asm/system.h
 419  * As this is included in UML from asm-um/system-generic.h,
 420  * we can use it to behave as the subarch does.
 421  */
 422 #ifndef arch_align_stack
 423 unsigned long arch_align_stack(unsigned long sp)
 424 {
 425         if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
 426                 sp -= get_random_int() % 8192;
 427         return sp & ~0xf;
 428 }
 429 #endif