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   1 /*  linux/arch/sparc/kernel/process.c
   2  *
   3  *  Copyright (C) 1995 David S. Miller (davem@davemloft.net)
   4  *  Copyright (C) 1996 Eddie C. Dost   (ecd@skynet.be)
   5  */
   6
   7 /*
   8  * This file handles the architecture-dependent parts of process handling..
   9  */
  10
  11 #include <stdarg.h>
  12
  13 #include <linux/errno.h>
  14 #include <linux/module.h>
  15 #include <linux/sched.h>
  16 #include <linux/kernel.h>
  17 #include <linux/kallsyms.h>
  18 #include <linux/mm.h>
  19 #include <linux/stddef.h>
  20 #include <linux/ptrace.h>
  21 #include <linux/slab.h>
  22 #include <linux/user.h>
  23 #include <linux/smp.h>
  24 #include <linux/reboot.h>
  25 #include <linux/delay.h>
  26 #include <linux/pm.h>
  27 #include <linux/init.h>
  28
  29 #include <asm/auxio.h>
  30 #include <asm/oplib.h>
  31 #include <asm/uaccess.h>
  32 #include <asm/system.h>
  33 #include <asm/page.h>
  34 #include <asm/pgalloc.h>
  35 #include <asm/pgtable.h>
  36 #include <asm/delay.h>
  37 #include <asm/processor.h>
  38 #include <asm/psr.h>
  39 #include <asm/elf.h>
  40 #include <asm/prom.h>
  41 #include <asm/unistd.h>
  42
  43 /*
  44  * Power management idle function
  45  * Set in pm platform drivers (apc.c and pmc.c)
  46  */
  47 void (*pm_idle)(void);
  48
  49 /*
  50  * Power-off handler instantiation for pm.h compliance
  51  * This is done via auxio, but could be used as a fallback
  52  * handler when auxio is not present-- unused for now...
  53  */
  54 void (*pm_power_off)(void) = machine_power_off;
  55 EXPORT_SYMBOL(pm_power_off);
  56
  57 /*
  58  * sysctl - toggle power-off restriction for serial console
  59  * systems in machine_power_off()
  60  */
  61 int scons_pwroff = 1;
  62
  63 extern void fpsave(unsigned long *, unsigned long *, void *, unsigned long *);
  64
  65 struct task_struct *last_task_used_math = NULL;
  66 struct thread_info *current_set[NR_CPUS];
  67
  68 #ifndef CONFIG_SMP
  69
  70 #define SUN4C_FAULT_HIGH 100
  71
  72 /*
  73  * the idle loop on a Sparc... ;)
  74  */
  75 void cpu_idle(void)
  76 {
  77         /* endless idle loop with no priority at all */
  78         for (;;) {
  79                 if (ARCH_SUN4C_SUN4) {
  80                         static int count = HZ;
  81                         static unsigned long last_jiffies;
  82                         static unsigned long last_faults;
  83                         static unsigned long fps;
  84                         unsigned long now;
  85                         unsigned long faults;
  86
  87                         extern unsigned long sun4c_kernel_faults;
  88                         extern void sun4c_grow_kernel_ring(void);
  89
  90                         local_irq_disable();
  91                         now = jiffies;
  92                         count -= (now - last_jiffies);
  93                         last_jiffies = now;
  94                         if (count < 0) {
  95                                 count += HZ;
  96                                 faults = sun4c_kernel_faults;
  97                                 fps = (fps + (faults - last_faults)) >> 1;
  98                                 last_faults = faults;
  99 #if 0
 100                                 printk("kernel faults / second = %ld\n", fps);
 101 #endif
 102                                 if (fps >= SUN4C_FAULT_HIGH) {
 103                                         sun4c_grow_kernel_ring();
 104                                 }
 105                         }
 106                         local_irq_enable();
 107                 }
 108
 109                 if (pm_idle) {
 110                         while (!need_resched())
 111                                 (*pm_idle)();
 112                 } else {
 113                         while (!need_resched())
 114                                 cpu_relax();
 115                 }
 116                 preempt_enable_no_resched();
 117                 schedule();
 118                 preempt_disable();
 119                 check_pgt_cache();
 120         }
 121 }
 122
 123 #else
 124
 125 /* This is being executed in task 0 'user space'. */
 126 void cpu_idle(void)
 127 {
 128         set_thread_flag(TIF_POLLING_NRFLAG);
 129         /* endless idle loop with no priority at all */
 130         while(1) {
 131                 while (!need_resched())
 132                         cpu_relax();
 133                 preempt_enable_no_resched();
 134                 schedule();
 135                 preempt_disable();
 136                 check_pgt_cache();
 137         }
 138 }
 139
 140 #endif
 141
 142 /* XXX cli/sti -> local_irq_xxx here, check this works once SMP is fixed. */
 143 void machine_halt(void)
 144 {
 145         local_irq_enable();
 146         mdelay(8);
 147         local_irq_disable();
 148         prom_halt();
 149         panic("Halt failed!");
 150 }
 151
 152 void machine_restart(char * cmd)
 153 {
 154         char *p;
 155
 156         local_irq_enable();
 157         mdelay(8);
 158         local_irq_disable();
 159
 160         p = strchr (reboot_command, '\n');
 161         if (p) *p = 0;
 162         if (cmd)
 163                 prom_reboot(cmd);
 164         if (*reboot_command)
 165                 prom_reboot(reboot_command);
 166         prom_feval ("reset");
 167         panic("Reboot failed!");
 168 }
 169
 170 void machine_power_off(void)
 171 {
 172 #ifdef CONFIG_SUN_AUXIO
 173         if (auxio_power_register &&
 174             (strcmp(of_console_device->type, "serial") || scons_pwroff))
 175                 *auxio_power_register |= AUXIO_POWER_OFF;
 176 #endif
 177         machine_halt();
 178 }
 179
 180 static DEFINE_SPINLOCK(sparc_backtrace_lock);
 181
 182 void __show_backtrace(unsigned long fp)
 183 {
 184         struct reg_window *rw;
 185         unsigned long flags;
 186         int cpu = smp_processor_id();
 187
 188         spin_lock_irqsave(&sparc_backtrace_lock, flags);
 189
 190         rw = (struct reg_window *)fp;
 191         while(rw && (((unsigned long) rw) >= PAGE_OFFSET) &&
 192             !(((unsigned long) rw) & 0x7)) {
 193                 printk("CPU[%d]: ARGS[%08lx,%08lx,%08lx,%08lx,%08lx,%08lx] "
 194                        "FP[%08lx] CALLER[%08lx]: ", cpu,
 195                        rw->ins[0], rw->ins[1], rw->ins[2], rw->ins[3],
 196                        rw->ins[4], rw->ins[5],
 197                        rw->ins[6],
 198                        rw->ins[7]);
 199                 print_symbol("%s\n", rw->ins[7]);
 200                 rw = (struct reg_window *) rw->ins[6];
 201         }
 202         spin_unlock_irqrestore(&sparc_backtrace_lock, flags);
 203 }
 204
 205 #define __SAVE __asm__ __volatile__("save %sp, -0x40, %sp\n\t")
 206 #define __RESTORE __asm__ __volatile__("restore %g0, %g0, %g0\n\t")
 207 #define __GET_FP(fp) __asm__ __volatile__("mov %%i6, %0" : "=r" (fp))
 208
 209 void show_backtrace(void)
 210 {
 211         unsigned long fp;
 212
 213         __SAVE; __SAVE; __SAVE; __SAVE;
 214         __SAVE; __SAVE; __SAVE; __SAVE;
 215         __RESTORE; __RESTORE; __RESTORE; __RESTORE;
 216         __RESTORE; __RESTORE; __RESTORE; __RESTORE;
 217
 218         __GET_FP(fp);
 219
 220         __show_backtrace(fp);
 221 }
 222
 223 #ifdef CONFIG_SMP
 224 void smp_show_backtrace_all_cpus(void)
 225 {
 226         xc0((smpfunc_t) show_backtrace);
 227         show_backtrace();
 228 }
 229 #endif
 230
 231 #if 0
 232 void show_stackframe(struct sparc_stackf *sf)
 233 {
 234         unsigned long size;
 235         unsigned long *stk;
 236         int i;
 237
 238         printk("l0: %08lx l1: %08lx l2: %08lx l3: %08lx "
 239                "l4: %08lx l5: %08lx l6: %08lx l7: %08lx\n",
 240                sf->locals[0], sf->locals[1], sf->locals[2], sf->locals[3],
 241                sf->locals[4], sf->locals[5], sf->locals[6], sf->locals[7]);
 242         printk("i0: %08lx i1: %08lx i2: %08lx i3: %08lx "
 243                "i4: %08lx i5: %08lx fp: %08lx i7: %08lx\n",
 244                sf->ins[0], sf->ins[1], sf->ins[2], sf->ins[3],
 245                sf->ins[4], sf->ins[5], (unsigned long)sf->fp, sf->callers_pc);
 246         printk("sp: %08lx x0: %08lx x1: %08lx x2: %08lx "
 247                "x3: %08lx x4: %08lx x5: %08lx xx: %08lx\n",
 248                (unsigned long)sf->structptr, sf->xargs[0], sf->xargs[1],
 249                sf->xargs[2], sf->xargs[3], sf->xargs[4], sf->xargs[5],
 250                sf->xxargs[0]);
 251         size = ((unsigned long)sf->fp) - ((unsigned long)sf);
 252         size -= STACKFRAME_SZ;
 253         stk = (unsigned long *)((unsigned long)sf + STACKFRAME_SZ);
 254         i = 0;
 255         do {
 256                 printk("s%d: %08lx\n", i++, *stk++);
 257         } while ((size -= sizeof(unsigned long)));
 258 }
 259 #endif
 260
 261 void show_regs(struct pt_regs *r)
 262 {
 263         struct reg_window *rw = (struct reg_window *) r->u_regs[14];
 264
 265         printk("PSR: %08lx PC: %08lx NPC: %08lx Y: %08lx    %s\n",
 266                r->psr, r->pc, r->npc, r->y, print_tainted());
 267         print_symbol("PC: <%s>\n", r->pc);
 268         printk("%%G: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",
 269                r->u_regs[0], r->u_regs[1], r->u_regs[2], r->u_regs[3],
 270                r->u_regs[4], r->u_regs[5], r->u_regs[6], r->u_regs[7]);
 271         printk("%%O: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",
 272                r->u_regs[8], r->u_regs[9], r->u_regs[10], r->u_regs[11],
 273                r->u_regs[12], r->u_regs[13], r->u_regs[14], r->u_regs[15]);
 274         print_symbol("RPC: <%s>\n", r->u_regs[15]);
 275
 276         printk("%%L: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",
 277                rw->locals[0], rw->locals[1], rw->locals[2], rw->locals[3],
 278                rw->locals[4], rw->locals[5], rw->locals[6], rw->locals[7]);
 279         printk("%%I: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",
 280                rw->ins[0], rw->ins[1], rw->ins[2], rw->ins[3],
 281                rw->ins[4], rw->ins[5], rw->ins[6], rw->ins[7]);
 282 }
 283
 284 /*
 285  * The show_stack is an external API which we do not use ourselves.
 286  * The oops is printed in die_if_kernel.
 287  */
 288 void show_stack(struct task_struct *tsk, unsigned long *_ksp)
 289 {
 290         unsigned long pc, fp;
 291         unsigned long task_base;
 292         struct reg_window *rw;
 293         int count = 0;
 294
 295         if (tsk != NULL)
 296                 task_base = (unsigned long) task_stack_page(tsk);
 297         else
 298                 task_base = (unsigned long) current_thread_info();
 299
 300         fp = (unsigned long) _ksp;
 301         do {
 302                 /* Bogus frame pointer? */
 303                 if (fp < (task_base + sizeof(struct thread_info)) ||
 304                     fp >= (task_base + (PAGE_SIZE << 1)))
 305                         break;
 306                 rw = (struct reg_window *) fp;
 307                 pc = rw->ins[7];
 308                 printk("[%08lx : ", pc);
 309                 print_symbol("%s ] ", pc);
 310                 fp = rw->ins[6];
 311         } while (++count < 16);
 312         printk("\n");
 313 }
 314
 315 void dump_stack(void)
 316 {
 317         unsigned long *ksp;
 318
 319         __asm__ __volatile__("mov       %%fp, %0"
 320                              : "=r" (ksp));
 321         show_stack(current, ksp);
 322 }
 323
 324 EXPORT_SYMBOL(dump_stack);
 325
 326 /*
 327  * Note: sparc64 has a pretty intricated thread_saved_pc, check it out.
 328  */
 329 unsigned long thread_saved_pc(struct task_struct *tsk)
 330 {
 331         return task_thread_info(tsk)->kpc;
 332 }
 333
 334 /*
 335  * Free current thread data structures etc..
 336  */
 337 void exit_thread(void)
 338 {
 339 #ifndef CONFIG_SMP
 340         if(last_task_used_math == current) {
 341 #else
 342         if (test_thread_flag(TIF_USEDFPU)) {
 343 #endif
 344                 /* Keep process from leaving FPU in a bogon state. */
 345                 put_psr(get_psr() | PSR_EF);
 346                 fpsave(&current->thread.float_regs[0], &current->thread.fsr,
 347                        &current->thread.fpqueue[0], &current->thread.fpqdepth);
 348 #ifndef CONFIG_SMP
 349                 last_task_used_math = NULL;
 350 #else
 351                 clear_thread_flag(TIF_USEDFPU);
 352 #endif
 353         }
 354 }
 355
 356 void flush_thread(void)
 357 {
 358         current_thread_info()->w_saved = 0;
 359
 360         /* No new signal delivery by default */
 361         current->thread.new_signal = 0;
 362 #ifndef CONFIG_SMP
 363         if(last_task_used_math == current) {
 364 #else
 365         if (test_thread_flag(TIF_USEDFPU)) {
 366 #endif
 367                 /* Clean the fpu. */
 368                 put_psr(get_psr() | PSR_EF);
 369                 fpsave(&current->thread.float_regs[0], &current->thread.fsr,
 370                        &current->thread.fpqueue[0], &current->thread.fpqdepth);
 371 #ifndef CONFIG_SMP
 372                 last_task_used_math = NULL;
 373 #else
 374                 clear_thread_flag(TIF_USEDFPU);
 375 #endif
 376         }
 377
 378         /* Now, this task is no longer a kernel thread. */
 379         current->thread.current_ds = USER_DS;
 380         if (current->thread.flags & SPARC_FLAG_KTHREAD) {
 381                 current->thread.flags &= ~SPARC_FLAG_KTHREAD;
 382
 383                 /* We must fixup kregs as well. */
 384                 /* XXX This was not fixed for ti for a while, worked. Unused? */
 385                 current->thread.kregs = (struct pt_regs *)
 386                     (task_stack_page(current) + (THREAD_SIZE - TRACEREG_SZ));
 387         }
 388 }
 389
 390 static inline struct sparc_stackf __user *
 391 clone_stackframe(struct sparc_stackf __user *dst,
 392                  struct sparc_stackf __user *src)
 393 {
 394         unsigned long size, fp;
 395         struct sparc_stackf *tmp;
 396         struct sparc_stackf __user *sp;
 397
 398         if (get_user(tmp, &src->fp))
 399                 return NULL;
 400
 401         fp = (unsigned long) tmp;
 402         size = (fp - ((unsigned long) src));
 403         fp = (unsigned long) dst;
 404         sp = (struct sparc_stackf __user *)(fp - size);
 405
 406         /* do_fork() grabs the parent semaphore, we must release it
 407          * temporarily so we can build the child clone stack frame
 408          * without deadlocking.
 409          */
 410         if (__copy_user(sp, src, size))
 411                 sp = NULL;
 412         else if (put_user(fp, &sp->fp))
 413                 sp = NULL;
 414
 415         return sp;
 416 }
 417
 418 asmlinkage int sparc_do_fork(unsigned long clone_flags,
 419                              unsigned long stack_start,
 420                              struct pt_regs *regs,
 421                              unsigned long stack_size)
 422 {
 423         unsigned long parent_tid_ptr, child_tid_ptr;
 424
 425         parent_tid_ptr = regs->u_regs[UREG_I2];
 426         child_tid_ptr = regs->u_regs[UREG_I4];
 427
 428         return do_fork(clone_flags, stack_start,
 429                        regs, stack_size,
 430                        (int __user *) parent_tid_ptr,
 431                        (int __user *) child_tid_ptr);
 432 }
 433
 434 /* Copy a Sparc thread.  The fork() return value conventions
 435  * under SunOS are nothing short of bletcherous:
 436  * Parent -->  %o0 == childs  pid, %o1 == 0
 437  * Child  -->  %o0 == parents pid, %o1 == 1
 438  *
 439  * NOTE: We have a separate fork kpsr/kwim because
 440  *       the parent could change these values between
 441  *       sys_fork invocation and when we reach here
 442  *       if the parent should sleep while trying to
 443  *       allocate the task_struct and kernel stack in
 444  *       do_fork().
 445  * XXX See comment above sys_vfork in sparc64. todo.
 446  */
 447 extern void ret_from_fork(void);
 448
 449 int copy_thread(int nr, unsigned long clone_flags, unsigned long sp,
 450                 unsigned long unused,
 451                 struct task_struct *p, struct pt_regs *regs)
 452 {
 453         struct thread_info *ti = task_thread_info(p);
 454         struct pt_regs *childregs;
 455         char *new_stack;
 456
 457 #ifndef CONFIG_SMP
 458         if(last_task_used_math == current) {
 459 #else
 460         if (test_thread_flag(TIF_USEDFPU)) {
 461 #endif
 462                 put_psr(get_psr() | PSR_EF);
 463                 fpsave(&p->thread.float_regs[0], &p->thread.fsr,
 464                        &p->thread.fpqueue[0], &p->thread.fpqdepth);
 465 #ifdef CONFIG_SMP
 466                 clear_thread_flag(TIF_USEDFPU);
 467 #endif
 468         }
 469
 470         /*
 471          *  p->thread_info         new_stack   childregs
 472          *  !                      !           !             {if(PSR_PS) }
 473          *  V                      V (stk.fr.) V  (pt_regs)  { (stk.fr.) }
 474          *  +----- - - - - - ------+===========+============={+==========}+
 475          */
 476         new_stack = task_stack_page(p) + THREAD_SIZE;
 477         if (regs->psr & PSR_PS)
 478                 new_stack -= STACKFRAME_SZ;
 479         new_stack -= STACKFRAME_SZ + TRACEREG_SZ;
 480         memcpy(new_stack, (char *)regs - STACKFRAME_SZ, STACKFRAME_SZ + TRACEREG_SZ);
 481         childregs = (struct pt_regs *) (new_stack + STACKFRAME_SZ);
 482
 483         /*
 484          * A new process must start with interrupts closed in 2.5,
 485          * because this is how Mingo's scheduler works (see schedule_tail
 486          * and finish_arch_switch). If we do not do it, a timer interrupt hits
 487          * before we unlock, attempts to re-take the rq->lock, and then we die.
 488          * Thus, kpsr|=PSR_PIL.
 489          */
 490         ti->ksp = (unsigned long) new_stack;
 491         ti->kpc = (((unsigned long) ret_from_fork) - 0x8);
 492         ti->kpsr = current->thread.fork_kpsr | PSR_PIL;
 493         ti->kwim = current->thread.fork_kwim;
 494
 495         if(regs->psr & PSR_PS) {
 496                 extern struct pt_regs fake_swapper_regs;
 497
 498                 p->thread.kregs = &fake_swapper_regs;
 499                 new_stack += STACKFRAME_SZ + TRACEREG_SZ;
 500                 childregs->u_regs[UREG_FP] = (unsigned long) new_stack;
 501                 p->thread.flags |= SPARC_FLAG_KTHREAD;
 502                 p->thread.current_ds = KERNEL_DS;
 503                 memcpy(new_stack, (void *)regs->u_regs[UREG_FP], STACKFRAME_SZ);
 504                 childregs->u_regs[UREG_G6] = (unsigned long) ti;
 505         } else {
 506                 p->thread.kregs = childregs;
 507                 childregs->u_regs[UREG_FP] = sp;
 508                 p->thread.flags &= ~SPARC_FLAG_KTHREAD;
 509                 p->thread.current_ds = USER_DS;
 510
 511                 if (sp != regs->u_regs[UREG_FP]) {
 512                         struct sparc_stackf __user *childstack;
 513                         struct sparc_stackf __user *parentstack;
 514
 515                         /*
 516                          * This is a clone() call with supplied user stack.
 517                          * Set some valid stack frames to give to the child.
 518                          */
 519                         childstack = (struct sparc_stackf __user *)
 520                                 (sp & ~0x7UL);
 521                         parentstack = (struct sparc_stackf __user *)
 522                                 regs->u_regs[UREG_FP];
 523
 524 #if 0
 525                         printk("clone: parent stack:\n");
 526                         show_stackframe(parentstack);
 527 #endif
 528
 529                         childstack = clone_stackframe(childstack, parentstack);
 530                         if (!childstack)
 531                                 return -EFAULT;
 532
 533 #if 0
 534                         printk("clone: child stack:\n");
 535                         show_stackframe(childstack);
 536 #endif
 537
 538                         childregs->u_regs[UREG_FP] = (unsigned long)childstack;
 539                 }
 540         }
 541
 542 #ifdef CONFIG_SMP
 543         /* FPU must be disabled on SMP. */
 544         childregs->psr &= ~PSR_EF;
 545 #endif
 546
 547         /* Set the return value for the child. */
 548         childregs->u_regs[UREG_I0] = current->pid;
 549         childregs->u_regs[UREG_I1] = 1;
 550
 551         /* Set the return value for the parent. */
 552         regs->u_regs[UREG_I1] = 0;
 553
 554         if (clone_flags & CLONE_SETTLS)
 555                 childregs->u_regs[UREG_G7] = regs->u_regs[UREG_I3];
 556
 557         return 0;
 558 }
 559
 560 /*
 561  * fill in the fpu structure for a core dump.
 562  */
 563 int dump_fpu (struct pt_regs * regs, elf_fpregset_t * fpregs)
 564 {
 565         if (used_math()) {
 566                 memset(fpregs, 0, sizeof(*fpregs));
 567                 fpregs->pr_q_entrysize = 8;
 568                 return 1;
 569         }
 570 #ifdef CONFIG_SMP
 571         if (test_thread_flag(TIF_USEDFPU)) {
 572                 put_psr(get_psr() | PSR_EF);
 573                 fpsave(&current->thread.float_regs[0], &current->thread.fsr,
 574                        &current->thread.fpqueue[0], &current->thread.fpqdepth);
 575                 if (regs != NULL) {
 576                         regs->psr &= ~(PSR_EF);
 577                         clear_thread_flag(TIF_USEDFPU);
 578                 }
 579         }
 580 #else
 581         if (current == last_task_used_math) {
 582                 put_psr(get_psr() | PSR_EF);
 583                 fpsave(&current->thread.float_regs[0], &current->thread.fsr,
 584                        &current->thread.fpqueue[0], &current->thread.fpqdepth);
 585                 if (regs != NULL) {
 586                         regs->psr &= ~(PSR_EF);
 587                         last_task_used_math = NULL;
 588                 }
 589         }
 590 #endif
 591         memcpy(&fpregs->pr_fr.pr_regs[0],
 592                &current->thread.float_regs[0],
 593                (sizeof(unsigned long) * 32));
 594         fpregs->pr_fsr = current->thread.fsr;
 595         fpregs->pr_qcnt = current->thread.fpqdepth;
 596         fpregs->pr_q_entrysize = 8;
 597         fpregs->pr_en = 1;
 598         if(fpregs->pr_qcnt != 0) {
 599                 memcpy(&fpregs->pr_q[0],
 600                        &current->thread.fpqueue[0],
 601                        sizeof(struct fpq) * fpregs->pr_qcnt);
 602         }
 603         /* Zero out the rest. */
 604         memset(&fpregs->pr_q[fpregs->pr_qcnt], 0,
 605                sizeof(struct fpq) * (32 - fpregs->pr_qcnt));
 606         return 1;
 607 }
 608
 609 /*
 610  * sparc_execve() executes a new program after the asm stub has set
 611  * things up for us.  This should basically do what I want it to.
 612  */
 613 asmlinkage int sparc_execve(struct pt_regs *regs)
 614 {
 615         int error, base = 0;
 616         char *filename;
 617
 618         /* Check for indirect call. */
 619         if(regs->u_regs[UREG_G1] == 0)
 620                 base = 1;
 621
 622         filename = getname((char __user *)regs->u_regs[base + UREG_I0]);
 623         error = PTR_ERR(filename);
 624         if(IS_ERR(filename))
 625                 goto out;
 626         error = do_execve(filename,
 627                           (char __user * __user *)regs->u_regs[base + UREG_I1],
 628                           (char __user * __user *)regs->u_regs[base + UREG_I2],
 629                           regs);
 630         putname(filename);
 631         if (error == 0) {
 632                 task_lock(current);
 633                 current->ptrace &= ~PT_DTRACE;
 634                 task_unlock(current);
 635         }
 636 out:
 637         return error;
 638 }
 639
 640 /*
 641  * This is the mechanism for creating a new kernel thread.
 642  *
 643  * NOTE! Only a kernel-only process(ie the swapper or direct descendants
 644  * who haven't done an "execve()") should use this: it will work within
 645  * a system call from a "real" process, but the process memory space will
 646  * not be freed until both the parent and the child have exited.
 647  */
 648 pid_t kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
 649 {
 650         long retval;
 651
 652         __asm__ __volatile__("mov %4, %%g2\n\t"    /* Set aside fn ptr... */
 653                              "mov %5, %%g3\n\t"    /* and arg. */
 654                              "mov %1, %%g1\n\t"
 655                              "mov %2, %%o0\n\t"    /* Clone flags. */
 656                              "mov 0, %%o1\n\t"     /* usp arg == 0 */
 657                              "t 0x10\n\t"          /* Linux/Sparc clone(). */
 658                              "cmp %%o1, 0\n\t"
 659                              "be 1f\n\t"           /* The parent, just return. */
 660                              " nop\n\t"            /* Delay slot. */
 661                              "jmpl %%g2, %%o7\n\t" /* Call the function. */
 662                              " mov %%g3, %%o0\n\t" /* Get back the arg in delay. */
 663                              "mov %3, %%g1\n\t"
 664                              "t 0x10\n\t"          /* Linux/Sparc exit(). */
 665                              /* Notreached by child. */
 666                              "1: mov %%o0, %0\n\t" :
 667                              "=r" (retval) :
 668                              "i" (__NR_clone), "r" (flags | CLONE_VM | CLONE_UNTRACED),
 669                              "i" (__NR_exit),  "r" (fn), "r" (arg) :
 670                              "g1", "g2", "g3", "o0", "o1", "memory", "cc");
 671         return retval;
 672 }
 673
 674 unsigned long get_wchan(struct task_struct *task)
 675 {
 676         unsigned long pc, fp, bias = 0;
 677         unsigned long task_base = (unsigned long) task;
 678         unsigned long ret = 0;
 679         struct reg_window *rw;
 680         int count = 0;
 681
 682         if (!task || task == current ||
 683             task->state == TASK_RUNNING)
 684                 goto out;
 685
 686         fp = task_thread_info(task)->ksp + bias;
 687         do {
 688                 /* Bogus frame pointer? */
 689                 if (fp < (task_base + sizeof(struct thread_info)) ||
 690                     fp >= (task_base + (2 * PAGE_SIZE)))
 691                         break;
 692                 rw = (struct reg_window *) fp;
 693                 pc = rw->ins[7];
 694                 if (!in_sched_functions(pc)) {
 695                         ret = pc;
 696                         goto out;
 697                 }
 698                 fp = rw->ins[6] + bias;
 699         } while (++count < 16);
 700
 701 out:
 702         return ret;
 703 }
 704