arch/sparc/kernel/process_32.c

   1 /*  linux/arch/sparc/kernel/process.c
   2  *
   3  *  Copyright (C) 1995, 2008 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/mm.h>
  18 #include <linux/stddef.h>
  19 #include <linux/ptrace.h>
  20 #include <linux/user.h>
  21 #include <linux/smp.h>
  22 #include <linux/reboot.h>
  23 #include <linux/delay.h>
  24 #include <linux/pm.h>
  25 #include <linux/init.h>
  26 #include <linux/slab.h>
  27
  28 #include <asm/auxio.h>
  29 #include <asm/oplib.h>
  30 #include <asm/uaccess.h>
  31 #include <asm/system.h>
  32 #include <asm/page.h>
  33 #include <asm/pgalloc.h>
  34 #include <asm/pgtable.h>
  35 #include <asm/delay.h>
  36 #include <asm/processor.h>
  37 #include <asm/psr.h>
  38 #include <asm/elf.h>
  39 #include <asm/prom.h>
  40 #include <asm/unistd.h>
  41
  42 /*
  43  * Power management idle function
  44  * Set in pm platform drivers (apc.c and pmc.c)
  45  */
  46 void (*pm_idle)(void);
  47 EXPORT_SYMBOL(pm_idle);
  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) {
  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 #ifdef CONFIG_SPARC_LEON
 132                 if (pm_idle) {
 133                         while (!need_resched())
 134                                 (*pm_idle)();
 135                 } else
 136 #endif
 137                 {
 138                         while (!need_resched())
 139                                 cpu_relax();
 140                 }
 141                 preempt_enable_no_resched();
 142                 schedule();
 143                 preempt_disable();
 144                 check_pgt_cache();
 145         }
 146 }
 147
 148 #endif
 149
 150 /* XXX cli/sti -> local_irq_xxx here, check this works once SMP is fixed. */
 151 void machine_halt(void)
 152 {
 153         local_irq_enable();
 154         mdelay(8);
 155         local_irq_disable();
 156         prom_halt();
 157         panic("Halt failed!");
 158 }
 159
 160 void machine_restart(char * cmd)
 161 {
 162         char *p;
 163
 164         local_irq_enable();
 165         mdelay(8);
 166         local_irq_disable();
 167
 168         p = strchr (reboot_command, '\n');
 169         if (p) *p = 0;
 170         if (cmd)
 171                 prom_reboot(cmd);
 172         if (*reboot_command)
 173                 prom_reboot(reboot_command);
 174         prom_feval ("reset");
 175         panic("Reboot failed!");
 176 }
 177
 178 void machine_power_off(void)
 179 {
 180         if (auxio_power_register &&
 181             (strcmp(of_console_device->type, "serial") || scons_pwroff))
 182                 *auxio_power_register |= AUXIO_POWER_OFF;
 183         machine_halt();
 184 }
 185
 186 #if 0
 187
 188 static DEFINE_SPINLOCK(sparc_backtrace_lock);
 189
 190 void __show_backtrace(unsigned long fp)
 191 {
 192         struct reg_window32 *rw;
 193         unsigned long flags;
 194         int cpu = smp_processor_id();
 195
 196         spin_lock_irqsave(&sparc_backtrace_lock, flags);
 197
 198         rw = (struct reg_window32 *)fp;
 199         while(rw && (((unsigned long) rw) >= PAGE_OFFSET) &&
 200             !(((unsigned long) rw) & 0x7)) {
 201                 printk("CPU[%d]: ARGS[%08lx,%08lx,%08lx,%08lx,%08lx,%08lx] "
 202                        "FP[%08lx] CALLER[%08lx]: ", cpu,
 203                        rw->ins[0], rw->ins[1], rw->ins[2], rw->ins[3],
 204                        rw->ins[4], rw->ins[5],
 205                        rw->ins[6],
 206                        rw->ins[7]);
 207                 printk("%pS\n", (void *) rw->ins[7]);
 208                 rw = (struct reg_window32 *) rw->ins[6];
 209         }
 210         spin_unlock_irqrestore(&sparc_backtrace_lock, flags);
 211 }
 212
 213 #define __SAVE __asm__ __volatile__("save %sp, -0x40, %sp\n\t")
 214 #define __RESTORE __asm__ __volatile__("restore %g0, %g0, %g0\n\t")
 215 #define __GET_FP(fp) __asm__ __volatile__("mov %%i6, %0" : "=r" (fp))
 216
 217 void show_backtrace(void)
 218 {
 219         unsigned long fp;
 220
 221         __SAVE; __SAVE; __SAVE; __SAVE;
 222         __SAVE; __SAVE; __SAVE; __SAVE;
 223         __RESTORE; __RESTORE; __RESTORE; __RESTORE;
 224         __RESTORE; __RESTORE; __RESTORE; __RESTORE;
 225
 226         __GET_FP(fp);
 227
 228         __show_backtrace(fp);
 229 }
 230
 231 #ifdef CONFIG_SMP
 232 void smp_show_backtrace_all_cpus(void)
 233 {
 234         xc0((smpfunc_t) show_backtrace);
 235         show_backtrace();
 236 }
 237 #endif
 238
 239 void show_stackframe(struct sparc_stackf *sf)
 240 {
 241         unsigned long size;
 242         unsigned long *stk;
 243         int i;
 244
 245         printk("l0: %08lx l1: %08lx l2: %08lx l3: %08lx "
 246                "l4: %08lx l5: %08lx l6: %08lx l7: %08lx\n",
 247                sf->locals[0], sf->locals[1], sf->locals[2], sf->locals[3],
 248                sf->locals[4], sf->locals[5], sf->locals[6], sf->locals[7]);
 249         printk("i0: %08lx i1: %08lx i2: %08lx i3: %08lx "
 250                "i4: %08lx i5: %08lx fp: %08lx i7: %08lx\n",
 251                sf->ins[0], sf->ins[1], sf->ins[2], sf->ins[3],
 252                sf->ins[4], sf->ins[5], (unsigned long)sf->fp, sf->callers_pc);
 253         printk("sp: %08lx x0: %08lx x1: %08lx x2: %08lx "
 254                "x3: %08lx x4: %08lx x5: %08lx xx: %08lx\n",
 255                (unsigned long)sf->structptr, sf->xargs[0], sf->xargs[1],
 256                sf->xargs[2], sf->xargs[3], sf->xargs[4], sf->xargs[5],
 257                sf->xxargs[0]);
 258         size = ((unsigned long)sf->fp) - ((unsigned long)sf);
 259         size -= STACKFRAME_SZ;
 260         stk = (unsigned long *)((unsigned long)sf + STACKFRAME_SZ);
 261         i = 0;
 262         do {
 263                 printk("s%d: %08lx\n", i++, *stk++);
 264         } while ((size -= sizeof(unsigned long)));
 265 }
 266 #endif
 267
 268 void show_regs(struct pt_regs *r)
 269 {
 270         struct reg_window32 *rw = (struct reg_window32 *) r->u_regs[14];
 271
 272         printk("PSR: %08lx PC: %08lx NPC: %08lx Y: %08lx    %s\n",
 273                r->psr, r->pc, r->npc, r->y, print_tainted());
 274         printk("PC: <%pS>\n", (void *) r->pc);
 275         printk("%%G: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",
 276                r->u_regs[0], r->u_regs[1], r->u_regs[2], r->u_regs[3],
 277                r->u_regs[4], r->u_regs[5], r->u_regs[6], r->u_regs[7]);
 278         printk("%%O: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",
 279                r->u_regs[8], r->u_regs[9], r->u_regs[10], r->u_regs[11],
 280                r->u_regs[12], r->u_regs[13], r->u_regs[14], r->u_regs[15]);
 281         printk("RPC: <%pS>\n", (void *) r->u_regs[15]);
 282
 283         printk("%%L: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",
 284                rw->locals[0], rw->locals[1], rw->locals[2], rw->locals[3],
 285                rw->locals[4], rw->locals[5], rw->locals[6], rw->locals[7]);
 286         printk("%%I: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",
 287                rw->ins[0], rw->ins[1], rw->ins[2], rw->ins[3],
 288                rw->ins[4], rw->ins[5], rw->ins[6], rw->ins[7]);
 289 }
 290
 291 /*
 292  * The show_stack is an external API which we do not use ourselves.
 293  * The oops is printed in die_if_kernel.
 294  */
 295 void show_stack(struct task_struct *tsk, unsigned long *_ksp)
 296 {
 297         unsigned long pc, fp;
 298         unsigned long task_base;
 299         struct reg_window32 *rw;
 300         int count = 0;
 301
 302         if (tsk != NULL)
 303                 task_base = (unsigned long) task_stack_page(tsk);
 304         else
 305                 task_base = (unsigned long) current_thread_info();
 306
 307         fp = (unsigned long) _ksp;
 308         do {
 309                 /* Bogus frame pointer? */
 310                 if (fp < (task_base + sizeof(struct thread_info)) ||
 311                     fp >= (task_base + (PAGE_SIZE << 1)))
 312                         break;
 313                 rw = (struct reg_window32 *) fp;
 314                 pc = rw->ins[7];
 315                 printk("[%08lx : ", pc);
 316                 printk("%pS ] ", (void *) pc);
 317                 fp = rw->ins[6];
 318         } while (++count < 16);
 319         printk("\n");
 320 }
 321
 322 void dump_stack(void)
 323 {
 324         unsigned long *ksp;
 325
 326         __asm__ __volatile__("mov       %%fp, %0"
 327                              : "=r" (ksp));
 328         show_stack(current, ksp);
 329 }
 330
 331 EXPORT_SYMBOL(dump_stack);
 332
 333 /*
 334  * Note: sparc64 has a pretty intricated thread_saved_pc, check it out.
 335  */
 336 unsigned long thread_saved_pc(struct task_struct *tsk)
 337 {
 338         return task_thread_info(tsk)->kpc;
 339 }
 340
 341 /*
 342  * Free current thread data structures etc..
 343  */
 344 void exit_thread(void)
 345 {
 346 #ifndef CONFIG_SMP
 347         if(last_task_used_math == current) {
 348 #else
 349         if (test_thread_flag(TIF_USEDFPU)) {
 350 #endif
 351                 /* Keep process from leaving FPU in a bogon state. */
 352                 put_psr(get_psr() | PSR_EF);
 353                 fpsave(&current->thread.float_regs[0], &current->thread.fsr,
 354                        &current->thread.fpqueue[0], &current->thread.fpqdepth);
 355 #ifndef CONFIG_SMP
 356                 last_task_used_math = NULL;
 357 #else
 358                 clear_thread_flag(TIF_USEDFPU);
 359 #endif
 360         }
 361 }
 362
 363 void flush_thread(void)
 364 {
 365         current_thread_info()->w_saved = 0;
 366
 367 #ifndef CONFIG_SMP
 368         if(last_task_used_math == current) {
 369 #else
 370         if (test_thread_flag(TIF_USEDFPU)) {
 371 #endif
 372                 /* Clean the fpu. */
 373                 put_psr(get_psr() | PSR_EF);
 374                 fpsave(&current->thread.float_regs[0], &current->thread.fsr,
 375                        &current->thread.fpqueue[0], &current->thread.fpqdepth);
 376 #ifndef CONFIG_SMP
 377                 last_task_used_math = NULL;
 378 #else
 379                 clear_thread_flag(TIF_USEDFPU);
 380 #endif
 381         }
 382
 383         /* This task is no longer a kernel thread. */
 384         if (current->thread.flags & SPARC_FLAG_KTHREAD) {
 385                 current->thread.flags &= ~SPARC_FLAG_KTHREAD;
 386
 387                 /* We must fixup kregs as well. */
 388                 /* XXX This was not fixed for ti for a while, worked. Unused? */
 389                 current->thread.kregs = (struct pt_regs *)
 390                     (task_stack_page(current) + (THREAD_SIZE - TRACEREG_SZ));
 391         }
 392 }
 393
 394 static inline struct sparc_stackf __user *
 395 clone_stackframe(struct sparc_stackf __user *dst,
 396                  struct sparc_stackf __user *src)
 397 {
 398         unsigned long size, fp;
 399         struct sparc_stackf *tmp;
 400         struct sparc_stackf __user *sp;
 401
 402         if (get_user(tmp, &src->fp))
 403                 return NULL;
 404
 405         fp = (unsigned long) tmp;
 406         size = (fp - ((unsigned long) src));
 407         fp = (unsigned long) dst;
 408         sp = (struct sparc_stackf __user *)(fp - size);
 409
 410         /* do_fork() grabs the parent semaphore, we must release it
 411          * temporarily so we can build the child clone stack frame
 412          * without deadlocking.
 413          */
 414         if (__copy_user(sp, src, size))
 415                 sp = NULL;
 416         else if (put_user(fp, &sp->fp))
 417                 sp = NULL;
 418
 419         return sp;
 420 }
 421
 422 asmlinkage int sparc_do_fork(unsigned long clone_flags,
 423                              unsigned long stack_start,
 424                              struct pt_regs *regs,
 425                              unsigned long stack_size)
 426 {
 427         unsigned long parent_tid_ptr, child_tid_ptr;
 428         unsigned long orig_i1 = regs->u_regs[UREG_I1];
 429         long ret;
 430
 431         parent_tid_ptr = regs->u_regs[UREG_I2];
 432         child_tid_ptr = regs->u_regs[UREG_I4];
 433
 434         ret = do_fork(clone_flags, stack_start,
 435                       regs, stack_size,
 436                       (int __user *) parent_tid_ptr,
 437                       (int __user *) child_tid_ptr);
 438
 439         /* If we get an error and potentially restart the system
 440          * call, we're screwed because copy_thread() clobbered
 441          * the parent's %o1.  So detect that case and restore it
 442          * here.
 443          */
 444         if ((unsigned long)ret >= -ERESTART_RESTARTBLOCK)
 445                 regs->u_regs[UREG_I1] = orig_i1;
 446
 447         return ret;
 448 }
 449
 450 /* Copy a Sparc thread.  The fork() return value conventions
 451  * under SunOS are nothing short of bletcherous:
 452  * Parent -->  %o0 == childs  pid, %o1 == 0
 453  * Child  -->  %o0 == parents pid, %o1 == 1
 454  *
 455  * NOTE: We have a separate fork kpsr/kwim because
 456  *       the parent could change these values between
 457  *       sys_fork invocation and when we reach here
 458  *       if the parent should sleep while trying to
 459  *       allocate the task_struct and kernel stack in
 460  *       do_fork().
 461  * XXX See comment above sys_vfork in sparc64. todo.
 462  */
 463 extern void ret_from_fork(void);
 464
 465 int copy_thread(unsigned long clone_flags, unsigned long sp,
 466                 unsigned long unused,
 467                 struct task_struct *p, struct pt_regs *regs)
 468 {
 469         struct thread_info *ti = task_thread_info(p);
 470         struct pt_regs *childregs;
 471         char *new_stack;
 472
 473 #ifndef CONFIG_SMP
 474         if(last_task_used_math == current) {
 475 #else
 476         if (test_thread_flag(TIF_USEDFPU)) {
 477 #endif
 478                 put_psr(get_psr() | PSR_EF);
 479                 fpsave(&p->thread.float_regs[0], &p->thread.fsr,
 480                        &p->thread.fpqueue[0], &p->thread.fpqdepth);
 481 #ifdef CONFIG_SMP
 482                 clear_thread_flag(TIF_USEDFPU);
 483 #endif
 484         }
 485
 486         /*
 487          *  p->thread_info         new_stack   childregs
 488          *  !                      !           !             {if(PSR_PS) }
 489          *  V                      V (stk.fr.) V  (pt_regs)  { (stk.fr.) }
 490          *  +----- - - - - - ------+===========+============={+==========}+
 491          */
 492         new_stack = task_stack_page(p) + THREAD_SIZE;
 493         if (regs->psr & PSR_PS)
 494                 new_stack -= STACKFRAME_SZ;
 495         new_stack -= STACKFRAME_SZ + TRACEREG_SZ;
 496         memcpy(new_stack, (char *)regs - STACKFRAME_SZ, STACKFRAME_SZ + TRACEREG_SZ);
 497         childregs = (struct pt_regs *) (new_stack + STACKFRAME_SZ);
 498
 499         /*
 500          * A new process must start with interrupts closed in 2.5,
 501          * because this is how Mingo's scheduler works (see schedule_tail
 502          * and finish_arch_switch). If we do not do it, a timer interrupt hits
 503          * before we unlock, attempts to re-take the rq->lock, and then we die.
 504          * Thus, kpsr|=PSR_PIL.
 505          */
 506         ti->ksp = (unsigned long) new_stack;
 507         ti->kpc = (((unsigned long) ret_from_fork) - 0x8);
 508         ti->kpsr = current->thread.fork_kpsr | PSR_PIL;
 509         ti->kwim = current->thread.fork_kwim;
 510
 511         if(regs->psr & PSR_PS) {
 512                 extern struct pt_regs fake_swapper_regs;
 513
 514                 p->thread.kregs = &fake_swapper_regs;
 515                 new_stack += STACKFRAME_SZ + TRACEREG_SZ;
 516                 childregs->u_regs[UREG_FP] = (unsigned long) new_stack;
 517                 p->thread.flags |= SPARC_FLAG_KTHREAD;
 518                 p->thread.current_ds = KERNEL_DS;
 519                 memcpy(new_stack, (void *)regs->u_regs[UREG_FP], STACKFRAME_SZ);
 520                 childregs->u_regs[UREG_G6] = (unsigned long) ti;
 521         } else {
 522                 p->thread.kregs = childregs;
 523                 childregs->u_regs[UREG_FP] = sp;
 524                 p->thread.flags &= ~SPARC_FLAG_KTHREAD;
 525                 p->thread.current_ds = USER_DS;
 526
 527                 if (sp != regs->u_regs[UREG_FP]) {
 528                         struct sparc_stackf __user *childstack;
 529                         struct sparc_stackf __user *parentstack;
 530
 531                         /*
 532                          * This is a clone() call with supplied user stack.
 533                          * Set some valid stack frames to give to the child.
 534                          */
 535                         childstack = (struct sparc_stackf __user *)
 536                                 (sp & ~0xfUL);
 537                         parentstack = (struct sparc_stackf __user *)
 538                                 regs->u_regs[UREG_FP];
 539
 540 #if 0
 541                         printk("clone: parent stack:\n");
 542                         show_stackframe(parentstack);
 543 #endif
 544
 545                         childstack = clone_stackframe(childstack, parentstack);
 546                         if (!childstack)
 547                                 return -EFAULT;
 548
 549 #if 0
 550                         printk("clone: child stack:\n");
 551                         show_stackframe(childstack);
 552 #endif
 553
 554                         childregs->u_regs[UREG_FP] = (unsigned long)childstack;
 555                 }
 556         }
 557
 558 #ifdef CONFIG_SMP
 559         /* FPU must be disabled on SMP. */
 560         childregs->psr &= ~PSR_EF;
 561 #endif
 562
 563         /* Set the return value for the child. */
 564         childregs->u_regs[UREG_I0] = current->pid;
 565         childregs->u_regs[UREG_I1] = 1;
 566
 567         /* Set the return value for the parent. */
 568         regs->u_regs[UREG_I1] = 0;
 569
 570         if (clone_flags & CLONE_SETTLS)
 571                 childregs->u_regs[UREG_G7] = regs->u_regs[UREG_I3];
 572
 573         return 0;
 574 }
 575
 576 /*
 577  * fill in the fpu structure for a core dump.
 578  */
 579 int dump_fpu (struct pt_regs * regs, elf_fpregset_t * fpregs)
 580 {
 581         if (used_math()) {
 582                 memset(fpregs, 0, sizeof(*fpregs));
 583                 fpregs->pr_q_entrysize = 8;
 584                 return 1;
 585         }
 586 #ifdef CONFIG_SMP
 587         if (test_thread_flag(TIF_USEDFPU)) {
 588                 put_psr(get_psr() | PSR_EF);
 589                 fpsave(&current->thread.float_regs[0], &current->thread.fsr,
 590                        &current->thread.fpqueue[0], &current->thread.fpqdepth);
 591                 if (regs != NULL) {
 592                         regs->psr &= ~(PSR_EF);
 593                         clear_thread_flag(TIF_USEDFPU);
 594                 }
 595         }
 596 #else
 597         if (current == last_task_used_math) {
 598                 put_psr(get_psr() | PSR_EF);
 599                 fpsave(&current->thread.float_regs[0], &current->thread.fsr,
 600                        &current->thread.fpqueue[0], &current->thread.fpqdepth);
 601                 if (regs != NULL) {
 602                         regs->psr &= ~(PSR_EF);
 603                         last_task_used_math = NULL;
 604                 }
 605         }
 606 #endif
 607         memcpy(&fpregs->pr_fr.pr_regs[0],
 608                &current->thread.float_regs[0],
 609                (sizeof(unsigned long) * 32));
 610         fpregs->pr_fsr = current->thread.fsr;
 611         fpregs->pr_qcnt = current->thread.fpqdepth;
 612         fpregs->pr_q_entrysize = 8;
 613         fpregs->pr_en = 1;
 614         if(fpregs->pr_qcnt != 0) {
 615                 memcpy(&fpregs->pr_q[0],
 616                        &current->thread.fpqueue[0],
 617                        sizeof(struct fpq) * fpregs->pr_qcnt);
 618         }
 619         /* Zero out the rest. */
 620         memset(&fpregs->pr_q[fpregs->pr_qcnt], 0,
 621                sizeof(struct fpq) * (32 - fpregs->pr_qcnt));
 622         return 1;
 623 }
 624
 625 /*
 626  * sparc_execve() executes a new program after the asm stub has set
 627  * things up for us.  This should basically do what I want it to.
 628  */
 629 asmlinkage int sparc_execve(struct pt_regs *regs)
 630 {
 631         int error, base = 0;
 632         char *filename;
 633
 634         /* Check for indirect call. */
 635         if(regs->u_regs[UREG_G1] == 0)
 636                 base = 1;
 637
 638         filename = getname((char __user *)regs->u_regs[base + UREG_I0]);
 639         error = PTR_ERR(filename);
 640         if(IS_ERR(filename))
 641                 goto out;
 642         error = do_execve(filename,
 643                           (const char __user *const  __user *)
 644                           regs->u_regs[base + UREG_I1],
 645                           (const char __user *const  __user *)
 646                           regs->u_regs[base + UREG_I2],
 647                           regs);
 648         putname(filename);
 649 out:
 650         return error;
 651 }
 652
 653 /*
 654  * This is the mechanism for creating a new kernel thread.
 655  *
 656  * NOTE! Only a kernel-only process(ie the swapper or direct descendants
 657  * who haven't done an "execve()") should use this: it will work within
 658  * a system call from a "real" process, but the process memory space will
 659  * not be freed until both the parent and the child have exited.
 660  */
 661 pid_t kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
 662 {
 663         long retval;
 664
 665         __asm__ __volatile__("mov %4, %%g2\n\t"    /* Set aside fn ptr... */
 666                              "mov %5, %%g3\n\t"    /* and arg. */
 667                              "mov %1, %%g1\n\t"
 668                              "mov %2, %%o0\n\t"    /* Clone flags. */
 669                              "mov 0, %%o1\n\t"     /* usp arg == 0 */
 670                              "t 0x10\n\t"          /* Linux/Sparc clone(). */
 671                              "cmp %%o1, 0\n\t"
 672                              "be 1f\n\t"           /* The parent, just return. */
 673                              " nop\n\t"            /* Delay slot. */
 674                              "jmpl %%g2, %%o7\n\t" /* Call the function. */
 675                              " mov %%g3, %%o0\n\t" /* Get back the arg in delay. */
 676                              "mov %3, %%g1\n\t"
 677                              "t 0x10\n\t"          /* Linux/Sparc exit(). */
 678                              /* Notreached by child. */
 679                              "1: mov %%o0, %0\n\t" :
 680                              "=r" (retval) :
 681                              "i" (__NR_clone), "r" (flags | CLONE_VM | CLONE_UNTRACED),
 682                              "i" (__NR_exit),  "r" (fn), "r" (arg) :
 683                              "g1", "g2", "g3", "o0", "o1", "memory", "cc");
 684         return retval;
 685 }
 686 EXPORT_SYMBOL(kernel_thread);
 687
 688 unsigned long get_wchan(struct task_struct *task)
 689 {
 690         unsigned long pc, fp, bias = 0;
 691         unsigned long task_base = (unsigned long) task;
 692         unsigned long ret = 0;
 693         struct reg_window32 *rw;
 694         int count = 0;
 695
 696         if (!task || task == current ||
 697             task->state == TASK_RUNNING)
 698                 goto out;
 699
 700         fp = task_thread_info(task)->ksp + bias;
 701         do {
 702                 /* Bogus frame pointer? */
 703                 if (fp < (task_base + sizeof(struct thread_info)) ||
 704                     fp >= (task_base + (2 * PAGE_SIZE)))
 705                         break;
 706                 rw = (struct reg_window32 *) fp;
 707                 pc = rw->ins[7];
 708                 if (!in_sched_functions(pc)) {
 709                         ret = pc;
 710                         goto out;
 711                 }
 712                 fp = rw->ins[6] + bias;
 713         } while (++count < 16);
 714
 715 out:
 716         return ret;
 717 }
 718