arch/sparc/kernel/process.c

   1 /*  $Id: process.c,v 1.161 2002/01/23 11:27:32 davem Exp $
   2  *  linux/arch/sparc/kernel/process.c
   3  *
   4  *  Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
   5  *  Copyright (C) 1996 Eddie C. Dost   (ecd@skynet.be)
   6  */
   7
   8 /*
   9  * This file handles the architecture-dependent parts of process handling..
  10  */
  11
  12 #include <stdarg.h>
  13
  14 #include <linux/errno.h>
  15 #include <linux/module.h>
  16 #include <linux/sched.h>
  17 #include <linux/kernel.h>
  18 #include <linux/kallsyms.h>
  19 #include <linux/mm.h>
  20 #include <linux/stddef.h>
  21 #include <linux/ptrace.h>
  22 #include <linux/slab.h>
  23 #include <linux/user.h>
  24 #include <linux/a.out.h>
  25 #include <linux/config.h>
  26 #include <linux/smp.h>
  27 #include <linux/smp_lock.h>
  28 #include <linux/reboot.h>
  29 #include <linux/delay.h>
  30 #include <linux/pm.h>
  31 #include <linux/init.h>
  32
  33 #include <asm/auxio.h>
  34 #include <asm/oplib.h>
  35 #include <asm/uaccess.h>
  36 #include <asm/system.h>
  37 #include <asm/page.h>
  38 #include <asm/pgalloc.h>
  39 #include <asm/pgtable.h>
  40 #include <asm/delay.h>
  41 #include <asm/processor.h>
  42 #include <asm/psr.h>
  43 #include <asm/elf.h>
  44 #include <asm/unistd.h>
  45
  46 /*
  47  * Power management idle function
  48  * Set in pm platform drivers (apc.c and pmc.c)
  49  */
  50 void (*pm_idle)(void);
  51
  52 /*
  53  * Power-off handler instantiation for pm.h compliance
  54  * This is done via auxio, but could be used as a fallback
  55  * handler when auxio is not present-- unused for now...
  56  */
  57 void (*pm_power_off)(void);
  58
  59 /*
  60  * sysctl - toggle power-off restriction for serial console
  61  * systems in machine_power_off()
  62  */
  63 int scons_pwroff = 1;
  64
  65 extern void fpsave(unsigned long *, unsigned long *, void *, unsigned long *);
  66
  67 struct task_struct *last_task_used_math = NULL;
  68 struct thread_info *current_set[NR_CPUS];
  69
  70 /*
  71  * default_idle is new in 2.5. XXX Review, currently stolen from sparc64.
  72  */
  73 void default_idle(void)
  74 {
  75 }
  76
  77 #ifndef CONFIG_SMP
  78
  79 #define SUN4C_FAULT_HIGH 100
  80
  81 /*
  82  * the idle loop on a Sparc... ;)
  83  */
  84 void cpu_idle(void)
  85 {
  86         if (current->pid != 0)
  87                 goto out;
  88
  89         /* endless idle loop with no priority at all */
  90         for (;;) {
  91                 if (ARCH_SUN4C_SUN4) {
  92                         static int count = HZ;
  93                         static unsigned long last_jiffies;
  94                         static unsigned long last_faults;
  95                         static unsigned long fps;
  96                         unsigned long now;
  97                         unsigned long faults;
  98                         unsigned long flags;
  99
 100                         extern unsigned long sun4c_kernel_faults;
 101                         extern void sun4c_grow_kernel_ring(void);
 102
 103                         local_irq_save(flags);
 104                         now = jiffies;
 105                         count -= (now - last_jiffies);
 106                         last_jiffies = now;
 107                         if (count < 0) {
 108                                 count += HZ;
 109                                 faults = sun4c_kernel_faults;
 110                                 fps = (fps + (faults - last_faults)) >> 1;
 111                                 last_faults = faults;
 112 #if 0
 113                                 printk("kernel faults / second = %ld\n", fps);
 114 #endif
 115                                 if (fps >= SUN4C_FAULT_HIGH) {
 116                                         sun4c_grow_kernel_ring();
 117                                 }
 118                         }
 119                         local_irq_restore(flags);
 120                 }
 121
 122                 while((!need_resched()) && pm_idle) {
 123                         (*pm_idle)();
 124                 }
 125
 126                 schedule();
 127                 check_pgt_cache();
 128         }
 129 out:
 130         return;
 131 }
 132
 133 #else
 134
 135 /* This is being executed in task 0 'user space'. */
 136 void cpu_idle(void)
 137 {
 138         /* endless idle loop with no priority at all */
 139         while(1) {
 140                 if(need_resched()) {
 141                         schedule();
 142                         check_pgt_cache();
 143                 }
 144                 barrier(); /* or else gcc optimizes... */
 145         }
 146 }
 147
 148 #endif
 149
 150 extern char reboot_command [];
 151
 152 extern void (*prom_palette)(int);
 153
 154 /* XXX cli/sti -> local_irq_xxx here, check this works once SMP is fixed. */
 155 void machine_halt(void)
 156 {
 157         local_irq_enable();
 158         mdelay(8);
 159         local_irq_disable();
 160         if (!serial_console && prom_palette)
 161                 prom_palette (1);
 162         prom_halt();
 163         panic("Halt failed!");
 164 }
 165
 166 EXPORT_SYMBOL(machine_halt);
 167
 168 void machine_restart(char * cmd)
 169 {
 170         char *p;
 171
 172         local_irq_enable();
 173         mdelay(8);
 174         local_irq_disable();
 175
 176         p = strchr (reboot_command, '\n');
 177         if (p) *p = 0;
 178         if (!serial_console && prom_palette)
 179                 prom_palette (1);
 180         if (cmd)
 181                 prom_reboot(cmd);
 182         if (*reboot_command)
 183                 prom_reboot(reboot_command);
 184         prom_feval ("reset");
 185         panic("Reboot failed!");
 186 }
 187
 188 EXPORT_SYMBOL(machine_restart);
 189
 190 void machine_power_off(void)
 191 {
 192 #ifdef CONFIG_SUN_AUXIO
 193         if (auxio_power_register && (!serial_console || scons_pwroff))
 194                 *auxio_power_register |= AUXIO_POWER_OFF;
 195 #endif
 196         machine_halt();
 197 }
 198
 199 EXPORT_SYMBOL(machine_power_off);
 200
 201 static DEFINE_SPINLOCK(sparc_backtrace_lock);
 202
 203 void __show_backtrace(unsigned long fp)
 204 {
 205         struct reg_window *rw;
 206         unsigned long flags;
 207         int cpu = smp_processor_id();
 208
 209         spin_lock_irqsave(&sparc_backtrace_lock, flags);
 210
 211         rw = (struct reg_window *)fp;
 212         while(rw && (((unsigned long) rw) >= PAGE_OFFSET) &&
 213             !(((unsigned long) rw) & 0x7)) {
 214                 printk("CPU[%d]: ARGS[%08lx,%08lx,%08lx,%08lx,%08lx,%08lx] "
 215                        "FP[%08lx] CALLER[%08lx]: ", cpu,
 216                        rw->ins[0], rw->ins[1], rw->ins[2], rw->ins[3],
 217                        rw->ins[4], rw->ins[5],
 218                        rw->ins[6],
 219                        rw->ins[7]);
 220                 print_symbol("%s\n", rw->ins[7]);
 221                 rw = (struct reg_window *) rw->ins[6];
 222         }
 223         spin_unlock_irqrestore(&sparc_backtrace_lock, flags);
 224 }
 225
 226 #define __SAVE __asm__ __volatile__("save %sp, -0x40, %sp\n\t")
 227 #define __RESTORE __asm__ __volatile__("restore %g0, %g0, %g0\n\t")
 228 #define __GET_FP(fp) __asm__ __volatile__("mov %%i6, %0" : "=r" (fp))
 229
 230 void show_backtrace(void)
 231 {
 232         unsigned long fp;
 233
 234         __SAVE; __SAVE; __SAVE; __SAVE;
 235         __SAVE; __SAVE; __SAVE; __SAVE;
 236         __RESTORE; __RESTORE; __RESTORE; __RESTORE;
 237         __RESTORE; __RESTORE; __RESTORE; __RESTORE;
 238
 239         __GET_FP(fp);
 240
 241         __show_backtrace(fp);
 242 }
 243
 244 #ifdef CONFIG_SMP
 245 void smp_show_backtrace_all_cpus(void)
 246 {
 247         xc0((smpfunc_t) show_backtrace);
 248         show_backtrace();
 249 }
 250 #endif
 251
 252 #if 0
 253 void show_stackframe(struct sparc_stackf *sf)
 254 {
 255         unsigned long size;
 256         unsigned long *stk;
 257         int i;
 258
 259         printk("l0: %08lx l1: %08lx l2: %08lx l3: %08lx "
 260                "l4: %08lx l5: %08lx l6: %08lx l7: %08lx\n",
 261                sf->locals[0], sf->locals[1], sf->locals[2], sf->locals[3],
 262                sf->locals[4], sf->locals[5], sf->locals[6], sf->locals[7]);
 263         printk("i0: %08lx i1: %08lx i2: %08lx i3: %08lx "
 264                "i4: %08lx i5: %08lx fp: %08lx i7: %08lx\n",
 265                sf->ins[0], sf->ins[1], sf->ins[2], sf->ins[3],
 266                sf->ins[4], sf->ins[5], (unsigned long)sf->fp, sf->callers_pc);
 267         printk("sp: %08lx x0: %08lx x1: %08lx x2: %08lx "
 268                "x3: %08lx x4: %08lx x5: %08lx xx: %08lx\n",
 269                (unsigned long)sf->structptr, sf->xargs[0], sf->xargs[1],
 270                sf->xargs[2], sf->xargs[3], sf->xargs[4], sf->xargs[5],
 271                sf->xxargs[0]);
 272         size = ((unsigned long)sf->fp) - ((unsigned long)sf);
 273         size -= STACKFRAME_SZ;
 274         stk = (unsigned long *)((unsigned long)sf + STACKFRAME_SZ);
 275         i = 0;
 276         do {
 277                 printk("s%d: %08lx\n", i++, *stk++);
 278         } while ((size -= sizeof(unsigned long)));
 279 }
 280 #endif
 281
 282 void show_regs(struct pt_regs *r)
 283 {
 284         struct reg_window *rw = (struct reg_window *) r->u_regs[14];
 285
 286         printk("PSR: %08lx PC: %08lx NPC: %08lx Y: %08lx    %s\n",
 287                r->psr, r->pc, r->npc, r->y, print_tainted());
 288         print_symbol("PC: <%s>\n", r->pc);
 289         printk("%%G: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",
 290                r->u_regs[0], r->u_regs[1], r->u_regs[2], r->u_regs[3],
 291                r->u_regs[4], r->u_regs[5], r->u_regs[6], r->u_regs[7]);
 292         printk("%%O: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",
 293                r->u_regs[8], r->u_regs[9], r->u_regs[10], r->u_regs[11],
 294                r->u_regs[12], r->u_regs[13], r->u_regs[14], r->u_regs[15]);
 295         print_symbol("RPC: <%s>\n", r->u_regs[15]);
 296
 297         printk("%%L: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",
 298                rw->locals[0], rw->locals[1], rw->locals[2], rw->locals[3],
 299                rw->locals[4], rw->locals[5], rw->locals[6], rw->locals[7]);
 300         printk("%%I: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",
 301                rw->ins[0], rw->ins[1], rw->ins[2], rw->ins[3],
 302                rw->ins[4], rw->ins[5], rw->ins[6], rw->ins[7]);
 303 }
 304
 305 /*
 306  * The show_stack is an external API which we do not use ourselves.
 307  * The oops is printed in die_if_kernel.
 308  */
 309 void show_stack(struct task_struct *tsk, unsigned long *_ksp)
 310 {
 311         unsigned long pc, fp;
 312         unsigned long task_base;
 313         struct reg_window *rw;
 314         int count = 0;
 315
 316         if (tsk != NULL)
 317                 task_base = (unsigned long) tsk->thread_info;
 318         else
 319                 task_base = (unsigned long) current_thread_info();
 320
 321         fp = (unsigned long) _ksp;
 322         do {
 323                 /* Bogus frame pointer? */
 324                 if (fp < (task_base + sizeof(struct thread_info)) ||
 325                     fp >= (task_base + (PAGE_SIZE << 1)))
 326                         break;
 327                 rw = (struct reg_window *) fp;
 328                 pc = rw->ins[7];
 329                 printk("[%08lx : ", pc);
 330                 print_symbol("%s ] ", pc);
 331                 fp = rw->ins[6];
 332         } while (++count < 16);
 333         printk("\n");
 334 }
 335
 336 /*
 337  * Note: sparc64 has a pretty intricated thread_saved_pc, check it out.
 338  */
 339 unsigned long thread_saved_pc(struct task_struct *tsk)
 340 {
 341         return tsk->thread_info->kpc;
 342 }
 343
 344 /*
 345  * Free current thread data structures etc..
 346  */
 347 void exit_thread(void)
 348 {
 349 #ifndef CONFIG_SMP
 350         if(last_task_used_math == current) {
 351 #else
 352         if(current_thread_info()->flags & _TIF_USEDFPU) {
 353 #endif
 354                 /* Keep process from leaving FPU in a bogon state. */
 355                 put_psr(get_psr() | PSR_EF);
 356                 fpsave(&current->thread.float_regs[0], &current->thread.fsr,
 357                        &current->thread.fpqueue[0], &current->thread.fpqdepth);
 358 #ifndef CONFIG_SMP
 359                 last_task_used_math = NULL;
 360 #else
 361                 current_thread_info()->flags &= ~_TIF_USEDFPU;
 362 #endif
 363         }
 364 }
 365
 366 void flush_thread(void)
 367 {
 368         current_thread_info()->w_saved = 0;
 369
 370         /* No new signal delivery by default */
 371         current->thread.new_signal = 0;
 372 #ifndef CONFIG_SMP
 373         if(last_task_used_math == current) {
 374 #else
 375         if(current_thread_info()->flags & _TIF_USEDFPU) {
 376 #endif
 377                 /* Clean the fpu. */
 378                 put_psr(get_psr() | PSR_EF);
 379                 fpsave(&current->thread.float_regs[0], &current->thread.fsr,
 380                        &current->thread.fpqueue[0], &current->thread.fpqdepth);
 381 #ifndef CONFIG_SMP
 382                 last_task_used_math = NULL;
 383 #else
 384                 current_thread_info()->flags &= ~_TIF_USEDFPU;
 385 #endif
 386         }
 387
 388         /* Now, this task is no longer a kernel thread. */
 389         current->thread.current_ds = USER_DS;
 390         if (current->thread.flags & SPARC_FLAG_KTHREAD) {
 391                 current->thread.flags &= ~SPARC_FLAG_KTHREAD;
 392
 393                 /* We must fixup kregs as well. */
 394                 /* XXX This was not fixed for ti for a while, worked. Unused? */
 395                 current->thread.kregs = (struct pt_regs *)
 396                     ((char *)current->thread_info + (THREAD_SIZE - TRACEREG_SZ));
 397         }
 398 }
 399
 400 static __inline__ struct sparc_stackf __user *
 401 clone_stackframe(struct sparc_stackf __user *dst,
 402                  struct sparc_stackf __user *src)
 403 {
 404         unsigned long size, fp;
 405         struct sparc_stackf *tmp;
 406         struct sparc_stackf __user *sp;
 407
 408         if (get_user(tmp, &src->fp))
 409                 return NULL;
 410
 411         fp = (unsigned long) tmp;
 412         size = (fp - ((unsigned long) src));
 413         fp = (unsigned long) dst;
 414         sp = (struct sparc_stackf __user *)(fp - size);
 415
 416         /* do_fork() grabs the parent semaphore, we must release it
 417          * temporarily so we can build the child clone stack frame
 418          * without deadlocking.
 419          */
 420         if (__copy_user(sp, src, size))
 421                 sp = NULL;
 422         else if (put_user(fp, &sp->fp))
 423                 sp = NULL;
 424
 425         return sp;
 426 }
 427
 428 asmlinkage int sparc_do_fork(unsigned long clone_flags,
 429                              unsigned long stack_start,
 430                              struct pt_regs *regs,
 431                              unsigned long stack_size)
 432 {
 433         unsigned long parent_tid_ptr, child_tid_ptr;
 434
 435         parent_tid_ptr = regs->u_regs[UREG_I2];
 436         child_tid_ptr = regs->u_regs[UREG_I4];
 437
 438         return do_fork(clone_flags, stack_start,
 439                        regs, stack_size,
 440                        (int __user *) parent_tid_ptr,
 441                        (int __user *) child_tid_ptr);
 442 }
 443
 444 /* Copy a Sparc thread.  The fork() return value conventions
 445  * under SunOS are nothing short of bletcherous:
 446  * Parent -->  %o0 == childs  pid, %o1 == 0
 447  * Child  -->  %o0 == parents pid, %o1 == 1
 448  *
 449  * NOTE: We have a separate fork kpsr/kwim because
 450  *       the parent could change these values between
 451  *       sys_fork invocation and when we reach here
 452  *       if the parent should sleep while trying to
 453  *       allocate the task_struct and kernel stack in
 454  *       do_fork().
 455  * XXX See comment above sys_vfork in sparc64. todo.
 456  */
 457 extern void ret_from_fork(void);
 458
 459 int copy_thread(int nr, unsigned long clone_flags, unsigned long sp,
 460                 unsigned long unused,
 461                 struct task_struct *p, struct pt_regs *regs)
 462 {
 463         struct thread_info *ti = p->thread_info;
 464         struct pt_regs *childregs;
 465         char *new_stack;
 466
 467 #ifndef CONFIG_SMP
 468         if(last_task_used_math == current) {
 469 #else
 470         if(current_thread_info()->flags & _TIF_USEDFPU) {
 471 #endif
 472                 put_psr(get_psr() | PSR_EF);
 473                 fpsave(&p->thread.float_regs[0], &p->thread.fsr,
 474                        &p->thread.fpqueue[0], &p->thread.fpqdepth);
 475 #ifdef CONFIG_SMP
 476                 current_thread_info()->flags &= ~_TIF_USEDFPU;
 477 #endif
 478         }
 479
 480         /*
 481          *  p->thread_info         new_stack   childregs
 482          *  !                      !           !             {if(PSR_PS) }
 483          *  V                      V (stk.fr.) V  (pt_regs)  { (stk.fr.) }
 484          *  +----- - - - - - ------+===========+============={+==========}+
 485          */
 486         new_stack = (char*)ti + THREAD_SIZE;
 487         if (regs->psr & PSR_PS)
 488                 new_stack -= STACKFRAME_SZ;
 489         new_stack -= STACKFRAME_SZ + TRACEREG_SZ;
 490         memcpy(new_stack, (char *)regs - STACKFRAME_SZ, STACKFRAME_SZ + TRACEREG_SZ);
 491         childregs = (struct pt_regs *) (new_stack + STACKFRAME_SZ);
 492
 493         /*
 494          * A new process must start with interrupts closed in 2.5,
 495          * because this is how Mingo's scheduler works (see schedule_tail
 496          * and finish_arch_switch). If we do not do it, a timer interrupt hits
 497          * before we unlock, attempts to re-take the rq->lock, and then we die.
 498          * Thus, kpsr|=PSR_PIL.
 499          */
 500         ti->ksp = (unsigned long) new_stack;
 501         ti->kpc = (((unsigned long) ret_from_fork) - 0x8);
 502         ti->kpsr = current->thread.fork_kpsr | PSR_PIL;
 503         ti->kwim = current->thread.fork_kwim;
 504
 505         if(regs->psr & PSR_PS) {
 506                 extern struct pt_regs fake_swapper_regs;
 507
 508                 p->thread.kregs = &fake_swapper_regs;
 509                 new_stack += STACKFRAME_SZ + TRACEREG_SZ;
 510                 childregs->u_regs[UREG_FP] = (unsigned long) new_stack;
 511                 p->thread.flags |= SPARC_FLAG_KTHREAD;
 512                 p->thread.current_ds = KERNEL_DS;
 513                 memcpy(new_stack, (void *)regs->u_regs[UREG_FP], STACKFRAME_SZ);
 514                 childregs->u_regs[UREG_G6] = (unsigned long) ti;
 515         } else {
 516                 p->thread.kregs = childregs;
 517                 childregs->u_regs[UREG_FP] = sp;
 518                 p->thread.flags &= ~SPARC_FLAG_KTHREAD;
 519                 p->thread.current_ds = USER_DS;
 520
 521                 if (sp != regs->u_regs[UREG_FP]) {
 522                         struct sparc_stackf __user *childstack;
 523                         struct sparc_stackf __user *parentstack;
 524
 525                         /*
 526                          * This is a clone() call with supplied user stack.
 527                          * Set some valid stack frames to give to the child.
 528                          */
 529                         childstack = (struct sparc_stackf __user *)
 530                                 (sp & ~0x7UL);
 531                         parentstack = (struct sparc_stackf __user *)
 532                                 regs->u_regs[UREG_FP];
 533
 534 #if 0
 535                         printk("clone: parent stack:\n");
 536                         show_stackframe(parentstack);
 537 #endif
 538
 539                         childstack = clone_stackframe(childstack, parentstack);
 540                         if (!childstack)
 541                                 return -EFAULT;
 542
 543 #if 0
 544                         printk("clone: child stack:\n");
 545                         show_stackframe(childstack);
 546 #endif
 547
 548                         childregs->u_regs[UREG_FP] = (unsigned long)childstack;
 549                 }
 550         }
 551
 552 #ifdef CONFIG_SMP
 553         /* FPU must be disabled on SMP. */
 554         childregs->psr &= ~PSR_EF;
 555 #endif
 556
 557         /* Set the return value for the child. */
 558         childregs->u_regs[UREG_I0] = current->pid;
 559         childregs->u_regs[UREG_I1] = 1;
 560
 561         /* Set the return value for the parent. */
 562         regs->u_regs[UREG_I1] = 0;
 563
 564         if (clone_flags & CLONE_SETTLS)
 565                 childregs->u_regs[UREG_G7] = regs->u_regs[UREG_I3];
 566
 567         return 0;
 568 }
 569
 570 /*
 571  * fill in the user structure for a core dump..
 572  */
 573 void dump_thread(struct pt_regs * regs, struct user * dump)
 574 {
 575         unsigned long first_stack_page;
 576
 577         dump->magic = SUNOS_CORE_MAGIC;
 578         dump->len = sizeof(struct user);
 579         dump->regs.psr = regs->psr;
 580         dump->regs.pc = regs->pc;
 581         dump->regs.npc = regs->npc;
 582         dump->regs.y = regs->y;
 583         /* fuck me plenty */
 584         memcpy(&dump->regs.regs[0], &regs->u_regs[1], (sizeof(unsigned long) * 15));
 585         dump->uexec = current->thread.core_exec;
 586         dump->u_tsize = (((unsigned long) current->mm->end_code) -
 587                 ((unsigned long) current->mm->start_code)) & ~(PAGE_SIZE - 1);
 588         dump->u_dsize = ((unsigned long) (current->mm->brk + (PAGE_SIZE-1)));
 589         dump->u_dsize -= dump->u_tsize;
 590         dump->u_dsize &= ~(PAGE_SIZE - 1);
 591         first_stack_page = (regs->u_regs[UREG_FP] & ~(PAGE_SIZE - 1));
 592         dump->u_ssize = (TASK_SIZE - first_stack_page) & ~(PAGE_SIZE - 1);
 593         memcpy(&dump->fpu.fpstatus.fregs.regs[0], &current->thread.float_regs[0], (sizeof(unsigned long) * 32));
 594         dump->fpu.fpstatus.fsr = current->thread.fsr;
 595         dump->fpu.fpstatus.flags = dump->fpu.fpstatus.extra = 0;
 596         dump->fpu.fpstatus.fpq_count = current->thread.fpqdepth;
 597         memcpy(&dump->fpu.fpstatus.fpq[0], &current->thread.fpqueue[0],
 598                ((sizeof(unsigned long) * 2) * 16));
 599         dump->sigcode = 0;
 600 }
 601
 602 /*
 603  * fill in the fpu structure for a core dump.
 604  */
 605 int dump_fpu (struct pt_regs * regs, elf_fpregset_t * fpregs)
 606 {
 607         if (used_math()) {
 608                 memset(fpregs, 0, sizeof(*fpregs));
 609                 fpregs->pr_q_entrysize = 8;
 610                 return 1;
 611         }
 612 #ifdef CONFIG_SMP
 613         if (current_thread_info()->flags & _TIF_USEDFPU) {
 614                 put_psr(get_psr() | PSR_EF);
 615                 fpsave(&current->thread.float_regs[0], &current->thread.fsr,
 616                        &current->thread.fpqueue[0], &current->thread.fpqdepth);
 617                 if (regs != NULL) {
 618                         regs->psr &= ~(PSR_EF);
 619                         current_thread_info()->flags &= ~(_TIF_USEDFPU);
 620                 }
 621         }
 622 #else
 623         if (current == last_task_used_math) {
 624                 put_psr(get_psr() | PSR_EF);
 625                 fpsave(&current->thread.float_regs[0], &current->thread.fsr,
 626                        &current->thread.fpqueue[0], &current->thread.fpqdepth);
 627                 if (regs != NULL) {
 628                         regs->psr &= ~(PSR_EF);
 629                         last_task_used_math = NULL;
 630                 }
 631         }
 632 #endif
 633         memcpy(&fpregs->pr_fr.pr_regs[0],
 634                &current->thread.float_regs[0],
 635                (sizeof(unsigned long) * 32));
 636         fpregs->pr_fsr = current->thread.fsr;
 637         fpregs->pr_qcnt = current->thread.fpqdepth;
 638         fpregs->pr_q_entrysize = 8;
 639         fpregs->pr_en = 1;
 640         if(fpregs->pr_qcnt != 0) {
 641                 memcpy(&fpregs->pr_q[0],
 642                        &current->thread.fpqueue[0],
 643                        sizeof(struct fpq) * fpregs->pr_qcnt);
 644         }
 645         /* Zero out the rest. */
 646         memset(&fpregs->pr_q[fpregs->pr_qcnt], 0,
 647                sizeof(struct fpq) * (32 - fpregs->pr_qcnt));
 648         return 1;
 649 }
 650
 651 /*
 652  * sparc_execve() executes a new program after the asm stub has set
 653  * things up for us.  This should basically do what I want it to.
 654  */
 655 asmlinkage int sparc_execve(struct pt_regs *regs)
 656 {
 657         int error, base = 0;
 658         char *filename;
 659
 660         /* Check for indirect call. */
 661         if(regs->u_regs[UREG_G1] == 0)
 662                 base = 1;
 663
 664         filename = getname((char __user *)regs->u_regs[base + UREG_I0]);
 665         error = PTR_ERR(filename);
 666         if(IS_ERR(filename))
 667                 goto out;
 668         error = do_execve(filename,
 669                           (char __user * __user *)regs->u_regs[base + UREG_I1],
 670                           (char __user * __user *)regs->u_regs[base + UREG_I2],
 671                           regs);
 672         putname(filename);
 673         if (error == 0) {
 674                 task_lock(current);
 675                 current->ptrace &= ~PT_DTRACE;
 676                 task_unlock(current);
 677         }
 678 out:
 679         return error;
 680 }
 681
 682 /*
 683  * This is the mechanism for creating a new kernel thread.
 684  *
 685  * NOTE! Only a kernel-only process(ie the swapper or direct descendants
 686  * who haven't done an "execve()") should use this: it will work within
 687  * a system call from a "real" process, but the process memory space will
 688  * not be free'd until both the parent and the child have exited.
 689  */
 690 pid_t kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
 691 {
 692         long retval;
 693
 694         __asm__ __volatile__("mov %4, %%g2\n\t"    /* Set aside fn ptr... */
 695                              "mov %5, %%g3\n\t"    /* and arg. */
 696                              "mov %1, %%g1\n\t"
 697                              "mov %2, %%o0\n\t"    /* Clone flags. */
 698                              "mov 0, %%o1\n\t"     /* usp arg == 0 */
 699                              "t 0x10\n\t"          /* Linux/Sparc clone(). */
 700                              "cmp %%o1, 0\n\t"
 701                              "be 1f\n\t"           /* The parent, just return. */
 702                              " nop\n\t"            /* Delay slot. */
 703                              "jmpl %%g2, %%o7\n\t" /* Call the function. */
 704                              " mov %%g3, %%o0\n\t" /* Get back the arg in delay. */
 705                              "mov %3, %%g1\n\t"
 706                              "t 0x10\n\t"          /* Linux/Sparc exit(). */
 707                              /* Notreached by child. */
 708                              "1: mov %%o0, %0\n\t" :
 709                              "=r" (retval) :
 710                              "i" (__NR_clone), "r" (flags | CLONE_VM | CLONE_UNTRACED),
 711                              "i" (__NR_exit),  "r" (fn), "r" (arg) :
 712                              "g1", "g2", "g3", "o0", "o1", "memory", "cc");
 713         return retval;
 714 }
 715
 716 unsigned long get_wchan(struct task_struct *task)
 717 {
 718         unsigned long pc, fp, bias = 0;
 719         unsigned long task_base = (unsigned long) task;
 720         unsigned long ret = 0;
 721         struct reg_window *rw;
 722         int count = 0;
 723
 724         if (!task || task == current ||
 725             task->state == TASK_RUNNING)
 726                 goto out;
 727
 728         fp = task->thread_info->ksp + bias;
 729         do {
 730                 /* Bogus frame pointer? */
 731                 if (fp < (task_base + sizeof(struct thread_info)) ||
 732                     fp >= (task_base + (2 * PAGE_SIZE)))
 733                         break;
 734                 rw = (struct reg_window *) fp;
 735                 pc = rw->ins[7];
 736                 if (!in_sched_functions(pc)) {
 737                         ret = pc;
 738                         goto out;
 739                 }
 740                 fp = rw->ins[6] + bias;
 741         } while (++count < 16);
 742
 743 out:
 744         return ret;
 745 }
 746