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