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/slab.h>
  21 #include <linux/user.h>
  22 #include <linux/smp.h>
  23 #include <linux/reboot.h>
  24 #include <linux/delay.h>
  25 #include <linux/pm.h>
  26 #include <linux/init.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
  48 /*
  49  * Power-off handler instantiation for pm.h compliance
  50  * This is done via auxio, but could be used as a fallback
  51  * handler when auxio is not present-- unused for now...
  52  */
  53 void (*pm_power_off)(void) = machine_power_off;
  54 EXPORT_SYMBOL(pm_power_off);
  55
  56 /*
  57  * sysctl - toggle power-off restriction for serial console
  58  * systems in machine_power_off()
  59  */
  60 int scons_pwroff = 1;
  61
  62 extern void fpsave(unsigned long *, unsigned long *, void *, unsigned long *);
  63
  64 struct task_struct *last_task_used_math = NULL;
  65 struct thread_info *current_set[NR_CPUS];
  66
  67 #ifndef CONFIG_SMP
  68
  69 #define SUN4C_FAULT_HIGH 100
  70
  71 /*
  72  * the idle loop on a Sparc... ;)
  73  */
  74 void cpu_idle(void)
  75 {
  76         /* endless idle loop with no priority at all */
  77         for (;;) {
  78                 if (ARCH_SUN4C) {
  79                         static int count = HZ;
  80                         static unsigned long last_jiffies;
  81                         static unsigned long last_faults;
  82                         static unsigned long fps;
  83                         unsigned long now;
  84                         unsigned long faults;
  85
  86                         extern unsigned long sun4c_kernel_faults;
  87                         extern void sun4c_grow_kernel_ring(void);
  88
  89                         local_irq_disable();
  90                         now = jiffies;
  91                         count -= (now - last_jiffies);
  92                         last_jiffies = now;
  93                         if (count < 0) {
  94                                 count += HZ;
  95                                 faults = sun4c_kernel_faults;
  96                                 fps = (fps + (faults - last_faults)) >> 1;
  97                                 last_faults = faults;
  98 #if 0
  99                                 printk("kernel faults / second = %ld\n", fps);
 100 #endif
 101                                 if (fps >= SUN4C_FAULT_HIGH) {
 102                                         sun4c_grow_kernel_ring();
 103                                 }
 104                         }
 105                         local_irq_enable();
 106                 }
 107
 108                 if (pm_idle) {
 109                         while (!need_resched())
 110                                 (*pm_idle)();
 111                 } else {
 112                         while (!need_resched())
 113                                 cpu_relax();
 114                 }
 115                 preempt_enable_no_resched();
 116                 schedule();
 117                 preempt_disable();
 118                 check_pgt_cache();
 119         }
 120 }
 121
 122 #else
 123
 124 /* This is being executed in task 0 'user space'. */
 125 void cpu_idle(void)
 126 {
 127         set_thread_flag(TIF_POLLING_NRFLAG);
 128         /* endless idle loop with no priority at all */
 129         while(1) {
 130                 while (!need_resched())
 131                         cpu_relax();
 132                 preempt_enable_no_resched();
 133                 schedule();
 134                 preempt_disable();
 135                 check_pgt_cache();
 136         }
 137 }
 138
 139 #endif
 140
 141 /* XXX cli/sti -> local_irq_xxx here, check this works once SMP is fixed. */
 142 void machine_halt(void)
 143 {
 144         local_irq_enable();
 145         mdelay(8);
 146         local_irq_disable();
 147         prom_halt();
 148         panic("Halt failed!");
 149 }
 150
 151 void machine_restart(char * cmd)
 152 {
 153         char *p;
 154
 155         local_irq_enable();
 156         mdelay(8);
 157         local_irq_disable();
 158
 159         p = strchr (reboot_command, '\n');
 160         if (p) *p = 0;
 161         if (cmd)
 162                 prom_reboot(cmd);
 163         if (*reboot_command)
 164                 prom_reboot(reboot_command);
 165         prom_feval ("reset");
 166         panic("Reboot failed!");
 167 }
 168
 169 void machine_power_off(void)
 170 {
 171         if (auxio_power_register &&
 172             (strcmp(of_console_device->type, "serial") || scons_pwroff))
 173                 *auxio_power_register |= AUXIO_POWER_OFF;
 174         machine_halt();
 175 }
 176
 177 #if 0
 178
 179 static DEFINE_SPINLOCK(sparc_backtrace_lock);
 180
 181 void __show_backtrace(unsigned long fp)
 182 {
 183         struct reg_window32 *rw;
 184         unsigned long flags;
 185         int cpu = smp_processor_id();
 186
 187         spin_lock_irqsave(&sparc_backtrace_lock, flags);
 188
 189         rw = (struct reg_window32 *)fp;
 190         while(rw && (((unsigned long) rw) >= PAGE_OFFSET) &&
 191             !(((unsigned long) rw) & 0x7)) {
 192                 printk("CPU[%d]: ARGS[%08lx,%08lx,%08lx,%08lx,%08lx,%08lx] "
 193                        "FP[%08lx] CALLER[%08lx]: ", cpu,
 194                        rw->ins[0], rw->ins[1], rw->ins[2], rw->ins[3],
 195                        rw->ins[4], rw->ins[5],
 196                        rw->ins[6],
 197                        rw->ins[7]);
 198                 printk("%pS\n", (void *) rw->ins[7]);
 199                 rw = (struct reg_window32 *) rw->ins[6];
 200         }
 201         spin_unlock_irqrestore(&sparc_backtrace_lock, flags);
 202 }
 203
 204 #define __SAVE __asm__ __volatile__("save %sp, -0x40, %sp\n\t")
 205 #define __RESTORE __asm__ __volatile__("restore %g0, %g0, %g0\n\t")
 206 #define __GET_FP(fp) __asm__ __volatile__("mov %%i6, %0" : "=r" (fp))
 207
 208 void show_backtrace(void)
 209 {
 210         unsigned long fp;
 211
 212         __SAVE; __SAVE; __SAVE; __SAVE;
 213         __SAVE; __SAVE; __SAVE; __SAVE;
 214         __RESTORE; __RESTORE; __RESTORE; __RESTORE;
 215         __RESTORE; __RESTORE; __RESTORE; __RESTORE;
 216
 217         __GET_FP(fp);
 218
 219         __show_backtrace(fp);
 220 }
 221
 222 #ifdef CONFIG_SMP
 223 void smp_show_backtrace_all_cpus(void)
 224 {
 225         xc0((smpfunc_t) show_backtrace);
 226         show_backtrace();
 227 }
 228 #endif
 229
 230 void show_stackframe(struct sparc_stackf *sf)
 231 {
 232         unsigned long size;
 233         unsigned long *stk;
 234         int i;
 235
 236         printk("l0: %08lx l1: %08lx l2: %08lx l3: %08lx "
 237                "l4: %08lx l5: %08lx l6: %08lx l7: %08lx\n",
 238                sf->locals[0], sf->locals[1], sf->locals[2], sf->locals[3],
 239                sf->locals[4], sf->locals[5], sf->locals[6], sf->locals[7]);
 240         printk("i0: %08lx i1: %08lx i2: %08lx i3: %08lx "
 241                "i4: %08lx i5: %08lx fp: %08lx i7: %08lx\n",
 242                sf->ins[0], sf->ins[1], sf->ins[2], sf->ins[3],
 243                sf->ins[4], sf->ins[5], (unsigned long)sf->fp, sf->callers_pc);
 244         printk("sp: %08lx x0: %08lx x1: %08lx x2: %08lx "
 245                "x3: %08lx x4: %08lx x5: %08lx xx: %08lx\n",
 246                (unsigned long)sf->structptr, sf->xargs[0], sf->xargs[1],
 247                sf->xargs[2], sf->xargs[3], sf->xargs[4], sf->xargs[5],
 248                sf->xxargs[0]);
 249         size = ((unsigned long)sf->fp) - ((unsigned long)sf);
 250         size -= STACKFRAME_SZ;
 251         stk = (unsigned long *)((unsigned long)sf + STACKFRAME_SZ);
 252         i = 0;
 253         do {
 254                 printk("s%d: %08lx\n", i++, *stk++);
 255         } while ((size -= sizeof(unsigned long)));
 256 }
 257 #endif
 258
 259 void show_regs(struct pt_regs *r)
 260 {
 261         struct reg_window32 *rw = (struct reg_window32 *) r->u_regs[14];
 262
 263         printk("PSR: %08lx PC: %08lx NPC: %08lx Y: %08lx    %s\n",
 264                r->psr, r->pc, r->npc, r->y, print_tainted());
 265         printk("PC: <%pS>\n", (void *) r->pc);
 266         printk("%%G: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",
 267                r->u_regs[0], r->u_regs[1], r->u_regs[2], r->u_regs[3],
 268                r->u_regs[4], r->u_regs[5], r->u_regs[6], r->u_regs[7]);
 269         printk("%%O: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",
 270                r->u_regs[8], r->u_regs[9], r->u_regs[10], r->u_regs[11],
 271                r->u_regs[12], r->u_regs[13], r->u_regs[14], r->u_regs[15]);
 272         printk("RPC: <%pS>\n", (void *) r->u_regs[15]);
 273
 274         printk("%%L: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",
 275                rw->locals[0], rw->locals[1], rw->locals[2], rw->locals[3],
 276                rw->locals[4], rw->locals[5], rw->locals[6], rw->locals[7]);
 277         printk("%%I: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",
 278                rw->ins[0], rw->ins[1], rw->ins[2], rw->ins[3],
 279                rw->ins[4], rw->ins[5], rw->ins[6], rw->ins[7]);
 280 }
 281
 282 /*
 283  * The show_stack is an external API which we do not use ourselves.
 284  * The oops is printed in die_if_kernel.
 285  */
 286 void show_stack(struct task_struct *tsk, unsigned long *_ksp)
 287 {
 288         unsigned long pc, fp;
 289         unsigned long task_base;
 290         struct reg_window32 *rw;
 291         int count = 0;
 292
 293         if (tsk != NULL)
 294                 task_base = (unsigned long) task_stack_page(tsk);
 295         else
 296                 task_base = (unsigned long) current_thread_info();
 297
 298         fp = (unsigned long) _ksp;
 299         do {
 300                 /* Bogus frame pointer? */
 301                 if (fp < (task_base + sizeof(struct thread_info)) ||
 302                     fp >= (task_base + (PAGE_SIZE << 1)))
 303                         break;
 304                 rw = (struct reg_window32 *) fp;
 305                 pc = rw->ins[7];
 306                 printk("[%08lx : ", pc);
 307                 printk("%pS ] ", (void *) pc);
 308                 fp = rw->ins[6];
 309         } while (++count < 16);
 310         printk("\n");
 311 }
 312
 313 void dump_stack(void)
 314 {
 315         unsigned long *ksp;
 316
 317         __asm__ __volatile__("mov       %%fp, %0"
 318                              : "=r" (ksp));
 319         show_stack(current, ksp);
 320 }
 321
 322 EXPORT_SYMBOL(dump_stack);
 323
 324 /*
 325  * Note: sparc64 has a pretty intricated thread_saved_pc, check it out.
 326  */
 327 unsigned long thread_saved_pc(struct task_struct *tsk)
 328 {
 329         return task_thread_info(tsk)->kpc;
 330 }
 331
 332 /*
 333  * Free current thread data structures etc..
 334  */
 335 void exit_thread(void)
 336 {
 337 #ifndef CONFIG_SMP
 338         if(last_task_used_math == current) {
 339 #else
 340         if (test_thread_flag(TIF_USEDFPU)) {
 341 #endif
 342                 /* Keep process from leaving FPU in a bogon state. */
 343                 put_psr(get_psr() | PSR_EF);
 344                 fpsave(&current->thread.float_regs[0], &current->thread.fsr,
 345                        &current->thread.fpqueue[0], &current->thread.fpqdepth);
 346 #ifndef CONFIG_SMP
 347                 last_task_used_math = NULL;
 348 #else
 349                 clear_thread_flag(TIF_USEDFPU);
 350 #endif
 351         }
 352 }
 353
 354 void flush_thread(void)
 355 {
 356         current_thread_info()->w_saved = 0;
 357
 358 #ifndef CONFIG_SMP
 359         if(last_task_used_math == current) {
 360 #else
 361         if (test_thread_flag(TIF_USEDFPU)) {
 362 #endif
 363                 /* Clean the fpu. */
 364                 put_psr(get_psr() | PSR_EF);
 365                 fpsave(&current->thread.float_regs[0], &current->thread.fsr,
 366                        &current->thread.fpqueue[0], &current->thread.fpqdepth);
 367 #ifndef CONFIG_SMP
 368                 last_task_used_math = NULL;
 369 #else
 370                 clear_thread_flag(TIF_USEDFPU);
 371 #endif
 372         }
 373
 374         /* Now, this task is no longer a kernel thread. */
 375         current->thread.current_ds = USER_DS;
 376         if (current->thread.flags & SPARC_FLAG_KTHREAD) {
 377                 current->thread.flags &= ~SPARC_FLAG_KTHREAD;
 378
 379                 /* We must fixup kregs as well. */
 380                 /* XXX This was not fixed for ti for a while, worked. Unused? */
 381                 current->thread.kregs = (struct pt_regs *)
 382                     (task_stack_page(current) + (THREAD_SIZE - TRACEREG_SZ));
 383         }
 384 }
 385
 386 static inline struct sparc_stackf __user *
 387 clone_stackframe(struct sparc_stackf __user *dst,
 388                  struct sparc_stackf __user *src)
 389 {
 390         unsigned long size, fp;
 391         struct sparc_stackf *tmp;
 392         struct sparc_stackf __user *sp;
 393
 394         if (get_user(tmp, &src->fp))
 395                 return NULL;
 396
 397         fp = (unsigned long) tmp;
 398         size = (fp - ((unsigned long) src));
 399         fp = (unsigned long) dst;
 400         sp = (struct sparc_stackf __user *)(fp - size);
 401
 402         /* do_fork() grabs the parent semaphore, we must release it
 403          * temporarily so we can build the child clone stack frame
 404          * without deadlocking.
 405          */
 406         if (__copy_user(sp, src, size))
 407                 sp = NULL;
 408         else if (put_user(fp, &sp->fp))
 409                 sp = NULL;
 410
 411         return sp;
 412 }
 413
 414 asmlinkage int sparc_do_fork(unsigned long clone_flags,
 415                              unsigned long stack_start,
 416                              struct pt_regs *regs,
 417                              unsigned long stack_size)
 418 {
 419         unsigned long parent_tid_ptr, child_tid_ptr;
 420         unsigned long orig_i1 = regs->u_regs[UREG_I1];
 421         long ret;
 422
 423         parent_tid_ptr = regs->u_regs[UREG_I2];
 424         child_tid_ptr = regs->u_regs[UREG_I4];
 425
 426         ret = do_fork(clone_flags, stack_start,
 427                       regs, stack_size,
 428                       (int __user *) parent_tid_ptr,
 429                       (int __user *) child_tid_ptr);
 430
 431         /* If we get an error and potentially restart the system
 432          * call, we're screwed because copy_thread() clobbered
 433          * the parent's %o1.  So detect that case and restore it
 434          * here.
 435          */
 436         if ((unsigned long)ret >= -ERESTART_RESTARTBLOCK)
 437                 regs->u_regs[UREG_I1] = orig_i1;
 438
 439         return ret;
 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 fpu structure for a core dump.
 570  */
 571 int dump_fpu (struct pt_regs * regs, elf_fpregset_t * fpregs)
 572 {
 573         if (used_math()) {
 574                 memset(fpregs, 0, sizeof(*fpregs));
 575                 fpregs->pr_q_entrysize = 8;
 576                 return 1;
 577         }
 578 #ifdef CONFIG_SMP
 579         if (test_thread_flag(TIF_USEDFPU)) {
 580                 put_psr(get_psr() | PSR_EF);
 581                 fpsave(&current->thread.float_regs[0], &current->thread.fsr,
 582                        &current->thread.fpqueue[0], &current->thread.fpqdepth);
 583                 if (regs != NULL) {
 584                         regs->psr &= ~(PSR_EF);
 585                         clear_thread_flag(TIF_USEDFPU);
 586                 }
 587         }
 588 #else
 589         if (current == last_task_used_math) {
 590                 put_psr(get_psr() | PSR_EF);
 591                 fpsave(&current->thread.float_regs[0], &current->thread.fsr,
 592                        &current->thread.fpqueue[0], &current->thread.fpqdepth);
 593                 if (regs != NULL) {
 594                         regs->psr &= ~(PSR_EF);
 595                         last_task_used_math = NULL;
 596                 }
 597         }
 598 #endif
 599         memcpy(&fpregs->pr_fr.pr_regs[0],
 600                &current->thread.float_regs[0],
 601                (sizeof(unsigned long) * 32));
 602         fpregs->pr_fsr = current->thread.fsr;
 603         fpregs->pr_qcnt = current->thread.fpqdepth;
 604         fpregs->pr_q_entrysize = 8;
 605         fpregs->pr_en = 1;
 606         if(fpregs->pr_qcnt != 0) {
 607                 memcpy(&fpregs->pr_q[0],
 608                        &current->thread.fpqueue[0],
 609                        sizeof(struct fpq) * fpregs->pr_qcnt);
 610         }
 611         /* Zero out the rest. */
 612         memset(&fpregs->pr_q[fpregs->pr_qcnt], 0,
 613                sizeof(struct fpq) * (32 - fpregs->pr_qcnt));
 614         return 1;
 615 }
 616
 617 /*
 618  * sparc_execve() executes a new program after the asm stub has set
 619  * things up for us.  This should basically do what I want it to.
 620  */
 621 asmlinkage int sparc_execve(struct pt_regs *regs)
 622 {
 623         int error, base = 0;
 624         char *filename;
 625
 626         /* Check for indirect call. */
 627         if(regs->u_regs[UREG_G1] == 0)
 628                 base = 1;
 629
 630         filename = getname((char __user *)regs->u_regs[base + UREG_I0]);
 631         error = PTR_ERR(filename);
 632         if(IS_ERR(filename))
 633                 goto out;
 634         error = do_execve(filename,
 635                           (char __user * __user *)regs->u_regs[base + UREG_I1],
 636                           (char __user * __user *)regs->u_regs[base + UREG_I2],
 637                           regs);
 638         putname(filename);
 639 out:
 640         return error;
 641 }
 642
 643 /*
 644  * This is the mechanism for creating a new kernel thread.
 645  *
 646  * NOTE! Only a kernel-only process(ie the swapper or direct descendants
 647  * who haven't done an "execve()") should use this: it will work within
 648  * a system call from a "real" process, but the process memory space will
 649  * not be freed until both the parent and the child have exited.
 650  */
 651 pid_t kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
 652 {
 653         long retval;
 654
 655         __asm__ __volatile__("mov %4, %%g2\n\t"    /* Set aside fn ptr... */
 656                              "mov %5, %%g3\n\t"    /* and arg. */
 657                              "mov %1, %%g1\n\t"
 658                              "mov %2, %%o0\n\t"    /* Clone flags. */
 659                              "mov 0, %%o1\n\t"     /* usp arg == 0 */
 660                              "t 0x10\n\t"          /* Linux/Sparc clone(). */
 661                              "cmp %%o1, 0\n\t"
 662                              "be 1f\n\t"           /* The parent, just return. */
 663                              " nop\n\t"            /* Delay slot. */
 664                              "jmpl %%g2, %%o7\n\t" /* Call the function. */
 665                              " mov %%g3, %%o0\n\t" /* Get back the arg in delay. */
 666                              "mov %3, %%g1\n\t"
 667                              "t 0x10\n\t"          /* Linux/Sparc exit(). */
 668                              /* Notreached by child. */
 669                              "1: mov %%o0, %0\n\t" :
 670                              "=r" (retval) :
 671                              "i" (__NR_clone), "r" (flags | CLONE_VM | CLONE_UNTRACED),
 672                              "i" (__NR_exit),  "r" (fn), "r" (arg) :
 673                              "g1", "g2", "g3", "o0", "o1", "memory", "cc");
 674         return retval;
 675 }
 676
 677 unsigned long get_wchan(struct task_struct *task)
 678 {
 679         unsigned long pc, fp, bias = 0;
 680         unsigned long task_base = (unsigned long) task;
 681         unsigned long ret = 0;
 682         struct reg_window32 *rw;
 683         int count = 0;
 684
 685         if (!task || task == current ||
 686             task->state == TASK_RUNNING)
 687                 goto out;
 688
 689         fp = task_thread_info(task)->ksp + bias;
 690         do {
 691                 /* Bogus frame pointer? */
 692                 if (fp < (task_base + sizeof(struct thread_info)) ||
 693                     fp >= (task_base + (2 * PAGE_SIZE)))
 694                         break;
 695                 rw = (struct reg_window32 *) fp;
 696                 pc = rw->ins[7];
 697                 if (!in_sched_functions(pc)) {
 698                         ret = pc;
 699                         goto out;
 700                 }
 701                 fp = rw->ins[6] + bias;
 702         } while (++count < 16);
 703
 704 out:
 705         return ret;
 706 }
 707