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Linux 2.6.25-rc4
[linux-2.6/next.git] / arch / sparc / kernel / process.c
blob70c0dd22491d2a5e4d3e4aaf1ebdc72ec7ca855f
1 /* linux/arch/sparc/kernel/process.c
2 *
3 * Copyright (C) 1995 David S. Miller (davem@davemloft.net)
4 * Copyright (C) 1996 Eddie C. Dost (ecd@skynet.be)
5 */
6
7 /*
8 * This file handles the architecture-dependent parts of process handling..
9 */
10
11 #include <stdarg.h>
12
13 #include <linux/errno.h>
14 #include <linux/module.h>
15 #include <linux/sched.h>
16 #include <linux/kernel.h>
17 #include <linux/kallsyms.h>
18 #include <linux/mm.h>
19 #include <linux/stddef.h>
20 #include <linux/ptrace.h>
21 #include <linux/slab.h>
22 #include <linux/user.h>
23 #include <linux/smp.h>
24 #include <linux/reboot.h>
25 #include <linux/delay.h>
26 #include <linux/pm.h>
27 #include <linux/init.h>
28
29 #include <asm/auxio.h>
30 #include <asm/oplib.h>
31 #include <asm/uaccess.h>
32 #include <asm/system.h>
33 #include <asm/page.h>
34 #include <asm/pgalloc.h>
35 #include <asm/pgtable.h>
36 #include <asm/delay.h>
37 #include <asm/processor.h>
38 #include <asm/psr.h>
39 #include <asm/elf.h>
40 #include <asm/prom.h>
41 #include <asm/unistd.h>
42
43 /*
44 * Power management idle function
45 * Set in pm platform drivers (apc.c and pmc.c)
46 */
47 void (*pm_idle)(void);
48
49 /*
50 * Power-off handler instantiation for pm.h compliance
51 * This is done via auxio, but could be used as a fallback
52 * handler when auxio is not present-- unused for now...
53 */
54 void (*pm_power_off)(void) = machine_power_off;
55 EXPORT_SYMBOL(pm_power_off);
56
57 /*
58 * sysctl - toggle power-off restriction for serial console
59 * systems in machine_power_off()
60 */
61 int scons_pwroff = 1;
62
63 extern void fpsave(unsigned long *, unsigned long *, void *, unsigned long *);
64
65 struct task_struct *last_task_used_math = NULL;
66 struct thread_info *current_set[NR_CPUS];
67
68 #ifndef CONFIG_SMP
69
70 #define SUN4C_FAULT_HIGH 100
71
72 /*
73 * the idle loop on a Sparc... ;)
74 */
75 void cpu_idle(void)
76 {
77 /* endless idle loop with no priority at all */
78 for (;;) {
79 if (ARCH_SUN4C_SUN4) {
80 static int count = HZ;
81 static unsigned long last_jiffies;
82 static unsigned long last_faults;
83 static unsigned long fps;
84 unsigned long now;
85 unsigned long faults;
86
87 extern unsigned long sun4c_kernel_faults;
88 extern void sun4c_grow_kernel_ring(void);
89
90 local_irq_disable();
91 now = jiffies;
92 count -= (now - last_jiffies);
93 last_jiffies = now;
94 if (count < 0) {
95 count += HZ;
96 faults = sun4c_kernel_faults;
97 fps = (fps + (faults - last_faults)) >> 1;
98 last_faults = faults;
99 #if 0
100 printk("kernel faults / second = %ld\n", fps);
101 #endif
102 if (fps >= SUN4C_FAULT_HIGH) {
103 sun4c_grow_kernel_ring();
104 }
105 }
106 local_irq_enable();
107 }
108
109 if (pm_idle) {
110 while (!need_resched())
111 (*pm_idle)();
112 } else {
113 while (!need_resched())
114 cpu_relax();
115 }
116 preempt_enable_no_resched();
117 schedule();
118 preempt_disable();
119 check_pgt_cache();
120 }
121 }
122
123 #else
124
125 /* This is being executed in task 0 'user space'. */
126 void cpu_idle(void)
127 {
128 set_thread_flag(TIF_POLLING_NRFLAG);
129 /* endless idle loop with no priority at all */
130 while(1) {
131 while (!need_resched())
132 cpu_relax();
133 preempt_enable_no_resched();
134 schedule();
135 preempt_disable();
136 check_pgt_cache();
137 }
138 }
139
140 #endif
141
142 /* XXX cli/sti -> local_irq_xxx here, check this works once SMP is fixed. */
143 void machine_halt(void)
144 {
145 local_irq_enable();
146 mdelay(8);
147 local_irq_disable();
148 prom_halt();
149 panic("Halt failed!");
150 }
151
152 void machine_restart(char * cmd)
153 {
154 char *p;
155
156 local_irq_enable();
157 mdelay(8);
158 local_irq_disable();
159
160 p = strchr (reboot_command, '\n');
161 if (p) *p = 0;
162 if (cmd)
163 prom_reboot(cmd);
164 if (*reboot_command)
165 prom_reboot(reboot_command);
166 prom_feval ("reset");
167 panic("Reboot failed!");
168 }
169
170 void machine_power_off(void)
171 {
172 #ifdef CONFIG_SUN_AUXIO
173 if (auxio_power_register &&
174 (strcmp(of_console_device->type, "serial") || scons_pwroff))
175 *auxio_power_register |= AUXIO_POWER_OFF;
176 #endif
177 machine_halt();
178 }
179
180 static DEFINE_SPINLOCK(sparc_backtrace_lock);
181
182 void __show_backtrace(unsigned long fp)
183 {
184 struct reg_window *rw;
185 unsigned long flags;
186 int cpu = smp_processor_id();
187
188 spin_lock_irqsave(&sparc_backtrace_lock, flags);
189
190 rw = (struct reg_window *)fp;
191 while(rw && (((unsigned long) rw) >= PAGE_OFFSET) &&
192 !(((unsigned long) rw) & 0x7)) {
193 printk("CPU[%d]: ARGS[%08lx,%08lx,%08lx,%08lx,%08lx,%08lx] "
194 "FP[%08lx] CALLER[%08lx]: ", cpu,
195 rw->ins[0], rw->ins[1], rw->ins[2], rw->ins[3],
196 rw->ins[4], rw->ins[5],
197 rw->ins[6],
198 rw->ins[7]);
199 print_symbol("%s\n", rw->ins[7]);
200 rw = (struct reg_window *) rw->ins[6];
201 }
202 spin_unlock_irqrestore(&sparc_backtrace_lock, flags);
203 }
204
205 #define __SAVE __asm__ __volatile__("save %sp, -0x40, %sp\n\t")
206 #define __RESTORE __asm__ __volatile__("restore %g0, %g0, %g0\n\t")
207 #define __GET_FP(fp) __asm__ __volatile__("mov %%i6, %0" : "=r" (fp))
208
209 void show_backtrace(void)
210 {
211 unsigned long fp;
212
213 __SAVE; __SAVE; __SAVE; __SAVE;
214 __SAVE; __SAVE; __SAVE; __SAVE;
215 __RESTORE; __RESTORE; __RESTORE; __RESTORE;
216 __RESTORE; __RESTORE; __RESTORE; __RESTORE;
217
218 __GET_FP(fp);
219
220 __show_backtrace(fp);
221 }
222
223 #ifdef CONFIG_SMP
224 void smp_show_backtrace_all_cpus(void)
225 {
226 xc0((smpfunc_t) show_backtrace);
227 show_backtrace();
228 }
229 #endif
230
231 #if 0
232 void show_stackframe(struct sparc_stackf *sf)
233 {
234 unsigned long size;
235 unsigned long *stk;
236 int i;
237
238 printk("l0: %08lx l1: %08lx l2: %08lx l3: %08lx "
239 "l4: %08lx l5: %08lx l6: %08lx l7: %08lx\n",
240 sf->locals[0], sf->locals[1], sf->locals[2], sf->locals[3],
241 sf->locals[4], sf->locals[5], sf->locals[6], sf->locals[7]);
242 printk("i0: %08lx i1: %08lx i2: %08lx i3: %08lx "
243 "i4: %08lx i5: %08lx fp: %08lx i7: %08lx\n",
244 sf->ins[0], sf->ins[1], sf->ins[2], sf->ins[3],
245 sf->ins[4], sf->ins[5], (unsigned long)sf->fp, sf->callers_pc);
246 printk("sp: %08lx x0: %08lx x1: %08lx x2: %08lx "
247 "x3: %08lx x4: %08lx x5: %08lx xx: %08lx\n",
248 (unsigned long)sf->structptr, sf->xargs[0], sf->xargs[1],
249 sf->xargs[2], sf->xargs[3], sf->xargs[4], sf->xargs[5],
250 sf->xxargs[0]);
251 size = ((unsigned long)sf->fp) - ((unsigned long)sf);
252 size -= STACKFRAME_SZ;
253 stk = (unsigned long *)((unsigned long)sf + STACKFRAME_SZ);
254 i = 0;
255 do {
256 printk("s%d: %08lx\n", i++, *stk++);
257 } while ((size -= sizeof(unsigned long)));
258 }
259 #endif
260
261 void show_regs(struct pt_regs *r)
262 {
263 struct reg_window *rw = (struct reg_window *) r->u_regs[14];
264
265 printk("PSR: %08lx PC: %08lx NPC: %08lx Y: %08lx %s\n",
266 r->psr, r->pc, r->npc, r->y, print_tainted());
267 print_symbol("PC: <%s>\n", r->pc);
268 printk("%%G: %08lx %08lx %08lx %08lx %08lx %08lx %08lx %08lx\n",
269 r->u_regs[0], r->u_regs[1], r->u_regs[2], r->u_regs[3],
270 r->u_regs[4], r->u_regs[5], r->u_regs[6], r->u_regs[7]);
271 printk("%%O: %08lx %08lx %08lx %08lx %08lx %08lx %08lx %08lx\n",
272 r->u_regs[8], r->u_regs[9], r->u_regs[10], r->u_regs[11],
273 r->u_regs[12], r->u_regs[13], r->u_regs[14], r->u_regs[15]);
274 print_symbol("RPC: <%s>\n", r->u_regs[15]);
275
276 printk("%%L: %08lx %08lx %08lx %08lx %08lx %08lx %08lx %08lx\n",
277 rw->locals[0], rw->locals[1], rw->locals[2], rw->locals[3],
278 rw->locals[4], rw->locals[5], rw->locals[6], rw->locals[7]);
279 printk("%%I: %08lx %08lx %08lx %08lx %08lx %08lx %08lx %08lx\n",
280 rw->ins[0], rw->ins[1], rw->ins[2], rw->ins[3],
281 rw->ins[4], rw->ins[5], rw->ins[6], rw->ins[7]);
282 }
283
284 /*
285 * The show_stack is an external API which we do not use ourselves.
286 * The oops is printed in die_if_kernel.
287 */
288 void show_stack(struct task_struct *tsk, unsigned long *_ksp)
289 {
290 unsigned long pc, fp;
291 unsigned long task_base;
292 struct reg_window *rw;
293 int count = 0;
294
295 if (tsk != NULL)
296 task_base = (unsigned long) task_stack_page(tsk);
297 else
298 task_base = (unsigned long) current_thread_info();
299
300 fp = (unsigned long) _ksp;
301 do {
302 /* Bogus frame pointer? */
303 if (fp < (task_base + sizeof(struct thread_info)) ||
304 fp >= (task_base + (PAGE_SIZE << 1)))
305 break;
306 rw = (struct reg_window *) fp;
307 pc = rw->ins[7];
308 printk("[%08lx : ", pc);
309 print_symbol("%s ] ", pc);
310 fp = rw->ins[6];
311 } while (++count < 16);
312 printk("\n");
313 }
314
315 void dump_stack(void)
316 {
317 unsigned long *ksp;
318
319 __asm__ __volatile__("mov %%fp, %0"
320 : "=r" (ksp));
321 show_stack(current, ksp);
322 }
323
324 EXPORT_SYMBOL(dump_stack);
325
326 /*
327 * Note: sparc64 has a pretty intricated thread_saved_pc, check it out.
328 */
329 unsigned long thread_saved_pc(struct task_struct *tsk)
330 {
331 return task_thread_info(tsk)->kpc;
332 }
333
334 /*
335 * Free current thread data structures etc..
336 */
337 void exit_thread(void)
338 {
339 #ifndef CONFIG_SMP
340 if(last_task_used_math == current) {
341 #else
342 if (test_thread_flag(TIF_USEDFPU)) {
343 #endif
344 /* Keep process from leaving FPU in a bogon state. */
345 put_psr(get_psr() | PSR_EF);
346 fpsave(&current->thread.float_regs[0], &current->thread.fsr,
347 &current->thread.fpqueue[0], &current->thread.fpqdepth);
348 #ifndef CONFIG_SMP
349 last_task_used_math = NULL;
350 #else
351 clear_thread_flag(TIF_USEDFPU);
352 #endif
353 }
354 }
355
356 void flush_thread(void)
357 {
358 current_thread_info()->w_saved = 0;
359
360 /* No new signal delivery by default */
361 current->thread.new_signal = 0;
362 #ifndef CONFIG_SMP
363 if(last_task_used_math == current) {
364 #else
365 if (test_thread_flag(TIF_USEDFPU)) {
366 #endif
367 /* Clean the fpu. */
368 put_psr(get_psr() | PSR_EF);
369 fpsave(&current->thread.float_regs[0], &current->thread.fsr,
370 &current->thread.fpqueue[0], &current->thread.fpqdepth);
371 #ifndef CONFIG_SMP
372 last_task_used_math = NULL;
373 #else
374 clear_thread_flag(TIF_USEDFPU);
375 #endif
376 }
377
378 /* Now, this task is no longer a kernel thread. */
379 current->thread.current_ds = USER_DS;
380 if (current->thread.flags & SPARC_FLAG_KTHREAD) {
381 current->thread.flags &= ~SPARC_FLAG_KTHREAD;
382
383 /* We must fixup kregs as well. */
384 /* XXX This was not fixed for ti for a while, worked. Unused? */
385 current->thread.kregs = (struct pt_regs *)
386 (task_stack_page(current) + (THREAD_SIZE - TRACEREG_SZ));
387 }
388 }
389
390 static inline struct sparc_stackf __user *
391 clone_stackframe(struct sparc_stackf __user *dst,
392 struct sparc_stackf __user *src)
393 {
394 unsigned long size, fp;
395 struct sparc_stackf *tmp;
396 struct sparc_stackf __user *sp;
397
398 if (get_user(tmp, &src->fp))
399 return NULL;
400
401 fp = (unsigned long) tmp;
402 size = (fp - ((unsigned long) src));
403 fp = (unsigned long) dst;
404 sp = (struct sparc_stackf __user *)(fp - size);
405
406 /* do_fork() grabs the parent semaphore, we must release it
407 * temporarily so we can build the child clone stack frame
408 * without deadlocking.
409 */
410 if (__copy_user(sp, src, size))
411 sp = NULL;
412 else if (put_user(fp, &sp->fp))
413 sp = NULL;
414
415 return sp;
416 }
417
418 asmlinkage int sparc_do_fork(unsigned long clone_flags,
419 unsigned long stack_start,
420 struct pt_regs *regs,
421 unsigned long stack_size)
422 {
423 unsigned long parent_tid_ptr, child_tid_ptr;
424
425 parent_tid_ptr = regs->u_regs[UREG_I2];
426 child_tid_ptr = regs->u_regs[UREG_I4];
427
428 return do_fork(clone_flags, stack_start,
429 regs, stack_size,
430 (int __user *) parent_tid_ptr,
431 (int __user *) child_tid_ptr);
432 }
433
434 /* Copy a Sparc thread. The fork() return value conventions
435 * under SunOS are nothing short of bletcherous:
436 * Parent --> %o0 == childs pid, %o1 == 0
437 * Child --> %o0 == parents pid, %o1 == 1
438 *
439 * NOTE: We have a separate fork kpsr/kwim because
440 * the parent could change these values between
441 * sys_fork invocation and when we reach here
442 * if the parent should sleep while trying to
443 * allocate the task_struct and kernel stack in
444 * do_fork().
445 * XXX See comment above sys_vfork in sparc64. todo.
446 */
447 extern void ret_from_fork(void);
448
449 int copy_thread(int nr, unsigned long clone_flags, unsigned long sp,
450 unsigned long unused,
451 struct task_struct *p, struct pt_regs *regs)
452 {
453 struct thread_info *ti = task_thread_info(p);
454 struct pt_regs *childregs;
455 char *new_stack;
456
457 #ifndef CONFIG_SMP
458 if(last_task_used_math == current) {
459 #else
460 if (test_thread_flag(TIF_USEDFPU)) {
461 #endif
462 put_psr(get_psr() | PSR_EF);
463 fpsave(&p->thread.float_regs[0], &p->thread.fsr,
464 &p->thread.fpqueue[0], &p->thread.fpqdepth);
465 #ifdef CONFIG_SMP
466 clear_thread_flag(TIF_USEDFPU);
467 #endif
468 }
469
470 /*
471 * p->thread_info new_stack childregs
472 * ! ! ! {if(PSR_PS) }
473 * V V (stk.fr.) V (pt_regs) { (stk.fr.) }
474 * +----- - - - - - ------+===========+============={+==========}+
475 */
476 new_stack = task_stack_page(p) + THREAD_SIZE;
477 if (regs->psr & PSR_PS)
478 new_stack -= STACKFRAME_SZ;
479 new_stack -= STACKFRAME_SZ + TRACEREG_SZ;
480 memcpy(new_stack, (char *)regs - STACKFRAME_SZ, STACKFRAME_SZ + TRACEREG_SZ);
481 childregs = (struct pt_regs *) (new_stack + STACKFRAME_SZ);
482
483 /*
484 * A new process must start with interrupts closed in 2.5,
485 * because this is how Mingo's scheduler works (see schedule_tail
486 * and finish_arch_switch). If we do not do it, a timer interrupt hits
487 * before we unlock, attempts to re-take the rq->lock, and then we die.
488 * Thus, kpsr|=PSR_PIL.
489 */
490 ti->ksp = (unsigned long) new_stack;
491 ti->kpc = (((unsigned long) ret_from_fork) - 0x8);
492 ti->kpsr = current->thread.fork_kpsr | PSR_PIL;
493 ti->kwim = current->thread.fork_kwim;
494
495 if(regs->psr & PSR_PS) {
496 extern struct pt_regs fake_swapper_regs;
497
498 p->thread.kregs = &fake_swapper_regs;
499 new_stack += STACKFRAME_SZ + TRACEREG_SZ;
500 childregs->u_regs[UREG_FP] = (unsigned long) new_stack;
501 p->thread.flags |= SPARC_FLAG_KTHREAD;
502 p->thread.current_ds = KERNEL_DS;
503 memcpy(new_stack, (void *)regs->u_regs[UREG_FP], STACKFRAME_SZ);
504 childregs->u_regs[UREG_G6] = (unsigned long) ti;
505 } else {
506 p->thread.kregs = childregs;
507 childregs->u_regs[UREG_FP] = sp;
508 p->thread.flags &= ~SPARC_FLAG_KTHREAD;
509 p->thread.current_ds = USER_DS;
510
511 if (sp != regs->u_regs[UREG_FP]) {
512 struct sparc_stackf __user *childstack;
513 struct sparc_stackf __user *parentstack;
514
515 /*
516 * This is a clone() call with supplied user stack.
517 * Set some valid stack frames to give to the child.
518 */
519 childstack = (struct sparc_stackf __user *)
520 (sp & ~0x7UL);
521 parentstack = (struct sparc_stackf __user *)
522 regs->u_regs[UREG_FP];
523
524 #if 0
525 printk("clone: parent stack:\n");
526 show_stackframe(parentstack);
527 #endif
528
529 childstack = clone_stackframe(childstack, parentstack);
530 if (!childstack)
531 return -EFAULT;
532
533 #if 0
534 printk("clone: child stack:\n");
535 show_stackframe(childstack);
536 #endif
537
538 childregs->u_regs[UREG_FP] = (unsigned long)childstack;
539 }
540 }
541
542 #ifdef CONFIG_SMP
543 /* FPU must be disabled on SMP. */
544 childregs->psr &= ~PSR_EF;
545 #endif
546
547 /* Set the return value for the child. */
548 childregs->u_regs[UREG_I0] = current->pid;
549 childregs->u_regs[UREG_I1] = 1;
550
551 /* Set the return value for the parent. */
552 regs->u_regs[UREG_I1] = 0;
553
554 if (clone_flags & CLONE_SETTLS)
555 childregs->u_regs[UREG_G7] = regs->u_regs[UREG_I3];
556
557 return 0;
558 }
559
560 /*
561 * fill in the fpu structure for a core dump.
562 */
563 int dump_fpu (struct pt_regs * regs, elf_fpregset_t * fpregs)
564 {
565 if (used_math()) {
566 memset(fpregs, 0, sizeof(*fpregs));
567 fpregs->pr_q_entrysize = 8;
568 return 1;
569 }
570 #ifdef CONFIG_SMP
571 if (test_thread_flag(TIF_USEDFPU)) {
572 put_psr(get_psr() | PSR_EF);
573 fpsave(&current->thread.float_regs[0], &current->thread.fsr,
574 &current->thread.fpqueue[0], &current->thread.fpqdepth);
575 if (regs != NULL) {
576 regs->psr &= ~(PSR_EF);
577 clear_thread_flag(TIF_USEDFPU);
578 }
579 }
580 #else
581 if (current == last_task_used_math) {
582 put_psr(get_psr() | PSR_EF);
583 fpsave(&current->thread.float_regs[0], &current->thread.fsr,
584 &current->thread.fpqueue[0], &current->thread.fpqdepth);
585 if (regs != NULL) {
586 regs->psr &= ~(PSR_EF);
587 last_task_used_math = NULL;
588 }
589 }
590 #endif
591 memcpy(&fpregs->pr_fr.pr_regs[0],
592 &current->thread.float_regs[0],
593 (sizeof(unsigned long) * 32));
594 fpregs->pr_fsr = current->thread.fsr;
595 fpregs->pr_qcnt = current->thread.fpqdepth;
596 fpregs->pr_q_entrysize = 8;
597 fpregs->pr_en = 1;
598 if(fpregs->pr_qcnt != 0) {
599 memcpy(&fpregs->pr_q[0],
600 &current->thread.fpqueue[0],
601 sizeof(struct fpq) * fpregs->pr_qcnt);
602 }
603 /* Zero out the rest. */
604 memset(&fpregs->pr_q[fpregs->pr_qcnt], 0,
605 sizeof(struct fpq) * (32 - fpregs->pr_qcnt));
606 return 1;
607 }
608
609 /*
610 * sparc_execve() executes a new program after the asm stub has set
611 * things up for us. This should basically do what I want it to.
612 */
613 asmlinkage int sparc_execve(struct pt_regs *regs)
614 {
615 int error, base = 0;
616 char *filename;
617
618 /* Check for indirect call. */
619 if(regs->u_regs[UREG_G1] == 0)
620 base = 1;
621
622 filename = getname((char __user *)regs->u_regs[base + UREG_I0]);
623 error = PTR_ERR(filename);
624 if(IS_ERR(filename))
625 goto out;
626 error = do_execve(filename,
627 (char __user * __user *)regs->u_regs[base + UREG_I1],
628 (char __user * __user *)regs->u_regs[base + UREG_I2],
629 regs);
630 putname(filename);
631 if (error == 0) {
632 task_lock(current);
633 current->ptrace &= ~PT_DTRACE;
634 task_unlock(current);
635 }
636 out:
637 return error;
638 }
639
640 /*
641 * This is the mechanism for creating a new kernel thread.
642 *
643 * NOTE! Only a kernel-only process(ie the swapper or direct descendants
644 * who haven't done an "execve()") should use this: it will work within
645 * a system call from a "real" process, but the process memory space will
646 * not be freed until both the parent and the child have exited.
647 */
648 pid_t kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
649 {
650 long retval;
651
652 __asm__ __volatile__("mov %4, %%g2\n\t" /* Set aside fn ptr... */
653 "mov %5, %%g3\n\t" /* and arg. */
654 "mov %1, %%g1\n\t"
655 "mov %2, %%o0\n\t" /* Clone flags. */
656 "mov 0, %%o1\n\t" /* usp arg == 0 */
657 "t 0x10\n\t" /* Linux/Sparc clone(). */
658 "cmp %%o1, 0\n\t"
659 "be 1f\n\t" /* The parent, just return. */
660 " nop\n\t" /* Delay slot. */
661 "jmpl %%g2, %%o7\n\t" /* Call the function. */
662 " mov %%g3, %%o0\n\t" /* Get back the arg in delay. */
663 "mov %3, %%g1\n\t"
664 "t 0x10\n\t" /* Linux/Sparc exit(). */
665 /* Notreached by child. */
666 "1: mov %%o0, %0\n\t" :
667 "=r" (retval) :
668 "i" (__NR_clone), "r" (flags | CLONE_VM | CLONE_UNTRACED),
669 "i" (__NR_exit), "r" (fn), "r" (arg) :
670 "g1", "g2", "g3", "o0", "o1", "memory", "cc");
671 return retval;
672 }
673
674 unsigned long get_wchan(struct task_struct *task)
675 {
676 unsigned long pc, fp, bias = 0;
677 unsigned long task_base = (unsigned long) task;
678 unsigned long ret = 0;
679 struct reg_window *rw;
680 int count = 0;
681
682 if (!task || task == current ||
683 task->state == TASK_RUNNING)
684 goto out;
685
686 fp = task_thread_info(task)->ksp + bias;
687 do {
688 /* Bogus frame pointer? */
689 if (fp < (task_base + sizeof(struct thread_info)) ||
690 fp >= (task_base + (2 * PAGE_SIZE)))
691 break;
692 rw = (struct reg_window *) fp;
693 pc = rw->ins[7];
694 if (!in_sched_functions(pc)) {
695 ret = pc;
696 goto out;
697 }
698 fp = rw->ins[6] + bias;
699 } while (++count < 16);
700
701 out:
702 return ret;
703 }
704
linux-next