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Merge branch 'linus' into x86/quirks
[deliverable/linux.git] / arch / sparc / kernel / process.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 #ifdef CONFIG_SUN_AUXIO
172 if (auxio_power_register &&
173 (strcmp(of_console_device->type, "serial") || scons_pwroff))
174 *auxio_power_register |= AUXIO_POWER_OFF;
175 #endif
176 machine_halt();
177 }
178
179 #if 0
180
181 static DEFINE_SPINLOCK(sparc_backtrace_lock);
182
183 void __show_backtrace(unsigned long fp)
184 {
185 struct reg_window *rw;
186 unsigned long flags;
187 int cpu = smp_processor_id();
188
189 spin_lock_irqsave(&sparc_backtrace_lock, flags);
190
191 rw = (struct reg_window *)fp;
192 while(rw && (((unsigned long) rw) >= PAGE_OFFSET) &&
193 !(((unsigned long) rw) & 0x7)) {
194 printk("CPU[%d]: ARGS[%08lx,%08lx,%08lx,%08lx,%08lx,%08lx] "
195 "FP[%08lx] CALLER[%08lx]: ", cpu,
196 rw->ins[0], rw->ins[1], rw->ins[2], rw->ins[3],
197 rw->ins[4], rw->ins[5],
198 rw->ins[6],
199 rw->ins[7]);
200 printk("%pS\n", (void *) rw->ins[7]);
201 rw = (struct reg_window *) rw->ins[6];
202 }
203 spin_unlock_irqrestore(&sparc_backtrace_lock, flags);
204 }
205
206 #define __SAVE __asm__ __volatile__("save %sp, -0x40, %sp\n\t")
207 #define __RESTORE __asm__ __volatile__("restore %g0, %g0, %g0\n\t")
208 #define __GET_FP(fp) __asm__ __volatile__("mov %%i6, %0" : "=r" (fp))
209
210 void show_backtrace(void)
211 {
212 unsigned long fp;
213
214 __SAVE; __SAVE; __SAVE; __SAVE;
215 __SAVE; __SAVE; __SAVE; __SAVE;
216 __RESTORE; __RESTORE; __RESTORE; __RESTORE;
217 __RESTORE; __RESTORE; __RESTORE; __RESTORE;
218
219 __GET_FP(fp);
220
221 __show_backtrace(fp);
222 }
223
224 #ifdef CONFIG_SMP
225 void smp_show_backtrace_all_cpus(void)
226 {
227 xc0((smpfunc_t) show_backtrace);
228 show_backtrace();
229 }
230 #endif
231
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 printk("PC: <%pS>\n", (void *) 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 printk("RPC: <%pS>\n", (void *) 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 printk("%pS ] ", (void *) 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 #ifndef CONFIG_SMP
361 if(last_task_used_math == current) {
362 #else
363 if (test_thread_flag(TIF_USEDFPU)) {
364 #endif
365 /* Clean the fpu. */
366 put_psr(get_psr() | PSR_EF);
367 fpsave(&current->thread.float_regs[0], &current->thread.fsr,
368 &current->thread.fpqueue[0], &current->thread.fpqdepth);
369 #ifndef CONFIG_SMP
370 last_task_used_math = NULL;
371 #else
372 clear_thread_flag(TIF_USEDFPU);
373 #endif
374 }
375
376 /* Now, this task is no longer a kernel thread. */
377 current->thread.current_ds = USER_DS;
378 if (current->thread.flags & SPARC_FLAG_KTHREAD) {
379 current->thread.flags &= ~SPARC_FLAG_KTHREAD;
380
381 /* We must fixup kregs as well. */
382 /* XXX This was not fixed for ti for a while, worked. Unused? */
383 current->thread.kregs = (struct pt_regs *)
384 (task_stack_page(current) + (THREAD_SIZE - TRACEREG_SZ));
385 }
386 }
387
388 static inline struct sparc_stackf __user *
389 clone_stackframe(struct sparc_stackf __user *dst,
390 struct sparc_stackf __user *src)
391 {
392 unsigned long size, fp;
393 struct sparc_stackf *tmp;
394 struct sparc_stackf __user *sp;
395
396 if (get_user(tmp, &src->fp))
397 return NULL;
398
399 fp = (unsigned long) tmp;
400 size = (fp - ((unsigned long) src));
401 fp = (unsigned long) dst;
402 sp = (struct sparc_stackf __user *)(fp - size);
403
404 /* do_fork() grabs the parent semaphore, we must release it
405 * temporarily so we can build the child clone stack frame
406 * without deadlocking.
407 */
408 if (__copy_user(sp, src, size))
409 sp = NULL;
410 else if (put_user(fp, &sp->fp))
411 sp = NULL;
412
413 return sp;
414 }
415
416 asmlinkage int sparc_do_fork(unsigned long clone_flags,
417 unsigned long stack_start,
418 struct pt_regs *regs,
419 unsigned long stack_size)
420 {
421 unsigned long parent_tid_ptr, child_tid_ptr;
422 unsigned long orig_i1 = regs->u_regs[UREG_I1];
423 long ret;
424
425 parent_tid_ptr = regs->u_regs[UREG_I2];
426 child_tid_ptr = regs->u_regs[UREG_I4];
427
428 ret = do_fork(clone_flags, stack_start,
429 regs, stack_size,
430 (int __user *) parent_tid_ptr,
431 (int __user *) child_tid_ptr);
432
433 /* If we get an error and potentially restart the system
434 * call, we're screwed because copy_thread() clobbered
435 * the parent's %o1. So detect that case and restore it
436 * here.
437 */
438 if ((unsigned long)ret >= -ERESTART_RESTARTBLOCK)
439 regs->u_regs[UREG_I1] = orig_i1;
440
441 return ret;
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 = task_thread_info(p);
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 (test_thread_flag(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 clear_thread_flag(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 = task_stack_page(p) + 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 fpu structure for a core dump.
572 */
573 int dump_fpu (struct pt_regs * regs, elf_fpregset_t * fpregs)
574 {
575 if (used_math()) {
576 memset(fpregs, 0, sizeof(*fpregs));
577 fpregs->pr_q_entrysize = 8;
578 return 1;
579 }
580 #ifdef CONFIG_SMP
581 if (test_thread_flag(TIF_USEDFPU)) {
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 clear_thread_flag(TIF_USEDFPU);
588 }
589 }
590 #else
591 if (current == last_task_used_math) {
592 put_psr(get_psr() | PSR_EF);
593 fpsave(&current->thread.float_regs[0], &current->thread.fsr,
594 &current->thread.fpqueue[0], &current->thread.fpqdepth);
595 if (regs != NULL) {
596 regs->psr &= ~(PSR_EF);
597 last_task_used_math = NULL;
598 }
599 }
600 #endif
601 memcpy(&fpregs->pr_fr.pr_regs[0],
602 &current->thread.float_regs[0],
603 (sizeof(unsigned long) * 32));
604 fpregs->pr_fsr = current->thread.fsr;
605 fpregs->pr_qcnt = current->thread.fpqdepth;
606 fpregs->pr_q_entrysize = 8;
607 fpregs->pr_en = 1;
608 if(fpregs->pr_qcnt != 0) {
609 memcpy(&fpregs->pr_q[0],
610 &current->thread.fpqueue[0],
611 sizeof(struct fpq) * fpregs->pr_qcnt);
612 }
613 /* Zero out the rest. */
614 memset(&fpregs->pr_q[fpregs->pr_qcnt], 0,
615 sizeof(struct fpq) * (32 - fpregs->pr_qcnt));
616 return 1;
617 }
618
619 /*
620 * sparc_execve() executes a new program after the asm stub has set
621 * things up for us. This should basically do what I want it to.
622 */
623 asmlinkage int sparc_execve(struct pt_regs *regs)
624 {
625 int error, base = 0;
626 char *filename;
627
628 /* Check for indirect call. */
629 if(regs->u_regs[UREG_G1] == 0)
630 base = 1;
631
632 filename = getname((char __user *)regs->u_regs[base + UREG_I0]);
633 error = PTR_ERR(filename);
634 if(IS_ERR(filename))
635 goto out;
636 error = do_execve(filename,
637 (char __user * __user *)regs->u_regs[base + UREG_I1],
638 (char __user * __user *)regs->u_regs[base + UREG_I2],
639 regs);
640 putname(filename);
641 out:
642 return error;
643 }
644
645 /*
646 * This is the mechanism for creating a new kernel thread.
647 *
648 * NOTE! Only a kernel-only process(ie the swapper or direct descendants
649 * who haven't done an "execve()") should use this: it will work within
650 * a system call from a "real" process, but the process memory space will
651 * not be freed until both the parent and the child have exited.
652 */
653 pid_t kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
654 {
655 long retval;
656
657 __asm__ __volatile__("mov %4, %%g2\n\t" /* Set aside fn ptr... */
658 "mov %5, %%g3\n\t" /* and arg. */
659 "mov %1, %%g1\n\t"
660 "mov %2, %%o0\n\t" /* Clone flags. */
661 "mov 0, %%o1\n\t" /* usp arg == 0 */
662 "t 0x10\n\t" /* Linux/Sparc clone(). */
663 "cmp %%o1, 0\n\t"
664 "be 1f\n\t" /* The parent, just return. */
665 " nop\n\t" /* Delay slot. */
666 "jmpl %%g2, %%o7\n\t" /* Call the function. */
667 " mov %%g3, %%o0\n\t" /* Get back the arg in delay. */
668 "mov %3, %%g1\n\t"
669 "t 0x10\n\t" /* Linux/Sparc exit(). */
670 /* Notreached by child. */
671 "1: mov %%o0, %0\n\t" :
672 "=r" (retval) :
673 "i" (__NR_clone), "r" (flags | CLONE_VM | CLONE_UNTRACED),
674 "i" (__NR_exit), "r" (fn), "r" (arg) :
675 "g1", "g2", "g3", "o0", "o1", "memory", "cc");
676 return retval;
677 }
678
679 unsigned long get_wchan(struct task_struct *task)
680 {
681 unsigned long pc, fp, bias = 0;
682 unsigned long task_base = (unsigned long) task;
683 unsigned long ret = 0;
684 struct reg_window *rw;
685 int count = 0;
686
687 if (!task || task == current ||
688 task->state == TASK_RUNNING)
689 goto out;
690
691 fp = task_thread_info(task)->ksp + bias;
692 do {
693 /* Bogus frame pointer? */
694 if (fp < (task_base + sizeof(struct thread_info)) ||
695 fp >= (task_base + (2 * PAGE_SIZE)))
696 break;
697 rw = (struct reg_window *) fp;
698 pc = rw->ins[7];
699 if (!in_sched_functions(pc)) {
700 ret = pc;
701 goto out;
702 }
703 fp = rw->ins[6] + bias;
704 } while (++count < 16);
705
706 out:
707 return ret;
708 }
709
Linux kernel - Deliverables
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