xref: /freebsd/sys/dev/hwpmc/hwpmc_powerpc.c (revision 97759ccc715c4b365432c16d763c50eecfcb1100)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2011,2013 Justin Hibbits
5  * Copyright (c) 2005, Joseph Koshy
6  * All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  *
29  */
30 
31 #include <sys/cdefs.h>
32 #include <sys/param.h>
33 #include <sys/pmc.h>
34 #include <sys/pmckern.h>
35 #include <sys/sysent.h>
36 #include <sys/syslog.h>
37 #include <sys/systm.h>
38 
39 #include <machine/pmc_mdep.h>
40 #include <machine/spr.h>
41 #include <machine/pte.h>
42 #include <machine/sr.h>
43 #include <machine/cpu.h>
44 #include <machine/stack.h>
45 
46 #include "hwpmc_powerpc.h"
47 
48 #ifdef __powerpc64__
49 #define OFFSET 4 /* Account for the TOC reload slot */
50 #else
51 #define OFFSET 0
52 #endif
53 
54 struct powerpc_cpu **powerpc_pcpu;
55 struct pmc_ppc_event *ppc_event_codes;
56 size_t ppc_event_codes_size;
57 int ppc_event_first;
58 int ppc_event_last;
59 int ppc_max_pmcs;
60 enum pmc_class ppc_class;
61 
62 void (*powerpc_set_pmc)(int cpu, int ri, int config);
63 pmc_value_t (*powerpc_pmcn_read)(unsigned int pmc);
64 void (*powerpc_pmcn_write)(unsigned int pmc, uint32_t val);
65 void (*powerpc_resume_pmc)(bool ie);
66 
67 
68 int
69 pmc_save_kernel_callchain(uintptr_t *cc, int maxsamples,
70     struct trapframe *tf)
71 {
72 	uintptr_t *osp, *sp;
73 	uintptr_t pc;
74 	int frames = 0;
75 
76 	cc[frames++] = PMC_TRAPFRAME_TO_PC(tf);
77 	sp = (uintptr_t *)PMC_TRAPFRAME_TO_FP(tf);
78 	osp = (uintptr_t *)PAGE_SIZE;
79 
80 	for (; frames < maxsamples; frames++) {
81 		if (sp <= osp)
82 			break;
83 	    #ifdef __powerpc64__
84 		pc = sp[2];
85 	    #else
86 		pc = sp[1];
87 	    #endif
88 		if ((pc & 3) || (pc < 0x100))
89 			break;
90 
91 		/*
92 		 * trapexit() and asttrapexit() are sentinels
93 		 * for kernel stack tracing.
94 		 * */
95 		if (pc + OFFSET == (uintptr_t) &trapexit ||
96 		    pc + OFFSET == (uintptr_t) &asttrapexit)
97 			break;
98 
99 		cc[frames] = pc;
100 		osp = sp;
101 		sp = (uintptr_t *)*sp;
102 	}
103 	return (frames);
104 }
105 
106 int
107 powerpc_describe(int cpu, int ri, struct pmc_info *pi, struct pmc **ppmc)
108 {
109 	struct pmc_hw *phw;
110 
111 	KASSERT(cpu >= 0 && cpu < pmc_cpu_max(),
112 	    ("[powerpc,%d], illegal CPU %d", __LINE__, cpu));
113 
114 	phw = &powerpc_pcpu[cpu]->pc_ppcpmcs[ri];
115 
116 	snprintf(pi->pm_name, sizeof(pi->pm_name), "POWERPC-%d", ri);
117 	pi->pm_class = powerpc_pcpu[cpu]->pc_class;
118 
119 	if (phw->phw_state & PMC_PHW_FLAG_IS_ENABLED) {
120 		pi->pm_enabled = TRUE;
121 		*ppmc          = phw->phw_pmc;
122 	} else {
123 		pi->pm_enabled = FALSE;
124 		*ppmc	       = NULL;
125 	}
126 
127 	return (0);
128 }
129 
130 int
131 powerpc_get_config(int cpu, int ri, struct pmc **ppm)
132 {
133 
134 	*ppm = powerpc_pcpu[cpu]->pc_ppcpmcs[ri].phw_pmc;
135 
136 	return (0);
137 }
138 
139 int
140 powerpc_pcpu_init(struct pmc_mdep *md, int cpu)
141 {
142 	struct pmc_cpu *pc;
143 	struct powerpc_cpu *pac;
144 	struct pmc_hw  *phw;
145 	int first_ri, i;
146 
147 	KASSERT(cpu >= 0 && cpu < pmc_cpu_max(),
148 	    ("[powerpc,%d] wrong cpu number %d", __LINE__, cpu));
149 	PMCDBG1(MDP,INI,1,"powerpc-init cpu=%d", cpu);
150 
151 	powerpc_pcpu[cpu] = pac = malloc(sizeof(struct powerpc_cpu) +
152 	    ppc_max_pmcs * sizeof(struct pmc_hw), M_PMC, M_WAITOK | M_ZERO);
153 	pac->pc_class =
154 	    md->pmd_classdep[PMC_MDEP_CLASS_INDEX_POWERPC].pcd_class;
155 
156 	pc = pmc_pcpu[cpu];
157 	first_ri = md->pmd_classdep[PMC_MDEP_CLASS_INDEX_POWERPC].pcd_ri;
158 	KASSERT(pc != NULL, ("[powerpc,%d] NULL per-cpu pointer", __LINE__));
159 
160 	for (i = 0, phw = pac->pc_ppcpmcs; i < ppc_max_pmcs; i++, phw++) {
161 		phw->phw_state = PMC_PHW_FLAG_IS_ENABLED |
162 		    PMC_PHW_CPU_TO_STATE(cpu) | PMC_PHW_INDEX_TO_STATE(i);
163 		phw->phw_pmc = NULL;
164 		pc->pc_hwpmcs[i + first_ri] = phw;
165 	}
166 
167 	return (0);
168 }
169 
170 int
171 powerpc_pcpu_fini(struct pmc_mdep *md, int cpu)
172 {
173 	PMCDBG1(MDP,INI,1,"powerpc-fini cpu=%d", cpu);
174 
175 	free(powerpc_pcpu[cpu], M_PMC);
176 	powerpc_pcpu[cpu] = NULL;
177 
178 	return (0);
179 }
180 
181 int
182 powerpc_allocate_pmc(int cpu, int ri, struct pmc *pm,
183     const struct pmc_op_pmcallocate *a)
184 {
185 	enum pmc_event pe;
186 	uint32_t caps, config = 0, counter = 0;
187 	int i;
188 
189 	KASSERT(cpu >= 0 && cpu < pmc_cpu_max(),
190 	    ("[powerpc,%d] illegal CPU value %d", __LINE__, cpu));
191 	KASSERT(ri >= 0 && ri < ppc_max_pmcs,
192 	    ("[powerpc,%d] illegal row index %d", __LINE__, ri));
193 
194 	if (a->pm_class != ppc_class)
195 		return (EINVAL);
196 
197 	caps = a->pm_caps;
198 
199 	pe = a->pm_ev;
200 
201 	if (pe < ppc_event_first || pe > ppc_event_last)
202 		return (EINVAL);
203 
204 	for (i = 0; i < ppc_event_codes_size; i++) {
205 		if (ppc_event_codes[i].pe_event == pe) {
206 			config = ppc_event_codes[i].pe_code;
207 			counter =  ppc_event_codes[i].pe_flags;
208 			break;
209 		}
210 	}
211 	if (i == ppc_event_codes_size)
212 		return (EINVAL);
213 
214 	if ((counter & (1 << ri)) == 0)
215 		return (EINVAL);
216 
217 	if (caps & PMC_CAP_SYSTEM)
218 		config |= POWERPC_PMC_KERNEL_ENABLE;
219 	if (caps & PMC_CAP_USER)
220 		config |= POWERPC_PMC_USER_ENABLE;
221 	if ((caps & (PMC_CAP_USER | PMC_CAP_SYSTEM)) == 0)
222 		config |= POWERPC_PMC_ENABLE;
223 
224 	pm->pm_md.pm_powerpc.pm_powerpc_evsel = config;
225 
226 	PMCDBG3(MDP,ALL,1,"powerpc-allocate cpu=%d ri=%d -> config=0x%x",
227 	    cpu, ri, config);
228 	return (0);
229 }
230 
231 int
232 powerpc_release_pmc(int cpu, int ri, struct pmc *pmc)
233 {
234 	struct pmc_hw *phw __diagused;
235 
236 	KASSERT(cpu >= 0 && cpu < pmc_cpu_max(),
237 	    ("[powerpc,%d] illegal CPU value %d", __LINE__, cpu));
238 	KASSERT(ri >= 0 && ri < ppc_max_pmcs,
239 	    ("[powerpc,%d] illegal row-index %d", __LINE__, ri));
240 
241 	phw = &powerpc_pcpu[cpu]->pc_ppcpmcs[ri];
242 	KASSERT(phw->phw_pmc == NULL,
243 	    ("[powerpc,%d] PHW pmc %p non-NULL", __LINE__, phw->phw_pmc));
244 
245 	return (0);
246 }
247 
248 int
249 powerpc_start_pmc(int cpu, int ri, struct pmc *pm)
250 {
251 
252 	PMCDBG2(MDP,STA,1,"powerpc-start cpu=%d ri=%d", cpu, ri);
253 	powerpc_set_pmc(cpu, ri, pm->pm_md.pm_powerpc.pm_powerpc_evsel);
254 
255 	return (0);
256 }
257 
258 int
259 powerpc_stop_pmc(int cpu, int ri, struct pmc *pm __unused)
260 {
261 	PMCDBG2(MDP,STO,1, "powerpc-stop cpu=%d ri=%d", cpu, ri);
262 	powerpc_set_pmc(cpu, ri, PMCN_NONE);
263 	return (0);
264 }
265 
266 int
267 powerpc_config_pmc(int cpu, int ri, struct pmc *pm)
268 {
269 	struct pmc_hw *phw;
270 
271 	PMCDBG3(MDP,CFG,1, "powerpc-config cpu=%d ri=%d pm=%p", cpu, ri, pm);
272 
273 	KASSERT(cpu >= 0 && cpu < pmc_cpu_max(),
274 	    ("[powerpc,%d] illegal CPU value %d", __LINE__, cpu));
275 	KASSERT(ri >= 0 && ri < ppc_max_pmcs,
276 	    ("[powerpc,%d] illegal row-index %d", __LINE__, ri));
277 
278 	phw = &powerpc_pcpu[cpu]->pc_ppcpmcs[ri];
279 
280 	KASSERT(pm == NULL || phw->phw_pmc == NULL,
281 	    ("[powerpc,%d] pm=%p phw->pm=%p hwpmc not unconfigured",
282 	    __LINE__, pm, phw->phw_pmc));
283 
284 	phw->phw_pmc = pm;
285 
286 	return (0);
287 }
288 
289 pmc_value_t
290 powerpc_pmcn_read_default(unsigned int pmc)
291 {
292 	pmc_value_t val;
293 
294 	if (pmc > ppc_max_pmcs)
295 		panic("Invalid PMC number: %d\n", pmc);
296 
297 	switch (pmc) {
298 	case 0:
299 		val = mfspr(SPR_PMC1);
300 		break;
301 	case 1:
302 		val = mfspr(SPR_PMC2);
303 		break;
304 	case 2:
305 		val = mfspr(SPR_PMC3);
306 		break;
307 	case 3:
308 		val = mfspr(SPR_PMC4);
309 		break;
310 	case 4:
311 		val = mfspr(SPR_PMC5);
312 		break;
313 	case 5:
314 		val = mfspr(SPR_PMC6);
315 		break;
316 	case 6:
317 		val = mfspr(SPR_PMC7);
318 		break;
319 	case 7:
320 		val = mfspr(SPR_PMC8);
321 		break;
322 	}
323 
324 	return (val);
325 }
326 
327 void
328 powerpc_pmcn_write_default(unsigned int pmc, uint32_t val)
329 {
330 	if (pmc > ppc_max_pmcs)
331 		panic("Invalid PMC number: %d\n", pmc);
332 
333 	switch (pmc) {
334 	case 0:
335 		mtspr(SPR_PMC1, val);
336 		break;
337 	case 1:
338 		mtspr(SPR_PMC2, val);
339 		break;
340 	case 2:
341 		mtspr(SPR_PMC3, val);
342 		break;
343 	case 3:
344 		mtspr(SPR_PMC4, val);
345 		break;
346 	case 4:
347 		mtspr(SPR_PMC5, val);
348 		break;
349 	case 5:
350 		mtspr(SPR_PMC6, val);
351 		break;
352 	case 6:
353 		mtspr(SPR_PMC7, val);
354 		break;
355 	case 7:
356 		mtspr(SPR_PMC8, val);
357 		break;
358 	}
359 }
360 
361 int
362 powerpc_read_pmc(int cpu, int ri, struct pmc *pm, pmc_value_t *v)
363 {
364 	pmc_value_t p, r, tmp;
365 
366 	KASSERT(cpu >= 0 && cpu < pmc_cpu_max(),
367 	    ("[powerpc,%d] illegal CPU value %d", __LINE__, cpu));
368 	KASSERT(ri >= 0 && ri < ppc_max_pmcs,
369 	    ("[powerpc,%d] illegal row index %d", __LINE__, ri));
370 
371 	/*
372 	 * After an interrupt occurs because of a PMC overflow, the PMC value
373 	 * is not always MAX_PMC_VALUE + 1, but may be a little above it.
374 	 * This may mess up calculations and frustrate machine independent
375 	 * layer expectations, such as that no value read should be greater
376 	 * than reload count in sampling mode.
377 	 * To avoid these issues, use MAX_PMC_VALUE as an upper limit.
378 	 */
379 	p = MIN(powerpc_pmcn_read(ri), POWERPC_MAX_PMC_VALUE);
380 	r = pm->pm_sc.pm_reloadcount;
381 
382 	if (PMC_IS_SAMPLING_MODE(PMC_TO_MODE(pm))) {
383 		/*
384 		 * Special case 1: r is too big
385 		 * This usually happens when a PMC write fails, the PMC is
386 		 * stopped and then it is read.
387 		 *
388 		 * Special case 2: PMC was reseted or has a value
389 		 * that should not be possible with current r.
390 		 *
391 		 * In the above cases, just return 0 instead of an arbitrary
392 		 * value.
393 		 */
394 		if (r > POWERPC_MAX_PMC_VALUE || p + r <= POWERPC_MAX_PMC_VALUE)
395 			tmp = 0;
396 		else
397 			tmp = POWERPC_PERFCTR_VALUE_TO_RELOAD_COUNT(p);
398 	} else
399 		tmp = p + (POWERPC_MAX_PMC_VALUE + 1) * PPC_OVERFLOWCNT(pm);
400 
401 	PMCDBG5(MDP,REA,1,"ppc-read cpu=%d ri=%d -> %jx (%jx,%jx)",
402 	    cpu, ri, (uintmax_t)tmp, (uintmax_t)PPC_OVERFLOWCNT(pm),
403 	    (uintmax_t)p);
404 	*v = tmp;
405 	return (0);
406 }
407 
408 int
409 powerpc_write_pmc(int cpu, int ri, struct pmc *pm, pmc_value_t v)
410 {
411 	pmc_value_t vlo;
412 
413 	KASSERT(cpu >= 0 && cpu < pmc_cpu_max(),
414 	    ("[powerpc,%d] illegal CPU value %d", __LINE__, cpu));
415 	KASSERT(ri >= 0 && ri < ppc_max_pmcs,
416 	    ("[powerpc,%d] illegal row-index %d", __LINE__, ri));
417 
418 	if (PMC_IS_COUNTING_MODE(PMC_TO_MODE(pm))) {
419 		PPC_OVERFLOWCNT(pm) = v / (POWERPC_MAX_PMC_VALUE + 1);
420 		vlo = v % (POWERPC_MAX_PMC_VALUE + 1);
421 	} else if (v > POWERPC_MAX_PMC_VALUE) {
422 		PMCDBG3(MDP,WRI,2,
423 		    "powerpc-write cpu=%d ri=%d: PMC value is too big: %jx",
424 		    cpu, ri, (uintmax_t)v);
425 		return (EINVAL);
426 	} else
427 		vlo = POWERPC_RELOAD_COUNT_TO_PERFCTR_VALUE(v);
428 
429 	PMCDBG5(MDP,WRI,1,"powerpc-write cpu=%d ri=%d -> %jx (%jx,%jx)",
430 	    cpu, ri, (uintmax_t)v, (uintmax_t)PPC_OVERFLOWCNT(pm),
431 	    (uintmax_t)vlo);
432 
433 	powerpc_pmcn_write(ri, vlo);
434 	return (0);
435 }
436 
437 int
438 powerpc_pmc_intr(struct trapframe *tf)
439 {
440 	struct pmc *pm;
441 	struct powerpc_cpu *pc;
442 	int cpu, error, i, retval;
443 
444 	cpu = curcpu;
445 	KASSERT(cpu >= 0 && cpu < pmc_cpu_max(),
446 	    ("[powerpc,%d] out of range CPU %d", __LINE__, cpu));
447 
448 	PMCDBG3(MDP,INT,1, "cpu=%d tf=%p um=%d", cpu, (void *) tf,
449 	    TRAPF_USERMODE(tf));
450 
451 	retval = 0;
452 	pc = powerpc_pcpu[cpu];
453 
454 	/*
455 	 * Look for a running, sampling PMC which has overflowed
456 	 * and which has a valid 'struct pmc' association.
457 	 */
458 	for (i = 0; i < ppc_max_pmcs; i++) {
459 		if (!POWERPC_PMC_HAS_OVERFLOWED(i))
460 			continue;
461 		retval = 1;	/* Found an interrupting PMC. */
462 
463 		/*
464 		 * Always clear the PMC, to make it stop interrupting.
465 		 * If pm is available and in sampling mode, use reload
466 		 * count, to make PMC read after stop correct.
467 		 * Otherwise, just reset the PMC.
468 		 */
469 		if ((pm = pc->pc_ppcpmcs[i].phw_pmc) != NULL &&
470 		    PMC_IS_SAMPLING_MODE(PMC_TO_MODE(pm))) {
471 			if (pm->pm_state != PMC_STATE_RUNNING) {
472 				powerpc_write_pmc(cpu, i, pm,
473 				    pm->pm_sc.pm_reloadcount);
474 				continue;
475 			}
476 		} else {
477 			if (pm != NULL) { /* !PMC_IS_SAMPLING_MODE */
478 				PPC_OVERFLOWCNT(pm) = (PPC_OVERFLOWCNT(pm) +
479 				    1) % PPC_OVERFLOWCNT_MAX;
480 				PMCDBG3(MDP,INT,2,
481 				    "cpu=%d ri=%d: overflowcnt=%d",
482 				    cpu, i, PPC_OVERFLOWCNT(pm));
483 			}
484 
485 			powerpc_pmcn_write(i, 0);
486 			continue;
487 		}
488 
489 		error = pmc_process_interrupt(PMC_HR, pm, tf);
490 		if (error != 0) {
491 			PMCDBG3(MDP,INT,3,
492 			    "cpu=%d ri=%d: error %d processing interrupt",
493 			    cpu, i, error);
494 			powerpc_stop_pmc(cpu, i, pm);
495 		}
496 
497 		/* Reload sampling count */
498 		powerpc_write_pmc(cpu, i, pm, pm->pm_sc.pm_reloadcount);
499 	}
500 
501 	if (retval)
502 		counter_u64_add(pmc_stats.pm_intr_processed, 1);
503 	else
504 		counter_u64_add(pmc_stats.pm_intr_ignored, 1);
505 
506 	/*
507 	 * Re-enable PERF exceptions if we were able to find the interrupt
508 	 * source and handle it. Otherwise, it's better to disable PERF
509 	 * interrupts, to avoid the risk of processing the same interrupt
510 	 * forever.
511 	 */
512 	powerpc_resume_pmc(retval != 0);
513 	if (retval == 0)
514 		log(LOG_WARNING,
515 		    "pmc_intr: couldn't find interrupting PMC on cpu %d - "
516 		    "disabling PERF interrupts\n", cpu);
517 
518 	return (retval);
519 }
520 
521 struct pmc_mdep *
522 pmc_md_initialize(void)
523 {
524 	struct pmc_mdep *pmc_mdep;
525 	int error;
526 	uint16_t vers;
527 
528 	/*
529 	 * Allocate space for pointers to PMC HW descriptors and for
530 	 * the MDEP structure used by MI code.
531 	 */
532 	powerpc_pcpu = malloc(sizeof(struct powerpc_cpu *) * pmc_cpu_max(), M_PMC,
533 			   M_WAITOK|M_ZERO);
534 
535 	/* Just one class */
536 	pmc_mdep = pmc_mdep_alloc(1);
537 
538 	vers = mfpvr() >> 16;
539 
540 	switch (vers) {
541 	case MPC7447A:
542 	case MPC7448:
543 	case MPC7450:
544 	case MPC7455:
545 	case MPC7457:
546 		error = pmc_mpc7xxx_initialize(pmc_mdep);
547 		break;
548 	case IBM970:
549 	case IBM970FX:
550 	case IBM970MP:
551 		error = pmc_ppc970_initialize(pmc_mdep);
552 		break;
553 	case IBMPOWER8E:
554 	case IBMPOWER8NVL:
555 	case IBMPOWER8:
556 	case IBMPOWER9:
557 		error = pmc_power8_initialize(pmc_mdep);
558 		break;
559 	case FSL_E500v1:
560 	case FSL_E500v2:
561 	case FSL_E500mc:
562 	case FSL_E5500:
563 		error = pmc_e500_initialize(pmc_mdep);
564 		break;
565 	default:
566 		error = -1;
567 		break;
568 	}
569 
570 	if (error != 0) {
571 		pmc_mdep_free(pmc_mdep);
572 		pmc_mdep = NULL;
573 	}
574 
575 	/* Set the value for kern.hwpmc.cpuid */
576 	snprintf(pmc_cpuid, sizeof(pmc_cpuid), "%08x", mfpvr());
577 
578 	return (pmc_mdep);
579 }
580 
581 void
582 pmc_md_finalize(struct pmc_mdep *md)
583 {
584 	PMCDBG0(MDP, INI, 1, "powerpc-finalize");
585 
586 	for (int i = 0; i < pmc_cpu_max(); i++)
587 		KASSERT(powerpc_pcpu[i] == NULL,
588 		    ("[powerpc,%d] non-null pcpu cpu %d", __LINE__, i));
589 
590 	free(powerpc_pcpu, M_PMC);
591 	powerpc_pcpu = NULL;
592 }
593 
594 int
595 pmc_save_user_callchain(uintptr_t *cc, int maxsamples,
596     struct trapframe *tf)
597 {
598 	uintptr_t *osp, *sp;
599 	int frames = 0;
600 
601 	cc[frames++] = PMC_TRAPFRAME_TO_PC(tf);
602 	sp = (uintptr_t *)PMC_TRAPFRAME_TO_FP(tf);
603 	osp = NULL;
604 
605 	for (; frames < maxsamples; frames++) {
606 		if (sp <= osp)
607 			break;
608 		osp = sp;
609 #ifdef __powerpc64__
610 		/* Check if 32-bit mode. */
611 		if (!(tf->srr1 & PSL_SF)) {
612 			cc[frames] = fuword32((uint32_t *)sp + 1);
613 			sp = (uintptr_t *)(uintptr_t)fuword32(sp);
614 		} else {
615 			cc[frames] = fuword(sp + 2);
616 			sp = (uintptr_t *)fuword(sp);
617 		}
618 #else
619 		cc[frames] = fuword32((uint32_t *)sp + 1);
620 		sp = (uintptr_t *)fuword32(sp);
621 #endif
622 	}
623 
624 	return (frames);
625 }
626