1 // SPDX-License-Identifier: GPL-2.0-only
3 * thread-stack.c: Synthesize a thread's stack using call / return events
4 * Copyright (c) 2014, Intel Corporation.
7 #include <linux/rbtree.h>
8 #include <linux/list.h>
9 #include <linux/log2.h>
10 #include <linux/zalloc.h>
21 #include "call-path.h"
22 #include "thread-stack.h"
24 #define STACK_GROWTH 2048
27 * State of retpoline detection.
29 * RETPOLINE_NONE: no retpoline detection
30 * X86_RETPOLINE_POSSIBLE: x86 retpoline possible
31 * X86_RETPOLINE_DETECTED: x86 retpoline detected
33 enum retpoline_state_t {
35 X86_RETPOLINE_POSSIBLE,
36 X86_RETPOLINE_DETECTED,
40 * struct thread_stack_entry - thread stack entry.
41 * @ret_addr: return address
42 * @timestamp: timestamp (if known)
43 * @ref: external reference (e.g. db_id of sample)
44 * @branch_count: the branch count when the entry was created
45 * @insn_count: the instruction count when the entry was created
46 * @cyc_count the cycle count when the entry was created
47 * @db_id: id used for db-export
49 * @no_call: a 'call' was not seen
50 * @trace_end: a 'call' but trace ended
51 * @non_call: a branch but not a 'call' to the start of a different symbol
53 struct thread_stack_entry {
68 * struct thread_stack - thread stack constructed from 'call' and 'return'
70 * @stack: array that holds the stack
71 * @cnt: number of entries in the stack
72 * @sz: current maximum stack size
73 * @trace_nr: current trace number
74 * @branch_count: running branch count
75 * @insn_count: running instruction count
76 * @cyc_count running cycle count
77 * @kernel_start: kernel start address
78 * @last_time: last timestamp
79 * @crp: call/return processor
81 * @arr_sz: size of array if this is the first element of an array
82 * @rstate: used to detect retpolines
83 * @br_stack_rb: branch stack (ring buffer)
84 * @br_stack_sz: maximum branch stack size
85 * @br_stack_pos: current position in @br_stack_rb
86 * @mispred_all: mark all branches as mispredicted
89 struct thread_stack_entry *stack;
98 struct call_return_processor *crp;
101 enum retpoline_state_t rstate;
102 struct branch_stack *br_stack_rb;
103 unsigned int br_stack_sz;
104 unsigned int br_stack_pos;
109 * Assume pid == tid == 0 identifies the idle task as defined by
110 * perf_session__register_idle_thread(). The idle task is really 1 task per cpu,
111 * and therefore requires a stack for each cpu.
113 static inline bool thread_stack__per_cpu(struct thread *thread)
115 return !(thread->tid || thread->pid_);
118 static int thread_stack__grow(struct thread_stack *ts)
120 struct thread_stack_entry *new_stack;
123 new_sz = ts->sz + STACK_GROWTH;
124 sz = new_sz * sizeof(struct thread_stack_entry);
126 new_stack = realloc(ts->stack, sz);
130 ts->stack = new_stack;
136 static int thread_stack__init(struct thread_stack *ts, struct thread *thread,
137 struct call_return_processor *crp,
138 bool callstack, unsigned int br_stack_sz)
143 err = thread_stack__grow(ts);
149 size_t sz = sizeof(struct branch_stack);
151 sz += br_stack_sz * sizeof(struct branch_entry);
152 ts->br_stack_rb = zalloc(sz);
153 if (!ts->br_stack_rb)
155 ts->br_stack_sz = br_stack_sz;
158 if (thread->maps && thread->maps->machine) {
159 struct machine *machine = thread->maps->machine;
160 const char *arch = perf_env__arch(machine->env);
162 ts->kernel_start = machine__kernel_start(machine);
163 if (!strcmp(arch, "x86"))
164 ts->rstate = X86_RETPOLINE_POSSIBLE;
166 ts->kernel_start = 1ULL << 63;
173 static struct thread_stack *thread_stack__new(struct thread *thread, int cpu,
174 struct call_return_processor *crp,
176 unsigned int br_stack_sz)
178 struct thread_stack *ts = thread->ts, *new_ts;
179 unsigned int old_sz = ts ? ts->arr_sz : 0;
180 unsigned int new_sz = 1;
182 if (thread_stack__per_cpu(thread) && cpu > 0)
183 new_sz = roundup_pow_of_two(cpu + 1);
185 if (!ts || new_sz > old_sz) {
186 new_ts = calloc(new_sz, sizeof(*ts));
190 memcpy(new_ts, ts, old_sz * sizeof(*ts));
191 new_ts->arr_sz = new_sz;
197 if (thread_stack__per_cpu(thread) && cpu > 0 &&
198 (unsigned int)cpu < ts->arr_sz)
202 thread_stack__init(ts, thread, crp, callstack, br_stack_sz))
208 static struct thread_stack *thread__cpu_stack(struct thread *thread, int cpu)
210 struct thread_stack *ts = thread->ts;
215 if (!ts || (unsigned int)cpu >= ts->arr_sz)
226 static inline struct thread_stack *thread__stack(struct thread *thread,
232 if (thread_stack__per_cpu(thread))
233 return thread__cpu_stack(thread, cpu);
238 static int thread_stack__push(struct thread_stack *ts, u64 ret_addr,
243 if (ts->cnt == ts->sz) {
244 err = thread_stack__grow(ts);
246 pr_warning("Out of memory: discarding thread stack\n");
251 ts->stack[ts->cnt].trace_end = trace_end;
252 ts->stack[ts->cnt++].ret_addr = ret_addr;
257 static void thread_stack__pop(struct thread_stack *ts, u64 ret_addr)
262 * In some cases there may be functions which are not seen to return.
263 * For example when setjmp / longjmp has been used. Or the perf context
264 * switch in the kernel which doesn't stop and start tracing in exactly
265 * the same code path. When that happens the return address will be
266 * further down the stack. If the return address is not found at all,
267 * we assume the opposite (i.e. this is a return for a call that wasn't
268 * seen for some reason) and leave the stack alone.
270 for (i = ts->cnt; i; ) {
271 if (ts->stack[--i].ret_addr == ret_addr) {
278 static void thread_stack__pop_trace_end(struct thread_stack *ts)
282 for (i = ts->cnt; i; ) {
283 if (ts->stack[--i].trace_end)
290 static bool thread_stack__in_kernel(struct thread_stack *ts)
295 return ts->stack[ts->cnt - 1].cp->in_kernel;
298 static int thread_stack__call_return(struct thread *thread,
299 struct thread_stack *ts, size_t idx,
300 u64 timestamp, u64 ref, bool no_return)
302 struct call_return_processor *crp = ts->crp;
303 struct thread_stack_entry *tse;
304 struct call_return cr = {
311 tse = &ts->stack[idx];
313 cr.call_time = tse->timestamp;
314 cr.return_time = timestamp;
315 cr.branch_count = ts->branch_count - tse->branch_count;
316 cr.insn_count = ts->insn_count - tse->insn_count;
317 cr.cyc_count = ts->cyc_count - tse->cyc_count;
318 cr.db_id = tse->db_id;
319 cr.call_ref = tse->ref;
322 cr.flags |= CALL_RETURN_NO_CALL;
324 cr.flags |= CALL_RETURN_NO_RETURN;
326 cr.flags |= CALL_RETURN_NON_CALL;
329 * The parent db_id must be assigned before exporting the child. Note
330 * it is not possible to export the parent first because its information
331 * is not yet complete because its 'return' has not yet been processed.
333 parent_db_id = idx ? &(tse - 1)->db_id : NULL;
335 return crp->process(&cr, parent_db_id, crp->data);
338 static int __thread_stack__flush(struct thread *thread, struct thread_stack *ts)
340 struct call_return_processor *crp = ts->crp;
345 ts->br_stack_pos = 0;
347 ts->br_stack_rb->nr = 0;
352 err = thread_stack__call_return(thread, ts, --ts->cnt,
353 ts->last_time, 0, true);
355 pr_err("Error flushing thread stack!\n");
364 int thread_stack__flush(struct thread *thread)
366 struct thread_stack *ts = thread->ts;
371 for (pos = 0; pos < ts->arr_sz; pos++) {
372 int ret = __thread_stack__flush(thread, ts + pos);
382 static void thread_stack__update_br_stack(struct thread_stack *ts, u32 flags,
383 u64 from_ip, u64 to_ip)
385 struct branch_stack *bs = ts->br_stack_rb;
386 struct branch_entry *be;
388 if (!ts->br_stack_pos)
389 ts->br_stack_pos = ts->br_stack_sz;
391 ts->br_stack_pos -= 1;
393 be = &bs->entries[ts->br_stack_pos];
397 be->flags.abort = !!(flags & PERF_IP_FLAG_TX_ABORT);
398 be->flags.in_tx = !!(flags & PERF_IP_FLAG_IN_TX);
399 /* No support for mispredict */
400 be->flags.mispred = ts->mispred_all;
402 if (bs->nr < ts->br_stack_sz)
406 int thread_stack__event(struct thread *thread, int cpu, u32 flags, u64 from_ip,
407 u64 to_ip, u16 insn_len, u64 trace_nr, bool callstack,
408 unsigned int br_stack_sz, bool mispred_all)
410 struct thread_stack *ts = thread__stack(thread, cpu);
416 ts = thread_stack__new(thread, cpu, NULL, callstack, br_stack_sz);
418 pr_warning("Out of memory: no thread stack\n");
421 ts->trace_nr = trace_nr;
422 ts->mispred_all = mispred_all;
426 * When the trace is discontinuous, the trace_nr changes. In that case
427 * the stack might be completely invalid. Better to report nothing than
428 * to report something misleading, so flush the stack.
430 if (trace_nr != ts->trace_nr) {
432 __thread_stack__flush(thread, ts);
433 ts->trace_nr = trace_nr;
437 thread_stack__update_br_stack(ts, flags, from_ip, to_ip);
440 * Stop here if thread_stack__process() is in use, or not recording call
443 if (ts->crp || !callstack)
446 if (flags & PERF_IP_FLAG_CALL) {
451 ret_addr = from_ip + insn_len;
452 if (ret_addr == to_ip)
453 return 0; /* Zero-length calls are excluded */
454 return thread_stack__push(ts, ret_addr,
455 flags & PERF_IP_FLAG_TRACE_END);
456 } else if (flags & PERF_IP_FLAG_TRACE_BEGIN) {
458 * If the caller did not change the trace number (which would
459 * have flushed the stack) then try to make sense of the stack.
460 * Possibly, tracing began after returning to the current
461 * address, so try to pop that. Also, do not expect a call made
462 * when the trace ended, to return, so pop that.
464 thread_stack__pop(ts, to_ip);
465 thread_stack__pop_trace_end(ts);
466 } else if ((flags & PERF_IP_FLAG_RETURN) && from_ip) {
467 thread_stack__pop(ts, to_ip);
473 void thread_stack__set_trace_nr(struct thread *thread, int cpu, u64 trace_nr)
475 struct thread_stack *ts = thread__stack(thread, cpu);
480 if (trace_nr != ts->trace_nr) {
482 __thread_stack__flush(thread, ts);
483 ts->trace_nr = trace_nr;
487 static void __thread_stack__free(struct thread *thread, struct thread_stack *ts)
489 __thread_stack__flush(thread, ts);
491 zfree(&ts->br_stack_rb);
494 static void thread_stack__reset(struct thread *thread, struct thread_stack *ts)
496 unsigned int arr_sz = ts->arr_sz;
498 __thread_stack__free(thread, ts);
499 memset(ts, 0, sizeof(*ts));
503 void thread_stack__free(struct thread *thread)
505 struct thread_stack *ts = thread->ts;
509 for (pos = 0; pos < ts->arr_sz; pos++)
510 __thread_stack__free(thread, ts + pos);
515 static inline u64 callchain_context(u64 ip, u64 kernel_start)
517 return ip < kernel_start ? PERF_CONTEXT_USER : PERF_CONTEXT_KERNEL;
520 void thread_stack__sample(struct thread *thread, int cpu,
521 struct ip_callchain *chain,
522 size_t sz, u64 ip, u64 kernel_start)
524 struct thread_stack *ts = thread__stack(thread, cpu);
525 u64 context = callchain_context(ip, kernel_start);
534 chain->ips[0] = context;
542 last_context = context;
544 for (i = 2, j = 1; i < sz && j <= ts->cnt; i++, j++) {
545 ip = ts->stack[ts->cnt - j].ret_addr;
546 context = callchain_context(ip, kernel_start);
547 if (context != last_context) {
550 chain->ips[i++] = context;
551 last_context = context;
560 * Hardware sample records, created some time after the event occurred, need to
561 * have subsequent addresses removed from the call chain.
563 void thread_stack__sample_late(struct thread *thread, int cpu,
564 struct ip_callchain *chain, size_t sz,
565 u64 sample_ip, u64 kernel_start)
567 struct thread_stack *ts = thread__stack(thread, cpu);
568 u64 sample_context = callchain_context(sample_ip, kernel_start);
569 u64 last_context, context, ip;
581 * When tracing kernel space, kernel addresses occur at the top of the
582 * call chain after the event occurred but before tracing stopped.
585 for (j = 1; j <= ts->cnt; j++) {
586 ip = ts->stack[ts->cnt - j].ret_addr;
587 context = callchain_context(ip, kernel_start);
588 if (context == PERF_CONTEXT_USER ||
589 (context == sample_context && ip == sample_ip))
593 last_context = sample_ip; /* Use sample_ip as an invalid context */
595 for (; nr < sz && j <= ts->cnt; nr++, j++) {
596 ip = ts->stack[ts->cnt - j].ret_addr;
597 context = callchain_context(ip, kernel_start);
598 if (context != last_context) {
601 chain->ips[nr++] = context;
602 last_context = context;
610 chain->ips[0] = sample_context;
611 chain->ips[1] = sample_ip;
616 void thread_stack__br_sample(struct thread *thread, int cpu,
617 struct branch_stack *dst, unsigned int sz)
619 struct thread_stack *ts = thread__stack(thread, cpu);
620 const size_t bsz = sizeof(struct branch_entry);
621 struct branch_stack *src;
622 struct branch_entry *be;
630 src = ts->br_stack_rb;
634 dst->nr = min((unsigned int)src->nr, sz);
636 be = &dst->entries[0];
637 nr = min(ts->br_stack_sz - ts->br_stack_pos, (unsigned int)dst->nr);
638 memcpy(be, &src->entries[ts->br_stack_pos], bsz * nr);
640 if (src->nr >= ts->br_stack_sz) {
642 be = &dst->entries[nr];
643 nr = min(ts->br_stack_pos, sz);
644 memcpy(be, &src->entries[0], bsz * ts->br_stack_pos);
648 /* Start of user space branch entries */
649 static bool us_start(struct branch_entry *be, u64 kernel_start, bool *start)
652 *start = be->to && be->to < kernel_start;
658 * Start of branch entries after the ip fell in between 2 branches, or user
659 * space branch entries.
661 static bool ks_start(struct branch_entry *be, u64 sample_ip, u64 kernel_start,
662 bool *start, struct branch_entry *nb)
665 *start = (nb && sample_ip >= be->to && sample_ip <= nb->from) ||
666 be->from < kernel_start ||
667 (be->to && be->to < kernel_start);
674 * Hardware sample records, created some time after the event occurred, need to
675 * have subsequent addresses removed from the branch stack.
677 void thread_stack__br_sample_late(struct thread *thread, int cpu,
678 struct branch_stack *dst, unsigned int sz,
679 u64 ip, u64 kernel_start)
681 struct thread_stack *ts = thread__stack(thread, cpu);
682 struct branch_entry *d, *s, *spos, *ssz;
683 struct branch_stack *src;
692 src = ts->br_stack_rb;
696 spos = &src->entries[ts->br_stack_pos];
697 ssz = &src->entries[ts->br_stack_sz];
699 d = &dst->entries[0];
702 if (ip < kernel_start) {
704 * User space sample: start copying branch entries when the
705 * branch is in user space.
707 for (s = spos; s < ssz && nr < sz; s++) {
708 if (us_start(s, kernel_start, &start)) {
714 if (src->nr >= ts->br_stack_sz) {
715 for (s = &src->entries[0]; s < spos && nr < sz; s++) {
716 if (us_start(s, kernel_start, &start)) {
723 struct branch_entry *nb = NULL;
726 * Kernel space sample: start copying branch entries when the ip
727 * falls in between 2 branches (or the branch is in user space
728 * because then the start must have been missed).
730 for (s = spos; s < ssz && nr < sz; s++) {
731 if (ks_start(s, ip, kernel_start, &start, nb)) {
738 if (src->nr >= ts->br_stack_sz) {
739 for (s = &src->entries[0]; s < spos && nr < sz; s++) {
740 if (ks_start(s, ip, kernel_start, &start, nb)) {
752 struct call_return_processor *
753 call_return_processor__new(int (*process)(struct call_return *cr, u64 *parent_db_id, void *data),
756 struct call_return_processor *crp;
758 crp = zalloc(sizeof(struct call_return_processor));
761 crp->cpr = call_path_root__new();
764 crp->process = process;
773 void call_return_processor__free(struct call_return_processor *crp)
776 call_path_root__free(crp->cpr);
781 static int thread_stack__push_cp(struct thread_stack *ts, u64 ret_addr,
782 u64 timestamp, u64 ref, struct call_path *cp,
783 bool no_call, bool trace_end)
785 struct thread_stack_entry *tse;
791 if (ts->cnt == ts->sz) {
792 err = thread_stack__grow(ts);
797 tse = &ts->stack[ts->cnt++];
798 tse->ret_addr = ret_addr;
799 tse->timestamp = timestamp;
801 tse->branch_count = ts->branch_count;
802 tse->insn_count = ts->insn_count;
803 tse->cyc_count = ts->cyc_count;
805 tse->no_call = no_call;
806 tse->trace_end = trace_end;
807 tse->non_call = false;
813 static int thread_stack__pop_cp(struct thread *thread, struct thread_stack *ts,
814 u64 ret_addr, u64 timestamp, u64 ref,
823 struct thread_stack_entry *tse = &ts->stack[0];
825 if (tse->cp->sym == sym)
826 return thread_stack__call_return(thread, ts, --ts->cnt,
827 timestamp, ref, false);
830 if (ts->stack[ts->cnt - 1].ret_addr == ret_addr &&
831 !ts->stack[ts->cnt - 1].non_call) {
832 return thread_stack__call_return(thread, ts, --ts->cnt,
833 timestamp, ref, false);
835 size_t i = ts->cnt - 1;
838 if (ts->stack[i].ret_addr != ret_addr ||
839 ts->stack[i].non_call)
842 while (ts->cnt > i) {
843 err = thread_stack__call_return(thread, ts,
850 return thread_stack__call_return(thread, ts, --ts->cnt,
851 timestamp, ref, false);
858 static int thread_stack__bottom(struct thread_stack *ts,
859 struct perf_sample *sample,
860 struct addr_location *from_al,
861 struct addr_location *to_al, u64 ref)
863 struct call_path_root *cpr = ts->crp->cpr;
864 struct call_path *cp;
871 } else if (sample->addr) {
878 cp = call_path__findnew(cpr, &cpr->call_path, sym, ip,
881 return thread_stack__push_cp(ts, ip, sample->time, ref, cp,
885 static int thread_stack__pop_ks(struct thread *thread, struct thread_stack *ts,
886 struct perf_sample *sample, u64 ref)
888 u64 tm = sample->time;
891 /* Return to userspace, so pop all kernel addresses */
892 while (thread_stack__in_kernel(ts)) {
893 err = thread_stack__call_return(thread, ts, --ts->cnt,
902 static int thread_stack__no_call_return(struct thread *thread,
903 struct thread_stack *ts,
904 struct perf_sample *sample,
905 struct addr_location *from_al,
906 struct addr_location *to_al, u64 ref)
908 struct call_path_root *cpr = ts->crp->cpr;
909 struct call_path *root = &cpr->call_path;
910 struct symbol *fsym = from_al->sym;
911 struct symbol *tsym = to_al->sym;
912 struct call_path *cp, *parent;
913 u64 ks = ts->kernel_start;
914 u64 addr = sample->addr;
915 u64 tm = sample->time;
919 if (ip >= ks && addr < ks) {
920 /* Return to userspace, so pop all kernel addresses */
921 err = thread_stack__pop_ks(thread, ts, sample, ref);
925 /* If the stack is empty, push the userspace address */
927 cp = call_path__findnew(cpr, root, tsym, addr, ks);
928 return thread_stack__push_cp(ts, 0, tm, ref, cp, true,
931 } else if (thread_stack__in_kernel(ts) && ip < ks) {
932 /* Return to userspace, so pop all kernel addresses */
933 err = thread_stack__pop_ks(thread, ts, sample, ref);
939 parent = ts->stack[ts->cnt - 1].cp;
943 if (parent->sym == from_al->sym) {
945 * At the bottom of the stack, assume the missing 'call' was
946 * before the trace started. So, pop the current symbol and push
950 err = thread_stack__call_return(thread, ts, --ts->cnt,
957 cp = call_path__findnew(cpr, root, tsym, addr, ks);
959 return thread_stack__push_cp(ts, addr, tm, ref, cp,
964 * Otherwise assume the 'return' is being used as a jump (e.g.
965 * retpoline) and just push the 'to' symbol.
967 cp = call_path__findnew(cpr, parent, tsym, addr, ks);
969 err = thread_stack__push_cp(ts, 0, tm, ref, cp, true, false);
971 ts->stack[ts->cnt - 1].non_call = true;
977 * Assume 'parent' has not yet returned, so push 'to', and then push and
981 cp = call_path__findnew(cpr, parent, tsym, addr, ks);
983 err = thread_stack__push_cp(ts, addr, tm, ref, cp, true, false);
987 cp = call_path__findnew(cpr, cp, fsym, ip, ks);
989 err = thread_stack__push_cp(ts, ip, tm, ref, cp, true, false);
993 return thread_stack__call_return(thread, ts, --ts->cnt, tm, ref, false);
996 static int thread_stack__trace_begin(struct thread *thread,
997 struct thread_stack *ts, u64 timestamp,
1000 struct thread_stack_entry *tse;
1007 tse = &ts->stack[ts->cnt - 1];
1008 if (tse->trace_end) {
1009 err = thread_stack__call_return(thread, ts, --ts->cnt,
1010 timestamp, ref, false);
1018 static int thread_stack__trace_end(struct thread_stack *ts,
1019 struct perf_sample *sample, u64 ref)
1021 struct call_path_root *cpr = ts->crp->cpr;
1022 struct call_path *cp;
1025 /* No point having 'trace end' on the bottom of the stack */
1026 if (!ts->cnt || (ts->cnt == 1 && ts->stack[0].ref == ref))
1029 cp = call_path__findnew(cpr, ts->stack[ts->cnt - 1].cp, NULL, 0,
1032 ret_addr = sample->ip + sample->insn_len;
1034 return thread_stack__push_cp(ts, ret_addr, sample->time, ref, cp,
1038 static bool is_x86_retpoline(const char *name)
1040 const char *p = strstr(name, "__x86_indirect_thunk_");
1042 return p == name || !strcmp(name, "__indirect_thunk_start");
1046 * x86 retpoline functions pollute the call graph. This function removes them.
1047 * This does not handle function return thunks, nor is there any improvement
1048 * for the handling of inline thunks or extern thunks.
1050 static int thread_stack__x86_retpoline(struct thread_stack *ts,
1051 struct perf_sample *sample,
1052 struct addr_location *to_al)
1054 struct thread_stack_entry *tse = &ts->stack[ts->cnt - 1];
1055 struct call_path_root *cpr = ts->crp->cpr;
1056 struct symbol *sym = tse->cp->sym;
1057 struct symbol *tsym = to_al->sym;
1058 struct call_path *cp;
1060 if (sym && is_x86_retpoline(sym->name)) {
1062 * This is a x86 retpoline fn. It pollutes the call graph by
1063 * showing up everywhere there is an indirect branch, but does
1064 * not itself mean anything. Here the top-of-stack is removed,
1065 * by decrementing the stack count, and then further down, the
1066 * resulting top-of-stack is replaced with the actual target.
1067 * The result is that the retpoline functions will no longer
1068 * appear in the call graph. Note this only affects the call
1069 * graph, since all the original branches are left unchanged.
1072 sym = ts->stack[ts->cnt - 2].cp->sym;
1073 if (sym && sym == tsym && to_al->addr != tsym->start) {
1075 * Target is back to the middle of the symbol we came
1076 * from so assume it is an indirect jmp and forget it
1082 } else if (sym && sym == tsym) {
1084 * Target is back to the symbol we came from so assume it is an
1085 * indirect jmp and forget it altogether.
1091 cp = call_path__findnew(cpr, ts->stack[ts->cnt - 2].cp, tsym,
1092 sample->addr, ts->kernel_start);
1096 /* Replace the top-of-stack with the actual target */
1097 ts->stack[ts->cnt - 1].cp = cp;
1102 int thread_stack__process(struct thread *thread, struct comm *comm,
1103 struct perf_sample *sample,
1104 struct addr_location *from_al,
1105 struct addr_location *to_al, u64 ref,
1106 struct call_return_processor *crp)
1108 struct thread_stack *ts = thread__stack(thread, sample->cpu);
1109 enum retpoline_state_t rstate;
1112 if (ts && !ts->crp) {
1113 /* Supersede thread_stack__event() */
1114 thread_stack__reset(thread, ts);
1119 ts = thread_stack__new(thread, sample->cpu, crp, true, 0);
1125 rstate = ts->rstate;
1126 if (rstate == X86_RETPOLINE_DETECTED)
1127 ts->rstate = X86_RETPOLINE_POSSIBLE;
1129 /* Flush stack on exec */
1130 if (ts->comm != comm && thread->pid_ == thread->tid) {
1131 err = __thread_stack__flush(thread, ts);
1137 /* If the stack is empty, put the current symbol on the stack */
1139 err = thread_stack__bottom(ts, sample, from_al, to_al, ref);
1144 ts->branch_count += 1;
1145 ts->insn_count += sample->insn_cnt;
1146 ts->cyc_count += sample->cyc_cnt;
1147 ts->last_time = sample->time;
1149 if (sample->flags & PERF_IP_FLAG_CALL) {
1150 bool trace_end = sample->flags & PERF_IP_FLAG_TRACE_END;
1151 struct call_path_root *cpr = ts->crp->cpr;
1152 struct call_path *cp;
1155 if (!sample->ip || !sample->addr)
1158 ret_addr = sample->ip + sample->insn_len;
1159 if (ret_addr == sample->addr)
1160 return 0; /* Zero-length calls are excluded */
1162 cp = call_path__findnew(cpr, ts->stack[ts->cnt - 1].cp,
1163 to_al->sym, sample->addr,
1165 err = thread_stack__push_cp(ts, ret_addr, sample->time, ref,
1166 cp, false, trace_end);
1169 * A call to the same symbol but not the start of the symbol,
1170 * may be the start of a x86 retpoline.
1172 if (!err && rstate == X86_RETPOLINE_POSSIBLE && to_al->sym &&
1173 from_al->sym == to_al->sym &&
1174 to_al->addr != to_al->sym->start)
1175 ts->rstate = X86_RETPOLINE_DETECTED;
1177 } else if (sample->flags & PERF_IP_FLAG_RETURN) {
1178 if (!sample->addr) {
1179 u32 return_from_kernel = PERF_IP_FLAG_SYSCALLRET |
1180 PERF_IP_FLAG_INTERRUPT;
1182 if (!(sample->flags & return_from_kernel))
1185 /* Pop kernel stack */
1186 return thread_stack__pop_ks(thread, ts, sample, ref);
1192 /* x86 retpoline 'return' doesn't match the stack */
1193 if (rstate == X86_RETPOLINE_DETECTED && ts->cnt > 2 &&
1194 ts->stack[ts->cnt - 1].ret_addr != sample->addr)
1195 return thread_stack__x86_retpoline(ts, sample, to_al);
1197 err = thread_stack__pop_cp(thread, ts, sample->addr,
1198 sample->time, ref, from_al->sym);
1202 err = thread_stack__no_call_return(thread, ts, sample,
1203 from_al, to_al, ref);
1205 } else if (sample->flags & PERF_IP_FLAG_TRACE_BEGIN) {
1206 err = thread_stack__trace_begin(thread, ts, sample->time, ref);
1207 } else if (sample->flags & PERF_IP_FLAG_TRACE_END) {
1208 err = thread_stack__trace_end(ts, sample, ref);
1209 } else if (sample->flags & PERF_IP_FLAG_BRANCH &&
1210 from_al->sym != to_al->sym && to_al->sym &&
1211 to_al->addr == to_al->sym->start) {
1212 struct call_path_root *cpr = ts->crp->cpr;
1213 struct call_path *cp;
1216 * The compiler might optimize a call/ret combination by making
1217 * it a jmp. Make that visible by recording on the stack a
1218 * branch to the start of a different symbol. Note, that means
1219 * when a ret pops the stack, all jmps must be popped off first.
1221 cp = call_path__findnew(cpr, ts->stack[ts->cnt - 1].cp,
1222 to_al->sym, sample->addr,
1224 err = thread_stack__push_cp(ts, 0, sample->time, ref, cp, false,
1227 ts->stack[ts->cnt - 1].non_call = true;
1233 size_t thread_stack__depth(struct thread *thread, int cpu)
1235 struct thread_stack *ts = thread__stack(thread, cpu);