linux-stable/tools/perf/util/thread-stack.c
Thomas Gleixner 2025cf9e19 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 288
Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms and conditions of the gnu general public license
  version 2 as published by the free software foundation this program
  is distributed in the hope it will be useful but without any
  warranty without even the implied warranty of merchantability or
  fitness for a particular purpose see the gnu general public license
  for more details

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 263 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190529141901.208660670@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-05 17:36:37 +02:00

950 lines
22 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* thread-stack.c: Synthesize a thread's stack using call / return events
* Copyright (c) 2014, Intel Corporation.
*/
#include <linux/rbtree.h>
#include <linux/list.h>
#include <linux/log2.h>
#include <errno.h>
#include "thread.h"
#include "event.h"
#include "machine.h"
#include "env.h"
#include "util.h"
#include "debug.h"
#include "symbol.h"
#include "comm.h"
#include "call-path.h"
#include "thread-stack.h"
#define STACK_GROWTH 2048
/*
* State of retpoline detection.
*
* RETPOLINE_NONE: no retpoline detection
* X86_RETPOLINE_POSSIBLE: x86 retpoline possible
* X86_RETPOLINE_DETECTED: x86 retpoline detected
*/
enum retpoline_state_t {
RETPOLINE_NONE,
X86_RETPOLINE_POSSIBLE,
X86_RETPOLINE_DETECTED,
};
/**
* struct thread_stack_entry - thread stack entry.
* @ret_addr: return address
* @timestamp: timestamp (if known)
* @ref: external reference (e.g. db_id of sample)
* @branch_count: the branch count when the entry was created
* @db_id: id used for db-export
* @cp: call path
* @no_call: a 'call' was not seen
* @trace_end: a 'call' but trace ended
* @non_call: a branch but not a 'call' to the start of a different symbol
*/
struct thread_stack_entry {
u64 ret_addr;
u64 timestamp;
u64 ref;
u64 branch_count;
u64 db_id;
struct call_path *cp;
bool no_call;
bool trace_end;
bool non_call;
};
/**
* struct thread_stack - thread stack constructed from 'call' and 'return'
* branch samples.
* @stack: array that holds the stack
* @cnt: number of entries in the stack
* @sz: current maximum stack size
* @trace_nr: current trace number
* @branch_count: running branch count
* @kernel_start: kernel start address
* @last_time: last timestamp
* @crp: call/return processor
* @comm: current comm
* @arr_sz: size of array if this is the first element of an array
* @rstate: used to detect retpolines
*/
struct thread_stack {
struct thread_stack_entry *stack;
size_t cnt;
size_t sz;
u64 trace_nr;
u64 branch_count;
u64 kernel_start;
u64 last_time;
struct call_return_processor *crp;
struct comm *comm;
unsigned int arr_sz;
enum retpoline_state_t rstate;
};
/*
* Assume pid == tid == 0 identifies the idle task as defined by
* perf_session__register_idle_thread(). The idle task is really 1 task per cpu,
* and therefore requires a stack for each cpu.
*/
static inline bool thread_stack__per_cpu(struct thread *thread)
{
return !(thread->tid || thread->pid_);
}
static int thread_stack__grow(struct thread_stack *ts)
{
struct thread_stack_entry *new_stack;
size_t sz, new_sz;
new_sz = ts->sz + STACK_GROWTH;
sz = new_sz * sizeof(struct thread_stack_entry);
new_stack = realloc(ts->stack, sz);
if (!new_stack)
return -ENOMEM;
ts->stack = new_stack;
ts->sz = new_sz;
return 0;
}
static int thread_stack__init(struct thread_stack *ts, struct thread *thread,
struct call_return_processor *crp)
{
int err;
err = thread_stack__grow(ts);
if (err)
return err;
if (thread->mg && thread->mg->machine) {
struct machine *machine = thread->mg->machine;
const char *arch = perf_env__arch(machine->env);
ts->kernel_start = machine__kernel_start(machine);
if (!strcmp(arch, "x86"))
ts->rstate = X86_RETPOLINE_POSSIBLE;
} else {
ts->kernel_start = 1ULL << 63;
}
ts->crp = crp;
return 0;
}
static struct thread_stack *thread_stack__new(struct thread *thread, int cpu,
struct call_return_processor *crp)
{
struct thread_stack *ts = thread->ts, *new_ts;
unsigned int old_sz = ts ? ts->arr_sz : 0;
unsigned int new_sz = 1;
if (thread_stack__per_cpu(thread) && cpu > 0)
new_sz = roundup_pow_of_two(cpu + 1);
if (!ts || new_sz > old_sz) {
new_ts = calloc(new_sz, sizeof(*ts));
if (!new_ts)
return NULL;
if (ts)
memcpy(new_ts, ts, old_sz * sizeof(*ts));
new_ts->arr_sz = new_sz;
zfree(&thread->ts);
thread->ts = new_ts;
ts = new_ts;
}
if (thread_stack__per_cpu(thread) && cpu > 0 &&
(unsigned int)cpu < ts->arr_sz)
ts += cpu;
if (!ts->stack &&
thread_stack__init(ts, thread, crp))
return NULL;
return ts;
}
static struct thread_stack *thread__cpu_stack(struct thread *thread, int cpu)
{
struct thread_stack *ts = thread->ts;
if (cpu < 0)
cpu = 0;
if (!ts || (unsigned int)cpu >= ts->arr_sz)
return NULL;
ts += cpu;
if (!ts->stack)
return NULL;
return ts;
}
static inline struct thread_stack *thread__stack(struct thread *thread,
int cpu)
{
if (!thread)
return NULL;
if (thread_stack__per_cpu(thread))
return thread__cpu_stack(thread, cpu);
return thread->ts;
}
static int thread_stack__push(struct thread_stack *ts, u64 ret_addr,
bool trace_end)
{
int err = 0;
if (ts->cnt == ts->sz) {
err = thread_stack__grow(ts);
if (err) {
pr_warning("Out of memory: discarding thread stack\n");
ts->cnt = 0;
}
}
ts->stack[ts->cnt].trace_end = trace_end;
ts->stack[ts->cnt++].ret_addr = ret_addr;
return err;
}
static void thread_stack__pop(struct thread_stack *ts, u64 ret_addr)
{
size_t i;
/*
* In some cases there may be functions which are not seen to return.
* For example when setjmp / longjmp has been used. Or the perf context
* switch in the kernel which doesn't stop and start tracing in exactly
* the same code path. When that happens the return address will be
* further down the stack. If the return address is not found at all,
* we assume the opposite (i.e. this is a return for a call that wasn't
* seen for some reason) and leave the stack alone.
*/
for (i = ts->cnt; i; ) {
if (ts->stack[--i].ret_addr == ret_addr) {
ts->cnt = i;
return;
}
}
}
static void thread_stack__pop_trace_end(struct thread_stack *ts)
{
size_t i;
for (i = ts->cnt; i; ) {
if (ts->stack[--i].trace_end)
ts->cnt = i;
else
return;
}
}
static bool thread_stack__in_kernel(struct thread_stack *ts)
{
if (!ts->cnt)
return false;
return ts->stack[ts->cnt - 1].cp->in_kernel;
}
static int thread_stack__call_return(struct thread *thread,
struct thread_stack *ts, size_t idx,
u64 timestamp, u64 ref, bool no_return)
{
struct call_return_processor *crp = ts->crp;
struct thread_stack_entry *tse;
struct call_return cr = {
.thread = thread,
.comm = ts->comm,
.db_id = 0,
};
u64 *parent_db_id;
tse = &ts->stack[idx];
cr.cp = tse->cp;
cr.call_time = tse->timestamp;
cr.return_time = timestamp;
cr.branch_count = ts->branch_count - tse->branch_count;
cr.db_id = tse->db_id;
cr.call_ref = tse->ref;
cr.return_ref = ref;
if (tse->no_call)
cr.flags |= CALL_RETURN_NO_CALL;
if (no_return)
cr.flags |= CALL_RETURN_NO_RETURN;
if (tse->non_call)
cr.flags |= CALL_RETURN_NON_CALL;
/*
* The parent db_id must be assigned before exporting the child. Note
* it is not possible to export the parent first because its information
* is not yet complete because its 'return' has not yet been processed.
*/
parent_db_id = idx ? &(tse - 1)->db_id : NULL;
return crp->process(&cr, parent_db_id, crp->data);
}
static int __thread_stack__flush(struct thread *thread, struct thread_stack *ts)
{
struct call_return_processor *crp = ts->crp;
int err;
if (!crp) {
ts->cnt = 0;
return 0;
}
while (ts->cnt) {
err = thread_stack__call_return(thread, ts, --ts->cnt,
ts->last_time, 0, true);
if (err) {
pr_err("Error flushing thread stack!\n");
ts->cnt = 0;
return err;
}
}
return 0;
}
int thread_stack__flush(struct thread *thread)
{
struct thread_stack *ts = thread->ts;
unsigned int pos;
int err = 0;
if (ts) {
for (pos = 0; pos < ts->arr_sz; pos++) {
int ret = __thread_stack__flush(thread, ts + pos);
if (ret)
err = ret;
}
}
return err;
}
int thread_stack__event(struct thread *thread, int cpu, u32 flags, u64 from_ip,
u64 to_ip, u16 insn_len, u64 trace_nr)
{
struct thread_stack *ts = thread__stack(thread, cpu);
if (!thread)
return -EINVAL;
if (!ts) {
ts = thread_stack__new(thread, cpu, NULL);
if (!ts) {
pr_warning("Out of memory: no thread stack\n");
return -ENOMEM;
}
ts->trace_nr = trace_nr;
}
/*
* When the trace is discontinuous, the trace_nr changes. In that case
* the stack might be completely invalid. Better to report nothing than
* to report something misleading, so flush the stack.
*/
if (trace_nr != ts->trace_nr) {
if (ts->trace_nr)
__thread_stack__flush(thread, ts);
ts->trace_nr = trace_nr;
}
/* Stop here if thread_stack__process() is in use */
if (ts->crp)
return 0;
if (flags & PERF_IP_FLAG_CALL) {
u64 ret_addr;
if (!to_ip)
return 0;
ret_addr = from_ip + insn_len;
if (ret_addr == to_ip)
return 0; /* Zero-length calls are excluded */
return thread_stack__push(ts, ret_addr,
flags & PERF_IP_FLAG_TRACE_END);
} else if (flags & PERF_IP_FLAG_TRACE_BEGIN) {
/*
* If the caller did not change the trace number (which would
* have flushed the stack) then try to make sense of the stack.
* Possibly, tracing began after returning to the current
* address, so try to pop that. Also, do not expect a call made
* when the trace ended, to return, so pop that.
*/
thread_stack__pop(ts, to_ip);
thread_stack__pop_trace_end(ts);
} else if ((flags & PERF_IP_FLAG_RETURN) && from_ip) {
thread_stack__pop(ts, to_ip);
}
return 0;
}
void thread_stack__set_trace_nr(struct thread *thread, int cpu, u64 trace_nr)
{
struct thread_stack *ts = thread__stack(thread, cpu);
if (!ts)
return;
if (trace_nr != ts->trace_nr) {
if (ts->trace_nr)
__thread_stack__flush(thread, ts);
ts->trace_nr = trace_nr;
}
}
static void __thread_stack__free(struct thread *thread, struct thread_stack *ts)
{
__thread_stack__flush(thread, ts);
zfree(&ts->stack);
}
static void thread_stack__reset(struct thread *thread, struct thread_stack *ts)
{
unsigned int arr_sz = ts->arr_sz;
__thread_stack__free(thread, ts);
memset(ts, 0, sizeof(*ts));
ts->arr_sz = arr_sz;
}
void thread_stack__free(struct thread *thread)
{
struct thread_stack *ts = thread->ts;
unsigned int pos;
if (ts) {
for (pos = 0; pos < ts->arr_sz; pos++)
__thread_stack__free(thread, ts + pos);
zfree(&thread->ts);
}
}
static inline u64 callchain_context(u64 ip, u64 kernel_start)
{
return ip < kernel_start ? PERF_CONTEXT_USER : PERF_CONTEXT_KERNEL;
}
void thread_stack__sample(struct thread *thread, int cpu,
struct ip_callchain *chain,
size_t sz, u64 ip, u64 kernel_start)
{
struct thread_stack *ts = thread__stack(thread, cpu);
u64 context = callchain_context(ip, kernel_start);
u64 last_context;
size_t i, j;
if (sz < 2) {
chain->nr = 0;
return;
}
chain->ips[0] = context;
chain->ips[1] = ip;
if (!ts) {
chain->nr = 2;
return;
}
last_context = context;
for (i = 2, j = 1; i < sz && j <= ts->cnt; i++, j++) {
ip = ts->stack[ts->cnt - j].ret_addr;
context = callchain_context(ip, kernel_start);
if (context != last_context) {
if (i >= sz - 1)
break;
chain->ips[i++] = context;
last_context = context;
}
chain->ips[i] = ip;
}
chain->nr = i;
}
struct call_return_processor *
call_return_processor__new(int (*process)(struct call_return *cr, u64 *parent_db_id, void *data),
void *data)
{
struct call_return_processor *crp;
crp = zalloc(sizeof(struct call_return_processor));
if (!crp)
return NULL;
crp->cpr = call_path_root__new();
if (!crp->cpr)
goto out_free;
crp->process = process;
crp->data = data;
return crp;
out_free:
free(crp);
return NULL;
}
void call_return_processor__free(struct call_return_processor *crp)
{
if (crp) {
call_path_root__free(crp->cpr);
free(crp);
}
}
static int thread_stack__push_cp(struct thread_stack *ts, u64 ret_addr,
u64 timestamp, u64 ref, struct call_path *cp,
bool no_call, bool trace_end)
{
struct thread_stack_entry *tse;
int err;
if (!cp)
return -ENOMEM;
if (ts->cnt == ts->sz) {
err = thread_stack__grow(ts);
if (err)
return err;
}
tse = &ts->stack[ts->cnt++];
tse->ret_addr = ret_addr;
tse->timestamp = timestamp;
tse->ref = ref;
tse->branch_count = ts->branch_count;
tse->cp = cp;
tse->no_call = no_call;
tse->trace_end = trace_end;
tse->non_call = false;
tse->db_id = 0;
return 0;
}
static int thread_stack__pop_cp(struct thread *thread, struct thread_stack *ts,
u64 ret_addr, u64 timestamp, u64 ref,
struct symbol *sym)
{
int err;
if (!ts->cnt)
return 1;
if (ts->cnt == 1) {
struct thread_stack_entry *tse = &ts->stack[0];
if (tse->cp->sym == sym)
return thread_stack__call_return(thread, ts, --ts->cnt,
timestamp, ref, false);
}
if (ts->stack[ts->cnt - 1].ret_addr == ret_addr &&
!ts->stack[ts->cnt - 1].non_call) {
return thread_stack__call_return(thread, ts, --ts->cnt,
timestamp, ref, false);
} else {
size_t i = ts->cnt - 1;
while (i--) {
if (ts->stack[i].ret_addr != ret_addr ||
ts->stack[i].non_call)
continue;
i += 1;
while (ts->cnt > i) {
err = thread_stack__call_return(thread, ts,
--ts->cnt,
timestamp, ref,
true);
if (err)
return err;
}
return thread_stack__call_return(thread, ts, --ts->cnt,
timestamp, ref, false);
}
}
return 1;
}
static int thread_stack__bottom(struct thread_stack *ts,
struct perf_sample *sample,
struct addr_location *from_al,
struct addr_location *to_al, u64 ref)
{
struct call_path_root *cpr = ts->crp->cpr;
struct call_path *cp;
struct symbol *sym;
u64 ip;
if (sample->ip) {
ip = sample->ip;
sym = from_al->sym;
} else if (sample->addr) {
ip = sample->addr;
sym = to_al->sym;
} else {
return 0;
}
cp = call_path__findnew(cpr, &cpr->call_path, sym, ip,
ts->kernel_start);
return thread_stack__push_cp(ts, ip, sample->time, ref, cp,
true, false);
}
static int thread_stack__no_call_return(struct thread *thread,
struct thread_stack *ts,
struct perf_sample *sample,
struct addr_location *from_al,
struct addr_location *to_al, u64 ref)
{
struct call_path_root *cpr = ts->crp->cpr;
struct call_path *root = &cpr->call_path;
struct symbol *fsym = from_al->sym;
struct symbol *tsym = to_al->sym;
struct call_path *cp, *parent;
u64 ks = ts->kernel_start;
u64 addr = sample->addr;
u64 tm = sample->time;
u64 ip = sample->ip;
int err;
if (ip >= ks && addr < ks) {
/* Return to userspace, so pop all kernel addresses */
while (thread_stack__in_kernel(ts)) {
err = thread_stack__call_return(thread, ts, --ts->cnt,
tm, ref, true);
if (err)
return err;
}
/* If the stack is empty, push the userspace address */
if (!ts->cnt) {
cp = call_path__findnew(cpr, root, tsym, addr, ks);
return thread_stack__push_cp(ts, 0, tm, ref, cp, true,
false);
}
} else if (thread_stack__in_kernel(ts) && ip < ks) {
/* Return to userspace, so pop all kernel addresses */
while (thread_stack__in_kernel(ts)) {
err = thread_stack__call_return(thread, ts, --ts->cnt,
tm, ref, true);
if (err)
return err;
}
}
if (ts->cnt)
parent = ts->stack[ts->cnt - 1].cp;
else
parent = root;
if (parent->sym == from_al->sym) {
/*
* At the bottom of the stack, assume the missing 'call' was
* before the trace started. So, pop the current symbol and push
* the 'to' symbol.
*/
if (ts->cnt == 1) {
err = thread_stack__call_return(thread, ts, --ts->cnt,
tm, ref, false);
if (err)
return err;
}
if (!ts->cnt) {
cp = call_path__findnew(cpr, root, tsym, addr, ks);
return thread_stack__push_cp(ts, addr, tm, ref, cp,
true, false);
}
/*
* Otherwise assume the 'return' is being used as a jump (e.g.
* retpoline) and just push the 'to' symbol.
*/
cp = call_path__findnew(cpr, parent, tsym, addr, ks);
err = thread_stack__push_cp(ts, 0, tm, ref, cp, true, false);
if (!err)
ts->stack[ts->cnt - 1].non_call = true;
return err;
}
/*
* Assume 'parent' has not yet returned, so push 'to', and then push and
* pop 'from'.
*/
cp = call_path__findnew(cpr, parent, tsym, addr, ks);
err = thread_stack__push_cp(ts, addr, tm, ref, cp, true, false);
if (err)
return err;
cp = call_path__findnew(cpr, cp, fsym, ip, ks);
err = thread_stack__push_cp(ts, ip, tm, ref, cp, true, false);
if (err)
return err;
return thread_stack__call_return(thread, ts, --ts->cnt, tm, ref, false);
}
static int thread_stack__trace_begin(struct thread *thread,
struct thread_stack *ts, u64 timestamp,
u64 ref)
{
struct thread_stack_entry *tse;
int err;
if (!ts->cnt)
return 0;
/* Pop trace end */
tse = &ts->stack[ts->cnt - 1];
if (tse->trace_end) {
err = thread_stack__call_return(thread, ts, --ts->cnt,
timestamp, ref, false);
if (err)
return err;
}
return 0;
}
static int thread_stack__trace_end(struct thread_stack *ts,
struct perf_sample *sample, u64 ref)
{
struct call_path_root *cpr = ts->crp->cpr;
struct call_path *cp;
u64 ret_addr;
/* No point having 'trace end' on the bottom of the stack */
if (!ts->cnt || (ts->cnt == 1 && ts->stack[0].ref == ref))
return 0;
cp = call_path__findnew(cpr, ts->stack[ts->cnt - 1].cp, NULL, 0,
ts->kernel_start);
ret_addr = sample->ip + sample->insn_len;
return thread_stack__push_cp(ts, ret_addr, sample->time, ref, cp,
false, true);
}
static bool is_x86_retpoline(const char *name)
{
const char *p = strstr(name, "__x86_indirect_thunk_");
return p == name || !strcmp(name, "__indirect_thunk_start");
}
/*
* x86 retpoline functions pollute the call graph. This function removes them.
* This does not handle function return thunks, nor is there any improvement
* for the handling of inline thunks or extern thunks.
*/
static int thread_stack__x86_retpoline(struct thread_stack *ts,
struct perf_sample *sample,
struct addr_location *to_al)
{
struct thread_stack_entry *tse = &ts->stack[ts->cnt - 1];
struct call_path_root *cpr = ts->crp->cpr;
struct symbol *sym = tse->cp->sym;
struct symbol *tsym = to_al->sym;
struct call_path *cp;
if (sym && is_x86_retpoline(sym->name)) {
/*
* This is a x86 retpoline fn. It pollutes the call graph by
* showing up everywhere there is an indirect branch, but does
* not itself mean anything. Here the top-of-stack is removed,
* by decrementing the stack count, and then further down, the
* resulting top-of-stack is replaced with the actual target.
* The result is that the retpoline functions will no longer
* appear in the call graph. Note this only affects the call
* graph, since all the original branches are left unchanged.
*/
ts->cnt -= 1;
sym = ts->stack[ts->cnt - 2].cp->sym;
if (sym && sym == tsym && to_al->addr != tsym->start) {
/*
* Target is back to the middle of the symbol we came
* from so assume it is an indirect jmp and forget it
* altogether.
*/
ts->cnt -= 1;
return 0;
}
} else if (sym && sym == tsym) {
/*
* Target is back to the symbol we came from so assume it is an
* indirect jmp and forget it altogether.
*/
ts->cnt -= 1;
return 0;
}
cp = call_path__findnew(cpr, ts->stack[ts->cnt - 2].cp, tsym,
sample->addr, ts->kernel_start);
if (!cp)
return -ENOMEM;
/* Replace the top-of-stack with the actual target */
ts->stack[ts->cnt - 1].cp = cp;
return 0;
}
int thread_stack__process(struct thread *thread, struct comm *comm,
struct perf_sample *sample,
struct addr_location *from_al,
struct addr_location *to_al, u64 ref,
struct call_return_processor *crp)
{
struct thread_stack *ts = thread__stack(thread, sample->cpu);
enum retpoline_state_t rstate;
int err = 0;
if (ts && !ts->crp) {
/* Supersede thread_stack__event() */
thread_stack__reset(thread, ts);
ts = NULL;
}
if (!ts) {
ts = thread_stack__new(thread, sample->cpu, crp);
if (!ts)
return -ENOMEM;
ts->comm = comm;
}
rstate = ts->rstate;
if (rstate == X86_RETPOLINE_DETECTED)
ts->rstate = X86_RETPOLINE_POSSIBLE;
/* Flush stack on exec */
if (ts->comm != comm && thread->pid_ == thread->tid) {
err = __thread_stack__flush(thread, ts);
if (err)
return err;
ts->comm = comm;
}
/* If the stack is empty, put the current symbol on the stack */
if (!ts->cnt) {
err = thread_stack__bottom(ts, sample, from_al, to_al, ref);
if (err)
return err;
}
ts->branch_count += 1;
ts->last_time = sample->time;
if (sample->flags & PERF_IP_FLAG_CALL) {
bool trace_end = sample->flags & PERF_IP_FLAG_TRACE_END;
struct call_path_root *cpr = ts->crp->cpr;
struct call_path *cp;
u64 ret_addr;
if (!sample->ip || !sample->addr)
return 0;
ret_addr = sample->ip + sample->insn_len;
if (ret_addr == sample->addr)
return 0; /* Zero-length calls are excluded */
cp = call_path__findnew(cpr, ts->stack[ts->cnt - 1].cp,
to_al->sym, sample->addr,
ts->kernel_start);
err = thread_stack__push_cp(ts, ret_addr, sample->time, ref,
cp, false, trace_end);
/*
* A call to the same symbol but not the start of the symbol,
* may be the start of a x86 retpoline.
*/
if (!err && rstate == X86_RETPOLINE_POSSIBLE && to_al->sym &&
from_al->sym == to_al->sym &&
to_al->addr != to_al->sym->start)
ts->rstate = X86_RETPOLINE_DETECTED;
} else if (sample->flags & PERF_IP_FLAG_RETURN) {
if (!sample->ip || !sample->addr)
return 0;
/* x86 retpoline 'return' doesn't match the stack */
if (rstate == X86_RETPOLINE_DETECTED && ts->cnt > 2 &&
ts->stack[ts->cnt - 1].ret_addr != sample->addr)
return thread_stack__x86_retpoline(ts, sample, to_al);
err = thread_stack__pop_cp(thread, ts, sample->addr,
sample->time, ref, from_al->sym);
if (err) {
if (err < 0)
return err;
err = thread_stack__no_call_return(thread, ts, sample,
from_al, to_al, ref);
}
} else if (sample->flags & PERF_IP_FLAG_TRACE_BEGIN) {
err = thread_stack__trace_begin(thread, ts, sample->time, ref);
} else if (sample->flags & PERF_IP_FLAG_TRACE_END) {
err = thread_stack__trace_end(ts, sample, ref);
} else if (sample->flags & PERF_IP_FLAG_BRANCH &&
from_al->sym != to_al->sym && to_al->sym &&
to_al->addr == to_al->sym->start) {
struct call_path_root *cpr = ts->crp->cpr;
struct call_path *cp;
/*
* The compiler might optimize a call/ret combination by making
* it a jmp. Make that visible by recording on the stack a
* branch to the start of a different symbol. Note, that means
* when a ret pops the stack, all jmps must be popped off first.
*/
cp = call_path__findnew(cpr, ts->stack[ts->cnt - 1].cp,
to_al->sym, sample->addr,
ts->kernel_start);
err = thread_stack__push_cp(ts, 0, sample->time, ref, cp, false,
false);
if (!err)
ts->stack[ts->cnt - 1].non_call = true;
}
return err;
}
size_t thread_stack__depth(struct thread *thread, int cpu)
{
struct thread_stack *ts = thread__stack(thread, cpu);
if (!ts)
return 0;
return ts->cnt;
}