| 1 | |
| 2 | |
| 3 | * thread-stack.c: Synthesize a thread's stack using call / return events
|
| 4 | * Copyright (c) 2014, Intel Corporation.
|
| 5 |
|
| 6 |
|
| 7 | #include <linux/rbtree.h>
|
| 8 | #include <linux/list.h>
|
| 9 | #include <linux/log2.h>
|
| 10 | #include <linux/zalloc.h>
|
| 11 | #include <errno.h>
|
| 12 | #include <stdlib.h>
|
| 13 | #include <string.h>
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| 14 | #include "thread.h"
|
| 15 | #include "event.h"
|
| 16 | #include "machine.h"
|
| 17 | #include "env.h"
|
| 18 | #include "debug.h"
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| 19 | #include "symbol.h"
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| 20 | #include "comm.h"
|
| 21 | #include "call-path.h"
|
| 22 | #include "thread-stack.h"
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| 23 |
|
| 24 | #define STACK_GROWTH 2048
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| 25 |
|
| 26 | |
| 27 | * State of retpoline detection.
|
| 28 | *
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| 29 | * RETPOLINE_NONE: no retpoline detection
|
| 30 | * X86_RETPOLINE_POSSIBLE: x86 retpoline possible
|
| 31 | * X86_RETPOLINE_DETECTED: x86 retpoline detected
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| 32 |
|
| 33 | enum retpoline_state_t {
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| 34 | RETPOLINE_NONE,
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| 35 | X86_RETPOLINE_POSSIBLE,
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| 36 | X86_RETPOLINE_DETECTED,
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| 37 | };
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| 38 |
|
| 39 | |
| 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
|
| 48 | * @cp: call path
|
| 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
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| 52 |
|
| 53 | struct thread_stack_entry {
|
| 54 | u64 ret_addr;
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| 55 | u64 timestamp;
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| 56 | u64 ref;
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| 57 | u64 branch_count;
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| 58 | u64 insn_count;
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| 59 | u64 cyc_count;
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| 60 | u64 db_id;
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| 61 | struct call_path *cp;
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| 62 | bool no_call;
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| 63 | bool trace_end;
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| 64 | bool non_call;
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| 65 | };
|
| 66 |
|
| 67 | |
| 68 | * struct thread_stack - thread stack constructed from 'call' and 'return'
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| 69 | * branch samples.
|
| 70 | * @stack: array that holds the stack
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| 71 | * @cnt: number of entries in the stack
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| 72 | * @sz: current maximum stack size
|
| 73 | * @trace_nr: current trace number
|
| 74 | * @branch_count: running branch count
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| 75 | * @insn_count: running instruction count
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| 76 | * @cyc_count running cycle count
|
| 77 | * @kernel_start: kernel start address
|
| 78 | * @last_time: last timestamp
|
| 79 | * @crp: call/return processor
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| 80 | * @comm: current comm
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| 81 | * @arr_sz: size of array if this is the first element of an array
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| 82 | * @rstate: used to detect retpolines
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| 83 | * @br_stack_rb: branch stack (ring buffer)
|
| 84 | * @br_stack_sz: maximum branch stack size
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| 85 | * @br_stack_pos: current position in @br_stack_rb
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| 86 | * @mispred_all: mark all branches as mispredicted
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| 87 |
|
| 88 | struct thread_stack {
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| 89 | struct thread_stack_entry *stack;
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| 90 | size_t cnt;
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| 91 | size_t sz;
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| 92 | u64 trace_nr;
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| 93 | u64 branch_count;
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| 94 | u64 insn_count;
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| 95 | u64 cyc_count;
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| 96 | u64 kernel_start;
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| 97 | u64 last_time;
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| 98 | struct call_return_processor *crp;
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| 99 | struct comm *comm;
|
| 100 | unsigned int arr_sz;
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| 101 | enum retpoline_state_t rstate;
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| 102 | struct branch_stack *br_stack_rb;
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| 103 | unsigned int br_stack_sz;
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| 104 | unsigned int br_stack_pos;
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| 105 | bool mispred_all;
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| 106 | };
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| 107 |
|
| 108 | |
| 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.
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| 112 |
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| 113 | static inline bool thread_stack__per_cpu(struct thread *thread)
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| 114 | {
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| 115 | return !(thread__tid(thread) || thread__pid(thread));
|
| 116 | }
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| 117 |
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| 118 | static int thread_stack__grow(struct thread_stack *ts)
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| 119 | {
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| 120 | struct thread_stack_entry *new_stack;
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| 121 | size_t sz, new_sz;
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| 122 |
|
| 123 | new_sz = ts->sz + STACK_GROWTH;
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| 124 | sz = new_sz * sizeof(struct thread_stack_entry);
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| 125 |
|
| 126 | new_stack = realloc(ts->stack, sz);
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| 127 | if (!new_stack)
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| 128 | return -ENOMEM;
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| 129 |
|
| 130 | ts->stack = new_stack;
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| 131 | ts->sz = new_sz;
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| 132 |
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| 133 | return 0;
|
| 134 | }
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| 135 |
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| 136 | static int thread_stack__init(struct thread_stack *ts, struct thread *thread,
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| 137 | struct call_return_processor *crp,
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| 138 | bool callstack, unsigned int br_stack_sz)
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| 139 | {
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| 140 | int err;
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| 141 |
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| 142 | if (callstack) {
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| 143 | err = thread_stack__grow(ts);
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| 144 | if (err)
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| 145 | return err;
|
| 146 | }
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| 147 |
|
| 148 | if (br_stack_sz) {
|
| 149 | size_t sz = sizeof(struct branch_stack);
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| 150 |
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| 151 | sz += br_stack_sz * sizeof(struct branch_entry);
|
| 152 | ts->br_stack_rb = zalloc(sz);
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| 153 | if (!ts->br_stack_rb)
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| 154 | return -ENOMEM;
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| 155 | ts->br_stack_sz = br_stack_sz;
|
| 156 | }
|
| 157 |
|
| 158 | if (thread__maps(thread) && maps__machine(thread__maps(thread))) {
|
| 159 | struct machine *machine = maps__machine(thread__maps(thread));
|
| 160 | uint16_t e_machine = thread__e_machine(thread, machine, NULL);
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| 161 |
|
| 162 | ts->kernel_start = machine__kernel_start(machine);
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| 163 | if (e_machine == EM_X86_64 || e_machine == EM_386)
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| 164 | ts->rstate = X86_RETPOLINE_POSSIBLE;
|
| 165 | } else {
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| 166 | ts->kernel_start = 1ULL << 63;
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| 167 | }
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| 168 | ts->crp = crp;
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| 169 |
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| 170 | return 0;
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| 171 | }
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| 172 |
|
| 173 | static struct thread_stack *thread_stack__new(struct thread *thread, int cpu,
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| 174 | struct call_return_processor *crp,
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| 175 | bool callstack,
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| 176 | unsigned int br_stack_sz)
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| 177 | {
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| 178 | struct thread_stack *ts = thread__ts(thread), *new_ts;
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| 179 | unsigned int old_sz = ts ? ts->arr_sz : 0;
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| 180 | unsigned int new_sz = 1;
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| 181 |
|
| 182 | if (thread_stack__per_cpu(thread) && cpu > 0)
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| 183 | new_sz = roundup_pow_of_two(cpu + 1);
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| 184 |
|
| 185 | if (!ts || new_sz > old_sz) {
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| 186 | new_ts = calloc(new_sz, sizeof(*ts));
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| 187 | if (!new_ts)
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| 188 | return NULL;
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| 189 | if (ts)
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| 190 | memcpy(new_ts, ts, old_sz * sizeof(*ts));
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| 191 | new_ts->arr_sz = new_sz;
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| 192 | free(thread__ts(thread));
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| 193 | thread__set_ts(thread, new_ts);
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| 194 | ts = new_ts;
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| 195 | }
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| 196 |
|
| 197 | if (thread_stack__per_cpu(thread) && cpu > 0 &&
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| 198 | (unsigned int)cpu < ts->arr_sz)
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| 199 | ts += cpu;
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| 200 |
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| 201 | if (!ts->stack &&
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| 202 | thread_stack__init(ts, thread, crp, callstack, br_stack_sz))
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| 203 | return NULL;
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| 204 |
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| 205 | return ts;
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| 206 | }
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| 207 |
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| 208 | static struct thread_stack *thread__cpu_stack(struct thread *thread, int cpu)
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| 209 | {
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| 210 | struct thread_stack *ts = thread__ts(thread);
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| 211 |
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| 212 | if (cpu < 0)
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| 213 | cpu = 0;
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| 214 |
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| 215 | if (!ts || (unsigned int)cpu >= ts->arr_sz)
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| 216 | return NULL;
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| 217 |
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| 218 | ts += cpu;
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| 219 |
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| 220 | if (!ts->stack)
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| 221 | return NULL;
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| 222 |
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| 223 | return ts;
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| 224 | }
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| 225 |
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| 226 | static inline struct thread_stack *thread__stack(struct thread *thread,
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| 227 | int cpu)
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| 228 | {
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| 229 | if (!thread)
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| 230 | return NULL;
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| 231 |
|
| 232 | if (thread_stack__per_cpu(thread))
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| 233 | return thread__cpu_stack(thread, cpu);
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| 234 |
|
| 235 | return thread__ts(thread);
|
| 236 | }
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| 237 |
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| 238 | static int thread_stack__push(struct thread_stack *ts, u64 ret_addr,
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| 239 | bool trace_end)
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| 240 | {
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| 241 | int err = 0;
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| 242 |
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| 243 | if (ts->cnt == ts->sz) {
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| 244 | err = thread_stack__grow(ts);
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| 245 | if (err) {
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| 246 | pr_warning("Out of memory: discarding thread stack\n");
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| 247 | ts->cnt = 0;
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| 248 | }
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| 249 | }
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| 250 |
|
| 251 | ts->stack[ts->cnt].trace_end = trace_end;
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| 252 | ts->stack[ts->cnt++].ret_addr = ret_addr;
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| 253 |
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| 254 | return err;
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| 255 | }
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| 256 |
|
| 257 | static void thread_stack__pop(struct thread_stack *ts, u64 ret_addr)
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| 258 | {
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| 259 | size_t i;
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| 260 |
|
| 261 | |
| 262 | * In some cases there may be functions which are not seen to return.
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| 263 | * For example when setjmp / longjmp has been used. Or the perf context
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| 264 | * switch in the kernel which doesn't stop and start tracing in exactly
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| 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,
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| 267 | * we assume the opposite (i.e. this is a return for a call that wasn't
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| 268 | * seen for some reason) and leave the stack alone.
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| 269 |
|
| 270 | for (i = ts->cnt; i; ) {
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| 271 | if (ts->stack[--i].ret_addr == ret_addr) {
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| 272 | ts->cnt = i;
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| 273 | return;
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| 274 | }
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| 275 | }
|
| 276 | }
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| 277 |
|
| 278 | static void thread_stack__pop_trace_end(struct thread_stack *ts)
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| 279 | {
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| 280 | size_t i;
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| 281 |
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| 282 | for (i = ts->cnt; i; ) {
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| 283 | if (ts->stack[--i].trace_end)
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| 284 | ts->cnt = i;
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| 285 | else
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| 286 | return;
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| 287 | }
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| 288 | }
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| 289 |
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| 290 | static bool thread_stack__in_kernel(struct thread_stack *ts)
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| 291 | {
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| 292 | if (!ts->cnt)
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| 293 | return false;
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| 294 |
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| 295 | return ts->stack[ts->cnt - 1].cp->in_kernel;
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| 296 | }
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| 297 |
|
| 298 | static int thread_stack__call_return(struct thread *thread,
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| 299 | struct thread_stack *ts, size_t idx,
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| 300 | u64 timestamp, u64 ref, bool no_return)
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| 301 | {
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| 302 | struct call_return_processor *crp = ts->crp;
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| 303 | struct thread_stack_entry *tse;
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| 304 | struct call_return cr = {
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| 305 | .thread = thread,
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| 306 | .comm = ts->comm,
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| 307 | .db_id = 0,
|
| 308 | };
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| 309 | u64 *parent_db_id;
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| 310 |
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| 311 | tse = &ts->stack[idx];
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| 312 | cr.cp = tse->cp;
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| 313 | cr.call_time = tse->timestamp;
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| 314 | cr.return_time = timestamp;
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| 315 | cr.branch_count = ts->branch_count - tse->branch_count;
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| 316 | cr.insn_count = ts->insn_count - tse->insn_count;
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| 317 | cr.cyc_count = ts->cyc_count - tse->cyc_count;
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| 318 | cr.db_id = tse->db_id;
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| 319 | cr.call_ref = tse->ref;
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| 320 | cr.return_ref = ref;
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| 321 | if (tse->no_call)
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| 322 | cr.flags |= CALL_RETURN_NO_CALL;
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| 323 | if (no_return)
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| 324 | cr.flags |= CALL_RETURN_NO_RETURN;
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| 325 | if (tse->non_call)
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| 326 | cr.flags |= CALL_RETURN_NON_CALL;
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| 327 |
|
| 328 | |
| 329 | * The parent db_id must be assigned before exporting the child. Note
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| 330 | * it is not possible to export the parent first because its information
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| 331 | * is not yet complete because its 'return' has not yet been processed.
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| 332 |
|
| 333 | parent_db_id = idx ? &(tse - 1)->db_id : NULL;
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| 334 |
|
| 335 | return crp->process(&cr, parent_db_id, crp->data);
|
| 336 | }
|
| 337 |
|
| 338 | static int __thread_stack__flush(struct thread *thread, struct thread_stack *ts)
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| 339 | {
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| 340 | struct call_return_processor *crp = ts->crp;
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| 341 | int err;
|
| 342 |
|
| 343 | if (!crp) {
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| 344 | ts->cnt = 0;
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| 345 | ts->br_stack_pos = 0;
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| 346 | if (ts->br_stack_rb)
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| 347 | ts->br_stack_rb->nr = 0;
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| 348 | return 0;
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| 349 | }
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| 350 |
|
| 351 | while (ts->cnt) {
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| 352 | err = thread_stack__call_return(thread, ts, --ts->cnt,
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| 353 | ts->last_time, 0, true);
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| 354 | if (err) {
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| 355 | pr_err("Error flushing thread stack!\n");
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| 356 | ts->cnt = 0;
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| 357 | return err;
|
| 358 | }
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| 359 | }
|
| 360 |
|
| 361 | return 0;
|
| 362 | }
|
| 363 |
|
| 364 | int thread_stack__flush(struct thread *thread)
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| 365 | {
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| 366 | struct thread_stack *ts = thread__ts(thread);
|
| 367 | unsigned int pos;
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| 368 | int err = 0;
|
| 369 |
|
| 370 | if (ts) {
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| 371 | for (pos = 0; pos < ts->arr_sz; pos++) {
|
| 372 | int ret = __thread_stack__flush(thread, ts + pos);
|
| 373 |
|
| 374 | if (ret)
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| 375 | err = ret;
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| 376 | }
|
| 377 | }
|
| 378 |
|
| 379 | return err;
|
| 380 | }
|
| 381 |
|
| 382 | static void thread_stack__update_br_stack(struct thread_stack *ts, u32 flags,
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| 383 | u64 from_ip, u64 to_ip)
|
| 384 | {
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| 385 | struct branch_stack *bs = ts->br_stack_rb;
|
| 386 | struct branch_entry *be;
|
| 387 |
|
| 388 | if (!ts->br_stack_pos)
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| 389 | ts->br_stack_pos = ts->br_stack_sz;
|
| 390 |
|
| 391 | ts->br_stack_pos -= 1;
|
| 392 |
|
| 393 | be = &bs->entries[ts->br_stack_pos];
|
| 394 | be->from = from_ip;
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| 395 | be->to = to_ip;
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| 396 | be->flags.value = 0;
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| 397 | be->flags.abort = !!(flags & PERF_IP_FLAG_TX_ABORT);
|
| 398 | be->flags.in_tx = !!(flags & PERF_IP_FLAG_IN_TX);
|
| 399 |
|
| 400 | be->flags.mispred = ts->mispred_all;
|
| 401 |
|
| 402 | if (bs->nr < ts->br_stack_sz)
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| 403 | bs->nr += 1;
|
| 404 | }
|
| 405 |
|
| 406 | int thread_stack__event(struct thread *thread, int cpu, u32 flags, u64 from_ip,
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| 407 | u64 to_ip, u16 insn_len, u64 trace_nr, bool callstack,
|
| 408 | unsigned int br_stack_sz, bool mispred_all)
|
| 409 | {
|
| 410 | struct thread_stack *ts = thread__stack(thread, cpu);
|
| 411 |
|
| 412 | if (!thread)
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| 413 | return -EINVAL;
|
| 414 |
|
| 415 | if (!ts) {
|
| 416 | ts = thread_stack__new(thread, cpu, NULL, callstack, br_stack_sz);
|
| 417 | if (!ts) {
|
| 418 | pr_warning("Out of memory: no thread stack\n");
|
| 419 | return -ENOMEM;
|
| 420 | }
|
| 421 | ts->trace_nr = trace_nr;
|
| 422 | ts->mispred_all = mispred_all;
|
| 423 | }
|
| 424 |
|
| 425 | |
| 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.
|
| 429 |
|
| 430 | if (trace_nr != ts->trace_nr) {
|
| 431 | if (ts->trace_nr)
|
| 432 | __thread_stack__flush(thread, ts);
|
| 433 | ts->trace_nr = trace_nr;
|
| 434 | }
|
| 435 |
|
| 436 | if (br_stack_sz)
|
| 437 | thread_stack__update_br_stack(ts, flags, from_ip, to_ip);
|
| 438 |
|
| 439 | |
| 440 | * Stop here if thread_stack__process() is in use, or not recording call
|
| 441 | * stack.
|
| 442 |
|
| 443 | if (ts->crp || !callstack)
|
| 444 | return 0;
|
| 445 |
|
| 446 | if (flags & PERF_IP_FLAG_CALL) {
|
| 447 | u64 ret_addr;
|
| 448 |
|
| 449 | if (!to_ip)
|
| 450 | return 0;
|
| 451 | ret_addr = from_ip + insn_len;
|
| 452 | if (ret_addr == to_ip)
|
| 453 | return 0;
|
| 454 | return thread_stack__push(ts, ret_addr,
|
| 455 | flags & PERF_IP_FLAG_TRACE_END);
|
| 456 | } else if (flags & PERF_IP_FLAG_TRACE_BEGIN) {
|
| 457 | |
| 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.
|
| 463 |
|
| 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);
|
| 468 | }
|
| 469 |
|
| 470 | return 0;
|
| 471 | }
|
| 472 |
|
| 473 | void thread_stack__set_trace_nr(struct thread *thread, int cpu, u64 trace_nr)
|
| 474 | {
|
| 475 | struct thread_stack *ts = thread__stack(thread, cpu);
|
| 476 |
|
| 477 | if (!ts)
|
| 478 | return;
|
| 479 |
|
| 480 | if (trace_nr != ts->trace_nr) {
|
| 481 | if (ts->trace_nr)
|
| 482 | __thread_stack__flush(thread, ts);
|
| 483 | ts->trace_nr = trace_nr;
|
| 484 | }
|
| 485 | }
|
| 486 |
|
| 487 | static void __thread_stack__free(struct thread *thread, struct thread_stack *ts)
|
| 488 | {
|
| 489 | __thread_stack__flush(thread, ts);
|
| 490 | zfree(&ts->stack);
|
| 491 | zfree(&ts->br_stack_rb);
|
| 492 | }
|
| 493 |
|
| 494 | static void thread_stack__reset(struct thread *thread, struct thread_stack *ts)
|
| 495 | {
|
| 496 | unsigned int arr_sz = ts->arr_sz;
|
| 497 |
|
| 498 | __thread_stack__free(thread, ts);
|
| 499 | memset(ts, 0, sizeof(*ts));
|
| 500 | ts->arr_sz = arr_sz;
|
| 501 | }
|
| 502 |
|
| 503 | void thread_stack__free(struct thread *thread)
|
| 504 | {
|
| 505 | struct thread_stack *ts = thread__ts(thread);
|
| 506 | unsigned int pos;
|
| 507 |
|
| 508 | if (ts) {
|
| 509 | for (pos = 0; pos < ts->arr_sz; pos++)
|
| 510 | __thread_stack__free(thread, ts + pos);
|
| 511 | free(thread__ts(thread));
|
| 512 | thread__set_ts(thread, NULL);
|
| 513 | }
|
| 514 | }
|
| 515 |
|
| 516 | static inline u64 callchain_context(u64 ip, u64 kernel_start)
|
| 517 | {
|
| 518 | return ip < kernel_start ? PERF_CONTEXT_USER : PERF_CONTEXT_KERNEL;
|
| 519 | }
|
| 520 |
|
| 521 | void thread_stack__sample(struct thread *thread, int cpu,
|
| 522 | struct ip_callchain *chain,
|
| 523 | size_t sz, u64 ip, u64 kernel_start)
|
| 524 | {
|
| 525 | struct thread_stack *ts = thread__stack(thread, cpu);
|
| 526 | u64 context = callchain_context(ip, kernel_start);
|
| 527 | u64 last_context;
|
| 528 | size_t i, j;
|
| 529 |
|
| 530 | if (sz < 2) {
|
| 531 | chain->nr = 0;
|
| 532 | return;
|
| 533 | }
|
| 534 |
|
| 535 | chain->ips[0] = context;
|
| 536 | chain->ips[1] = ip;
|
| 537 |
|
| 538 | if (!ts) {
|
| 539 | chain->nr = 2;
|
| 540 | return;
|
| 541 | }
|
| 542 |
|
| 543 | last_context = context;
|
| 544 |
|
| 545 | for (i = 2, j = 1; i < sz && j <= ts->cnt; i++, j++) {
|
| 546 | ip = ts->stack[ts->cnt - j].ret_addr;
|
| 547 | context = callchain_context(ip, kernel_start);
|
| 548 | if (context != last_context) {
|
| 549 | if (i >= sz - 1)
|
| 550 | break;
|
| 551 | chain->ips[i++] = context;
|
| 552 | last_context = context;
|
| 553 | }
|
| 554 | chain->ips[i] = ip;
|
| 555 | }
|
| 556 |
|
| 557 | chain->nr = i;
|
| 558 | }
|
| 559 |
|
| 560 | |
| 561 | * Hardware sample records, created some time after the event occurred, need to
|
| 562 | * have subsequent addresses removed from the call chain.
|
| 563 |
|
| 564 | void thread_stack__sample_late(struct thread *thread, int cpu,
|
| 565 | struct ip_callchain *chain, size_t sz,
|
| 566 | u64 sample_ip, u64 kernel_start)
|
| 567 | {
|
| 568 | struct thread_stack *ts = thread__stack(thread, cpu);
|
| 569 | u64 sample_context = callchain_context(sample_ip, kernel_start);
|
| 570 | u64 last_context, context, ip;
|
| 571 | size_t nr = 0, j;
|
| 572 |
|
| 573 | if (sz < 2) {
|
| 574 | chain->nr = 0;
|
| 575 | return;
|
| 576 | }
|
| 577 |
|
| 578 | if (!ts)
|
| 579 | goto out;
|
| 580 |
|
| 581 | |
| 582 | * When tracing kernel space, kernel addresses occur at the top of the
|
| 583 | * call chain after the event occurred but before tracing stopped.
|
| 584 | * Skip them.
|
| 585 |
|
| 586 | for (j = 1; j <= ts->cnt; j++) {
|
| 587 | ip = ts->stack[ts->cnt - j].ret_addr;
|
| 588 | context = callchain_context(ip, kernel_start);
|
| 589 | if (context == PERF_CONTEXT_USER ||
|
| 590 | (context == sample_context && ip == sample_ip))
|
| 591 | break;
|
| 592 | }
|
| 593 |
|
| 594 | last_context = sample_ip;
|
| 595 |
|
| 596 | for (; nr < sz && j <= ts->cnt; nr++, j++) {
|
| 597 | ip = ts->stack[ts->cnt - j].ret_addr;
|
| 598 | context = callchain_context(ip, kernel_start);
|
| 599 | if (context != last_context) {
|
| 600 | if (nr >= sz - 1)
|
| 601 | break;
|
| 602 | chain->ips[nr++] = context;
|
| 603 | last_context = context;
|
| 604 | }
|
| 605 | chain->ips[nr] = ip;
|
| 606 | }
|
| 607 | out:
|
| 608 | if (nr) {
|
| 609 | chain->nr = nr;
|
| 610 | } else {
|
| 611 | chain->ips[0] = sample_context;
|
| 612 | chain->ips[1] = sample_ip;
|
| 613 | chain->nr = 2;
|
| 614 | }
|
| 615 | }
|
| 616 |
|
| 617 | void thread_stack__br_sample(struct thread *thread, int cpu,
|
| 618 | struct branch_stack *dst, unsigned int sz)
|
| 619 | {
|
| 620 | struct thread_stack *ts = thread__stack(thread, cpu);
|
| 621 | const size_t bsz = sizeof(struct branch_entry);
|
| 622 | struct branch_stack *src;
|
| 623 | struct branch_entry *be;
|
| 624 | unsigned int nr;
|
| 625 |
|
| 626 | dst->nr = 0;
|
| 627 |
|
| 628 | if (!ts)
|
| 629 | return;
|
| 630 |
|
| 631 | src = ts->br_stack_rb;
|
| 632 | if (!src->nr)
|
| 633 | return;
|
| 634 |
|
| 635 | dst->nr = min((unsigned int)src->nr, sz);
|
| 636 |
|
| 637 | be = &dst->entries[0];
|
| 638 | nr = min(ts->br_stack_sz - ts->br_stack_pos, (unsigned int)dst->nr);
|
| 639 | memcpy(be, &src->entries[ts->br_stack_pos], bsz * nr);
|
| 640 |
|
| 641 | if (src->nr >= ts->br_stack_sz) {
|
| 642 | sz -= nr;
|
| 643 | be = &dst->entries[nr];
|
| 644 | nr = min(ts->br_stack_pos, sz);
|
| 645 | memcpy(be, &src->entries[0], bsz * nr);
|
| 646 | }
|
| 647 | }
|
| 648 |
|
| 649 |
|
| 650 | static bool us_start(struct branch_entry *be, u64 kernel_start, bool *start)
|
| 651 | {
|
| 652 | if (!*start)
|
| 653 | *start = be->to && be->to < kernel_start;
|
| 654 |
|
| 655 | return *start;
|
| 656 | }
|
| 657 |
|
| 658 | |
| 659 | * Start of branch entries after the ip fell in between 2 branches, or user
|
| 660 | * space branch entries.
|
| 661 |
|
| 662 | static bool ks_start(struct branch_entry *be, u64 sample_ip, u64 kernel_start,
|
| 663 | bool *start, struct branch_entry *nb)
|
| 664 | {
|
| 665 | if (!*start) {
|
| 666 | *start = (nb && sample_ip >= be->to && sample_ip <= nb->from) ||
|
| 667 | be->from < kernel_start ||
|
| 668 | (be->to && be->to < kernel_start);
|
| 669 | }
|
| 670 |
|
| 671 | return *start;
|
| 672 | }
|
| 673 |
|
| 674 | |
| 675 | * Hardware sample records, created some time after the event occurred, need to
|
| 676 | * have subsequent addresses removed from the branch stack.
|
| 677 |
|
| 678 | void thread_stack__br_sample_late(struct thread *thread, int cpu,
|
| 679 | struct branch_stack *dst, unsigned int sz,
|
| 680 | u64 ip, u64 kernel_start)
|
| 681 | {
|
| 682 | struct thread_stack *ts = thread__stack(thread, cpu);
|
| 683 | struct branch_entry *d, *s, *spos, *ssz;
|
| 684 | struct branch_stack *src;
|
| 685 | unsigned int nr = 0;
|
| 686 | bool start = false;
|
| 687 |
|
| 688 | dst->nr = 0;
|
| 689 |
|
| 690 | if (!ts)
|
| 691 | return;
|
| 692 |
|
| 693 | src = ts->br_stack_rb;
|
| 694 | if (!src->nr)
|
| 695 | return;
|
| 696 |
|
| 697 | spos = &src->entries[ts->br_stack_pos];
|
| 698 | ssz = &src->entries[ts->br_stack_sz];
|
| 699 |
|
| 700 | d = &dst->entries[0];
|
| 701 | s = spos;
|
| 702 |
|
| 703 | if (ip < kernel_start) {
|
| 704 | |
| 705 | * User space sample: start copying branch entries when the
|
| 706 | * branch is in user space.
|
| 707 |
|
| 708 | for (s = spos; s < ssz && nr < sz; s++) {
|
| 709 | if (us_start(s, kernel_start, &start)) {
|
| 710 | *d++ = *s;
|
| 711 | nr += 1;
|
| 712 | }
|
| 713 | }
|
| 714 |
|
| 715 | if (src->nr >= ts->br_stack_sz) {
|
| 716 | for (s = &src->entries[0]; s < spos && nr < sz; s++) {
|
| 717 | if (us_start(s, kernel_start, &start)) {
|
| 718 | *d++ = *s;
|
| 719 | nr += 1;
|
| 720 | }
|
| 721 | }
|
| 722 | }
|
| 723 | } else {
|
| 724 | struct branch_entry *nb = NULL;
|
| 725 |
|
| 726 | |
| 727 | * Kernel space sample: start copying branch entries when the ip
|
| 728 | * falls in between 2 branches (or the branch is in user space
|
| 729 | * because then the start must have been missed).
|
| 730 |
|
| 731 | for (s = spos; s < ssz && nr < sz; s++) {
|
| 732 | if (ks_start(s, ip, kernel_start, &start, nb)) {
|
| 733 | *d++ = *s;
|
| 734 | nr += 1;
|
| 735 | }
|
| 736 | nb = s;
|
| 737 | }
|
| 738 |
|
| 739 | if (src->nr >= ts->br_stack_sz) {
|
| 740 | for (s = &src->entries[0]; s < spos && nr < sz; s++) {
|
| 741 | if (ks_start(s, ip, kernel_start, &start, nb)) {
|
| 742 | *d++ = *s;
|
| 743 | nr += 1;
|
| 744 | }
|
| 745 | nb = s;
|
| 746 | }
|
| 747 | }
|
| 748 | }
|
| 749 |
|
| 750 | dst->nr = nr;
|
| 751 | }
|
| 752 |
|
| 753 | struct call_return_processor *
|
| 754 | call_return_processor__new(int (*process)(struct call_return *cr, u64 *parent_db_id, void *data),
|
| 755 | void *data)
|
| 756 | {
|
| 757 | struct call_return_processor *crp;
|
| 758 |
|
| 759 | crp = zalloc(sizeof(struct call_return_processor));
|
| 760 | if (!crp)
|
| 761 | return NULL;
|
| 762 | crp->cpr = call_path_root__new();
|
| 763 | if (!crp->cpr)
|
| 764 | goto out_free;
|
| 765 | crp->process = process;
|
| 766 | crp->data = data;
|
| 767 | return crp;
|
| 768 |
|
| 769 | out_free:
|
| 770 | free(crp);
|
| 771 | return NULL;
|
| 772 | }
|
| 773 |
|
| 774 | void call_return_processor__free(struct call_return_processor *crp)
|
| 775 | {
|
| 776 | if (crp) {
|
| 777 | call_path_root__free(crp->cpr);
|
| 778 | free(crp);
|
| 779 | }
|
| 780 | }
|
| 781 |
|
| 782 | static int thread_stack__push_cp(struct thread_stack *ts, u64 ret_addr,
|
| 783 | u64 timestamp, u64 ref, struct call_path *cp,
|
| 784 | bool no_call, bool trace_end)
|
| 785 | {
|
| 786 | struct thread_stack_entry *tse;
|
| 787 | int err;
|
| 788 |
|
| 789 | if (!cp)
|
| 790 | return -ENOMEM;
|
| 791 |
|
| 792 | if (ts->cnt == ts->sz) {
|
| 793 | err = thread_stack__grow(ts);
|
| 794 | if (err)
|
| 795 | return err;
|
| 796 | }
|
| 797 |
|
| 798 | tse = &ts->stack[ts->cnt++];
|
| 799 | tse->ret_addr = ret_addr;
|
| 800 | tse->timestamp = timestamp;
|
| 801 | tse->ref = ref;
|
| 802 | tse->branch_count = ts->branch_count;
|
| 803 | tse->insn_count = ts->insn_count;
|
| 804 | tse->cyc_count = ts->cyc_count;
|
| 805 | tse->cp = cp;
|
| 806 | tse->no_call = no_call;
|
| 807 | tse->trace_end = trace_end;
|
| 808 | tse->non_call = false;
|
| 809 | tse->db_id = 0;
|
| 810 |
|
| 811 | return 0;
|
| 812 | }
|
| 813 |
|
| 814 | static int thread_stack__pop_cp(struct thread *thread, struct thread_stack *ts,
|
| 815 | u64 ret_addr, u64 timestamp, u64 ref,
|
| 816 | struct symbol *sym)
|
| 817 | {
|
| 818 | int err;
|
| 819 |
|
| 820 | if (!ts->cnt)
|
| 821 | return 1;
|
| 822 |
|
| 823 | if (ts->cnt == 1) {
|
| 824 | struct thread_stack_entry *tse = &ts->stack[0];
|
| 825 |
|
| 826 | if (tse->cp->sym == sym)
|
| 827 | return thread_stack__call_return(thread, ts, --ts->cnt,
|
| 828 | timestamp, ref, false);
|
| 829 | }
|
| 830 |
|
| 831 | if (ts->stack[ts->cnt - 1].ret_addr == ret_addr &&
|
| 832 | !ts->stack[ts->cnt - 1].non_call) {
|
| 833 | return thread_stack__call_return(thread, ts, --ts->cnt,
|
| 834 | timestamp, ref, false);
|
| 835 | } else {
|
| 836 | size_t i = ts->cnt - 1;
|
| 837 |
|
| 838 | while (i--) {
|
| 839 | if (ts->stack[i].ret_addr != ret_addr ||
|
| 840 | ts->stack[i].non_call)
|
| 841 | continue;
|
| 842 | i += 1;
|
| 843 | while (ts->cnt > i) {
|
| 844 | err = thread_stack__call_return(thread, ts,
|
| 845 | --ts->cnt,
|
| 846 | timestamp, ref,
|
| 847 | true);
|
| 848 | if (err)
|
| 849 | return err;
|
| 850 | }
|
| 851 | return thread_stack__call_return(thread, ts, --ts->cnt,
|
| 852 | timestamp, ref, false);
|
| 853 | }
|
| 854 | }
|
| 855 |
|
| 856 | return 1;
|
| 857 | }
|
| 858 |
|
| 859 | static int thread_stack__bottom(struct thread_stack *ts,
|
| 860 | struct perf_sample *sample,
|
| 861 | struct addr_location *from_al,
|
| 862 | struct addr_location *to_al, u64 ref)
|
| 863 | {
|
| 864 | struct call_path_root *cpr = ts->crp->cpr;
|
| 865 | struct call_path *cp;
|
| 866 | struct symbol *sym;
|
| 867 | u64 ip;
|
| 868 |
|
| 869 | if (sample->ip) {
|
| 870 | ip = sample->ip;
|
| 871 | sym = from_al->sym;
|
| 872 | } else if (sample->addr) {
|
| 873 | ip = sample->addr;
|
| 874 | sym = to_al->sym;
|
| 875 | } else {
|
| 876 | return 0;
|
| 877 | }
|
| 878 |
|
| 879 | cp = call_path__findnew(cpr, &cpr->call_path, sym, ip,
|
| 880 | ts->kernel_start);
|
| 881 |
|
| 882 | return thread_stack__push_cp(ts, ip, sample->time, ref, cp,
|
| 883 | true, false);
|
| 884 | }
|
| 885 |
|
| 886 | static int thread_stack__pop_ks(struct thread *thread, struct thread_stack *ts,
|
| 887 | struct perf_sample *sample, u64 ref)
|
| 888 | {
|
| 889 | u64 tm = sample->time;
|
| 890 | int err;
|
| 891 |
|
| 892 |
|
| 893 | while (thread_stack__in_kernel(ts)) {
|
| 894 | err = thread_stack__call_return(thread, ts, --ts->cnt,
|
| 895 | tm, ref, true);
|
| 896 | if (err)
|
| 897 | return err;
|
| 898 | }
|
| 899 |
|
| 900 | return 0;
|
| 901 | }
|
| 902 |
|
| 903 | static int thread_stack__no_call_return(struct thread *thread,
|
| 904 | struct thread_stack *ts,
|
| 905 | struct perf_sample *sample,
|
| 906 | struct addr_location *from_al,
|
| 907 | struct addr_location *to_al, u64 ref)
|
| 908 | {
|
| 909 | struct call_path_root *cpr = ts->crp->cpr;
|
| 910 | struct call_path *root = &cpr->call_path;
|
| 911 | struct symbol *fsym = from_al->sym;
|
| 912 | struct symbol *tsym = to_al->sym;
|
| 913 | struct call_path *cp, *parent;
|
| 914 | u64 ks = ts->kernel_start;
|
| 915 | u64 addr = sample->addr;
|
| 916 | u64 tm = sample->time;
|
| 917 | u64 ip = sample->ip;
|
| 918 | int err;
|
| 919 |
|
| 920 | if (ip >= ks && addr < ks) {
|
| 921 |
|
| 922 | err = thread_stack__pop_ks(thread, ts, sample, ref);
|
| 923 | if (err)
|
| 924 | return err;
|
| 925 |
|
| 926 |
|
| 927 | if (!ts->cnt) {
|
| 928 | cp = call_path__findnew(cpr, root, tsym, addr, ks);
|
| 929 | return thread_stack__push_cp(ts, 0, tm, ref, cp, true,
|
| 930 | false);
|
| 931 | }
|
| 932 | } else if (thread_stack__in_kernel(ts) && ip < ks) {
|
| 933 |
|
| 934 | err = thread_stack__pop_ks(thread, ts, sample, ref);
|
| 935 | if (err)
|
| 936 | return err;
|
| 937 | }
|
| 938 |
|
| 939 | if (ts->cnt)
|
| 940 | parent = ts->stack[ts->cnt - 1].cp;
|
| 941 | else
|
| 942 | parent = root;
|
| 943 |
|
| 944 | if (parent->sym == from_al->sym) {
|
| 945 | |
| 946 | * At the bottom of the stack, assume the missing 'call' was
|
| 947 | * before the trace started. So, pop the current symbol and push
|
| 948 | * the 'to' symbol.
|
| 949 |
|
| 950 | if (ts->cnt == 1) {
|
| 951 | err = thread_stack__call_return(thread, ts, --ts->cnt,
|
| 952 | tm, ref, false);
|
| 953 | if (err)
|
| 954 | return err;
|
| 955 | }
|
| 956 |
|
| 957 | if (!ts->cnt) {
|
| 958 | cp = call_path__findnew(cpr, root, tsym, addr, ks);
|
| 959 |
|
| 960 | return thread_stack__push_cp(ts, addr, tm, ref, cp,
|
| 961 | true, false);
|
| 962 | }
|
| 963 |
|
| 964 | |
| 965 | * Otherwise assume the 'return' is being used as a jump (e.g.
|
| 966 | * retpoline) and just push the 'to' symbol.
|
| 967 |
|
| 968 | cp = call_path__findnew(cpr, parent, tsym, addr, ks);
|
| 969 |
|
| 970 | err = thread_stack__push_cp(ts, 0, tm, ref, cp, true, false);
|
| 971 | if (!err)
|
| 972 | ts->stack[ts->cnt - 1].non_call = true;
|
| 973 |
|
| 974 | return err;
|
| 975 | }
|
| 976 |
|
| 977 | |
| 978 | * Assume 'parent' has not yet returned, so push 'to', and then push and
|
| 979 | * pop 'from'.
|
| 980 |
|
| 981 |
|
| 982 | cp = call_path__findnew(cpr, parent, tsym, addr, ks);
|
| 983 |
|
| 984 | err = thread_stack__push_cp(ts, addr, tm, ref, cp, true, false);
|
| 985 | if (err)
|
| 986 | return err;
|
| 987 |
|
| 988 | cp = call_path__findnew(cpr, cp, fsym, ip, ks);
|
| 989 |
|
| 990 | err = thread_stack__push_cp(ts, ip, tm, ref, cp, true, false);
|
| 991 | if (err)
|
| 992 | return err;
|
| 993 |
|
| 994 | return thread_stack__call_return(thread, ts, --ts->cnt, tm, ref, false);
|
| 995 | }
|
| 996 |
|
| 997 | static int thread_stack__trace_begin(struct thread *thread,
|
| 998 | struct thread_stack *ts, u64 timestamp,
|
| 999 | u64 ref)
|
| 1000 | {
|
| 1001 | struct thread_stack_entry *tse;
|
| 1002 | int err;
|
| 1003 |
|
| 1004 | if (!ts->cnt)
|
| 1005 | return 0;
|
| 1006 |
|
| 1007 |
|
| 1008 | tse = &ts->stack[ts->cnt - 1];
|
| 1009 | if (tse->trace_end) {
|
| 1010 | err = thread_stack__call_return(thread, ts, --ts->cnt,
|
| 1011 | timestamp, ref, false);
|
| 1012 | if (err)
|
| 1013 | return err;
|
| 1014 | }
|
| 1015 |
|
| 1016 | return 0;
|
| 1017 | }
|
| 1018 |
|
| 1019 | static int thread_stack__trace_end(struct thread_stack *ts,
|
| 1020 | struct perf_sample *sample, u64 ref)
|
| 1021 | {
|
| 1022 | struct call_path_root *cpr = ts->crp->cpr;
|
| 1023 | struct call_path *cp;
|
| 1024 | u64 ret_addr;
|
| 1025 |
|
| 1026 |
|
| 1027 | if (!ts->cnt || (ts->cnt == 1 && ts->stack[0].ref == ref))
|
| 1028 | return 0;
|
| 1029 |
|
| 1030 | cp = call_path__findnew(cpr, ts->stack[ts->cnt - 1].cp, NULL, 0,
|
| 1031 | ts->kernel_start);
|
| 1032 |
|
| 1033 | ret_addr = sample->ip + sample->insn_len;
|
| 1034 |
|
| 1035 | return thread_stack__push_cp(ts, ret_addr, sample->time, ref, cp,
|
| 1036 | false, true);
|
| 1037 | }
|
| 1038 |
|
| 1039 | static bool is_x86_retpoline(const char *name)
|
| 1040 | {
|
| 1041 | return strstr(name, "__x86_indirect_thunk_") == name;
|
| 1042 | }
|
| 1043 |
|
| 1044 | |
| 1045 | * x86 retpoline functions pollute the call graph. This function removes them.
|
| 1046 | * This does not handle function return thunks, nor is there any improvement
|
| 1047 | * for the handling of inline thunks or extern thunks.
|
| 1048 |
|
| 1049 | static int thread_stack__x86_retpoline(struct thread_stack *ts,
|
| 1050 | struct perf_sample *sample,
|
| 1051 | struct addr_location *to_al)
|
| 1052 | {
|
| 1053 | struct thread_stack_entry *tse = &ts->stack[ts->cnt - 1];
|
| 1054 | struct call_path_root *cpr = ts->crp->cpr;
|
| 1055 | struct symbol *sym = tse->cp->sym;
|
| 1056 | struct symbol *tsym = to_al->sym;
|
| 1057 | struct call_path *cp;
|
| 1058 |
|
| 1059 | if (sym && is_x86_retpoline(sym->name)) {
|
| 1060 | |
| 1061 | * This is a x86 retpoline fn. It pollutes the call graph by
|
| 1062 | * showing up everywhere there is an indirect branch, but does
|
| 1063 | * not itself mean anything. Here the top-of-stack is removed,
|
| 1064 | * by decrementing the stack count, and then further down, the
|
| 1065 | * resulting top-of-stack is replaced with the actual target.
|
| 1066 | * The result is that the retpoline functions will no longer
|
| 1067 | * appear in the call graph. Note this only affects the call
|
| 1068 | * graph, since all the original branches are left unchanged.
|
| 1069 |
|
| 1070 | ts->cnt -= 1;
|
| 1071 | sym = ts->stack[ts->cnt - 2].cp->sym;
|
| 1072 | if (sym && sym == tsym && to_al->addr != tsym->start) {
|
| 1073 | |
| 1074 | * Target is back to the middle of the symbol we came
|
| 1075 | * from so assume it is an indirect jmp and forget it
|
| 1076 | * altogether.
|
| 1077 |
|
| 1078 | ts->cnt -= 1;
|
| 1079 | return 0;
|
| 1080 | }
|
| 1081 | } else if (sym && sym == tsym) {
|
| 1082 | |
| 1083 | * Target is back to the symbol we came from so assume it is an
|
| 1084 | * indirect jmp and forget it altogether.
|
| 1085 |
|
| 1086 | ts->cnt -= 1;
|
| 1087 | return 0;
|
| 1088 | }
|
| 1089 |
|
| 1090 | cp = call_path__findnew(cpr, ts->stack[ts->cnt - 2].cp, tsym,
|
| 1091 | sample->addr, ts->kernel_start);
|
| 1092 | if (!cp)
|
| 1093 | return -ENOMEM;
|
| 1094 |
|
| 1095 |
|
| 1096 | ts->stack[ts->cnt - 1].cp = cp;
|
| 1097 |
|
| 1098 | return 0;
|
| 1099 | }
|
| 1100 |
|
| 1101 | int thread_stack__process(struct thread *thread, struct comm *comm,
|
| 1102 | struct perf_sample *sample,
|
| 1103 | struct addr_location *from_al,
|
| 1104 | struct addr_location *to_al, u64 ref,
|
| 1105 | struct call_return_processor *crp)
|
| 1106 | {
|
| 1107 | struct thread_stack *ts = thread__stack(thread, sample->cpu);
|
| 1108 | enum retpoline_state_t rstate;
|
| 1109 | int err = 0;
|
| 1110 |
|
| 1111 | if (ts && !ts->crp) {
|
| 1112 |
|
| 1113 | thread_stack__reset(thread, ts);
|
| 1114 | ts = NULL;
|
| 1115 | }
|
| 1116 |
|
| 1117 | if (!ts) {
|
| 1118 | ts = thread_stack__new(thread, sample->cpu, crp, true, 0);
|
| 1119 | if (!ts)
|
| 1120 | return -ENOMEM;
|
| 1121 | ts->comm = comm;
|
| 1122 | }
|
| 1123 |
|
| 1124 | rstate = ts->rstate;
|
| 1125 | if (rstate == X86_RETPOLINE_DETECTED)
|
| 1126 | ts->rstate = X86_RETPOLINE_POSSIBLE;
|
| 1127 |
|
| 1128 |
|
| 1129 | if (ts->comm != comm && thread__pid(thread) == thread__tid(thread)) {
|
| 1130 | err = __thread_stack__flush(thread, ts);
|
| 1131 | if (err)
|
| 1132 | return err;
|
| 1133 | ts->comm = comm;
|
| 1134 | }
|
| 1135 |
|
| 1136 |
|
| 1137 | if (!ts->cnt) {
|
| 1138 | err = thread_stack__bottom(ts, sample, from_al, to_al, ref);
|
| 1139 | if (err)
|
| 1140 | return err;
|
| 1141 | }
|
| 1142 |
|
| 1143 | ts->branch_count += 1;
|
| 1144 | ts->insn_count += sample->insn_cnt;
|
| 1145 | ts->cyc_count += sample->cyc_cnt;
|
| 1146 | ts->last_time = sample->time;
|
| 1147 |
|
| 1148 | if (sample->flags & PERF_IP_FLAG_CALL) {
|
| 1149 | bool trace_end = sample->flags & PERF_IP_FLAG_TRACE_END;
|
| 1150 | struct call_path_root *cpr = ts->crp->cpr;
|
| 1151 | struct call_path *cp;
|
| 1152 | u64 ret_addr;
|
| 1153 |
|
| 1154 | if (!sample->ip || !sample->addr)
|
| 1155 | return 0;
|
| 1156 |
|
| 1157 | ret_addr = sample->ip + sample->insn_len;
|
| 1158 | if (ret_addr == sample->addr)
|
| 1159 | return 0;
|
| 1160 |
|
| 1161 | cp = call_path__findnew(cpr, ts->stack[ts->cnt - 1].cp,
|
| 1162 | to_al->sym, sample->addr,
|
| 1163 | ts->kernel_start);
|
| 1164 | err = thread_stack__push_cp(ts, ret_addr, sample->time, ref,
|
| 1165 | cp, false, trace_end);
|
| 1166 |
|
| 1167 | |
| 1168 | * A call to the same symbol but not the start of the symbol,
|
| 1169 | * may be the start of a x86 retpoline.
|
| 1170 |
|
| 1171 | if (!err && rstate == X86_RETPOLINE_POSSIBLE && to_al->sym &&
|
| 1172 | from_al->sym == to_al->sym &&
|
| 1173 | to_al->addr != to_al->sym->start)
|
| 1174 | ts->rstate = X86_RETPOLINE_DETECTED;
|
| 1175 |
|
| 1176 | } else if (sample->flags & PERF_IP_FLAG_RETURN) {
|
| 1177 | if (!sample->addr) {
|
| 1178 | u32 return_from_kernel = PERF_IP_FLAG_SYSCALLRET |
|
| 1179 | PERF_IP_FLAG_INTERRUPT;
|
| 1180 |
|
| 1181 | if (!(sample->flags & return_from_kernel))
|
| 1182 | return 0;
|
| 1183 |
|
| 1184 |
|
| 1185 | return thread_stack__pop_ks(thread, ts, sample, ref);
|
| 1186 | }
|
| 1187 |
|
| 1188 | if (!sample->ip)
|
| 1189 | return 0;
|
| 1190 |
|
| 1191 |
|
| 1192 | if (rstate == X86_RETPOLINE_DETECTED && ts->cnt > 2 &&
|
| 1193 | ts->stack[ts->cnt - 1].ret_addr != sample->addr)
|
| 1194 | return thread_stack__x86_retpoline(ts, sample, to_al);
|
| 1195 |
|
| 1196 | err = thread_stack__pop_cp(thread, ts, sample->addr,
|
| 1197 | sample->time, ref, from_al->sym);
|
| 1198 | if (err) {
|
| 1199 | if (err < 0)
|
| 1200 | return err;
|
| 1201 | err = thread_stack__no_call_return(thread, ts, sample,
|
| 1202 | from_al, to_al, ref);
|
| 1203 | }
|
| 1204 | } else if (sample->flags & PERF_IP_FLAG_TRACE_BEGIN) {
|
| 1205 | err = thread_stack__trace_begin(thread, ts, sample->time, ref);
|
| 1206 | } else if (sample->flags & PERF_IP_FLAG_TRACE_END) {
|
| 1207 | err = thread_stack__trace_end(ts, sample, ref);
|
| 1208 | } else if (sample->flags & PERF_IP_FLAG_BRANCH &&
|
| 1209 | from_al->sym != to_al->sym && to_al->sym &&
|
| 1210 | to_al->addr == to_al->sym->start) {
|
| 1211 | struct call_path_root *cpr = ts->crp->cpr;
|
| 1212 | struct call_path *cp;
|
| 1213 |
|
| 1214 | |
| 1215 | * The compiler might optimize a call/ret combination by making
|
| 1216 | * it a jmp. Make that visible by recording on the stack a
|
| 1217 | * branch to the start of a different symbol. Note, that means
|
| 1218 | * when a ret pops the stack, all jmps must be popped off first.
|
| 1219 |
|
| 1220 | cp = call_path__findnew(cpr, ts->stack[ts->cnt - 1].cp,
|
| 1221 | to_al->sym, sample->addr,
|
| 1222 | ts->kernel_start);
|
| 1223 | err = thread_stack__push_cp(ts, 0, sample->time, ref, cp, false,
|
| 1224 | false);
|
| 1225 | if (!err)
|
| 1226 | ts->stack[ts->cnt - 1].non_call = true;
|
| 1227 | }
|
| 1228 |
|
| 1229 | return err;
|
| 1230 | }
|
| 1231 |
|
| 1232 | size_t thread_stack__depth(struct thread *thread, int cpu)
|
| 1233 | {
|
| 1234 | struct thread_stack *ts = thread__stack(thread, cpu);
|
| 1235 |
|
| 1236 | if (!ts)
|
| 1237 | return 0;
|
| 1238 | return ts->cnt;
|
| 1239 | }
|