tools/testing/selftests/bpf/progs/pyperf.h

   1 // SPDX-License-Identifier: GPL-2.0
   2 // Copyright (c) 2019 Facebook
   3 #include <linux/sched.h>
   4 #include <linux/ptrace.h>
   5 #include <stdint.h>
   6 #include <stddef.h>
   7 #include <stdbool.h>
   8 #include <linux/bpf.h>
   9 #include "bpf_helpers.h"
  10
  11 #define FUNCTION_NAME_LEN 64
  12 #define FILE_NAME_LEN 128
  13 #define TASK_COMM_LEN 16
  14
  15 typedef struct {
  16         int PyThreadState_frame;
  17         int PyThreadState_thread;
  18         int PyFrameObject_back;
  19         int PyFrameObject_code;
  20         int PyFrameObject_lineno;
  21         int PyCodeObject_filename;
  22         int PyCodeObject_name;
  23         int String_data;
  24         int String_size;
  25 } OffsetConfig;
  26
  27 typedef struct {
  28         uintptr_t current_state_addr;
  29         uintptr_t tls_key_addr;
  30         OffsetConfig offsets;
  31         bool use_tls;
  32 } PidData;
  33
  34 typedef struct {
  35         uint32_t success;
  36 } Stats;
  37
  38 typedef struct {
  39         char name[FUNCTION_NAME_LEN];
  40         char file[FILE_NAME_LEN];
  41 } Symbol;
  42
  43 typedef struct {
  44         uint32_t pid;
  45         uint32_t tid;
  46         char comm[TASK_COMM_LEN];
  47         int32_t kernel_stack_id;
  48         int32_t user_stack_id;
  49         bool thread_current;
  50         bool pthread_match;
  51         bool stack_complete;
  52         int16_t stack_len;
  53         int32_t stack[STACK_MAX_LEN];
  54
  55         int has_meta;
  56         int metadata;
  57         char dummy_safeguard;
  58 } Event;
  59
  60
  61 typedef int pid_t;
  62
  63 typedef struct {
  64         void* f_back; // PyFrameObject.f_back, previous frame
  65         void* f_code; // PyFrameObject.f_code, pointer to PyCodeObject
  66         void* co_filename; // PyCodeObject.co_filename
  67         void* co_name; // PyCodeObject.co_name
  68 } FrameData;
  69
  70 static __always_inline void *get_thread_state(void *tls_base, PidData *pidData)
  71 {
  72         void* thread_state;
  73         int key;
  74
  75         bpf_probe_read(&key, sizeof(key), (void*)(long)pidData->tls_key_addr);
  76         bpf_probe_read(&thread_state, sizeof(thread_state),
  77                        tls_base + 0x310 + key * 0x10 + 0x08);
  78         return thread_state;
  79 }
  80
  81 static __always_inline bool get_frame_data(void *frame_ptr, PidData *pidData,
  82                                            FrameData *frame, Symbol *symbol)
  83 {
  84         // read data from PyFrameObject
  85         bpf_probe_read(&frame->f_back,
  86                        sizeof(frame->f_back),
  87                        frame_ptr + pidData->offsets.PyFrameObject_back);
  88         bpf_probe_read(&frame->f_code,
  89                        sizeof(frame->f_code),
  90                        frame_ptr + pidData->offsets.PyFrameObject_code);
  91
  92         // read data from PyCodeObject
  93         if (!frame->f_code)
  94                 return false;
  95         bpf_probe_read(&frame->co_filename,
  96                        sizeof(frame->co_filename),
  97                        frame->f_code + pidData->offsets.PyCodeObject_filename);
  98         bpf_probe_read(&frame->co_name,
  99                        sizeof(frame->co_name),
 100                        frame->f_code + pidData->offsets.PyCodeObject_name);
 101         // read actual names into symbol
 102         if (frame->co_filename)
 103                 bpf_probe_read_str(&symbol->file,
 104                                    sizeof(symbol->file),
 105                                    frame->co_filename + pidData->offsets.String_data);
 106         if (frame->co_name)
 107                 bpf_probe_read_str(&symbol->name,
 108                                    sizeof(symbol->name),
 109                                    frame->co_name + pidData->offsets.String_data);
 110         return true;
 111 }
 112
 113 struct {
 114         __uint(type, BPF_MAP_TYPE_HASH);
 115         __uint(max_entries, 1);
 116         __type(key, int);
 117         __type(value, PidData);
 118 } pidmap SEC(".maps");
 119
 120 struct {
 121         __uint(type, BPF_MAP_TYPE_HASH);
 122         __uint(max_entries, 1);
 123         __type(key, int);
 124         __type(value, Event);
 125 } eventmap SEC(".maps");
 126
 127 struct {
 128         __uint(type, BPF_MAP_TYPE_HASH);
 129         __uint(max_entries, 1);
 130         __type(key, Symbol);
 131         __type(value, int);
 132 } symbolmap SEC(".maps");
 133
 134 struct {
 135         __uint(type, BPF_MAP_TYPE_ARRAY);
 136         __uint(max_entries, 1);
 137         __type(key, int);
 138         __type(value, Stats);
 139 } statsmap SEC(".maps");
 140
 141 struct {
 142         __uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);
 143         __uint(max_entries, 32);
 144         __uint(key_size, sizeof(int));
 145         __uint(value_size, sizeof(int));
 146 } perfmap SEC(".maps");
 147
 148 struct {
 149         __uint(type, BPF_MAP_TYPE_STACK_TRACE);
 150         __uint(max_entries, 1000);
 151         __uint(key_size, sizeof(int));
 152         __uint(value_size, sizeof(long long) * 127);
 153 } stackmap SEC(".maps");
 154
 155 static __always_inline int __on_event(struct pt_regs *ctx)
 156 {
 157         uint64_t pid_tgid = bpf_get_current_pid_tgid();
 158         pid_t pid = (pid_t)(pid_tgid >> 32);
 159         PidData* pidData = bpf_map_lookup_elem(&pidmap, &pid);
 160         if (!pidData)
 161                 return 0;
 162
 163         int zero = 0;
 164         Event* event = bpf_map_lookup_elem(&eventmap, &zero);
 165         if (!event)
 166                 return 0;
 167
 168         event->pid = pid;
 169
 170         event->tid = (pid_t)pid_tgid;
 171         bpf_get_current_comm(&event->comm, sizeof(event->comm));
 172
 173         event->user_stack_id = bpf_get_stackid(ctx, &stackmap, BPF_F_USER_STACK);
 174         event->kernel_stack_id = bpf_get_stackid(ctx, &stackmap, 0);
 175
 176         void* thread_state_current = (void*)0;
 177         bpf_probe_read(&thread_state_current,
 178                        sizeof(thread_state_current),
 179                        (void*)(long)pidData->current_state_addr);
 180
 181         struct task_struct* task = (struct task_struct*)bpf_get_current_task();
 182         void* tls_base = (void*)task;
 183
 184         void* thread_state = pidData->use_tls ? get_thread_state(tls_base, pidData)
 185                 : thread_state_current;
 186         event->thread_current = thread_state == thread_state_current;
 187
 188         if (pidData->use_tls) {
 189                 uint64_t pthread_created;
 190                 uint64_t pthread_self;
 191                 bpf_probe_read(&pthread_self, sizeof(pthread_self), tls_base + 0x10);
 192
 193                 bpf_probe_read(&pthread_created,
 194                                sizeof(pthread_created),
 195                                thread_state + pidData->offsets.PyThreadState_thread);
 196                 event->pthread_match = pthread_created == pthread_self;
 197         } else {
 198                 event->pthread_match = 1;
 199         }
 200
 201         if (event->pthread_match || !pidData->use_tls) {
 202                 void* frame_ptr;
 203                 FrameData frame;
 204                 Symbol sym = {};
 205                 int cur_cpu = bpf_get_smp_processor_id();
 206
 207                 bpf_probe_read(&frame_ptr,
 208                                sizeof(frame_ptr),
 209                                thread_state + pidData->offsets.PyThreadState_frame);
 210
 211                 int32_t* symbol_counter = bpf_map_lookup_elem(&symbolmap, &sym);
 212                 if (symbol_counter == NULL)
 213                         return 0;
 214 #ifdef NO_UNROLL
 215 #pragma clang loop unroll(disable)
 216 #else
 217 #pragma clang loop unroll(full)
 218 #endif
 219                 /* Unwind python stack */
 220                 for (int i = 0; i < STACK_MAX_LEN; ++i) {
 221                         if (frame_ptr && get_frame_data(frame_ptr, pidData, &frame, &sym)) {
 222                                 int32_t new_symbol_id = *symbol_counter * 64 + cur_cpu;
 223                                 int32_t *symbol_id = bpf_map_lookup_elem(&symbolmap, &sym);
 224                                 if (!symbol_id) {
 225                                         bpf_map_update_elem(&symbolmap, &sym, &zero, 0);
 226                                         symbol_id = bpf_map_lookup_elem(&symbolmap, &sym);
 227                                         if (!symbol_id)
 228                                                 return 0;
 229                                 }
 230                                 if (*symbol_id == new_symbol_id)
 231                                         (*symbol_counter)++;
 232                                 event->stack[i] = *symbol_id;
 233                                 event->stack_len = i + 1;
 234                                 frame_ptr = frame.f_back;
 235                         }
 236                 }
 237                 event->stack_complete = frame_ptr == NULL;
 238         } else {
 239                 event->stack_complete = 1;
 240         }
 241
 242         Stats* stats = bpf_map_lookup_elem(&statsmap, &zero);
 243         if (stats)
 244                 stats->success++;
 245
 246         event->has_meta = 0;
 247         bpf_perf_event_output(ctx, &perfmap, 0, event, offsetof(Event, metadata));
 248         return 0;
 249 }
 250
 251 SEC("raw_tracepoint/kfree_skb")
 252 int on_event(struct pt_regs* ctx)
 253 {
 254         int i, ret = 0;
 255         ret |= __on_event(ctx);
 256         ret |= __on_event(ctx);
 257         ret |= __on_event(ctx);
 258         ret |= __on_event(ctx);
 259         ret |= __on_event(ctx);
 260         return ret;
 261 }
 262
 263 char _license[] SEC("license") = "GPL";