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/bpf_helpers.h>
  10 #include "bpf_misc.h"
  11
  12 #define FUNCTION_NAME_LEN 64
  13 #define FILE_NAME_LEN 128
  14 #define TASK_COMM_LEN 16
  15
  16 typedef struct {
  17         int PyThreadState_frame;
  18         int PyThreadState_thread;
  19         int PyFrameObject_back;
  20         int PyFrameObject_code;
  21         int PyFrameObject_lineno;
  22         int PyCodeObject_filename;
  23         int PyCodeObject_name;
  24         int String_data;
  25         int String_size;
  26 } OffsetConfig;
  27
  28 typedef struct {
  29         uintptr_t current_state_addr;
  30         uintptr_t tls_key_addr;
  31         OffsetConfig offsets;
  32         bool use_tls;
  33 } PidData;
  34
  35 typedef struct {
  36         uint32_t success;
  37 } Stats;
  38
  39 typedef struct {
  40         char name[FUNCTION_NAME_LEN];
  41         char file[FILE_NAME_LEN];
  42 } Symbol;
  43
  44 typedef struct {
  45         uint32_t pid;
  46         uint32_t tid;
  47         char comm[TASK_COMM_LEN];
  48         int32_t kernel_stack_id;
  49         int32_t user_stack_id;
  50         bool thread_current;
  51         bool pthread_match;
  52         bool stack_complete;
  53         int16_t stack_len;
  54         int32_t stack[STACK_MAX_LEN];
  55
  56         int has_meta;
  57         int metadata;
  58         char dummy_safeguard;
  59 } Event;
  60
  61
  62 typedef int pid_t;
  63
  64 typedef struct {
  65         void* f_back; // PyFrameObject.f_back, previous frame
  66         void* f_code; // PyFrameObject.f_code, pointer to PyCodeObject
  67         void* co_filename; // PyCodeObject.co_filename
  68         void* co_name; // PyCodeObject.co_name
  69 } FrameData;
  70
  71 #ifdef SUBPROGS
  72 __noinline
  73 #else
  74 __always_inline
  75 #endif
  76 static void *get_thread_state(void *tls_base, PidData *pidData)
  77 {
  78         void* thread_state;
  79         int key;
  80
  81         bpf_probe_read_user(&key, sizeof(key), (void*)(long)pidData->tls_key_addr);
  82         bpf_probe_read_user(&thread_state, sizeof(thread_state),
  83                             tls_base + 0x310 + key * 0x10 + 0x08);
  84         return thread_state;
  85 }
  86
  87 static __always_inline bool get_frame_data(void *frame_ptr, PidData *pidData,
  88                                            FrameData *frame, Symbol *symbol)
  89 {
  90         // read data from PyFrameObject
  91         bpf_probe_read_user(&frame->f_back,
  92                             sizeof(frame->f_back),
  93                             frame_ptr + pidData->offsets.PyFrameObject_back);
  94         bpf_probe_read_user(&frame->f_code,
  95                             sizeof(frame->f_code),
  96                             frame_ptr + pidData->offsets.PyFrameObject_code);
  97
  98         // read data from PyCodeObject
  99         if (!frame->f_code)
 100                 return false;
 101         bpf_probe_read_user(&frame->co_filename,
 102                             sizeof(frame->co_filename),
 103                             frame->f_code + pidData->offsets.PyCodeObject_filename);
 104         bpf_probe_read_user(&frame->co_name,
 105                             sizeof(frame->co_name),
 106                             frame->f_code + pidData->offsets.PyCodeObject_name);
 107         // read actual names into symbol
 108         if (frame->co_filename)
 109                 bpf_probe_read_user_str(&symbol->file,
 110                                         sizeof(symbol->file),
 111                                         frame->co_filename +
 112                                         pidData->offsets.String_data);
 113         if (frame->co_name)
 114                 bpf_probe_read_user_str(&symbol->name,
 115                                         sizeof(symbol->name),
 116                                         frame->co_name +
 117                                         pidData->offsets.String_data);
 118         return true;
 119 }
 120
 121 struct {
 122         __uint(type, BPF_MAP_TYPE_HASH);
 123         __uint(max_entries, 1);
 124         __type(key, int);
 125         __type(value, PidData);
 126 } pidmap SEC(".maps");
 127
 128 struct {
 129         __uint(type, BPF_MAP_TYPE_HASH);
 130         __uint(max_entries, 1);
 131         __type(key, int);
 132         __type(value, Event);
 133 } eventmap SEC(".maps");
 134
 135 struct {
 136         __uint(type, BPF_MAP_TYPE_HASH);
 137         __uint(max_entries, 1);
 138         __type(key, Symbol);
 139         __type(value, int);
 140 } symbolmap SEC(".maps");
 141
 142 struct {
 143         __uint(type, BPF_MAP_TYPE_ARRAY);
 144         __uint(max_entries, 1);
 145         __type(key, int);
 146         __type(value, Stats);
 147 } statsmap SEC(".maps");
 148
 149 struct {
 150         __uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);
 151         __uint(max_entries, 32);
 152         __uint(key_size, sizeof(int));
 153         __uint(value_size, sizeof(int));
 154 } perfmap SEC(".maps");
 155
 156 struct {
 157         __uint(type, BPF_MAP_TYPE_STACK_TRACE);
 158         __uint(max_entries, 1000);
 159         __uint(key_size, sizeof(int));
 160         __uint(value_size, sizeof(long long) * 127);
 161 } stackmap SEC(".maps");
 162
 163 #ifdef USE_BPF_LOOP
 164 struct process_frame_ctx {
 165         int cur_cpu;
 166         int32_t *symbol_counter;
 167         void *frame_ptr;
 168         FrameData *frame;
 169         PidData *pidData;
 170         Symbol *sym;
 171         Event *event;
 172         bool done;
 173 };
 174
 175 static int process_frame_callback(__u32 i, struct process_frame_ctx *ctx)
 176 {
 177         int zero = 0;
 178         void *frame_ptr = ctx->frame_ptr;
 179         PidData *pidData = ctx->pidData;
 180         FrameData *frame = ctx->frame;
 181         int32_t *symbol_counter = ctx->symbol_counter;
 182         int cur_cpu = ctx->cur_cpu;
 183         Event *event = ctx->event;
 184         Symbol *sym = ctx->sym;
 185
 186         if (frame_ptr && get_frame_data(frame_ptr, pidData, frame, sym)) {
 187                 int32_t new_symbol_id = *symbol_counter * 64 + cur_cpu;
 188                 int32_t *symbol_id = bpf_map_lookup_elem(&symbolmap, sym);
 189
 190                 if (!symbol_id) {
 191                         bpf_map_update_elem(&symbolmap, sym, &zero, 0);
 192                         symbol_id = bpf_map_lookup_elem(&symbolmap, sym);
 193                         if (!symbol_id) {
 194                                 ctx->done = true;
 195                                 return 1;
 196                         }
 197                 }
 198                 if (*symbol_id == new_symbol_id)
 199                         (*symbol_counter)++;
 200
 201                 barrier_var(i);
 202                 if (i >= STACK_MAX_LEN)
 203                         return 1;
 204
 205                 event->stack[i] = *symbol_id;
 206
 207                 event->stack_len = i + 1;
 208                 frame_ptr = frame->f_back;
 209         }
 210         return 0;
 211 }
 212 #endif /* USE_BPF_LOOP */
 213
 214 #ifdef GLOBAL_FUNC
 215 __noinline
 216 #elif defined(SUBPROGS)
 217 static __noinline
 218 #else
 219 static __always_inline
 220 #endif
 221 int __on_event(struct bpf_raw_tracepoint_args *ctx)
 222 {
 223         uint64_t pid_tgid = bpf_get_current_pid_tgid();
 224         pid_t pid = (pid_t)(pid_tgid >> 32);
 225         PidData* pidData = bpf_map_lookup_elem(&pidmap, &pid);
 226         if (!pidData)
 227                 return 0;
 228
 229         int zero = 0;
 230         Event* event = bpf_map_lookup_elem(&eventmap, &zero);
 231         if (!event)
 232                 return 0;
 233
 234         event->pid = pid;
 235
 236         event->tid = (pid_t)pid_tgid;
 237         bpf_get_current_comm(&event->comm, sizeof(event->comm));
 238
 239         event->user_stack_id = bpf_get_stackid(ctx, &stackmap, BPF_F_USER_STACK);
 240         event->kernel_stack_id = bpf_get_stackid(ctx, &stackmap, 0);
 241
 242         void* thread_state_current = (void*)0;
 243         bpf_probe_read_user(&thread_state_current,
 244                             sizeof(thread_state_current),
 245                             (void*)(long)pidData->current_state_addr);
 246
 247         struct task_struct* task = (struct task_struct*)bpf_get_current_task();
 248         void* tls_base = (void*)task;
 249
 250         void* thread_state = pidData->use_tls ? get_thread_state(tls_base, pidData)
 251                 : thread_state_current;
 252         event->thread_current = thread_state == thread_state_current;
 253
 254         if (pidData->use_tls) {
 255                 uint64_t pthread_created;
 256                 uint64_t pthread_self;
 257                 bpf_probe_read_user(&pthread_self, sizeof(pthread_self),
 258                                     tls_base + 0x10);
 259
 260                 bpf_probe_read_user(&pthread_created,
 261                                     sizeof(pthread_created),
 262                                     thread_state +
 263                                     pidData->offsets.PyThreadState_thread);
 264                 event->pthread_match = pthread_created == pthread_self;
 265         } else {
 266                 event->pthread_match = 1;
 267         }
 268
 269         if (event->pthread_match || !pidData->use_tls) {
 270                 void* frame_ptr;
 271                 FrameData frame;
 272                 Symbol sym = {};
 273                 int cur_cpu = bpf_get_smp_processor_id();
 274
 275                 bpf_probe_read_user(&frame_ptr,
 276                                     sizeof(frame_ptr),
 277                                     thread_state +
 278                                     pidData->offsets.PyThreadState_frame);
 279
 280                 int32_t* symbol_counter = bpf_map_lookup_elem(&symbolmap, &sym);
 281                 if (symbol_counter == NULL)
 282                         return 0;
 283 #ifdef USE_BPF_LOOP
 284         struct process_frame_ctx ctx = {
 285                 .cur_cpu = cur_cpu,
 286                 .symbol_counter = symbol_counter,
 287                 .frame_ptr = frame_ptr,
 288                 .frame = &frame,
 289                 .pidData = pidData,
 290                 .sym = &sym,
 291                 .event = event,
 292         };
 293
 294         bpf_loop(STACK_MAX_LEN, process_frame_callback, &ctx, 0);
 295         if (ctx.done)
 296                 return 0;
 297 #else
 298 #if defined(USE_ITER)
 299 /* no for loop, no unrolling */
 300 #elif defined(NO_UNROLL)
 301 #pragma clang loop unroll(disable)
 302 #elif defined(UNROLL_COUNT)
 303 #pragma clang loop unroll_count(UNROLL_COUNT)
 304 #else
 305 #pragma clang loop unroll(full)
 306 #endif /* NO_UNROLL */
 307                 /* Unwind python stack */
 308 #ifdef USE_ITER
 309                 int i;
 310                 bpf_for(i, 0, STACK_MAX_LEN) {
 311 #else /* !USE_ITER */
 312                 for (int i = 0; i < STACK_MAX_LEN; ++i) {
 313 #endif
 314                         if (frame_ptr && get_frame_data(frame_ptr, pidData, &frame, &sym)) {
 315                                 int32_t new_symbol_id = *symbol_counter * 64 + cur_cpu;
 316                                 int32_t *symbol_id = bpf_map_lookup_elem(&symbolmap, &sym);
 317                                 if (!symbol_id) {
 318                                         bpf_map_update_elem(&symbolmap, &sym, &zero, 0);
 319                                         symbol_id = bpf_map_lookup_elem(&symbolmap, &sym);
 320                                         if (!symbol_id)
 321                                                 return 0;
 322                                 }
 323                                 if (*symbol_id == new_symbol_id)
 324                                         (*symbol_counter)++;
 325                                 event->stack[i] = *symbol_id;
 326                                 event->stack_len = i + 1;
 327                                 frame_ptr = frame.f_back;
 328                         }
 329                 }
 330 #endif /* USE_BPF_LOOP */
 331                 event->stack_complete = frame_ptr == NULL;
 332         } else {
 333                 event->stack_complete = 1;
 334         }
 335
 336         Stats* stats = bpf_map_lookup_elem(&statsmap, &zero);
 337         if (stats)
 338                 stats->success++;
 339
 340         event->has_meta = 0;
 341         bpf_perf_event_output(ctx, &perfmap, 0, event, offsetof(Event, metadata));
 342         return 0;
 343 }
 344
 345 SEC("raw_tracepoint/kfree_skb")
 346 int on_event(struct bpf_raw_tracepoint_args* ctx)
 347 {
 348         int ret = 0;
 349         ret |= __on_event(ctx);
 350         ret |= __on_event(ctx);
 351         ret |= __on_event(ctx);
 352         ret |= __on_event(ctx);
 353         ret |= __on_event(ctx);
 354         return ret;
 355 }
 356
 357 char _license[] SEC("license") = "GPL";