lib/trace.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Copyright (c) 2012 The Chromium OS Authors.
   4  */
   5
   6 #include <common.h>
   7 #include <mapmem.h>
   8 #include <time.h>
   9 #include <trace.h>
  10 #include <asm/io.h>
  11 #include <asm/sections.h>
  12
  13 DECLARE_GLOBAL_DATA_PTR;
  14
  15 static char trace_enabled __attribute__((section(".data")));
  16 static char trace_inited __attribute__((section(".data")));
  17
  18 /* The header block at the start of the trace memory area */
  19 struct trace_hdr {
  20         int func_count;         /* Total number of function call sites */
  21         u64 call_count;         /* Total number of tracked function calls */
  22         u64 untracked_count;    /* Total number of untracked function calls */
  23         int funcs_used;         /* Total number of functions used */
  24
  25         /*
  26          * Call count for each function. This is indexed by the word offset
  27          * of the function from gd->relocaddr
  28          */
  29         uintptr_t *call_accum;
  30
  31         /* Function trace list */
  32         struct trace_call *ftrace;      /* The function call records */
  33         ulong ftrace_size;      /* Num. of ftrace records we have space for */
  34         ulong ftrace_count;     /* Num. of ftrace records written */
  35         ulong ftrace_too_deep_count;    /* Functions that were too deep */
  36
  37         int depth;
  38         int depth_limit;
  39         int max_depth;
  40 };
  41
  42 static struct trace_hdr *hdr;   /* Pointer to start of trace buffer */
  43
  44 static inline uintptr_t __attribute__((no_instrument_function))
  45                 func_ptr_to_num(void *func_ptr)
  46 {
  47         uintptr_t offset = (uintptr_t)func_ptr;
  48
  49 #ifdef CONFIG_SANDBOX
  50         offset -= (uintptr_t)&_init;
  51 #else
  52         if (gd->flags & GD_FLG_RELOC)
  53                 offset -= gd->relocaddr;
  54         else
  55                 offset -= CONFIG_SYS_TEXT_BASE;
  56 #endif
  57         return offset / FUNC_SITE_SIZE;
  58 }
  59
  60 #if defined(CONFIG_EFI_LOADER) && defined(CONFIG_ARM)
  61
  62 /**
  63  * trace_gd - the value of the gd register
  64  */
  65 static volatile gd_t *trace_gd;
  66
  67 /**
  68  * trace_save_gd() - save the value of the gd register
  69  */
  70 static void __attribute__((no_instrument_function)) trace_save_gd(void)
  71 {
  72         trace_gd = gd;
  73 }
  74
  75 /**
  76  * trace_swap_gd() - swap between U-Boot and application gd register value
  77  *
  78  * An UEFI application may change the value of the register that gd lives in.
  79  * But some of our functions like get_ticks() access this register. So we
  80  * have to set the gd register to the U-Boot value when entering a trace
  81  * point and set it back to the application value when exiting the trace point.
  82  */
  83 static void __attribute__((no_instrument_function)) trace_swap_gd(void)
  84 {
  85         volatile gd_t *temp_gd = trace_gd;
  86
  87         trace_gd = gd;
  88         set_gd(temp_gd);
  89 }
  90
  91 #else
  92
  93 static void __attribute__((no_instrument_function)) trace_save_gd(void)
  94 {
  95 }
  96
  97 static void __attribute__((no_instrument_function)) trace_swap_gd(void)
  98 {
  99 }
 100
 101 #endif
 102
 103 static void __attribute__((no_instrument_function)) add_ftrace(void *func_ptr,
 104                                 void *caller, ulong flags)
 105 {
 106         if (hdr->depth > hdr->depth_limit) {
 107                 hdr->ftrace_too_deep_count++;
 108                 return;
 109         }
 110         if (hdr->ftrace_count < hdr->ftrace_size) {
 111                 struct trace_call *rec = &hdr->ftrace[hdr->ftrace_count];
 112
 113                 rec->func = func_ptr_to_num(func_ptr);
 114                 rec->caller = func_ptr_to_num(caller);
 115                 rec->flags = flags | (timer_get_us() & FUNCF_TIMESTAMP_MASK);
 116         }
 117         hdr->ftrace_count++;
 118 }
 119
 120 static void __attribute__((no_instrument_function)) add_textbase(void)
 121 {
 122         if (hdr->ftrace_count < hdr->ftrace_size) {
 123                 struct trace_call *rec = &hdr->ftrace[hdr->ftrace_count];
 124
 125                 rec->func = CONFIG_SYS_TEXT_BASE;
 126                 rec->caller = 0;
 127                 rec->flags = FUNCF_TEXTBASE;
 128         }
 129         hdr->ftrace_count++;
 130 }
 131
 132 /**
 133  * __cyg_profile_func_enter() - record function entry
 134  *
 135  * We add to our tally for this function and add to the list of called
 136  * functions.
 137  *
 138  * @func_ptr:   pointer to function being entered
 139  * @caller:     pointer to function which called this function
 140  */
 141 void __attribute__((no_instrument_function)) __cyg_profile_func_enter(
 142                 void *func_ptr, void *caller)
 143 {
 144         if (trace_enabled) {
 145                 int func;
 146
 147                 trace_swap_gd();
 148                 add_ftrace(func_ptr, caller, FUNCF_ENTRY);
 149                 func = func_ptr_to_num(func_ptr);
 150                 if (func < hdr->func_count) {
 151                         hdr->call_accum[func]++;
 152                         hdr->call_count++;
 153                 } else {
 154                         hdr->untracked_count++;
 155                 }
 156                 hdr->depth++;
 157                 if (hdr->depth > hdr->depth_limit)
 158                         hdr->max_depth = hdr->depth;
 159                 trace_swap_gd();
 160         }
 161 }
 162
 163 /**
 164  * __cyg_profile_func_exit() - record function exit
 165  *
 166  * @func_ptr:   pointer to function being entered
 167  * @caller:     pointer to function which called this function
 168  */
 169 void __attribute__((no_instrument_function)) __cyg_profile_func_exit(
 170                 void *func_ptr, void *caller)
 171 {
 172         if (trace_enabled) {
 173                 trace_swap_gd();
 174                 add_ftrace(func_ptr, caller, FUNCF_EXIT);
 175                 hdr->depth--;
 176                 trace_swap_gd();
 177         }
 178 }
 179
 180 /**
 181  * trace_list_functions() - produce a list of called functions
 182  *
 183  * The information is written into the supplied buffer - a header followed
 184  * by a list of function records.
 185  *
 186  * @buff:       buffer to place list into
 187  * @buff_size:  size of buffer
 188  * @needed:     returns size of buffer needed, which may be
 189  *              greater than buff_size if we ran out of space.
 190  * Return:      0 if ok, -ENOSPC if space was exhausted
 191  */
 192 int trace_list_functions(void *buff, size_t buff_size, size_t *needed)
 193 {
 194         struct trace_output_hdr *output_hdr = NULL;
 195         void *end, *ptr = buff;
 196         size_t func;
 197         size_t upto;
 198
 199         end = buff ? buff + buff_size : NULL;
 200
 201         /* Place some header information */
 202         if (ptr + sizeof(struct trace_output_hdr) < end)
 203                 output_hdr = ptr;
 204         ptr += sizeof(struct trace_output_hdr);
 205
 206         /* Add information about each function */
 207         for (func = upto = 0; func < hdr->func_count; func++) {
 208                 size_t calls = hdr->call_accum[func];
 209
 210                 if (!calls)
 211                         continue;
 212
 213                 if (ptr + sizeof(struct trace_output_func) < end) {
 214                         struct trace_output_func *stats = ptr;
 215
 216                         stats->offset = func * FUNC_SITE_SIZE;
 217                         stats->call_count = calls;
 218                         upto++;
 219                 }
 220                 ptr += sizeof(struct trace_output_func);
 221         }
 222
 223         /* Update the header */
 224         if (output_hdr) {
 225                 output_hdr->rec_count = upto;
 226                 output_hdr->type = TRACE_CHUNK_FUNCS;
 227         }
 228
 229         /* Work out how must of the buffer we used */
 230         *needed = ptr - buff;
 231         if (ptr > end)
 232                 return -ENOSPC;
 233
 234         return 0;
 235 }
 236
 237 /**
 238  * trace_list_functions() - produce a list of function calls
 239  *
 240  * The information is written into the supplied buffer - a header followed
 241  * by a list of function records.
 242  *
 243  * @buff:       buffer to place list into
 244  * @buff_size:  size of buffer
 245  * @needed:     returns size of buffer needed, which may be
 246  *              greater than buff_size if we ran out of space.
 247  * Return:      0 if ok, -ENOSPC if space was exhausted
 248  */
 249 int trace_list_calls(void *buff, size_t buff_size, size_t *needed)
 250 {
 251         struct trace_output_hdr *output_hdr = NULL;
 252         void *end, *ptr = buff;
 253         size_t rec, upto;
 254         size_t count;
 255
 256         end = buff ? buff + buff_size : NULL;
 257
 258         /* Place some header information */
 259         if (ptr + sizeof(struct trace_output_hdr) < end)
 260                 output_hdr = ptr;
 261         ptr += sizeof(struct trace_output_hdr);
 262
 263         /* Add information about each call */
 264         count = hdr->ftrace_count;
 265         if (count > hdr->ftrace_size)
 266                 count = hdr->ftrace_size;
 267         for (rec = upto = 0; rec < count; rec++) {
 268                 if (ptr + sizeof(struct trace_call) < end) {
 269                         struct trace_call *call = &hdr->ftrace[rec];
 270                         struct trace_call *out = ptr;
 271
 272                         out->func = call->func * FUNC_SITE_SIZE;
 273                         out->caller = call->caller * FUNC_SITE_SIZE;
 274                         out->flags = call->flags;
 275                         upto++;
 276                 }
 277                 ptr += sizeof(struct trace_call);
 278         }
 279
 280         /* Update the header */
 281         if (output_hdr) {
 282                 output_hdr->rec_count = upto;
 283                 output_hdr->type = TRACE_CHUNK_CALLS;
 284         }
 285
 286         /* Work out how must of the buffer we used */
 287         *needed = ptr - buff;
 288         if (ptr > end)
 289                 return -ENOSPC;
 290
 291         return 0;
 292 }
 293
 294 /**
 295  * trace_print_stats() - print basic information about tracing
 296  */
 297 void trace_print_stats(void)
 298 {
 299         ulong count;
 300
 301 #ifndef FTRACE
 302         puts("Warning: make U-Boot with FTRACE to enable function instrumenting.\n");
 303         puts("You will likely get zeroed data here\n");
 304 #endif
 305         if (!trace_inited) {
 306                 printf("Trace is disabled\n");
 307                 return;
 308         }
 309         print_grouped_ull(hdr->func_count, 10);
 310         puts(" function sites\n");
 311         print_grouped_ull(hdr->call_count, 10);
 312         puts(" function calls\n");
 313         print_grouped_ull(hdr->untracked_count, 10);
 314         puts(" untracked function calls\n");
 315         count = min(hdr->ftrace_count, hdr->ftrace_size);
 316         print_grouped_ull(count, 10);
 317         puts(" traced function calls");
 318         if (hdr->ftrace_count > hdr->ftrace_size) {
 319                 printf(" (%lu dropped due to overflow)",
 320                        hdr->ftrace_count - hdr->ftrace_size);
 321         }
 322         puts("\n");
 323         printf("%15d maximum observed call depth\n", hdr->max_depth);
 324         printf("%15d call depth limit\n", hdr->depth_limit);
 325         print_grouped_ull(hdr->ftrace_too_deep_count, 10);
 326         puts(" calls not traced due to depth\n");
 327 }
 328
 329 void __attribute__((no_instrument_function)) trace_set_enabled(int enabled)
 330 {
 331         trace_enabled = enabled != 0;
 332 }
 333
 334 /**
 335  * trace_init() - initialize the tracing system and enable it
 336  *
 337  * @buff:       Pointer to trace buffer
 338  * @buff_size:  Size of trace buffer
 339  * Return:      0 if ok
 340  */
 341 int __attribute__((no_instrument_function)) trace_init(void *buff,
 342                 size_t buff_size)
 343 {
 344         ulong func_count = gd->mon_len / FUNC_SITE_SIZE;
 345         size_t needed;
 346         int was_disabled = !trace_enabled;
 347
 348         trace_save_gd();
 349
 350         if (!was_disabled) {
 351 #ifdef CONFIG_TRACE_EARLY
 352                 char *end;
 353                 ulong used;
 354
 355                 /*
 356                  * Copy over the early trace data if we have it. Disable
 357                  * tracing while we are doing this.
 358                  */
 359                 trace_enabled = 0;
 360                 hdr = map_sysmem(CONFIG_TRACE_EARLY_ADDR,
 361                                  CONFIG_TRACE_EARLY_SIZE);
 362                 end = (char *)&hdr->ftrace[min(hdr->ftrace_count,
 363                                                hdr->ftrace_size)];
 364                 used = end - (char *)hdr;
 365                 printf("trace: copying %08lx bytes of early data from %x to %08lx\n",
 366                        used, CONFIG_TRACE_EARLY_ADDR,
 367                        (ulong)map_to_sysmem(buff));
 368                 memcpy(buff, hdr, used);
 369 #else
 370                 puts("trace: already enabled\n");
 371                 return -EALREADY;
 372 #endif
 373         }
 374         hdr = (struct trace_hdr *)buff;
 375         needed = sizeof(*hdr) + func_count * sizeof(uintptr_t);
 376         if (needed > buff_size) {
 377                 printf("trace: buffer size %zd bytes: at least %zd needed\n",
 378                        buff_size, needed);
 379                 return -ENOSPC;
 380         }
 381
 382         if (was_disabled)
 383                 memset(hdr, '\0', needed);
 384         hdr->func_count = func_count;
 385         hdr->call_accum = (uintptr_t *)(hdr + 1);
 386
 387         /* Use any remaining space for the timed function trace */
 388         hdr->ftrace = (struct trace_call *)(buff + needed);
 389         hdr->ftrace_size = (buff_size - needed) / sizeof(*hdr->ftrace);
 390         add_textbase();
 391
 392         puts("trace: enabled\n");
 393         hdr->depth_limit = CONFIG_TRACE_CALL_DEPTH_LIMIT;
 394         trace_enabled = 1;
 395         trace_inited = 1;
 396
 397         return 0;
 398 }
 399
 400 #ifdef CONFIG_TRACE_EARLY
 401 /**
 402  * trace_early_init() - initialize the tracing system for early tracing
 403  *
 404  * Return:      0 if ok, -ENOSPC if not enough memory is available
 405  */
 406 int __attribute__((no_instrument_function)) trace_early_init(void)
 407 {
 408         ulong func_count = gd->mon_len / FUNC_SITE_SIZE;
 409         size_t buff_size = CONFIG_TRACE_EARLY_SIZE;
 410         size_t needed;
 411
 412         /* We can ignore additional calls to this function */
 413         if (trace_enabled)
 414                 return 0;
 415
 416         hdr = map_sysmem(CONFIG_TRACE_EARLY_ADDR, CONFIG_TRACE_EARLY_SIZE);
 417         needed = sizeof(*hdr) + func_count * sizeof(uintptr_t);
 418         if (needed > buff_size) {
 419                 printf("trace: buffer size is %zd bytes, at least %zd needed\n",
 420                        buff_size, needed);
 421                 return -ENOSPC;
 422         }
 423
 424         memset(hdr, '\0', needed);
 425         hdr->call_accum = (uintptr_t *)(hdr + 1);
 426         hdr->func_count = func_count;
 427
 428         /* Use any remaining space for the timed function trace */
 429         hdr->ftrace = (struct trace_call *)((char *)hdr + needed);
 430         hdr->ftrace_size = (buff_size - needed) / sizeof(*hdr->ftrace);
 431         add_textbase();
 432         hdr->depth_limit = CONFIG_TRACE_EARLY_CALL_DEPTH_LIMIT;
 433         printf("trace: early enable at %08x\n", CONFIG_TRACE_EARLY_ADDR);
 434
 435         trace_enabled = 1;
 436
 437         return 0;
 438 }
 439 #endif