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