summaryrefslogtreecommitdiff
path: root/lib/trace.c
blob: 1091a5793a1cab6523e7082a0009c8e874c1b6e8 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
// SPDX-License-Identifier: GPL-2.0+
/*
 * Copyright (c) 2012 The Chromium OS Authors.
 */

#include <common.h>
#include <mapmem.h>
#include <time.h>
#include <trace.h>
#include <asm/global_data.h>
#include <asm/io.h>
#include <asm/sections.h>

DECLARE_GLOBAL_DATA_PTR;

static char trace_enabled __section(".data");
static char trace_inited __section(".data");

/* The header block at the start of the trace memory area */
struct trace_hdr {
	int func_count;		/* Total number of function call sites */
	u64 call_count;		/* Total number of tracked function calls */
	u64 untracked_count;	/* Total number of untracked function calls */
	int funcs_used;		/* Total number of functions used */

	/*
	 * Call count for each function. This is indexed by the word offset
	 * of the function from gd->relocaddr
	 */
	uintptr_t *call_accum;

	/* Function trace list */
	struct trace_call *ftrace;	/* The function call records */
	ulong ftrace_size;	/* Num. of ftrace records we have space for */
	ulong ftrace_count;	/* Num. of ftrace records written */
	ulong ftrace_too_deep_count;	/* Functions that were too deep */

	int depth;		/* Depth of function calls */
	int depth_limit;	/* Depth limit to trace to */
	int max_depth;		/* Maximum depth seen so far */
	int min_depth;		/* Minimum depth seen so far */
	bool trace_locked;	/* Used to detect recursive tracing */
};

/* Pointer to start of trace buffer */
static struct trace_hdr *hdr __section(".data");

static inline uintptr_t __attribute__((no_instrument_function))
		func_ptr_to_num(void *func_ptr)
{
	uintptr_t offset = (uintptr_t)func_ptr;

#ifdef CONFIG_SANDBOX
	offset -= (uintptr_t)&_init;
#else
	if (gd->flags & GD_FLG_RELOC)
		offset -= gd->relocaddr;
	else
		offset -= CONFIG_TEXT_BASE;
#endif
	return offset / FUNC_SITE_SIZE;
}

#if defined(CONFIG_EFI_LOADER) && (defined(CONFIG_ARM) || defined(CONFIG_RISCV))

/**
 * trace_gd - the value of the gd register
 */
static volatile gd_t *trace_gd;

/**
 * trace_save_gd() - save the value of the gd register
 */
static void notrace trace_save_gd(void)
{
	trace_gd = gd;
}

/**
 * trace_swap_gd() - swap between U-Boot and application gd register value
 *
 * An UEFI application may change the value of the register that gd lives in.
 * But some of our functions like get_ticks() access this register. So we
 * have to set the gd register to the U-Boot value when entering a trace
 * point and set it back to the application value when exiting the trace point.
 */
static void notrace trace_swap_gd(void)
{
	volatile gd_t *temp_gd = trace_gd;

	trace_gd = gd;
	set_gd(temp_gd);
}

#else

static void notrace trace_save_gd(void)
{
}

static void notrace trace_swap_gd(void)
{
}

#endif

static void notrace add_ftrace(void *func_ptr, void *caller, ulong flags)
{
	if (hdr->depth > hdr->depth_limit) {
		hdr->ftrace_too_deep_count++;
		return;
	}
	if (hdr->ftrace_count < hdr->ftrace_size) {
		struct trace_call *rec = &hdr->ftrace[hdr->ftrace_count];

		rec->func = func_ptr_to_num(func_ptr);
		rec->caller = func_ptr_to_num(caller);
		rec->flags = flags | (timer_get_us() & FUNCF_TIMESTAMP_MASK);
	}
	hdr->ftrace_count++;
}

/**
 * __cyg_profile_func_enter() - record function entry
 *
 * We add to our tally for this function and add to the list of called
 * functions.
 *
 * @func_ptr:	pointer to function being entered
 * @caller:	pointer to function which called this function
 */
void notrace __cyg_profile_func_enter(void *func_ptr, void *caller)
{
	if (trace_enabled) {
		int func;

		if (hdr->trace_locked) {
			trace_enabled = 0;
			puts("trace: recursion detected, disabling\n");
			hdr->trace_locked = false;
			return;
		}

		hdr->trace_locked = true;
		trace_swap_gd();
		add_ftrace(func_ptr, caller, FUNCF_ENTRY);
		func = func_ptr_to_num(func_ptr);
		if (func < hdr->func_count) {
			hdr->call_accum[func]++;
			hdr->call_count++;
		} else {
			hdr->untracked_count++;
		}
		hdr->depth++;
		if (hdr->depth > hdr->max_depth)
			hdr->max_depth = hdr->depth;
		trace_swap_gd();
		hdr->trace_locked = false;
	}
}

/**
 * __cyg_profile_func_exit() - record function exit
 *
 * @func_ptr:	pointer to function being entered
 * @caller:	pointer to function which called this function
 */
void notrace __cyg_profile_func_exit(void *func_ptr, void *caller)
{
	if (trace_enabled) {
		trace_swap_gd();
		hdr->depth--;
		add_ftrace(func_ptr, caller, FUNCF_EXIT);
		if (hdr->depth < hdr->min_depth)
			hdr->min_depth = hdr->depth;
		trace_swap_gd();
	}
}

/**
 * trace_list_functions() - produce a list of called functions
 *
 * The information is written into the supplied buffer - a header followed
 * by a list of function records.
 *
 * @buff:	buffer to place list into
 * @buff_size:	size of buffer
 * @needed:	returns size of buffer needed, which may be
 *		greater than buff_size if we ran out of space.
 * Return:	0 if ok, -ENOSPC if space was exhausted
 */
int trace_list_functions(void *buff, size_t buff_size, size_t *needed)
{
	struct trace_output_hdr *output_hdr = NULL;
	void *end, *ptr = buff;
	size_t func;
	size_t upto;

	end = buff ? buff + buff_size : NULL;

	/* Place some header information */
	if (ptr + sizeof(struct trace_output_hdr) < end)
		output_hdr = ptr;
	ptr += sizeof(struct trace_output_hdr);

	/* Add information about each function */
	for (func = upto = 0; func < hdr->func_count; func++) {
		size_t calls = hdr->call_accum[func];

		if (!calls)
			continue;

		if (ptr + sizeof(struct trace_output_func) < end) {
			struct trace_output_func *stats = ptr;

			stats->offset = func * FUNC_SITE_SIZE;
			stats->call_count = calls;
			upto++;
		}
		ptr += sizeof(struct trace_output_func);
	}

	/* Update the header */
	if (output_hdr) {
		output_hdr->rec_count = upto;
		output_hdr->type = TRACE_CHUNK_FUNCS;
	}

	/* Work out how must of the buffer we used */
	*needed = ptr - buff;
	if (ptr > end)
		return -ENOSPC;

	return 0;
}

/**
 * trace_list_functions() - produce a list of function calls
 *
 * The information is written into the supplied buffer - a header followed
 * by a list of function records.
 *
 * @buff:	buffer to place list into
 * @buff_size:	size of buffer
 * @needed:	returns size of buffer needed, which may be
 *		greater than buff_size if we ran out of space.
 * Return:	0 if ok, -ENOSPC if space was exhausted
 */
int trace_list_calls(void *buff, size_t buff_size, size_t *needed)
{
	struct trace_output_hdr *output_hdr = NULL;
	void *end, *ptr = buff;
	size_t rec, upto;
	size_t count;

	end = buff ? buff + buff_size : NULL;

	/* Place some header information */
	if (ptr + sizeof(struct trace_output_hdr) < end)
		output_hdr = ptr;
	ptr += sizeof(struct trace_output_hdr);

	/* Add information about each call */
	count = hdr->ftrace_count;
	if (count > hdr->ftrace_size)
		count = hdr->ftrace_size;
	for (rec = upto = 0; rec < count; rec++) {
		if (ptr + sizeof(struct trace_call) < end) {
			struct trace_call *call = &hdr->ftrace[rec];
			struct trace_call *out = ptr;

			out->func = call->func * FUNC_SITE_SIZE;
			out->caller = call->caller * FUNC_SITE_SIZE;
			out->flags = call->flags;
			upto++;
		}
		ptr += sizeof(struct trace_call);
	}

	/* Update the header */
	if (output_hdr) {
		memset(output_hdr, '\0', sizeof(*output_hdr));
		output_hdr->rec_count = upto;
		output_hdr->type = TRACE_CHUNK_CALLS;
		output_hdr->version = TRACE_VERSION;
		output_hdr->text_base = CONFIG_TEXT_BASE;
	}

	/* Work out how must of the buffer we used */
	*needed = ptr - buff;
	if (ptr > end)
		return -ENOSPC;

	return 0;
}

/**
 * trace_print_stats() - print basic information about tracing
 */
void trace_print_stats(void)
{
	ulong count;

#ifndef FTRACE
	puts("Warning: make U-Boot with FTRACE to enable function instrumenting.\n");
	puts("You will likely get zeroed data here\n");
#endif
	if (!trace_inited) {
		printf("Trace is disabled\n");
		return;
	}
	print_grouped_ull(hdr->func_count, 10);
	puts(" function sites\n");
	print_grouped_ull(hdr->call_count, 10);
	puts(" function calls\n");
	print_grouped_ull(hdr->untracked_count, 10);
	puts(" untracked function calls\n");
	count = min(hdr->ftrace_count, hdr->ftrace_size);
	print_grouped_ull(count, 10);
	puts(" traced function calls");
	if (hdr->ftrace_count > hdr->ftrace_size) {
		printf(" (%lu dropped due to overflow)",
		       hdr->ftrace_count - hdr->ftrace_size);
	}

	/* Add in minimum depth since the trace did not start at top level */
	printf("\n%15d maximum observed call depth\n",
	       hdr->max_depth - hdr->min_depth);
	printf("%15d call depth limit\n", hdr->depth_limit);
	print_grouped_ull(hdr->ftrace_too_deep_count, 10);
	puts(" calls not traced due to depth\n");
	print_grouped_ull(hdr->ftrace_size, 10);
	puts(" max function calls\n");
	printf("\ntrace buffer %lx call records %lx\n",
	       (ulong)map_to_sysmem(hdr), (ulong)map_to_sysmem(hdr->ftrace));
}

void notrace trace_set_enabled(int enabled)
{
	trace_enabled = enabled != 0;
}

static int get_func_count(void)
{
	/* Detect no support for mon_len since this means tracing cannot work */
	if (IS_ENABLED(CONFIG_SANDBOX) && !gd->mon_len) {
		puts("Tracing is not supported on this board\n");
		return -ENOTSUPP;
	}

	return gd->mon_len / FUNC_SITE_SIZE;
}

/**
 * trace_init() - initialize the tracing system and enable it
 *
 * @buff:	Pointer to trace buffer
 * @buff_size:	Size of trace buffer
 * Return:	0 if ok
 */
int notrace trace_init(void *buff, size_t buff_size)
{
	int func_count = get_func_count();
	size_t needed;
	int was_disabled = !trace_enabled;

	if (func_count < 0)
		return func_count;
	trace_save_gd();

	if (!was_disabled) {
#ifdef CONFIG_TRACE_EARLY
		ulong used, count;
		char *end;

		/*
		 * Copy over the early trace data if we have it. Disable
		 * tracing while we are doing this.
		 */
		trace_enabled = 0;
		hdr = map_sysmem(CONFIG_TRACE_EARLY_ADDR,
				 CONFIG_TRACE_EARLY_SIZE);
		count = min(hdr->ftrace_count, hdr->ftrace_size);
		end = (char *)&hdr->ftrace[count];
		used = end - (char *)hdr;
		printf("trace: copying %08lx bytes of early data from %x to %08lx\n",
		       used, CONFIG_TRACE_EARLY_ADDR,
		       (ulong)map_to_sysmem(buff));
		printf("%lu traced function calls", count);
		if (hdr->ftrace_count > hdr->ftrace_size) {
			printf(" (%lu dropped due to overflow)",
			       hdr->ftrace_count - hdr->ftrace_size);
			hdr->ftrace_count = hdr->ftrace_size;
		}
		puts("\n");
		memcpy(buff, hdr, used);
#else
		puts("trace: already enabled\n");
		return -EALREADY;
#endif
	}
	hdr = (struct trace_hdr *)buff;
	needed = sizeof(*hdr) + func_count * sizeof(uintptr_t);
	if (needed > buff_size) {
		printf("trace: buffer size %zx bytes: at least %zx needed\n",
		       buff_size, needed);
		return -ENOSPC;
	}

	if (was_disabled) {
		memset(hdr, '\0', needed);
		hdr->min_depth = INT_MAX;
	}
	hdr->func_count = func_count;
	hdr->call_accum = (uintptr_t *)(hdr + 1);

	/* Use any remaining space for the timed function trace */
	hdr->ftrace = (struct trace_call *)(buff + needed);
	hdr->ftrace_size = (buff_size - needed) / sizeof(*hdr->ftrace);
	hdr->depth_limit = CONFIG_TRACE_CALL_DEPTH_LIMIT;

	puts("trace: enabled\n");
	trace_enabled = 1;
	trace_inited = 1;

	return 0;
}

#ifdef CONFIG_TRACE_EARLY
/**
 * trace_early_init() - initialize the tracing system for early tracing
 *
 * Return:	0 if ok, -ENOSPC if not enough memory is available
 */
int notrace trace_early_init(void)
{
	int func_count = get_func_count();
	size_t buff_size = CONFIG_TRACE_EARLY_SIZE;
	size_t needed;

	if (func_count < 0)
		return func_count;
	/* We can ignore additional calls to this function */
	if (trace_enabled)
		return 0;

	hdr = map_sysmem(CONFIG_TRACE_EARLY_ADDR, CONFIG_TRACE_EARLY_SIZE);
	needed = sizeof(*hdr) + func_count * sizeof(uintptr_t);
	if (needed > buff_size) {
		printf("trace: buffer size is %zx bytes, at least %zx needed\n",
		       buff_size, needed);
		return -ENOSPC;
	}

	memset(hdr, '\0', needed);
	hdr->call_accum = (uintptr_t *)(hdr + 1);
	hdr->func_count = func_count;
	hdr->min_depth = INT_MAX;

	/* Use any remaining space for the timed function trace */
	hdr->ftrace = (struct trace_call *)((char *)hdr + needed);
	hdr->ftrace_size = (buff_size - needed) / sizeof(*hdr->ftrace);
	hdr->depth_limit = CONFIG_TRACE_EARLY_CALL_DEPTH_LIMIT;
	printf("trace: early enable at %08x\n", CONFIG_TRACE_EARLY_ADDR);

	trace_enabled = 1;

	return 0;
}
#endif