1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * Copyright (C) 2019 Google, Inc. |
4 | * modified from kernel/gcov/gcc_4_7.c |
5 | * |
6 | * This software is licensed under the terms of the GNU General Public |
7 | * License version 2, as published by the Free Software Foundation, and |
8 | * may be copied, distributed, and modified under those terms. |
9 | * |
10 | * This program is distributed in the hope that it will be useful, |
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
13 | * GNU General Public License for more details. |
14 | * |
15 | * |
16 | * LLVM uses profiling data that's deliberately similar to GCC, but has a |
17 | * very different way of exporting that data. LLVM calls llvm_gcov_init() once |
18 | * per module, and provides a couple of callbacks that we can use to ask for |
19 | * more data. |
20 | * |
21 | * We care about the "writeout" callback, which in turn calls back into |
22 | * compiler-rt/this module to dump all the gathered coverage data to disk: |
23 | * |
24 | * llvm_gcda_start_file() |
25 | * llvm_gcda_emit_function() |
26 | * llvm_gcda_emit_arcs() |
27 | * llvm_gcda_emit_function() |
28 | * llvm_gcda_emit_arcs() |
29 | * [... repeats for each function ...] |
30 | * llvm_gcda_summary_info() |
31 | * llvm_gcda_end_file() |
32 | * |
33 | * This design is much more stateless and unstructured than gcc's, and is |
34 | * intended to run at process exit. This forces us to keep some local state |
35 | * about which module we're dealing with at the moment. On the other hand, it |
36 | * also means we don't depend as much on how LLVM represents profiling data |
37 | * internally. |
38 | * |
39 | * See LLVM's lib/Transforms/Instrumentation/GCOVProfiling.cpp for more |
40 | * details on how this works, particularly GCOVProfiler::emitProfileArcs(), |
41 | * GCOVProfiler::insertCounterWriteout(), and |
42 | * GCOVProfiler::insertFlush(). |
43 | */ |
44 | |
45 | #define pr_fmt(fmt) "gcov: " fmt |
46 | |
47 | #include <linux/kernel.h> |
48 | #include <linux/list.h> |
49 | #include <linux/printk.h> |
50 | #include <linux/ratelimit.h> |
51 | #include <linux/slab.h> |
52 | #include <linux/mm.h> |
53 | #include "gcov.h" |
54 | |
55 | typedef void (*llvm_gcov_callback)(void); |
56 | |
57 | struct gcov_info { |
58 | struct list_head head; |
59 | |
60 | const char *filename; |
61 | unsigned int version; |
62 | u32 checksum; |
63 | |
64 | struct list_head functions; |
65 | }; |
66 | |
67 | struct gcov_fn_info { |
68 | struct list_head head; |
69 | |
70 | u32 ident; |
71 | u32 checksum; |
72 | u32 cfg_checksum; |
73 | |
74 | u32 num_counters; |
75 | u64 *counters; |
76 | }; |
77 | |
78 | static struct gcov_info *current_info; |
79 | |
80 | static LIST_HEAD(clang_gcov_list); |
81 | |
82 | void llvm_gcov_init(llvm_gcov_callback writeout, llvm_gcov_callback flush) |
83 | { |
84 | struct gcov_info *info = kzalloc(size: sizeof(*info), GFP_KERNEL); |
85 | |
86 | if (!info) |
87 | return; |
88 | |
89 | INIT_LIST_HEAD(list: &info->head); |
90 | INIT_LIST_HEAD(list: &info->functions); |
91 | |
92 | mutex_lock(&gcov_lock); |
93 | |
94 | list_add_tail(new: &info->head, head: &clang_gcov_list); |
95 | current_info = info; |
96 | writeout(); |
97 | current_info = NULL; |
98 | if (gcov_events_enabled) |
99 | gcov_event(action: GCOV_ADD, info); |
100 | |
101 | mutex_unlock(lock: &gcov_lock); |
102 | } |
103 | EXPORT_SYMBOL(llvm_gcov_init); |
104 | |
105 | void llvm_gcda_start_file(const char *orig_filename, u32 version, u32 checksum) |
106 | { |
107 | current_info->filename = orig_filename; |
108 | current_info->version = version; |
109 | current_info->checksum = checksum; |
110 | } |
111 | EXPORT_SYMBOL(llvm_gcda_start_file); |
112 | |
113 | void llvm_gcda_emit_function(u32 ident, u32 func_checksum, u32 cfg_checksum) |
114 | { |
115 | struct gcov_fn_info *info = kzalloc(size: sizeof(*info), GFP_KERNEL); |
116 | |
117 | if (!info) |
118 | return; |
119 | |
120 | INIT_LIST_HEAD(list: &info->head); |
121 | info->ident = ident; |
122 | info->checksum = func_checksum; |
123 | info->cfg_checksum = cfg_checksum; |
124 | list_add_tail(new: &info->head, head: ¤t_info->functions); |
125 | } |
126 | EXPORT_SYMBOL(llvm_gcda_emit_function); |
127 | |
128 | void llvm_gcda_emit_arcs(u32 num_counters, u64 *counters) |
129 | { |
130 | struct gcov_fn_info *info = list_last_entry(¤t_info->functions, |
131 | struct gcov_fn_info, head); |
132 | |
133 | info->num_counters = num_counters; |
134 | info->counters = counters; |
135 | } |
136 | EXPORT_SYMBOL(llvm_gcda_emit_arcs); |
137 | |
138 | void llvm_gcda_summary_info(void) |
139 | { |
140 | } |
141 | EXPORT_SYMBOL(llvm_gcda_summary_info); |
142 | |
143 | void llvm_gcda_end_file(void) |
144 | { |
145 | } |
146 | EXPORT_SYMBOL(llvm_gcda_end_file); |
147 | |
148 | /** |
149 | * gcov_info_filename - return info filename |
150 | * @info: profiling data set |
151 | */ |
152 | const char *gcov_info_filename(struct gcov_info *info) |
153 | { |
154 | return info->filename; |
155 | } |
156 | |
157 | /** |
158 | * gcov_info_version - return info version |
159 | * @info: profiling data set |
160 | */ |
161 | unsigned int gcov_info_version(struct gcov_info *info) |
162 | { |
163 | return info->version; |
164 | } |
165 | |
166 | /** |
167 | * gcov_info_next - return next profiling data set |
168 | * @info: profiling data set |
169 | * |
170 | * Returns next gcov_info following @info or first gcov_info in the chain if |
171 | * @info is %NULL. |
172 | */ |
173 | struct gcov_info *gcov_info_next(struct gcov_info *info) |
174 | { |
175 | if (!info) |
176 | return list_first_entry_or_null(&clang_gcov_list, |
177 | struct gcov_info, head); |
178 | if (list_is_last(list: &info->head, head: &clang_gcov_list)) |
179 | return NULL; |
180 | return list_next_entry(info, head); |
181 | } |
182 | |
183 | /** |
184 | * gcov_info_link - link/add profiling data set to the list |
185 | * @info: profiling data set |
186 | */ |
187 | void gcov_info_link(struct gcov_info *info) |
188 | { |
189 | list_add_tail(new: &info->head, head: &clang_gcov_list); |
190 | } |
191 | |
192 | /** |
193 | * gcov_info_unlink - unlink/remove profiling data set from the list |
194 | * @prev: previous profiling data set |
195 | * @info: profiling data set |
196 | */ |
197 | void gcov_info_unlink(struct gcov_info *prev, struct gcov_info *info) |
198 | { |
199 | /* Generic code unlinks while iterating. */ |
200 | __list_del_entry(entry: &info->head); |
201 | } |
202 | |
203 | /** |
204 | * gcov_info_within_module - check if a profiling data set belongs to a module |
205 | * @info: profiling data set |
206 | * @mod: module |
207 | * |
208 | * Returns true if profiling data belongs module, false otherwise. |
209 | */ |
210 | bool gcov_info_within_module(struct gcov_info *info, struct module *mod) |
211 | { |
212 | return within_module(addr: (unsigned long)info->filename, mod); |
213 | } |
214 | |
215 | /* Symbolic links to be created for each profiling data file. */ |
216 | const struct gcov_link gcov_link[] = { |
217 | { OBJ_TREE, "gcno" }, /* Link to .gcno file in $(objtree). */ |
218 | { 0, NULL}, |
219 | }; |
220 | |
221 | /** |
222 | * gcov_info_reset - reset profiling data to zero |
223 | * @info: profiling data set |
224 | */ |
225 | void gcov_info_reset(struct gcov_info *info) |
226 | { |
227 | struct gcov_fn_info *fn; |
228 | |
229 | list_for_each_entry(fn, &info->functions, head) |
230 | memset(fn->counters, 0, |
231 | sizeof(fn->counters[0]) * fn->num_counters); |
232 | } |
233 | |
234 | /** |
235 | * gcov_info_is_compatible - check if profiling data can be added |
236 | * @info1: first profiling data set |
237 | * @info2: second profiling data set |
238 | * |
239 | * Returns non-zero if profiling data can be added, zero otherwise. |
240 | */ |
241 | int gcov_info_is_compatible(struct gcov_info *info1, struct gcov_info *info2) |
242 | { |
243 | struct gcov_fn_info *fn_ptr1 = list_first_entry_or_null( |
244 | &info1->functions, struct gcov_fn_info, head); |
245 | struct gcov_fn_info *fn_ptr2 = list_first_entry_or_null( |
246 | &info2->functions, struct gcov_fn_info, head); |
247 | |
248 | if (info1->checksum != info2->checksum) |
249 | return false; |
250 | if (!fn_ptr1) |
251 | return fn_ptr1 == fn_ptr2; |
252 | while (!list_is_last(list: &fn_ptr1->head, head: &info1->functions) && |
253 | !list_is_last(list: &fn_ptr2->head, head: &info2->functions)) { |
254 | if (fn_ptr1->checksum != fn_ptr2->checksum) |
255 | return false; |
256 | if (fn_ptr1->cfg_checksum != fn_ptr2->cfg_checksum) |
257 | return false; |
258 | fn_ptr1 = list_next_entry(fn_ptr1, head); |
259 | fn_ptr2 = list_next_entry(fn_ptr2, head); |
260 | } |
261 | return list_is_last(list: &fn_ptr1->head, head: &info1->functions) && |
262 | list_is_last(list: &fn_ptr2->head, head: &info2->functions); |
263 | } |
264 | |
265 | /** |
266 | * gcov_info_add - add up profiling data |
267 | * @dest: profiling data set to which data is added |
268 | * @source: profiling data set which is added |
269 | * |
270 | * Adds profiling counts of @source to @dest. |
271 | */ |
272 | void gcov_info_add(struct gcov_info *dst, struct gcov_info *src) |
273 | { |
274 | struct gcov_fn_info *dfn_ptr; |
275 | struct gcov_fn_info *sfn_ptr = list_first_entry_or_null(&src->functions, |
276 | struct gcov_fn_info, head); |
277 | |
278 | list_for_each_entry(dfn_ptr, &dst->functions, head) { |
279 | u32 i; |
280 | |
281 | for (i = 0; i < sfn_ptr->num_counters; i++) |
282 | dfn_ptr->counters[i] += sfn_ptr->counters[i]; |
283 | |
284 | sfn_ptr = list_next_entry(sfn_ptr, head); |
285 | } |
286 | } |
287 | |
288 | static struct gcov_fn_info *gcov_fn_info_dup(struct gcov_fn_info *fn) |
289 | { |
290 | size_t cv_size; /* counter values size */ |
291 | struct gcov_fn_info *fn_dup = kmemdup(p: fn, size: sizeof(*fn), |
292 | GFP_KERNEL); |
293 | if (!fn_dup) |
294 | return NULL; |
295 | INIT_LIST_HEAD(list: &fn_dup->head); |
296 | |
297 | cv_size = fn->num_counters * sizeof(fn->counters[0]); |
298 | fn_dup->counters = kvmalloc(size: cv_size, GFP_KERNEL); |
299 | if (!fn_dup->counters) { |
300 | kfree(objp: fn_dup); |
301 | return NULL; |
302 | } |
303 | |
304 | memcpy(fn_dup->counters, fn->counters, cv_size); |
305 | |
306 | return fn_dup; |
307 | } |
308 | |
309 | /** |
310 | * gcov_info_dup - duplicate profiling data set |
311 | * @info: profiling data set to duplicate |
312 | * |
313 | * Return newly allocated duplicate on success, %NULL on error. |
314 | */ |
315 | struct gcov_info *gcov_info_dup(struct gcov_info *info) |
316 | { |
317 | struct gcov_info *dup; |
318 | struct gcov_fn_info *fn; |
319 | |
320 | dup = kmemdup(p: info, size: sizeof(*dup), GFP_KERNEL); |
321 | if (!dup) |
322 | return NULL; |
323 | INIT_LIST_HEAD(list: &dup->head); |
324 | INIT_LIST_HEAD(list: &dup->functions); |
325 | dup->filename = kstrdup(s: info->filename, GFP_KERNEL); |
326 | if (!dup->filename) |
327 | goto err; |
328 | |
329 | list_for_each_entry(fn, &info->functions, head) { |
330 | struct gcov_fn_info *fn_dup = gcov_fn_info_dup(fn); |
331 | |
332 | if (!fn_dup) |
333 | goto err; |
334 | list_add_tail(new: &fn_dup->head, head: &dup->functions); |
335 | } |
336 | |
337 | return dup; |
338 | |
339 | err: |
340 | gcov_info_free(info: dup); |
341 | return NULL; |
342 | } |
343 | |
344 | /** |
345 | * gcov_info_free - release memory for profiling data set duplicate |
346 | * @info: profiling data set duplicate to free |
347 | */ |
348 | void gcov_info_free(struct gcov_info *info) |
349 | { |
350 | struct gcov_fn_info *fn, *tmp; |
351 | |
352 | list_for_each_entry_safe(fn, tmp, &info->functions, head) { |
353 | kvfree(addr: fn->counters); |
354 | list_del(entry: &fn->head); |
355 | kfree(objp: fn); |
356 | } |
357 | kfree(objp: info->filename); |
358 | kfree(objp: info); |
359 | } |
360 | |
361 | /** |
362 | * convert_to_gcda - convert profiling data set to gcda file format |
363 | * @buffer: the buffer to store file data or %NULL if no data should be stored |
364 | * @info: profiling data set to be converted |
365 | * |
366 | * Returns the number of bytes that were/would have been stored into the buffer. |
367 | */ |
368 | size_t convert_to_gcda(char *buffer, struct gcov_info *info) |
369 | { |
370 | struct gcov_fn_info *fi_ptr; |
371 | size_t pos = 0; |
372 | |
373 | /* File header. */ |
374 | pos += store_gcov_u32(buffer, off: pos, GCOV_DATA_MAGIC); |
375 | pos += store_gcov_u32(buffer, off: pos, v: info->version); |
376 | pos += store_gcov_u32(buffer, off: pos, v: info->checksum); |
377 | |
378 | list_for_each_entry(fi_ptr, &info->functions, head) { |
379 | u32 i; |
380 | |
381 | pos += store_gcov_u32(buffer, off: pos, GCOV_TAG_FUNCTION); |
382 | pos += store_gcov_u32(buffer, off: pos, v: 3); |
383 | pos += store_gcov_u32(buffer, off: pos, v: fi_ptr->ident); |
384 | pos += store_gcov_u32(buffer, off: pos, v: fi_ptr->checksum); |
385 | pos += store_gcov_u32(buffer, off: pos, v: fi_ptr->cfg_checksum); |
386 | pos += store_gcov_u32(buffer, off: pos, GCOV_TAG_COUNTER_BASE); |
387 | pos += store_gcov_u32(buffer, off: pos, v: fi_ptr->num_counters * 2); |
388 | for (i = 0; i < fi_ptr->num_counters; i++) |
389 | pos += store_gcov_u64(buffer, off: pos, v: fi_ptr->counters[i]); |
390 | } |
391 | |
392 | return pos; |
393 | } |
394 | |