1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (C) 2015, Wang Nan <wangnan0@huawei.com>
4 * Copyright (C) 2015, Huawei Inc.
5 */
6
7 #include <errno.h>
8 #include <limits.h>
9 #include <stdio.h>
10 #include <stdlib.h>
11 #include <linux/err.h>
12 #include "debug.h"
13 #include "llvm-utils.h"
14 #include "config.h"
15 #include "util.h"
16 #include <sys/wait.h>
17
18 #define CLANG_BPF_CMD_DEFAULT_TEMPLATE \
19 "$CLANG_EXEC -D__KERNEL__ -D__NR_CPUS__=$NR_CPUS "\
20 "-DLINUX_VERSION_CODE=$LINUX_VERSION_CODE " \
21 "$CLANG_OPTIONS $KERNEL_INC_OPTIONS " \
22 "-Wno-unused-value -Wno-pointer-sign " \
23 "-working-directory $WORKING_DIR " \
24 "-c \"$CLANG_SOURCE\" -target bpf -O2 -o -"
25
26 struct llvm_param llvm_param = {
27 .clang_path = "clang",
28 .clang_bpf_cmd_template = CLANG_BPF_CMD_DEFAULT_TEMPLATE,
29 .clang_opt = NULL,
30 .kbuild_dir = NULL,
31 .kbuild_opts = NULL,
32 .user_set_param = false,
33 };
34
perf_llvm_config(const char * var,const char * value)35 int perf_llvm_config(const char *var, const char *value)
36 {
37 if (!strstarts(var, "llvm."))
38 return 0;
39 var += sizeof("llvm.") - 1;
40
41 if (!strcmp(var, "clang-path"))
42 llvm_param.clang_path = strdup(value);
43 else if (!strcmp(var, "clang-bpf-cmd-template"))
44 llvm_param.clang_bpf_cmd_template = strdup(value);
45 else if (!strcmp(var, "clang-opt"))
46 llvm_param.clang_opt = strdup(value);
47 else if (!strcmp(var, "kbuild-dir"))
48 llvm_param.kbuild_dir = strdup(value);
49 else if (!strcmp(var, "kbuild-opts"))
50 llvm_param.kbuild_opts = strdup(value);
51 else if (!strcmp(var, "dump-obj"))
52 llvm_param.dump_obj = !!perf_config_bool(var, value);
53 else {
54 pr_debug("Invalid LLVM config option: %s\n", value);
55 return -1;
56 }
57 llvm_param.user_set_param = true;
58 return 0;
59 }
60
61 static int
search_program(const char * def,const char * name,char * output)62 search_program(const char *def, const char *name,
63 char *output)
64 {
65 char *env, *path, *tmp = NULL;
66 char buf[PATH_MAX];
67 int ret;
68
69 output[0] = '\0';
70 if (def && def[0] != '\0') {
71 if (def[0] == '/') {
72 if (access(def, F_OK) == 0) {
73 strlcpy(output, def, PATH_MAX);
74 return 0;
75 }
76 } else if (def[0] != '\0')
77 name = def;
78 }
79
80 env = getenv("PATH");
81 if (!env)
82 return -1;
83 env = strdup(env);
84 if (!env)
85 return -1;
86
87 ret = -ENOENT;
88 path = strtok_r(env, ":", &tmp);
89 while (path) {
90 scnprintf(buf, sizeof(buf), "%s/%s", path, name);
91 if (access(buf, F_OK) == 0) {
92 strlcpy(output, buf, PATH_MAX);
93 ret = 0;
94 break;
95 }
96 path = strtok_r(NULL, ":", &tmp);
97 }
98
99 free(env);
100 return ret;
101 }
102
103 #define READ_SIZE 4096
104 static int
read_from_pipe(const char * cmd,void ** p_buf,size_t * p_read_sz)105 read_from_pipe(const char *cmd, void **p_buf, size_t *p_read_sz)
106 {
107 int err = 0;
108 void *buf = NULL;
109 FILE *file = NULL;
110 size_t read_sz = 0, buf_sz = 0;
111 char serr[STRERR_BUFSIZE];
112
113 file = popen(cmd, "r");
114 if (!file) {
115 pr_err("ERROR: unable to popen cmd: %s\n",
116 str_error_r(errno, serr, sizeof(serr)));
117 return -EINVAL;
118 }
119
120 while (!feof(file) && !ferror(file)) {
121 /*
122 * Make buf_sz always have obe byte extra space so we
123 * can put '\0' there.
124 */
125 if (buf_sz - read_sz < READ_SIZE + 1) {
126 void *new_buf;
127
128 buf_sz = read_sz + READ_SIZE + 1;
129 new_buf = realloc(buf, buf_sz);
130
131 if (!new_buf) {
132 pr_err("ERROR: failed to realloc memory\n");
133 err = -ENOMEM;
134 goto errout;
135 }
136
137 buf = new_buf;
138 }
139 read_sz += fread(buf + read_sz, 1, READ_SIZE, file);
140 }
141
142 if (buf_sz - read_sz < 1) {
143 pr_err("ERROR: internal error\n");
144 err = -EINVAL;
145 goto errout;
146 }
147
148 if (ferror(file)) {
149 pr_err("ERROR: error occurred when reading from pipe: %s\n",
150 str_error_r(errno, serr, sizeof(serr)));
151 err = -EIO;
152 goto errout;
153 }
154
155 err = WEXITSTATUS(pclose(file));
156 file = NULL;
157 if (err) {
158 err = -EINVAL;
159 goto errout;
160 }
161
162 /*
163 * If buf is string, give it terminal '\0' to make our life
164 * easier. If buf is not string, that '\0' is out of space
165 * indicated by read_sz so caller won't even notice it.
166 */
167 ((char *)buf)[read_sz] = '\0';
168
169 if (!p_buf)
170 free(buf);
171 else
172 *p_buf = buf;
173
174 if (p_read_sz)
175 *p_read_sz = read_sz;
176 return 0;
177
178 errout:
179 if (file)
180 pclose(file);
181 free(buf);
182 if (p_buf)
183 *p_buf = NULL;
184 if (p_read_sz)
185 *p_read_sz = 0;
186 return err;
187 }
188
189 static inline void
force_set_env(const char * var,const char * value)190 force_set_env(const char *var, const char *value)
191 {
192 if (value) {
193 setenv(var, value, 1);
194 pr_debug("set env: %s=%s\n", var, value);
195 } else {
196 unsetenv(var);
197 pr_debug("unset env: %s\n", var);
198 }
199 }
200
201 static void
version_notice(void)202 version_notice(void)
203 {
204 pr_err(
205 " \tLLVM 3.7 or newer is required. Which can be found from http://llvm.org\n"
206 " \tYou may want to try git trunk:\n"
207 " \t\tgit clone http://llvm.org/git/llvm.git\n"
208 " \t\t and\n"
209 " \t\tgit clone http://llvm.org/git/clang.git\n\n"
210 " \tOr fetch the latest clang/llvm 3.7 from pre-built llvm packages for\n"
211 " \tdebian/ubuntu:\n"
212 " \t\thttp://llvm.org/apt\n\n"
213 " \tIf you are using old version of clang, change 'clang-bpf-cmd-template'\n"
214 " \toption in [llvm] section of ~/.perfconfig to:\n\n"
215 " \t \"$CLANG_EXEC $CLANG_OPTIONS $KERNEL_INC_OPTIONS \\\n"
216 " \t -working-directory $WORKING_DIR -c $CLANG_SOURCE \\\n"
217 " \t -emit-llvm -o - | /path/to/llc -march=bpf -filetype=obj -o -\"\n"
218 " \t(Replace /path/to/llc with path to your llc)\n\n"
219 );
220 }
221
detect_kbuild_dir(char ** kbuild_dir)222 static int detect_kbuild_dir(char **kbuild_dir)
223 {
224 const char *test_dir = llvm_param.kbuild_dir;
225 const char *prefix_dir = "";
226 const char *suffix_dir = "";
227
228 /* _UTSNAME_LENGTH is 65 */
229 char release[128];
230
231 char *autoconf_path;
232
233 int err;
234
235 if (!test_dir) {
236 err = fetch_kernel_version(NULL, release,
237 sizeof(release));
238 if (err)
239 return -EINVAL;
240
241 test_dir = release;
242 prefix_dir = "/lib/modules/";
243 suffix_dir = "/build";
244 }
245
246 err = asprintf(&autoconf_path, "%s%s%s/include/generated/autoconf.h",
247 prefix_dir, test_dir, suffix_dir);
248 if (err < 0)
249 return -ENOMEM;
250
251 if (access(autoconf_path, R_OK) == 0) {
252 free(autoconf_path);
253
254 err = asprintf(kbuild_dir, "%s%s%s", prefix_dir, test_dir,
255 suffix_dir);
256 if (err < 0)
257 return -ENOMEM;
258 return 0;
259 }
260 free(autoconf_path);
261 return -ENOENT;
262 }
263
264 static const char *kinc_fetch_script =
265 "#!/usr/bin/env sh\n"
266 "if ! test -d \"$KBUILD_DIR\"\n"
267 "then\n"
268 " exit 1\n"
269 "fi\n"
270 "if ! test -f \"$KBUILD_DIR/include/generated/autoconf.h\"\n"
271 "then\n"
272 " exit 1\n"
273 "fi\n"
274 "TMPDIR=`mktemp -d`\n"
275 "if test -z \"$TMPDIR\"\n"
276 "then\n"
277 " exit 1\n"
278 "fi\n"
279 "cat << EOF > $TMPDIR/Makefile\n"
280 "obj-y := dummy.o\n"
281 "\\$(obj)/%.o: \\$(src)/%.c\n"
282 "\t@echo -n \"\\$(NOSTDINC_FLAGS) \\$(LINUXINCLUDE) \\$(EXTRA_CFLAGS)\"\n"
283 "EOF\n"
284 "touch $TMPDIR/dummy.c\n"
285 "make -s -C $KBUILD_DIR M=$TMPDIR $KBUILD_OPTS dummy.o 2>/dev/null\n"
286 "RET=$?\n"
287 "rm -rf $TMPDIR\n"
288 "exit $RET\n";
289
llvm__get_kbuild_opts(char ** kbuild_dir,char ** kbuild_include_opts)290 void llvm__get_kbuild_opts(char **kbuild_dir, char **kbuild_include_opts)
291 {
292 static char *saved_kbuild_dir;
293 static char *saved_kbuild_include_opts;
294 int err;
295
296 if (!kbuild_dir || !kbuild_include_opts)
297 return;
298
299 *kbuild_dir = NULL;
300 *kbuild_include_opts = NULL;
301
302 if (saved_kbuild_dir && saved_kbuild_include_opts &&
303 !IS_ERR(saved_kbuild_dir) && !IS_ERR(saved_kbuild_include_opts)) {
304 *kbuild_dir = strdup(saved_kbuild_dir);
305 *kbuild_include_opts = strdup(saved_kbuild_include_opts);
306
307 if (*kbuild_dir && *kbuild_include_opts)
308 return;
309
310 zfree(kbuild_dir);
311 zfree(kbuild_include_opts);
312 /*
313 * Don't fall through: it may breaks saved_kbuild_dir and
314 * saved_kbuild_include_opts if detect them again when
315 * memory is low.
316 */
317 return;
318 }
319
320 if (llvm_param.kbuild_dir && !llvm_param.kbuild_dir[0]) {
321 pr_debug("[llvm.kbuild-dir] is set to \"\" deliberately.\n");
322 pr_debug("Skip kbuild options detection.\n");
323 goto errout;
324 }
325
326 err = detect_kbuild_dir(kbuild_dir);
327 if (err) {
328 pr_warning(
329 "WARNING:\tunable to get correct kernel building directory.\n"
330 "Hint:\tSet correct kbuild directory using 'kbuild-dir' option in [llvm]\n"
331 " \tsection of ~/.perfconfig or set it to \"\" to suppress kbuild\n"
332 " \tdetection.\n\n");
333 goto errout;
334 }
335
336 pr_debug("Kernel build dir is set to %s\n", *kbuild_dir);
337 force_set_env("KBUILD_DIR", *kbuild_dir);
338 force_set_env("KBUILD_OPTS", llvm_param.kbuild_opts);
339 err = read_from_pipe(kinc_fetch_script,
340 (void **)kbuild_include_opts,
341 NULL);
342 if (err) {
343 pr_warning(
344 "WARNING:\tunable to get kernel include directories from '%s'\n"
345 "Hint:\tTry set clang include options using 'clang-bpf-cmd-template'\n"
346 " \toption in [llvm] section of ~/.perfconfig and set 'kbuild-dir'\n"
347 " \toption in [llvm] to \"\" to suppress this detection.\n\n",
348 *kbuild_dir);
349
350 free(*kbuild_dir);
351 *kbuild_dir = NULL;
352 goto errout;
353 }
354
355 pr_debug("include option is set to %s\n", *kbuild_include_opts);
356
357 saved_kbuild_dir = strdup(*kbuild_dir);
358 saved_kbuild_include_opts = strdup(*kbuild_include_opts);
359
360 if (!saved_kbuild_dir || !saved_kbuild_include_opts) {
361 zfree(&saved_kbuild_dir);
362 zfree(&saved_kbuild_include_opts);
363 }
364 return;
365 errout:
366 saved_kbuild_dir = ERR_PTR(-EINVAL);
367 saved_kbuild_include_opts = ERR_PTR(-EINVAL);
368 }
369
llvm__get_nr_cpus(void)370 int llvm__get_nr_cpus(void)
371 {
372 static int nr_cpus_avail = 0;
373 char serr[STRERR_BUFSIZE];
374
375 if (nr_cpus_avail > 0)
376 return nr_cpus_avail;
377
378 nr_cpus_avail = sysconf(_SC_NPROCESSORS_CONF);
379 if (nr_cpus_avail <= 0) {
380 pr_err(
381 "WARNING:\tunable to get available CPUs in this system: %s\n"
382 " \tUse 128 instead.\n", str_error_r(errno, serr, sizeof(serr)));
383 nr_cpus_avail = 128;
384 }
385 return nr_cpus_avail;
386 }
387
llvm__dump_obj(const char * path,void * obj_buf,size_t size)388 void llvm__dump_obj(const char *path, void *obj_buf, size_t size)
389 {
390 char *obj_path = strdup(path);
391 FILE *fp;
392 char *p;
393
394 if (!obj_path) {
395 pr_warning("WARNING: Not enough memory, skip object dumping\n");
396 return;
397 }
398
399 p = strrchr(obj_path, '.');
400 if (!p || (strcmp(p, ".c") != 0)) {
401 pr_warning("WARNING: invalid llvm source path: '%s', skip object dumping\n",
402 obj_path);
403 goto out;
404 }
405
406 p[1] = 'o';
407 fp = fopen(obj_path, "wb");
408 if (!fp) {
409 pr_warning("WARNING: failed to open '%s': %s, skip object dumping\n",
410 obj_path, strerror(errno));
411 goto out;
412 }
413
414 pr_info("LLVM: dumping %s\n", obj_path);
415 if (fwrite(obj_buf, size, 1, fp) != 1)
416 pr_warning("WARNING: failed to write to file '%s': %s, skip object dumping\n",
417 obj_path, strerror(errno));
418 fclose(fp);
419 out:
420 free(obj_path);
421 }
422
llvm__compile_bpf(const char * path,void ** p_obj_buf,size_t * p_obj_buf_sz)423 int llvm__compile_bpf(const char *path, void **p_obj_buf,
424 size_t *p_obj_buf_sz)
425 {
426 size_t obj_buf_sz;
427 void *obj_buf = NULL;
428 int err, nr_cpus_avail;
429 unsigned int kernel_version;
430 char linux_version_code_str[64];
431 const char *clang_opt = llvm_param.clang_opt;
432 char clang_path[PATH_MAX], abspath[PATH_MAX], nr_cpus_avail_str[64];
433 char serr[STRERR_BUFSIZE];
434 char *kbuild_dir = NULL, *kbuild_include_opts = NULL;
435 const char *template = llvm_param.clang_bpf_cmd_template;
436
437 if (path[0] != '-' && realpath(path, abspath) == NULL) {
438 err = errno;
439 pr_err("ERROR: problems with path %s: %s\n",
440 path, str_error_r(err, serr, sizeof(serr)));
441 return -err;
442 }
443
444 if (!template)
445 template = CLANG_BPF_CMD_DEFAULT_TEMPLATE;
446
447 err = search_program(llvm_param.clang_path,
448 "clang", clang_path);
449 if (err) {
450 pr_err(
451 "ERROR:\tunable to find clang.\n"
452 "Hint:\tTry to install latest clang/llvm to support BPF. Check your $PATH\n"
453 " \tand 'clang-path' option in [llvm] section of ~/.perfconfig.\n");
454 version_notice();
455 return -ENOENT;
456 }
457
458 /*
459 * This is an optional work. Even it fail we can continue our
460 * work. Needn't to check error return.
461 */
462 llvm__get_kbuild_opts(&kbuild_dir, &kbuild_include_opts);
463
464 nr_cpus_avail = llvm__get_nr_cpus();
465 snprintf(nr_cpus_avail_str, sizeof(nr_cpus_avail_str), "%d",
466 nr_cpus_avail);
467
468 if (fetch_kernel_version(&kernel_version, NULL, 0))
469 kernel_version = 0;
470
471 snprintf(linux_version_code_str, sizeof(linux_version_code_str),
472 "0x%x", kernel_version);
473
474 force_set_env("NR_CPUS", nr_cpus_avail_str);
475 force_set_env("LINUX_VERSION_CODE", linux_version_code_str);
476 force_set_env("CLANG_EXEC", clang_path);
477 force_set_env("CLANG_OPTIONS", clang_opt);
478 force_set_env("KERNEL_INC_OPTIONS", kbuild_include_opts);
479 force_set_env("WORKING_DIR", kbuild_dir ? : ".");
480
481 /*
482 * Since we may reset clang's working dir, path of source file
483 * should be transferred into absolute path, except we want
484 * stdin to be source file (testing).
485 */
486 force_set_env("CLANG_SOURCE",
487 (path[0] == '-') ? path : abspath);
488
489 pr_debug("llvm compiling command template: %s\n", template);
490 err = read_from_pipe(template, &obj_buf, &obj_buf_sz);
491 if (err) {
492 pr_err("ERROR:\tunable to compile %s\n", path);
493 pr_err("Hint:\tCheck error message shown above.\n");
494 pr_err("Hint:\tYou can also pre-compile it into .o using:\n");
495 pr_err(" \t\tclang -target bpf -O2 -c %s\n", path);
496 pr_err(" \twith proper -I and -D options.\n");
497 goto errout;
498 }
499
500 free(kbuild_dir);
501 free(kbuild_include_opts);
502
503 if (!p_obj_buf)
504 free(obj_buf);
505 else
506 *p_obj_buf = obj_buf;
507
508 if (p_obj_buf_sz)
509 *p_obj_buf_sz = obj_buf_sz;
510 return 0;
511 errout:
512 free(kbuild_dir);
513 free(kbuild_include_opts);
514 free(obj_buf);
515 if (p_obj_buf)
516 *p_obj_buf = NULL;
517 if (p_obj_buf_sz)
518 *p_obj_buf_sz = 0;
519 return err;
520 }
521
llvm__search_clang(void)522 int llvm__search_clang(void)
523 {
524 char clang_path[PATH_MAX];
525
526 return search_program(llvm_param.clang_path, "clang", clang_path);
527 }
528