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 #include <subcmd/exec-cmd.h>
18
19 #define CLANG_BPF_CMD_DEFAULT_TEMPLATE \
20 "$CLANG_EXEC -D__KERNEL__ -D__NR_CPUS__=$NR_CPUS "\
21 "-DLINUX_VERSION_CODE=$LINUX_VERSION_CODE " \
22 "$CLANG_OPTIONS $KERNEL_INC_OPTIONS $PERF_BPF_INC_OPTIONS " \
23 "-Wno-unused-value -Wno-pointer-sign " \
24 "-working-directory $WORKING_DIR " \
25 "-c \"$CLANG_SOURCE\" -target bpf $CLANG_EMIT_LLVM -O2 -o - $LLVM_OPTIONS_PIPE"
26
27 struct llvm_param llvm_param = {
28 .clang_path = "clang",
29 .llc_path = "llc",
30 .clang_bpf_cmd_template = CLANG_BPF_CMD_DEFAULT_TEMPLATE,
31 .clang_opt = NULL,
32 .opts = NULL,
33 .kbuild_dir = NULL,
34 .kbuild_opts = NULL,
35 .user_set_param = false,
36 };
37
perf_llvm_config(const char * var,const char * value)38 int perf_llvm_config(const char *var, const char *value)
39 {
40 if (!strstarts(var, "llvm."))
41 return 0;
42 var += sizeof("llvm.") - 1;
43
44 if (!strcmp(var, "clang-path"))
45 llvm_param.clang_path = strdup(value);
46 else if (!strcmp(var, "clang-bpf-cmd-template"))
47 llvm_param.clang_bpf_cmd_template = strdup(value);
48 else if (!strcmp(var, "clang-opt"))
49 llvm_param.clang_opt = strdup(value);
50 else if (!strcmp(var, "kbuild-dir"))
51 llvm_param.kbuild_dir = strdup(value);
52 else if (!strcmp(var, "kbuild-opts"))
53 llvm_param.kbuild_opts = strdup(value);
54 else if (!strcmp(var, "dump-obj"))
55 llvm_param.dump_obj = !!perf_config_bool(var, value);
56 else if (!strcmp(var, "opts"))
57 llvm_param.opts = strdup(value);
58 else {
59 pr_debug("Invalid LLVM config option: %s\n", value);
60 return -1;
61 }
62 llvm_param.user_set_param = true;
63 return 0;
64 }
65
66 static int
search_program(const char * def,const char * name,char * output)67 search_program(const char *def, const char *name,
68 char *output)
69 {
70 char *env, *path, *tmp = NULL;
71 char buf[PATH_MAX];
72 int ret;
73
74 output[0] = '\0';
75 if (def && def[0] != '\0') {
76 if (def[0] == '/') {
77 if (access(def, F_OK) == 0) {
78 strlcpy(output, def, PATH_MAX);
79 return 0;
80 }
81 } else if (def[0] != '\0')
82 name = def;
83 }
84
85 env = getenv("PATH");
86 if (!env)
87 return -1;
88 env = strdup(env);
89 if (!env)
90 return -1;
91
92 ret = -ENOENT;
93 path = strtok_r(env, ":", &tmp);
94 while (path) {
95 scnprintf(buf, sizeof(buf), "%s/%s", path, name);
96 if (access(buf, F_OK) == 0) {
97 strlcpy(output, buf, PATH_MAX);
98 ret = 0;
99 break;
100 }
101 path = strtok_r(NULL, ":", &tmp);
102 }
103
104 free(env);
105 return ret;
106 }
107
108 #define READ_SIZE 4096
109 static int
read_from_pipe(const char * cmd,void ** p_buf,size_t * p_read_sz)110 read_from_pipe(const char *cmd, void **p_buf, size_t *p_read_sz)
111 {
112 int err = 0;
113 void *buf = NULL;
114 FILE *file = NULL;
115 size_t read_sz = 0, buf_sz = 0;
116 char serr[STRERR_BUFSIZE];
117
118 file = popen(cmd, "r");
119 if (!file) {
120 pr_err("ERROR: unable to popen cmd: %s\n",
121 str_error_r(errno, serr, sizeof(serr)));
122 return -EINVAL;
123 }
124
125 while (!feof(file) && !ferror(file)) {
126 /*
127 * Make buf_sz always have obe byte extra space so we
128 * can put '\0' there.
129 */
130 if (buf_sz - read_sz < READ_SIZE + 1) {
131 void *new_buf;
132
133 buf_sz = read_sz + READ_SIZE + 1;
134 new_buf = realloc(buf, buf_sz);
135
136 if (!new_buf) {
137 pr_err("ERROR: failed to realloc memory\n");
138 err = -ENOMEM;
139 goto errout;
140 }
141
142 buf = new_buf;
143 }
144 read_sz += fread(buf + read_sz, 1, READ_SIZE, file);
145 }
146
147 if (buf_sz - read_sz < 1) {
148 pr_err("ERROR: internal error\n");
149 err = -EINVAL;
150 goto errout;
151 }
152
153 if (ferror(file)) {
154 pr_err("ERROR: error occurred when reading from pipe: %s\n",
155 str_error_r(errno, serr, sizeof(serr)));
156 err = -EIO;
157 goto errout;
158 }
159
160 err = WEXITSTATUS(pclose(file));
161 file = NULL;
162 if (err) {
163 err = -EINVAL;
164 goto errout;
165 }
166
167 /*
168 * If buf is string, give it terminal '\0' to make our life
169 * easier. If buf is not string, that '\0' is out of space
170 * indicated by read_sz so caller won't even notice it.
171 */
172 ((char *)buf)[read_sz] = '\0';
173
174 if (!p_buf)
175 free(buf);
176 else
177 *p_buf = buf;
178
179 if (p_read_sz)
180 *p_read_sz = read_sz;
181 return 0;
182
183 errout:
184 if (file)
185 pclose(file);
186 free(buf);
187 if (p_buf)
188 *p_buf = NULL;
189 if (p_read_sz)
190 *p_read_sz = 0;
191 return err;
192 }
193
194 static inline void
force_set_env(const char * var,const char * value)195 force_set_env(const char *var, const char *value)
196 {
197 if (value) {
198 setenv(var, value, 1);
199 pr_debug("set env: %s=%s\n", var, value);
200 } else {
201 unsetenv(var);
202 pr_debug("unset env: %s\n", var);
203 }
204 }
205
206 static void
version_notice(void)207 version_notice(void)
208 {
209 pr_err(
210 " \tLLVM 3.7 or newer is required. Which can be found from http://llvm.org\n"
211 " \tYou may want to try git trunk:\n"
212 " \t\tgit clone http://llvm.org/git/llvm.git\n"
213 " \t\t and\n"
214 " \t\tgit clone http://llvm.org/git/clang.git\n\n"
215 " \tOr fetch the latest clang/llvm 3.7 from pre-built llvm packages for\n"
216 " \tdebian/ubuntu:\n"
217 " \t\thttp://llvm.org/apt\n\n"
218 " \tIf you are using old version of clang, change 'clang-bpf-cmd-template'\n"
219 " \toption in [llvm] section of ~/.perfconfig to:\n\n"
220 " \t \"$CLANG_EXEC $CLANG_OPTIONS $KERNEL_INC_OPTIONS $PERF_BPF_INC_OPTIONS \\\n"
221 " \t -working-directory $WORKING_DIR -c $CLANG_SOURCE \\\n"
222 " \t -emit-llvm -o - | /path/to/llc -march=bpf -filetype=obj -o -\"\n"
223 " \t(Replace /path/to/llc with path to your llc)\n\n"
224 );
225 }
226
detect_kbuild_dir(char ** kbuild_dir)227 static int detect_kbuild_dir(char **kbuild_dir)
228 {
229 const char *test_dir = llvm_param.kbuild_dir;
230 const char *prefix_dir = "";
231 const char *suffix_dir = "";
232
233 char *autoconf_path;
234
235 int err;
236
237 if (!test_dir) {
238 /* _UTSNAME_LENGTH is 65 */
239 char release[128];
240
241 err = fetch_kernel_version(NULL, release,
242 sizeof(release));
243 if (err)
244 return -EINVAL;
245
246 test_dir = release;
247 prefix_dir = "/lib/modules/";
248 suffix_dir = "/build";
249 }
250
251 err = asprintf(&autoconf_path, "%s%s%s/include/generated/autoconf.h",
252 prefix_dir, test_dir, suffix_dir);
253 if (err < 0)
254 return -ENOMEM;
255
256 if (access(autoconf_path, R_OK) == 0) {
257 free(autoconf_path);
258
259 err = asprintf(kbuild_dir, "%s%s%s", prefix_dir, test_dir,
260 suffix_dir);
261 if (err < 0)
262 return -ENOMEM;
263 return 0;
264 }
265 free(autoconf_path);
266 return -ENOENT;
267 }
268
269 static const char *kinc_fetch_script =
270 "#!/usr/bin/env sh\n"
271 "if ! test -d \"$KBUILD_DIR\"\n"
272 "then\n"
273 " exit 1\n"
274 "fi\n"
275 "if ! test -f \"$KBUILD_DIR/include/generated/autoconf.h\"\n"
276 "then\n"
277 " exit 1\n"
278 "fi\n"
279 "TMPDIR=`mktemp -d`\n"
280 "if test -z \"$TMPDIR\"\n"
281 "then\n"
282 " exit 1\n"
283 "fi\n"
284 "cat << EOF > $TMPDIR/Makefile\n"
285 "obj-y := dummy.o\n"
286 "\\$(obj)/%.o: \\$(src)/%.c\n"
287 "\t@echo -n \"\\$(NOSTDINC_FLAGS) \\$(LINUXINCLUDE) \\$(EXTRA_CFLAGS)\"\n"
288 "EOF\n"
289 "touch $TMPDIR/dummy.c\n"
290 "make -s -C $KBUILD_DIR M=$TMPDIR $KBUILD_OPTS dummy.o 2>/dev/null\n"
291 "RET=$?\n"
292 "rm -rf $TMPDIR\n"
293 "exit $RET\n";
294
llvm__get_kbuild_opts(char ** kbuild_dir,char ** kbuild_include_opts)295 void llvm__get_kbuild_opts(char **kbuild_dir, char **kbuild_include_opts)
296 {
297 static char *saved_kbuild_dir;
298 static char *saved_kbuild_include_opts;
299 int err;
300
301 if (!kbuild_dir || !kbuild_include_opts)
302 return;
303
304 *kbuild_dir = NULL;
305 *kbuild_include_opts = NULL;
306
307 if (saved_kbuild_dir && saved_kbuild_include_opts &&
308 !IS_ERR(saved_kbuild_dir) && !IS_ERR(saved_kbuild_include_opts)) {
309 *kbuild_dir = strdup(saved_kbuild_dir);
310 *kbuild_include_opts = strdup(saved_kbuild_include_opts);
311
312 if (*kbuild_dir && *kbuild_include_opts)
313 return;
314
315 zfree(kbuild_dir);
316 zfree(kbuild_include_opts);
317 /*
318 * Don't fall through: it may breaks saved_kbuild_dir and
319 * saved_kbuild_include_opts if detect them again when
320 * memory is low.
321 */
322 return;
323 }
324
325 if (llvm_param.kbuild_dir && !llvm_param.kbuild_dir[0]) {
326 pr_debug("[llvm.kbuild-dir] is set to \"\" deliberately.\n");
327 pr_debug("Skip kbuild options detection.\n");
328 goto errout;
329 }
330
331 err = detect_kbuild_dir(kbuild_dir);
332 if (err) {
333 pr_warning(
334 "WARNING:\tunable to get correct kernel building directory.\n"
335 "Hint:\tSet correct kbuild directory using 'kbuild-dir' option in [llvm]\n"
336 " \tsection of ~/.perfconfig or set it to \"\" to suppress kbuild\n"
337 " \tdetection.\n\n");
338 goto errout;
339 }
340
341 pr_debug("Kernel build dir is set to %s\n", *kbuild_dir);
342 force_set_env("KBUILD_DIR", *kbuild_dir);
343 force_set_env("KBUILD_OPTS", llvm_param.kbuild_opts);
344 err = read_from_pipe(kinc_fetch_script,
345 (void **)kbuild_include_opts,
346 NULL);
347 if (err) {
348 pr_warning(
349 "WARNING:\tunable to get kernel include directories from '%s'\n"
350 "Hint:\tTry set clang include options using 'clang-bpf-cmd-template'\n"
351 " \toption in [llvm] section of ~/.perfconfig and set 'kbuild-dir'\n"
352 " \toption in [llvm] to \"\" to suppress this detection.\n\n",
353 *kbuild_dir);
354
355 free(*kbuild_dir);
356 *kbuild_dir = NULL;
357 goto errout;
358 }
359
360 pr_debug("include option is set to %s\n", *kbuild_include_opts);
361
362 saved_kbuild_dir = strdup(*kbuild_dir);
363 saved_kbuild_include_opts = strdup(*kbuild_include_opts);
364
365 if (!saved_kbuild_dir || !saved_kbuild_include_opts) {
366 zfree(&saved_kbuild_dir);
367 zfree(&saved_kbuild_include_opts);
368 }
369 return;
370 errout:
371 saved_kbuild_dir = ERR_PTR(-EINVAL);
372 saved_kbuild_include_opts = ERR_PTR(-EINVAL);
373 }
374
llvm__get_nr_cpus(void)375 int llvm__get_nr_cpus(void)
376 {
377 static int nr_cpus_avail = 0;
378 char serr[STRERR_BUFSIZE];
379
380 if (nr_cpus_avail > 0)
381 return nr_cpus_avail;
382
383 nr_cpus_avail = sysconf(_SC_NPROCESSORS_CONF);
384 if (nr_cpus_avail <= 0) {
385 pr_err(
386 "WARNING:\tunable to get available CPUs in this system: %s\n"
387 " \tUse 128 instead.\n", str_error_r(errno, serr, sizeof(serr)));
388 nr_cpus_avail = 128;
389 }
390 return nr_cpus_avail;
391 }
392
llvm__dump_obj(const char * path,void * obj_buf,size_t size)393 void llvm__dump_obj(const char *path, void *obj_buf, size_t size)
394 {
395 char *obj_path = strdup(path);
396 FILE *fp;
397 char *p;
398
399 if (!obj_path) {
400 pr_warning("WARNING: Not enough memory, skip object dumping\n");
401 return;
402 }
403
404 p = strrchr(obj_path, '.');
405 if (!p || (strcmp(p, ".c") != 0)) {
406 pr_warning("WARNING: invalid llvm source path: '%s', skip object dumping\n",
407 obj_path);
408 goto out;
409 }
410
411 p[1] = 'o';
412 fp = fopen(obj_path, "wb");
413 if (!fp) {
414 pr_warning("WARNING: failed to open '%s': %s, skip object dumping\n",
415 obj_path, strerror(errno));
416 goto out;
417 }
418
419 pr_info("LLVM: dumping %s\n", obj_path);
420 if (fwrite(obj_buf, size, 1, fp) != 1)
421 pr_warning("WARNING: failed to write to file '%s': %s, skip object dumping\n",
422 obj_path, strerror(errno));
423 fclose(fp);
424 out:
425 free(obj_path);
426 }
427
llvm__compile_bpf(const char * path,void ** p_obj_buf,size_t * p_obj_buf_sz)428 int llvm__compile_bpf(const char *path, void **p_obj_buf,
429 size_t *p_obj_buf_sz)
430 {
431 size_t obj_buf_sz;
432 void *obj_buf = NULL;
433 int err, nr_cpus_avail;
434 unsigned int kernel_version;
435 char linux_version_code_str[64];
436 const char *clang_opt = llvm_param.clang_opt;
437 char clang_path[PATH_MAX], llc_path[PATH_MAX], abspath[PATH_MAX], nr_cpus_avail_str[64];
438 char serr[STRERR_BUFSIZE];
439 char *kbuild_dir = NULL, *kbuild_include_opts = NULL,
440 *perf_bpf_include_opts = NULL;
441 const char *template = llvm_param.clang_bpf_cmd_template;
442 char *pipe_template = NULL;
443 const char *opts = llvm_param.opts;
444 char *command_echo = NULL, *command_out;
445 char *perf_include_dir = system_path(PERF_INCLUDE_DIR);
446
447 if (path[0] != '-' && realpath(path, abspath) == NULL) {
448 err = errno;
449 pr_err("ERROR: problems with path %s: %s\n",
450 path, str_error_r(err, serr, sizeof(serr)));
451 return -err;
452 }
453
454 if (!template)
455 template = CLANG_BPF_CMD_DEFAULT_TEMPLATE;
456
457 err = search_program(llvm_param.clang_path,
458 "clang", clang_path);
459 if (err) {
460 pr_err(
461 "ERROR:\tunable to find clang.\n"
462 "Hint:\tTry to install latest clang/llvm to support BPF. Check your $PATH\n"
463 " \tand 'clang-path' option in [llvm] section of ~/.perfconfig.\n");
464 version_notice();
465 return -ENOENT;
466 }
467
468 /*
469 * This is an optional work. Even it fail we can continue our
470 * work. Needn't to check error return.
471 */
472 llvm__get_kbuild_opts(&kbuild_dir, &kbuild_include_opts);
473
474 nr_cpus_avail = llvm__get_nr_cpus();
475 snprintf(nr_cpus_avail_str, sizeof(nr_cpus_avail_str), "%d",
476 nr_cpus_avail);
477
478 if (fetch_kernel_version(&kernel_version, NULL, 0))
479 kernel_version = 0;
480
481 snprintf(linux_version_code_str, sizeof(linux_version_code_str),
482 "0x%x", kernel_version);
483 if (asprintf(&perf_bpf_include_opts, "-I%s/bpf", perf_include_dir) < 0)
484 goto errout;
485 force_set_env("NR_CPUS", nr_cpus_avail_str);
486 force_set_env("LINUX_VERSION_CODE", linux_version_code_str);
487 force_set_env("CLANG_EXEC", clang_path);
488 force_set_env("CLANG_OPTIONS", clang_opt);
489 force_set_env("KERNEL_INC_OPTIONS", kbuild_include_opts);
490 force_set_env("PERF_BPF_INC_OPTIONS", perf_bpf_include_opts);
491 force_set_env("WORKING_DIR", kbuild_dir ? : ".");
492
493 if (opts) {
494 err = search_program(llvm_param.llc_path, "llc", llc_path);
495 if (err) {
496 pr_err("ERROR:\tunable to find llc.\n"
497 "Hint:\tTry to install latest clang/llvm to support BPF. Check your $PATH\n"
498 " \tand 'llc-path' option in [llvm] section of ~/.perfconfig.\n");
499 version_notice();
500 goto errout;
501 }
502
503 if (asprintf(&pipe_template, "%s -emit-llvm | %s -march=bpf %s -filetype=obj -o -",
504 template, llc_path, opts) < 0) {
505 pr_err("ERROR:\tnot enough memory to setup command line\n");
506 goto errout;
507 }
508
509 template = pipe_template;
510
511 }
512
513 /*
514 * Since we may reset clang's working dir, path of source file
515 * should be transferred into absolute path, except we want
516 * stdin to be source file (testing).
517 */
518 force_set_env("CLANG_SOURCE",
519 (path[0] == '-') ? path : abspath);
520
521 pr_debug("llvm compiling command template: %s\n", template);
522
523 if (asprintf(&command_echo, "echo -n \"%s\"", template) < 0)
524 goto errout;
525
526 err = read_from_pipe(command_echo, (void **) &command_out, NULL);
527 if (err)
528 goto errout;
529
530 pr_debug("llvm compiling command : %s\n", command_out);
531
532 err = read_from_pipe(template, &obj_buf, &obj_buf_sz);
533 if (err) {
534 pr_err("ERROR:\tunable to compile %s\n", path);
535 pr_err("Hint:\tCheck error message shown above.\n");
536 pr_err("Hint:\tYou can also pre-compile it into .o using:\n");
537 pr_err(" \t\tclang -target bpf -O2 -c %s\n", path);
538 pr_err(" \twith proper -I and -D options.\n");
539 goto errout;
540 }
541
542 free(command_echo);
543 free(command_out);
544 free(kbuild_dir);
545 free(kbuild_include_opts);
546 free(perf_bpf_include_opts);
547 free(perf_include_dir);
548
549 if (!p_obj_buf)
550 free(obj_buf);
551 else
552 *p_obj_buf = obj_buf;
553
554 if (p_obj_buf_sz)
555 *p_obj_buf_sz = obj_buf_sz;
556 return 0;
557 errout:
558 free(command_echo);
559 free(kbuild_dir);
560 free(kbuild_include_opts);
561 free(obj_buf);
562 free(perf_bpf_include_opts);
563 free(perf_include_dir);
564 free(pipe_template);
565 if (p_obj_buf)
566 *p_obj_buf = NULL;
567 if (p_obj_buf_sz)
568 *p_obj_buf_sz = 0;
569 return err;
570 }
571
llvm__search_clang(void)572 int llvm__search_clang(void)
573 {
574 char clang_path[PATH_MAX];
575
576 return search_program(llvm_param.clang_path, "clang", clang_path);
577 }
578
