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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 <unistd.h>
12#include <linux/err.h>
13#include <linux/string.h>
14#include <linux/zalloc.h>
15#include "debug.h"
16#include "llvm-utils.h"
17#include "config.h"
18#include "util.h"
19#include <sys/wait.h>
20#include <subcmd/exec-cmd.h>
21
22#define CLANG_BPF_CMD_DEFAULT_TEMPLATE \
23 "$CLANG_EXEC -D__KERNEL__ -D__NR_CPUS__=$NR_CPUS "\
24 "-DLINUX_VERSION_CODE=$LINUX_VERSION_CODE " \
25 "$CLANG_OPTIONS $PERF_BPF_INC_OPTIONS $KERNEL_INC_OPTIONS " \
26 "-Wno-unused-value -Wno-pointer-sign " \
27 "-working-directory $WORKING_DIR " \
28 "-c \"$CLANG_SOURCE\" -target bpf $CLANG_EMIT_LLVM -O2 -o - $LLVM_OPTIONS_PIPE"
29
30struct llvm_param llvm_param = {
31 .clang_path = "clang",
32 .llc_path = "llc",
33 .clang_bpf_cmd_template = CLANG_BPF_CMD_DEFAULT_TEMPLATE,
34 .clang_opt = NULL,
35 .opts = NULL,
36 .kbuild_dir = NULL,
37 .kbuild_opts = NULL,
38 .user_set_param = false,
39};
40
41int perf_llvm_config(const char *var, const char *value)
42{
43 if (!strstarts(var, "llvm."))
44 return 0;
45 var += sizeof("llvm.") - 1;
46
47 if (!strcmp(var, "clang-path"))
48 llvm_param.clang_path = strdup(value);
49 else if (!strcmp(var, "clang-bpf-cmd-template"))
50 llvm_param.clang_bpf_cmd_template = strdup(value);
51 else if (!strcmp(var, "clang-opt"))
52 llvm_param.clang_opt = strdup(value);
53 else if (!strcmp(var, "kbuild-dir"))
54 llvm_param.kbuild_dir = strdup(value);
55 else if (!strcmp(var, "kbuild-opts"))
56 llvm_param.kbuild_opts = strdup(value);
57 else if (!strcmp(var, "dump-obj"))
58 llvm_param.dump_obj = !!perf_config_bool(var, value);
59 else if (!strcmp(var, "opts"))
60 llvm_param.opts = strdup(value);
61 else {
62 pr_debug("Invalid LLVM config option: %s\n", value);
63 return -1;
64 }
65 llvm_param.user_set_param = true;
66 return 0;
67}
68
69static int
70search_program(const char *def, const char *name,
71 char *output)
72{
73 char *env, *path, *tmp = NULL;
74 char buf[PATH_MAX];
75 int ret;
76
77 output[0] = '\0';
78 if (def && def[0] != '\0') {
79 if (def[0] == '/') {
80 if (access(def, F_OK) == 0) {
81 strlcpy(output, def, PATH_MAX);
82 return 0;
83 }
84 } else if (def[0] != '\0')
85 name = def;
86 }
87
88 env = getenv("PATH");
89 if (!env)
90 return -1;
91 env = strdup(env);
92 if (!env)
93 return -1;
94
95 ret = -ENOENT;
96 path = strtok_r(env, ":", &tmp);
97 while (path) {
98 scnprintf(buf, sizeof(buf), "%s/%s", path, name);
99 if (access(buf, F_OK) == 0) {
100 strlcpy(output, buf, PATH_MAX);
101 ret = 0;
102 break;
103 }
104 path = strtok_r(NULL, ":", &tmp);
105 }
106
107 free(env);
108 return ret;
109}
110
111#define READ_SIZE 4096
112static int
113read_from_pipe(const char *cmd, void **p_buf, size_t *p_read_sz)
114{
115 int err = 0;
116 void *buf = NULL;
117 FILE *file = NULL;
118 size_t read_sz = 0, buf_sz = 0;
119 char serr[STRERR_BUFSIZE];
120
121 file = popen(cmd, "r");
122 if (!file) {
123 pr_err("ERROR: unable to popen cmd: %s\n",
124 str_error_r(errno, serr, sizeof(serr)));
125 return -EINVAL;
126 }
127
128 while (!feof(file) && !ferror(file)) {
129 /*
130 * Make buf_sz always have obe byte extra space so we
131 * can put '\0' there.
132 */
133 if (buf_sz - read_sz < READ_SIZE + 1) {
134 void *new_buf;
135
136 buf_sz = read_sz + READ_SIZE + 1;
137 new_buf = realloc(buf, buf_sz);
138
139 if (!new_buf) {
140 pr_err("ERROR: failed to realloc memory\n");
141 err = -ENOMEM;
142 goto errout;
143 }
144
145 buf = new_buf;
146 }
147 read_sz += fread(buf + read_sz, 1, READ_SIZE, file);
148 }
149
150 if (buf_sz - read_sz < 1) {
151 pr_err("ERROR: internal error\n");
152 err = -EINVAL;
153 goto errout;
154 }
155
156 if (ferror(file)) {
157 pr_err("ERROR: error occurred when reading from pipe: %s\n",
158 str_error_r(errno, serr, sizeof(serr)));
159 err = -EIO;
160 goto errout;
161 }
162
163 err = WEXITSTATUS(pclose(file));
164 file = NULL;
165 if (err) {
166 err = -EINVAL;
167 goto errout;
168 }
169
170 /*
171 * If buf is string, give it terminal '\0' to make our life
172 * easier. If buf is not string, that '\0' is out of space
173 * indicated by read_sz so caller won't even notice it.
174 */
175 ((char *)buf)[read_sz] = '\0';
176
177 if (!p_buf)
178 free(buf);
179 else
180 *p_buf = buf;
181
182 if (p_read_sz)
183 *p_read_sz = read_sz;
184 return 0;
185
186errout:
187 if (file)
188 pclose(file);
189 free(buf);
190 if (p_buf)
191 *p_buf = NULL;
192 if (p_read_sz)
193 *p_read_sz = 0;
194 return err;
195}
196
197static inline void
198force_set_env(const char *var, const char *value)
199{
200 if (value) {
201 setenv(var, value, 1);
202 pr_debug("set env: %s=%s\n", var, value);
203 } else {
204 unsetenv(var);
205 pr_debug("unset env: %s\n", var);
206 }
207}
208
209static void
210version_notice(void)
211{
212 pr_err(
213" \tLLVM 3.7 or newer is required. Which can be found from http://llvm.org\n"
214" \tYou may want to try git trunk:\n"
215" \t\tgit clone http://llvm.org/git/llvm.git\n"
216" \t\t and\n"
217" \t\tgit clone http://llvm.org/git/clang.git\n\n"
218" \tOr fetch the latest clang/llvm 3.7 from pre-built llvm packages for\n"
219" \tdebian/ubuntu:\n"
220" \t\thttp://llvm.org/apt\n\n"
221" \tIf you are using old version of clang, change 'clang-bpf-cmd-template'\n"
222" \toption in [llvm] section of ~/.perfconfig to:\n\n"
223" \t \"$CLANG_EXEC $CLANG_OPTIONS $KERNEL_INC_OPTIONS $PERF_BPF_INC_OPTIONS \\\n"
224" \t -working-directory $WORKING_DIR -c $CLANG_SOURCE \\\n"
225" \t -emit-llvm -o - | /path/to/llc -march=bpf -filetype=obj -o -\"\n"
226" \t(Replace /path/to/llc with path to your llc)\n\n"
227);
228}
229
230static int detect_kbuild_dir(char **kbuild_dir)
231{
232 const char *test_dir = llvm_param.kbuild_dir;
233 const char *prefix_dir = "";
234 const char *suffix_dir = "";
235
236 /* _UTSNAME_LENGTH is 65 */
237 char release[128];
238
239 char *autoconf_path;
240
241 int err;
242
243 if (!test_dir) {
244 err = fetch_kernel_version(NULL, release,
245 sizeof(release));
246 if (err)
247 return -EINVAL;
248
249 test_dir = release;
250 prefix_dir = "/lib/modules/";
251 suffix_dir = "/build";
252 }
253
254 err = asprintf(&autoconf_path, "%s%s%s/include/generated/autoconf.h",
255 prefix_dir, test_dir, suffix_dir);
256 if (err < 0)
257 return -ENOMEM;
258
259 if (access(autoconf_path, R_OK) == 0) {
260 free(autoconf_path);
261
262 err = asprintf(kbuild_dir, "%s%s%s", prefix_dir, test_dir,
263 suffix_dir);
264 if (err < 0)
265 return -ENOMEM;
266 return 0;
267 }
268 free(autoconf_path);
269 return -ENOENT;
270}
271
272static const char *kinc_fetch_script =
273"#!/usr/bin/env sh\n"
274"if ! test -d \"$KBUILD_DIR\"\n"
275"then\n"
276" exit 1\n"
277"fi\n"
278"if ! test -f \"$KBUILD_DIR/include/generated/autoconf.h\"\n"
279"then\n"
280" exit 1\n"
281"fi\n"
282"TMPDIR=`mktemp -d`\n"
283"if test -z \"$TMPDIR\"\n"
284"then\n"
285" exit 1\n"
286"fi\n"
287"cat << EOF > $TMPDIR/Makefile\n"
288"obj-y := dummy.o\n"
289"\\$(obj)/%.o: \\$(src)/%.c\n"
290"\t@echo -n \"\\$(NOSTDINC_FLAGS) \\$(LINUXINCLUDE) \\$(EXTRA_CFLAGS)\"\n"
291"EOF\n"
292"touch $TMPDIR/dummy.c\n"
293"make -s -C $KBUILD_DIR M=$TMPDIR $KBUILD_OPTS dummy.o 2>/dev/null\n"
294"RET=$?\n"
295"rm -rf $TMPDIR\n"
296"exit $RET\n";
297
298void llvm__get_kbuild_opts(char **kbuild_dir, char **kbuild_include_opts)
299{
300 static char *saved_kbuild_dir;
301 static char *saved_kbuild_include_opts;
302 int err;
303
304 if (!kbuild_dir || !kbuild_include_opts)
305 return;
306
307 *kbuild_dir = NULL;
308 *kbuild_include_opts = NULL;
309
310 if (saved_kbuild_dir && saved_kbuild_include_opts &&
311 !IS_ERR(saved_kbuild_dir) && !IS_ERR(saved_kbuild_include_opts)) {
312 *kbuild_dir = strdup(saved_kbuild_dir);
313 *kbuild_include_opts = strdup(saved_kbuild_include_opts);
314
315 if (*kbuild_dir && *kbuild_include_opts)
316 return;
317
318 zfree(kbuild_dir);
319 zfree(kbuild_include_opts);
320 /*
321 * Don't fall through: it may breaks saved_kbuild_dir and
322 * saved_kbuild_include_opts if detect them again when
323 * memory is low.
324 */
325 return;
326 }
327
328 if (llvm_param.kbuild_dir && !llvm_param.kbuild_dir[0]) {
329 pr_debug("[llvm.kbuild-dir] is set to \"\" deliberately.\n");
330 pr_debug("Skip kbuild options detection.\n");
331 goto errout;
332 }
333
334 err = detect_kbuild_dir(kbuild_dir);
335 if (err) {
336 pr_warning(
337"WARNING:\tunable to get correct kernel building directory.\n"
338"Hint:\tSet correct kbuild directory using 'kbuild-dir' option in [llvm]\n"
339" \tsection of ~/.perfconfig or set it to \"\" to suppress kbuild\n"
340" \tdetection.\n\n");
341 goto errout;
342 }
343
344 pr_debug("Kernel build dir is set to %s\n", *kbuild_dir);
345 force_set_env("KBUILD_DIR", *kbuild_dir);
346 force_set_env("KBUILD_OPTS", llvm_param.kbuild_opts);
347 err = read_from_pipe(kinc_fetch_script,
348 (void **)kbuild_include_opts,
349 NULL);
350 if (err) {
351 pr_warning(
352"WARNING:\tunable to get kernel include directories from '%s'\n"
353"Hint:\tTry set clang include options using 'clang-bpf-cmd-template'\n"
354" \toption in [llvm] section of ~/.perfconfig and set 'kbuild-dir'\n"
355" \toption in [llvm] to \"\" to suppress this detection.\n\n",
356 *kbuild_dir);
357
358 zfree(kbuild_dir);
359 goto errout;
360 }
361
362 pr_debug("include option is set to %s\n", *kbuild_include_opts);
363
364 saved_kbuild_dir = strdup(*kbuild_dir);
365 saved_kbuild_include_opts = strdup(*kbuild_include_opts);
366
367 if (!saved_kbuild_dir || !saved_kbuild_include_opts) {
368 zfree(&saved_kbuild_dir);
369 zfree(&saved_kbuild_include_opts);
370 }
371 return;
372errout:
373 saved_kbuild_dir = ERR_PTR(-EINVAL);
374 saved_kbuild_include_opts = ERR_PTR(-EINVAL);
375}
376
377int llvm__get_nr_cpus(void)
378{
379 static int nr_cpus_avail = 0;
380 char serr[STRERR_BUFSIZE];
381
382 if (nr_cpus_avail > 0)
383 return nr_cpus_avail;
384
385 nr_cpus_avail = sysconf(_SC_NPROCESSORS_CONF);
386 if (nr_cpus_avail <= 0) {
387 pr_err(
388"WARNING:\tunable to get available CPUs in this system: %s\n"
389" \tUse 128 instead.\n", str_error_r(errno, serr, sizeof(serr)));
390 nr_cpus_avail = 128;
391 }
392 return nr_cpus_avail;
393}
394
395void llvm__dump_obj(const char *path, void *obj_buf, size_t size)
396{
397 char *obj_path = strdup(path);
398 FILE *fp;
399 char *p;
400
401 if (!obj_path) {
402 pr_warning("WARNING: Not enough memory, skip object dumping\n");
403 return;
404 }
405
406 p = strrchr(obj_path, '.');
407 if (!p || (strcmp(p, ".c") != 0)) {
408 pr_warning("WARNING: invalid llvm source path: '%s', skip object dumping\n",
409 obj_path);
410 goto out;
411 }
412
413 p[1] = 'o';
414 fp = fopen(obj_path, "wb");
415 if (!fp) {
416 pr_warning("WARNING: failed to open '%s': %s, skip object dumping\n",
417 obj_path, strerror(errno));
418 goto out;
419 }
420
421 pr_info("LLVM: dumping %s\n", obj_path);
422 if (fwrite(obj_buf, size, 1, fp) != 1)
423 pr_warning("WARNING: failed to write to file '%s': %s, skip object dumping\n",
424 obj_path, strerror(errno));
425 fclose(fp);
426out:
427 free(obj_path);
428}
429
430int llvm__compile_bpf(const char *path, void **p_obj_buf,
431 size_t *p_obj_buf_sz)
432{
433 size_t obj_buf_sz;
434 void *obj_buf = NULL;
435 int err, nr_cpus_avail;
436 unsigned int kernel_version;
437 char linux_version_code_str[64];
438 const char *clang_opt = llvm_param.clang_opt;
439 char clang_path[PATH_MAX], llc_path[PATH_MAX], abspath[PATH_MAX], nr_cpus_avail_str[64];
440 char serr[STRERR_BUFSIZE];
441 char *kbuild_dir = NULL, *kbuild_include_opts = NULL,
442 *perf_bpf_include_opts = NULL;
443 const char *template = llvm_param.clang_bpf_cmd_template;
444 char *pipe_template = NULL;
445 const char *opts = llvm_param.opts;
446 char *command_echo = NULL, *command_out;
447 char *perf_include_dir = system_path(PERF_INCLUDE_DIR);
448
449 if (path[0] != '-' && realpath(path, abspath) == NULL) {
450 err = errno;
451 pr_err("ERROR: problems with path %s: %s\n",
452 path, str_error_r(err, serr, sizeof(serr)));
453 return -err;
454 }
455
456 if (!template)
457 template = CLANG_BPF_CMD_DEFAULT_TEMPLATE;
458
459 err = search_program(llvm_param.clang_path,
460 "clang", clang_path);
461 if (err) {
462 pr_err(
463"ERROR:\tunable to find clang.\n"
464"Hint:\tTry to install latest clang/llvm to support BPF. Check your $PATH\n"
465" \tand 'clang-path' option in [llvm] section of ~/.perfconfig.\n");
466 version_notice();
467 return -ENOENT;
468 }
469
470 /*
471 * This is an optional work. Even it fail we can continue our
472 * work. Needn't to check error return.
473 */
474 llvm__get_kbuild_opts(&kbuild_dir, &kbuild_include_opts);
475
476 nr_cpus_avail = llvm__get_nr_cpus();
477 snprintf(nr_cpus_avail_str, sizeof(nr_cpus_avail_str), "%d",
478 nr_cpus_avail);
479
480 if (fetch_kernel_version(&kernel_version, NULL, 0))
481 kernel_version = 0;
482
483 snprintf(linux_version_code_str, sizeof(linux_version_code_str),
484 "0x%x", kernel_version);
485 if (asprintf(&perf_bpf_include_opts, "-I%s/bpf", perf_include_dir) < 0)
486 goto errout;
487 force_set_env("NR_CPUS", nr_cpus_avail_str);
488 force_set_env("LINUX_VERSION_CODE", linux_version_code_str);
489 force_set_env("CLANG_EXEC", clang_path);
490 force_set_env("CLANG_OPTIONS", clang_opt);
491 force_set_env("KERNEL_INC_OPTIONS", kbuild_include_opts);
492 force_set_env("PERF_BPF_INC_OPTIONS", perf_bpf_include_opts);
493 force_set_env("WORKING_DIR", kbuild_dir ? : ".");
494
495 if (opts) {
496 err = search_program(llvm_param.llc_path, "llc", llc_path);
497 if (err) {
498 pr_err("ERROR:\tunable to find llc.\n"
499 "Hint:\tTry to install latest clang/llvm to support BPF. Check your $PATH\n"
500 " \tand 'llc-path' option in [llvm] section of ~/.perfconfig.\n");
501 version_notice();
502 goto errout;
503 }
504
505 if (asprintf(&pipe_template, "%s -emit-llvm | %s -march=bpf %s -filetype=obj -o -",
506 template, llc_path, opts) < 0) {
507 pr_err("ERROR:\tnot enough memory to setup command line\n");
508 goto errout;
509 }
510
511 template = pipe_template;
512
513 }
514
515 /*
516 * Since we may reset clang's working dir, path of source file
517 * should be transferred into absolute path, except we want
518 * stdin to be source file (testing).
519 */
520 force_set_env("CLANG_SOURCE",
521 (path[0] == '-') ? path : abspath);
522
523 pr_debug("llvm compiling command template: %s\n", template);
524
525 if (asprintf(&command_echo, "echo -n \"%s\"", template) < 0)
526 goto errout;
527
528 err = read_from_pipe(command_echo, (void **) &command_out, NULL);
529 if (err)
530 goto errout;
531
532 pr_debug("llvm compiling command : %s\n", command_out);
533
534 err = read_from_pipe(template, &obj_buf, &obj_buf_sz);
535 if (err) {
536 pr_err("ERROR:\tunable to compile %s\n", path);
537 pr_err("Hint:\tCheck error message shown above.\n");
538 pr_err("Hint:\tYou can also pre-compile it into .o using:\n");
539 pr_err(" \t\tclang -target bpf -O2 -c %s\n", path);
540 pr_err(" \twith proper -I and -D options.\n");
541 goto errout;
542 }
543
544 free(command_echo);
545 free(command_out);
546 free(kbuild_dir);
547 free(kbuild_include_opts);
548 free(perf_bpf_include_opts);
549 free(perf_include_dir);
550
551 if (!p_obj_buf)
552 free(obj_buf);
553 else
554 *p_obj_buf = obj_buf;
555
556 if (p_obj_buf_sz)
557 *p_obj_buf_sz = obj_buf_sz;
558 return 0;
559errout:
560 free(command_echo);
561 free(kbuild_dir);
562 free(kbuild_include_opts);
563 free(obj_buf);
564 free(perf_bpf_include_opts);
565 free(perf_include_dir);
566 free(pipe_template);
567 if (p_obj_buf)
568 *p_obj_buf = NULL;
569 if (p_obj_buf_sz)
570 *p_obj_buf_sz = 0;
571 return err;
572}
573
574int llvm__search_clang(void)
575{
576 char clang_path[PATH_MAX];
577
578 return search_program(llvm_param.clang_path, "clang", clang_path);
579}