Loading...
Note: File does not exist in v3.15.
1/*
2 * Copyright (C) 2015, Wang Nan <wangnan0@huawei.com>
3 * Copyright (C) 2015, Huawei Inc.
4 */
5
6#include <errno.h>
7#include <limits.h>
8#include <stdio.h>
9#include <stdlib.h>
10#include <linux/err.h>
11#include "debug.h"
12#include "llvm-utils.h"
13#include "config.h"
14#include "util.h"
15
16#define CLANG_BPF_CMD_DEFAULT_TEMPLATE \
17 "$CLANG_EXEC -D__KERNEL__ -D__NR_CPUS__=$NR_CPUS "\
18 "-DLINUX_VERSION_CODE=$LINUX_VERSION_CODE " \
19 "$CLANG_OPTIONS $KERNEL_INC_OPTIONS " \
20 "-Wno-unused-value -Wno-pointer-sign " \
21 "-working-directory $WORKING_DIR " \
22 "-c \"$CLANG_SOURCE\" -target bpf -O2 -o -"
23
24struct llvm_param llvm_param = {
25 .clang_path = "clang",
26 .clang_bpf_cmd_template = CLANG_BPF_CMD_DEFAULT_TEMPLATE,
27 .clang_opt = NULL,
28 .kbuild_dir = NULL,
29 .kbuild_opts = NULL,
30 .user_set_param = false,
31};
32
33int perf_llvm_config(const char *var, const char *value)
34{
35 if (prefixcmp(var, "llvm."))
36 return 0;
37 var += sizeof("llvm.") - 1;
38
39 if (!strcmp(var, "clang-path"))
40 llvm_param.clang_path = strdup(value);
41 else if (!strcmp(var, "clang-bpf-cmd-template"))
42 llvm_param.clang_bpf_cmd_template = strdup(value);
43 else if (!strcmp(var, "clang-opt"))
44 llvm_param.clang_opt = strdup(value);
45 else if (!strcmp(var, "kbuild-dir"))
46 llvm_param.kbuild_dir = strdup(value);
47 else if (!strcmp(var, "kbuild-opts"))
48 llvm_param.kbuild_opts = strdup(value);
49 else if (!strcmp(var, "dump-obj"))
50 llvm_param.dump_obj = !!perf_config_bool(var, value);
51 else
52 return -1;
53 llvm_param.user_set_param = true;
54 return 0;
55}
56
57static int
58search_program(const char *def, const char *name,
59 char *output)
60{
61 char *env, *path, *tmp = NULL;
62 char buf[PATH_MAX];
63 int ret;
64
65 output[0] = '\0';
66 if (def && def[0] != '\0') {
67 if (def[0] == '/') {
68 if (access(def, F_OK) == 0) {
69 strlcpy(output, def, PATH_MAX);
70 return 0;
71 }
72 } else if (def[0] != '\0')
73 name = def;
74 }
75
76 env = getenv("PATH");
77 if (!env)
78 return -1;
79 env = strdup(env);
80 if (!env)
81 return -1;
82
83 ret = -ENOENT;
84 path = strtok_r(env, ":", &tmp);
85 while (path) {
86 scnprintf(buf, sizeof(buf), "%s/%s", path, name);
87 if (access(buf, F_OK) == 0) {
88 strlcpy(output, buf, PATH_MAX);
89 ret = 0;
90 break;
91 }
92 path = strtok_r(NULL, ":", &tmp);
93 }
94
95 free(env);
96 return ret;
97}
98
99#define READ_SIZE 4096
100static int
101read_from_pipe(const char *cmd, void **p_buf, size_t *p_read_sz)
102{
103 int err = 0;
104 void *buf = NULL;
105 FILE *file = NULL;
106 size_t read_sz = 0, buf_sz = 0;
107 char serr[STRERR_BUFSIZE];
108
109 file = popen(cmd, "r");
110 if (!file) {
111 pr_err("ERROR: unable to popen cmd: %s\n",
112 str_error_r(errno, serr, sizeof(serr)));
113 return -EINVAL;
114 }
115
116 while (!feof(file) && !ferror(file)) {
117 /*
118 * Make buf_sz always have obe byte extra space so we
119 * can put '\0' there.
120 */
121 if (buf_sz - read_sz < READ_SIZE + 1) {
122 void *new_buf;
123
124 buf_sz = read_sz + READ_SIZE + 1;
125 new_buf = realloc(buf, buf_sz);
126
127 if (!new_buf) {
128 pr_err("ERROR: failed to realloc memory\n");
129 err = -ENOMEM;
130 goto errout;
131 }
132
133 buf = new_buf;
134 }
135 read_sz += fread(buf + read_sz, 1, READ_SIZE, file);
136 }
137
138 if (buf_sz - read_sz < 1) {
139 pr_err("ERROR: internal error\n");
140 err = -EINVAL;
141 goto errout;
142 }
143
144 if (ferror(file)) {
145 pr_err("ERROR: error occurred when reading from pipe: %s\n",
146 str_error_r(errno, serr, sizeof(serr)));
147 err = -EIO;
148 goto errout;
149 }
150
151 err = WEXITSTATUS(pclose(file));
152 file = NULL;
153 if (err) {
154 err = -EINVAL;
155 goto errout;
156 }
157
158 /*
159 * If buf is string, give it terminal '\0' to make our life
160 * easier. If buf is not string, that '\0' is out of space
161 * indicated by read_sz so caller won't even notice it.
162 */
163 ((char *)buf)[read_sz] = '\0';
164
165 if (!p_buf)
166 free(buf);
167 else
168 *p_buf = buf;
169
170 if (p_read_sz)
171 *p_read_sz = read_sz;
172 return 0;
173
174errout:
175 if (file)
176 pclose(file);
177 free(buf);
178 if (p_buf)
179 *p_buf = NULL;
180 if (p_read_sz)
181 *p_read_sz = 0;
182 return err;
183}
184
185static inline void
186force_set_env(const char *var, const char *value)
187{
188 if (value) {
189 setenv(var, value, 1);
190 pr_debug("set env: %s=%s\n", var, value);
191 } else {
192 unsetenv(var);
193 pr_debug("unset env: %s\n", var);
194 }
195}
196
197static void
198version_notice(void)
199{
200 pr_err(
201" \tLLVM 3.7 or newer is required. Which can be found from http://llvm.org\n"
202" \tYou may want to try git trunk:\n"
203" \t\tgit clone http://llvm.org/git/llvm.git\n"
204" \t\t and\n"
205" \t\tgit clone http://llvm.org/git/clang.git\n\n"
206" \tOr fetch the latest clang/llvm 3.7 from pre-built llvm packages for\n"
207" \tdebian/ubuntu:\n"
208" \t\thttp://llvm.org/apt\n\n"
209" \tIf you are using old version of clang, change 'clang-bpf-cmd-template'\n"
210" \toption in [llvm] section of ~/.perfconfig to:\n\n"
211" \t \"$CLANG_EXEC $CLANG_OPTIONS $KERNEL_INC_OPTIONS \\\n"
212" \t -working-directory $WORKING_DIR -c $CLANG_SOURCE \\\n"
213" \t -emit-llvm -o - | /path/to/llc -march=bpf -filetype=obj -o -\"\n"
214" \t(Replace /path/to/llc with path to your llc)\n\n"
215);
216}
217
218static int detect_kbuild_dir(char **kbuild_dir)
219{
220 const char *test_dir = llvm_param.kbuild_dir;
221 const char *prefix_dir = "";
222 const char *suffix_dir = "";
223
224 char *autoconf_path;
225
226 int err;
227
228 if (!test_dir) {
229 /* _UTSNAME_LENGTH is 65 */
230 char release[128];
231
232 err = fetch_kernel_version(NULL, release,
233 sizeof(release));
234 if (err)
235 return -EINVAL;
236
237 test_dir = release;
238 prefix_dir = "/lib/modules/";
239 suffix_dir = "/build";
240 }
241
242 err = asprintf(&autoconf_path, "%s%s%s/include/generated/autoconf.h",
243 prefix_dir, test_dir, suffix_dir);
244 if (err < 0)
245 return -ENOMEM;
246
247 if (access(autoconf_path, R_OK) == 0) {
248 free(autoconf_path);
249
250 err = asprintf(kbuild_dir, "%s%s%s", prefix_dir, test_dir,
251 suffix_dir);
252 if (err < 0)
253 return -ENOMEM;
254 return 0;
255 }
256 free(autoconf_path);
257 return -ENOENT;
258}
259
260static const char *kinc_fetch_script =
261"#!/usr/bin/env sh\n"
262"if ! test -d \"$KBUILD_DIR\"\n"
263"then\n"
264" exit -1\n"
265"fi\n"
266"if ! test -f \"$KBUILD_DIR/include/generated/autoconf.h\"\n"
267"then\n"
268" exit -1\n"
269"fi\n"
270"TMPDIR=`mktemp -d`\n"
271"if test -z \"$TMPDIR\"\n"
272"then\n"
273" exit -1\n"
274"fi\n"
275"cat << EOF > $TMPDIR/Makefile\n"
276"obj-y := dummy.o\n"
277"\\$(obj)/%.o: \\$(src)/%.c\n"
278"\t@echo -n \"\\$(NOSTDINC_FLAGS) \\$(LINUXINCLUDE) \\$(EXTRA_CFLAGS)\"\n"
279"EOF\n"
280"touch $TMPDIR/dummy.c\n"
281"make -s -C $KBUILD_DIR M=$TMPDIR $KBUILD_OPTS dummy.o 2>/dev/null\n"
282"RET=$?\n"
283"rm -rf $TMPDIR\n"
284"exit $RET\n";
285
286void llvm__get_kbuild_opts(char **kbuild_dir, char **kbuild_include_opts)
287{
288 static char *saved_kbuild_dir;
289 static char *saved_kbuild_include_opts;
290 int err;
291
292 if (!kbuild_dir || !kbuild_include_opts)
293 return;
294
295 *kbuild_dir = NULL;
296 *kbuild_include_opts = NULL;
297
298 if (saved_kbuild_dir && saved_kbuild_include_opts &&
299 !IS_ERR(saved_kbuild_dir) && !IS_ERR(saved_kbuild_include_opts)) {
300 *kbuild_dir = strdup(saved_kbuild_dir);
301 *kbuild_include_opts = strdup(saved_kbuild_include_opts);
302
303 if (*kbuild_dir && *kbuild_include_opts)
304 return;
305
306 zfree(kbuild_dir);
307 zfree(kbuild_include_opts);
308 /*
309 * Don't fall through: it may breaks saved_kbuild_dir and
310 * saved_kbuild_include_opts if detect them again when
311 * memory is low.
312 */
313 return;
314 }
315
316 if (llvm_param.kbuild_dir && !llvm_param.kbuild_dir[0]) {
317 pr_debug("[llvm.kbuild-dir] is set to \"\" deliberately.\n");
318 pr_debug("Skip kbuild options detection.\n");
319 goto errout;
320 }
321
322 err = detect_kbuild_dir(kbuild_dir);
323 if (err) {
324 pr_warning(
325"WARNING:\tunable to get correct kernel building directory.\n"
326"Hint:\tSet correct kbuild directory using 'kbuild-dir' option in [llvm]\n"
327" \tsection of ~/.perfconfig or set it to \"\" to suppress kbuild\n"
328" \tdetection.\n\n");
329 goto errout;
330 }
331
332 pr_debug("Kernel build dir is set to %s\n", *kbuild_dir);
333 force_set_env("KBUILD_DIR", *kbuild_dir);
334 force_set_env("KBUILD_OPTS", llvm_param.kbuild_opts);
335 err = read_from_pipe(kinc_fetch_script,
336 (void **)kbuild_include_opts,
337 NULL);
338 if (err) {
339 pr_warning(
340"WARNING:\tunable to get kernel include directories from '%s'\n"
341"Hint:\tTry set clang include options using 'clang-bpf-cmd-template'\n"
342" \toption in [llvm] section of ~/.perfconfig and set 'kbuild-dir'\n"
343" \toption in [llvm] to \"\" to suppress this detection.\n\n",
344 *kbuild_dir);
345
346 free(*kbuild_dir);
347 *kbuild_dir = NULL;
348 goto errout;
349 }
350
351 pr_debug("include option is set to %s\n", *kbuild_include_opts);
352
353 saved_kbuild_dir = strdup(*kbuild_dir);
354 saved_kbuild_include_opts = strdup(*kbuild_include_opts);
355
356 if (!saved_kbuild_dir || !saved_kbuild_include_opts) {
357 zfree(&saved_kbuild_dir);
358 zfree(&saved_kbuild_include_opts);
359 }
360 return;
361errout:
362 saved_kbuild_dir = ERR_PTR(-EINVAL);
363 saved_kbuild_include_opts = ERR_PTR(-EINVAL);
364}
365
366int llvm__get_nr_cpus(void)
367{
368 static int nr_cpus_avail = 0;
369 char serr[STRERR_BUFSIZE];
370
371 if (nr_cpus_avail > 0)
372 return nr_cpus_avail;
373
374 nr_cpus_avail = sysconf(_SC_NPROCESSORS_CONF);
375 if (nr_cpus_avail <= 0) {
376 pr_err(
377"WARNING:\tunable to get available CPUs in this system: %s\n"
378" \tUse 128 instead.\n", str_error_r(errno, serr, sizeof(serr)));
379 nr_cpus_avail = 128;
380 }
381 return nr_cpus_avail;
382}
383
384void llvm__dump_obj(const char *path, void *obj_buf, size_t size)
385{
386 char *obj_path = strdup(path);
387 FILE *fp;
388 char *p;
389
390 if (!obj_path) {
391 pr_warning("WARNING: Not enough memory, skip object dumping\n");
392 return;
393 }
394
395 p = strrchr(obj_path, '.');
396 if (!p || (strcmp(p, ".c") != 0)) {
397 pr_warning("WARNING: invalid llvm source path: '%s', skip object dumping\n",
398 obj_path);
399 goto out;
400 }
401
402 p[1] = 'o';
403 fp = fopen(obj_path, "wb");
404 if (!fp) {
405 pr_warning("WARNING: failed to open '%s': %s, skip object dumping\n",
406 obj_path, strerror(errno));
407 goto out;
408 }
409
410 pr_info("LLVM: dumping %s\n", obj_path);
411 if (fwrite(obj_buf, size, 1, fp) != 1)
412 pr_warning("WARNING: failed to write to file '%s': %s, skip object dumping\n",
413 obj_path, strerror(errno));
414 fclose(fp);
415out:
416 free(obj_path);
417}
418
419int llvm__compile_bpf(const char *path, void **p_obj_buf,
420 size_t *p_obj_buf_sz)
421{
422 size_t obj_buf_sz;
423 void *obj_buf = NULL;
424 int err, nr_cpus_avail;
425 unsigned int kernel_version;
426 char linux_version_code_str[64];
427 const char *clang_opt = llvm_param.clang_opt;
428 char clang_path[PATH_MAX], abspath[PATH_MAX], nr_cpus_avail_str[64];
429 char serr[STRERR_BUFSIZE];
430 char *kbuild_dir = NULL, *kbuild_include_opts = NULL;
431 const char *template = llvm_param.clang_bpf_cmd_template;
432
433 if (path[0] != '-' && realpath(path, abspath) == NULL) {
434 err = errno;
435 pr_err("ERROR: problems with path %s: %s\n",
436 path, str_error_r(err, serr, sizeof(serr)));
437 return -err;
438 }
439
440 if (!template)
441 template = CLANG_BPF_CMD_DEFAULT_TEMPLATE;
442
443 err = search_program(llvm_param.clang_path,
444 "clang", clang_path);
445 if (err) {
446 pr_err(
447"ERROR:\tunable to find clang.\n"
448"Hint:\tTry to install latest clang/llvm to support BPF. Check your $PATH\n"
449" \tand 'clang-path' option in [llvm] section of ~/.perfconfig.\n");
450 version_notice();
451 return -ENOENT;
452 }
453
454 /*
455 * This is an optional work. Even it fail we can continue our
456 * work. Needn't to check error return.
457 */
458 llvm__get_kbuild_opts(&kbuild_dir, &kbuild_include_opts);
459
460 nr_cpus_avail = llvm__get_nr_cpus();
461 snprintf(nr_cpus_avail_str, sizeof(nr_cpus_avail_str), "%d",
462 nr_cpus_avail);
463
464 if (fetch_kernel_version(&kernel_version, NULL, 0))
465 kernel_version = 0;
466
467 snprintf(linux_version_code_str, sizeof(linux_version_code_str),
468 "0x%x", kernel_version);
469
470 force_set_env("NR_CPUS", nr_cpus_avail_str);
471 force_set_env("LINUX_VERSION_CODE", linux_version_code_str);
472 force_set_env("CLANG_EXEC", clang_path);
473 force_set_env("CLANG_OPTIONS", clang_opt);
474 force_set_env("KERNEL_INC_OPTIONS", kbuild_include_opts);
475 force_set_env("WORKING_DIR", kbuild_dir ? : ".");
476
477 /*
478 * Since we may reset clang's working dir, path of source file
479 * should be transferred into absolute path, except we want
480 * stdin to be source file (testing).
481 */
482 force_set_env("CLANG_SOURCE",
483 (path[0] == '-') ? path : abspath);
484
485 pr_debug("llvm compiling command template: %s\n", template);
486 err = read_from_pipe(template, &obj_buf, &obj_buf_sz);
487 if (err) {
488 pr_err("ERROR:\tunable to compile %s\n", path);
489 pr_err("Hint:\tCheck error message shown above.\n");
490 pr_err("Hint:\tYou can also pre-compile it into .o using:\n");
491 pr_err(" \t\tclang -target bpf -O2 -c %s\n", path);
492 pr_err(" \twith proper -I and -D options.\n");
493 goto errout;
494 }
495
496 free(kbuild_dir);
497 free(kbuild_include_opts);
498
499 if (!p_obj_buf)
500 free(obj_buf);
501 else
502 *p_obj_buf = obj_buf;
503
504 if (p_obj_buf_sz)
505 *p_obj_buf_sz = obj_buf_sz;
506 return 0;
507errout:
508 free(kbuild_dir);
509 free(kbuild_include_opts);
510 free(obj_buf);
511 if (p_obj_buf)
512 *p_obj_buf = NULL;
513 if (p_obj_buf_sz)
514 *p_obj_buf_sz = 0;
515 return err;
516}
517
518int llvm__search_clang(void)
519{
520 char clang_path[PATH_MAX];
521
522 return search_program(llvm_param.clang_path, "clang", clang_path);
523}