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