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-rw-r--r--kernel/trace/trace_ksym.c508
1 files changed, 0 insertions, 508 deletions
diff --git a/kernel/trace/trace_ksym.c b/kernel/trace/trace_ksym.c
deleted file mode 100644
index 8eaf00749b65..000000000000
--- a/kernel/trace/trace_ksym.c
+++ /dev/null
@@ -1,508 +0,0 @@
1/*
2 * trace_ksym.c - Kernel Symbol Tracer
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
17 *
18 * Copyright (C) IBM Corporation, 2009
19 */
20
21#include <linux/kallsyms.h>
22#include <linux/uaccess.h>
23#include <linux/debugfs.h>
24#include <linux/ftrace.h>
25#include <linux/module.h>
26#include <linux/slab.h>
27#include <linux/fs.h>
28
29#include "trace_output.h"
30#include "trace.h"
31
32#include <linux/hw_breakpoint.h>
33#include <asm/hw_breakpoint.h>
34
35#include <asm/atomic.h>
36
37#define KSYM_TRACER_OP_LEN 3 /* rw- */
38
39struct trace_ksym {
40 struct perf_event **ksym_hbp;
41 struct perf_event_attr attr;
42#ifdef CONFIG_PROFILE_KSYM_TRACER
43 atomic64_t counter;
44#endif
45 struct hlist_node ksym_hlist;
46};
47
48static struct trace_array *ksym_trace_array;
49
50static unsigned int ksym_tracing_enabled;
51
52static HLIST_HEAD(ksym_filter_head);
53
54static DEFINE_MUTEX(ksym_tracer_mutex);
55
56#ifdef CONFIG_PROFILE_KSYM_TRACER
57
58#define MAX_UL_INT 0xffffffff
59
60void ksym_collect_stats(unsigned long hbp_hit_addr)
61{
62 struct hlist_node *node;
63 struct trace_ksym *entry;
64
65 rcu_read_lock();
66 hlist_for_each_entry_rcu(entry, node, &ksym_filter_head, ksym_hlist) {
67 if (entry->attr.bp_addr == hbp_hit_addr) {
68 atomic64_inc(&entry->counter);
69 break;
70 }
71 }
72 rcu_read_unlock();
73}
74#endif /* CONFIG_PROFILE_KSYM_TRACER */
75
76void ksym_hbp_handler(struct perf_event *hbp, int nmi,
77 struct perf_sample_data *data,
78 struct pt_regs *regs)
79{
80 struct ring_buffer_event *event;
81 struct ksym_trace_entry *entry;
82 struct ring_buffer *buffer;
83 int pc;
84
85 if (!ksym_tracing_enabled)
86 return;
87
88 buffer = ksym_trace_array->buffer;
89
90 pc = preempt_count();
91
92 event = trace_buffer_lock_reserve(buffer, TRACE_KSYM,
93 sizeof(*entry), 0, pc);
94 if (!event)
95 return;
96
97 entry = ring_buffer_event_data(event);
98 entry->ip = instruction_pointer(regs);
99 entry->type = hw_breakpoint_type(hbp);
100 entry->addr = hw_breakpoint_addr(hbp);
101 strlcpy(entry->cmd, current->comm, TASK_COMM_LEN);
102
103#ifdef CONFIG_PROFILE_KSYM_TRACER
104 ksym_collect_stats(hw_breakpoint_addr(hbp));
105#endif /* CONFIG_PROFILE_KSYM_TRACER */
106
107 trace_buffer_unlock_commit(buffer, event, 0, pc);
108}
109
110/* Valid access types are represented as
111 *
112 * rw- : Set Read/Write Access Breakpoint
113 * -w- : Set Write Access Breakpoint
114 * --- : Clear Breakpoints
115 * --x : Set Execution Break points (Not available yet)
116 *
117 */
118static int ksym_trace_get_access_type(char *str)
119{
120 int access = 0;
121
122 if (str[0] == 'r')
123 access |= HW_BREAKPOINT_R;
124
125 if (str[1] == 'w')
126 access |= HW_BREAKPOINT_W;
127
128 if (str[2] == 'x')
129 access |= HW_BREAKPOINT_X;
130
131 switch (access) {
132 case HW_BREAKPOINT_R:
133 case HW_BREAKPOINT_W:
134 case HW_BREAKPOINT_W | HW_BREAKPOINT_R:
135 return access;
136 default:
137 return -EINVAL;
138 }
139}
140
141/*
142 * There can be several possible malformed requests and we attempt to capture
143 * all of them. We enumerate some of the rules
144 * 1. We will not allow kernel symbols with ':' since it is used as a delimiter.
145 * i.e. multiple ':' symbols disallowed. Possible uses are of the form
146 * <module>:<ksym_name>:<op>.
147 * 2. No delimiter symbol ':' in the input string
148 * 3. Spurious operator symbols or symbols not in their respective positions
149 * 4. <ksym_name>:--- i.e. clear breakpoint request when ksym_name not in file
150 * 5. Kernel symbol not a part of /proc/kallsyms
151 * 6. Duplicate requests
152 */
153static int parse_ksym_trace_str(char *input_string, char **ksymname,
154 unsigned long *addr)
155{
156 int ret;
157
158 *ksymname = strsep(&input_string, ":");
159 *addr = kallsyms_lookup_name(*ksymname);
160
161 /* Check for malformed request: (2), (1) and (5) */
162 if ((!input_string) ||
163 (strlen(input_string) != KSYM_TRACER_OP_LEN) ||
164 (*addr == 0))
165 return -EINVAL;;
166
167 ret = ksym_trace_get_access_type(input_string);
168
169 return ret;
170}
171
172int process_new_ksym_entry(char *ksymname, int op, unsigned long addr)
173{
174 struct trace_ksym *entry;
175 int ret = -ENOMEM;
176
177 entry = kzalloc(sizeof(struct trace_ksym), GFP_KERNEL);
178 if (!entry)
179 return -ENOMEM;
180
181 hw_breakpoint_init(&entry->attr);
182
183 entry->attr.bp_type = op;
184 entry->attr.bp_addr = addr;
185 entry->attr.bp_len = HW_BREAKPOINT_LEN_4;
186
187 entry->ksym_hbp = register_wide_hw_breakpoint(&entry->attr,
188 ksym_hbp_handler);
189
190 if (IS_ERR(entry->ksym_hbp)) {
191 ret = PTR_ERR(entry->ksym_hbp);
192 if (ret == -ENOSPC) {
193 printk(KERN_ERR "ksym_tracer: Maximum limit reached."
194 " No new requests for tracing can be accepted now.\n");
195 } else {
196 printk(KERN_INFO "ksym_tracer request failed. Try again"
197 " later!!\n");
198 }
199 goto err;
200 }
201
202 hlist_add_head_rcu(&(entry->ksym_hlist), &ksym_filter_head);
203
204 return 0;
205
206err:
207 kfree(entry);
208
209 return ret;
210}
211
212static ssize_t ksym_trace_filter_read(struct file *filp, char __user *ubuf,
213 size_t count, loff_t *ppos)
214{
215 struct trace_ksym *entry;
216 struct hlist_node *node;
217 struct trace_seq *s;
218 ssize_t cnt = 0;
219 int ret;
220
221 s = kmalloc(sizeof(*s), GFP_KERNEL);
222 if (!s)
223 return -ENOMEM;
224 trace_seq_init(s);
225
226 mutex_lock(&ksym_tracer_mutex);
227
228 hlist_for_each_entry(entry, node, &ksym_filter_head, ksym_hlist) {
229 ret = trace_seq_printf(s, "%pS:",
230 (void *)(unsigned long)entry->attr.bp_addr);
231 if (entry->attr.bp_type == HW_BREAKPOINT_R)
232 ret = trace_seq_puts(s, "r--\n");
233 else if (entry->attr.bp_type == HW_BREAKPOINT_W)
234 ret = trace_seq_puts(s, "-w-\n");
235 else if (entry->attr.bp_type == (HW_BREAKPOINT_W | HW_BREAKPOINT_R))
236 ret = trace_seq_puts(s, "rw-\n");
237 WARN_ON_ONCE(!ret);
238 }
239
240 cnt = simple_read_from_buffer(ubuf, count, ppos, s->buffer, s->len);
241
242 mutex_unlock(&ksym_tracer_mutex);
243
244 kfree(s);
245
246 return cnt;
247}
248
249static void __ksym_trace_reset(void)
250{
251 struct trace_ksym *entry;
252 struct hlist_node *node, *node1;
253
254 mutex_lock(&ksym_tracer_mutex);
255 hlist_for_each_entry_safe(entry, node, node1, &ksym_filter_head,
256 ksym_hlist) {
257 unregister_wide_hw_breakpoint(entry->ksym_hbp);
258 hlist_del_rcu(&(entry->ksym_hlist));
259 synchronize_rcu();
260 kfree(entry);
261 }
262 mutex_unlock(&ksym_tracer_mutex);
263}
264
265static ssize_t ksym_trace_filter_write(struct file *file,
266 const char __user *buffer,
267 size_t count, loff_t *ppos)
268{
269 struct trace_ksym *entry;
270 struct hlist_node *node;
271 char *buf, *input_string, *ksymname = NULL;
272 unsigned long ksym_addr = 0;
273 int ret, op, changed = 0;
274
275 buf = kzalloc(count + 1, GFP_KERNEL);
276 if (!buf)
277 return -ENOMEM;
278
279 ret = -EFAULT;
280 if (copy_from_user(buf, buffer, count))
281 goto out;
282
283 buf[count] = '\0';
284 input_string = strstrip(buf);
285
286 /*
287 * Clear all breakpoints if:
288 * 1: echo > ksym_trace_filter
289 * 2: echo 0 > ksym_trace_filter
290 * 3: echo "*:---" > ksym_trace_filter
291 */
292 if (!input_string[0] || !strcmp(input_string, "0") ||
293 !strcmp(input_string, "*:---")) {
294 __ksym_trace_reset();
295 ret = 0;
296 goto out;
297 }
298
299 ret = op = parse_ksym_trace_str(input_string, &ksymname, &ksym_addr);
300 if (ret < 0)
301 goto out;
302
303 mutex_lock(&ksym_tracer_mutex);
304
305 ret = -EINVAL;
306 hlist_for_each_entry(entry, node, &ksym_filter_head, ksym_hlist) {
307 if (entry->attr.bp_addr == ksym_addr) {
308 /* Check for malformed request: (6) */
309 if (entry->attr.bp_type != op)
310 changed = 1;
311 else
312 goto out_unlock;
313 break;
314 }
315 }
316 if (changed) {
317 unregister_wide_hw_breakpoint(entry->ksym_hbp);
318 entry->attr.bp_type = op;
319 ret = 0;
320 if (op > 0) {
321 entry->ksym_hbp =
322 register_wide_hw_breakpoint(&entry->attr,
323 ksym_hbp_handler);
324 if (IS_ERR(entry->ksym_hbp))
325 ret = PTR_ERR(entry->ksym_hbp);
326 else
327 goto out_unlock;
328 }
329 /* Error or "symbol:---" case: drop it */
330 hlist_del_rcu(&(entry->ksym_hlist));
331 synchronize_rcu();
332 kfree(entry);
333 goto out_unlock;
334 } else {
335 /* Check for malformed request: (4) */
336 if (op)
337 ret = process_new_ksym_entry(ksymname, op, ksym_addr);
338 }
339out_unlock:
340 mutex_unlock(&ksym_tracer_mutex);
341out:
342 kfree(buf);
343 return !ret ? count : ret;
344}
345
346static const struct file_operations ksym_tracing_fops = {
347 .open = tracing_open_generic,
348 .read = ksym_trace_filter_read,
349 .write = ksym_trace_filter_write,
350};
351
352static void ksym_trace_reset(struct trace_array *tr)
353{
354 ksym_tracing_enabled = 0;
355 __ksym_trace_reset();
356}
357
358static int ksym_trace_init(struct trace_array *tr)
359{
360 int cpu, ret = 0;
361
362 for_each_online_cpu(cpu)
363 tracing_reset(tr, cpu);
364 ksym_tracing_enabled = 1;
365 ksym_trace_array = tr;
366
367 return ret;
368}
369
370static void ksym_trace_print_header(struct seq_file *m)
371{
372 seq_puts(m,
373 "# TASK-PID CPU# Symbol "
374 "Type Function\n");
375 seq_puts(m,
376 "# | | | "
377 " | |\n");
378}
379
380static enum print_line_t ksym_trace_output(struct trace_iterator *iter)
381{
382 struct trace_entry *entry = iter->ent;
383 struct trace_seq *s = &iter->seq;
384 struct ksym_trace_entry *field;
385 char str[KSYM_SYMBOL_LEN];
386 int ret;
387
388 if (entry->type != TRACE_KSYM)
389 return TRACE_TYPE_UNHANDLED;
390
391 trace_assign_type(field, entry);
392
393 ret = trace_seq_printf(s, "%11s-%-5d [%03d] %pS", field->cmd,
394 entry->pid, iter->cpu, (char *)field->addr);
395 if (!ret)
396 return TRACE_TYPE_PARTIAL_LINE;
397
398 switch (field->type) {
399 case HW_BREAKPOINT_R:
400 ret = trace_seq_printf(s, " R ");
401 break;
402 case HW_BREAKPOINT_W:
403 ret = trace_seq_printf(s, " W ");
404 break;
405 case HW_BREAKPOINT_R | HW_BREAKPOINT_W:
406 ret = trace_seq_printf(s, " RW ");
407 break;
408 default:
409 return TRACE_TYPE_PARTIAL_LINE;
410 }
411
412 if (!ret)
413 return TRACE_TYPE_PARTIAL_LINE;
414
415 sprint_symbol(str, field->ip);
416 ret = trace_seq_printf(s, "%s\n", str);
417 if (!ret)
418 return TRACE_TYPE_PARTIAL_LINE;
419
420 return TRACE_TYPE_HANDLED;
421}
422
423struct tracer ksym_tracer __read_mostly =
424{
425 .name = "ksym_tracer",
426 .init = ksym_trace_init,
427 .reset = ksym_trace_reset,
428#ifdef CONFIG_FTRACE_SELFTEST
429 .selftest = trace_selftest_startup_ksym,
430#endif
431 .print_header = ksym_trace_print_header,
432 .print_line = ksym_trace_output
433};
434
435#ifdef CONFIG_PROFILE_KSYM_TRACER
436static int ksym_profile_show(struct seq_file *m, void *v)
437{
438 struct hlist_node *node;
439 struct trace_ksym *entry;
440 int access_type = 0;
441 char fn_name[KSYM_NAME_LEN];
442
443 seq_puts(m, " Access Type ");
444 seq_puts(m, " Symbol Counter\n");
445 seq_puts(m, " ----------- ");
446 seq_puts(m, " ------ -------\n");
447
448 rcu_read_lock();
449 hlist_for_each_entry_rcu(entry, node, &ksym_filter_head, ksym_hlist) {
450
451 access_type = entry->attr.bp_type;
452
453 switch (access_type) {
454 case HW_BREAKPOINT_R:
455 seq_puts(m, " R ");
456 break;
457 case HW_BREAKPOINT_W:
458 seq_puts(m, " W ");
459 break;
460 case HW_BREAKPOINT_R | HW_BREAKPOINT_W:
461 seq_puts(m, " RW ");
462 break;
463 default:
464 seq_puts(m, " NA ");
465 }
466
467 if (lookup_symbol_name(entry->attr.bp_addr, fn_name) >= 0)
468 seq_printf(m, " %-36s", fn_name);
469 else
470 seq_printf(m, " %-36s", "<NA>");
471 seq_printf(m, " %15llu\n",
472 (unsigned long long)atomic64_read(&entry->counter));
473 }
474 rcu_read_unlock();
475
476 return 0;
477}
478
479static int ksym_profile_open(struct inode *node, struct file *file)
480{
481 return single_open(file, ksym_profile_show, NULL);
482}
483
484static const struct file_operations ksym_profile_fops = {
485 .open = ksym_profile_open,
486 .read = seq_read,
487 .llseek = seq_lseek,
488 .release = single_release,
489};
490#endif /* CONFIG_PROFILE_KSYM_TRACER */
491
492__init static int init_ksym_trace(void)
493{
494 struct dentry *d_tracer;
495
496 d_tracer = tracing_init_dentry();
497
498 trace_create_file("ksym_trace_filter", 0644, d_tracer,
499 NULL, &ksym_tracing_fops);
500
501#ifdef CONFIG_PROFILE_KSYM_TRACER
502 trace_create_file("ksym_profile", 0444, d_tracer,
503 NULL, &ksym_profile_fops);
504#endif
505
506 return register_tracer(&ksym_tracer);
507}
508device_initcall(init_ksym_trace);
generated by cgit v1.2.2 (git 2.25.0) at 2026-01-02 03:29:59 -0500