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authorFrederic Weisbecker <fweisbec@gmail.com>2010-07-15 17:27:35 -0400
committerFrederic Weisbecker <fweisbec@gmail.com>2010-07-15 17:59:33 -0400
commit5d550467b9770042e9699690907babc32104a8d4 (patch)
treeeda923f5976f5d6f881719998207696147cffa41 /kernel/trace/trace_ksym.c
parent86a8c63f75a4582c44465e2bf71bc2df175cee77 (diff)
tracing: Remove ksym tracer
The ksym (breakpoint) ftrace plugin has been superseded by perf tools that are much more poweful to use the cpu breakpoints. This tracer doesn't bring more feature. It has been deprecated for a while now, lets remove it. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Prasad <prasad@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/trace/trace_ksym.c')
-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 2025-09-20 07:19:38 -0400