Root/kernel/trace/trace_syscalls.c

1#include <trace/syscall.h>
2#include <trace/events/syscalls.h>
3#include <linux/slab.h>
4#include <linux/kernel.h>
5#include <linux/ftrace.h>
6#include <linux/perf_event.h>
7#include <asm/syscall.h>
8
9#include "trace_output.h"
10#include "trace.h"
11
12static DEFINE_MUTEX(syscall_trace_lock);
13static int sys_refcount_enter;
14static int sys_refcount_exit;
15static DECLARE_BITMAP(enabled_enter_syscalls, NR_syscalls);
16static DECLARE_BITMAP(enabled_exit_syscalls, NR_syscalls);
17
18static int syscall_enter_register(struct ftrace_event_call *event,
19                 enum trace_reg type);
20static int syscall_exit_register(struct ftrace_event_call *event,
21                 enum trace_reg type);
22
23static int syscall_enter_define_fields(struct ftrace_event_call *call);
24static int syscall_exit_define_fields(struct ftrace_event_call *call);
25
26static struct list_head *
27syscall_get_enter_fields(struct ftrace_event_call *call)
28{
29    struct syscall_metadata *entry = call->data;
30
31    return &entry->enter_fields;
32}
33
34struct trace_event_functions enter_syscall_print_funcs = {
35    .trace = print_syscall_enter,
36};
37
38struct trace_event_functions exit_syscall_print_funcs = {
39    .trace = print_syscall_exit,
40};
41
42struct ftrace_event_class event_class_syscall_enter = {
43    .system = "syscalls",
44    .reg = syscall_enter_register,
45    .define_fields = syscall_enter_define_fields,
46    .get_fields = syscall_get_enter_fields,
47    .raw_init = init_syscall_trace,
48};
49
50struct ftrace_event_class event_class_syscall_exit = {
51    .system = "syscalls",
52    .reg = syscall_exit_register,
53    .define_fields = syscall_exit_define_fields,
54    .fields = LIST_HEAD_INIT(event_class_syscall_exit.fields),
55    .raw_init = init_syscall_trace,
56};
57
58extern struct syscall_metadata *__start_syscalls_metadata[];
59extern struct syscall_metadata *__stop_syscalls_metadata[];
60
61static struct syscall_metadata **syscalls_metadata;
62
63static __init struct syscall_metadata *
64find_syscall_meta(unsigned long syscall)
65{
66    struct syscall_metadata **start;
67    struct syscall_metadata **stop;
68    char str[KSYM_SYMBOL_LEN];
69
70
71    start = __start_syscalls_metadata;
72    stop = __stop_syscalls_metadata;
73    kallsyms_lookup(syscall, NULL, NULL, NULL, str);
74
75    for ( ; start < stop; start++) {
76        /*
77         * Only compare after the "sys" prefix. Archs that use
78         * syscall wrappers may have syscalls symbols aliases prefixed
79         * with "SyS" instead of "sys", leading to an unwanted
80         * mismatch.
81         */
82        if ((*start)->name && !strcmp((*start)->name + 3, str + 3))
83            return *start;
84    }
85    return NULL;
86}
87
88static struct syscall_metadata *syscall_nr_to_meta(int nr)
89{
90    if (!syscalls_metadata || nr >= NR_syscalls || nr < 0)
91        return NULL;
92
93    return syscalls_metadata[nr];
94}
95
96enum print_line_t
97print_syscall_enter(struct trace_iterator *iter, int flags,
98            struct trace_event *event)
99{
100    struct trace_seq *s = &iter->seq;
101    struct trace_entry *ent = iter->ent;
102    struct syscall_trace_enter *trace;
103    struct syscall_metadata *entry;
104    int i, ret, syscall;
105
106    trace = (typeof(trace))ent;
107    syscall = trace->nr;
108    entry = syscall_nr_to_meta(syscall);
109
110    if (!entry)
111        goto end;
112
113    if (entry->enter_event->event.type != ent->type) {
114        WARN_ON_ONCE(1);
115        goto end;
116    }
117
118    ret = trace_seq_printf(s, "%s(", entry->name);
119    if (!ret)
120        return TRACE_TYPE_PARTIAL_LINE;
121
122    for (i = 0; i < entry->nb_args; i++) {
123        /* parameter types */
124        if (trace_flags & TRACE_ITER_VERBOSE) {
125            ret = trace_seq_printf(s, "%s ", entry->types[i]);
126            if (!ret)
127                return TRACE_TYPE_PARTIAL_LINE;
128        }
129        /* parameter values */
130        ret = trace_seq_printf(s, "%s: %lx%s", entry->args[i],
131                       trace->args[i],
132                       i == entry->nb_args - 1 ? "" : ", ");
133        if (!ret)
134            return TRACE_TYPE_PARTIAL_LINE;
135    }
136
137    ret = trace_seq_putc(s, ')');
138    if (!ret)
139        return TRACE_TYPE_PARTIAL_LINE;
140
141end:
142    ret = trace_seq_putc(s, '\n');
143    if (!ret)
144        return TRACE_TYPE_PARTIAL_LINE;
145
146    return TRACE_TYPE_HANDLED;
147}
148
149enum print_line_t
150print_syscall_exit(struct trace_iterator *iter, int flags,
151           struct trace_event *event)
152{
153    struct trace_seq *s = &iter->seq;
154    struct trace_entry *ent = iter->ent;
155    struct syscall_trace_exit *trace;
156    int syscall;
157    struct syscall_metadata *entry;
158    int ret;
159
160    trace = (typeof(trace))ent;
161    syscall = trace->nr;
162    entry = syscall_nr_to_meta(syscall);
163
164    if (!entry) {
165        trace_seq_printf(s, "\n");
166        return TRACE_TYPE_HANDLED;
167    }
168
169    if (entry->exit_event->event.type != ent->type) {
170        WARN_ON_ONCE(1);
171        return TRACE_TYPE_UNHANDLED;
172    }
173
174    ret = trace_seq_printf(s, "%s -> 0x%lx\n", entry->name,
175                trace->ret);
176    if (!ret)
177        return TRACE_TYPE_PARTIAL_LINE;
178
179    return TRACE_TYPE_HANDLED;
180}
181
182extern char *__bad_type_size(void);
183
184#define SYSCALL_FIELD(type, name) \
185    sizeof(type) != sizeof(trace.name) ? \
186        __bad_type_size() : \
187        #type, #name, offsetof(typeof(trace), name), \
188        sizeof(trace.name), is_signed_type(type)
189
190static
191int __set_enter_print_fmt(struct syscall_metadata *entry, char *buf, int len)
192{
193    int i;
194    int pos = 0;
195
196    /* When len=0, we just calculate the needed length */
197#define LEN_OR_ZERO (len ? len - pos : 0)
198
199    pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
200    for (i = 0; i < entry->nb_args; i++) {
201        pos += snprintf(buf + pos, LEN_OR_ZERO, "%s: 0x%%0%zulx%s",
202                entry->args[i], sizeof(unsigned long),
203                i == entry->nb_args - 1 ? "" : ", ");
204    }
205    pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
206
207    for (i = 0; i < entry->nb_args; i++) {
208        pos += snprintf(buf + pos, LEN_OR_ZERO,
209                ", ((unsigned long)(REC->%s))", entry->args[i]);
210    }
211
212#undef LEN_OR_ZERO
213
214    /* return the length of print_fmt */
215    return pos;
216}
217
218static int set_syscall_print_fmt(struct ftrace_event_call *call)
219{
220    char *print_fmt;
221    int len;
222    struct syscall_metadata *entry = call->data;
223
224    if (entry->enter_event != call) {
225        call->print_fmt = "\"0x%lx\", REC->ret";
226        return 0;
227    }
228
229    /* First: called with 0 length to calculate the needed length */
230    len = __set_enter_print_fmt(entry, NULL, 0);
231
232    print_fmt = kmalloc(len + 1, GFP_KERNEL);
233    if (!print_fmt)
234        return -ENOMEM;
235
236    /* Second: actually write the @print_fmt */
237    __set_enter_print_fmt(entry, print_fmt, len + 1);
238    call->print_fmt = print_fmt;
239
240    return 0;
241}
242
243static void free_syscall_print_fmt(struct ftrace_event_call *call)
244{
245    struct syscall_metadata *entry = call->data;
246
247    if (entry->enter_event == call)
248        kfree(call->print_fmt);
249}
250
251static int syscall_enter_define_fields(struct ftrace_event_call *call)
252{
253    struct syscall_trace_enter trace;
254    struct syscall_metadata *meta = call->data;
255    int ret;
256    int i;
257    int offset = offsetof(typeof(trace), args);
258
259    ret = trace_define_field(call, SYSCALL_FIELD(int, nr), FILTER_OTHER);
260    if (ret)
261        return ret;
262
263    for (i = 0; i < meta->nb_args; i++) {
264        ret = trace_define_field(call, meta->types[i],
265                     meta->args[i], offset,
266                     sizeof(unsigned long), 0,
267                     FILTER_OTHER);
268        offset += sizeof(unsigned long);
269    }
270
271    return ret;
272}
273
274static int syscall_exit_define_fields(struct ftrace_event_call *call)
275{
276    struct syscall_trace_exit trace;
277    int ret;
278
279    ret = trace_define_field(call, SYSCALL_FIELD(int, nr), FILTER_OTHER);
280    if (ret)
281        return ret;
282
283    ret = trace_define_field(call, SYSCALL_FIELD(long, ret),
284                 FILTER_OTHER);
285
286    return ret;
287}
288
289void ftrace_syscall_enter(void *ignore, struct pt_regs *regs, long id)
290{
291    struct syscall_trace_enter *entry;
292    struct syscall_metadata *sys_data;
293    struct ring_buffer_event *event;
294    struct ring_buffer *buffer;
295    int size;
296    int syscall_nr;
297
298    syscall_nr = syscall_get_nr(current, regs);
299    if (syscall_nr < 0)
300        return;
301    if (!test_bit(syscall_nr, enabled_enter_syscalls))
302        return;
303
304    sys_data = syscall_nr_to_meta(syscall_nr);
305    if (!sys_data)
306        return;
307
308    size = sizeof(*entry) + sizeof(unsigned long) * sys_data->nb_args;
309
310    event = trace_current_buffer_lock_reserve(&buffer,
311            sys_data->enter_event->event.type, size, 0, 0);
312    if (!event)
313        return;
314
315    entry = ring_buffer_event_data(event);
316    entry->nr = syscall_nr;
317    syscall_get_arguments(current, regs, 0, sys_data->nb_args, entry->args);
318
319    if (!filter_current_check_discard(buffer, sys_data->enter_event,
320                      entry, event))
321        trace_current_buffer_unlock_commit(buffer, event, 0, 0);
322}
323
324void ftrace_syscall_exit(void *ignore, struct pt_regs *regs, long ret)
325{
326    struct syscall_trace_exit *entry;
327    struct syscall_metadata *sys_data;
328    struct ring_buffer_event *event;
329    struct ring_buffer *buffer;
330    int syscall_nr;
331
332    syscall_nr = syscall_get_nr(current, regs);
333    if (syscall_nr < 0)
334        return;
335    if (!test_bit(syscall_nr, enabled_exit_syscalls))
336        return;
337
338    sys_data = syscall_nr_to_meta(syscall_nr);
339    if (!sys_data)
340        return;
341
342    event = trace_current_buffer_lock_reserve(&buffer,
343            sys_data->exit_event->event.type, sizeof(*entry), 0, 0);
344    if (!event)
345        return;
346
347    entry = ring_buffer_event_data(event);
348    entry->nr = syscall_nr;
349    entry->ret = syscall_get_return_value(current, regs);
350
351    if (!filter_current_check_discard(buffer, sys_data->exit_event,
352                      entry, event))
353        trace_current_buffer_unlock_commit(buffer, event, 0, 0);
354}
355
356int reg_event_syscall_enter(struct ftrace_event_call *call)
357{
358    int ret = 0;
359    int num;
360
361    num = ((struct syscall_metadata *)call->data)->syscall_nr;
362    if (num < 0 || num >= NR_syscalls)
363        return -ENOSYS;
364    mutex_lock(&syscall_trace_lock);
365    if (!sys_refcount_enter)
366        ret = register_trace_sys_enter(ftrace_syscall_enter, NULL);
367    if (!ret) {
368        set_bit(num, enabled_enter_syscalls);
369        sys_refcount_enter++;
370    }
371    mutex_unlock(&syscall_trace_lock);
372    return ret;
373}
374
375void unreg_event_syscall_enter(struct ftrace_event_call *call)
376{
377    int num;
378
379    num = ((struct syscall_metadata *)call->data)->syscall_nr;
380    if (num < 0 || num >= NR_syscalls)
381        return;
382    mutex_lock(&syscall_trace_lock);
383    sys_refcount_enter--;
384    clear_bit(num, enabled_enter_syscalls);
385    if (!sys_refcount_enter)
386        unregister_trace_sys_enter(ftrace_syscall_enter, NULL);
387    mutex_unlock(&syscall_trace_lock);
388}
389
390int reg_event_syscall_exit(struct ftrace_event_call *call)
391{
392    int ret = 0;
393    int num;
394
395    num = ((struct syscall_metadata *)call->data)->syscall_nr;
396    if (num < 0 || num >= NR_syscalls)
397        return -ENOSYS;
398    mutex_lock(&syscall_trace_lock);
399    if (!sys_refcount_exit)
400        ret = register_trace_sys_exit(ftrace_syscall_exit, NULL);
401    if (!ret) {
402        set_bit(num, enabled_exit_syscalls);
403        sys_refcount_exit++;
404    }
405    mutex_unlock(&syscall_trace_lock);
406    return ret;
407}
408
409void unreg_event_syscall_exit(struct ftrace_event_call *call)
410{
411    int num;
412
413    num = ((struct syscall_metadata *)call->data)->syscall_nr;
414    if (num < 0 || num >= NR_syscalls)
415        return;
416    mutex_lock(&syscall_trace_lock);
417    sys_refcount_exit--;
418    clear_bit(num, enabled_exit_syscalls);
419    if (!sys_refcount_exit)
420        unregister_trace_sys_exit(ftrace_syscall_exit, NULL);
421    mutex_unlock(&syscall_trace_lock);
422}
423
424int init_syscall_trace(struct ftrace_event_call *call)
425{
426    int id;
427
428    if (set_syscall_print_fmt(call) < 0)
429        return -ENOMEM;
430
431    id = trace_event_raw_init(call);
432
433    if (id < 0) {
434        free_syscall_print_fmt(call);
435        return id;
436    }
437
438    return id;
439}
440
441unsigned long __init arch_syscall_addr(int nr)
442{
443    return (unsigned long)sys_call_table[nr];
444}
445
446int __init init_ftrace_syscalls(void)
447{
448    struct syscall_metadata *meta;
449    unsigned long addr;
450    int i;
451
452    syscalls_metadata = kzalloc(sizeof(*syscalls_metadata) *
453                    NR_syscalls, GFP_KERNEL);
454    if (!syscalls_metadata) {
455        WARN_ON(1);
456        return -ENOMEM;
457    }
458
459    for (i = 0; i < NR_syscalls; i++) {
460        addr = arch_syscall_addr(i);
461        meta = find_syscall_meta(addr);
462        if (!meta)
463            continue;
464
465        meta->syscall_nr = i;
466        syscalls_metadata[i] = meta;
467    }
468
469    return 0;
470}
471core_initcall(init_ftrace_syscalls);
472
473#ifdef CONFIG_PERF_EVENTS
474
475static DECLARE_BITMAP(enabled_perf_enter_syscalls, NR_syscalls);
476static DECLARE_BITMAP(enabled_perf_exit_syscalls, NR_syscalls);
477static int sys_perf_refcount_enter;
478static int sys_perf_refcount_exit;
479
480static void perf_syscall_enter(void *ignore, struct pt_regs *regs, long id)
481{
482    struct syscall_metadata *sys_data;
483    struct syscall_trace_enter *rec;
484    struct hlist_head *head;
485    int syscall_nr;
486    int rctx;
487    int size;
488
489    syscall_nr = syscall_get_nr(current, regs);
490    if (!test_bit(syscall_nr, enabled_perf_enter_syscalls))
491        return;
492
493    sys_data = syscall_nr_to_meta(syscall_nr);
494    if (!sys_data)
495        return;
496
497    /* get the size after alignment with the u32 buffer size field */
498    size = sizeof(unsigned long) * sys_data->nb_args + sizeof(*rec);
499    size = ALIGN(size + sizeof(u32), sizeof(u64));
500    size -= sizeof(u32);
501
502    if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
503              "perf buffer not large enough"))
504        return;
505
506    rec = (struct syscall_trace_enter *)perf_trace_buf_prepare(size,
507                sys_data->enter_event->event.type, regs, &rctx);
508    if (!rec)
509        return;
510
511    rec->nr = syscall_nr;
512    syscall_get_arguments(current, regs, 0, sys_data->nb_args,
513                   (unsigned long *)&rec->args);
514
515    head = this_cpu_ptr(sys_data->enter_event->perf_events);
516    perf_trace_buf_submit(rec, size, rctx, 0, 1, regs, head);
517}
518
519int perf_sysenter_enable(struct ftrace_event_call *call)
520{
521    int ret = 0;
522    int num;
523
524    num = ((struct syscall_metadata *)call->data)->syscall_nr;
525
526    mutex_lock(&syscall_trace_lock);
527    if (!sys_perf_refcount_enter)
528        ret = register_trace_sys_enter(perf_syscall_enter, NULL);
529    if (ret) {
530        pr_info("event trace: Could not activate"
531                "syscall entry trace point");
532    } else {
533        set_bit(num, enabled_perf_enter_syscalls);
534        sys_perf_refcount_enter++;
535    }
536    mutex_unlock(&syscall_trace_lock);
537    return ret;
538}
539
540void perf_sysenter_disable(struct ftrace_event_call *call)
541{
542    int num;
543
544    num = ((struct syscall_metadata *)call->data)->syscall_nr;
545
546    mutex_lock(&syscall_trace_lock);
547    sys_perf_refcount_enter--;
548    clear_bit(num, enabled_perf_enter_syscalls);
549    if (!sys_perf_refcount_enter)
550        unregister_trace_sys_enter(perf_syscall_enter, NULL);
551    mutex_unlock(&syscall_trace_lock);
552}
553
554static void perf_syscall_exit(void *ignore, struct pt_regs *regs, long ret)
555{
556    struct syscall_metadata *sys_data;
557    struct syscall_trace_exit *rec;
558    struct hlist_head *head;
559    int syscall_nr;
560    int rctx;
561    int size;
562
563    syscall_nr = syscall_get_nr(current, regs);
564    if (!test_bit(syscall_nr, enabled_perf_exit_syscalls))
565        return;
566
567    sys_data = syscall_nr_to_meta(syscall_nr);
568    if (!sys_data)
569        return;
570
571    /* We can probably do that at build time */
572    size = ALIGN(sizeof(*rec) + sizeof(u32), sizeof(u64));
573    size -= sizeof(u32);
574
575    /*
576     * Impossible, but be paranoid with the future
577     * How to put this check outside runtime?
578     */
579    if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
580        "exit event has grown above perf buffer size"))
581        return;
582
583    rec = (struct syscall_trace_exit *)perf_trace_buf_prepare(size,
584                sys_data->exit_event->event.type, regs, &rctx);
585    if (!rec)
586        return;
587
588    rec->nr = syscall_nr;
589    rec->ret = syscall_get_return_value(current, regs);
590
591    head = this_cpu_ptr(sys_data->exit_event->perf_events);
592    perf_trace_buf_submit(rec, size, rctx, 0, 1, regs, head);
593}
594
595int perf_sysexit_enable(struct ftrace_event_call *call)
596{
597    int ret = 0;
598    int num;
599
600    num = ((struct syscall_metadata *)call->data)->syscall_nr;
601
602    mutex_lock(&syscall_trace_lock);
603    if (!sys_perf_refcount_exit)
604        ret = register_trace_sys_exit(perf_syscall_exit, NULL);
605    if (ret) {
606        pr_info("event trace: Could not activate"
607                "syscall exit trace point");
608    } else {
609        set_bit(num, enabled_perf_exit_syscalls);
610        sys_perf_refcount_exit++;
611    }
612    mutex_unlock(&syscall_trace_lock);
613    return ret;
614}
615
616void perf_sysexit_disable(struct ftrace_event_call *call)
617{
618    int num;
619
620    num = ((struct syscall_metadata *)call->data)->syscall_nr;
621
622    mutex_lock(&syscall_trace_lock);
623    sys_perf_refcount_exit--;
624    clear_bit(num, enabled_perf_exit_syscalls);
625    if (!sys_perf_refcount_exit)
626        unregister_trace_sys_exit(perf_syscall_exit, NULL);
627    mutex_unlock(&syscall_trace_lock);
628}
629
630#endif /* CONFIG_PERF_EVENTS */
631
632static int syscall_enter_register(struct ftrace_event_call *event,
633                 enum trace_reg type)
634{
635    switch (type) {
636    case TRACE_REG_REGISTER:
637        return reg_event_syscall_enter(event);
638    case TRACE_REG_UNREGISTER:
639        unreg_event_syscall_enter(event);
640        return 0;
641
642#ifdef CONFIG_PERF_EVENTS
643    case TRACE_REG_PERF_REGISTER:
644        return perf_sysenter_enable(event);
645    case TRACE_REG_PERF_UNREGISTER:
646        perf_sysenter_disable(event);
647        return 0;
648#endif
649    }
650    return 0;
651}
652
653static int syscall_exit_register(struct ftrace_event_call *event,
654                 enum trace_reg type)
655{
656    switch (type) {
657    case TRACE_REG_REGISTER:
658        return reg_event_syscall_exit(event);
659    case TRACE_REG_UNREGISTER:
660        unreg_event_syscall_exit(event);
661        return 0;
662
663#ifdef CONFIG_PERF_EVENTS
664    case TRACE_REG_PERF_REGISTER:
665        return perf_sysexit_enable(event);
666    case TRACE_REG_PERF_UNREGISTER:
667        perf_sysexit_disable(event);
668        return 0;
669#endif
670    }
671    return 0;
672}
673

Archive Download this file

Branches:
ben-wpan
ben-wpan-stefan
javiroman/ks7010
jz-2.6.34
jz-2.6.34-rc5
jz-2.6.34-rc6
jz-2.6.34-rc7
jz-2.6.35
jz-2.6.36
jz-2.6.37
jz-2.6.38
jz-2.6.39
jz-3.0
jz-3.1
jz-3.11
jz-3.12
jz-3.13
jz-3.15
jz-3.16
jz-3.18-dt
jz-3.2
jz-3.3
jz-3.4
jz-3.5
jz-3.6
jz-3.6-rc2-pwm
jz-3.9
jz-3.9-clk
jz-3.9-rc8
jz47xx
jz47xx-2.6.38
master

Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9



interactive