ftrace: Fix regression where ftrace breaks when modules are loaded
[linux-2.6.git] / kernel / trace / trace_mmiotrace.c
1 /*
2  * Memory mapped I/O tracing
3  *
4  * Copyright (C) 2008 Pekka Paalanen <pq@iki.fi>
5  */
6
7 #define DEBUG 1
8
9 #include <linux/kernel.h>
10 #include <linux/mmiotrace.h>
11 #include <linux/pci.h>
12 #include <linux/slab.h>
13 #include <linux/time.h>
14
15 #include <asm/atomic.h>
16
17 #include "trace.h"
18 #include "trace_output.h"
19
20 struct header_iter {
21         struct pci_dev *dev;
22 };
23
24 static struct trace_array *mmio_trace_array;
25 static bool overrun_detected;
26 static unsigned long prev_overruns;
27 static atomic_t dropped_count;
28
29 static void mmio_reset_data(struct trace_array *tr)
30 {
31         overrun_detected = false;
32         prev_overruns = 0;
33
34         tracing_reset_online_cpus(tr);
35 }
36
37 static int mmio_trace_init(struct trace_array *tr)
38 {
39         pr_debug("in %s\n", __func__);
40         mmio_trace_array = tr;
41
42         mmio_reset_data(tr);
43         enable_mmiotrace();
44         return 0;
45 }
46
47 static void mmio_trace_reset(struct trace_array *tr)
48 {
49         pr_debug("in %s\n", __func__);
50
51         disable_mmiotrace();
52         mmio_reset_data(tr);
53         mmio_trace_array = NULL;
54 }
55
56 static void mmio_trace_start(struct trace_array *tr)
57 {
58         pr_debug("in %s\n", __func__);
59         mmio_reset_data(tr);
60 }
61
62 static int mmio_print_pcidev(struct trace_seq *s, const struct pci_dev *dev)
63 {
64         int ret = 0;
65         int i;
66         resource_size_t start, end;
67         const struct pci_driver *drv = pci_dev_driver(dev);
68
69         /* XXX: incomplete checks for trace_seq_printf() return value */
70         ret += trace_seq_printf(s, "PCIDEV %02x%02x %04x%04x %x",
71                                 dev->bus->number, dev->devfn,
72                                 dev->vendor, dev->device, dev->irq);
73         /*
74          * XXX: is pci_resource_to_user() appropriate, since we are
75          * supposed to interpret the __ioremap() phys_addr argument based on
76          * these printed values?
77          */
78         for (i = 0; i < 7; i++) {
79                 pci_resource_to_user(dev, i, &dev->resource[i], &start, &end);
80                 ret += trace_seq_printf(s, " %llx",
81                         (unsigned long long)(start |
82                         (dev->resource[i].flags & PCI_REGION_FLAG_MASK)));
83         }
84         for (i = 0; i < 7; i++) {
85                 pci_resource_to_user(dev, i, &dev->resource[i], &start, &end);
86                 ret += trace_seq_printf(s, " %llx",
87                         dev->resource[i].start < dev->resource[i].end ?
88                         (unsigned long long)(end - start) + 1 : 0);
89         }
90         if (drv)
91                 ret += trace_seq_printf(s, " %s\n", drv->name);
92         else
93                 ret += trace_seq_printf(s, " \n");
94         return ret;
95 }
96
97 static void destroy_header_iter(struct header_iter *hiter)
98 {
99         if (!hiter)
100                 return;
101         pci_dev_put(hiter->dev);
102         kfree(hiter);
103 }
104
105 static void mmio_pipe_open(struct trace_iterator *iter)
106 {
107         struct header_iter *hiter;
108         struct trace_seq *s = &iter->seq;
109
110         trace_seq_printf(s, "VERSION 20070824\n");
111
112         hiter = kzalloc(sizeof(*hiter), GFP_KERNEL);
113         if (!hiter)
114                 return;
115
116         hiter->dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, NULL);
117         iter->private = hiter;
118 }
119
120 /* XXX: This is not called when the pipe is closed! */
121 static void mmio_close(struct trace_iterator *iter)
122 {
123         struct header_iter *hiter = iter->private;
124         destroy_header_iter(hiter);
125         iter->private = NULL;
126 }
127
128 static unsigned long count_overruns(struct trace_iterator *iter)
129 {
130         unsigned long cnt = atomic_xchg(&dropped_count, 0);
131         unsigned long over = ring_buffer_overruns(iter->tr->buffer);
132
133         if (over > prev_overruns)
134                 cnt += over - prev_overruns;
135         prev_overruns = over;
136         return cnt;
137 }
138
139 static ssize_t mmio_read(struct trace_iterator *iter, struct file *filp,
140                                 char __user *ubuf, size_t cnt, loff_t *ppos)
141 {
142         ssize_t ret;
143         struct header_iter *hiter = iter->private;
144         struct trace_seq *s = &iter->seq;
145         unsigned long n;
146
147         n = count_overruns(iter);
148         if (n) {
149                 /* XXX: This is later than where events were lost. */
150                 trace_seq_printf(s, "MARK 0.000000 Lost %lu events.\n", n);
151                 if (!overrun_detected)
152                         pr_warning("mmiotrace has lost events.\n");
153                 overrun_detected = true;
154                 goto print_out;
155         }
156
157         if (!hiter)
158                 return 0;
159
160         mmio_print_pcidev(s, hiter->dev);
161         hiter->dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, hiter->dev);
162
163         if (!hiter->dev) {
164                 destroy_header_iter(hiter);
165                 iter->private = NULL;
166         }
167
168 print_out:
169         ret = trace_seq_to_user(s, ubuf, cnt);
170         return (ret == -EBUSY) ? 0 : ret;
171 }
172
173 static enum print_line_t mmio_print_rw(struct trace_iterator *iter)
174 {
175         struct trace_entry *entry = iter->ent;
176         struct trace_mmiotrace_rw *field;
177         struct mmiotrace_rw *rw;
178         struct trace_seq *s     = &iter->seq;
179         unsigned long long t    = ns2usecs(iter->ts);
180         unsigned long usec_rem  = do_div(t, USEC_PER_SEC);
181         unsigned secs           = (unsigned long)t;
182         int ret = 1;
183
184         trace_assign_type(field, entry);
185         rw = &field->rw;
186
187         switch (rw->opcode) {
188         case MMIO_READ:
189                 ret = trace_seq_printf(s,
190                         "R %d %u.%06lu %d 0x%llx 0x%lx 0x%lx %d\n",
191                         rw->width, secs, usec_rem, rw->map_id,
192                         (unsigned long long)rw->phys,
193                         rw->value, rw->pc, 0);
194                 break;
195         case MMIO_WRITE:
196                 ret = trace_seq_printf(s,
197                         "W %d %u.%06lu %d 0x%llx 0x%lx 0x%lx %d\n",
198                         rw->width, secs, usec_rem, rw->map_id,
199                         (unsigned long long)rw->phys,
200                         rw->value, rw->pc, 0);
201                 break;
202         case MMIO_UNKNOWN_OP:
203                 ret = trace_seq_printf(s,
204                         "UNKNOWN %u.%06lu %d 0x%llx %02lx,%02lx,"
205                         "%02lx 0x%lx %d\n",
206                         secs, usec_rem, rw->map_id,
207                         (unsigned long long)rw->phys,
208                         (rw->value >> 16) & 0xff, (rw->value >> 8) & 0xff,
209                         (rw->value >> 0) & 0xff, rw->pc, 0);
210                 break;
211         default:
212                 ret = trace_seq_printf(s, "rw what?\n");
213                 break;
214         }
215         if (ret)
216                 return TRACE_TYPE_HANDLED;
217         return TRACE_TYPE_PARTIAL_LINE;
218 }
219
220 static enum print_line_t mmio_print_map(struct trace_iterator *iter)
221 {
222         struct trace_entry *entry = iter->ent;
223         struct trace_mmiotrace_map *field;
224         struct mmiotrace_map *m;
225         struct trace_seq *s     = &iter->seq;
226         unsigned long long t    = ns2usecs(iter->ts);
227         unsigned long usec_rem  = do_div(t, USEC_PER_SEC);
228         unsigned secs           = (unsigned long)t;
229         int ret;
230
231         trace_assign_type(field, entry);
232         m = &field->map;
233
234         switch (m->opcode) {
235         case MMIO_PROBE:
236                 ret = trace_seq_printf(s,
237                         "MAP %u.%06lu %d 0x%llx 0x%lx 0x%lx 0x%lx %d\n",
238                         secs, usec_rem, m->map_id,
239                         (unsigned long long)m->phys, m->virt, m->len,
240                         0UL, 0);
241                 break;
242         case MMIO_UNPROBE:
243                 ret = trace_seq_printf(s,
244                         "UNMAP %u.%06lu %d 0x%lx %d\n",
245                         secs, usec_rem, m->map_id, 0UL, 0);
246                 break;
247         default:
248                 ret = trace_seq_printf(s, "map what?\n");
249                 break;
250         }
251         if (ret)
252                 return TRACE_TYPE_HANDLED;
253         return TRACE_TYPE_PARTIAL_LINE;
254 }
255
256 static enum print_line_t mmio_print_mark(struct trace_iterator *iter)
257 {
258         struct trace_entry *entry = iter->ent;
259         struct print_entry *print = (struct print_entry *)entry;
260         const char *msg         = print->buf;
261         struct trace_seq *s     = &iter->seq;
262         unsigned long long t    = ns2usecs(iter->ts);
263         unsigned long usec_rem  = do_div(t, USEC_PER_SEC);
264         unsigned secs           = (unsigned long)t;
265         int ret;
266
267         /* The trailing newline must be in the message. */
268         ret = trace_seq_printf(s, "MARK %u.%06lu %s", secs, usec_rem, msg);
269         if (!ret)
270                 return TRACE_TYPE_PARTIAL_LINE;
271
272         return TRACE_TYPE_HANDLED;
273 }
274
275 static enum print_line_t mmio_print_line(struct trace_iterator *iter)
276 {
277         switch (iter->ent->type) {
278         case TRACE_MMIO_RW:
279                 return mmio_print_rw(iter);
280         case TRACE_MMIO_MAP:
281                 return mmio_print_map(iter);
282         case TRACE_PRINT:
283                 return mmio_print_mark(iter);
284         default:
285                 return TRACE_TYPE_HANDLED; /* ignore unknown entries */
286         }
287 }
288
289 static struct tracer mmio_tracer __read_mostly =
290 {
291         .name           = "mmiotrace",
292         .init           = mmio_trace_init,
293         .reset          = mmio_trace_reset,
294         .start          = mmio_trace_start,
295         .pipe_open      = mmio_pipe_open,
296         .close          = mmio_close,
297         .read           = mmio_read,
298         .print_line     = mmio_print_line,
299 };
300
301 __init static int init_mmio_trace(void)
302 {
303         return register_tracer(&mmio_tracer);
304 }
305 device_initcall(init_mmio_trace);
306
307 static void __trace_mmiotrace_rw(struct trace_array *tr,
308                                 struct trace_array_cpu *data,
309                                 struct mmiotrace_rw *rw)
310 {
311         struct ftrace_event_call *call = &event_mmiotrace_rw;
312         struct ring_buffer *buffer = tr->buffer;
313         struct ring_buffer_event *event;
314         struct trace_mmiotrace_rw *entry;
315         int pc = preempt_count();
316
317         event = trace_buffer_lock_reserve(buffer, TRACE_MMIO_RW,
318                                           sizeof(*entry), 0, pc);
319         if (!event) {
320                 atomic_inc(&dropped_count);
321                 return;
322         }
323         entry   = ring_buffer_event_data(event);
324         entry->rw                       = *rw;
325
326         if (!filter_check_discard(call, entry, buffer, event))
327                 trace_buffer_unlock_commit(buffer, event, 0, pc);
328 }
329
330 void mmio_trace_rw(struct mmiotrace_rw *rw)
331 {
332         struct trace_array *tr = mmio_trace_array;
333         struct trace_array_cpu *data = tr->data[smp_processor_id()];
334         __trace_mmiotrace_rw(tr, data, rw);
335 }
336
337 static void __trace_mmiotrace_map(struct trace_array *tr,
338                                 struct trace_array_cpu *data,
339                                 struct mmiotrace_map *map)
340 {
341         struct ftrace_event_call *call = &event_mmiotrace_map;
342         struct ring_buffer *buffer = tr->buffer;
343         struct ring_buffer_event *event;
344         struct trace_mmiotrace_map *entry;
345         int pc = preempt_count();
346
347         event = trace_buffer_lock_reserve(buffer, TRACE_MMIO_MAP,
348                                           sizeof(*entry), 0, pc);
349         if (!event) {
350                 atomic_inc(&dropped_count);
351                 return;
352         }
353         entry   = ring_buffer_event_data(event);
354         entry->map                      = *map;
355
356         if (!filter_check_discard(call, entry, buffer, event))
357                 trace_buffer_unlock_commit(buffer, event, 0, pc);
358 }
359
360 void mmio_trace_mapping(struct mmiotrace_map *map)
361 {
362         struct trace_array *tr = mmio_trace_array;
363         struct trace_array_cpu *data;
364
365         preempt_disable();
366         data = tr->data[smp_processor_id()];
367         __trace_mmiotrace_map(tr, data, map);
368         preempt_enable();
369 }
370
371 int mmio_trace_printk(const char *fmt, va_list args)
372 {
373         return trace_vprintk(0, fmt, args);
374 }