1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Memory mapped I/O tracing
4 *
5 * Copyright (C) 2008 Pekka Paalanen <pq@iki.fi>
6 */
7
8#define DEBUG 1
9
10#include <linux/kernel.h>
11#include <linux/mmiotrace.h>
12#include <linux/pci.h>
13#include <linux/slab.h>
14#include <linux/time.h>
15
16#include <linux/atomic.h>
17
18#include "trace.h"
19#include "trace_output.h"
20
21struct header_iter {
22 struct pci_dev *dev;
23};
24
25static struct trace_array *mmio_trace_array;
26static bool overrun_detected;
27static unsigned long prev_overruns;
28static atomic_t dropped_count;
29
30static void mmio_reset_data(struct trace_array *tr)
31{
32 overrun_detected = false;
33 prev_overruns = 0;
34
35 tracing_reset_online_cpus(&tr->trace_buffer);
36}
37
38static int mmio_trace_init(struct trace_array *tr)
39{
40 pr_debug("in %s\n", __func__);
41 mmio_trace_array = tr;
42
43 mmio_reset_data(tr);
44 enable_mmiotrace();
45 return 0;
46}
47
48static void mmio_trace_reset(struct trace_array *tr)
49{
50 pr_debug("in %s\n", __func__);
51
52 disable_mmiotrace();
53 mmio_reset_data(tr);
54 mmio_trace_array = NULL;
55}
56
57static void mmio_trace_start(struct trace_array *tr)
58{
59 pr_debug("in %s\n", __func__);
60 mmio_reset_data(tr);
61}
62
63static void mmio_print_pcidev(struct trace_seq *s, const struct pci_dev *dev)
64{
65 int i;
66 resource_size_t start, end;
67 const struct pci_driver *drv = pci_dev_driver(dev);
68
69 trace_seq_printf(s, "PCIDEV %02x%02x %04x%04x %x",
70 dev->bus->number, dev->devfn,
71 dev->vendor, dev->device, dev->irq);
72 for (i = 0; i < 7; i++) {
73 start = dev->resource[i].start;
74 trace_seq_printf(s, " %llx",
75 (unsigned long long)(start |
76 (dev->resource[i].flags & PCI_REGION_FLAG_MASK)));
77 }
78 for (i = 0; i < 7; i++) {
79 start = dev->resource[i].start;
80 end = dev->resource[i].end;
81 trace_seq_printf(s, " %llx",
82 dev->resource[i].start < dev->resource[i].end ?
83 (unsigned long long)(end - start) + 1 : 0);
84 }
85 if (drv)
86 trace_seq_printf(s, " %s\n", drv->name);
87 else
88 trace_seq_puts(s, " \n");
89}
90
91static void destroy_header_iter(struct header_iter *hiter)
92{
93 if (!hiter)
94 return;
95 pci_dev_put(hiter->dev);
96 kfree(hiter);
97}
98
99static void mmio_pipe_open(struct trace_iterator *iter)
100{
101 struct header_iter *hiter;
102 struct trace_seq *s = &iter->seq;
103
104 trace_seq_puts(s, "VERSION 20070824\n");
105
106 hiter = kzalloc(sizeof(*hiter), GFP_KERNEL);
107 if (!hiter)
108 return;
109
110 hiter->dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, NULL);
111 iter->private = hiter;
112}
113
114/* XXX: This is not called when the pipe is closed! */
115static void mmio_close(struct trace_iterator *iter)
116{
117 struct header_iter *hiter = iter->private;
118 destroy_header_iter(hiter);
119 iter->private = NULL;
120}
121
122static unsigned long count_overruns(struct trace_iterator *iter)
123{
124 unsigned long cnt = atomic_xchg(&dropped_count, 0);
125 unsigned long over = ring_buffer_overruns(iter->trace_buffer->buffer);
126
127 if (over > prev_overruns)
128 cnt += over - prev_overruns;
129 prev_overruns = over;
130 return cnt;
131}
132
133static ssize_t mmio_read(struct trace_iterator *iter, struct file *filp,
134 char __user *ubuf, size_t cnt, loff_t *ppos)
135{
136 ssize_t ret;
137 struct header_iter *hiter = iter->private;
138 struct trace_seq *s = &iter->seq;
139 unsigned long n;
140
141 n = count_overruns(iter);
142 if (n) {
143 /* XXX: This is later than where events were lost. */
144 trace_seq_printf(s, "MARK 0.000000 Lost %lu events.\n", n);
145 if (!overrun_detected)
146 pr_warn("mmiotrace has lost events\n");
147 overrun_detected = true;
148 goto print_out;
149 }
150
151 if (!hiter)
152 return 0;
153
154 mmio_print_pcidev(s, hiter->dev);
155 hiter->dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, hiter->dev);
156
157 if (!hiter->dev) {
158 destroy_header_iter(hiter);
159 iter->private = NULL;
160 }
161
162print_out:
163 ret = trace_seq_to_user(s, ubuf, cnt);
164 return (ret == -EBUSY) ? 0 : ret;
165}
166
167static enum print_line_t mmio_print_rw(struct trace_iterator *iter)
168{
169 struct trace_entry *entry = iter->ent;
170 struct trace_mmiotrace_rw *field;
171 struct mmiotrace_rw *rw;
172 struct trace_seq *s = &iter->seq;
173 unsigned long long t = ns2usecs(iter->ts);
174 unsigned long usec_rem = do_div(t, USEC_PER_SEC);
175 unsigned secs = (unsigned long)t;
176
177 trace_assign_type(field, entry);
178 rw = &field->rw;
179
180 switch (rw->opcode) {
181 case MMIO_READ:
182 trace_seq_printf(s,
183 "R %d %u.%06lu %d 0x%llx 0x%lx 0x%lx %d\n",
184 rw->width, secs, usec_rem, rw->map_id,
185 (unsigned long long)rw->phys,
186 rw->value, rw->pc, 0);
187 break;
188 case MMIO_WRITE:
189 trace_seq_printf(s,
190 "W %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_UNKNOWN_OP:
196 trace_seq_printf(s,
197 "UNKNOWN %u.%06lu %d 0x%llx %02lx,%02lx,"
198 "%02lx 0x%lx %d\n",
199 secs, usec_rem, rw->map_id,
200 (unsigned long long)rw->phys,
201 (rw->value >> 16) & 0xff, (rw->value >> 8) & 0xff,
202 (rw->value >> 0) & 0xff, rw->pc, 0);
203 break;
204 default:
205 trace_seq_puts(s, "rw what?\n");
206 break;
207 }
208
209 return trace_handle_return(s);
210}
211
212static enum print_line_t mmio_print_map(struct trace_iterator *iter)
213{
214 struct trace_entry *entry = iter->ent;
215 struct trace_mmiotrace_map *field;
216 struct mmiotrace_map *m;
217 struct trace_seq *s = &iter->seq;
218 unsigned long long t = ns2usecs(iter->ts);
219 unsigned long usec_rem = do_div(t, USEC_PER_SEC);
220 unsigned secs = (unsigned long)t;
221
222 trace_assign_type(field, entry);
223 m = &field->map;
224
225 switch (m->opcode) {
226 case MMIO_PROBE:
227 trace_seq_printf(s,
228 "MAP %u.%06lu %d 0x%llx 0x%lx 0x%lx 0x%lx %d\n",
229 secs, usec_rem, m->map_id,
230 (unsigned long long)m->phys, m->virt, m->len,
231 0UL, 0);
232 break;
233 case MMIO_UNPROBE:
234 trace_seq_printf(s,
235 "UNMAP %u.%06lu %d 0x%lx %d\n",
236 secs, usec_rem, m->map_id, 0UL, 0);
237 break;
238 default:
239 trace_seq_puts(s, "map what?\n");
240 break;
241 }
242
243 return trace_handle_return(s);
244}
245
246static enum print_line_t mmio_print_mark(struct trace_iterator *iter)
247{
248 struct trace_entry *entry = iter->ent;
249 struct print_entry *print = (struct print_entry *)entry;
250 const char *msg = print->buf;
251 struct trace_seq *s = &iter->seq;
252 unsigned long long t = ns2usecs(iter->ts);
253 unsigned long usec_rem = do_div(t, USEC_PER_SEC);
254 unsigned secs = (unsigned long)t;
255
256 /* The trailing newline must be in the message. */
257 trace_seq_printf(s, "MARK %u.%06lu %s", secs, usec_rem, msg);
258
259 return trace_handle_return(s);
260}
261
262static enum print_line_t mmio_print_line(struct trace_iterator *iter)
263{
264 switch (iter->ent->type) {
265 case TRACE_MMIO_RW:
266 return mmio_print_rw(iter);
267 case TRACE_MMIO_MAP:
268 return mmio_print_map(iter);
269 case TRACE_PRINT:
270 return mmio_print_mark(iter);
271 default:
272 return TRACE_TYPE_HANDLED; /* ignore unknown entries */
273 }
274}
275
276static struct tracer mmio_tracer __read_mostly =
277{
278 .name = "mmiotrace",
279 .init = mmio_trace_init,
280 .reset = mmio_trace_reset,
281 .start = mmio_trace_start,
282 .pipe_open = mmio_pipe_open,
283 .close = mmio_close,
284 .read = mmio_read,
285 .print_line = mmio_print_line,
286 .noboot = true,
287};
288
289__init static int init_mmio_trace(void)
290{
291 return register_tracer(&mmio_tracer);
292}
293device_initcall(init_mmio_trace);
294
295static void __trace_mmiotrace_rw(struct trace_array *tr,
296 struct trace_array_cpu *data,
297 struct mmiotrace_rw *rw)
298{
299 struct trace_event_call *call = &event_mmiotrace_rw;
300 struct ring_buffer *buffer = tr->trace_buffer.buffer;
301 struct ring_buffer_event *event;
302 struct trace_mmiotrace_rw *entry;
303 int pc = preempt_count();
304
305 event = trace_buffer_lock_reserve(buffer, TRACE_MMIO_RW,
306 sizeof(*entry), 0, pc);
307 if (!event) {
308 atomic_inc(&dropped_count);
309 return;
310 }
311 entry = ring_buffer_event_data(event);
312 entry->rw = *rw;
313
314 if (!call_filter_check_discard(call, entry, buffer, event))
315 trace_buffer_unlock_commit(tr, buffer, event, 0, pc);
316}
317
318void mmio_trace_rw(struct mmiotrace_rw *rw)
319{
320 struct trace_array *tr = mmio_trace_array;
321 struct trace_array_cpu *data = per_cpu_ptr(tr->trace_buffer.data, smp_processor_id());
322 __trace_mmiotrace_rw(tr, data, rw);
323}
324
325static void __trace_mmiotrace_map(struct trace_array *tr,
326 struct trace_array_cpu *data,
327 struct mmiotrace_map *map)
328{
329 struct trace_event_call *call = &event_mmiotrace_map;
330 struct ring_buffer *buffer = tr->trace_buffer.buffer;
331 struct ring_buffer_event *event;
332 struct trace_mmiotrace_map *entry;
333 int pc = preempt_count();
334
335 event = trace_buffer_lock_reserve(buffer, TRACE_MMIO_MAP,
336 sizeof(*entry), 0, pc);
337 if (!event) {
338 atomic_inc(&dropped_count);
339 return;
340 }
341 entry = ring_buffer_event_data(event);
342 entry->map = *map;
343
344 if (!call_filter_check_discard(call, entry, buffer, event))
345 trace_buffer_unlock_commit(tr, buffer, event, 0, pc);
346}
347
348void mmio_trace_mapping(struct mmiotrace_map *map)
349{
350 struct trace_array *tr = mmio_trace_array;
351 struct trace_array_cpu *data;
352
353 preempt_disable();
354 data = per_cpu_ptr(tr->trace_buffer.data, smp_processor_id());
355 __trace_mmiotrace_map(tr, data, map);
356 preempt_enable();
357}
358
359int mmio_trace_printk(const char *fmt, va_list args)
360{
361 return trace_vprintk(0, fmt, args);
362}
363