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

source code of linux/kernel/trace/trace_mmiotrace.c