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 
21 struct header_iter {
22 	struct pci_dev *dev;
23 };
24 
25 static struct trace_array *mmio_trace_array;
26 static bool overrun_detected;
27 static unsigned long prev_overruns;
28 static atomic_t dropped_count;
29 
30 static 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 
38 static 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 
48 static 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 
57 static void mmio_trace_start(struct trace_array *tr)
58 {
59 	pr_debug("in %s\n", __func__);
60 	mmio_reset_data(tr);
61 }
62 
63 static 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 
91 static 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 
99 static 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! */
115 static 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 
122 static 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 
133 static 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 
162 print_out:
163 	ret = trace_seq_to_user(s, ubuf, cnt);
164 	return (ret == -EBUSY) ? 0 : ret;
165 }
166 
167 static 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 
212 static 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 
246 static 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 
262 static 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 
276 static 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 }
293 device_initcall(init_mmio_trace);
294 
295 static 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 
318 void 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 
325 static 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 
348 void 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 
359 int mmio_trace_printk(const char *fmt, va_list args)
360 {
361 	return trace_vprintk(0, fmt, args);
362 }
363