xref: /kernel/linux/linux-6.6/drivers/gpu/drm/msm/msm_rd.c (revision 62306a36) 
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2013 Red Hat
4 * Author: Rob Clark <robdclark@gmail.com>
5 */
6
7/* For debugging crashes, userspace can:
8 *
9 *   tail -f /sys/kernel/debug/dri/<minor>/rd > logfile.rd
10 *
11 * to log the cmdstream in a format that is understood by freedreno/cffdump
12 * utility.  By comparing the last successfully completed fence #, to the
13 * cmdstream for the next fence, you can narrow down which process and submit
14 * caused the gpu crash/lockup.
15 *
16 * Additionally:
17 *
18 *   tail -f /sys/kernel/debug/dri/<minor>/hangrd > logfile.rd
19 *
20 * will capture just the cmdstream from submits which triggered a GPU hang.
21 *
22 * This bypasses drm_debugfs_create_files() mainly because we need to use
23 * our own fops for a bit more control.  In particular, we don't want to
24 * do anything if userspace doesn't have the debugfs file open.
25 *
26 * The module-param "rd_full", which defaults to false, enables snapshotting
27 * all (non-written) buffers in the submit, rather than just cmdstream bo's.
28 * This is useful to capture the contents of (for example) vbo's or textures,
29 * or shader programs (if not emitted inline in cmdstream).
30 */
31
32#include <linux/circ_buf.h>
33#include <linux/debugfs.h>
34#include <linux/kfifo.h>
35#include <linux/uaccess.h>
36#include <linux/wait.h>
37
38#include <drm/drm_file.h>
39
40#include "msm_drv.h"
41#include "msm_gpu.h"
42#include "msm_gem.h"
43
44bool rd_full = false;
45MODULE_PARM_DESC(rd_full, "If true, $debugfs/.../rd will snapshot all buffer contents");
46module_param_named(rd_full, rd_full, bool, 0600);
47
48#ifdef CONFIG_DEBUG_FS
49
50enum rd_sect_type {
51	RD_NONE,
52	RD_TEST,       /* ascii text */
53	RD_CMD,        /* ascii text */
54	RD_GPUADDR,    /* u32 gpuaddr, u32 size */
55	RD_CONTEXT,    /* raw dump */
56	RD_CMDSTREAM,  /* raw dump */
57	RD_CMDSTREAM_ADDR, /* gpu addr of cmdstream */
58	RD_PARAM,      /* u32 param_type, u32 param_val, u32 bitlen */
59	RD_FLUSH,      /* empty, clear previous params */
60	RD_PROGRAM,    /* shader program, raw dump */
61	RD_VERT_SHADER,
62	RD_FRAG_SHADER,
63	RD_BUFFER_CONTENTS,
64	RD_GPU_ID,
65	RD_CHIP_ID,
66};
67
68#define BUF_SZ 512  /* should be power of 2 */
69
70/* space used: */
71#define circ_count(circ) \
72	(CIRC_CNT((circ)->head, (circ)->tail, BUF_SZ))
73#define circ_count_to_end(circ) \
74	(CIRC_CNT_TO_END((circ)->head, (circ)->tail, BUF_SZ))
75/* space available: */
76#define circ_space(circ) \
77	(CIRC_SPACE((circ)->head, (circ)->tail, BUF_SZ))
78#define circ_space_to_end(circ) \
79	(CIRC_SPACE_TO_END((circ)->head, (circ)->tail, BUF_SZ))
80
81struct msm_rd_state {
82	struct drm_device *dev;
83
84	bool open;
85
86	/* fifo access is synchronized on the producer side by
87	 * write_lock.  And read_lock synchronizes the reads
88	 */
89	struct mutex read_lock, write_lock;
90
91	wait_queue_head_t fifo_event;
92	struct circ_buf fifo;
93
94	char buf[BUF_SZ];
95};
96
97static void rd_write(struct msm_rd_state *rd, const void *buf, int sz)
98{
99	struct circ_buf *fifo = &rd->fifo;
100	const char *ptr = buf;
101
102	while (sz > 0) {
103		char *fptr = &fifo->buf[fifo->head];
104		int n;
105
106		wait_event(rd->fifo_event, circ_space(&rd->fifo) > 0 || !rd->open);
107		if (!rd->open)
108			return;
109
110		/* Note that smp_load_acquire() is not strictly required
111		 * as CIRC_SPACE_TO_END() does not access the tail more
112		 * than once.
113		 */
114		n = min(sz, circ_space_to_end(&rd->fifo));
115		memcpy(fptr, ptr, n);
116
117		smp_store_release(&fifo->head, (fifo->head + n) & (BUF_SZ - 1));
118		sz  -= n;
119		ptr += n;
120
121		wake_up_all(&rd->fifo_event);
122	}
123}
124
125static void rd_write_section(struct msm_rd_state *rd,
126		enum rd_sect_type type, const void *buf, int sz)
127{
128	rd_write(rd, &type, 4);
129	rd_write(rd, &sz, 4);
130	rd_write(rd, buf, sz);
131}
132
133static ssize_t rd_read(struct file *file, char __user *buf,
134		size_t sz, loff_t *ppos)
135{
136	struct msm_rd_state *rd = file->private_data;
137	struct circ_buf *fifo = &rd->fifo;
138	const char *fptr = &fifo->buf[fifo->tail];
139	int n = 0, ret = 0;
140
141	mutex_lock(&rd->read_lock);
142
143	ret = wait_event_interruptible(rd->fifo_event,
144			circ_count(&rd->fifo) > 0);
145	if (ret)
146		goto out;
147
148	/* Note that smp_load_acquire() is not strictly required
149	 * as CIRC_CNT_TO_END() does not access the head more than
150	 * once.
151	 */
152	n = min_t(int, sz, circ_count_to_end(&rd->fifo));
153	if (copy_to_user(buf, fptr, n)) {
154		ret = -EFAULT;
155		goto out;
156	}
157
158	smp_store_release(&fifo->tail, (fifo->tail + n) & (BUF_SZ - 1));
159	*ppos += n;
160
161	wake_up_all(&rd->fifo_event);
162
163out:
164	mutex_unlock(&rd->read_lock);
165	if (ret)
166		return ret;
167	return n;
168}
169
170static int rd_open(struct inode *inode, struct file *file)
171{
172	struct msm_rd_state *rd = inode->i_private;
173	struct drm_device *dev = rd->dev;
174	struct msm_drm_private *priv = dev->dev_private;
175	struct msm_gpu *gpu = priv->gpu;
176	uint64_t val;
177	uint32_t gpu_id;
178	uint32_t zero = 0;
179	int ret = 0;
180
181	if (!gpu)
182		return -ENODEV;
183
184	mutex_lock(&gpu->lock);
185
186	if (rd->open) {
187		ret = -EBUSY;
188		goto out;
189	}
190
191	file->private_data = rd;
192	rd->open = true;
193
194	/* Reset fifo to clear any previously unread data: */
195	rd->fifo.head = rd->fifo.tail = 0;
196
197	/* the parsing tools need to know gpu-id to know which
198	 * register database to load.
199	 *
200	 * Note: These particular params do not require a context
201	 */
202	gpu->funcs->get_param(gpu, NULL, MSM_PARAM_GPU_ID, &val, &zero);
203	gpu_id = val;
204
205	rd_write_section(rd, RD_GPU_ID, &gpu_id, sizeof(gpu_id));
206
207	gpu->funcs->get_param(gpu, NULL, MSM_PARAM_CHIP_ID, &val, &zero);
208	rd_write_section(rd, RD_CHIP_ID, &val, sizeof(val));
209
210out:
211	mutex_unlock(&gpu->lock);
212	return ret;
213}
214
215static int rd_release(struct inode *inode, struct file *file)
216{
217	struct msm_rd_state *rd = inode->i_private;
218
219	rd->open = false;
220	wake_up_all(&rd->fifo_event);
221
222	return 0;
223}
224
225
226static const struct file_operations rd_debugfs_fops = {
227	.owner = THIS_MODULE,
228	.open = rd_open,
229	.read = rd_read,
230	.llseek = no_llseek,
231	.release = rd_release,
232};
233
234
235static void rd_cleanup(struct msm_rd_state *rd)
236{
237	if (!rd)
238		return;
239
240	mutex_destroy(&rd->read_lock);
241	mutex_destroy(&rd->write_lock);
242	kfree(rd);
243}
244
245static struct msm_rd_state *rd_init(struct drm_minor *minor, const char *name)
246{
247	struct msm_rd_state *rd;
248
249	rd = kzalloc(sizeof(*rd), GFP_KERNEL);
250	if (!rd)
251		return ERR_PTR(-ENOMEM);
252
253	rd->dev = minor->dev;
254	rd->fifo.buf = rd->buf;
255
256	mutex_init(&rd->read_lock);
257	mutex_init(&rd->write_lock);
258
259	init_waitqueue_head(&rd->fifo_event);
260
261	debugfs_create_file(name, S_IFREG | S_IRUGO, minor->debugfs_root, rd,
262			    &rd_debugfs_fops);
263
264	return rd;
265}
266
267int msm_rd_debugfs_init(struct drm_minor *minor)
268{
269	struct msm_drm_private *priv = minor->dev->dev_private;
270	struct msm_rd_state *rd;
271	int ret;
272
273	/* only create on first minor: */
274	if (priv->rd)
275		return 0;
276
277	rd = rd_init(minor, "rd");
278	if (IS_ERR(rd)) {
279		ret = PTR_ERR(rd);
280		goto fail;
281	}
282
283	priv->rd = rd;
284
285	rd = rd_init(minor, "hangrd");
286	if (IS_ERR(rd)) {
287		ret = PTR_ERR(rd);
288		goto fail;
289	}
290
291	priv->hangrd = rd;
292
293	return 0;
294
295fail:
296	msm_rd_debugfs_cleanup(priv);
297	return ret;
298}
299
300void msm_rd_debugfs_cleanup(struct msm_drm_private *priv)
301{
302	rd_cleanup(priv->rd);
303	priv->rd = NULL;
304
305	rd_cleanup(priv->hangrd);
306	priv->hangrd = NULL;
307}
308
309static void snapshot_buf(struct msm_rd_state *rd,
310		struct msm_gem_submit *submit, int idx,
311		uint64_t iova, uint32_t size, bool full)
312{
313	struct drm_gem_object *obj = submit->bos[idx].obj;
314	unsigned offset = 0;
315	const char *buf;
316
317	if (iova) {
318		offset = iova - submit->bos[idx].iova;
319	} else {
320		iova = submit->bos[idx].iova;
321		size = obj->size;
322	}
323
324	/*
325	 * Always write the GPUADDR header so can get a complete list of all the
326	 * buffers in the cmd
327	 */
328	rd_write_section(rd, RD_GPUADDR,
329			(uint32_t[3]){ iova, size, iova >> 32 }, 12);
330
331	if (!full)
332		return;
333
334	/* But only dump the contents of buffers marked READ */
335	if (!(submit->bos[idx].flags & MSM_SUBMIT_BO_READ))
336		return;
337
338	buf = msm_gem_get_vaddr_active(obj);
339	if (IS_ERR(buf))
340		return;
341
342	buf += offset;
343
344	rd_write_section(rd, RD_BUFFER_CONTENTS, buf, size);
345
346	msm_gem_put_vaddr_locked(obj);
347}
348
349/* called under gpu->lock */
350void msm_rd_dump_submit(struct msm_rd_state *rd, struct msm_gem_submit *submit,
351		const char *fmt, ...)
352{
353	struct task_struct *task;
354	char msg[256];
355	int i, n;
356
357	if (!rd->open)
358		return;
359
360	mutex_lock(&rd->write_lock);
361
362	if (fmt) {
363		va_list args;
364
365		va_start(args, fmt);
366		n = vscnprintf(msg, sizeof(msg), fmt, args);
367		va_end(args);
368
369		rd_write_section(rd, RD_CMD, msg, ALIGN(n, 4));
370	}
371
372	rcu_read_lock();
373	task = pid_task(submit->pid, PIDTYPE_PID);
374	if (task) {
375		n = scnprintf(msg, sizeof(msg), "%.*s/%d: fence=%u",
376				TASK_COMM_LEN, task->comm,
377				pid_nr(submit->pid), submit->seqno);
378	} else {
379		n = scnprintf(msg, sizeof(msg), "???/%d: fence=%u",
380				pid_nr(submit->pid), submit->seqno);
381	}
382	rcu_read_unlock();
383
384	rd_write_section(rd, RD_CMD, msg, ALIGN(n, 4));
385
386	for (i = 0; i < submit->nr_bos; i++)
387		snapshot_buf(rd, submit, i, 0, 0, should_dump(submit, i));
388
389	for (i = 0; i < submit->nr_cmds; i++) {
390		uint32_t szd  = submit->cmd[i].size; /* in dwords */
391
392		/* snapshot cmdstream bo's (if we haven't already): */
393		if (!should_dump(submit, i)) {
394			snapshot_buf(rd, submit, submit->cmd[i].idx,
395					submit->cmd[i].iova, szd * 4, true);
396		}
397	}
398
399	for (i = 0; i < submit->nr_cmds; i++) {
400		uint64_t iova = submit->cmd[i].iova;
401		uint32_t szd  = submit->cmd[i].size; /* in dwords */
402
403		switch (submit->cmd[i].type) {
404		case MSM_SUBMIT_CMD_IB_TARGET_BUF:
405			/* ignore IB-targets, we've logged the buffer, the
406			 * parser tool will follow the IB based on the logged
407			 * buffer/gpuaddr, so nothing more to do.
408			 */
409			break;
410		case MSM_SUBMIT_CMD_CTX_RESTORE_BUF:
411		case MSM_SUBMIT_CMD_BUF:
412			rd_write_section(rd, RD_CMDSTREAM_ADDR,
413				(uint32_t[3]){ iova, szd, iova >> 32 }, 12);
414			break;
415		}
416	}
417
418	mutex_unlock(&rd->write_lock);
419}
420#endif
421