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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 /* current submit to read out: */
87 struct msm_gem_submit *submit;
88
89 /* fifo access is synchronized on the producer side by
90 * gpu->lock held by submit code (otherwise we could
91 * end up w/ cmds logged in different order than they
92 * were executed). And read_lock synchronizes the reads
93 */
94 struct mutex read_lock;
95
96 wait_queue_head_t fifo_event;
97 struct circ_buf fifo;
98
99 char buf[BUF_SZ];
100};
101
102static void rd_write(struct msm_rd_state *rd, const void *buf, int sz)
103{
104 struct circ_buf *fifo = &rd->fifo;
105 const char *ptr = buf;
106
107 while (sz > 0) {
108 char *fptr = &fifo->buf[fifo->head];
109 int n;
110
111 wait_event(rd->fifo_event, circ_space(&rd->fifo) > 0 || !rd->open);
112 if (!rd->open)
113 return;
114
115 /* Note that smp_load_acquire() is not strictly required
116 * as CIRC_SPACE_TO_END() does not access the tail more
117 * than once.
118 */
119 n = min(sz, circ_space_to_end(&rd->fifo));
120 memcpy(fptr, ptr, n);
121
122 smp_store_release(&fifo->head, (fifo->head + n) & (BUF_SZ - 1));
123 sz -= n;
124 ptr += n;
125
126 wake_up_all(&rd->fifo_event);
127 }
128}
129
130static void rd_write_section(struct msm_rd_state *rd,
131 enum rd_sect_type type, const void *buf, int sz)
132{
133 rd_write(rd, &type, 4);
134 rd_write(rd, &sz, 4);
135 rd_write(rd, buf, sz);
136}
137
138static ssize_t rd_read(struct file *file, char __user *buf,
139 size_t sz, loff_t *ppos)
140{
141 struct msm_rd_state *rd = file->private_data;
142 struct circ_buf *fifo = &rd->fifo;
143 const char *fptr = &fifo->buf[fifo->tail];
144 int n = 0, ret = 0;
145
146 mutex_lock(&rd->read_lock);
147
148 ret = wait_event_interruptible(rd->fifo_event,
149 circ_count(&rd->fifo) > 0);
150 if (ret)
151 goto out;
152
153 /* Note that smp_load_acquire() is not strictly required
154 * as CIRC_CNT_TO_END() does not access the head more than
155 * once.
156 */
157 n = min_t(int, sz, circ_count_to_end(&rd->fifo));
158 if (copy_to_user(buf, fptr, n)) {
159 ret = -EFAULT;
160 goto out;
161 }
162
163 smp_store_release(&fifo->tail, (fifo->tail + n) & (BUF_SZ - 1));
164 *ppos += n;
165
166 wake_up_all(&rd->fifo_event);
167
168out:
169 mutex_unlock(&rd->read_lock);
170 if (ret)
171 return ret;
172 return n;
173}
174
175static int rd_open(struct inode *inode, struct file *file)
176{
177 struct msm_rd_state *rd = inode->i_private;
178 struct drm_device *dev = rd->dev;
179 struct msm_drm_private *priv = dev->dev_private;
180 struct msm_gpu *gpu = priv->gpu;
181 uint64_t val;
182 uint32_t gpu_id;
183 uint32_t zero = 0;
184 int ret = 0;
185
186 if (!gpu)
187 return -ENODEV;
188
189 mutex_lock(&gpu->lock);
190
191 if (rd->open) {
192 ret = -EBUSY;
193 goto out;
194 }
195
196 file->private_data = rd;
197 rd->open = true;
198
199 /* Reset fifo to clear any previously unread data: */
200 rd->fifo.head = rd->fifo.tail = 0;
201
202 /* the parsing tools need to know gpu-id to know which
203 * register database to load.
204 *
205 * Note: These particular params do not require a context
206 */
207 gpu->funcs->get_param(gpu, NULL, MSM_PARAM_GPU_ID, &val, &zero);
208 gpu_id = val;
209
210 rd_write_section(rd, RD_GPU_ID, &gpu_id, sizeof(gpu_id));
211
212 gpu->funcs->get_param(gpu, NULL, MSM_PARAM_CHIP_ID, &val, &zero);
213 rd_write_section(rd, RD_CHIP_ID, &val, sizeof(val));
214
215out:
216 mutex_unlock(&gpu->lock);
217 return ret;
218}
219
220static int rd_release(struct inode *inode, struct file *file)
221{
222 struct msm_rd_state *rd = inode->i_private;
223
224 rd->open = false;
225 wake_up_all(&rd->fifo_event);
226
227 return 0;
228}
229
230
231static const struct file_operations rd_debugfs_fops = {
232 .owner = THIS_MODULE,
233 .open = rd_open,
234 .read = rd_read,
235 .llseek = no_llseek,
236 .release = rd_release,
237};
238
239
240static void rd_cleanup(struct msm_rd_state *rd)
241{
242 if (!rd)
243 return;
244
245 mutex_destroy(&rd->read_lock);
246 kfree(rd);
247}
248
249static struct msm_rd_state *rd_init(struct drm_minor *minor, const char *name)
250{
251 struct msm_rd_state *rd;
252
253 rd = kzalloc(sizeof(*rd), GFP_KERNEL);
254 if (!rd)
255 return ERR_PTR(-ENOMEM);
256
257 rd->dev = minor->dev;
258 rd->fifo.buf = rd->buf;
259
260 mutex_init(&rd->read_lock);
261
262 init_waitqueue_head(&rd->fifo_event);
263
264 debugfs_create_file(name, S_IFREG | S_IRUGO, minor->debugfs_root, rd,
265 &rd_debugfs_fops);
266
267 return rd;
268}
269
270int msm_rd_debugfs_init(struct drm_minor *minor)
271{
272 struct msm_drm_private *priv = minor->dev->dev_private;
273 struct msm_rd_state *rd;
274 int ret;
275
276 /* only create on first minor: */
277 if (priv->rd)
278 return 0;
279
280 rd = rd_init(minor, "rd");
281 if (IS_ERR(rd)) {
282 ret = PTR_ERR(rd);
283 goto fail;
284 }
285
286 priv->rd = rd;
287
288 rd = rd_init(minor, "hangrd");
289 if (IS_ERR(rd)) {
290 ret = PTR_ERR(rd);
291 goto fail;
292 }
293
294 priv->hangrd = rd;
295
296 return 0;
297
298fail:
299 msm_rd_debugfs_cleanup(priv);
300 return ret;
301}
302
303void msm_rd_debugfs_cleanup(struct msm_drm_private *priv)
304{
305 rd_cleanup(priv->rd);
306 priv->rd = NULL;
307
308 rd_cleanup(priv->hangrd);
309 priv->hangrd = NULL;
310}
311
312static void snapshot_buf(struct msm_rd_state *rd,
313 struct msm_gem_submit *submit, int idx,
314 uint64_t iova, uint32_t size, bool full)
315{
316 struct msm_gem_object *obj = submit->bos[idx].obj;
317 unsigned offset = 0;
318 const char *buf;
319
320 if (iova) {
321 offset = iova - submit->bos[idx].iova;
322 } else {
323 iova = submit->bos[idx].iova;
324 size = obj->base.size;
325 }
326
327 /*
328 * Always write the GPUADDR header so can get a complete list of all the
329 * buffers in the cmd
330 */
331 rd_write_section(rd, RD_GPUADDR,
332 (uint32_t[3]){ iova, size, iova >> 32 }, 12);
333
334 if (!full)
335 return;
336
337 /* But only dump the contents of buffers marked READ */
338 if (!(submit->bos[idx].flags & MSM_SUBMIT_BO_READ))
339 return;
340
341 msm_gem_lock(&obj->base);
342 buf = msm_gem_get_vaddr_active(&obj->base);
343 if (IS_ERR(buf))
344 goto out_unlock;
345
346 buf += offset;
347
348 rd_write_section(rd, RD_BUFFER_CONTENTS, buf, size);
349
350 msm_gem_put_vaddr_locked(&obj->base);
351
352out_unlock:
353 msm_gem_unlock(&obj->base);
354}
355
356/* called under gpu->lock */
357void msm_rd_dump_submit(struct msm_rd_state *rd, struct msm_gem_submit *submit,
358 const char *fmt, ...)
359{
360 struct task_struct *task;
361 char msg[256];
362 int i, n;
363
364 if (!rd->open)
365 return;
366
367 /* writing into fifo is serialized by caller, and
368 * rd->read_lock is used to serialize the reads
369 */
370 WARN_ON(!mutex_is_locked(&submit->gpu->lock));
371
372 if (fmt) {
373 va_list args;
374
375 va_start(args, fmt);
376 n = vscnprintf(msg, sizeof(msg), fmt, args);
377 va_end(args);
378
379 rd_write_section(rd, RD_CMD, msg, ALIGN(n, 4));
380 }
381
382 rcu_read_lock();
383 task = pid_task(submit->pid, PIDTYPE_PID);
384 if (task) {
385 n = scnprintf(msg, sizeof(msg), "%.*s/%d: fence=%u",
386 TASK_COMM_LEN, task->comm,
387 pid_nr(submit->pid), submit->seqno);
388 } else {
389 n = scnprintf(msg, sizeof(msg), "???/%d: fence=%u",
390 pid_nr(submit->pid), submit->seqno);
391 }
392 rcu_read_unlock();
393
394 rd_write_section(rd, RD_CMD, msg, ALIGN(n, 4));
395
396 for (i = 0; i < submit->nr_bos; i++)
397 snapshot_buf(rd, submit, i, 0, 0, should_dump(submit, i));
398
399 for (i = 0; i < submit->nr_cmds; i++) {
400 uint32_t szd = submit->cmd[i].size; /* in dwords */
401
402 /* snapshot cmdstream bo's (if we haven't already): */
403 if (!should_dump(submit, i)) {
404 snapshot_buf(rd, submit, submit->cmd[i].idx,
405 submit->cmd[i].iova, szd * 4, true);
406 }
407 }
408
409 for (i = 0; i < submit->nr_cmds; i++) {
410 uint64_t iova = submit->cmd[i].iova;
411 uint32_t szd = submit->cmd[i].size; /* in dwords */
412
413 switch (submit->cmd[i].type) {
414 case MSM_SUBMIT_CMD_IB_TARGET_BUF:
415 /* ignore IB-targets, we've logged the buffer, the
416 * parser tool will follow the IB based on the logged
417 * buffer/gpuaddr, so nothing more to do.
418 */
419 break;
420 case MSM_SUBMIT_CMD_CTX_RESTORE_BUF:
421 case MSM_SUBMIT_CMD_BUF:
422 rd_write_section(rd, RD_CMDSTREAM_ADDR,
423 (uint32_t[3]){ iova, szd, iova >> 32 }, 12);
424 break;
425 }
426 }
427}
428#endif