xref: /linux/drivers/gpu/drm/msm/msm_rd.c (revision 905e46acd3272d04566fec49afbd7ad9e2ed9ae3)
1 /*
2  * Copyright (C) 2013 Red Hat
3  * Author: Rob Clark <robdclark@gmail.com>
4  *
5  * This program is free software; you can redistribute it and/or modify it
6  * under the terms of the GNU General Public License version 2 as published by
7  * the Free Software Foundation.
8  *
9  * This program is distributed in the hope that it will be useful, but WITHOUT
10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
12  * more details.
13  *
14  * You should have received a copy of the GNU General Public License along with
15  * this program.  If not, see <http://www.gnu.org/licenses/>.
16  */
17 
18 /* For debugging crashes, userspace can:
19  *
20  *   tail -f /sys/kernel/debug/dri/<minor>/rd > logfile.rd
21  *
22  * To log the cmdstream in a format that is understood by freedreno/cffdump
23  * utility.  By comparing the last successfully completed fence #, to the
24  * cmdstream for the next fence, you can narrow down which process and submit
25  * caused the gpu crash/lockup.
26  *
27  * This bypasses drm_debugfs_create_files() mainly because we need to use
28  * our own fops for a bit more control.  In particular, we don't want to
29  * do anything if userspace doesn't have the debugfs file open.
30  *
31  * The module-param "rd_full", which defaults to false, enables snapshotting
32  * all (non-written) buffers in the submit, rather than just cmdstream bo's.
33  * This is useful to capture the contents of (for example) vbo's or textures,
34  * or shader programs (if not emitted inline in cmdstream).
35  */
36 
37 #ifdef CONFIG_DEBUG_FS
38 
39 #include <linux/kfifo.h>
40 #include <linux/debugfs.h>
41 #include <linux/circ_buf.h>
42 #include <linux/wait.h>
43 
44 #include "msm_drv.h"
45 #include "msm_gpu.h"
46 #include "msm_gem.h"
47 
48 static bool rd_full = false;
49 MODULE_PARM_DESC(rd_full, "If true, $debugfs/.../rd will snapshot all buffer contents");
50 module_param_named(rd_full, rd_full, bool, 0600);
51 
52 enum rd_sect_type {
53 	RD_NONE,
54 	RD_TEST,       /* ascii text */
55 	RD_CMD,        /* ascii text */
56 	RD_GPUADDR,    /* u32 gpuaddr, u32 size */
57 	RD_CONTEXT,    /* raw dump */
58 	RD_CMDSTREAM,  /* raw dump */
59 	RD_CMDSTREAM_ADDR, /* gpu addr of cmdstream */
60 	RD_PARAM,      /* u32 param_type, u32 param_val, u32 bitlen */
61 	RD_FLUSH,      /* empty, clear previous params */
62 	RD_PROGRAM,    /* shader program, raw dump */
63 	RD_VERT_SHADER,
64 	RD_FRAG_SHADER,
65 	RD_BUFFER_CONTENTS,
66 	RD_GPU_ID,
67 };
68 
69 #define BUF_SZ 512  /* should be power of 2 */
70 
71 /* space used: */
72 #define circ_count(circ) \
73 	(CIRC_CNT((circ)->head, (circ)->tail, BUF_SZ))
74 #define circ_count_to_end(circ) \
75 	(CIRC_CNT_TO_END((circ)->head, (circ)->tail, BUF_SZ))
76 /* space available: */
77 #define circ_space(circ) \
78 	(CIRC_SPACE((circ)->head, (circ)->tail, BUF_SZ))
79 #define circ_space_to_end(circ) \
80 	(CIRC_SPACE_TO_END((circ)->head, (circ)->tail, BUF_SZ))
81 
82 struct msm_rd_state {
83 	struct drm_device *dev;
84 
85 	bool open;
86 
87 	/* current submit to read out: */
88 	struct msm_gem_submit *submit;
89 
90 	/* fifo access is synchronized on the producer side by
91 	 * struct_mutex held by submit code (otherwise we could
92 	 * end up w/ cmds logged in different order than they
93 	 * were executed).  And read_lock synchronizes the reads
94 	 */
95 	struct mutex read_lock;
96 
97 	wait_queue_head_t fifo_event;
98 	struct circ_buf fifo;
99 
100 	char buf[BUF_SZ];
101 };
102 
103 static void rd_write(struct msm_rd_state *rd, const void *buf, int sz)
104 {
105 	struct circ_buf *fifo = &rd->fifo;
106 	const char *ptr = buf;
107 
108 	while (sz > 0) {
109 		char *fptr = &fifo->buf[fifo->head];
110 		int n;
111 
112 		wait_event(rd->fifo_event, circ_space(&rd->fifo) > 0);
113 
114 		n = min(sz, circ_space_to_end(&rd->fifo));
115 		memcpy(fptr, ptr, n);
116 
117 		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 
125 static 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 
133 static 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 	n = min_t(int, sz, circ_count_to_end(&rd->fifo));
149 	if (copy_to_user(buf, fptr, n)) {
150 		ret = -EFAULT;
151 		goto out;
152 	}
153 
154 	fifo->tail = (fifo->tail + n) & (BUF_SZ - 1);
155 	*ppos += n;
156 
157 	wake_up_all(&rd->fifo_event);
158 
159 out:
160 	mutex_unlock(&rd->read_lock);
161 	if (ret)
162 		return ret;
163 	return n;
164 }
165 
166 static int rd_open(struct inode *inode, struct file *file)
167 {
168 	struct msm_rd_state *rd = inode->i_private;
169 	struct drm_device *dev = rd->dev;
170 	struct msm_drm_private *priv = dev->dev_private;
171 	struct msm_gpu *gpu = priv->gpu;
172 	uint64_t val;
173 	uint32_t gpu_id;
174 	int ret = 0;
175 
176 	mutex_lock(&dev->struct_mutex);
177 
178 	if (rd->open || !gpu) {
179 		ret = -EBUSY;
180 		goto out;
181 	}
182 
183 	file->private_data = rd;
184 	rd->open = true;
185 
186 	/* the parsing tools need to know gpu-id to know which
187 	 * register database to load.
188 	 */
189 	gpu->funcs->get_param(gpu, MSM_PARAM_GPU_ID, &val);
190 	gpu_id = val;
191 
192 	rd_write_section(rd, RD_GPU_ID, &gpu_id, sizeof(gpu_id));
193 
194 out:
195 	mutex_unlock(&dev->struct_mutex);
196 	return ret;
197 }
198 
199 static int rd_release(struct inode *inode, struct file *file)
200 {
201 	struct msm_rd_state *rd = inode->i_private;
202 	rd->open = false;
203 	return 0;
204 }
205 
206 
207 static const struct file_operations rd_debugfs_fops = {
208 	.owner = THIS_MODULE,
209 	.open = rd_open,
210 	.read = rd_read,
211 	.llseek = no_llseek,
212 	.release = rd_release,
213 };
214 
215 int msm_rd_debugfs_init(struct drm_minor *minor)
216 {
217 	struct msm_drm_private *priv = minor->dev->dev_private;
218 	struct msm_rd_state *rd;
219 	struct dentry *ent;
220 
221 	/* only create on first minor: */
222 	if (priv->rd)
223 		return 0;
224 
225 	rd = kzalloc(sizeof(*rd), GFP_KERNEL);
226 	if (!rd)
227 		return -ENOMEM;
228 
229 	rd->dev = minor->dev;
230 	rd->fifo.buf = rd->buf;
231 
232 	mutex_init(&rd->read_lock);
233 	priv->rd = rd;
234 
235 	init_waitqueue_head(&rd->fifo_event);
236 
237 	ent = debugfs_create_file("rd", S_IFREG | S_IRUGO,
238 			minor->debugfs_root, rd, &rd_debugfs_fops);
239 	if (!ent) {
240 		DRM_ERROR("Cannot create /sys/kernel/debug/dri/%pd/rd\n",
241 				minor->debugfs_root);
242 		goto fail;
243 	}
244 
245 	return 0;
246 
247 fail:
248 	msm_rd_debugfs_cleanup(priv);
249 	return -1;
250 }
251 
252 void msm_rd_debugfs_cleanup(struct msm_drm_private *priv)
253 {
254 	struct msm_rd_state *rd = priv->rd;
255 
256 	if (!rd)
257 		return;
258 
259 	priv->rd = NULL;
260 	mutex_destroy(&rd->read_lock);
261 	kfree(rd);
262 }
263 
264 static void snapshot_buf(struct msm_rd_state *rd,
265 		struct msm_gem_submit *submit, int idx,
266 		uint64_t iova, uint32_t size)
267 {
268 	struct msm_gem_object *obj = submit->bos[idx].obj;
269 	const char *buf;
270 
271 	buf = msm_gem_get_vaddr_locked(&obj->base);
272 	if (IS_ERR(buf))
273 		return;
274 
275 	if (iova) {
276 		buf += iova - submit->bos[idx].iova;
277 	} else {
278 		iova = submit->bos[idx].iova;
279 		size = obj->base.size;
280 	}
281 
282 	rd_write_section(rd, RD_GPUADDR,
283 			(uint32_t[3]){ iova, size, iova >> 32 }, 12);
284 	rd_write_section(rd, RD_BUFFER_CONTENTS, buf, size);
285 
286 	msm_gem_put_vaddr_locked(&obj->base);
287 }
288 
289 /* called under struct_mutex */
290 void msm_rd_dump_submit(struct msm_gem_submit *submit)
291 {
292 	struct drm_device *dev = submit->dev;
293 	struct msm_drm_private *priv = dev->dev_private;
294 	struct msm_rd_state *rd = priv->rd;
295 	char msg[128];
296 	int i, n;
297 
298 	if (!rd->open)
299 		return;
300 
301 	/* writing into fifo is serialized by caller, and
302 	 * rd->read_lock is used to serialize the reads
303 	 */
304 	WARN_ON(!mutex_is_locked(&dev->struct_mutex));
305 
306 	n = snprintf(msg, sizeof(msg), "%.*s/%d: fence=%u",
307 			TASK_COMM_LEN, current->comm, task_pid_nr(current),
308 			submit->fence->seqno);
309 
310 	rd_write_section(rd, RD_CMD, msg, ALIGN(n, 4));
311 
312 	if (rd_full) {
313 		for (i = 0; i < submit->nr_bos; i++) {
314 			/* buffers that are written to probably don't start out
315 			 * with anything interesting:
316 			 */
317 			if (submit->bos[i].flags & MSM_SUBMIT_BO_WRITE)
318 				continue;
319 
320 			snapshot_buf(rd, submit, i, 0, 0);
321 		}
322 	}
323 
324 	for (i = 0; i < submit->nr_cmds; i++) {
325 		uint64_t iova = submit->cmd[i].iova;
326 		uint32_t szd  = submit->cmd[i].size; /* in dwords */
327 
328 		/* snapshot cmdstream bo's (if we haven't already): */
329 		if (!rd_full) {
330 			snapshot_buf(rd, submit, submit->cmd[i].idx,
331 					submit->cmd[i].iova, szd * 4);
332 		}
333 
334 		switch (submit->cmd[i].type) {
335 		case MSM_SUBMIT_CMD_IB_TARGET_BUF:
336 			/* ignore IB-targets, we've logged the buffer, the
337 			 * parser tool will follow the IB based on the logged
338 			 * buffer/gpuaddr, so nothing more to do.
339 			 */
340 			break;
341 		case MSM_SUBMIT_CMD_CTX_RESTORE_BUF:
342 		case MSM_SUBMIT_CMD_BUF:
343 			rd_write_section(rd, RD_CMDSTREAM_ADDR,
344 				(uint32_t[3]){ iova, szd, iova >> 32 }, 12);
345 			break;
346 		}
347 	}
348 }
349 #endif
350