drivers/gpu/drm/msm/msm_rd.c

   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         struct dentry *ent;
  88         struct drm_info_node *node;
  89
  90         /* current submit to read out: */
  91         struct msm_gem_submit *submit;
  92
  93         /* fifo access is synchronized on the producer side by
  94          * struct_mutex held by submit code (otherwise we could
  95          * end up w/ cmds logged in different order than they
  96          * were executed).  And read_lock synchronizes the reads
  97          */
  98         struct mutex read_lock;
  99
 100         wait_queue_head_t fifo_event;
 101         struct circ_buf fifo;
 102
 103         char buf[BUF_SZ];
 104 };
 105
 106 static void rd_write(struct msm_rd_state *rd, const void *buf, int sz)
 107 {
 108         struct circ_buf *fifo = &rd->fifo;
 109         const char *ptr = buf;
 110
 111         while (sz > 0) {
 112                 char *fptr = &fifo->buf[fifo->head];
 113                 int n;
 114
 115                 wait_event(rd->fifo_event, circ_space(&rd->fifo) > 0);
 116
 117                 n = min(sz, circ_space_to_end(&rd->fifo));
 118                 memcpy(fptr, ptr, n);
 119
 120                 fifo->head = (fifo->head + n) & (BUF_SZ - 1);
 121                 sz  -= n;
 122                 ptr += n;
 123
 124                 wake_up_all(&rd->fifo_event);
 125         }
 126 }
 127
 128 static void rd_write_section(struct msm_rd_state *rd,
 129                 enum rd_sect_type type, const void *buf, int sz)
 130 {
 131         rd_write(rd, &type, 4);
 132         rd_write(rd, &sz, 4);
 133         rd_write(rd, buf, sz);
 134 }
 135
 136 static ssize_t rd_read(struct file *file, char __user *buf,
 137                 size_t sz, loff_t *ppos)
 138 {
 139         struct msm_rd_state *rd = file->private_data;
 140         struct circ_buf *fifo = &rd->fifo;
 141         const char *fptr = &fifo->buf[fifo->tail];
 142         int n = 0, ret = 0;
 143
 144         mutex_lock(&rd->read_lock);
 145
 146         ret = wait_event_interruptible(rd->fifo_event,
 147                         circ_count(&rd->fifo) > 0);
 148         if (ret)
 149                 goto out;
 150
 151         n = min_t(int, sz, circ_count_to_end(&rd->fifo));
 152         if (copy_to_user(buf, fptr, n)) {
 153                 ret = -EFAULT;
 154                 goto out;
 155         }
 156
 157         fifo->tail = (fifo->tail + n) & (BUF_SZ - 1);
 158         *ppos += n;
 159
 160         wake_up_all(&rd->fifo_event);
 161
 162 out:
 163         mutex_unlock(&rd->read_lock);
 164         if (ret)
 165                 return ret;
 166         return n;
 167 }
 168
 169 static int rd_open(struct inode *inode, struct file *file)
 170 {
 171         struct msm_rd_state *rd = inode->i_private;
 172         struct drm_device *dev = rd->dev;
 173         struct msm_drm_private *priv = dev->dev_private;
 174         struct msm_gpu *gpu = priv->gpu;
 175         uint64_t val;
 176         uint32_t gpu_id;
 177         int ret = 0;
 178
 179         mutex_lock(&dev->struct_mutex);
 180
 181         if (rd->open || !gpu) {
 182                 ret = -EBUSY;
 183                 goto out;
 184         }
 185
 186         file->private_data = rd;
 187         rd->open = true;
 188
 189         /* the parsing tools need to know gpu-id to know which
 190          * register database to load.
 191          */
 192         gpu->funcs->get_param(gpu, MSM_PARAM_GPU_ID, &val);
 193         gpu_id = val;
 194
 195         rd_write_section(rd, RD_GPU_ID, &gpu_id, sizeof(gpu_id));
 196
 197 out:
 198         mutex_unlock(&dev->struct_mutex);
 199         return ret;
 200 }
 201
 202 static int rd_release(struct inode *inode, struct file *file)
 203 {
 204         struct msm_rd_state *rd = inode->i_private;
 205         rd->open = false;
 206         return 0;
 207 }
 208
 209
 210 static const struct file_operations rd_debugfs_fops = {
 211         .owner = THIS_MODULE,
 212         .open = rd_open,
 213         .read = rd_read,
 214         .llseek = no_llseek,
 215         .release = rd_release,
 216 };
 217
 218 int msm_rd_debugfs_init(struct drm_minor *minor)
 219 {
 220         struct msm_drm_private *priv = minor->dev->dev_private;
 221         struct msm_rd_state *rd;
 222
 223         /* only create on first minor: */
 224         if (priv->rd)
 225                 return 0;
 226
 227         rd = kzalloc(sizeof(*rd), GFP_KERNEL);
 228         if (!rd)
 229                 return -ENOMEM;
 230
 231         rd->dev = minor->dev;
 232         rd->fifo.buf = rd->buf;
 233
 234         mutex_init(&rd->read_lock);
 235         priv->rd = rd;
 236
 237         init_waitqueue_head(&rd->fifo_event);
 238
 239         rd->node = kzalloc(sizeof(*rd->node), GFP_KERNEL);
 240         if (!rd->node)
 241                 goto fail;
 242
 243         rd->ent = debugfs_create_file("rd", S_IFREG | S_IRUGO,
 244                         minor->debugfs_root, rd, &rd_debugfs_fops);
 245         if (!rd->ent) {
 246                 DRM_ERROR("Cannot create /sys/kernel/debug/dri/%pd/rd\n",
 247                                 minor->debugfs_root);
 248                 goto fail;
 249         }
 250
 251         rd->node->minor = minor;
 252         rd->node->dent  = rd->ent;
 253         rd->node->info_ent = NULL;
 254
 255         mutex_lock(&minor->debugfs_lock);
 256         list_add(&rd->node->list, &minor->debugfs_list);
 257         mutex_unlock(&minor->debugfs_lock);
 258
 259         return 0;
 260
 261 fail:
 262         msm_rd_debugfs_cleanup(minor);
 263         return -1;
 264 }
 265
 266 void msm_rd_debugfs_cleanup(struct drm_minor *minor)
 267 {
 268         struct msm_drm_private *priv = minor->dev->dev_private;
 269         struct msm_rd_state *rd = priv->rd;
 270
 271         if (!rd)
 272                 return;
 273
 274         priv->rd = NULL;
 275
 276         debugfs_remove(rd->ent);
 277
 278         if (rd->node) {
 279                 mutex_lock(&minor->debugfs_lock);
 280                 list_del(&rd->node->list);
 281                 mutex_unlock(&minor->debugfs_lock);
 282                 kfree(rd->node);
 283         }
 284
 285         mutex_destroy(&rd->read_lock);
 286
 287         kfree(rd);
 288 }
 289
 290 static void snapshot_buf(struct msm_rd_state *rd,
 291                 struct msm_gem_submit *submit, int idx,
 292                 uint32_t iova, uint32_t size)
 293 {
 294         struct msm_gem_object *obj = submit->bos[idx].obj;
 295         const char *buf;
 296
 297         buf = msm_gem_get_vaddr_locked(&obj->base);
 298         if (IS_ERR(buf))
 299                 return;
 300
 301         if (iova) {
 302                 buf += iova - submit->bos[idx].iova;
 303         } else {
 304                 iova = submit->bos[idx].iova;
 305                 size = obj->base.size;
 306         }
 307
 308         rd_write_section(rd, RD_GPUADDR,
 309                         (uint32_t[2]){ iova, size }, 8);
 310         rd_write_section(rd, RD_BUFFER_CONTENTS, buf, size);
 311
 312         msm_gem_put_vaddr_locked(&obj->base);
 313 }
 314
 315 /* called under struct_mutex */
 316 void msm_rd_dump_submit(struct msm_gem_submit *submit)
 317 {
 318         struct drm_device *dev = submit->dev;
 319         struct msm_drm_private *priv = dev->dev_private;
 320         struct msm_rd_state *rd = priv->rd;
 321         char msg[128];
 322         int i, n;
 323
 324         if (!rd->open)
 325                 return;
 326
 327         /* writing into fifo is serialized by caller, and
 328          * rd->read_lock is used to serialize the reads
 329          */
 330         WARN_ON(!mutex_is_locked(&dev->struct_mutex));
 331
 332         n = snprintf(msg, sizeof(msg), "%.*s/%d: fence=%u",
 333                         TASK_COMM_LEN, current->comm, task_pid_nr(current),
 334                         submit->fence->seqno);
 335
 336         rd_write_section(rd, RD_CMD, msg, ALIGN(n, 4));
 337
 338         if (rd_full) {
 339                 for (i = 0; i < submit->nr_bos; i++) {
 340                         /* buffers that are written to probably don't start out
 341                          * with anything interesting:
 342                          */
 343                         if (submit->bos[i].flags & MSM_SUBMIT_BO_WRITE)
 344                                 continue;
 345
 346                         snapshot_buf(rd, submit, i, 0, 0);
 347                 }
 348         }
 349
 350         for (i = 0; i < submit->nr_cmds; i++) {
 351                 uint32_t iova = submit->cmd[i].iova;
 352                 uint32_t szd  = submit->cmd[i].size; /* in dwords */
 353
 354                 /* snapshot cmdstream bo's (if we haven't already): */
 355                 if (!rd_full) {
 356                         snapshot_buf(rd, submit, submit->cmd[i].idx,
 357                                         submit->cmd[i].iova, szd * 4);
 358                 }
 359
 360                 switch (submit->cmd[i].type) {
 361                 case MSM_SUBMIT_CMD_IB_TARGET_BUF:
 362                         /* ignore IB-targets, we've logged the buffer, the
 363                          * parser tool will follow the IB based on the logged
 364                          * buffer/gpuaddr, so nothing more to do.
 365                          */
 366                         break;
 367                 case MSM_SUBMIT_CMD_CTX_RESTORE_BUF:
 368                 case MSM_SUBMIT_CMD_BUF:
 369                         rd_write_section(rd, RD_CMDSTREAM_ADDR,
 370                                         (uint32_t[2]){ iova, szd }, 8);
 371                         break;
 372                 }
 373         }
 374 }
 375 #endif