drm/i915: avoid big kmallocs on reading error state
[deliverable/linux.git] / drivers / gpu / drm / i915 / i915_debugfs.c
index a55630a80f830ace22762ed0bd288428733bd812..3a8409a31266ebf0f0544f4905621fa66420a439 100644 (file)
@@ -604,15 +604,80 @@ static const char *purgeable_flag(int purgeable)
        return purgeable ? " purgeable" : "";
 }
 
-static void print_error_buffers(struct seq_file *m,
+static void i915_error_vprintf(struct drm_i915_error_state_buf *e,
+                              const char *f, va_list args)
+{
+       unsigned len;
+
+       if (!e->err && WARN(e->bytes > (e->size - 1), "overflow")) {
+               e->err = -ENOSPC;
+               return;
+       }
+
+       if (e->bytes == e->size - 1 || e->err)
+               return;
+
+       /* Seek the first printf which is hits start position */
+       if (e->pos < e->start) {
+               len = vsnprintf(NULL, 0, f, args);
+               if (e->pos + len <= e->start) {
+                       e->pos += len;
+                       return;
+               }
+
+               /* First vsnprintf needs to fit in full for memmove*/
+               if (len >= e->size) {
+                       e->err = -EIO;
+                       return;
+               }
+       }
+
+       len = vsnprintf(e->buf + e->bytes, e->size - e->bytes, f, args);
+       if (len >= e->size - e->bytes)
+               len = e->size - e->bytes - 1;
+
+       /* If this is first printf in this window, adjust it so that
+        * start position matches start of the buffer
+        */
+       if (e->pos < e->start) {
+               const size_t off = e->start - e->pos;
+
+               /* Should not happen but be paranoid */
+               if (off > len || e->bytes) {
+                       e->err = -EIO;
+                       return;
+               }
+
+               memmove(e->buf, e->buf + off, len - off);
+               e->bytes = len - off;
+               e->pos = e->start;
+               return;
+       }
+
+       e->bytes += len;
+       e->pos += len;
+}
+
+void i915_error_printf(struct drm_i915_error_state_buf *e, const char *f, ...)
+{
+       va_list args;
+
+       va_start(args, f);
+       i915_error_vprintf(e, f, args);
+       va_end(args);
+}
+
+#define err_printf(e, ...) i915_error_printf(e, __VA_ARGS__)
+
+static void print_error_buffers(struct drm_i915_error_state_buf *m,
                                const char *name,
                                struct drm_i915_error_buffer *err,
                                int count)
 {
-       seq_printf(m, "%s [%d]:\n", name, count);
+       err_printf(m, "%s [%d]:\n", name, count);
 
        while (count--) {
-               seq_printf(m, "  %08x %8u %02x %02x %x %x%s%s%s%s%s%s%s",
+               err_printf(m, "  %08x %8u %02x %02x %x %x%s%s%s%s%s%s%s",
                           err->gtt_offset,
                           err->size,
                           err->read_domains,
@@ -627,50 +692,50 @@ static void print_error_buffers(struct seq_file *m,
                           cache_level_str(err->cache_level));
 
                if (err->name)
-                       seq_printf(m, " (name: %d)", err->name);
+                       err_printf(m, " (name: %d)", err->name);
                if (err->fence_reg != I915_FENCE_REG_NONE)
-                       seq_printf(m, " (fence: %d)", err->fence_reg);
+                       err_printf(m, " (fence: %d)", err->fence_reg);
 
-               seq_printf(m, "\n");
+               err_printf(m, "\n");
                err++;
        }
 }
 
-static void i915_ring_error_state(struct seq_file *m,
+static void i915_ring_error_state(struct drm_i915_error_state_buf *m,
                                  struct drm_device *dev,
                                  struct drm_i915_error_state *error,
                                  unsigned ring)
 {
        BUG_ON(ring >= I915_NUM_RINGS); /* shut up confused gcc */
-       seq_printf(m, "%s command stream:\n", ring_str(ring));
-       seq_printf(m, "  HEAD: 0x%08x\n", error->head[ring]);
-       seq_printf(m, "  TAIL: 0x%08x\n", error->tail[ring]);
-       seq_printf(m, "  CTL: 0x%08x\n", error->ctl[ring]);
-       seq_printf(m, "  ACTHD: 0x%08x\n", error->acthd[ring]);
-       seq_printf(m, "  IPEIR: 0x%08x\n", error->ipeir[ring]);
-       seq_printf(m, "  IPEHR: 0x%08x\n", error->ipehr[ring]);
-       seq_printf(m, "  INSTDONE: 0x%08x\n", error->instdone[ring]);
+       err_printf(m, "%s command stream:\n", ring_str(ring));
+       err_printf(m, "  HEAD: 0x%08x\n", error->head[ring]);
+       err_printf(m, "  TAIL: 0x%08x\n", error->tail[ring]);
+       err_printf(m, "  CTL: 0x%08x\n", error->ctl[ring]);
+       err_printf(m, "  ACTHD: 0x%08x\n", error->acthd[ring]);
+       err_printf(m, "  IPEIR: 0x%08x\n", error->ipeir[ring]);
+       err_printf(m, "  IPEHR: 0x%08x\n", error->ipehr[ring]);
+       err_printf(m, "  INSTDONE: 0x%08x\n", error->instdone[ring]);
        if (ring == RCS && INTEL_INFO(dev)->gen >= 4)
-               seq_printf(m, "  BBADDR: 0x%08llx\n", error->bbaddr);
+               err_printf(m, "  BBADDR: 0x%08llx\n", error->bbaddr);
 
        if (INTEL_INFO(dev)->gen >= 4)
-               seq_printf(m, "  INSTPS: 0x%08x\n", error->instps[ring]);
-       seq_printf(m, "  INSTPM: 0x%08x\n", error->instpm[ring]);
-       seq_printf(m, "  FADDR: 0x%08x\n", error->faddr[ring]);
+               err_printf(m, "  INSTPS: 0x%08x\n", error->instps[ring]);
+       err_printf(m, "  INSTPM: 0x%08x\n", error->instpm[ring]);
+       err_printf(m, "  FADDR: 0x%08x\n", error->faddr[ring]);
        if (INTEL_INFO(dev)->gen >= 6) {
-               seq_printf(m, "  RC PSMI: 0x%08x\n", error->rc_psmi[ring]);
-               seq_printf(m, "  FAULT_REG: 0x%08x\n", error->fault_reg[ring]);
-               seq_printf(m, "  SYNC_0: 0x%08x [last synced 0x%08x]\n",
+               err_printf(m, "  RC PSMI: 0x%08x\n", error->rc_psmi[ring]);
+               err_printf(m, "  FAULT_REG: 0x%08x\n", error->fault_reg[ring]);
+               err_printf(m, "  SYNC_0: 0x%08x [last synced 0x%08x]\n",
                           error->semaphore_mboxes[ring][0],
                           error->semaphore_seqno[ring][0]);
-               seq_printf(m, "  SYNC_1: 0x%08x [last synced 0x%08x]\n",
+               err_printf(m, "  SYNC_1: 0x%08x [last synced 0x%08x]\n",
                           error->semaphore_mboxes[ring][1],
                           error->semaphore_seqno[ring][1]);
        }
-       seq_printf(m, "  seqno: 0x%08x\n", error->seqno[ring]);
-       seq_printf(m, "  waiting: %s\n", yesno(error->waiting[ring]));
-       seq_printf(m, "  ring->head: 0x%08x\n", error->cpu_ring_head[ring]);
-       seq_printf(m, "  ring->tail: 0x%08x\n", error->cpu_ring_tail[ring]);
+       err_printf(m, "  seqno: 0x%08x\n", error->seqno[ring]);
+       err_printf(m, "  waiting: %s\n", yesno(error->waiting[ring]));
+       err_printf(m, "  ring->head: 0x%08x\n", error->cpu_ring_head[ring]);
+       err_printf(m, "  ring->tail: 0x%08x\n", error->cpu_ring_tail[ring]);
 }
 
 struct i915_error_state_file_priv {
@@ -678,9 +743,11 @@ struct i915_error_state_file_priv {
        struct drm_i915_error_state *error;
 };
 
-static int i915_error_state(struct seq_file *m, void *unused)
+
+static int i915_error_state(struct i915_error_state_file_priv *error_priv,
+                           struct drm_i915_error_state_buf *m)
+
 {
-       struct i915_error_state_file_priv *error_priv = m->private;
        struct drm_device *dev = error_priv->dev;
        drm_i915_private_t *dev_priv = dev->dev_private;
        struct drm_i915_error_state *error = error_priv->error;
@@ -688,34 +755,35 @@ static int i915_error_state(struct seq_file *m, void *unused)
        int i, j, page, offset, elt;
 
        if (!error) {
-               seq_printf(m, "no error state collected\n");
+               err_printf(m, "no error state collected\n");
                return 0;
        }
 
-       seq_printf(m, "Time: %ld s %ld us\n", error->time.tv_sec,
+       err_printf(m, "Time: %ld s %ld us\n", error->time.tv_sec,
                   error->time.tv_usec);
-       seq_printf(m, "Kernel: " UTS_RELEASE "\n");
-       seq_printf(m, "PCI ID: 0x%04x\n", dev->pci_device);
-       seq_printf(m, "EIR: 0x%08x\n", error->eir);
-       seq_printf(m, "IER: 0x%08x\n", error->ier);
-       seq_printf(m, "PGTBL_ER: 0x%08x\n", error->pgtbl_er);
-       seq_printf(m, "FORCEWAKE: 0x%08x\n", error->forcewake);
-       seq_printf(m, "DERRMR: 0x%08x\n", error->derrmr);
-       seq_printf(m, "CCID: 0x%08x\n", error->ccid);
+       err_printf(m, "Kernel: " UTS_RELEASE "\n");
+       err_printf(m, "PCI ID: 0x%04x\n", dev->pci_device);
+       err_printf(m, "EIR: 0x%08x\n", error->eir);
+       err_printf(m, "IER: 0x%08x\n", error->ier);
+       err_printf(m, "PGTBL_ER: 0x%08x\n", error->pgtbl_er);
+       err_printf(m, "FORCEWAKE: 0x%08x\n", error->forcewake);
+       err_printf(m, "DERRMR: 0x%08x\n", error->derrmr);
+       err_printf(m, "CCID: 0x%08x\n", error->ccid);
 
        for (i = 0; i < dev_priv->num_fence_regs; i++)
-               seq_printf(m, "  fence[%d] = %08llx\n", i, error->fence[i]);
+               err_printf(m, "  fence[%d] = %08llx\n", i, error->fence[i]);
 
        for (i = 0; i < ARRAY_SIZE(error->extra_instdone); i++)
-               seq_printf(m, "  INSTDONE_%d: 0x%08x\n", i, error->extra_instdone[i]);
+               err_printf(m, "  INSTDONE_%d: 0x%08x\n", i,
+                          error->extra_instdone[i]);
 
        if (INTEL_INFO(dev)->gen >= 6) {
-               seq_printf(m, "ERROR: 0x%08x\n", error->error);
-               seq_printf(m, "DONE_REG: 0x%08x\n", error->done_reg);
+               err_printf(m, "ERROR: 0x%08x\n", error->error);
+               err_printf(m, "DONE_REG: 0x%08x\n", error->done_reg);
        }
 
        if (INTEL_INFO(dev)->gen == 7)
-               seq_printf(m, "ERR_INT: 0x%08x\n", error->err_int);
+               err_printf(m, "ERR_INT: 0x%08x\n", error->err_int);
 
        for_each_ring(ring, dev_priv, i)
                i915_ring_error_state(m, dev, error, i);
@@ -734,24 +802,25 @@ static int i915_error_state(struct seq_file *m, void *unused)
                struct drm_i915_error_object *obj;
 
                if ((obj = error->ring[i].batchbuffer)) {
-                       seq_printf(m, "%s --- gtt_offset = 0x%08x\n",
+                       err_printf(m, "%s --- gtt_offset = 0x%08x\n",
                                   dev_priv->ring[i].name,
                                   obj->gtt_offset);
                        offset = 0;
                        for (page = 0; page < obj->page_count; page++) {
                                for (elt = 0; elt < PAGE_SIZE/4; elt++) {
-                                       seq_printf(m, "%08x :  %08x\n", offset, obj->pages[page][elt]);
+                                       err_printf(m, "%08x :  %08x\n", offset,
+                                                  obj->pages[page][elt]);
                                        offset += 4;
                                }
                        }
                }
 
                if (error->ring[i].num_requests) {
-                       seq_printf(m, "%s --- %d requests\n",
+                       err_printf(m, "%s --- %d requests\n",
                                   dev_priv->ring[i].name,
                                   error->ring[i].num_requests);
                        for (j = 0; j < error->ring[i].num_requests; j++) {
-                               seq_printf(m, "  seqno 0x%08x, emitted %ld, tail 0x%08x\n",
+                               err_printf(m, "  seqno 0x%08x, emitted %ld, tail 0x%08x\n",
                                           error->ring[i].requests[j].seqno,
                                           error->ring[i].requests[j].jiffies,
                                           error->ring[i].requests[j].tail);
@@ -759,13 +828,13 @@ static int i915_error_state(struct seq_file *m, void *unused)
                }
 
                if ((obj = error->ring[i].ringbuffer)) {
-                       seq_printf(m, "%s --- ringbuffer = 0x%08x\n",
+                       err_printf(m, "%s --- ringbuffer = 0x%08x\n",
                                   dev_priv->ring[i].name,
                                   obj->gtt_offset);
                        offset = 0;
                        for (page = 0; page < obj->page_count; page++) {
                                for (elt = 0; elt < PAGE_SIZE/4; elt++) {
-                                       seq_printf(m, "%08x :  %08x\n",
+                                       err_printf(m, "%08x :  %08x\n",
                                                   offset,
                                                   obj->pages[page][elt]);
                                        offset += 4;
@@ -775,12 +844,12 @@ static int i915_error_state(struct seq_file *m, void *unused)
 
                obj = error->ring[i].ctx;
                if (obj) {
-                       seq_printf(m, "%s --- HW Context = 0x%08x\n",
+                       err_printf(m, "%s --- HW Context = 0x%08x\n",
                                   dev_priv->ring[i].name,
                                   obj->gtt_offset);
                        offset = 0;
                        for (elt = 0; elt < PAGE_SIZE/16; elt += 4) {
-                               seq_printf(m, "[%04x] %08x %08x %08x %08x\n",
+                               err_printf(m, "[%04x] %08x %08x %08x %08x\n",
                                           offset,
                                           obj->pages[0][elt],
                                           obj->pages[0][elt+1],
@@ -806,8 +875,7 @@ i915_error_state_write(struct file *filp,
                       size_t cnt,
                       loff_t *ppos)
 {
-       struct seq_file *m = filp->private_data;
-       struct i915_error_state_file_priv *error_priv = m->private;
+       struct i915_error_state_file_priv *error_priv = filp->private_data;
        struct drm_device *dev = error_priv->dev;
        int ret;
 
@@ -842,25 +910,81 @@ static int i915_error_state_open(struct inode *inode, struct file *file)
                kref_get(&error_priv->error->ref);
        spin_unlock_irqrestore(&dev_priv->gpu_error.lock, flags);
 
-       return single_open(file, i915_error_state, error_priv);
+       file->private_data = error_priv;
+
+       return 0;
 }
 
 static int i915_error_state_release(struct inode *inode, struct file *file)
 {
-       struct seq_file *m = file->private_data;
-       struct i915_error_state_file_priv *error_priv = m->private;
+       struct i915_error_state_file_priv *error_priv = file->private_data;
 
        if (error_priv->error)
                kref_put(&error_priv->error->ref, i915_error_state_free);
        kfree(error_priv);
 
-       return single_release(inode, file);
+       return 0;
+}
+
+static ssize_t i915_error_state_read(struct file *file, char __user *userbuf,
+                                    size_t count, loff_t *pos)
+{
+       struct i915_error_state_file_priv *error_priv = file->private_data;
+       struct drm_i915_error_state_buf error_str;
+       loff_t tmp_pos = 0;
+       ssize_t ret_count = 0;
+       int ret = 0;
+
+       memset(&error_str, 0, sizeof(error_str));
+
+       /* We need to have enough room to store any i915_error_state printf
+        * so that we can move it to start position.
+        */
+       error_str.size = count + 1 > PAGE_SIZE ? count + 1 : PAGE_SIZE;
+       error_str.buf = kmalloc(error_str.size,
+                               GFP_TEMPORARY | __GFP_NORETRY | __GFP_NOWARN);
+
+       if (error_str.buf == NULL) {
+               error_str.size = PAGE_SIZE;
+               error_str.buf = kmalloc(error_str.size, GFP_TEMPORARY);
+       }
+
+       if (error_str.buf == NULL) {
+               error_str.size = 128;
+               error_str.buf = kmalloc(error_str.size, GFP_TEMPORARY);
+       }
+
+       if (error_str.buf == NULL)
+               return -ENOMEM;
+
+       error_str.start = *pos;
+
+       ret = i915_error_state(error_priv, &error_str);
+       if (ret)
+               goto out;
+
+       if (error_str.bytes == 0 && error_str.err) {
+               ret = error_str.err;
+               goto out;
+       }
+
+       ret_count = simple_read_from_buffer(userbuf, count, &tmp_pos,
+                                           error_str.buf,
+                                           error_str.bytes);
+
+       if (ret_count < 0)
+               ret = ret_count;
+       else
+               *pos = error_str.start + ret_count;
+out:
+       kfree(error_str.buf);
+       return ret ?: ret_count;
 }
 
 static const struct file_operations i915_error_state_fops = {
        .owner = THIS_MODULE,
        .open = i915_error_state_open,
-       .read = seq_read,
+       .read = i915_error_state_read,
        .write = i915_error_state_write,
        .llseek = default_llseek,
        .release = i915_error_state_release,
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