drm/i915: Export number of fail injection checkpoints through debugfs

Commit Message

Michał Winiarski June 6, 2018, 11:33 a.m. UTC

We'd like to start testing module load with fault injection. To avoid
making any asumptions on number of available fault injection
checkpoints (either in IGT or in i915), we can compute it at runtime and
export it in debugfs.

Signed-off-by: Michał Winiarski <[e-mail]>
Cc: Chris Wilson <[e-mail]>
Cc: Imre Deak <[e-mail]>
Cc: Joonas Lahtinen <[e-mail]>
---
 drivers/gpu/drm/i915/i915_debugfs.c | 14 ++++++++++++++
 drivers/gpu/drm/i915/i915_drv.c     | 13 +++++--------
 drivers/gpu/drm/i915/i915_drv.h     |  7 +++++--
 3 files changed, 24 insertions(+), 10 deletions(-)

Comments

Chris Wilson June 6, 2018, 11:44 a.m. UTC | #1

Quoting Michał Winiarski (2018-06-06 12:33:56)
> We'd like to start testing module load with fault injection. To avoid
> making any asumptions on number of available fault injection
> checkpoints (either in IGT or in i915), we can compute it at runtime and
> export it in debugfs.

The idea was that we wouldn't need this coupling as we just keep on
adding more faults until the module loads, as then we have hit all the
branches we might.
-Chris

Chris Wilson June 6, 2018, 12:15 p.m. UTC | #2

Quoting Michał Winiarski (2018-06-06 12:33:56)
> We'd like to start testing module load with fault injection. To avoid
> making any asumptions on number of available fault injection
> checkpoints (either in IGT or in i915), we can compute it at runtime and
> export it in debugfs.

Michał pointed out on irc that out igt is completely busted atm and we
have let a number of errors slip in. Oh well.
-Chris

Patch

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 698af45e229c..32cf8bb83ed5 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -2279,6 +2279,17 @@  static int i915_rps_boost_info(struct seq_file *m, void *data)
 	return 0;
 }
 
+#if IS_ENABLED(CONFIG_DRM_I915_DEBUG)
+static int i915_fail_injection_info(struct seq_file *m, void *data)
+{
+	struct drm_i915_private *i915 = node_to_i915(m->private);
+
+	seq_printf(m, "Available checkpoints: %u\n", i915->load_fail_count);
+
+	return 0;
+}
+#endif
+
 static int i915_llc(struct seq_file *m, void *data)
 {
 	struct drm_i915_private *dev_priv = node_to_i915(m->private);
@@ -4797,6 +4808,9 @@  static const struct drm_info_list i915_debugfs_list[] = {
 	{"i915_sseu_status", i915_sseu_status, 0},
 	{"i915_drrs_status", i915_drrs_status, 0},
 	{"i915_rps_boost_info", i915_rps_boost_info, 0},
+#if IS_ENABLED(CONFIG_DRM_I915_DEBUG)
+	{"i915_fail_injection_info", i915_fail_injection_info, 0},
+#endif
 };
 #define I915_DEBUGFS_ENTRIES ARRAY_SIZE(i915_debugfs_list)
 
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 6b599b1837dc..0c3acc255085 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -57,14 +57,11 @@ 
 static struct drm_driver driver;
 
 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG)
-static unsigned int i915_load_fail_count;
 
-bool __i915_inject_load_failure(const char *func, int line)
+bool __i915_inject_load_failure(struct drm_i915_private *i915,
+				const char *func, int line)
 {
-	if (i915_load_fail_count >= i915_modparams.inject_load_failure)
-		return false;
-
-	if (++i915_load_fail_count == i915_modparams.inject_load_failure) {
+	if (++i915->load_fail_count == i915_modparams.inject_load_failure) {
 		DRM_INFO("Injecting failure at checkpoint %u [%s:%d]\n",
 			 i915_modparams.inject_load_failure, func, line);
 		return true;
@@ -114,11 +111,11 @@  __i915_printk(struct drm_i915_private *dev_priv, const char *level,
 	va_end(args);
 }
 
-static bool i915_error_injected(struct drm_i915_private *dev_priv)
+static bool i915_error_injected(struct drm_i915_private *i915)
 {
 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG)
 	return i915_modparams.inject_load_failure &&
-	       i915_load_fail_count == i915_modparams.inject_load_failure;
+	       i915->load_fail_count == i915_modparams.inject_load_failure;
 #else
 	return false;
 #endif
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index a4bb30c32a52..f694e5ebd39f 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -107,9 +107,10 @@ 
 	I915_STATE_WARN((x), "%s", "WARN_ON(" __stringify(x) ")")
 
 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG)
-bool __i915_inject_load_failure(const char *func, int line);
+bool __i915_inject_load_failure(struct drm_i915_private *i915,
+				const char *func, int line);
 #define i915_inject_load_failure() \
-	__i915_inject_load_failure(__func__, __LINE__)
+	__i915_inject_load_failure(dev_priv, __func__, __LINE__)
 #else
 #define i915_inject_load_failure() false
 #endif
@@ -2120,6 +2121,8 @@  struct drm_i915_private {
 
 	struct i915_pmu pmu;
 
+	unsigned int load_fail_count;
+
 	/*
 	 * NOTE: This is the dri1/ums dungeon, don't add stuff here. Your patch
 	 * will be rejected. Instead look for a better place.