[Intel-gfx] [RFC PATCH 07/11] drm/i915/params: add i915 parameters to debugfs

Jani Nikula jani.nikula at intel.com
Fri Dec 21 13:31:42 UTC 2018


Add a debugfs subdirectory i915_params with all the i915 module
parameters. This is a first step, with lots of boilerplate, and not much
benefit yet.

Add debugfs permissions to I915_PARAMS_FOR_EACH(). This duplicates the
mode with module parameter sysfs, but the goal is to make the module
parameters read-only.

0 mode will bypass debugfs creation. Use it for verbose_state_checks
which will need special attention in follow-up work.

Signed-off-by: Jani Nikula <jani.nikula at intel.com>
---
 drivers/gpu/drm/i915/i915_debugfs.c | 197 ++++++++++++++++++++++++++++++++++++
 drivers/gpu/drm/i915/i915_params.c  |   2 +-
 drivers/gpu/drm/i915/i915_params.h  |  68 +++++++------
 3 files changed, 233 insertions(+), 34 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index aca26a25ed50..33375cf79713 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -37,6 +37,201 @@ static inline struct drm_i915_private *node_to_i915(struct drm_info_node *node)
 	return to_i915(node->minor->dev);
 }
 
+/* int param */
+static int i915_param_int_show(struct seq_file *m, void *data)
+{
+	int *value = m->private;
+
+	seq_printf(m, "%d\n", *value);
+
+	return 0;
+}
+
+static int i915_param_int_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, i915_param_int_show, inode->i_private);
+}
+
+static ssize_t i915_param_int_write(struct file *file,
+				    const char __user *ubuf, size_t len,
+				    loff_t *offp)
+{
+	struct seq_file *m = file->private_data;
+	int *value = m->private;
+	int ret;
+
+	ret = kstrtoint_from_user(ubuf, len, 0, value);
+
+	return ret ?: len;
+}
+
+static const struct file_operations i915_param_int_fops = {
+	.owner = THIS_MODULE,
+	.open = i915_param_int_open,
+	.read = seq_read,
+	.write = i915_param_int_write,
+	.llseek = default_llseek,
+	.release = single_release,
+};
+
+static const struct file_operations i915_param_int_fops_ro = {
+	.owner = THIS_MODULE,
+	.open = i915_param_int_open,
+	.read = seq_read,
+	.llseek = default_llseek,
+	.release = single_release,
+};
+
+/* unsigned int param */
+static int i915_param_uint_show(struct seq_file *m, void *data)
+{
+	unsigned int *value = m->private;
+
+	seq_printf(m, "%u\n", *value);
+
+	return 0;
+}
+
+static int i915_param_uint_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, i915_param_uint_show, inode->i_private);
+}
+
+static ssize_t i915_param_uint_write(struct file *file,
+				    const char __user *ubuf, size_t len,
+				    loff_t *offp)
+{
+	struct seq_file *m = file->private_data;
+	unsigned int *value = m->private;
+	int ret;
+
+	ret = kstrtouint_from_user(ubuf, len, 0, value);
+
+	return ret ?: len;
+}
+
+static const struct file_operations i915_param_uint_fops = {
+	.owner = THIS_MODULE,
+	.open = i915_param_uint_open,
+	.read = seq_read,
+	.write = i915_param_uint_write,
+	.llseek = default_llseek,
+	.release = single_release,
+};
+
+static const struct file_operations i915_param_uint_fops_ro = {
+	.owner = THIS_MODULE,
+	.open = i915_param_uint_open,
+	.read = seq_read,
+	.llseek = default_llseek,
+	.release = single_release,
+};
+
+/* char * param */
+static int i915_param_charp_show(struct seq_file *m, void *data)
+{
+	const char **s = m->private;
+
+	seq_printf(m, "%s\n", *s);
+
+	return 0;
+}
+
+static int i915_param_charp_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, i915_param_charp_show, inode->i_private);
+}
+
+static ssize_t i915_param_charp_write(struct file *file,
+				      const char __user *ubuf, size_t len,
+				      loff_t *offp)
+{
+	struct seq_file *m = file->private_data;
+	char **s = m->private;
+	char *new, *old;
+
+	/* FIXME: racy */
+	old = *s;
+	new = strndup_user(ubuf, PAGE_SIZE);
+	if (IS_ERR(new))
+		return PTR_ERR(new);
+
+	*s = new;
+
+	kfree(old);
+
+	return len;
+}
+
+static const struct file_operations i915_param_charp_fops = {
+	.owner = THIS_MODULE,
+	.open = i915_param_charp_open,
+	.read = seq_read,
+	.write = i915_param_charp_write,
+	.llseek = default_llseek,
+	.release = single_release,
+};
+
+static const struct file_operations i915_param_charp_fops_ro = {
+	.owner = THIS_MODULE,
+	.open = i915_param_charp_open,
+	.read = seq_read,
+	.llseek = default_llseek,
+	.release = single_release,
+};
+
+static __always_inline void
+_i915_param_create_file(struct dentry *parent, const char *name,
+			const char *type, int mode, void *value)
+{
+	bool ro = !(mode & 0222);
+
+	if (!mode)
+		return;
+
+	if (!__builtin_strcmp(type, "bool"))
+		debugfs_create_bool(name, mode, parent, value);
+	else if (!__builtin_strcmp(type, "int"))
+		debugfs_create_file_unsafe(name, mode, parent, value,
+					   ro ? &i915_param_int_fops_ro :
+					   &i915_param_int_fops);
+	else if (!__builtin_strcmp(type, "unsigned int"))
+		debugfs_create_file_unsafe(name, mode, parent, value,
+					   ro ? &i915_param_uint_fops_ro :
+					   &i915_param_uint_fops);
+	else if (!__builtin_strcmp(type, "char *"))
+		debugfs_create_file(name, mode, parent, value,
+				    ro ? &i915_param_charp_fops_ro :
+				    &i915_param_charp_fops);
+	else
+		WARN(1, "no debugfs fops defined for param type %s (i915.%s)\n",
+		     type, name);
+}
+
+/* add a subdirectory with files for each i915 param */
+static int i915_debugfs_params(struct drm_i915_private *dev_priv)
+{
+	struct drm_minor *minor = dev_priv->drm.primary;
+	struct i915_params *params = &i915_modparams;
+	struct dentry *dir;
+
+	dir = debugfs_create_dir("i915_params", minor->debugfs_root);
+	if (!dir)
+		return -ENOMEM;
+
+	/*
+	 * Note: We could create files for params needing special handling
+	 * here. Set mode in params to 0 to skip the generic create file, or
+	 * just let the generic create file fail silently with -EEXIST.
+	 */
+
+#define REGISTER(T, x, unused, mode, ...) _i915_param_create_file(dir, #x, #T, mode, &params->x);
+	I915_PARAMS_FOR_EACH(REGISTER);
+#undef REGISTER
+
+	return 0;
+}
+
 static int i915_capabilities(struct seq_file *m, void *data)
 {
 	struct drm_i915_private *dev_priv = node_to_i915(m->private);
@@ -4970,6 +5165,8 @@ int i915_debugfs_register(struct drm_i915_private *dev_priv)
 	struct dentry *ent;
 	int i;
 
+	i915_debugfs_params(dev_priv);
+
 	ent = debugfs_create_file("i915_forcewake_user", S_IRUSR,
 				  minor->debugfs_root, to_i915(minor->dev),
 				  &i915_forcewake_fops);
diff --git a/drivers/gpu/drm/i915/i915_params.c b/drivers/gpu/drm/i915/i915_params.c
index 2853b54570eb..b1a8b8f7dac9 100644
--- a/drivers/gpu/drm/i915/i915_params.c
+++ b/drivers/gpu/drm/i915/i915_params.c
@@ -35,7 +35,7 @@
 	MODULE_PARM_DESC(name, desc)
 
 struct i915_params i915_modparams __read_mostly = {
-#define MEMBER(T, member, value) .member = (value),
+#define MEMBER(T, member, value, ...) .member = (value),
 	I915_PARAMS_FOR_EACH(MEMBER)
 #undef MEMBER
 };
diff --git a/drivers/gpu/drm/i915/i915_params.h b/drivers/gpu/drm/i915/i915_params.h
index 98eba6728095..30c32e288efe 100644
--- a/drivers/gpu/drm/i915/i915_params.h
+++ b/drivers/gpu/drm/i915/i915_params.h
@@ -36,46 +36,48 @@ struct drm_printer;
 /*
  * Invoke param, a function-like macro, for each i915 param, with arguments:
  *
- * param(type, name, value)
+ * param(type, name, value, mode)
  *
  * type: parameter type, one of {bool, int, unsigned int, char *}
  * name: name of the parameter
  * value: initial/default value of the parameter
+ * mode: debugfs file permissions, one of {0400, 0600, 0}, use 0 to not create
+ *       debugfs file
  */
 #define I915_PARAMS_FOR_EACH(param) \
-	param(char *, vbt_firmware, NULL) \
-	param(int, modeset, -1) \
-	param(int, lvds_channel_mode, 0) \
-	param(int, panel_use_ssc, -1) \
-	param(int, vbt_sdvo_panel_type, -1) \
-	param(int, enable_dc, -1) \
-	param(int, enable_fbc, -1) \
-	param(int, enable_psr, -1) \
-	param(int, disable_power_well, -1) \
-	param(int, enable_ips, 1) \
-	param(int, invert_brightness, 0) \
-	param(int, enable_guc, 0) \
-	param(int, guc_log_level, -1) \
-	param(char *, guc_firmware_path, NULL) \
-	param(char *, huc_firmware_path, NULL) \
-	param(char *, dmc_firmware_path, NULL) \
-	param(int, mmio_debug, 0) \
-	param(int, edp_vswing, 0) \
-	param(int, reset, 2) \
+	param(char *, vbt_firmware, NULL, 0400) \
+	param(int, modeset, -1, 0400) \
+	param(int, lvds_channel_mode, 0, 0400) \
+	param(int, panel_use_ssc, -1, 0600) \
+	param(int, vbt_sdvo_panel_type, -1, 0400) \
+	param(int, enable_dc, -1, 0400) \
+	param(int, enable_fbc, -1, 0600) \
+	param(int, enable_psr, -1, 0600) \
+	param(int, disable_power_well, -1, 0400) \
+	param(int, enable_ips, 1, 0600) \
+	param(int, invert_brightness, 0, 0600) \
+	param(int, enable_guc, 0, 0400) \
+	param(int, guc_log_level, -1, 0400) \
+	param(char *, guc_firmware_path, NULL, 0400) \
+	param(char *, huc_firmware_path, NULL, 0400) \
+	param(char *, dmc_firmware_path, NULL, 0400) \
+	param(int, mmio_debug, 0, 0600) \
+	param(int, edp_vswing, 0, 0400) \
+	param(int, reset, 2, 0600) \
 	/* leave bools at the end to not create holes */ \
-	param(bool, alpha_support, IS_ENABLED(CONFIG_DRM_I915_ALPHA_SUPPORT)) \
-	param(bool, enable_hangcheck, true) \
-	param(bool, fastboot, false) \
-	param(bool, prefault_disable, false) \
-	param(bool, load_detect_test, false) \
-	param(bool, force_reset_modeset_test, false) \
-	param(bool, error_capture, true) \
-	param(bool, disable_display, false) \
-	param(bool, verbose_state_checks, true) \
-	param(bool, nuclear_pageflip, false) \
-	param(bool, enable_dp_mst, true) \
-	param(bool, enable_dpcd_backlight, false) \
-	param(bool, enable_gvt, false)
+	param(bool, alpha_support, IS_ENABLED(CONFIG_DRM_I915_ALPHA_SUPPORT), 0400) \
+	param(bool, enable_hangcheck, true, 0600) \
+	param(bool, fastboot, false, 0600) \
+	param(bool, prefault_disable, false, 0600) \
+	param(bool, load_detect_test, false, 0600) \
+	param(bool, force_reset_modeset_test, false, 0600) \
+	param(bool, error_capture, true, 0600) \
+	param(bool, disable_display, false, 0400) \
+	param(bool, verbose_state_checks, true, 0) \
+	param(bool, nuclear_pageflip, false, 0400) \
+	param(bool, enable_dp_mst, true, 0600) \
+	param(bool, enable_dpcd_backlight, false, 0600) \
+	param(bool, enable_gvt, false, 0400)
 
 #define MEMBER(T, member, ...) T member;
 struct i915_params {
-- 
2.11.0



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