From 780289840868071364ac65d87f1eabc003118a31 Mon Sep 17 00:00:00 2001
From: Jani Nikula <jani.nikula@intel.com>
Date: Wed, 29 Jun 2022 12:27:52 +0300
Subject: drm/edid: add drm_edid_raw() to access the raw EDID data
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Git-commit: 3d1ab66e043f2a143e4d93242de7710a9c98c829
Patch-mainline: v6.0-rc1
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225 jsc#PED-2849

Unfortunately, there are still plenty of interfaces around that require
a struct edid pointer, and it's impossible to change them all at
once. Add an accessor to the raw EDID data to help the transition.

While there are no such cases now, be defensive against raw EDID
extension count indicating bigger EDID than is actually allocated.

Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/fb55d0b580d556bf2b8e58070239657ac9cb4b2f.1656494768.git.jani.nikula@intel.com
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
 drivers/gpu/drm/drm_edid.c | 26 ++++++++++++++++++++++++++
 include/drm/drm_edid.h     |  1 +
 2 files changed, 27 insertions(+)

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index 41b3de52b8f1..1c761e12820e 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -2359,6 +2359,32 @@ struct edid *drm_do_get_edid(struct drm_connector *connector,
 }
 EXPORT_SYMBOL_GPL(drm_do_get_edid);
 
+/**
+ * drm_edid_raw - Get a pointer to the raw EDID data.
+ * @drm_edid: drm_edid container
+ *
+ * Get a pointer to the raw EDID data.
+ *
+ * This is for transition only. Avoid using this like the plague.
+ *
+ * Return: Pointer to raw EDID data.
+ */
+const struct edid *drm_edid_raw(const struct drm_edid *drm_edid)
+{
+	if (!drm_edid || !drm_edid->size)
+		return NULL;
+
+	/*
+	 * Do not return pointers where relying on EDID extension count would
+	 * lead to buffer overflow.
+	 */
+	if (WARN_ON(edid_size(drm_edid->edid) > drm_edid->size))
+		return NULL;
+
+	return drm_edid->edid;
+}
+EXPORT_SYMBOL(drm_edid_raw);
+
 /* Allocate struct drm_edid container *without* duplicating the edid data */
 static const struct drm_edid *_drm_edid_alloc(const void *edid, size_t size)
 {
diff --git a/include/drm/drm_edid.h b/include/drm/drm_edid.h
index aeb2fa95bc04..2181977ae683 100644
--- a/include/drm/drm_edid.h
+++ b/include/drm/drm_edid.h
@@ -597,6 +597,7 @@ drm_display_mode_from_cea_vic(struct drm_device *dev,
 const struct drm_edid *drm_edid_alloc(const void *edid, size_t size);
 const struct drm_edid *drm_edid_dup(const struct drm_edid *drm_edid);
 void drm_edid_free(const struct drm_edid *drm_edid);
+const struct edid *drm_edid_raw(const struct drm_edid *drm_edid);
 const struct drm_edid *drm_edid_read(struct drm_connector *connector);
 const struct drm_edid *drm_edid_read_ddc(struct drm_connector *connector,
 					 struct i2c_adapter *adapter);
-- 
2.38.1