linux-kernel - [PATCH v3 4/6] drm/i915/gem: Add i915_gem_object_panic

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Message-ID: <20241210093505.589893-5-jfalempe@redhat.com>
Date: Tue, 10 Dec 2024 10:28:44 +0100
From: Jocelyn Falempe <jfalempe@...hat.com>
To: Jani Nikula <jani.nikula@...ux.intel.com>,
	Rodrigo Vivi <rodrigo.vivi@...el.com>,
	Joonas Lahtinen <joonas.lahtinen@...ux.intel.com>,
	Tvrtko Ursulin <tursulin@...ulin.net>,
	David Airlie <airlied@...il.com>,
	Simona Vetter <simona@...ll.ch>,
	intel-gfx@...ts.freedesktop.org,
	intel-xe@...ts.freedesktop.org,
	dri-devel@...ts.freedesktop.org,
	linux-kernel@...r.kernel.org
Cc: Jocelyn Falempe <jfalempe@...hat.com>
Subject: [PATCH v3 4/6] drm/i915/gem: Add i915_gem_object_panic_map()

Prepare the work for drm_panic support. This is used to map the
current framebuffer, so the CPU can overwrite it with the panic
message.

Signed-off-by: Jocelyn Falempe <jfalempe@...hat.com>
---
 drivers/gpu/drm/i915/display/intel_bo.c    | 10 +++++++++
 drivers/gpu/drm/i915/display/intel_bo.h    |  2 ++
 drivers/gpu/drm/i915/gem/i915_gem_object.h |  2 ++
 drivers/gpu/drm/i915/gem/i915_gem_pages.c  | 25 ++++++++++++++++++++++
 drivers/gpu/drm/xe/display/intel_bo.c      | 11 ++++++++++
 5 files changed, 50 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_bo.c b/drivers/gpu/drm/i915/display/intel_bo.c
index fbd16d7b58d95..5eeb3ba827edf 100644
--- a/drivers/gpu/drm/i915/display/intel_bo.c
+++ b/drivers/gpu/drm/i915/display/intel_bo.c
@@ -22,6 +22,11 @@ bool intel_bo_is_shmem(struct drm_gem_object *obj)
 	return i915_gem_object_is_shmem(to_intel_bo(obj));
 }
 
+bool intel_bo_has_iomem(struct drm_gem_object *obj)
+{
+	return i915_gem_object_has_iomem(to_intel_bo(obj));
+}
+
 bool intel_bo_is_protected(struct drm_gem_object *obj)
 {
 	return i915_gem_object_is_protected(to_intel_bo(obj));
@@ -57,3 +62,8 @@ void intel_bo_describe(struct seq_file *m, struct drm_gem_object *obj)
 {
 	i915_debugfs_describe_obj(m, to_intel_bo(obj));
 }
+
+void *intel_bo_panic_map(struct drm_gem_object *obj)
+{
+	return i915_gem_object_panic_map(to_intel_bo(obj));
+}
diff --git a/drivers/gpu/drm/i915/display/intel_bo.h b/drivers/gpu/drm/i915/display/intel_bo.h
index ea7a2253aaa57..0eb084955e9af 100644
--- a/drivers/gpu/drm/i915/display/intel_bo.h
+++ b/drivers/gpu/drm/i915/display/intel_bo.h
@@ -13,6 +13,7 @@ struct vm_area_struct;
 bool intel_bo_is_tiled(struct drm_gem_object *obj);
 bool intel_bo_is_userptr(struct drm_gem_object *obj);
 bool intel_bo_is_shmem(struct drm_gem_object *obj);
+bool intel_bo_has_iomem(struct drm_gem_object *obj);
 bool intel_bo_is_protected(struct drm_gem_object *obj);
 void intel_bo_flush_if_display(struct drm_gem_object *obj);
 int intel_bo_fb_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma);
@@ -23,5 +24,6 @@ struct intel_frontbuffer *intel_bo_set_frontbuffer(struct drm_gem_object *obj,
 						   struct intel_frontbuffer *front);
 
 void intel_bo_describe(struct seq_file *m, struct drm_gem_object *obj);
+void *intel_bo_panic_map(struct drm_gem_object *obj);
 
 #endif /* __INTEL_BO__ */
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object.h b/drivers/gpu/drm/i915/gem/i915_gem_object.h
index 3dc61cbd2e11f..f85326a98aefc 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_object.h
+++ b/drivers/gpu/drm/i915/gem/i915_gem_object.h
@@ -694,6 +694,8 @@ i915_gem_object_unpin_pages(struct drm_i915_gem_object *obj)
 int __i915_gem_object_put_pages(struct drm_i915_gem_object *obj);
 int i915_gem_object_truncate(struct drm_i915_gem_object *obj);
 
+void *i915_gem_object_panic_map(struct drm_i915_gem_object *obj);
+
 /**
  * i915_gem_object_pin_map - return a contiguous mapping of the entire object
  * @obj: the object to map into kernel address space
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_pages.c b/drivers/gpu/drm/i915/gem/i915_gem_pages.c
index 8780aa2431053..07c33169603c9 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_pages.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_pages.c
@@ -355,6 +355,31 @@ static void *i915_gem_object_map_pfn(struct drm_i915_gem_object *obj,
 	return vaddr ?: ERR_PTR(-ENOMEM);
 }
 
+/* Map the current framebuffer for CPU access. Called from panic handler, so no
+ * need to pin or cleanup.
+ */
+void *i915_gem_object_panic_map(struct drm_i915_gem_object *obj)
+{
+	enum i915_map_type has_type;
+	void *ptr;
+
+	ptr = page_unpack_bits(obj->mm.mapping, &has_type);
+
+	if (ptr)
+		return ptr;
+
+	if (i915_gem_object_has_struct_page(obj))
+		ptr = i915_gem_object_map_page(obj, I915_MAP_WB);
+	else
+		ptr = i915_gem_object_map_pfn(obj, I915_MAP_WB);
+
+	if (IS_ERR(ptr))
+		return NULL;
+
+	obj->mm.mapping = page_pack_bits(ptr, I915_MAP_WB);
+	return ptr;
+}
+
 /* get, pin, and map the pages of the object into kernel space */
 void *i915_gem_object_pin_map(struct drm_i915_gem_object *obj,
 			      enum i915_map_type type)
diff --git a/drivers/gpu/drm/xe/display/intel_bo.c b/drivers/gpu/drm/xe/display/intel_bo.c
index 9f54fad0f1c0c..c05feeeec3806 100644
--- a/drivers/gpu/drm/xe/display/intel_bo.c
+++ b/drivers/gpu/drm/xe/display/intel_bo.c
@@ -23,6 +23,11 @@ bool intel_bo_is_shmem(struct drm_gem_object *obj)
 	return false;
 }
 
+bool intel_bo_has_iomem(struct drm_gem_object *obj)
+{
+	return false;
+}
+
 bool intel_bo_is_protected(struct drm_gem_object *obj)
 {
 	return false;
@@ -82,3 +87,9 @@ void intel_bo_describe(struct seq_file *m, struct drm_gem_object *obj)
 {
 	/* FIXME */
 }
+
+void *intel_bo_panic_map(struct drm_gem_object *obj)
+{
+	/* TODO: map the object so CPU can write the panic screen to it */
+	return NULL;
+}
-- 
2.47.1