On Tue, Apr 01, 2025 at 02:51:10PM +0200, Jocelyn Falempe wrote:
> 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 <jfale...@redhat.com>
> ---
>
> v5:
> * Use iosys_map for intel_bo_panic_map().
>
> drivers/gpu/drm/i915/display/intel_bo.c | 5 ++++
> drivers/gpu/drm/i915/display/intel_bo.h | 1 +
> drivers/gpu/drm/i915/gem/i915_gem_object.h | 2 ++
> drivers/gpu/drm/i915/gem/i915_gem_pages.c | 29 ++++++++++++++++++++++
> drivers/gpu/drm/xe/display/intel_bo.c | 10 ++++++++
> 5 files changed, 47 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_bo.c
> b/drivers/gpu/drm/i915/display/intel_bo.c
> index fbd16d7b58d9..ac904e9ec7d5 100644
> --- a/drivers/gpu/drm/i915/display/intel_bo.c
> +++ b/drivers/gpu/drm/i915/display/intel_bo.c
> @@ -57,3 +57,8 @@ 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, struct iosys_map *map)
> +{
> + i915_gem_object_panic_map(to_intel_bo(obj), map);
> +}
> diff --git a/drivers/gpu/drm/i915/display/intel_bo.h
> b/drivers/gpu/drm/i915/display/intel_bo.h
> index ea7a2253aaa5..5b6c63d99786 100644
> --- a/drivers/gpu/drm/i915/display/intel_bo.h
> +++ b/drivers/gpu/drm/i915/display/intel_bo.h
> @@ -23,5 +23,6 @@ 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, struct iosys_map *map);
>
> #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 a5f34542135c..b16092707ea5 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_object.h
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_object.h
> @@ -692,6 +692,8 @@ 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, struct
> iosys_map *map);
> +
> /**
> * 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 8780aa243105..718bea6474d7 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_pages.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_pages.c
> @@ -355,6 +355,35 @@ 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, struct
> iosys_map *map)
> +{
> + enum i915_map_type has_type;
> + void *ptr;
> +
> + ptr = page_unpack_bits(obj->mm.mapping, &has_type);
> +
> +
> + if (!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);
WB mapping would require clflushing to make it to the display.
Is that being done somewhere?
> +
> + if (IS_ERR(ptr))
> + return;
What happens when the mapping fails?
> +
> + obj->mm.mapping = page_pack_bits(ptr, I915_MAP_WB);
> + }
> +
> + if (i915_gem_object_has_iomem(obj))
> + iosys_map_set_vaddr_iomem(map, (void __iomem *) ptr);
> + else
> + iosys_map_set_vaddr(map, 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 27437c22bd70..c68166a64336 100644
> --- a/drivers/gpu/drm/xe/display/intel_bo.c
> +++ b/drivers/gpu/drm/xe/display/intel_bo.c
> @@ -59,3 +59,13 @@ void intel_bo_describe(struct seq_file *m, struct
> drm_gem_object *obj)
> {
> /* FIXME */
> }
> +
> +void intel_bo_panic_map(struct drm_gem_object *obj, struct iosys_map *map)
> +{
> + struct xe_bo *bo = gem_to_xe_bo(obj);
> + int ret;
> +
> + ret = ttm_bo_vmap(&bo->ttm, map);
> + if (ret)
> + iosys_map_clear(map);
> +}
> --
> 2.49.0
--
Ville Syrjälä
Intel
