Am 13.10.26 um 11:32 schrieb Màxim Pedraza Padilla:
The DRM splash client shows the boot graphics the firmware left behind,
and needs the image address and size, its offsets and the status bits.
Reading them from bgrt_tab and bgrt_image_size works with drm_client_lib
built in, but it can be a module, and neither is exported:
ERROR: modpost: drivers/gpu/drm/clients/drm_client_lib.ko: symbol 'bgrt_tab'
undefined!
ERROR: modpost: drivers/gpu/drm/clients/drm_client_lib.ko: symbol
'bgrt_image_size' undefined!
Rather than export the data, add an accessor for each of them, exported
GPL only, with stubs in efi-bgrt.h for CONFIG_ACPI_BGRT=n so that users
need no #ifdef of their own. The variables stay global for
drivers/acpi/bgrt.c, and are only written by efi_bgrt_init(): mark them
__ro_after_init.
Reported-by: Mario Limonciello <[email protected]>
Closes:
https://lore.kernel.org/dri-devel/[email protected]/
Suggested-by: Jani Nikula <[email protected]>
Assisted-by: Claude:claude-opus-5-5
Signed-off-by: Màxim Pedraza Padilla <[email protected]>
Reviewed-by: Thomas Zimmermann <[email protected]>
---
drivers/firmware/efi/efi-bgrt.c | 74 ++++++++++++++++++++++++++++++++-
include/linux/efi-bgrt.h | 39 ++++++++++++++++-
2 files changed, 110 insertions(+), 3 deletions(-)
diff --git a/drivers/firmware/efi/efi-bgrt.c b/drivers/firmware/efi/efi-bgrt.c
index 1da451582812..01425c4d2e70 100644
--- a/drivers/firmware/efi/efi-bgrt.c
+++ b/drivers/firmware/efi/efi-bgrt.c
@@ -16,8 +16,8 @@
#include <linux/efi.h>
#include <linux/efi-bgrt.h>
-struct acpi_table_bgrt bgrt_tab;
-size_t bgrt_image_size;
+struct acpi_table_bgrt bgrt_tab __ro_after_init;
+size_t bgrt_image_size __ro_after_init;
struct bmp_header {
u16 id;
@@ -89,3 +89,73 @@ void __init efi_bgrt_init(struct acpi_table_header *table)
out:
memset(bgrt, 0, sizeof(bgrt_tab));
}
+
+/**
+ * efi_bgrt_has_image() - Whether the firmware left a boot graphic
+ *
+ * Return: true if the BGRT points at a BMP image, which efi_bgrt_init()
+ * checked and reserved.
+ */
+bool efi_bgrt_has_image(void)
+{
+ return bgrt_tab.image_address != 0;
+}
+EXPORT_SYMBOL_GPL(efi_bgrt_has_image);
+
+/**
+ * efi_bgrt_image_address() - Physical address of the boot graphic
+ *
+ * Return: the address of the BMP image, or 0 if there is none.
+ */
+phys_addr_t efi_bgrt_image_address(void)
+{
+ return bgrt_tab.image_address;
+}
+EXPORT_SYMBOL_GPL(efi_bgrt_image_address);
+
+/**
+ * efi_bgrt_image_size() - Size of the boot graphic
+ *
+ * Return: the size of the BMP image, as its header gives it, or 0 if there
+ * is none.
+ */
+size_t efi_bgrt_image_size(void)
+{
+ return bgrt_image_size;
+}
+EXPORT_SYMBOL_GPL(efi_bgrt_image_size);
+
+/**
+ * efi_bgrt_status() - Status field of the BGRT
+ *
+ * Return: the status byte. Bit 0 tells whether the image is still on
+ * screen and, since ACPI 6.2, bits 1-2 how far it has to be turned to show
+ * upright (ACPI_BGRT_ORIENTATION_OFFSET).
+ */
+u8 efi_bgrt_status(void)
+{
+ return bgrt_tab.status;
+}
+EXPORT_SYMBOL_GPL(efi_bgrt_status);
+
+/**
+ * efi_bgrt_image_offset_x() - Horizontal position of the boot graphic
+ *
+ * Return: the X offset, in pixels, at which the firmware drew the image.
+ */
+u32 efi_bgrt_image_offset_x(void)
+{
+ return bgrt_tab.image_offset_x;
+}
+EXPORT_SYMBOL_GPL(efi_bgrt_image_offset_x);
+
+/**
+ * efi_bgrt_image_offset_y() - Vertical position of the boot graphic
+ *
+ * Return: the Y offset, in pixels, at which the firmware drew the image.
+ */
+u32 efi_bgrt_image_offset_y(void)
+{
+ return bgrt_tab.image_offset_y;
+}
+EXPORT_SYMBOL_GPL(efi_bgrt_image_offset_y);
diff --git a/include/linux/efi-bgrt.h b/include/linux/efi-bgrt.h
index e6cd51005633..1c287e5fd388 100644
--- a/include/linux/efi-bgrt.h
+++ b/include/linux/efi-bgrt.h
@@ -9,7 +9,14 @@
void efi_bgrt_init(struct acpi_table_header *table);
int __init acpi_parse_bgrt(struct acpi_table_header *table);
-/* The BGRT data itself; only valid if bgrt_image != NULL. */
+bool efi_bgrt_has_image(void);
+phys_addr_t efi_bgrt_image_address(void);
+size_t efi_bgrt_image_size(void);
+u8 efi_bgrt_status(void);
+u32 efi_bgrt_image_offset_x(void);
+u32 efi_bgrt_image_offset_y(void);
+
+/* The BGRT data itself; only valid if efi_bgrt_has_image(). */
extern size_t bgrt_image_size;
extern struct acpi_table_bgrt bgrt_tab;
@@ -21,6 +28,36 @@ static inline int __init acpi_parse_bgrt(struct acpi_table_header *table)
return 0;
}
+static inline bool efi_bgrt_has_image(void)
+{
+ return false;
+}
+
+static inline phys_addr_t efi_bgrt_image_address(void)
+{
+ return 0;
+}
+
+static inline size_t efi_bgrt_image_size(void)
+{
+ return 0;
+}
+
+static inline u8 efi_bgrt_status(void)
+{
+ return 0;
+}
+
+static inline u32 efi_bgrt_image_offset_x(void)
+{
+ return 0;
+}
+
+static inline u32 efi_bgrt_image_offset_y(void)
+{
+ return 0;
+}
+
#endif /* !CONFIG_ACPI_BGRT */
#endif /* _LINUX_EFI_BGRT_H */
--
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstr. 146, 90461 Nürnberg, Germany, www.suse.com
GF: Stefan Gaiser, Jochen Jaser, Abhinav Puri, (HRB 36809, AG Nürnberg)
