Unlike on arm64, where we can simply access the screen_info struct directly,
ARM requires an intermediate step to get the information discovered by the
GOP code in the UEFI stub into the screen_info struct.
So retrieve the dedicated config table we invented for this purpose, and
put its contents into the core kernel's copy of struct screen_info.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
---
arch/arm/kernel/efi.c | 24 ++++++++++++++++++++
drivers/firmware/efi/arm-init.c | 6 +++++
2 files changed, 30 insertions(+)
diff --git a/arch/arm/kernel/efi.c b/arch/arm/kernel/efi.c
index ff8a9d8acfac..8d1119259654 100644
--- a/arch/arm/kernel/efi.c
+++ b/arch/arm/kernel/efi.c
@@ -6,11 +6,35 @@
* published by the Free Software Foundation.
*/
+#define pr_fmt(fmt) "efi: " fmt
+
#include <linux/efi.h>
+#include <linux/screen_info.h>
#include <asm/efi.h>
#include <asm/mach/map.h>
#include <asm/mmu_context.h>
+static const efi_guid_t __initconst si_tbl = LINUX_ARM32_SCREEN_INFO_TABLE_GUID;
+
+void __init efi_find_screen_info(efi_config_table_t *tbl, u32 num_tables)
+{
+ struct screen_info *si;
+
+ while (num_tables--) {
+ if (efi_guidcmp(tbl->guid, si_tbl) == 0) {
+ si = early_memremap_ro(tbl->table, sizeof(*si));
+ if (!si) {
+ pr_warn("Failed to remap screen_info config table\n");
+ return;
+ }
+ screen_info = *si;
+ early_memunmap(si, sizeof(*si));
+ break;
+ }
+ tbl++;
+ }
+}
+
int __init efi_create_mapping(struct mm_struct *mm, efi_memory_desc_t *md)
{
struct map_desc desc = {
diff --git a/drivers/firmware/efi/arm-init.c b/drivers/firmware/efi/arm-init.c
index eca9b4f826ee..689bf65f8ddf 100644
--- a/drivers/firmware/efi/arm-init.c
+++ b/drivers/firmware/efi/arm-init.c
@@ -112,6 +112,12 @@ static int __init uefi_init(void)
retval = efi_config_parse_tables(config_tables, efi.systab->nr_tables,
sizeof(efi_config_table_t), NULL);
+ if (IS_ENABLED(CONFIG_ARM)) {
+ extern void efi_find_screen_info(efi_config_table_t *, u32);
+
+ efi_find_screen_info(config_tables, efi.systab->nr_tables);
+ }
+
early_memunmap(config_tables, table_size);
out:
early_memunmap(efi.systab, sizeof(efi_system_table_t));
--
1.9.1
--
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