Re: [PATCH 1/3] efi: Turn boot memmap handling into shared code

On 2026/08/13 09:45, Ard Biesheuvel wrote:
>Move the handling of the boot memmap config table from loongarch
>specific code to code that is shared between all architectures that
>select EFI_GENERIC_STUB (all EFI archs except x86).
>
>This will be used in a subsequent patch to replace the clunky FDT based
>passing of the memmap parameters.
>
>Signed-off-by: Ard Biesheuvel <[email protected]>
>---
> arch/loongarch/kernel/efi.c | 10 ++++------
> drivers/firmware/efi/efi.c  |  4 ++++
> include/linux/efi.h         |  3 +++
> 3 files changed, 11 insertions(+), 6 deletions(-)
>
>diff --git a/arch/loongarch/kernel/efi.c b/arch/loongarch/kernel/efi.c
>index 69dd83f8082f..089378856bab 100644
>--- a/arch/loongarch/kernel/efi.c
>+++ b/arch/loongarch/kernel/efi.c
>@@ -28,12 +28,10 @@
> static unsigned long efi_nr_tables;
> static unsigned long efi_config_table;
>
>-static unsigned long __initdata boot_memmap = EFI_INVALID_TABLE_ADDR;
> static unsigned long __initdata fdt_pointer = EFI_INVALID_TABLE_ADDR;
>
> static efi_system_table_t *efi_systab;
> static efi_config_table_type_t arch_tables[] __initdata = {
>-	{LINUX_EFI_BOOT_MEMMAP_GUID,	&boot_memmap,	"MEMMAP" },
> 	{DEVICE_TREE_GUID,		&fdt_pointer,	"FDTPTR" },
> 	{},
> };
>@@ -132,14 +130,14 @@ void __init efi_init(void)
> 	if (IS_ENABLED(CONFIG_EFI_EARLYCON) || IS_ENABLED(CONFIG_SYSFB))
> 		init_primary_display();
>
>-	if (boot_memmap == EFI_INVALID_TABLE_ADDR)
>+	if (efi.boot_memmap == EFI_INVALID_TABLE_ADDR)
> 		return;
>
>-	tbl = early_memremap_ro(boot_memmap, sizeof(*tbl));
>+	tbl = early_memremap_ro(efi.boot_memmap, sizeof(*tbl));
> 	if (tbl) {
> 		struct efi_memory_map_data data;
>
>-		data.phys_map		= boot_memmap + sizeof(*tbl);
>+		data.phys_map		= efi.boot_memmap + sizeof(*tbl);
> 		data.size		= tbl->map_size;
> 		data.desc_size		= tbl->desc_size;
> 		data.desc_version	= tbl->desc_ver;
>@@ -156,7 +154,7 @@ void __init efi_init(void)
> 		 * Also, set the EFI_PRESERVE_BS_REGIONS flag to indicate that
> 		 * critical boot services code/data regions like this are preserved.
> 		 */
>-		memblock_reserve((phys_addr_t)boot_memmap, sizeof(*tbl) + data.size);
>+		memblock_reserve((phys_addr_t)efi.boot_memmap, sizeof(*tbl) + data.size);
> 		set_bit(EFI_PRESERVE_BS_REGIONS, &efi.flags);
>
> 		early_memunmap(tbl, sizeof(*tbl));
>diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
>index 0327a39d31fa..d33760d6a527 100644
>--- a/drivers/firmware/efi/efi.c
>+++ b/drivers/firmware/efi/efi.c
>@@ -55,6 +55,9 @@ struct efi __read_mostly efi = {
> #ifdef CONFIG_UNACCEPTED_MEMORY
> 	.unaccepted		= EFI_INVALID_TABLE_ADDR,
> #endif
>+#ifdef CONFIG_EFI_GENERIC_STUB
>+	.boot_memmap		= EFI_INVALID_TABLE_ADDR,
>+#endif
> };
> EXPORT_SYMBOL(efi);
>
>@@ -647,6 +650,7 @@ static const efi_config_table_type_t common_tables[] __initconst = {
> 	{LINUX_EFI_UNACCEPTED_MEM_TABLE_GUID,	&efi.unaccepted,	"Unaccepted"	},
> #endif
> #ifdef CONFIG_EFI_GENERIC_STUB
>+	{LINUX_EFI_BOOT_MEMMAP_GUID,		&efi.boot_memmap,	"MEMMAP"	},
> 	{LINUX_EFI_PRIMARY_DISPLAY_TABLE_GUID,	&primary_display_table			},
> #endif
> 	{},
>diff --git a/include/linux/efi.h b/include/linux/efi.h
>index aa15ff88539b..bc1cd005ca0f 100644
>--- a/include/linux/efi.h
>+++ b/include/linux/efi.h
>@@ -650,6 +650,9 @@ extern struct efi {
> 	unsigned long			mokvar_table;		/* MOK variable config table */
> 	unsigned long			coco_secret;		/* Confidential computing secret table */
> 	unsigned long			unaccepted;		/* Unaccepted memory table */
>+#ifdef CONFIG_EFI_GENERIC_STUB
>+	unsigned long			boot_memmap;		/* The EFI memory map captured by the stub */
>+#endif
>
> 	efi_get_time_t			*get_time;
> 	efi_set_time_t			*set_time;
>-- 
>2.47.3
>
>

Reviewed-by: Richard Lyu <[email protected]>