Commit 3f68e695 authored by Sunil V L's avatar Sunil V L Committed by Ard Biesheuvel
Browse files

riscv/efi_stub: Add support for RISCV_EFI_BOOT_PROTOCOL 

Add support for getting the boot hart ID from the Linux EFI stub using
RISCV_EFI_BOOT_PROTOCOL. This method is preferred over the existing DT
based approach since it works irrespective of DT or ACPI.

The specification of the protocol is hosted at:
https://github.com/riscv-non-isa/riscv-uefi



Signed-off-by: default avatarSunil V L <sunilvl@ventanamicro.com>
Acked-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
Reviewed-by: default avatarHeinrich Schuchardt <heinrich.schuchardt@canonical.com>
Link: https://lore.kernel.org/r/20220519051512.136724-2-sunilvl@ventanamicro.com


[ardb: minor tweaks for coding style and whitespace]
Signed-off-by: default avatarArd Biesheuvel <ardb@kernel.org>
parent a6cfe03c

drivers/firmware/efi/libstub/efistub.h

+7 −0
Original line number Diff line number Diff line
@@ -794,6 +794,13 @@ union efi_tcg2_protocol { 
	} mixed_mode;

};



struct riscv_efi_boot_protocol {

	u64 revision;



	efi_status_t (__efiapi *get_boot_hartid)(struct riscv_efi_boot_protocol *,

						 unsigned long *boot_hartid);

};



typedef union efi_load_file_protocol efi_load_file_protocol_t;

typedef union efi_load_file_protocol efi_load_file2_protocol_t;

drivers/firmware/efi/libstub/riscv-stub.c

+23 −6
Original line number Diff line number Diff line
@@ -21,9 +21,9 @@ 
#define MIN_KIMG_ALIGN		SZ_4M

#endif



typedef void __noreturn (*jump_kernel_func)(unsigned int, unsigned long);

typedef void __noreturn (*jump_kernel_func)(unsigned long, unsigned long);



static u32 hartid;

static unsigned long hartid;



static int get_boot_hartid_from_fdt(void)

{
@@ -47,15 +47,32 @@ static int get_boot_hartid_from_fdt(void) 
	return 0;

}



static efi_status_t get_boot_hartid_from_efi(void)

{

	efi_guid_t boot_protocol_guid = RISCV_EFI_BOOT_PROTOCOL_GUID;

	struct riscv_efi_boot_protocol *boot_protocol;

	efi_status_t status;



	status = efi_bs_call(locate_protocol, &boot_protocol_guid, NULL,

			     (void **)&boot_protocol);

	if (status != EFI_SUCCESS)

		return status;

	return efi_call_proto(boot_protocol, get_boot_hartid, &hartid);

}



efi_status_t check_platform_features(void)

{

	efi_status_t status;

	int ret;



	status = get_boot_hartid_from_efi();

	if (status != EFI_SUCCESS) {

		ret = get_boot_hartid_from_fdt();

		if (ret) {

		efi_err("/chosen/boot-hartid missing or invalid!\n");

			efi_err("Failed to get boot hartid!\n");

			return EFI_UNSUPPORTED;

		}

	}

	return EFI_SUCCESS;

}

include/linux/efi.h

+2 −0
Original line number Diff line number Diff line
@@ -410,6 +410,8 @@ void efi_native_runtime_setup(void); 
#define LINUX_EFI_MOK_VARIABLE_TABLE_GUID	EFI_GUID(0xc451ed2b, 0x9694, 0x45d3,  0xba, 0xba, 0xed, 0x9f, 0x89, 0x88, 0xa3, 0x89)

#define LINUX_EFI_COCO_SECRET_AREA_GUID		EFI_GUID(0xadf956ad, 0xe98c, 0x484c,  0xae, 0x11, 0xb5, 0x1c, 0x7d, 0x33, 0x64, 0x47)



#define RISCV_EFI_BOOT_PROTOCOL_GUID		EFI_GUID(0xccd15fec, 0x6f73, 0x4eec,  0x83, 0x95, 0x3e, 0x69, 0xe4, 0xb9, 0x40, 0xbf)



/*

 * This GUID may be installed onto the kernel image's handle as a NULL protocol

 * to signal to the stub that the placement of the image should be respected,