From: Ying-Chun Liu (PaulLiu) Date: Thu, 3 Jul 2025 06:28:07 +0000 (+0100) Subject: efi: add EFI_SYSTEM_TABLE_POINTER for debug X-Git-Tag: v2025.10-rc1~134^2~2^2~5 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=aaf7be96c2c14aa190d39e50fa3606389eafda8e;p=thirdparty%2Fu-boot.git efi: add EFI_SYSTEM_TABLE_POINTER for debug Add EFI_SYSTEM_TABLE_POINTER structure for remote debugger to locate the address of EFI_SYSTEM_TABLE. This feature is described in UEFI SPEC version 2.10. Section 18.4.2. The implementation ensures support for hardware-assisted debugging and provides a standardized mechanism for debuggers to discover the EFI system table. Cc: Peter Robinson Cc: Simon Glass Signed-off-by: Ying-Chun Liu (PaulLiu) Reviewed-by: Ilias Apalodimas Tested-by: Heinrich Schuchardt Reviewed-by: Heinrich Schuchardt # change memset(systab_pointer, 0 ...) -> systab_pointer->crc32 = 0; Signed-off-by: Ilias Apalodimas --- diff --git a/include/efi_api.h b/include/efi_api.h index eb61eafa028..6c4c1a0cc7b 100644 --- a/include/efi_api.h +++ b/include/efi_api.h @@ -259,6 +259,22 @@ struct efi_capsule_result_variable_header { efi_status_t capsule_status; } __packed; +/** + * struct efi_system_table_pointer - struct to store the pointer of system + * table. + * @signature: The signature of this struct. + * @efi_system_table_base: The physical address of System Table. + * @crc32: CRC32 checksum + * + * This struct is design for hardware debugger to search through memory to + * get the address of EFI System Table. + */ +struct efi_system_table_pointer { + u64 signature; + efi_physical_addr_t efi_system_table_base; + u32 crc32; +}; + struct efi_memory_range { efi_physical_addr_t address; u64 length; diff --git a/include/efi_loader.h b/include/efi_loader.h index 8fd09aad2d0..ada29a5bad3 100644 --- a/include/efi_loader.h +++ b/include/efi_loader.h @@ -643,6 +643,8 @@ efi_status_t efi_tcg2_measure_dtb(void *dtb); efi_status_t efi_root_node_register(void); /* Called by bootefi to initialize runtime */ efi_status_t efi_initialize_system_table(void); +/* Called by bootefi to initialize debug */ +efi_status_t efi_initialize_system_table_pointer(void); /* efi_runtime_detach() - detach unimplemented runtime functions */ void efi_runtime_detach(void); /* efi_convert_pointer() - convert pointer to virtual address */ diff --git a/lib/efi_loader/Kconfig b/lib/efi_loader/Kconfig index 3dadbc54b58..077466f01f0 100644 --- a/lib/efi_loader/Kconfig +++ b/lib/efi_loader/Kconfig @@ -71,6 +71,15 @@ config EFI_SECURE_BOOT config EFI_SIGNATURE_SUPPORT bool +config EFI_DEBUG_SUPPORT + bool "EFI Debug Support" + default y if !HAS_BOARD_SIZE_LIMIT + help + Select this option if you want to setup the EFI Debug Support + Table and the EFI_SYSTEM_TABLE_POINTER which is used by the debug + agent or an external debugger to determine loaded image information + in a quiescent manner. + menu "UEFI services" config EFI_GET_TIME diff --git a/lib/efi_loader/Makefile b/lib/efi_loader/Makefile index cf050e5385d..51ccf1cd87e 100644 --- a/lib/efi_loader/Makefile +++ b/lib/efi_loader/Makefile @@ -70,6 +70,7 @@ obj-$(CONFIG_EFI_RISCV_BOOT_PROTOCOL) += efi_riscv.o obj-$(CONFIG_EFI_LOAD_FILE2_INITRD) += efi_load_initrd.o obj-$(CONFIG_EFI_SIGNATURE_SUPPORT) += efi_signature.o obj-$(CONFIG_EFI_ECPT) += efi_conformance.o +obj-$(CONFIG_EFI_DEBUG_SUPPORT) += efi_debug_support.o EFI_VAR_SEED_FILE := $(subst $\",,$(CONFIG_EFI_VAR_SEED_FILE)) $(obj)/efi_var_seed.o: $(srctree)/$(EFI_VAR_SEED_FILE) diff --git a/lib/efi_loader/efi_debug_support.c b/lib/efi_loader/efi_debug_support.c new file mode 100644 index 00000000000..649d21ef829 --- /dev/null +++ b/lib/efi_loader/efi_debug_support.c @@ -0,0 +1,40 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * EFI debug support + * + * Copyright (c) 2025 Ying-Chun Liu, Linaro Ltd. + */ + +#include +#include +#include + +struct efi_system_table_pointer __efi_runtime_data * systab_pointer = NULL; + +/** + * efi_initialize_system_table_pointer() - Initialize system table pointer + * + * Return: status code + */ +efi_status_t efi_initialize_system_table_pointer(void) +{ + /* Allocate efi_system_table_pointer structure with 4MB alignment. */ + systab_pointer = efi_alloc_aligned_pages(sizeof(struct efi_system_table_pointer), + EFI_RUNTIME_SERVICES_DATA, + SZ_4M); + + if (!systab_pointer) { + log_err("Installing EFI system table pointer failed\n"); + return EFI_OUT_OF_RESOURCES; + } + + systab_pointer->crc32 = 0; + + systab_pointer->signature = EFI_SYSTEM_TABLE_SIGNATURE; + systab_pointer->efi_system_table_base = (uintptr_t)&systab; + systab_pointer->crc32 = crc32(0, + (const unsigned char *)systab_pointer, + sizeof(struct efi_system_table_pointer)); + + return EFI_SUCCESS; +} diff --git a/lib/efi_loader/efi_setup.c b/lib/efi_loader/efi_setup.c index 48f91da5df7..78c5059256a 100644 --- a/lib/efi_loader/efi_setup.c +++ b/lib/efi_loader/efi_setup.c @@ -278,6 +278,13 @@ efi_status_t efi_init_obj_list(void) if (ret != EFI_SUCCESS) goto out; + /* Initialize system table pointer */ + if (IS_ENABLED(CONFIG_EFI_DEBUG_SUPPORT)) { + ret = efi_initialize_system_table_pointer(); + if (ret != EFI_SUCCESS) + goto out; + } + if (IS_ENABLED(CONFIG_EFI_ECPT)) { ret = efi_ecpt_register(); if (ret != EFI_SUCCESS)