support booting EFI application on x86_64 architecture

Co-authored-by: Daniele Lacamera <daniele@wolfssl.com>

.gitignore

@@ -37,6 +37,7 @@
 *.hex
 *.rom
 *.bin
+*.efi
 
 # Debug files
 *.dSYM/

Makefile

@@ -39,10 +39,12 @@ CFLAGS+= \
   -D"PLATFORM_$(TARGET)"
 
 # Setup default optimizations (for GCC)
-ifeq ($(USE_GCC),1)
+ifneq ($(TARGET),x86_64_efi)
+  ifeq ($(USE_GCC),1)
     CFLAGS+=-Wall -Wextra -Wno-main -ffreestanding -Wno-unused -nostartfiles
     CFLAGS+=-ffunction-sections -fdata-sections
     LDFLAGS+=-T $(LSCRIPT) -Wl,-gc-sections -Wl,-Map=wolfboot.map -ffreestanding -nostartfiles
+  endif
 endif
 
 MAIN_TARGET=factory.bin
@@ -52,12 +54,27 @@ ifeq ($(TARGET),stm32l5)
 	MAIN_TARGET:=wolfboot.bin test-app/image_v1_signed.bin
 endif
 
+ifeq ($(TARGET),x86_64_efi)
+	MAIN_TARGET:=wolfboot.efi
+endif
+
 ASFLAGS:=$(CFLAGS)
 
 BOOTLOADER_PARTITION_SIZE?=$$(( $(WOLFBOOT_PARTITION_BOOT_ADDRESS) - $(ARCH_FLASH_OFFSET)))
 
 all: $(MAIN_TARGET)
 
+wolfboot.efi: wolfboot.elf
+	@echo "\t[BIN] $@"
+	$(Q)$(OBJCOPY)  -j .text -j .sdata -j .data \
+                -j .dynamic -j .dynsym  -j .rel \
+                -j .rela -j .reloc -j .eh_frame \
+                --target=efi-app-x86_64 --subsystem=10 $^ $@
+	@echo
+	@echo "\t[SIZE]"
+	$(Q)$(SIZE) wolfboot.efi
+	@echo
+
 wolfboot.bin: wolfboot.elf
 	@echo "\t[BIN] $@"
 	$(Q)$(OBJCOPY) -O binary $^ $@

arch.mk

@@ -21,6 +21,13 @@ UART_TARGET=$(TARGET)
 # Include SHA256 module because it's implicitly needed by RSA
 WOLFCRYPT_OBJS+=./lib/wolfssl/wolfcrypt/src/sha256.o
 
+ifeq ($(ARCH),x86_64)
+  OBJS+=src/boot_x86_64.o
+  ifeq ($(DEBUG),1)
+    CFLAGS+=-DWOLFBOOT_DEBUG_EFI=1
+  endif
+endif
+
 ## ARM
 ifeq ($(ARCH),AARCH64)
   CROSS_COMPILE:=aarch64-none-elf-
@@ -299,6 +306,21 @@ ifeq ($(USE_GCC),1)
   OUTPUT_FLAG=-o
 endif
 
+
+ifeq ($(TARGET),x86_64_efi)
+  GNU_EFI_LIB_PATH?=/usr/lib
+  GNU_EFI_CRT0=$(GNU_EFI_LIB_PATH)/crt0-efi-x86_64.o
+  GNU_EFI_LSCRIPT=$(GNU_EFI_LIB_PATH)/elf_x86_64_efi.lds
+  CFLAGS += -fpic -ffreestanding -fno-stack-protector -fno-stack-check \
+            -fshort-wchar -mno-red-zone -maccumulate-outgoing-args
+  CFLAGS += -I/usr/include/efi -DPLATFORM_X86_64_EFI
+  LDFLAGS = -shared -Bsymbolic -L/usr/lib -T$(GNU_EFI_LSCRIPT)
+  LD_START_GROUP = $(GNU_EFI_CRT0)
+  LD_END_GROUP = -lgnuefi -lefi
+  LD = ld
+  UPDATE_OBJS:=src/update_ram.o
+endif
+
 BOOT_IMG?=test-app/image.bin
 
 ## Update mechanism

config/examples/x86_64_efi.config

@@ -0,0 +1,8 @@
+ARCH=x86_64
+TARGET=x86_64_efi
+WOLFBOOT_SMALL_STACK=1
+SIGN?=ED25519
+HASH?=SHA256
+IMAGE_HEADER_SIZE?=0x100
+DEBUG=0
+SPMATH=0

docs/Targets.md

@@ -21,6 +21,7 @@ This README describes configuration of supported targets.
 * [STM32WB55](#stm32wb55)
 * [TI Hercules TMS570LC435](#ti-hercules-tms570lc435)
 * [Xilinx Zynq UltraScale](#xilinx-zynq-ultrascale)
+* [Qemu x86_64 UEFI](#qemu-x86_64-uefi)
 
 ## STM32F4
 
@@ -930,3 +931,52 @@ to compile.
 ## TI Hercules TMS570LC435
 
 See [/config/examples/ti-tms570lc435.config](/config/examples/ti-tms570lc435.config) for example configuration.
+
+
+## Qemu x86-64 UEFI
+
+x86-64bit machine with UEFI bios can run wolfBoot as EFI application.
+
+### Prerequisites:
+
+ * qemu-system-x86_64
+ * [GNU-EFI] (https://sourceforge.net/projects/gnu-efi/) 
+ * Open Virtual Machine firmware bios images (OVMF) by [Tianocore](https://tianocore.org)
+
+On a debian-like system it is sufficient to install the packages as follows:
+
+`apt install qemu ovmf gnu-efi`
+
+### Configuration
+
+An example configuration is provided in [config/examples/x86_64_efi.config](config/examples/x86_64_efi.config)
+
+### Building and running on qemu
+
+The bootloader and the initialization script `startup.nsh` for execution in the EFI environment are stored in a loopback FAT partition.
+
+The script [tools/efi/prepare_uefi_partition.sh](tools/efi/prepare_uefi_partition.sh) creates a new empty
+FAT loopback partitions and adds `startup.nsh`.
+
+A kernel with an embedded rootfs partition can be now created and added to the image, via the
+script [tools/efi/compile_efi_linux.sh](tools/efi/compile_efi_linux.sh). The script actually adds two instances
+of the target systems: `kernel.img` and `update.img`, both signed for authentication, and tagged with version
+`1` and `2` respectively.
+
+Compiling with `make` will produce the bootloader image in `wolfboot.efi`.
+
+
+The script [tools/efi/run_efi.sh](tools/efi/run_efi.sh) will add `wolfboot.efi` to the bootloader loopback
+partition, and run the system on qemu. If both kernel images are present and valid, wolfBoot will choose the image
+with the higher version number, so `update.img` will be staged as it's tagged with version `2`.
+
+The sequence is summarized below:
+
+```
+cp config/examples/x86_64_efi.config .config
+tools/efi/prepare_efi_partition.sh
+make
+tools/efi/compile_efi_linux.sh
+tools/efi/run_efi.sh
+```
+

hal/x86_64_efi.c

@@ -0,0 +1,258 @@
+
+/* x86_64_efi.c
+ *
+ * Copyright (C) 2021 wolfSSL Inc.
+ *
+ * This file is part of wolfBoot.
+ *
+ * wolfBoot is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * wolfBoot is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335, USA
+ */
+
+#include <stdint.h>
+#include <target.h>
+
+#include "image.h"
+#include "loader.h"
+#include "printf.h"
+
+#ifdef PLATFORM_X86_64_EFI
+
+#include <efi/efi.h>
+#include <efi/efilib.h>
+
+#ifdef __WOLFBOOT
+void hal_init(void)
+{
+}
+
+void hal_prepare_boot(void)
+{
+}
+
+#endif
+
+#define PAGE_SIZE 0x1000
+#define EFI_DEVICE_PATH_PROTOCOL_HW_TYPE 0x01
+#define EFI_DEVICE_PATH_PROTOCOL_MEM_SUBTYPE 0x03
+
+static EFI_SYSTEM_TABLE *gSystemTable;
+static EFI_HANDLE *gImageHandle;
+EFI_PHYSICAL_ADDRESS kernel_addr;
+EFI_PHYSICAL_ADDRESS update_addr;
+
+int RAMFUNCTION hal_flash_write(uint32_t address, const uint8_t *data, int len)
+{
+    return 0;
+}
+
+void RAMFUNCTION hal_flash_unlock(void)
+{
+}
+
+void RAMFUNCTION hal_flash_lock(void)
+{
+}
+
+int RAMFUNCTION hal_flash_erase(uint32_t address, int len)
+{
+    return 0;
+}
+
+static void panic()
+{
+    while(1) {}
+}
+
+void RAMFUNCTION x86_64_efi_do_boot(uint8_t *kernel)
+{
+    MEMMAP_DEVICE_PATH mem_path_device[2];
+    EFI_HANDLE kernelImageHandle;
+    EFI_STATUS status;
+    uint32_t *size;
+
+    size = (uint32_t *)(kernel + 4);
+    kernel += IMAGE_HEADER_SIZE;
+
+    mem_path_device->Header.Type = EFI_DEVICE_PATH_PROTOCOL_HW_TYPE;
+    mem_path_device->Header.SubType = EFI_DEVICE_PATH_PROTOCOL_MEM_SUBTYPE;
+    mem_path_device->MemoryType = EfiLoaderData;
+    mem_path_device->StartingAddress = (EFI_PHYSICAL_ADDRESS)kernel;
+    mem_path_device->EndingAddress = (EFI_PHYSICAL_ADDRESS)(kernel+*size);
+    SetDevicePathNodeLength(&mem_path_device->Header,
+                            sizeof(MEMMAP_DEVICE_PATH));
+
+    SetDevicePathEndNode(&mem_path_device[1].Header);
+
+    wolfBoot_printf("Staging kernel at address %x, size: %u\n", kernel, *size);
+    status = uefi_call_wrapper(gSystemTable->BootServices->LoadImage,
+                               6,
+                               0, /* bool */
+                               gImageHandle,
+                               (EFI_DEVICE_PATH*)mem_path_device,
+                               kernel,
+                               *size,
+                               &kernelImageHandle);
+    if (status != EFI_SUCCESS) {
+        wolfBoot_printf("can't load kernel image from memory\n");
+        panic();
+    }
+
+    status = uefi_call_wrapper(gSystemTable->BootServices->StartImage,
+                               3,
+                               kernelImageHandle, 0, NULL);
+    if (status != EFI_SUCCESS) {
+        wolfBoot_printf("can't load kernel image from memory\n");
+        panic();
+    }
+}
+
+static UINT64 FileSize(EFI_FILE_HANDLE FileHandle)
+{
+    EFI_FILE_INFO *FileInfo;
+    UINT64 ret;
+
+    FileInfo = LibFileInfo(FileHandle);
+    if (FileInfo == NULL)
+        panic();
+
+    ret = FileInfo->FileSize;
+    FreePool(FileInfo);
+
+    return ret;
+}
+
+static EFI_FILE_HANDLE GetVolume(EFI_HANDLE image)
+{
+    EFI_GUID fsGuid = EFI_SIMPLE_FILE_SYSTEM_PROTOCOL_GUID;
+    EFI_GUID lipGuid = EFI_LOADED_IMAGE_PROTOCOL_GUID;
+    EFI_LOADED_IMAGE *loaded_image = NULL;
+    EFI_FILE_IO_INTERFACE *IOVolume;
+    EFI_FILE_HANDLE Volume;
+    EFI_STATUS status;
+
+    status = uefi_call_wrapper(BS->HandleProtocol, 3,
+                               image, &lipGuid, (void **) &loaded_image);
+    if (status != EFI_SUCCESS)
+        panic();
+
+    status = uefi_call_wrapper(BS->HandleProtocol, 3,
+                               loaded_image->DeviceHandle,
+                               &fsGuid, (VOID*)&IOVolume);
+    if (status != EFI_SUCCESS)
+        panic();
+
+    status = uefi_call_wrapper(IOVolume->OpenVolume, 2, IOVolume, &Volume);
+
+    if (status != EFI_SUCCESS)
+        panic();
+
+    return Volume;
+}
+
+static EFI_FILE_HANDLE openFile(CHAR16 *file, EFI_FILE_HANDLE volume)
+{
+    EFI_FILE_HANDLE file_handle;
+    EFI_STATUS status;
+
+    status = uefi_call_wrapper(volume->Open, 5,
+                               volume,
+                               &file_handle,
+                               file,
+                               EFI_FILE_MODE_READ,
+                               EFI_FILE_READ_ONLY | EFI_FILE_HIDDEN | EFI_FILE_SYSTEM);
+
+    if (status != EFI_SUCCESS)
+        file_handle = NULL;
+
+    return file_handle;
+}
+
+static int open_kernel_image(EFI_FILE_HANDLE vol, CHAR16 *filename,
+        EFI_PHYSICAL_ADDRESS *_addr, uint32_t *sz)
+{
+    EFI_FILE_HANDLE file;
+    EFI_STATUS status;
+
+    file = openFile(filename, vol);
+    if (file == NULL)
+        return -1;
+
+    *sz =  FileSize(file);
+    wolfBoot_printf("Opening file: %s, size: %u\n", filename, *sz);
+    status = uefi_call_wrapper(BS->AllocatePages,
+                          4,
+                          AllocateAnyPages,
+                          EfiLoaderData,
+                          (*sz/PAGE_SIZE) + 1, _addr);
+    if (status != EFI_SUCCESS) {
+        wolfBoot_printf("can't get memory at specified address %d\n", status);
+        return status;
+    }
+
+    status = uefi_call_wrapper(file->Read, 3, file, sz, *_addr);
+    if (status != EFI_SUCCESS) {
+        wolfBoot_printf("can't read kernel image %d\n", status);
+        return status;
+    }
+
+    if (*sz < IMAGE_HEADER_SIZE) {
+        wolfBoot_printf("Image smaller than the header\n");
+        return -1;
+    }
+
+    return 0;
+}
+
+EFI_STATUS
+EFIAPI
+efi_main (EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE *SystemTable)
+{
+    CHAR16 *kernel_filename = L"kernel.img";
+    CHAR16 *update_filename = L"update.img";
+    EFI_LOADED_IMAGE *loaded_image = NULL;
+    EFI_FILE_HANDLE vol;
+    EFI_STATUS status;
+    uint8_t *mem;
+    UINT64 size;
+    UINT64 r;
+    uint32_t kernel_size, update_size;
+
+    InitializeLib(ImageHandle, SystemTable);
+    gSystemTable = SystemTable;
+    gImageHandle = ImageHandle;
+
+    status = uefi_call_wrapper(SystemTable->BootServices->HandleProtocol,
+                               3,
+                               ImageHandle,
+                               &LoadedImageProtocol,
+                               (void **)&loaded_image);
+
+    if (status == EFI_SUCCESS)
+        wolfBoot_printf("Image base: 0x%lx\n", loaded_image->ImageBase);
+    vol = GetVolume(ImageHandle);
+    open_kernel_image(vol, kernel_filename, &kernel_addr, &kernel_size);
+    open_kernel_image(vol, update_filename, &update_addr, &update_size);
+
+    if (kernel_addr == 0 && update_addr == 0) {
+        wolfBoot_printf("No image to load\n");
+        panic();
+    }
+
+    wolfBoot_start();
+
+    return EFI_SUCCESS;
+}
+
+#endif /* PLATFORM_X86_64_EFI */

hal/x86_64_efi.ld

@@ -0,0 +1 @@
+# efi target uses the linker script provided by gnu-efi. This is an empty file to appease Makefile.

include/printf.h

@@ -28,11 +28,18 @@
 #    define PRINTF_ENABLED
 #endif
 
+#if defined(WOLFBOOT_DEBUG_EFI) && !defined(PRINTF_ENABLED)
+#    define PRINTF_ENABLED
+#endif
+
 #ifdef PRINTF_ENABLED
 #   include <stdio.h>
 #   if defined(DEBUG_ZYNQ) && !defined(USE_QNX)
 #       include "xil_printf.h"
 #       define wolfBoot_printf(_f_, ...) xil_printf(_f_, ##__VA_ARGS__)
+#   elif defined(WOLFBOOT_DEBUG_EFI)
+        /* NOTE: %s arguments will not work as EFI uses widechar string */
+#       define wolfBoot_printf(_f_, ...) Print(L##_f_, ##__VA_ARGS__)
 #   else
 #       define wolfBoot_printf(_f_, ...) printf(_f_, ##__VA_ARGS__)
 #   endif

include/target.h.in

@@ -27,16 +27,27 @@
 #ifndef H_TARGETS_TARGET_
 #define H_TARGETS_TARGET_
 
-#define WOLFBOOT_SECTOR_SIZE                 ##WOLFBOOT_SECTOR_SIZE##
-#define WOLFBOOT_PARTITION_BOOT_ADDRESS      ##WOLFBOOT_PARTITION_BOOT_ADDRESS##
-#define WOLFBOOT_PARTITION_SIZE              ##WOLFBOOT_PARTITION_SIZE##
-#define WOLFBOOT_PARTITION_UPDATE_ADDRESS    ##WOLFBOOT_PARTITION_UPDATE_ADDRESS##
-#define WOLFBOOT_PARTITION_SWAP_ADDRESS      ##WOLFBOOT_PARTITION_SWAP_ADDRESS##
+#ifndef PLATFORM_X86_64_EFI
+    #define WOLFBOOT_SECTOR_SIZE                 ##WOLFBOOT_SECTOR_SIZE##
+    #define WOLFBOOT_PARTITION_BOOT_ADDRESS      ##WOLFBOOT_PARTITION_BOOT_ADDRESS##
+    #define WOLFBOOT_PARTITION_SIZE              ##WOLFBOOT_PARTITION_SIZE##
+    #define WOLFBOOT_PARTITION_UPDATE_ADDRESS    ##WOLFBOOT_PARTITION_UPDATE_ADDRESS##
+    #define WOLFBOOT_PARTITION_SWAP_ADDRESS      ##WOLFBOOT_PARTITION_SWAP_ADDRESS##
 
-/* Load address in RAM for staged OS (update_ram only) */
-#define WOLFBOOT_DTS_BOOT_ADDRESS            ##WOLFBOOT_DTS_BOOT_ADDRESS##
-#define WOLFBOOT_DTS_UPDATE_ADDRESS          ##WOLFBOOT_DTS_UPDATE_ADDRESS##
-#define WOLFBOOT_LOAD_ADDRESS                ##WOLFBOOT_LOAD_ADDRESS##
-#define WOLFBOOT_LOAD_DTS_ADDRESS            ##WOLFBOOT_LOAD_DTS_ADDRESS##
+    /* Load address in RAM for staged OS (update_ram only) */
+    #define WOLFBOOT_DTS_BOOT_ADDRESS            ##WOLFBOOT_DTS_BOOT_ADDRESS##
+    #define WOLFBOOT_DTS_UPDATE_ADDRESS          ##WOLFBOOT_DTS_UPDATE_ADDRESS##
+    #define WOLFBOOT_LOAD_ADDRESS                ##WOLFBOOT_LOAD_ADDRESS##
+    #define WOLFBOOT_LOAD_DTS_ADDRESS            ##WOLFBOOT_LOAD_DTS_ADDRESS##
+#else
+    #include "efi/efi.h"
+    extern EFI_PHYSICAL_ADDRESS kernel_addr;
+    extern EFI_PHYSICAL_ADDRESS update_addr;
+    #define WOLFBOOT_PARTITION_BOOT_ADDRESS (kernel_addr)
+    #define WOLFBOOT_PARTITION_UPDATE_ADDRESS (update_addr)
+    #define WOLFBOOT_PARTITION_SWAP_ADDRESS 0
+    #define WOLFBOOT_SECTOR_SIZE 0x1000
+    #define WOLFBOOT_PARTITION_SIZE (2 * 1024 * 1024 * 1024ULL)
+#endif
 
 #endif /* !H_TARGETS_TARGET_ */

options.mk

@@ -185,7 +185,7 @@ endif
 
 
 ifeq ($(DEBUG),1)
-  CFLAGS+=-O0 -g -ggdb3 -D"DEBUG=1"
+  CFLAGS+=-O0 -g -ggdb3
 else
   ifeq ($(OPTIMIZATION_LEVEL),)
     CFLAGS+=-Os
@@ -247,6 +247,9 @@ ifeq ($(WOLFTPM),1)
   endif
   WOLFCRYPT_OBJS+=./lib/wolfssl/wolfcrypt/src/aes.o
   WOLFCRYPT_OBJS+=./lib/wolfssl/wolfcrypt/src/hmac.o
+  ifeq ($(DEBUG),1)
+    CFLAGS+=-DWOLFBOOT_DEBUG_TPM=1
+  endif
 endif
 
 ## Hash settings

src/boot_x86_64.c

@@ -0,0 +1,48 @@
+/* boot_x86_64.c
+ *
+ * Copyright (C) 2021 wolfSSL Inc.
+ *
+ * This file is part of wolfBoot.
+ *
+ * wolfBoot is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * wolfBoot is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335, USA
+ */
+#include <stdint.h>
+
+#include "image.h"
+#include "loader.h"
+#include "wolfboot/wolfboot.h"
+
+#ifdef PLATFORM_X86_64_EFI
+
+#include <efi/efi.h>
+#include <efi/efilib.h>
+
+extern unsigned int __bss_start__;
+extern unsigned int __bss_end__;
+static volatile unsigned int cpu_id;
+extern unsigned int *END_STACK;
+
+extern void RAMFUNCTION x86_64_efi_do_boot(uint8_t *kernel);
+
+#ifdef MMU
+void RAMFUNCTION do_boot(const uint32_t *app_offset, const uint32_t* dts_offset)
+#else
+void RAMFUNCTION do_boot(const uint32_t *app_offset)
+#endif
+{
+    x86_64_efi_do_boot((uint8_t *)app_offset);
+}
+
+#endif /* PLATFORM_X86_64_EFI */

src/image.c

@@ -69,7 +69,7 @@ static int wolfBoot_verify_signature(uint8_t *hash, uint8_t *sig)
     int ret, verify_res = 0;
 #ifdef WOLFBOOT_TPM
     WOLFTPM2_KEY tpmKey;
-    #ifdef DEBUG
+    #ifdef WOLFBOOT_DEBUG_TPM
     const char* errStr;
     #endif
 
@@ -87,7 +87,7 @@ static int wolfBoot_verify_signature(uint8_t *hash, uint8_t *sig)
         verify_res = 1; /* TPM does hash verify compare */
     }
     else {
-    #ifdef DEBUG
+    #ifdef WOLFBOOT_DEBUG_TPM
         /* retrieve error string (for debugging) */
         errStr = wolfTPM2_GetRCString(ret);
         (void)errStr;
@@ -212,7 +212,7 @@ static int wolfBoot_verify_signature(uint8_t *hash, uint8_t *sig)
     WOLFTPM2_KEY tpmKey;
     const byte *n = NULL, *e = NULL;
     word32 nSz = 0, eSz = 0, inOutIdx = 0;
-    #ifdef DEBUG
+    #ifdef WOLFBOOT_DEBUG_TPM
         const char* errStr;
     #endif
 
@@ -226,7 +226,7 @@ static int wolfBoot_verify_signature(uint8_t *hash, uint8_t *sig)
     ret = wolfTPM2_LoadRsaPublicKey_ex(&wolftpm_dev, &tpmKey, n, nSz, 
         *((word32*)e), TPM_ALG_NULL, TPM_ALG_SHA256);
     if (ret != 0) {
-    #ifdef DEBUG
+    #ifdef WOLFBOOT_DEBUG_TPM
         /* retrieve error string (for debugging) */
         errStr = wolfTPM2_GetRCString(ret);
         (void)errStr;
@@ -240,7 +240,7 @@ static int wolfBoot_verify_signature(uint8_t *hash, uint8_t *sig)
         sig, IMAGE_SIGNATURE_SIZE,
         output, &output_sz);
     if (ret != 0) {
-    #ifdef DEBUG
+    #ifdef WOLFBOOT_DEBUG_TPM
         /* retrieve error string (for debugging) */
         errStr = wolfTPM2_GetRCString(ret);
         (void)errStr;
@@ -564,7 +564,7 @@ static int measure_boot(uint8_t *hash)
 {
     int rc = -1;
     PCR_Extend_In pcrExtend;
-#ifdef DEBUG
+#ifdef WOLFBOOT_DEBUG_TPM
     PCR_Read_In pcrReadCmd;
     PCR_Read_Out pcrReadResp;
 #endif
@@ -580,7 +580,7 @@ static int measure_boot(uint8_t *hash)
         rc = 0;
     }
 
-#ifdef DEBUG
+#ifdef WOLFBOOT_DEBUG_TPM
     /* Test prcRead helps debug TPM communication and print PCR value in gdb */
     XMEMSET(&pcrReadCmd, 0, sizeof(pcrReadCmd));
     TPM2_SetupPCRSel(&pcrReadCmd.pcrSelectionIn, TPM_ALG_SHA256,

src/libwolfboot.c

@@ -646,7 +646,8 @@ uint16_t wolfBoot_get_image_type(uint8_t part)
     return 0;
 }
 
-#if defined(ARCH_AARCH64) || defined(DUALBANK_SWAP)
+#if defined(ARCH_AARCH64) || defined(DUALBANK_SWAP) || defined(PLATFORM_X86_64_EFI)
+
 int wolfBoot_fallback_is_possible(void)
 {
     uint32_t boot_v, update_v;

src/string.c

@@ -51,7 +51,7 @@ int isalpha(int c)
     return (isupper(c) || islower(c));
 }
 
-#ifndef __IAR_SYSTEMS_ICC__
+#if !defined(__IAR_SYSTEMS_ICC__) && !defined(PLATFORM_X86_64_EFI)
 void *memset(void *s, int c, size_t n)
 {
 	unsigned char *d = (unsigned char *)s;
@@ -168,7 +168,7 @@ int strncmp(const char *s1, const char *s2, size_t n)
     return diff;
 }
 
-#ifndef __IAR_SYSTEMS_ICC__
+#if  !defined(__IAR_SYSTEMS_ICC__) && !defined(PLATFORM_X86_64_EFI)
 void *memcpy(void *dst, const void *src, size_t n)
 {
     size_t i;

src/update_ram.c

@@ -30,6 +30,13 @@
 #include "wolfboot/wolfboot.h"
 #include <string.h>
 
+#ifdef PLATFORM_X86_64_EFI
+    #include "efi/efi.h"
+    #include "efi/efilib.h"
+    extern EFI_PHYSICAL_ADDRESS kernel_addr;
+    extern EFI_PHYSICAL_ADDRESS update_addr;
+#endif
+
 extern void hal_flash_dualbank_swap(void);
 
 static inline void boot_panic(void)
@@ -42,7 +49,12 @@ void RAMFUNCTION wolfBoot_start(void)
 {
     int active, ret = 0;
     struct wolfBoot_image os_image;
+#ifdef PLATFORM_X86_64_EFI
+    uint32_t* load_address = (uint32_t*)kernel_addr;
+#else
     uint32_t* load_address = (uint32_t*)WOLFBOOT_LOAD_ADDRESS;
+#endif
+
     uint8_t* image_ptr;
     uint8_t p_state;
 #ifdef MMU
@@ -56,6 +68,11 @@ void RAMFUNCTION wolfBoot_start(void)
     if (active < 0) /* panic if no images available */
         boot_panic();
 
+#ifdef PLATFORM_X86_64_EFI
+    if (active == 1)
+        load_address = (uint32_t *)update_addr;
+#endif
+
     /* Check current status for failure (image still in TESTING), and fall-back
      * if an alternative is available
      */
@@ -143,11 +160,14 @@ void RAMFUNCTION wolfBoot_start(void)
     }
 #endif
 
-    hal_prepare_boot();
 	
     wolfBoot_printf("Booting at %08lx\n", load_address);
+    hal_prepare_boot();
 
-#ifdef MMU
+#ifdef PLATFORM_X86_64_EFI
+    extern void x86_64_efi_do_boot(uint8_t *);
+    x86_64_efi_do_boot((uint8_t*)load_address);
+#elif defined MMU
     do_boot((uint32_t*)load_address, (uint32_t*)dts_address);
 #else
     do_boot((uint32_t*)load_address);

tools/efi/br_ext_dir/configs/tiny_defconfig

@@ -0,0 +1,14 @@
+BR2_x86_64=y
+BR2_x86_corei7=y
+# BR2_STRIP_strip is not set
+# BR2_COMPILER_PARANOID_UNSAFE_PATH is not set
+BR2_TOOLCHAIN_EXTERNAL=y
+# BR2_TARGET_GENERIC_REMOUNT_ROOTFS_RW is not set
+# BR2_ENABLE_LOCALE_PURGE is not set
+BR2_LINUX_KERNEL=y
+BR2_LINUX_KERNEL_USE_CUSTOM_CONFIG=y
+BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE="$(BR2_EXTERNAL_TINY_PATH)/linux.config"
+# BR2_PACKAGE_IFUPDOWN_SCRIPTS is not set
+# BR2_PACKAGE_URANDOM_SCRIPTS is not set
+BR2_TARGET_ROOTFS_INITRAMFS=y
+# BR2_TARGET_ROOTFS_TAR is not set

tools/efi/br_ext_dir/external.desc

@@ -0,0 +1,2 @@
+name: TINY
+desc: configuration for building a tiny kernel+initramfs image

tools/efi/br_ext_dir/linux.config

@@ -0,0 +1,31 @@
+CONFIG_BLK_DEV_INITRD=y
+CONFIG_INITRAMFS_SOURCE="${BR_BINARIES_DIR}/rootfs.cpio"
+CONFIG_EXPERT=y
+CONFIG_EFI=y
+CONFIG_EFI_STUB=y
+CONFIG_CMDLINE_BOOL=y
+CONFIG_CMDLINE="console=ttyS0"
+# CONFIG_EFI_CUSTOM_SSDT_OVERLAYS is not set
+# CONFIG_GCC_PLUGINS is not set
+# CONFIG_BLOCK is not set
+CONFIG_PCI=y
+CONFIG_PCIEPORTBUS=y
+CONFIG_DEVTMPFS=y
+CONFIG_DEVTMPFS_MOUNT=y
+CONFIG_SERIAL_8250=y
+CONFIG_SERIAL_8250_CONSOLE=y
+CONFIG_TTY_PRINTK=y
+CONFIG_TCG_TPM=y
+CONFIG_TCG_TIS=y
+CONFIG_TCG_TIS_SPI=y
+CONFIG_TCG_TIS_SPI_CR50=y
+CONFIG_TCG_NSC=y
+CONFIG_TCG_ATMEL=y
+CONFIG_TCG_INFINEON=y
+CONFIG_TCG_CRB=y
+CONFIG_TCG_VTPM_PROXY=y
+CONFIG_TCG_TIS_ST33ZP24_SPI=y
+CONFIG_SPI=y
+# CONFIG_SECURITYFS is not set
+CONFIG_CRYPTO_SHA1=y
+CONFIG_UNWINDER_GUESS=y

tools/efi/compile_efi_linux.sh

@@ -0,0 +1,35 @@
+#!/bin/sh
+
+WORK_DIR=/tmp/wolfBoot_efi
+BR_VER=2021.08.2
+BR_DIR=buildroot-$BR_VER
+IMAGE_DIR=$WORK_DIR/output
+
+if (test ! -d $WORK_DIR);then
+    mkdir -p $WORK_DIR
+fi
+
+if (test ! -d $WORK_DIR/$BR_DIR);then
+    curl https://buildroot.org/downloads/$BR_DIR.tar.gz -o $WORK_DIR/$BR_DIR.tar.gz
+    tar xvf $WORK_DIR/$BR_DIR.tar.gz -C $WORK_DIR
+fi
+
+BR2_EXTERNAL=$(pwd)/tools/efi/br_ext_dir make -C $WORK_DIR/$BR_DIR tiny_defconfig O=$IMAGE_DIR
+make -C $WORK_DIR/$BR_DIR O=$IMAGE_DIR
+
+SIGN_TOOL="python3 ./tools/keytools/sign.py"
+if [ -f "./tools/keytools/sign" ]; then
+    SIGN_TOOL="./tools/keytools/sign"
+fi
+
+$SIGN_TOOL --ed25519 $IMAGE_DIR/images/bzImage ed25519.der 1
+$SIGN_TOOL --ed25519 $IMAGE_DIR/images/bzImage ed25519.der 2
+
+mkdir -p /tmp/efi
+sudo mount /tmp/efi.disk /tmp/efi
+sudo cp $IMAGE_DIR/images/bzImage_v1_signed.bin /tmp/efi/kernel.img
+sudo cp $IMAGE_DIR/images/bzImage_v2_signed.bin /tmp/efi/update.img
+sudo cp wolfboot.efi /tmp/efi
+sudo umount /tmp/efi
+
+

tools/efi/prepare_efi_partition.sh

@@ -0,0 +1,14 @@
+#!/bin/sh
+
+dd if=/dev/zero of=/tmp/efi.disk bs=256M count=1
+sudo mkfs.vfat /tmp/efi.disk
+mkdir -p /tmp/efi
+sudo mount /tmp/efi.disk /tmp/efi -oloop
+cat <<EOF > /tmp/startup.nsh
+@echo -off
+echo Starting wolfBoot EFI...
+fs0:
+wolfboot.efi
+EOF
+sudo mv /tmp/startup.nsh /tmp/efi/ 2>/dev/null
+sudo umount /tmp/efi

tools/efi/run_efi.sh

@@ -0,0 +1,50 @@
+#!/bin/sh
+
+## TPM emulator:
+# https://github.com/stefanberger/swtpm
+
+if (test -z $OVMF_PATH); then
+    if (test -f /usr/share/edk2-ovmf/x64/OVMF.fd); then
+        OVMF_PATH=/usr/share/edk2-ovmf/x64
+    elif (test -f /usr/share/qemu/OVMF.fd); then
+        OVMF_PATH=/usr/share/qemu
+    else
+        OVMF_PATH=/
+    fi
+fi
+
+QEMU_OPTIONS=" \
+    -m 256M \
+    -net none \
+    -bios ${OVMF_PATH}/OVMF.fd \
+    -drive file=/tmp/efi.disk,index=0,media=disk,format=raw \
+    -vga none \
+    -serial stdio \
+    -display none"
+
+
+QEMU_TPM_OPTIONS=" \
+    -chardev socket,id=chrtpm,path=/tmp/swtpm/swtpm-sock \
+    -tpmdev emulator,id=tpm0,chardev=chrtpm \
+    -device tpm-tis,tpmdev=tpm0"
+
+if (which swtpm); then
+    killall swtpm
+    sleep 1
+    QEMU_EXTRA=$QEMU_TPM_OPTIONS
+    echo TPM Emulation ON
+    mkdir -p /tmp/swtpm
+    swtpm socket --tpm2 --tpmstate dir=/tmp/swtpm \
+        --ctrl type=unixio,path=/tmp/swtpm/swtpm-sock --log level=20 &
+else
+    echo TPM Emulation OFF
+fi
+
+mkdir -p /tmp/efi
+sudo mount /tmp/efi.disk /tmp/efi
+sudo cp wolfboot.efi /tmp/efi
+sudo umount /tmp/efi
+
+echo $QEMU_OPTIONS $QEMU_EXTRA
+
+qemu-system-x86_64 $QEMU_OPTIONS $QEMU_EXTRA