boot_x86_fsp_payload.c

/* boot_x86_fsp_payload.c
 *
 * Copyright (C) 2026 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 3 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
 */
/**
 * @file boot_x86_fsp_payload.c
 *
 * @brief Boot functions for x86 FSP payload
 *
 * This file contains the boot functions for the x86 FSP payload of wolfBoot.
 * These functions include booting into Linux payload or ELF binaries.
 */
#ifndef BOOT_X86_FSP_PAYLOAD_H_
#define BOOT_X86_FSP_PAYLOAD_H_

#include <stdint.h>
#include <string.h>
#include <x86/common.h>

#include <printf.h>
#include <stage2_params.h>
#include <x86/mptable.h>

#if defined(WOLFBOOT_LINUX_PAYLOAD)
#include <x86/linux_loader.h>
#endif /* defined(WOLFBOOT_LINUX_PAYLOAD) */

#if defined(WOLFBOOT_TPM)
#include <tpm.h>
#endif /* WOLFBOOT_TPM */

#if defined(WOLFBOOT_ELF)
#include <elf.h>
#include <multiboot.h>

/**
 * @brief Maximum size of Multiboot2 boot info data structure.
 */
#define MAX_MB2_BOOT_INFO_SIZE 0x2000
/**
 * @brief Multiboot2 boot info data structure.
 */
uint8_t mb2_boot_info[MAX_MB2_BOOT_INFO_SIZE];
#endif
#ifdef WOLFBOOT_64BIT
#include <x86/paging.h>
#endif /* WOLFBOOT_64BIT */

#ifdef TARGET_kontron_vx3060_s2
static char *cmdline = "apic=verbose acpi=no pci=debug console=ttyS0,115200 debug";
#elif TARGET_x86_fsp_qemu
static char *cmdline = "console=ttyS0,115200 pci=earlydump debug";
#else
static char *cmdline = "auto";
#endif /* TARGET_kontron_vx3060_s2 */

/**
 * @brief Jump to the specified entry point.
 *
 * This function performs an unconditional jump to the provided entry point.
 *
 * @param entry The entry point address to jump to.
 */
void jump(uintptr_t entry)
{
    __asm__(
            "jmp *%0\r\n"
            :
            : "g"(entry));
}

/**
 * @brief Perform the boot process for the given application.
 *
 * This function performs the boot process for the specified application.
 * It either loads and boots a Linux payload or an ELF binary, depending on the
 * configuration.
 *
 * @param app Pointer to the start of the application.
 */
void do_boot(const uint32_t *app)
{
    struct stage2_parameter *stage2_params;

#ifdef WOLFBOOT_TPM
    wolfBoot_tpm2_deinit();
#endif /* WOLFBOOT_TPM */

    stage2_params = stage2_get_parameters();
#if defined(WOLFBOOT_LINUX_PAYLOAD)
    mptable_setup();
    load_linux((uint8_t *)app, stage2_params, cmdline);
#elif defined(WOLFBOOT_ELF)
    int r;
    uint64_t e;
    uint8_t *mb2_header;
    elf_mmu_map_cb mmu_cb = NULL;

#ifdef WOLFBOOT_64BIT
    mmu_cb = x86_paging_map_memory;
#endif /* WOLFBOOT_64BIT */

    /* TODO: to remove */
    mptable_setup();
    x86_paging_dump_info();
    /* Use available low memory as upper bound for ELF image size */
    if (stage2_params->tolum <= (uint32_t)(uintptr_t)app) {
        wolfBoot_printf("ELF: app address beyond TOLUM\r\n");
        panic();
    }
    r = elf_load_image_mmu((uint8_t *)app,
            stage2_params->tolum - (uint32_t)(uintptr_t)app, &e, mmu_cb);
    wolfBoot_printf("Elf loaded (ret %d), entry 0x%x_%x\r\n", r,
                    (uint32_t)(e >> 32),
                    (uint32_t)(e));
    x86_paging_dump_info();
    if (r != 0)
        panic();

#ifdef WOLFBOOT_MULTIBOOT2
    mb2_header = mb2_find_header((uint8_t*)app, 1024*1024*15);
    if (mb2_header == NULL) {
        wolfBoot_printf("No mb2 header found\r\n");
        panic();
    }
    wolfBoot_printf("mb2 header found at %x\r\n",
                    (uint32_t)(uintptr_t)mb2_header);
    r = mb2_build_boot_info_header(mb2_boot_info, mb2_header,
                                   stage2_params,
                                   MAX_MB2_BOOT_INFO_SIZE);
    if (r != 0) {
        wolfBoot_printf("can't build multiboot2 header, panicking\r\n");
        panic();
    }
    wolfBoot_printf("booting...\r\n");
    mb2_jump(e, (uint32_t)(uintptr_t)mb2_boot_info);
#else
    jump(e);
#endif /* WOLFBOOT_MULTIBOOT2 */

#else
#error "No payload compiled in"
#endif /* WOLFBOOT_LINUX_PAYLOAD */
}
#endif /* BOOT_X86_FSP_PAYLOAD_H_ */