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Split Linux header into header and source file for implementation
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| /* | ||
| * Copyright 2023, UNSW | ||
| * | ||
| * SPDX-License-Identifier: BSD-2-Clause | ||
| */ | ||
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| #include "../../util/util.h" | ||
| #include "linux.h" | ||
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| /* | ||
| * The structure of the kernel image header and the magic value comes from the | ||
| * Linux kernel documentation that can be found in the Linux source code. The | ||
| * path is Documentation/arm64/booting.rst or Documentation/arch/arm64/booting.rst | ||
| * depending on the version of the source code. | ||
| */ | ||
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| #define LINUX_IMAGE_MAGIC 0x644d5241 | ||
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| struct linux_image_header { | ||
| uint32_t code0; // Executable code | ||
| uint32_t code1; // Executable code | ||
| uint64_t text_offset; // Image load offset, little endian | ||
| uint64_t image_size; // Effective Image size, little endian | ||
| uint64_t flags; // kernel flags, little endian | ||
| uint64_t res2; // reserved | ||
| uint64_t res3; // reserved | ||
| uint64_t res4; // reserved | ||
| uint32_t magic; // Magic number, little endian, "ARM\x64" | ||
| uint32_t res5; // reserved (used for PE COFF offset) | ||
| }; | ||
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| // bool linux_start(size_t boot_vcpu_id, uintptr_t kernel_pc, uintptr_t dtb, uintptr_t initrd) { | ||
| // seL4_UserContext regs = {0}; | ||
| // regs.x0 = GUEST_DTB_VADDR; | ||
| // regs.spsr = 5; // PMODE_EL1h | ||
| // regs.pc = kernel_pc; | ||
| // // Set all the TCB registers | ||
| // seL4_Word err = seL4_TCB_WriteRegisters( | ||
| // BASE_VM_TCB_CAP + boot_vcpu_id, | ||
| // false, // We'll explcitly start the guest below rather than in this call | ||
| // 0, // No flags | ||
| // SEL4_USER_CONTEXT_SIZE, // Writing to x0, pc, and spsr // @ivanv: for some reason having the number of registers here does not work... (in this case 2) | ||
| // ®s | ||
| // ); | ||
| // assert(err == seL4_NoError); | ||
| // if (err != seL4_NoError) { | ||
| // LOG_VMM_ERR("Failed to write registers to boot vCPU's TCB (id is 0x%lx), error is: 0x%lx\n", boot_vcpu_id, err); | ||
| // return false; | ||
| // } | ||
| // // Set the PC to the kernel image's entry point and start the thread. | ||
| // LOG_VMM("starting guest at 0x%lx, DTB at 0x%lx, initial RAM disk at 0x%lx\n", | ||
| // regs.pc, regs.x0, initrd); | ||
| // sel4cp_vm_restart(boot_vcpu_id, regs.pc); | ||
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| // return true; | ||
| // } | ||
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| uintptr_t linux_setup_images(uintptr_t ram_start, | ||
| uintptr_t kernel, | ||
| size_t kernel_size, | ||
| uintptr_t dtb_src, | ||
| uintptr_t dtb_dest, | ||
| size_t dtb_size, | ||
| uintptr_t initrd_src, | ||
| uintptr_t initrd_dest, | ||
| size_t initrd_size) | ||
| { | ||
| // First we inspect the kernel image header to confirm it is a valid image | ||
| // and to determine where in memory to place the image. | ||
| struct linux_image_header *image_header = (struct linux_image_header *) kernel; | ||
| assert(image_header->magic == LINUX_IMAGE_MAGIC); | ||
| if (image_header->magic != LINUX_IMAGE_MAGIC) { | ||
| LOG_VMM_ERR("Linux kernel image magic check failed\n"); | ||
| return 0; | ||
| } | ||
| // Copy the guest kernel image into the right location | ||
| uintptr_t kernel_dest = ram_start + image_header->text_offset; | ||
| // This check is because the Linux kernel image requires to be placed at text_offset of | ||
| // a 2MB aligned base address anywhere in usable system RAM and called there. | ||
| // In this case, we place the image at the text_offset of the start of the guest's RAM, | ||
| // so we need to make sure that the start of guest RAM is 2MiB aligned. | ||
| assert((ram_start & ((1 << 20) - 1)) == 0); | ||
| LOG_VMM("Copying guest kernel image to 0x%x (0x%x bytes)\n", kernel_dest, kernel_size); | ||
| memcpy((char *)kernel_dest, (char *)kernel, kernel_size); | ||
| // Copy the guest device tree blob into the right location | ||
| // Linux does not allow the DTB to be greater than 2 megabytes in size. | ||
| assert(dtb_size <= (1 << 21)); | ||
| if (dtb_size > (1 << 21)) { | ||
| LOG_VMM_ERR("Linux expects size of DTB to be less than 2MB, DTB size is 0x%lx bytes\n", dtb_size); | ||
| return 0; | ||
| } | ||
| // Linux expects the address of the DTB to be on an 8-byte boundary. | ||
| assert(dtb_dest % 0x8 == 0); | ||
| if (dtb_dest % 0x8) { | ||
| LOG_VMM_ERR("Linux expects DTB address to be on an 8-byte boundary, DTB address is 0x%lx\n", dtb_dest); | ||
| return 0; | ||
| } | ||
| LOG_VMM("Copying guest DTB to 0x%x (0x%x bytes)\n", dtb_dest, dtb_size); | ||
| memcpy((char *)dtb_dest, (char *)dtb_src, dtb_size); | ||
| // Copy the initial RAM disk into the right location | ||
| // @ivanv: add checks for initrd according to Linux docs | ||
| LOG_VMM("Copying guest initial RAM disk to 0x%x (0x%x bytes)\n", initrd_dest, initrd_size); | ||
| memcpy((char *)initrd_dest, (char *)initrd_src, initrd_size); | ||
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| return kernel_dest; | ||
| } |
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