EFI Prekernel (6/N): Kernel: Preparations for booting with the EFIPrekernel #25668
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`load_kernel_symbols_from_data` modifies the contents of this segment, so it needs to be writable.
Setting the boot method to Multiboot1 is no longer necessary because we don't use a hard-coded multiboot memory map anymore.
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The bootup speed depends on the firmware. Booting with EDK2 will definitely be slower, but booting using U-Boot as the "UEFI firmware" should be just as fast. UEFI support will give us a framebuffer for free, if the firmware supports the UEFI Graphics Output Protocol (GOP). We currently use the linux boot protocol for aarch64 and riscv64, which I think isn't very clean tbh (but I think we should keep the current pre_init code even with the EFIPrekernel completely functional). UEFI is (sadly) the only widespread OS-agnostic boot protocol that works on all our supported architectures. |
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Oh no, not this panic
But I don't see how that could be caused by this PR? |
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Oh duh - MUST(StaticParsing::find_rsdp_in_platform_specific_memory_locations());
+ rsdp = MUST(StaticParsing::find_rsdp_in_platform_specific_memory_locations()); |
The EFIPrekernel will identity map one page to set up virtual memory, instead of identity mapping its entire memory like the current multiboot prekernel.
This also required making the aarch64 pre_init code pass the boot_info to init.
This will be necessary when booting with the EFIPrekernel. x86-64 also loads the IDT in Processor::initialize.
The EFIPrekernel will set `acpi_rsdp_paddr` to the RSDP address found in the configuration table.
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This PR includes all kernel changes necessary for making the kernel bootable with the EFIPrekernel.