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.. SPDX-License-Identifier: GPL-2.0 ======================= Booting Linux/LoongArch ======================= :Author: Yanteng Si <siyanteng@loongson.cn> :Date: 18 Nov 2022 Information passed from BootLoader to kernel ============================================ LoongArch supports ACPI and FDT. The information that needs to be passed to the kernel includes the memmap, the initrd, the command line, optionally the ACPI/FDT tables, and so on. The kernel is passed the following arguments on `kernel_entry` : - a0 = efi_boot: `efi_boot` is a flag indicating whether this boot environment is fully UEFI-compliant. - a1 = cmdline: `cmdline` is a pointer to the kernel command line. - a2 = systemtable: `systemtable` points to the EFI system table. All pointers involved at this stage are in physical addresses. Header of Linux/LoongArch kernel images ======================================= Linux/LoongArch kernel images are EFI images. Being PE files, they have a 64-byte header structured like:: u32 MZ_MAGIC /* "MZ", MS-DOS header */ u32 res0 = 0 /* Reserved */ u64 kernel_entry /* Kernel entry point */ u64 _end - _text /* Kernel image effective size */ u64 load_offset /* Kernel image load offset from start of RAM */ u64 res1 = 0 /* Reserved */ u64 res2 = 0 /* Reserved */ u64 res3 = 0 /* Reserved */ u32 LINUX_PE_MAGIC /* Magic number */ u32 pe_header - _head /* Offset to the PE header */ |