1.. SPDX-License-Identifier: GPL-2.0 2 3======================= 4Booting Linux/LoongArch 5======================= 6 7:Author: Yanteng Si <siyanteng@loongson.cn> 8:Date: 18 Nov 2022 9 10Information passed from BootLoader to kernel 11============================================ 12 13LoongArch supports ACPI and FDT. The information that needs to be passed 14to the kernel includes the memmap, the initrd, the command line, optionally 15the ACPI/FDT tables, and so on. 16 17The kernel is passed the following arguments on `kernel_entry` : 18 19 - a0 = efi_boot: `efi_boot` is a flag indicating whether 20 this boot environment is fully UEFI-compliant. 21 22 - a1 = cmdline: `cmdline` is a pointer to the kernel command line. 23 24 - a2 = systemtable: `systemtable` points to the EFI system table. 25 All pointers involved at this stage are in physical addresses. 26 27Header of Linux/LoongArch kernel images 28======================================= 29 30Linux/LoongArch kernel images are EFI images. Being PE files, they have 31a 64-byte header structured like:: 32 33 u32 MZ_MAGIC /* "MZ", MS-DOS header */ 34 u32 res0 = 0 /* Reserved */ 35 u64 kernel_entry /* Kernel entry point */ 36 u64 _end - _text /* Kernel image effective size */ 37 u64 load_offset /* Kernel image load offset from start of RAM */ 38 u64 res1 = 0 /* Reserved */ 39 u64 res2 = 0 /* Reserved */ 40 u64 res3 = 0 /* Reserved */ 41 u32 LINUX_PE_MAGIC /* Magic number */ 42 u32 pe_header - _head /* Offset to the PE header */ 43