1 .. SPDX-License-Identifier: GPL-2.0 2 3 ======================= 4 Booting Linux/LoongArch 5 ======================= 6 7 :Author: Yanteng Si <siyanteng@loongson.cn> 8 :Date: 18 Nov 2022 9 10 Information passed from BootLoader to kernel 11 ============================================ 12 13 LoongArch supports ACPI and FDT. The information that needs to be passed 14 to the kernel includes the memmap, the initrd, the command line, optionally 15 the ACPI/FDT tables, and so on. 16 17 The 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 27 Header of Linux/LoongArch kernel images 28 ======================================= 29 30 Linux/LoongArch kernel images are EFI images. Being PE files, they have 31 a 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 */
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