| .. 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 */ |
