projects / linux-block.git / blame
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|---|---|---|
| 38eb496d YS |
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 */ |