mirror of
https://github.com/torvalds/linux.git
synced 2024-11-28 23:21:31 +00:00
38eb496d85
1, Describe the information passed from BootLoader to kernel. 2, Describe the meaning and values of the kernel image header field. Suggested-by: Xiaotian Wu <wuxiaotian@loongson.cn> Signed-off-by: Yanteng Si <siyanteng@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
43 lines
1.5 KiB
ReStructuredText
43 lines
1.5 KiB
ReStructuredText
.. 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 */
|