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| author | Yanteng Si <siyanteng@loongson.cn> | 2022-12-08 09:59:15 +0300 |
|---|---|---|
| committer | Huacai Chen <chenhuacai@loongson.cn> | 2022-12-08 09:59:15 +0300 |
| commit | 38eb496d85b89d6ad8fe9701acd2ac1de804b6c1 (patch) | |
| tree | cfc84740cf0f1b1b2ba296a00ee8d409c3ad8972 /Documentation/loongarch/booting.rst | |
| parent | b681604edab66f20dde767f4690e554f26c5bfb9 (diff) | |
| download | linux-38eb496d85b89d6ad8fe9701acd2ac1de804b6c1.tar.xz | |
docs/LoongArch: Add booting description
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>
Diffstat (limited to 'Documentation/loongarch/booting.rst')
| -rw-r--r-- | Documentation/loongarch/booting.rst | 42 |
1 files changed, 42 insertions, 0 deletions
diff --git a/Documentation/loongarch/booting.rst b/Documentation/loongarch/booting.rst new file mode 100644 index 000000000000..91eccd410478 --- /dev/null +++ b/Documentation/loongarch/booting.rst @@ -0,0 +1,42 @@ +.. 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 */ |