summaryrefslogtreecommitdiff
path: root/Documentation/loongarch/booting.rst
diff options
context:
space:
mode:
Diffstat (limited to 'Documentation/loongarch/booting.rst')
-rw-r--r--Documentation/loongarch/booting.rst42
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 */