2.1.Information passed from BootLoader to kernel¶

LoongArch supports ACPI and FDT. The information that needs to be passedto the kernel includes the memmap, the initrd, the command line, optionallythe ACPI/FDT tables, and so on.

The kernel is passed the following arguments onkernel_entry :

• a0 = efi_boot:efi_boot is a flag indicating whetherthis 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.

2.2.Header of Linux/LoongArch kernel images¶

Linux/LoongArch kernel images are EFI images. Being PE files, they havea 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 */