bootconf Binary

The mkimage command builds a binary file called bootconf. The bootconf file contains a data structure called BootConf, which describes the system image contents and layout. mkimage includes the bootconf binary file in one of the system image memory banks.

The initial loader boots the ChorusOS operating system, jumping to the entry point of bootconf binary.

bootconf is a board-independent program that gets control from the board-specific initial loader and transfers control to the board-specific bootstrap program. In some cases, the initial loader needs to pass a board-dependent parameter to the bootstrap. This parameter can be loaded into a specific CPU register, and bootconf passes the entry value of the register to the bootstrap program as an opaque parameter. The register is:

• eax on an ix86 systemix86 system

• r3 on a PowerPC system

• oO on a SPARC^TM v8 system

When the bootconf binary is entered, it sets up a program stack in a stack area within its data segment, finds the descriptor of the bootstrap binary in the BootConf structure, and jumps to this entry point, passing the following parameters:

• The address of the BootConf structure

• An opaque value from the initial loader

To jump to the bootstrap entry point, bootconf uses the standard C function invocation conventions. The bootstrap entry point is:

typedef void (*BootEntry) (struct BootConf*, void* cookie);