GIET_VM / Boot-Loader

The GIET-VM boot-loader is defined in the boot.c​ file.

The boot_init() function makes the initialisation in two steps:

Sequencial step

The first step executed by proc[0][0][0], while other processors are in wait state.

void boot_pmem_init()

This function makes the physical memory allocators initialisation. The GIET VM uses two types of pages:

• BPP : Big Physical Page (2 Mbytes).
• SPP : Small Physical Page (4 Kbytes).

There is one SPP and one BPP allocator per cluster containing a physical memory bank. All the physical memory allocation is done by the boot-loader

void boot_ptabs_init()

This function makes the page table initialisation. There is one page table per user application (vspace) defined in the mapping. All these

• Proc[0][0][0] MMU activation
• Private vobjs initialisation : boot_vobjs_init()
• Schedulers initialisation : boot_schedulers init()
• Peripherals initialisation : boot_peripherals_init()
• Kernel & application code loading : boot_elf_load()
• Start all other processors

Parallel step

The second step is executed in parallel by all processors:

• CP0_SCHED register initialisation
• MMU Activation
• Status Register Initialisation (to use the GIET_VM exception handler).
• Jump to kernel_init()