Kernel Address Space

A board-specific configuration can specify the initial kernel address space layout. If specified, the object that defines it must be named ksp and is usually contained in the folder named KSP. The exact semantics and requirements for the initial kernel address space specifications are family dependent.

An MPC60x family-dependent configuration must specify the initial kernel address space layout.

The SBC8260 board-dependent configuration specifies the initial kernel address space as follows:

Example 5-5 SBC8260 board-dependent configursation

  <folder name='Kernel address SPace'>
    <description>kernel address space configurations</description>

    <definition name='ksp'>
      <description>flat memory management:           system address space layout
virtual memory management:      see PPC 60x BKI</description>

      <type name='AddrSpaceMap' />
<!--
        PowerPC 60x bus SDRAM: 0x00000000 .. 0x00ffffff
-->
      <value index='size'>
        <value field='vaddr'><const>0x00000000</const></value>
        <value field='valid'><true/></value>
        <value field='paddr'><const>0x00000000</const></value>
        <value field='attr'>
          <const>KSP_PPC60x_BAT|KSP_PPC60x_M|KSP_PPC60x_RW</const>
        </value>
      </value>
<!--
        Local bus 32-bit SDRAM: 0x02000000 .. 0x02ffffff
-->
      <value index='size'>
        <value field='vaddr'><const>0x01000000</const></value>
        <value field='valid'><false/></value>
      </value>
<!--
        8260 internal memory map (IMMR): 0x0f000000 .. 0x0f01ffff
-->
      <value index='size'>
        <value field='vaddr'><const>0x0f000000</const></value>
        <value field='valid'><true/></value>
        <value field='paddr'><const>0x0f000000</const></value>
        <value field='attr'>
          <const>KSP_PPC60x_BAT|KSP_PPC60x_G|KSP_PPC60x_I|KSP_PPC60x_RW</const>
        </value>
      </value>

      <value index='size'>
        <value field='vaddr'><const>0x0f020000</const></value>
        <value field='valid'><false/></value>
      </value>
<!--
        8-bits general purpose FLASH memory: 0xe0000000 .. 0xe0ffffff
-->
<!--
        32-bits general purpose FLASH memory.
                expandable : 0xfc000000 .. 0xfcffffff
                boot       : 0xfe000000 .. 0xffffffff
-->
      <value index='size'>
        <value field='vaddr'><const>0xfc000000</const></value>
        <value field='valid'><true/></value>
        <value field='paddr'><const>0xfc000000</const></value>
        <value field='attr'>
          <const>KSP_PPC60x_BAT|KSP_PPC60x_RO</const></value>
      </value>
    </definition>

  </folder>

According to this definition, the microkernel will initially map the RAM space from physical address 0 to 0x01000000, to the virtual address 0, using one pair of BATs. It will also map the flash memory space from physical address 0xfc000000 to 0xffffffff, to the virtual address 0xfc000000 using another pair of BATs. Finally, the microkernel will map 0x00020000 bytes of 8260 Internal Memory Mapped Registers based at the physical address 0x0f000000 to the virtual address 0x0f000000. The rest of the virtual address space will be invalid.