:orphan:

.. title:: CONFIG_KERNEL_VM_OFFSET

.. kconfig:: CONFIG_KERNEL_VM_OFFSET

CONFIG_KERNEL_VM_OFFSET
#######################

*Kernel offset within address space*

Type: ``hex``

Help
====

.. code-block:: none

    Offset that the kernel image begins within its address space,
    if this is not the same offset from the beginning of RAM.

    Some care may need to be taken in selecting this value. In certain
    build-time cases, or when a physical address cannot be looked up
    in page tables, the equation:

        virt = phys + ((KERNEL_VM_BASE + KERNEL_VM_OFFSET) -
                       (SRAM_BASE_ADDRESS + SRAM_OFFSET))

    Will be used to convert between physical and virtual addresses for
    memory that is mapped at boot.

    This uncommon and is only necessary if the beginning of VM and
    physical memory have dissimilar alignment.

Direct dependencies
===================

\ :kconfig:`X86 <CONFIG_X86>` || \ :kconfig:`MMU <CONFIG_MMU>`

*(Includes any dependencies from ifs and menus.)*

Defaults
========

- 0x100000 if \ :kconfig:`MMU <CONFIG_MMU>`
- 0

Kconfig definitions
===================



At ``<Zephyr Architecture>/x86/Kconfig:190``

Included via ``Kconfig:8`` → ``Kconfig.zephyr:39`` → ``<Zephyr Architecture>/Kconfig:12``

Menu path: (Top) → X86 Architecture Options

.. code-block:: kconfig

    config KERNEL_VM_OFFSET
    	hex
    	default 0x100000 if MMU
    	depends on X86

----

At ``<Zephyr Architecture>/Kconfig:642``

Included via ``Kconfig:8`` → ``Kconfig.zephyr:39``

Menu path: (Top) → Enable MMU features

.. code-block:: kconfig

    config KERNEL_VM_OFFSET
    	hex "Kernel offset within address space"
    	default 0
    	depends on MMU
    	help
    	  Offset that the kernel image begins within its address space,
    	  if this is not the same offset from the beginning of RAM.
	  
    	  Some care may need to be taken in selecting this value. In certain
    	  build-time cases, or when a physical address cannot be looked up
    	  in page tables, the equation:
	  
    	      virt = phys + ((KERNEL_VM_BASE + KERNEL_VM_OFFSET) -
    	                     (SRAM_BASE_ADDRESS + SRAM_OFFSET))
	  
    	  Will be used to convert between physical and virtual addresses for
    	  memory that is mapped at boot.
	  
    	  This uncommon and is only necessary if the beginning of VM and
    	  physical memory have dissimilar alignment.

*(The 'depends on' condition includes propagated dependencies from ifs and menus.)*