ARMv8 - 32bit app support on 64bit Linux Kernel and Virtual Address Space mapping

Before going to that first have a look at my post regarding ARMv8 - 64 bit  Linux Virtual Address Space.

To support 32 bit app on 64 bit kernel ,  CONFIG_COMPAT feature needs to be enabled.

 Enable CONFIG_COMPAT  : 

This option enables support for a 32-bit EL0 running under a 64-bit kernel at EL1.   AArch32-specific components such as system calls, the user helper functions, VFP support and the ptrace interface are handled appropriately by the kernel.

 If you want to execute 32-bit userspace applications, say Y.

32 bit app on  64bit kernel can use 4GB of user space and 512GB of kernel space. 

At present kernel with 32bit app we can use 4K page support.  

Still there is a way to support 32bit app with 64k page support. I will update soon on the same.