ARM : Kernel : Setting up of MMU in head.S

[sk.syed2]

> The 2 lines above
> 1:  orr    r3, r7, r5, lsl #20        @ flags + kernel base ==> Correct
>     str    r3, [r4, r5, lsl #2]        @ identity mapping  ==> ??
>
> create a section entry using index based on physical address.
Lets say before mmu is turned on PC is at physical address XXX, also
say at XXX there is going to be mmu on instruction. The next
instruction fetch would be from XXX + 4 which would now be VIRTUAL
address(as mmu is turned on), which should still get converted to (via
page tables set up as above) to XXX + 4 (in physical). This is called
identity mapping as specified in the comments. Hope this helps.

-syed