ARC: Proper kernel mapping

[VVIsaev]

Use proper page flags for different memory sections, for example X is used only for text section.

Previously we mapped kernel as an one big chunk.

Now kernel mapping is page-based, so it requires to have memblock initialized to be able to allocate page entries dynamically.

Signed-off-by: Vladimir Isaev [email protected]

[xxkent]

I built this kernel with 4Kb page for kernel and user space size for HS58 and ran some tests. Here are the tests that completed successfully:

1. tinymembench
2. hackbench

Here are the tests that completed with errors:

1. lmbench(result is Jtag stall)

Further investigation is required related to lmbench. The reason of this fail(SW/HW) is not clear now.

[xxkent]

Closing since these changes have already merged from a different branch.