Physical memory allocation to L4linux

Adam Lackorzynski adam at
Mon Sep 15 23:53:16 CEST 2014


On Mon Sep 15, 2014 at 18:25:37 +0000, Masti  Ramya Jayaram wrote:
> Thanks for the input. I will try changing one of the suggested functions. 
> It would be great out of curiosity if you could elucidate why the following occurs.  
> I see that there is a new iomem region being created and this happens
> only when I try to read from the mapped region - not until then. But
> none of this reaches the kernel or maybe I am not sure where to look..

Well, it should reach the kernel. For sigma0 mappings appear out of
nothing (it's the root), so you should at least see it in the mapping
loop in map_util.cpp's map() function (also see the comments on sigma0
> In fact, I see that the init_mem file parses the kernel  memory
> descriptors to find the regions. So under what circumstances does
> sigma0 go back to the kernel for mem/io? 

In this case there a fpage is created that is used in the reply to the
client which will then create the mapping.

Adam                 adam at

More information about the l4-hackers mailing list