Hi Thanks for your reply On Tue, Aug 11, 2009 at 10:38 AM, Mulyadi Santosa <[email protected] > wrote:
> Hello > > On Mon, Aug 10, 2009 at 11:07 PM, Basavaraj > Dengi<[email protected]> wrote: > > I am porting 'kdb' to omap3430 platform. > > for command 'mdp arg' [mdp is memory dump physical and arg is any > physical > > address] this code gets executed. I dint test for every address b/w > > 0-0xc0000000 > > but lots of them randomnly. The other 'md' commands do work for kernel > high > > memory address.[ie. > 0xc0000000] But mdp fails for all the addresses. > > > > this piece of code is part of architecture independant patch of kdb; [for > > 2.6.24 kernel] > > kdb community is very inactive and moreover this question is related to > > memory management part of the kernel, so I thought i will ask it here > > I have no experience about embedded development at all, including > Omap. But questions that cross my mind are: > 1. Is Omap MMU or MMU less? If it is MMU-less, I think talking about > page frame is completely irrelevant here. Or at least MMU related > functions will try to "emulate" the MMU situation, but still not the > same as MMU based arch > OMAP is having MMU > > 2. Still related with above question, perhaps this Omap arch implement > kinda "memory hole"? So not every memory address range is mapped? > I am not sure about this; > > 3. Does Omap use memory split like x86 does? I mean 3:1 for user > space:kernel space? > Ya it has memory split. > > The possibility that some "md" commands doesn't work when dealing with > address below kernel space range is it has to grab the page directory > of current running process and does the translation based on this PGD > (again, assuming Omap is using MMU). And this grabbing mechanism is > either unimplemented yet or has some bugs. > I agree; But the issue here is not about md commands failing for lower memory addresses; Issue is that mdp fails for higher memory [>3GB] addresses. I am trying to figure out the same. > > My thoughts might have flaws, so feel free to debate them. > > -- > regards, > > Mulyadi Santosa > Freelance Linux trainer > blog: the-hydra.blogspot.com >
