Re: kernel args from u-boot on M5282LITE

Hi Allon,

Allon Stern wrote:
> On Feb 11, 2008, at 2:20 AM, Greg Ungerer wrote:
>> Allon Stern wrote:
>>> So, I figured out a way to pass kernel arguments from u-boot on the 
>>> M5282LITE. U-Boot calls the kernel, passing arguments on the stack; 
>>> all that is needed is to stash the pointer to the arguments (stashed 
>>> in high mem) when the kernel first starts, and before the stack 
>>> pointer is trounced, then use that pointer slightly later when the 
>>> arguments are looked at.
>>> Any comments on this hack? Should I expect it to fail, and be 
>>> surprised that it works?
>>
>> The thing to watch is where in practice do the args end
>> up being in the memory map?
>>
>> The linux kernel will do a fair bit of setup (clear bss, initial
>> allocations, etc) before it gets around to looking at the args.
>> Will they have been overwritten by this time?
> 
> Well no. That's why I stash the pointer right after the disabling of 
> interrupts; I think it's the 3rd assembly instruction into the kernel...

Its not the pointer I am worried about :-)
It is what it points to. Where is the actual string of
the command line in memory. Will it be overwritten?

Regards
Greg




> I had a patch for the 2.6.19-uc1 kernel; Now that I'm on 2.6.24-uc0, 
> I'll apply it there and send out patches. The code has been cleaned up a 
> bit between releases. (okay patches - still waiting for a release ;) ;);) )
> -
> allon
> 
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