On Apr 1, 2008, at 5:50 AM, Paul Mackerras wrote:
Kumar Gala writes:
For the sub-arches that support relocatable interrupt vectors (book-
e) its
reasonable to have memory start at a non-zero physical address.
For those
cases use the variable memstart_addr instead of the #define
PPC_MEMSTART
since the only uses of PPC_MEMSTART are for initialization and in the
future we can set memstart_addr at runtime to have a relocatable
kernel.
In those cases, is it still true that the kernel sits at the start of
the usable memory, or might there be usable memory before _stext?
In other words, is PAGE_OFFSET == KERNELBASE still true or not?
Both cases are possible.
Here are the four cases I see:
* Normal kernel (kernel at physical 0)
* kexec kernel (kernel at physical 32M, but still has access to memory
from physical 0 to 32M)
* cAMP kernel (kernel at non-zero offset) [eg. 256M offset]
* kexec cAMP kernel (kernel at 256M+32M, but has access to 256M + size)
- k
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