the issue is that that 1/2/3G of kernel space is in a total of 4G of address space, and given the size of the kernel and the alignment requirements, things are a bit limited
on amd64 you have much more address space to work with, so that 2G of kernel space can be moved to far more locations
Posted May 28, 2011 22:13 UTC (Sat) by PaXTeam (subscriber, #24616)
[Link]
> the issue is that that 1/2/3G of kernel space is in a total of 4G of
> address space, and given the size of the kernel and the alignment
> requirements, things are a bit limited
the exact same limits apply to amd64 kernels as well.
> on amd64 you have much more address space to work with, so that 2G of
> kernel space can be moved to far more locations
you're wrong, the kernel image cannot be at arbitrary addresses, it *must* be in the top 2GB of the 64 bit virtual address space. i suggest you study the amd64 ABI and in particular -mcmodel=kernel.