On 12/13/2012 04:44 PM, Yinghai Lu wrote:
On Thu, Dec 13, 2012 at 4:38 PM, H. Peter Anvin <[email protected]> wrote:
On 12/13/2012 04:13 PM, Yinghai Lu wrote:
It is definitely the minmum we can rely on, and so is the minimum we should
rely on. In fact, we don't even need .bss/.brk to be mapped, but we
probably should require that as a matter of protocol.
in my version of arch/x86/kernel/head_64.S is using BRK to do
ident/kernel high mapping
for kernel that is above 4G.
so .brk is needed.
Yes, with the page fault approach we wouldn't need to do that, so that
version is the minimum that can, practically, be required (one can
constrain that even further, down to only needing a handful of pages,
but that gets progressively more painful for little to no gain.)
However, as I said, rather than tying our hands for the future we should
include .bss/.brk in the requirement.
-hpa
--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.
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