Re: [PATCH 1/2] OLPC: Add support for calling into Open Firmware
From: H. Peter Anvin
Date: Mon Apr 21 2008 - 09:33:53 EST
Okay, stepping back a few steps, it's pretty clear that most of my
objections aren't really an issue for Geode/OLPC; however, I *really*
don't want others to pick it up as being "the" Open Firmware interface.
Within those constraints it makes sense to set up the PDEs in
swapper_pg_dir and let them propagate using the normal mechanisms.
** This is assuming that your OF interface does not rely on a 1:1
mapping of low memory being present at the time it makes a call. If it
*does*, then a separate page directory needs to be maintained for the OF
class. **
Thus, I'm willing to accept this with these changes:
- Please name things specific to the interface (as opposed to Open
Firmware in general, like the device tree) olpc_ofw or olpcfw, to denote
that this is an OLPC-specific interface. Thus,
CONFIG_OLPC_OPEN_FIRMWARE or something along those lines.
- Make it explicit in Kconfig that OLPC_OPEN_FIRMWARE conflicts with
X86_PAE, 64BIT, or X86_PAT.
- Change VMALLOC_END in include/asm-x86/pgtable_32.h so the kernel will
know to avoid this virtual memory range.
- Add a memory region to arch/x86/mm/dump_tabletables.c.
-hpa
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