Re: [PATCH]Fix broken VMI in 2.6.27-rc..

From: H. Peter Anvin
Date: Thu Aug 07 2008 - 19:54:41 EST


Jeremy Fitzhardinge wrote:
H. Peter Anvin wrote:
The fixmap area should never have been made movable. It's utter braindamage.

Shrug. It's been like that for a couple of years now. It was one of the very first paravirt-ops patches. It wasn't controversial then, and nobody seems to have noticed since.

The Linux kernel was never a paragon of perfection - it was never meant to be. Just because a bit of cruft went unnoticed into the kernel doesn't mean we shouldn't fix it.

Given the x86 architecture, it's inevitable that PV will want to reserve address space at the top of memory, and therefore the fixmap area needs to be moved out of that space.

OK. But there's a few places where the code uses FIXADDR_TOP to mean "top of kernel address space", so we'd need to come up with a proper symbol for that.

I suggest KERNEL_TOP.

-hpa

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