Re: [PAE support] Types + cosmetic fixes

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

On Mon, Feb 22, 2010 at 10:25:35AM +0100, Jean-Yves Migeon wrote:
> 
> Hi lists,
> 
> Before asking for review of the patch regarding PAE support inside native
> i386 kernel (inspired from jmorse@ work from a few weeks ago), I would like
> to commit these beforehand ([1] & [2]). I made them separate because they
> are not for PAE support "per-see."
> 
> They are mostly types + cosmetic fixes. As some of you may now, introducing
> PAE affects the x86 paradigm inside NetBSD a bit:
> - sizeof paddr_t != sizeof vaddr_t (64 bits for paddr_t, 32 bits for
> vaddr_t)

We already gave platorms like that (or had - the sh5 port). we already
have it for Xen ... So no major problems with this I guess.


> - "unsigned long" cannot be considered as a physical address anymore

It should not in the first place :)

> 
> This affect a couple of printfs(), printk() and debugging messages, as well
> as some variables types used inside x86 pmap [1].
> 
> Second small patch [2] contains fixes regarding UVM:
> - RLIMIT_RSS which is now set to VM_MAXUSER_ADDRESS (shouldn't it be set to
> MIN(VM_MAXUSER_ADDRESS, ptoa(uvmexp.free) instead?),

I think it should be MIN(VM_MAXUSER_ADDRESS, ptoa(uvmexp.free).
Otherwise it's a change in behavior not related to i386PAE.

> - ptoa => ctob use (to avoid vaddr_t casts, which might be bad for systems
> with total RAM > 4GB)
> - a small fix inside AGP heuristics to avoid masking high order bits
> 
> Compile tested for ALL, GENERIC, XEN3 kernels for i386, and GENERIC, XEN3*
> for amd64.

Looks good.

> 
> In case someone wonders, if PAE is added as default option for ALL, more
> fixes will be needed in some drivers under sys/dev/ (paddr_t vs unsigned
> long issues). Question is: should it be added to ALL for additional checks?

I think so. Such issues should be fixed in MI code anyway. paddr_t !=
unsigned long is something we want to support.

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
--