Re: CVS commit: src/sys/arch

["Christoph Egger" <Christoph_Egger%gmx.de@localhost>]

> Hi,
> 
> Why are any types other than in the pmap different between
> PAE and !PAE?
> 
> When this was originally proposed I asked for stuff like
> paddr_t to be 64 bits no matter what the kernel compile
> settings where.

Interesting to hear that from your side. When asked for this
a debate about overhead started.

Christoph

 
> Thanks.
> 
> 
> On Mon, Aug 16, 2010 at 10:45:10PM +0200, Jean-Yves Migeon wrote:
> > On 16.08.2010 22:22, matthew green wrote:
> > >> Module Name:     src
> > >> Committed By:    jym
> > >> Date:            Mon Aug 16 19:39:06 UTC 2010
> > >>
> > >> Modified Files:
> > >>  src/sys/arch/i386/i386: machdep.c
> > >>  src/sys/arch/x86/include: cpu.h
> > >>
> > >> Log Message:
> > >> Add machdep.pae sysctl(7) for i386. Thanks to Paul and Joerg for
> their
> > >> reviews.
> > >>
> > >> In kernel, it matches the 'i386_use_pae' variable (0: kernel does not
> use
> > >> PAE, 1: kernel uses PAE). Will be used by i386 kvm(3) to know the
> functions
> > >> that should get called for VA => PA translations.
> > > 
> > > does this work for core files as well?
> > >
> > > if not, wouldn't this feature be better done use ugly kvm/nlist so
> > > that it works with the same code on dead kernels?  getting a 0/1
> > > value via kvm shouldn't really be considered any real problem.
> > 
> > That's the purpose; I don't know of any other way. The sysctl is only
> > there for practical purposes: cpuctl(8) can indicate that the CPU
> > supports PAE, but there is no easy way to know if it is active or not
> > (unless playing with config -x together with the booted kernel, not very
> > practical...). Hence, the sysctl machdep.
> > 
> > > (why the extern in cpu.h?  i doesn't seem necessary.)
> > 
> > Yes; I wanted to place it at the same level as i386_use_fxsave.
> > i386_use_pae may get use elsewhere eventually, so I added it to cpu.h.
> > 
> > -- 
> > Jean-Yves Migeon
> > jeanyves.migeon%free.fr@localhost