Skip site navigation (1)Skip section navigation (2)
Date:      Thu, 3 Apr 2003 19:26:20 -0500 (EST)
From:      Daniel Eischen <eischen@pcnet1.pcnet.com>
To:        Peter Wemm <peter@wemm.org>
Cc:        freebsd-threads@freebsd.org
Subject:   Re: 1:N threading 
Message-ID:  <Pine.GSO.4.10.10304031923290.4135-100000@pcnet1.pcnet.com>
In-Reply-To: <20030403233541.F02592A8A7@canning.wemm.org>

next in thread | previous in thread | raw e-mail | index | archive | help
On Thu, 3 Apr 2003, Peter Wemm wrote:

> Daniel Eischen wrote:
> 
> > The patches are available:
> > 
> >   http://people.freebsd.org/~deischen/libpthread.diffs
> > 
> > FYI, since this is a new mailing list, the above changes
> > are meant to give libpthread M:N capability.
> > 
> > I don't need testers; I have enough bugs that I know about
> > to fix.
> 
> +	__asm__("movl %%gs, %0" : "=r" (id));
> +	id >>= 3;
> +	if (id - NLDT < 0)
> 
> There is a problem here, NLDT is kernel private and changes depending on
> things like whether SMP is enabled or what the maximum number of cpus
> is.
> 
> You're trying to find if its a local or global selector, right?
> What you really want is bit 2 which tells you which it is.
> 
> #define ISLDT(s)        ((s)&SEL_LDT)   /* is it local or global */
> #define SEL_LDT 4               /* local descriptor table */

OK, but if NLDT is kernel private, how do can I know
what LDTs I can use as local?  (*)

(*) The only thing I know about LDTs came from an Intel
    486 architecture manual.

-- 
Dan Eischen



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?Pine.GSO.4.10.10304031923290.4135-100000>