[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: wortel problems
From: |
Marcus Brinkmann |
Subject: |
Re: wortel problems |
Date: |
Wed, 1 Oct 2003 08:56:53 +0200 |
User-agent: |
Mutt/1.5.4i |
On Wed, Oct 01, 2003 at 04:10:37AM +0200, Johan Rydberg wrote:
> /* Allocate a single page at address 0, because we don't want to
> bother anybody with that silly page. */
> sigma0_get_fpage (l4_fpage (0, l4_min_page_size ()));
>
> I'm not really sure why this is done, but it's not valid for PowerPC
> (region 0-0x3000 is used for exception vectors, and sigma0 treats it
> as reserved.) Why does it allocate and throw away page zero? I've
> just commented out this piece of code for the moment.
physmem uses 0 as the return value for a failed zalloc, so it can not be
used in physmem anyway. Apart from that, mapping it into physmem at address
0 would prevent any exception from being created when dereferencing a null
pointer. The best thing to do is to allocate the page at 0 and remap it
into physmem at a higher address (ie, add it to the end of available
memory), so it becomes usable.
Is this causing a panic on ppc, or does it just not work? We can ignore
any failure (return value l4_nilpag0e) here.
> I don't know if something is failing in the communication between
> wortel and sigma0, but requesting a block of memory with the size
> if (1 << 31) makes the kernel break into the kernel debugger with
> the following message:
>
> map_fpage(from=c0043000, to=c004a000, base=0, sndfp=800001f7, rcvfp=10)
> --- KD# map_fpage(): Mapping already exists. ---
sigma0 patch is supposed to fix that, if it doesn't I don't know why.
Thanks,
Marcus
--
`Rhubarb is no Egyptian god.' GNU http://www.gnu.org address@hidden
Marcus Brinkmann The Hurd http://www.gnu.org/software/hurd/
address@hidden
http://www.marcus-brinkmann.de/
- Re: wortel problems,
Marcus Brinkmann <=
- Re: wortel problems, Espen Skoglund, 2003/10/01
- Re: wortel problems, Johan Rydberg, 2003/10/01
- Re: wortel problems, Johan Rydberg, 2003/10/01
- Re: wortel problems, Espen Skoglund, 2003/10/01
- Re: wortel problems, Johan Rydberg, 2003/10/01
- Re: wortel problems, Espen Skoglund, 2003/10/01
- Re: wortel problems, Espen Skoglund, 2003/10/01
- Re: wortel problems, Johan Rydberg, 2003/10/01