Re: syscall adressing problem

Wolfgang Denk wrote:

In message [off-list ref] you wrote:

quoted

Further searching leaded to the following:
    Sometimes fopen or open syscall work well
    Whenever they dont work they are call from the libc.so and the
filename paramter adresses are 0x0fxxxxxx.

I've seen very similar problems,  but  on  MPC8xx  system  with  more
current  kernels.  The  reason  was a change in arch/ppc/lib/string.S
which completely f*cked up the caches (ok - the  MPC8xx  have  smalle
cache line sizes).

Thanks for the quick answer.

My cache line size is the standard 32 byte. As I found in older messages
from the mailing list, these string.S problems concern only unusual cache
line sizes.
Anyway I got the 2.2.6 and the 2.2.13 kernel sources and gave it a try
--> no success.
Then I tried to replace the copy_from_user in sys_open with my own
read_through (flushes cache first, then reads memory) function.  --> no
success.
Actually the strings to be passed to the syscall are readable from
everywhere in user space, but in kernel space it reads just trash at the
same adress.
There are (just my opinion) only two possibilities:
    an adress translation problem in the kernel for adresses < 0x10000000

   something is overwriting the memory space of the string - parameters
for sys_open

regards
    Rene

Try (1) disabling caches; and (2) arch/ppc/lib/string.S from an older
(2.2.13) kernel version.

It's just a guess, but maybe worth a try.

Wolfgang Denk

--
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd@denx.de
In an infinite universe all things are possible, including the possi-
bility that the universe does not exist.
                        - Terry Pratchett, _The Dark Side of the Sun_

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hello

I'm addressing you folks at ppc-embedded because frankly, I don't know how
to find any relevant info on this issue. We are developing a single-board
solution with a CT69000 display controller. I built the XFree 4.0.1 on a
development system (which also has a CT69000 on board, although its an
intel platform...) and well, it doesn't work properly. There are visible
artifacts (two vertical bars) at 24 bit pixel depth. Other modes (16bpp and
8bpp) work even less, thus being almost unusable. Can anyone point me in
the right direction? How can I find out whether the problem is in the
XFree86 chips.o driver or in the CT69000 chip / motherboard itself?
I tried to find some kind of "errata" or other experiences, but the
information on the CT69000 is very scarce, and since its mostly used for
embedded development, I figured out that some of you might know what to do
with this one or even experienced the same problem yourselves.

BTW, is there any good FAQ on how to boot Linux kernel from DINK32? I
haven't figured out any proper way to load blocks from a block device
(e.g. an IDE hard disk)

-topi


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Topi Kanerva wrote:

I'm addressing you folks at ppc-embedded because frankly, I don't know how
to find any relevant info on this issue. We are developing a single-board
solution with a CT69000 display controller.

Me too (well, a CT69030). I'm actually using a framebuffer driver for
the chip, rather than the Xserver.

If you're trying the chip on an Intel platfrom, a good first place to
look is Thomas Hhenleitner's driver:
www.visuelle-maschinen.de/ctfb/ctfb0.40.tgz

I've been working on my own 69030 driver, and at some point hope to
merge this with Thomas' driver, and possibly with the existing CT65554
driver in the kernel.

- Adrian Cox, AG Electronics

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Howdy Folks!

I'm working on the RPX Lite, and I'm exploring my options for a small web
server.  I downloaded the "GoAhead" web server, and I'm testing it out on
my host machine (Intel) first to become familiar with it and to see how
large the binary is before giving it a try on the RPX.

In the meantime, I'd thought I'd probe the list for suggested web servers
that others may have tried on embedded boards and where to find such web
servers.  Any direction to good documentation would also be greatly
appreciated.

Thanks in advance!
Jo-Ellen Mathews

---------------------------------------------------------
Jo-Ellen F. Mathews

AbsoluteValue Systems      Web:    http://www.linux-wlan.com
P.O. Box 941149            e-mail: jo-ellen@linux-wlan.com
Maitland, FL 32794-1149    Phone:  407.644.8582
USA                        Fax:    407.539.1294


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