Howto get __log_buf on a Xilinx FPGA

Ricardo Ayres Severo severo.ricardo at
Wed Feb 13 06:30:38 EST 2008

Hi all,

I'm trying to boot linux 2.6.24 on a XUP Virtex II Pro evaluation
board. It uncompresses ok but doesn't show nothing more on the
console. I tried to change the console to ttyS0 and ttyUL0. Now I want
to see the __log_buf but I don't if I am doing it the right way, it
only returns trash. What I'm doing is the following:

$ grep __log_buf
c01f3d5c b __log_buf

$ xmd -xmp system.xmp -opt etc/xmd_ppc405_0.opt
(xmd starts ok, mdm is not enabled)

$ powerpc-eabi-gdb arch/ppc/boot/images/zImage.elf
(click on run, the image is loaded and started)

this is the output on the terminal:
---output start---
loaded at:     00400000 004F119C

board data at: 00000000 0000007C

relocated to:  00404048 004040C4

zimage at:     00404E34 004EE12C

avail ram:     004F2000 7C9E2378

Linux/PPC load: console=ttyS0,9600

Uncompressing Linux...done.

Now booting the kernel
---output end---

after a while I stop the debugger and type rst in xmd.
then I ask gdb to dump the memory from position 0x1f3d5c to 0x1f3fff
and only trash is returned.

What am I doing wrong? Or the kernel really isn't being executed?


Ricardo Ayres Severo <severo.ricardo at>

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