TLB exception

[Rabeeh Khoury <rabeeh@galileo.co.il>]

Hi All

I'v added a code to debug the TLB misses in my kernel (2.2)
I'm running QED RM5271 in big mips mode ; I'v added the following code :

    8004de54:   3c010300        lui     $at,0x300
    8004de58:   ac200000        sw      $zero,0($at)


which simply writes zero to virtual address 0x03000000, this code is
invoked in kernel mode in kernel space and tries to write to user space.

after this I get a TLB exception with an error TLBL (TLB miss because of
load or instruction fetch) !!!!!!!!!!!!!!!
instead of TLBS.

the CP0_STATUS = 00800008
p.s. I have also strange values in the BADVADDR and CONEXT.

can any one speculate what is the problem ?
do I need to do any thing special to access user space in kernel mode ?

Regards,
Rabeeh