BDI2000 PTEs

Rudolf Ladyzhenskii rudolf.ladyzhenskii at
Thu Nov 29 11:35:34 EST 2001

 Thanks a lot, Dan,

It is working now.

The only thing you omitted is allocation of abatro_pteptrs variable.
In same file following has to be added as well:

After lines
    .space 512

Add following:

/* Room for two PTE table poiners, usually the kernel and current user
 * pointer to their respective root page table (pgdir).
        .space  8


-----Original Message-----
From: Dan Malek
To: Rudolf Ladyzhenskii
Cc: 'linuxppc-embedded at'
Sent: 11/28/01 5:19 PM
Subject: Re: BDI2000 PTEs

Rudolf Ladyzhenskii wrote:

> All I need for kernel debugging is BAT only translation. I cleared it
> according to BDI2000 manual.

Ummm....I think you need more than that for debugging loadable modules.
The BAT translation won't work for loadable modules, you have to find
all of their code and data through page tables.

> I looked at 2.4.14 kernel. It only has BDI2000 support in file
> /arch/ppc/kernel/head_8xx.S

Well hell....I wonder why they were never updated in 2.4.14.  Take
a look at the PowerPC development kernels, then.

> Which lines do I have to add?

Add this right after the 'bl load_up_mmu':

        /* Add helper information for the Abatron bdiGDB debugger.
         * We do this here because we know the mmu is disabled, and
         * will be enabled for real in just a few instructions.
        lis     r5, abatron_pteptrs at h
        ori     r5, r5, abatron_pteptrs at l
        stw     r5, 0xf0(r0)    /* This much match your Abatron config
        lis     r6, swapper_pg_dir at h
        ori     r6, r6, swapper_pg_dir at l
        tophys(r5, r5)
        stw     r6, 0(r5)

Good Luck.

	-- Dan

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