[okl4-developer] okl4 faults on arm1136

[Ashish Bijlani]

I saw the stack setup in crt0.spp under arch/arm/libs/c/crt. However,
the control doesn't go to "_start" of rootserver. The system faults as
soon as last instruction in "initial_to_user" is executed. This means
arch.context in the tcb of roottask is not being setup correctly.
"arch.context" is what is loaded in "sp" in the function
"initial_to_user". Does this make sense? What could possibly be wrong
here?

The rootserver mappings are fine I suppose.

Debug: Setting up rootserver mappings: V:3000 P:8012a000 S:1000 (0)
Debug: Setting up rootserver mappings: V:100000 P:801a0000 S:39984 (1)
Debug: Setting up rootserver mappings: V:142000 P:80602000 S:3e02c (2)
Debug: Setting up rootserver mappings: V:2000 P:80123000 S:1000 (3)
Debug: Setting up rootserver mappings: V:200000 P:80700000 S:100000 (4)

-Ashish

On Tue, Jul 22, 2008 at 10:42 PM, Geoffrey Lee <glee at ok-labs.com> wrote:
> On Tue, Jul 22, 2008 at 09:13:52PM -0500, Ashish Bijlani wrote:
>> Hi Geoffrey,
>>
>> How do I verify if the bootinfo is being patched correctly? Is there
>> some linker script that does it?
>
>
> This patching is done by elfweaver.  Have you read the crt0?  It
> contains a comment which should give good hints on how the
> stack is setup for the rootserver.
>
>>
>> Thanks,
>> Ashish
>
>        -gl
>
>>
>> On Tue, Jul 22, 2008 at 9:04 PM, Geoffrey Lee <glee at ok-labs.com> wrote:
>> > On Tue, Jul 22, 2008 at 08:59:39PM -0500, Ashish Bijlani wrote:
>> >> Here are more debugging messages:
>> >>
>> >> Debug: Setting up rootserver mappings: V:3000 P:8012a000 S:1000 (0)
>> >> Debug: Setting up rootserver mappings: V:100000 P:801a0000 S:39984 (1)
>> >> Debug: Setting up rootserver mappings: V:142000 P:80602000 S:3e02c (2)
>> >> Debug: Setting up rootserver mappings: V:2000 P:80123000 S:1000 (3)
>> >> Debug: Setting up rootserver mappings: V:200000 P:80700000 S:100000 (4)
>> >>
>> >> The system doesn't seem to be loading rootserver info properly in the
>> >> function "asm_switch_to".
>> >> I guess the stack pointer "sp" in function "asm_switch_to" is not
>> >> being setup correctly.
>> >>
>> >> I see the following line commented out in function "init_root_servers"
>> >>
>> >> /** @todo FIXME: Enable once user-level crt0's are fixed - awiggins. */
>> >> //tcb->set_user_sp((addr_t)(server_info->sp));
>> >
>> >
>> > Hi Ashish,
>> >
>> > Please have a look at the user-level crt0.  You will find the sp for the
>> > roottask is set to zero, and the stack address is obtained from
>> > the bootinfo.
>> >
>> >>
>> >> Why is the stack pointer not set as per the rootserver info struct?
>> >>
>> >> Function "asm_switch_to" passes STACK_TOP as the stack pointer to the
>> >> roottask. Could this be the reason?
>> >
>> >
>> > No, the behavior of asm_switch_to() is correct.  What you see in
>> > asm_switch_to() is the kernel stack pointer being reset to STACK_TOP
>> > and has nothing to do with the value of the user thread's stack pointer.
>> >
>> >
>> >>
>> >> -Ashish
>> >
>> >        -gl
>> >
>> >>
>> >>
>> >> On Tue, Jul 22, 2008 at 8:30 PM, Ashish Bijlani
>> >> <ashish.bijlani at gmail.com> wrote:
>> >> > Hi,
>> >> >
>> >> > OKL4 faults on arm1136jfs when starting the roottask at addr
>> >> > 0xf000e0c0 with stack top = 0x3f8 and stack size 1024 bytes. Any idea
>> >> > why? I'm loading okl4 at 0x8010 0000 (start of the RAM).
>> >> >
>> >> > Below are the boot msgs:
>> >> >
>> >> > Uncompressing OKL4.....................done, booting the kernel.
>> >> > Info: Interrupt Controller found at 0xf90fe000 (rev. 2.1) with 96 interrupts
>> >> > OKL4 - (provider: Open Kernel Labs) built on Jul 22 2008 04:23:06
>> >> > using gcc version 3.4.4.
>> >> > Initializing kernel debugger...
>> >> > Initializing interrupts...
>> >> > Info: Disabling FIQs
>> >> > Processor Id => 4107b362: v6, ARM1136, rev 2
>> >> > VFP CoProcessor Supported
>> >> > VFP System Id => 410120b4: ARM, Format 1, Precision Single+Double,
>> >> > VFPv2, PartNo 20, Rev 5,
>> >> > Initializing timer...
>> >> > Info: Unmasking IRQ 37
>> >> > TLB lock: vectors @ ffff0000
>> >> > TLB lock: utcb @ ff000000
>> >> > TLB lock: kernel @ f0000000
>> >> > Locked kernel into TLB
>> >> > Init mutexids for 256 mutexs
>> >> > Init clistids for 16 clists
>> >> > Initialising scheduler...
>> >> > Switching to idle thread
>> >> > Debug: Moving to addr f00079e4 with stack f001f3f8
>> >> > Initializing root servers
>> >> > root-servers: utcb_area: eff00100 (64KB)
>> >> > creating root server (00000001)
>> >> > Debug: System Started
>> >> > Debug: Current Thread ID = 0x1d1e1d1e
>> >> > Debug: Next Thread ID = 0x00000001
>> >> >
>> >> > Thanks,
>> >> > Ashish
>> >> >
>> >>
>> >> _______________________________________________
>> >> Developer mailing list
>> >> Developer at okl4.org
>> >> https://lists.okl4.org/mailman/listinfo/developer
>> >>
>> >
>> > --
>> >
>> >
>>
>
> --
>
>