Is the L4Linux running as a Fiasco.OC server?

Zeyu Mi yzmizeyu at gmail.com
Tue Mar 6 03:22:18 CET 2018


On Tue, Mar 6, 2018 at 9:20 AM, Zeyu Mi <yzmizeyu at gmail.com> wrote:

>
>
> On Tue, Mar 6, 2018 at 7:50 AM, Adam Lackorzynski <
> adam at os.inf.tu-dresden.de> wrote:
>
>> Hi,
>>
> Hi Adam,
>
>>
>> On Mon Mar 05, 2018 at 19:47:19 +0800, Zeyu Mi wrote:
>> > I am studying the implementation of the Fiasco.OC and the L4Linux.
>> >
>> > I have searched on the Internet and many papers and documents record
>> that
>> > L4Linux runs as an L4 server and
>> > any L4Linux user process is a new task, which has a new page table
>> > different from that of an L4Linux server.
>> >
>> > However, the experiment result seems to conflict with those documents.
>> When
>> > I started a new program in the
>> > L4Linux shell and used "lp" command (show present list) in JDB, I
>> noticed
>> > that there was one thread having "vcpu" state.
>> > But the resulted list did not contain any new thread or task which is
>> > related to the new program.
>> >
>> > I am very confused and wondering whether or not the implementation
>> recorded
>> > in those papers or documents are wrong or obsolete?
>>
>> Your obvservations are all right, however, 'lp' lists all threads in the
>> system but not tasks (aka address spaces). For listing tasks, use 's',
>> where you will see all the tasks for the Linux user processes.
>>
> I have tried 's' command, but there was alwasy a general protection fault.
> The following is the error
> message.
>
> KERNEL: Warning: No page-fault handler for 0xfffffffff0400008, error 0x0,
> pc fffffffff000922b
> General Protection (eip=fffffffff0042dc3, err=0000000000000000) -- jdb bug?
>
> There has been a change in model for L4Linux. With the vcpu model there
>> is only one thread (the vcpu) which is moving between the tasks for
>> execution. In the previous thread mode there has been a thread in each
>> user process. Both variants are still available through the L4Linux
>> config.
>>
> Could you kindly tell me how to enable the previous thread mode?
>

Hi Adam,
I have disabled the vcpu exeuction mode by changing the L4Linux config.
But there is one warning treated as an error when compiling the L4Linux.
Following is the detailed error log:

src/l4linux/arch/l4/kernel/main.c:3853:2: error: implicit declaration of
function ‘get_cpu_gdt_table’ [-Werror=implicit-function-declaration]
l4x_load_percpu_gdt_descriptor(get_cpu_gdt_table(_cpu));

Do you have any suggestion to fix that?

Thanks

>
>>
>>
>> Adam
>>
>> _______________________________________________
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>> l4-hackers at os.inf.tu-dresden.de
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>>
>
>
>
> --
> Best Regards
>
> Zeyu Mi
>



-- 
Best Regards

Zeyu Mi
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