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Re: [lwip-users] lwip and MPU (FreeRTOS-MPU)
From: |
Martin Velek |
Subject: |
Re: [lwip-users] lwip and MPU (FreeRTOS-MPU) |
Date: |
Thu, 30 Aug 2012 11:33:05 +0200 |
Hi,
do you mean this situation?
Thread A = tcpip thread - stack protected by MPU, only A and
privileged mode can access it
Thread B = user thread - stack protected by MPU, only B and privileged
mode can access it
Thread A{
message = wait_for_message_from_A();
...
(dereference)message.pointer_to_somewhere = true; <----- HERE is the
MPU exception
send_message_back_to_A(message);
}
Thread B{
bool message_OK;
message.pointer_to_somewhere = (reference)message_OK;
send_message_to_B(message)
message = wait_for_message_status_from_A();
if(true == message_OK) ....
}
Remark: Probably a more complex structure is referenced, not the bool type.
In that case, there is no answer to your question, if you want to use
the MPU until a new version of lwip is released.
Martin
On Wed, Aug 29, 2012 at 4:50 AM, jblackarty <address@hidden> wrote:
> Hi all,
>
> I've ported lwip to FreeRTOS-MPU (ARM Cortex-M3, GCC) and suddenly
> found that lwip design violates FreeRTOS memory access
> restrictions. The problem is that lwip tcpip thread accesses local
> variable allocated on stack of application thread which uses Netconn
> API. FreeRTOS-MPU protects thread stacks because stack corruption
> (made by other threads) can corrupt freertos kernel data and thus
> cause crash of whole system
> LwIP is most unreliable (because most complex) component in my
> system. Therefore, it's first candidate to have most rectricted access
> rights in my system. Ironically, it happened that I'm forced to give
> it access to application thread stacks and thus make it the only
> component which may cause whole system crash ! And seems like it does
> it already in my tests, but I'm not sure so far because I didn't found
> that it's lwip who does it (it's only a week passed since I started
> debbugging which driving me crazy).
> I have absolutely no idea how to solve it keeping lwip code
> unmodified. What do you think about it ?
>
> Regards,
> Artem Pisarenko
>
>
> _______________________________________________
> lwip-users mailing list
> address@hidden
> https://lists.nongnu.org/mailman/listinfo/lwip-users
- [lwip-users] lwip and MPU (FreeRTOS-MPU), jblackarty, 2012/08/28
- Re: [lwip-users] lwip and MPU (FreeRTOS-MPU),
Martin Velek <=
- Re: [lwip-users] lwip and MPU (FreeRTOS-MPU), jblackarty, 2012/08/30
- Re: [lwip-users] lwip and MPU (FreeRTOS-MPU), yuantu Huang, 2012/08/31
- Re: [lwip-users] lwip and MPU (FreeRTOS-MPU), jblackarty, 2012/08/31
- Re: [lwip-users] lwip and MPU (FreeRTOS-MPU), Richard Barry, 2012/08/31
- Re: [lwip-users] lwip and MPU (FreeRTOS-MPU), jblackarty, 2012/08/31