RE: [U-Boot-Users] U-Boot on MPC8280
Hi Wolfgang
May I ask one further question re. the BDI2000? An article on the internet states:
"You might be wondering why the BDI2000 only works with kernel-mode code and not user-land application code. The technical details are beyond the scope of this AppNote. The 10,000 foot answer is that while the BDI2000 can work with the MMU enabled, it can only work with a single continuous memory map. Kernel-mode code exists in a single continuous memory map, which is disjoint from all of the user-land process memory maps. As an example of the usefulness of this tool in production environments, the PPC porting engineers at Monta Vista Software use the BDI2000 extensively for kernel bring-up and device driver debug"
Is it true that the BDI is not suitable for user app debug? Is this a problem in practice?
Thanks
David
Dear David,
in message 0E8A20F2EB7BD7119C1F00508BB333780E5D7B@tmservermail02.t-modus.nec.co.uk you wrote:
Is it true that the BDI is not suitable for user app debug? Is this a
Yes, this is true. Well, you _can_ use it, but you have manually navigate through the kernel virtual address space to find what you are looking for. Sometimes this is necessary (typically to find kernel bugs), but this is definitely nothing to do for the average user.
problem in practice?
No, it is not.
Kernel debugging and application debugging are two separate weorlds, like kernel address space and user address space are clearly separated. There is tools for both of them: for the firmware, device drivers and kernel debugging you use the BDI2000, and for user applications you use gdbserver or gdb.
Note that this does not mean any loss of productivity: both the BDI2000 and gdbserver "speak" GDB remote protocol, so you will see absolutely the same user interface.
Best regards,
Wolfgang Denk
On Wed, Jan 07, 2004 at 03:24:46PM -0000, David Aldrich wrote:
Hi Wolfgang
May I ask one further question re. the BDI2000? An article on the internet states:
"You might be wondering why the BDI2000 only works with kernel-mode code and not user-land application code. The technical details are beyond the scope of this AppNote. The 10,000 foot answer is that while the BDI2000 can work with the MMU enabled, it can only work with a single continuous memory map. Kernel-mode code exists in a single continuous memory map, which is disjoint from all of the user-land process memory maps. As an example of the usefulness of this tool in production environments, the PPC porting engineers at Monta Vista Software use the BDI2000 extensively for kernel bring-up and device driver debug"
Is it true that the BDI is not suitable for user app debug? Is this a problem in practice?
My US$0.02...
I'm not personally aware of the issues using the BDI2000 to debug user space code. But in practice you do not need a hardware debugger to debug user space code. Just use gdb and/or gdbserver to debug your user space code.
-- Regards, George
Thanks
David
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In message 20040107155044.GA5255@mvista.com you wrote:
I'm not personally aware of the issues using the BDI2000 to debug user space code. But in practice you do not need a hardware debugger to
I guess you never tried it, did you?
You cannot just set a breakpoint at a user space virtual address...
Best regards,
Wolfgang Denk
participants (3)
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David Aldrich -
George G. Davis -
Wolfgang Denk