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Re: [ECOS] printf does not work in user mode on Arm E7T
- From: Andrew Lunn <andrew dot lunn at ascom dot ch>
- To: Pierre Habraken <Pierre dot Habraken at imag dot fr>
- Cc: newlib at sources dot redhat dot com, ecos-discuss at sources dot redhat dot com
- Date: Wed, 26 Mar 2003 09:20:37 +0100
- Subject: Re: [ECOS] printf does not work in user mode on Arm E7T
- References: <3E8162A7.57292D43@imag.fr>
This is not an area of eCos i know, so this is more of a guess.
How is your MMU setup? Maybe in user mode the MMU is stopping access
to the memory where the serial port is, or some other critical region
of memory. What is it trying to do when you get a BUS error? That may
give you a clue.
Andrew
On Wed, Mar 26, 2003 at 09:19:51AM +0100, Pierre Habraken wrote:
> Hello,
>
> For demonstration purpose, I have inserted printf calls in a program
> running on an Arm Evaluator 7T (controlled by gdb as a remote target).
> The program is linked against newlib libc but and it uses redboot
> syscalls (redboot.specs).
> Some parts of the program runs in svc mode (cpsr = 0x13), other parts
> run in usr mode (cpsr = 0x10), each mode using its own stack.
> When printf is called with the processor being in svc mode, the
> corresponding output is displayed in the gdb console and the program
> continues then with its execution.
> When printf is called with the processor being in usr mode, nothing is
> displayed in the gdb console and the program hangs or raises a BUS
> ERROR.
> Could someone explain me what printf would not work in user mode ?
>
> Thanks in advance for any help.
>
> Pierre
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