Re: Misaligned read/write of memory by GDB

[Dave Brolley <brolley at redhat dot com>]

Frank Ch. Eigler wrote:

> > I thought about the possibility of fixing existing memory targets to 
> > handle misaligned access, either by implementing support, returning 
> > sid::bus::misaligned, or whatever else might be appropriate. 
> >    
>
> How many offenders (that did neither) did you encounter?
Just one. The cache component. It silently reads directly from the 
backing memory, thus (potentially) returning the wrong value.

> > However it occurred to me that this would require implementors of all
> > future memory targets to be aware of potential GDB access of this
> > type. [...]
> >    
>
> True, except that such accesses could originate elsewhere - a simulated
> CPU, or a gloss component, for example.
>  
I guess one could argue that all complete component implementations 
should handle all possible input possibilities. The failure was not 
obvious in my case because of the silent misbehavior of the cache 
component. I guess I was just wanting to prevent a similar misfortune 
from happening to someone else (or me again!) in the future.

Your gloss example convinces me that the cache component should be 
fixed, however. Once done, I can implement the GDB access in the way 
you've suggested.

Dave