[U-Boot] [PATCH v2 2/9] make the hwconfig buffer deeper

[York Sun]

On Mon, 2011-01-03 at 22:11 +0100, Wolfgang Denk wrote:
> Dear York Sun,
> 
> In message <1294085287.24386.52.camel at oslab-l1> you wrote:
> >
> > > Please explain 1) why this is needed and 2) what it has to do with
> > > running "at" (from?) flash?
> > > 
> > > hwconfig is intended for simple h/w configurations.  In which case do
> > > you need more than 128 characters for such settings?  And is this
> > > really needed / reasonable?
> > 
> > First of all, I don't need more than 128 characters for hwconfig. I
> > think the buggy code makes the buffer less usable.
> 
> Hm... I have no idea whish sort of "buggy code" you are referring to
> here, but in this case we shoul start and fix that buggy code, right?

Making a buffer in a function's stack and make use of it out of the
scope, that's the buggy code I am referring. 

> 
> > If you look into the common/hwconfig.c, you will notice the _current_
> > code uses the stack as temporary memory to hold the variable. Even I
> > don't agree with this way, I don't have a quick fix either. There may be
> 
> What's wrong with putting it on the stack?  This prevents a permanent
> allocation, so the memory can easily be reused once that function
> returns.

How can the content be guaranteed? The stack can be trashed when the
function returns.

> 
> > two ways or more to fix it. One is to create wrapper functions to deal
> > with pre-relocation and post-relocation functions. Another way is to
> > allocate more space in gd. Which way do you think is better?
> 
> You fail to explain why we should change anything when you "don't need
> more than 128 characters for hwconfig" in the first place?

I don't need more than 128 characters. However, the stack is trashed by
other functions. I have to push the stack deeper to keep the content
unchanged. I am not happy with it.

York