[U-Boot] [PATCH] env_mmc: fix buffer allocation for armv7

[Tom Rini]

On Mon, Oct 07, 2013 at 03:58:02PM +0200, Wolfgang Denk wrote:
> Dear Tom,
> 
> In message <20131007122020.GT15917 at bill-the-cat> you wrote:
> > 
> > > But malloc() is drawing from the very same resource as the stack, even
> > > more so: with a buffer on the stack, the memory isfreed completeky
> > > upon return from the fucntion, with no reminders left.  With malloc()
> > > you need to statically allocate the malloc pool size for the whole
> > > runtime, and allocating the buffers may fragment tha area, so even
> > > after freeing the buffers there is less space left for other purposes.
> > > 
> > > Especially in memory-tight situations you want to avoid malloc().
> >
> > Ah, but in these cases we don't have stack room, period.  We have a
> > malloc pool.  So unless we make SPL move its stack pointer into DDR from
> > wherever we set the initial one to, the other option here is to just
> > restrict real env support to NOR (and we already don't allow embedded
> > env, since that's embedded within U-Boot, not SPL).
> 
> Well, if we have DDR such that we can use it for the malloc arena, we
> also should use it for the stack.  Or is there a good reason for not
> doing this?  It would solve all these issues at the root...

Making SPL more complex for everyone?  We would need to do a fairly
good-sized re-jigger of SPL to setup and swap around stack pointers like
we do in full U-Boot.

-- 
Tom
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