[U-Boot] [PATCH v2 01/11] ARM: fix relocation on ARM926EJS

[Tom Rini]

On Mon, Sep 17, 2012 at 07:26:06PM +0200, Marek Vasut wrote:
> Dear Tom Rini,
> 
> > On Sun, Sep 16, 2012 at 05:36:47PM +0200, Marek Vasut wrote:
> > > Dear Jos? Miguel Gon?alves,
> > > 
> > > > On 09/16/2012 11:06 AM, Marek Vasut wrote:
> > > > > Dear Jos? Miguel Gon?alves,
> > > > > 
> > > > >> On 09/15/2012 07:03 PM, Marek Vasut wrote:
> > > > >>> Dear Jos? Miguel Gon?alves,
> > > > >>> 
> > > > >>>> Jumping to board_init_r is not performed due to a bug on address
> > > > >>>> computation.
> > > > >>> 
> > > > >>> Is your CONFIG_SYS_TEXT_BASE configured correctly? I don't detect
> > > > >>> any misbehavior on my arm926 boards.
> > > > >> 
> > > > >> Maybe because you are not using it to build an SPL?
> > > > > 
> > > > > I do ... and I use CONFIG_SPL_TEXT_BASE properly .
> > > > > 
> > > > >> Please check the same chunk of code in other start.S for arm1176 and
> > > > >> armv7. They have the same code that I put for arm926ejs.
> > > > > 
> > > > > Please wait and please first explain what is the issue.
> > > > 
> > > > The issue is what I've explained in the patch comments.
> > > 
> > > "Jumping to board_init_r is not performed due to a bug on address
> > > computation."
> > > 
> > > Ok, I don't know how to replicate the bug from this comment or what
> > > effects it causes or ... well, anything. So please, try to be more
> > > elaborate in your patch description next time. Anyway ..
> > > 
> > > > Without this
> > > > change the code never reaches board_init_r in the SPL and I think I
> > > > have all the configurations correctly set.
> > > 
> > > I wonder why you'd ever want to reach board_init_r in the SPL. SPL is
> > > there only to load the real U-Boot from whatever media, so you usually
> > > use either NAND SPL
> > 
> > Here's a good point for me to jump in, I think.  There's two things to
> > understand:
> > - In the current in-tree SPL implementations the code flow is
> >   board_init_f calls relocate_code() to clear the BSS _and_ get our jump
> >   to board_init_r.  It does not actually relocate the running U-Boot,
> >   just clears the BSS.  board_init_r is what calls the things to load
> >   and boot the next stage (U-Boot or Linux).
> > 
> > - In my series this has been changed slightly to be board_init_f calls
> >   memset and then board_init_r directly.  So this patch should not be
> >   needed once rebased on that series.
> 
> Do we need to do all the relocation in assembler code btw? Can it not be moved 
> into C code and made generic across all platforms (module the stack adjustment 
> and a few minor things) ?

I think people have posted patches for this before and yes, once
CONFIG_NEEDS_MANUAL_RELOC dies it should be all possible to do in C, so
long as it doesn't grow in size or doesn't grow in size that would be
problematic (remember the 4kb people).

-- 
Tom