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

[Marek Vasut <marex@denx.de>]

Dear 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).

How does MANUAL_RELOC interfere with that? Eg. on ARM, it can already be shifted 
to C. Then if we made it generic enough, those MANUAL_RELOC platforms could 
simply adopt the C code.

Best regards,
Marek Vasut