Re: [added to the 4.1 stable tree] ARM: OMAP2+: Fix l2_inv_api_params for rodata

On Thu, Feb 11, 2016 at 07:48:10AM -0800, Tony Lindgren wrote:

Hi,

* Russell King - ARM Linux [off-list ref] [160211 02:43]:

quoted

Yes, this isn't going to work if it is copied out of the DDR, because
moving the data to the .data section and introducing a PC relative
access to it will make the code expect to access data at a relative
offset from the SRAM.

Sascha, please drop this for now.

Hmm did I miss something? Since commit 46e130d298a3 ("ARM: pm: omap3:
run the ASM sleep code from DDR") we only run minimal parts of the
code in SRAM. Naturally if any SRAM code uses PC relative access things
won't work.

Here are the only pieces running in SRAM:

- omap3_do_wfi running in SRAM only for retention idle as off
  idle restores DDR for us

- For HS omaps, save_secure_ram_context is already in .data as it's
  only run in SRAM

- For some revisions, we have es3_sdrc_fix dynamically copied to
  SRAM

If there are other places that I've missed, please let me know and
I'll take a look ASAP!

Hmm, ok, I missed that.  It looks fine, but now that I'm looking deeper,
I'm wondering what the point of this particular change is.

From what I can see, you're moving both l2dis_3630 and l2_inv_api_params

into the .data section, and adding extra complication to access those in
a position-relative manner.  However, I'm unable to locate anything which
writes to either of these: they're only read from - nothing can, they're
not even global symbols, so aren't referencable outside of sleep34xx.S.

So I don't see why this should be Cc'd for stable kernels, since as far
as I can see, it's not fixing any bug.

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