On Mon, 21 Nov 2016 19:13:55 +0000
Russell King - ARM Linux [off-list ref] wrote:

On Mon, Nov 21, 2016 at 07:46:44PM +0100, Uwe Kleine-König wrote:

quoted

Hello,

On Mon, Oct 24, 2016 at 05:05:26PM +0200, Arnd Bergmann wrote:  

quoted

This adds an asm/asm-prototypes.h header for ARM to fix the
broken symbol versioning for symbols exported from assembler
files.

In addition to the header, we have to do these other small
changes:

- move the exports from bitops.h to {change,clear,set,...}bit.S
- move the exports from csumpartialgeneric.S into the files
  including it

I couldn't find the correct prototypes for the compiler builtins,
so I went with the fake 'void f(void)' prototypes that we had
before.

This leaves the mmioset/mmiocpy function for now, as it's not
obvious how to best handle them.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>  

In my test builds of 4.9-rc5 plus

	4efca4ed05cb ("kbuild: modversions for EXPORT_SYMBOL() for asm")
	cc6acc11cad1 ("kbuild: be more careful about matching preprocessed asm ___EXPORT_SYMBOL")

(which are in -rc6) I got many warnings à la:

	WARNING: "memset" [drivers/media/usb/airspy/airspy.ko] has no CRC!

and booting the resulting kernel failed with messages of the type:

	[    3.024126] usbcore: no symbol version for __memzero
	[    3.029107] usbcore: Unknown symbol __memzero (err -22)

so hardly any module could be loaded. modprobe -f works however, but
that's not what my initramfs does.

With this patch and https://patchwork.kernel.org/patch/9392291/ ("ARM:
move mmiocpy/mmioset exports to io.c") I could compile a kernel without
CRC warnings and it boots fine. So it would be great to get these two
patches into 4.9.  

Yea, many things would be nice, but I've been unable to track the
issues here - it really didn't help _not_ being copied on the
original set of patches which introduced this mess.

Quick overview:

- asm exports changes allow EXPORT_SYMBOL to be moved into .S files,
  but they would not get modversion CRCs generated.

- The core kbuild patches to add modversions support for asm exports
  is now merged in Linus's tree from the recent kbuild tree pull.
  asm/asm-prototypes.h must contain C style declarations of the symbol
  for this to work.

- Architectures can now add their asm/asm-prototypes.h and things
  *should* start working.

- Dependency is not a hard one. If you add asm-prototypes.h before
  merging the core patches then it should not introduce any problems.

I've merged Nicolas' patch, so now we need to work out what to do
with the remaining bits - which I guess are the asm-prototypes.h
and the mmio* bits.  I'm not aware of what's happening with the
patches that they depend on (which is why I recently asked the
question - again, I seem to be completely out of the loop due to
lack of Cc's).

So I'm just throwing my hands up and saying "I don't know what to
do" at this stage.

I don't think you have missed much since last it came up, it's just
taken a bit of time to get the details right and get it merged.

Not sure what your tree looks like, but if you merge this patch 1/2
plus 2a/2 or 2b/2 into upstream, then ARM should be working.

Thanks,
Nick