* Catalin Marinas [off-list ref] [110128 07:11]:

On Fri, 2011-01-28 at 13:21 +0000, Russell King - ARM Linux wrote:

quoted

On Fri, Jan 28, 2011 at 12:25:18PM +0000, Catalin Marinas wrote:

quoted

With your latest patches, do we use the TLS emulation on ARMv7 (UP) if
v6 is compiled in? If that's the case, we may have a problem - I talked
to the toolchain guys and it looks like code optimised for ARMv7 reads
the TLS register directly without going through the kuser helper. So you
may have people taking an Ubuntu filesystem (v7 only) and a pre-built
OMAP image with TLS emulation even on Cortex-A8 and things won't work as
expected.

You're really making a mountain out of TLS.

Not really, just asking for clarification as I haven't checked all your
patches recently.

quoted

If we have a v6+v6k+v7 kernel, then the way the kernel TLS code is built,
we will use the TLS register if that's available on the hardware.  If it
isn't, we will write the TLS value directly to virtual 0xffff0ffc.

So, a kernel built for v6+v6k+v7, when run on v7, will set the hardware
TLS register, and your v7 optimized binaries which access the TLS register
directly will work.  Same for v6k.

Great.

Yes AFAIK we sorted out the TLS issue already a while back for v6+v6k+v7.

Regards,

Tony