Build regressions/improvements in v4.9-rc1

[Vineet Gupta]

+CC Arnd, Michal

Hi Geert, Arnd

Need some guidance here.

On 10/17/2016 12:34 AM, Geert Uytterhoeven wrote:
>> 48 error regressions:
>> >   + /home/kisskb/slave/src/arch/arc/include/asm/atomic.h: Error: bad instruction `llockd r2,[r0]':  => 476
>> >   + /home/kisskb/slave/src/arch/arc/include/asm/atomic.h: Error: bad instruction `llockd r2,[r13]':  => 475

[snip...]

>> >   + /home/kisskb/slave/src/arch/arc/include/asm/atomic.h: Error: bad instruction `scondd r4,[r8]':  => 516
>> >   + /home/kisskb/slave/src/arch/arc/include/asm/atomic.h: Error: bad instruction `scondd r6,[r3]':  => 478
> arcv2/axs103_smp_defconfig


I'm thinking how to address this correctly.

This is due to the older version of compiler.  The fix itself is trivial - add an
"call as-instr" construct in Makefile to get -DARC_TOOLS_SUPPORT_LLOCKD

However the atomic64 API variant (CONFIG_GENERIC_ATOMIC64 or arch native) which
gets included in build comes from Kconfig (ISA supports them or not). How do we
tie the Makefile info into the Kconfig.

We could trigger a build failure for invalid combinations of GENERIC_ATOMIC64 and
ARC_TOOLS_SUPPORT_LLOCKD but that would be less than ideal out of box experience.

Or the simpler solution is that kisskb upgrades the ARC GNU compiler ;-)

-Vineet