sh: add AT_HWCAP flag for J-Core cas.l instruction
authorRich Felker <dalias@libc.org>
Fri, 22 Apr 2016 23:29:13 +0000 (23:29 +0000)
committerRich Felker <dalias@libc.org>
Fri, 5 Aug 2016 03:29:32 +0000 (03:29 +0000)
commit834da197058bebcb343320dafb8b62d416d4038c
tree86014306af44c06b216683dfbc20aa2a8e997b18
parent5a846abad07f6f30adfa3e46c5c7a47d2e7b1e63
sh: add AT_HWCAP flag for J-Core cas.l instruction

The J-Core cpu has, as an ISA extension, an atomic compare-and-swap
instruction cas.l which applications need to use (instead the imask or
gusa atomic models, which are fundamentally limited to UP) for
synchronization in order to be compatible with SMP systems. Provide a
hwcap flag so that it's possible to do runtime selection and support
both.

Signed-off-by: Rich Felker <dalias@libc.org>
arch/sh/include/uapi/asm/cpu-features.h
arch/sh/kernel/cpu/sh2/probe.c