arch/sparc: Introduce xchg16 for SPARC

SPARC supports 32 bit and 64 bit xchg right now. Add the support
for 16 bit (2 byte) xchg. This is required to support queued spinlock
feature which uses 2 byte xchg. This is achieved using 4 byte cas
instructions with byte manipulations.

Also re-arranged the code to call __cmpxchg_u32 inside xchg16.

Signed-off-by: Babu Moger <[email protected]>
Reviewed-by: Håkon Bugge <[email protected]>
Reviewed-by: Steven Sistare <[email protected]>
Reviewed-by: Shannon Nelson <[email protected]>
Reviewed-by: Jane Chu <[email protected]>
Reviewed-by: Vijay Kumar <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

0 files changed, 0 insertions, 0 deletions