tree f05689b6e06bbf9c03499ce2ad8728546a0b54cc
parent 97d9f969161d79e6a4bba247e67ce731ff861f79
author Babu Moger <babu.moger@oracle.com> 1495670112 -0600
committer David S. Miller <davem@davemloft.net> 1495739211 -0700

arch/sparc: Introduce cmpxchg_u8 SPARC

SPARC supports 32 bit and 64 bit cmpxchg right now. Add support
for 8 bit (1 byte) cmpxchg. This is required to support queued
rwlocks feature  which uses 1 byte cmpxchg.

The function __cmpxchg_u8 here uses the 4 byte cas instruction with a
byte manipulation to achieve 1 byte cmpxchg.

Signed-off-by: Babu Moger <babu.moger@oracle.com>
Reviewed-by: Håkon Bugge <haakon.bugge@oracle.com>
Reviewed-by: Steve Sistare <steven.sistare@oracle.com>
Reviewed-by: Shannon Nelson <shannon.nelson@oracle.com>
Reviewed-by: Jane Chu <jane.chu@oracle.com>
Reviewed-by: Vijay Kumar <vijay.ac.kumar@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>