linux.git/arch/mips/kernel/cmpxchg.c, branch v4.13 Linux kernel source tree MIPS: cmpxchg: Implement 1 byte & 2 byte cmpxchg() 2017-06-29T00:42:25+00:00 Paul Burton paul.burton@imgtec.com 2017-06-10T00:26:40+00:00 3ba7f44d2b19166b34031db48ce613d1bddbd384 Implement support for 1 & 2 byte cmpxchg() using read-modify-write atop a 4 byte cmpxchg(). This allows us to support these atomic operations despite the MIPS ISA only providing 4 & 8 byte atomic operations. This is required in order to support queued rwlocks (qrwlock) in a later patch, since these make use of a 1 byte cmpxchg() in their slow path. Signed-off-by: Paul Burton <paul.burton@imgtec.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/16355/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org> 
Implement support for 1 & 2 byte cmpxchg() using read-modify-write atop
a 4 byte cmpxchg(). This allows us to support these atomic operations
despite the MIPS ISA only providing 4 & 8 byte atomic operations.

This is required in order to support queued rwlocks (qrwlock) in a later
patch, since these make use of a 1 byte cmpxchg() in their slow path.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16355/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
MIPS: cmpxchg: Implement 1 byte & 2 byte xchg() 2017-06-29T00:42:25+00:00 Paul Burton paul.burton@imgtec.com 2017-06-10T00:26:39+00:00 b70eb30056dc84568f3d32440d9be6a558025843 Implement 1 & 2 byte xchg() using read-modify-write atop a 4 byte cmpxchg(). This allows us to support these atomic operations despite the MIPS ISA only providing for 4 & 8 byte atomic operations. This is required in order to support queued spinlocks (qspinlock) in a later patch, since these make use of a 2 byte xchg() in their slow path. Signed-off-by: Paul Burton <paul.burton@imgtec.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/16354/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org> 
Implement 1 & 2 byte xchg() using read-modify-write atop a 4 byte
cmpxchg(). This allows us to support these atomic operations despite the
MIPS ISA only providing for 4 & 8 byte atomic operations.

This is required in order to support queued spinlocks (qspinlock) in a
later patch, since these make use of a 2 byte xchg() in their slow path.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16354/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>