linux/arch/frv/lib/atomic64-ops.S
Peter Zijlstra b0d8003ef4 frv: Rewrite atomic implementation
Mostly complete rewrite of the FRV atomic implementation, instead of
using assembly files, use inline assembler.

The out-of-line CONFIG option makes a bit of a mess of things, but a
little CPP trickery gets that done too.

FRV already had the atomic logic ops but under a non standard name,
the reimplementation provides the generic names and provides the
intermediate form required for the bitops implementation.

The slightly inconsistent __atomic32_fetch_##op naming is because
__atomic_fetch_##op conlicts with GCC builtin functions.

The 64bit atomic ops use the inline assembly %Ln construct to access
the low word register (r+1), afaik this construct was not previously
used in the kernel and is completely undocumented, but I found it in
the FRV GCC code and it seems to work.

FRV had a non-standard definition of atomic_{clear,set}_mask() which
would work types other than atomic_t, the one user relying on that
(arch/frv/kernel/dma.c) got converted to use the new intermediate
form.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-07-27 14:06:23 +02:00

69 lines
1.9 KiB
ArmAsm

/* kernel atomic64 operations
*
* For an explanation of how atomic ops work in this arch, see:
* Documentation/frv/atomic-ops.txt
*
* Copyright (C) 2009 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <asm/spr-regs.h>
.text
.balign 4
###############################################################################
#
# uint64_t __xchg_64(uint64_t i, uint64_t *v)
#
###############################################################################
.globl __xchg_64
.type __xchg_64,@function
__xchg_64:
or.p gr8,gr8,gr4
or gr9,gr9,gr5
0:
orcc gr0,gr0,gr0,icc3 /* set ICC3.Z */
ckeq icc3,cc7
ldd.p @(gr10,gr0),gr8 /* LDD.P/ORCR must be atomic */
orcr cc7,cc7,cc3 /* set CC3 to true */
cstd.p gr4,@(gr10,gr0) ,cc3,#1
corcc gr29,gr29,gr0 ,cc3,#1 /* clear ICC3.Z if store happens */
beq icc3,#0,0b
bralr
.size __xchg_64, .-__xchg_64
###############################################################################
#
# uint64_t __cmpxchg_64(uint64_t test, uint64_t new, uint64_t *v)
#
###############################################################################
.globl __cmpxchg_64
.type __cmpxchg_64,@function
__cmpxchg_64:
or.p gr8,gr8,gr4
or gr9,gr9,gr5
0:
orcc gr0,gr0,gr0,icc3 /* set ICC3.Z */
ckeq icc3,cc7
ldd.p @(gr12,gr0),gr8 /* LDD.P/ORCR must be atomic */
orcr cc7,cc7,cc3
subcc gr8,gr4,gr0,icc0
subcc.p gr9,gr5,gr0,icc1
bnelr icc0,#0
bnelr icc1,#0
cstd.p gr10,@(gr12,gr0) ,cc3,#1
corcc gr29,gr29,gr0 ,cc3,#1 /* clear ICC3.Z if store happens */
beq icc3,#0,0b
bralr
.size __cmpxchg_64, .-__cmpxchg_64