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locking/atomics/arm64: Replace our atomic/lock bitop implementations with asm-generic 

The <asm-generic/bitops/{atomic,lock}.h> implementations are built around
the atomic-fetch ops, which we implement efficiently for both LSE and
LL/SC systems. Use that instead of our hand-rolled, out-of-line bitops.S.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arm-kernel@lists.infradead.org
Cc: yamada.masahiro@socionext.com
Link: https://lore.kernel.org/lkml/1529412794-17720-9-git-send-email-will.deacon@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
hifive-unleashed-5.1
Will Deacon 2018-06-19 13:53:13 +01:00 committed by Ingo Molnar
parent 84c6591103
commit 7c8fc35dfc
3 changed files with 3 additions and 89 deletions
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14
arch/arm64/include/asm/bitops.h
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@ -17,22 +17,11 @@
#define __ASM_BITOPS_H
#include <linux/compiler.h>
#include <asm/barrier.h>
#ifndef _LINUX_BITOPS_H
#error only <linux/bitops.h> can be included directly
#endif
/*
* Little endian assembly atomic bitops.
*/
extern void set_bit(int nr, volatile unsigned long *p);
extern void clear_bit(int nr, volatile unsigned long *p);
extern void change_bit(int nr, volatile unsigned long *p);
extern int test_and_set_bit(int nr, volatile unsigned long *p);
extern int test_and_clear_bit(int nr, volatile unsigned long *p);
extern int test_and_change_bit(int nr, volatile unsigned long *p);
#include <asm-generic/bitops/builtin-__ffs.h>
#include <asm-generic/bitops/builtin-ffs.h>
#include <asm-generic/bitops/builtin-__fls.h>
@ -44,8 +33,9 @@ extern int test_and_change_bit(int nr, volatile unsigned long *p);
#include <asm-generic/bitops/sched.h>
#include <asm-generic/bitops/hweight.h>
#include <asm-generic/bitops/lock.h>
#include <asm-generic/bitops/atomic.h>
#include <asm-generic/bitops/lock.h>
#include <asm-generic/bitops/non-atomic.h>
#include <asm-generic/bitops/le.h>

2
arch/arm64/lib/Makefile
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@ -1,5 +1,5 @@
# SPDX-License-Identifier: GPL-2.0
lib-y := bitops.o clear_user.o delay.o copy_from_user.o \
lib-y := clear_user.o delay.o copy_from_user.o \
copy_to_user.o copy_in_user.o copy_page.o \
clear_page.o memchr.o memcpy.o memmove.o memset.o \
memcmp.o strcmp.o strncmp.o strlen.o strnlen.o \

76
arch/arm64/lib/bitops.S
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@ -1,76 +0,0 @@
/*
* Based on arch/arm/lib/bitops.h
*
* Copyright (C) 2013 ARM Ltd.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/linkage.h>
#include <asm/assembler.h>
#include <asm/lse.h>
/*
* x0: bits 5:0 bit offset
* bits 31:6 word offset
* x1: address
*/
.macro bitop, name, llsc, lse
ENTRY( \name )
and w3, w0, #63 // Get bit offset
eor w0, w0, w3 // Clear low bits
mov x2, #1
add x1, x1, x0, lsr #3 // Get word offset
alt_lse " prfm pstl1strm, [x1]", "nop"
lsl x3, x2, x3 // Create mask
alt_lse "1: ldxr x2, [x1]", "\lse x3, [x1]"
alt_lse " \llsc x2, x2, x3", "nop"
alt_lse " stxr w0, x2, [x1]", "nop"
alt_lse " cbnz w0, 1b", "nop"
ret
ENDPROC(\name )
.endm
.macro testop, name, llsc, lse
ENTRY( \name )
and w3, w0, #63 // Get bit offset
eor w0, w0, w3 // Clear low bits
mov x2, #1
add x1, x1, x0, lsr #3 // Get word offset
alt_lse " prfm pstl1strm, [x1]", "nop"
lsl x4, x2, x3 // Create mask
alt_lse "1: ldxr x2, [x1]", "\lse x4, x2, [x1]"
lsr x0, x2, x3
alt_lse " \llsc x2, x2, x4", "nop"
alt_lse " stlxr w5, x2, [x1]", "nop"
alt_lse " cbnz w5, 1b", "nop"
alt_lse " dmb ish", "nop"
and x0, x0, #1
ret
ENDPROC(\name )
.endm
/*
* Atomic bit operations.
*/
bitop change_bit, eor, steor
bitop clear_bit, bic, stclr
bitop set_bit, orr, stset
testop test_and_change_bit, eor, ldeoral
testop test_and_clear_bit, bic, ldclral
testop test_and_set_bit, orr, ldsetal