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Message-Id: <1518708575-12284-5-git-send-email-will.deacon@arm.com>
Date: Thu, 15 Feb 2018 15:29:34 +0000
From: Will Deacon <will.deacon@....com>
To: linux-kernel@...r.kernel.org
Cc: linux-arm-kernel@...ts.infradead.org, peterz@...radead.org,
mingo@...nel.org, Will Deacon <will.deacon@....com>
Subject: [RFC PATCH 4/5] arm64: Replace our atomic bitops implementation with asm-generic
The asm-generic/bitops/atomic.h implementation is 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@....com>
---
arch/arm64/include/asm/bitops.h | 13 +------
arch/arm64/lib/Makefile | 2 +-
arch/arm64/lib/bitops.S | 76 -----------------------------------------
3 files changed, 2 insertions(+), 89 deletions(-)
delete mode 100644 arch/arm64/lib/bitops.S
diff --git a/arch/arm64/include/asm/bitops.h b/arch/arm64/include/asm/bitops.h
index 9c19594ce7cb..817233fbf249 100644
--- a/arch/arm64/include/asm/bitops.h
+++ b/arch/arm64/include/asm/bitops.h
@@ -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 +33,8 @@ 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/non-atomic.h>
#include <asm-generic/bitops/le.h>
diff --git a/arch/arm64/lib/Makefile b/arch/arm64/lib/Makefile
index 4e696f96451f..73095a04c0ad 100644
--- a/arch/arm64/lib/Makefile
+++ b/arch/arm64/lib/Makefile
@@ -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 \
diff --git a/arch/arm64/lib/bitops.S b/arch/arm64/lib/bitops.S
deleted file mode 100644
index 43ac736baa5b..000000000000
--- a/arch/arm64/lib/bitops.S
+++ /dev/null
@@ -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
--
2.1.4
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