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c47d6a04e6
We're currently relying on unpredictable behaviour in our testops (test_and_*_bit), as stxr is unpredictable when the status register and the source register are the same This patch changes reallocates the status register so as to bring us back into the realm of predictable behaviour. Boot tested on an AEMv8 model. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
71 lines
1.6 KiB
ArmAsm
71 lines
1.6 KiB
ArmAsm
/*
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* Based on arch/arm/lib/bitops.h
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*
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* Copyright (C) 2013 ARM Ltd.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <linux/linkage.h>
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#include <asm/assembler.h>
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/*
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* x0: bits 5:0 bit offset
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* bits 63:6 word offset
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* x1: address
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*/
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.macro bitop, name, instr
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ENTRY( \name )
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and x3, x0, #63 // Get bit offset
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eor x0, x0, x3 // Clear low bits
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mov x2, #1
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add x1, x1, x0, lsr #3 // Get word offset
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lsl x3, x2, x3 // Create mask
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1: ldxr x2, [x1]
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\instr x2, x2, x3
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stxr w0, x2, [x1]
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cbnz w0, 1b
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ret
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ENDPROC(\name )
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.endm
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.macro testop, name, instr
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ENTRY( \name )
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and x3, x0, #63 // Get bit offset
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eor x0, x0, x3 // Clear low bits
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mov x2, #1
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add x1, x1, x0, lsr #3 // Get word offset
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lsl x4, x2, x3 // Create mask
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smp_dmb ish
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1: ldxr x2, [x1]
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lsr x0, x2, x3 // Save old value of bit
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\instr x2, x2, x4 // toggle bit
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stxr w5, x2, [x1]
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cbnz w5, 1b
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smp_dmb ish
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and x0, x0, #1
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3: ret
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ENDPROC(\name )
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.endm
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/*
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* Atomic bit operations.
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*/
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bitop change_bit, eor
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bitop clear_bit, bic
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bitop set_bit, orr
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testop test_and_change_bit, eor
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testop test_and_clear_bit, bic
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testop test_and_set_bit, orr
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