forked from Minki/linux
b886d83c5b
Based on 1 normalized pattern(s): 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 version 2 of the license extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 315 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Armijn Hemel <armijn@tjaldur.nl> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190531190115.503150771@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
48 lines
993 B
ArmAsm
48 lines
993 B
ArmAsm
/* SPDX-License-Identifier: GPL-2.0-only */
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#include <linux/linkage.h>
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#include <asm/percpu.h>
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.text
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/*
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* Inputs:
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* %rsi : memory location to compare
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* %rax : low 64 bits of old value
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* %rdx : high 64 bits of old value
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* %rbx : low 64 bits of new value
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* %rcx : high 64 bits of new value
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* %al : Operation successful
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*/
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ENTRY(this_cpu_cmpxchg16b_emu)
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#
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# Emulate 'cmpxchg16b %gs:(%rsi)' except we return the result in %al not
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# via the ZF. Caller will access %al to get result.
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#
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# Note that this is only useful for a cpuops operation. Meaning that we
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# do *not* have a fully atomic operation but just an operation that is
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# *atomic* on a single cpu (as provided by the this_cpu_xx class of
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# macros).
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#
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pushfq
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cli
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cmpq PER_CPU_VAR((%rsi)), %rax
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jne .Lnot_same
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cmpq PER_CPU_VAR(8(%rsi)), %rdx
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jne .Lnot_same
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movq %rbx, PER_CPU_VAR((%rsi))
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movq %rcx, PER_CPU_VAR(8(%rsi))
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popfq
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mov $1, %al
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ret
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.Lnot_same:
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popfq
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xor %al,%al
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ret
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ENDPROC(this_cpu_cmpxchg16b_emu)
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