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dda5f312bb
The sync_*() ops on arch/arm are defined in terms of the regular bitops
with no special handling. This is not correct, as UP kernels elide
barriers for the fully-ordered operations, and so the required ordering
is lost when such UP kernels are run under a hypervsior on an SMP
system.
Fix this by defining sync ops with the required barriers.
Note: On 32-bit arm, the sync_*() ops are currently only used by Xen,
which requires ARMv7, but the semantics can be implemented for ARMv6+.
Fixes: e54d2f6152 ("xen/arm: sync_bitops")
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20230605070124.3741859-2-mark.rutland@arm.com
17 lines
353 B
ArmAsm
17 lines
353 B
ArmAsm
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* linux/arch/arm/lib/testchangebit.S
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*
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* Copyright (C) 1995-1996 Russell King
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*/
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#include <linux/linkage.h>
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#include <asm/assembler.h>
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#include "bitops.h"
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.text
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testop _test_and_change_bit, eor, str
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#if __LINUX_ARM_ARCH__ >= 6
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sync_testop _sync_test_and_change_bit, eor, str
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#endif
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