3fd63ddfdf
In some cases the DELAY implementation on amd64 can recurse on a spin mutex in the i8254 early delay code. Detect when this is going to happen and don't call delay in this case. It is safe to not delay here with the only issue being KCSAN may not detect data races. Reviewed by: kib Tested by: arichardson Sponsored by: Innovate UK Differential Revision: https://reviews.freebsd.org/D28895
84 lines
2.3 KiB
C
84 lines
2.3 KiB
C
/* $NetBSD: csan.h,v 1.2 2019/11/06 06:57:22 maxv Exp $ */
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/*
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* Copyright (c) 2019 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Maxime Villard.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#include <sys/timetc.h>
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#include <machine/clock.h>
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#include <machine/cpufunc.h>
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#include <machine/stack.h>
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#include <machine/vmparam.h>
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static inline bool
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kcsan_md_unsupported(vm_offset_t addr)
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{
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return false;
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}
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static inline bool
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kcsan_md_is_avail(void)
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{
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return true;
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}
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static inline void
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kcsan_md_disable_intrs(uint64_t *state)
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{
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*state = intr_disable();
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}
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static inline void
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kcsan_md_enable_intrs(uint64_t *state)
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{
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intr_restore(*state);
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}
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static inline void
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kcsan_md_delay(uint64_t us)
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{
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/*
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* Only call DELAY if not using the early delay code. The i8254
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* early delay function may cause us to recurse on a spin lock
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* leading to a panic.
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*/
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if ((tsc_is_invariant && tsc_freq != 0) ||
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timecounter->tc_quality > 0)
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DELAY(us);
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}
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static void
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kcsan_md_unwind(void)
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{
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}
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