/* $NetBSD: membar_ops.S,v 1.13 2022/04/21 12:06:31 riastradh Exp $ */ /*- * Copyright (c) 2006, 2007 The NetBSD Foundation, Inc. * All rights reserved. * * This code is derived from software contributed to The NetBSD Foundation * by Jason R. Thorpe, and by Andrew Doran. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. */ #include "atomic_op_asm.h" .text .set noreorder LEAF(_membar_sync) j ra BDSYNC END(_membar_sync) ATOMIC_OP_ALIAS(membar_sync,_membar_sync) STRONG_ALIAS(_membar_enter,_membar_sync) ATOMIC_OP_ALIAS(membar_enter,_membar_sync) #ifdef __OCTEON__ /* * cnMIPS guarantees load-before-load/store ordering without any * barriers. So the only barriers we need are store-before-load (sync) * and store-before-store (syncw, i.e., sync 4). See Table 2-32 * `Execution Ordering Rules' on p. 104 of Cavium OCTEON III CN78XX * Hardware Reference Manual, CN78XX-HM-0.99E, September 2014: * * First Operation DLD [load instruction to a physical * address that is L2/DRAM] * Second Operation Any * Execution Ordering Comments * * The second operation cannot appear to execute before * the first (DLD) operation, regardless of the presence * or absence of SYNC* instructions. * * Note: I'm not sure if this applies to earlier cnMIPS -- can't find * it in the Cavium Networks OCTEON Plus CN50XX Hardware Reference * Manual CN50XX-HM-0.99E, July 2008. Experimentally, on an erlite3 * (Cavium Octeon CN5020-500), I can easily detect reordering of * store-before-store and store-before-load, but I haven't been able to * detect any reordering of load-before-load or load-before-store. * * Note: On early cnMIPS (CN3xxx), there is an erratum which sometimes * requires issuing two syncw's in a row. I don't know the details -- * don't have documentation -- and in Linux it is only used for I/O * purposes. * * Currently we don't build kernels that work on both Octeon and * non-Octeon MIPS CPUs, so none of this is done with binary patching. * For userlands we could use a separate shared library on Octeon with * ld.so.conf to override the symbols with cheaper definitions, but we * don't do that now. */ LEAF(_membar_acquire) j ra nop END(_membar_acquire) ATOMIC_OP_ALIAS(membar_acquire,_membar_acquire) STRONG_ALIAS(_membar_consumer,_membar_acquire) ATOMIC_OP_ALIAS(membar_consumer,_membar_acquire) LEAF(_membar_release) j ra syncw END(_membar_release) ATOMIC_OP_ALIAS(membar_release,_membar_release) STRONG_ALIAS(_membar_exit,_membar_release) ATOMIC_OP_ALIAS(membar_exit,_membar_release) STRONG_ALIAS(_membar_producer,_membar_release) ATOMIC_OP_ALIAS(membar_producer,_membar_release) #else /* !__OCTEON__ */ STRONG_ALIAS(_membar_acquire,_membar_sync) ATOMIC_OP_ALIAS(membar_acquire,_membar_sync) STRONG_ALIAS(_membar_release,_membar_sync) ATOMIC_OP_ALIAS(membar_release,_membar_sync) STRONG_ALIAS(_membar_exit,_membar_sync) ATOMIC_OP_ALIAS(membar_exit,_membar_sync) STRONG_ALIAS(_membar_consumer,_membar_sync) ATOMIC_OP_ALIAS(membar_consumer,_membar_sync) STRONG_ALIAS(_membar_producer,_membar_sync) ATOMIC_OP_ALIAS(membar_producer,_membar_sync) #endif