8d77cd5069
They originated in the original Octeon port. They weren't present, as far as I can tell, on the projects/mips branch until after this point. They were in the original Octeon port in code picked up from the vendor, who I've been able to find out trolling old email put them there to get around an SMP problem that most likely was fixed in other ways. NetBSD and Linux don't have these, except for some specific uses of SYNC on the alchemy parts (which we don't support, but even if we did it is only a specific case and would be specifically coded anyway). This is true of the current Linux code, as well as one old version I polled. I looked back at the old R12000, R8000, R6000, R4000, R4400 errata that I have, and could find no mention of SYNC needing NOPs for silicon bugs (although plenty of other cases where NOPs and other contortions were needed). An Google search turned up no old mailing list discussions on this on Linux, NetBSD or FreeBSD (except the disussion that kicked off these studies). I've test booted this on my Octeon Plus eval board and survived a buildworld. Adrian Chadd reports that this patch has no ill effects on the Ahteros platforms he tested it on. I conclude it is safe to just remove the NOPs. But added __MIPS_PLATFORM_SYNC_NOPS as a failsafe in case we find some platform where these are, in fact, required. Reviewed by: adrian@
This is the top level of the FreeBSD source directory. This file was last revised on: $FreeBSD$ For copyright information, please see the file COPYRIGHT in this directory (additional copyright information also exists for some sources in this tree - please see the specific source directories for more information). The Makefile in this directory supports a number of targets for building components (or all) of the FreeBSD source tree, the most commonly used one being ``world'', which rebuilds and installs everything in the FreeBSD system from the source tree except the kernel, the kernel-modules and the contents of /etc. The ``world'' target should only be used in cases where the source tree has not changed from the currently running version. See: http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/makeworld.html for more information, including setting make(1) variables. The ``buildkernel'' and ``installkernel'' targets build and install the kernel and the modules (see below). Please see the top of the Makefile in this directory for more information on the standard build targets and compile-time flags. Building a kernel is a somewhat more involved process, documentation for which can be found at: http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/kernelconfig.html And in the config(8) man page. Note: If you want to build and install the kernel with the ``buildkernel'' and ``installkernel'' targets, you might need to build world before. More information is available in the handbook. The sample kernel configuration files reside in the sys/<arch>/conf sub-directory (assuming that you've installed the kernel sources), the file named GENERIC being the one used to build your initial installation kernel. The file NOTES contains entries and documentation for all possible devices, not just those commonly used. It is the successor of the ancient LINT file, but in contrast to LINT, it is not buildable as a kernel but a pure reference and documentation file. Source Roadmap: --------------- bin System/user commands. cddl Various commands and libraries under the Common Development and Distribution License. contrib Packages contributed by 3rd parties. crypto Cryptography stuff (see crypto/README). etc Template files for /etc. games Amusements. gnu Various commands and libraries under the GNU Public License. Please see gnu/COPYING* for more information. include System include files. kerberos5 Kerberos5 (Heimdal) package. lib System libraries. libexec System daemons. release Release building Makefile & associated tools. rescue Build system for statically linked /rescue utilities. sbin System commands. secure Cryptographic libraries and commands. share Shared resources. sys Kernel sources. tools Utilities for regression testing and miscellaneous tasks. usr.bin User commands. usr.sbin System administration commands. For information on synchronizing your source tree with one or more of the FreeBSD Project's development branches, please see: http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/synching.html