freebsd kernel with SKQ
bc4334bd19
Quick fix for calling DELAY() for ddb input in some (atkbd-based) console drivers. ddb must not use any normal locks, but DELAY() normally calls getit() which needs clock_lock. One problem with using normal locks in ddb is that deadlock is possible, but deadlock on clock_lock is unlikely becaluse clock_lock is bogusly recursive, apparently just to hide the problem of ddb using it. The i8254 clock hardware has mostly write-only registers so it is important for it to use a lock that gives exclusive access. (atkbd hardware is also unfriendly to reentrant software but that problem is more local and already solved.) I mostly saw the symptoms of the bug caused by unlocking in getit() running cpu_unpend(). cpu_unpend() should not be called while in ddb and Debugger() calls for failing assertions about this caused a breakpoint within ddb. ddb must also not call getit() because ddb may be being used to step through clock initialization code that has stopped or otherwise mangled the clock. If the clock is stopped, then getit() always returns the same value and DELAY() takes forever if it trusts getit(). The quick fix is implement DELAY(n) as (n * timer_freq / 1000000) inb(0x84)'s if ddb is active. machdep.c: Don't permit recursion on clock_lock. |
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| bin | ||
| contrib | ||
| crypto | ||
| etc | ||
| games | ||
| gnu | ||
| include | ||
| kerberos5 | ||
| lib | ||
| libexec | ||
| release | ||
| rescue | ||
| sbin | ||
| secure | ||
| share | ||
| sys | ||
| tools | ||
| usr.bin | ||
| usr.sbin | ||
| COPYRIGHT | ||
| MAINTAINERS | ||
| Makefile | ||
| Makefile.inc1 | ||
| README | ||
| UPDATING | ||
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 ``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. 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. 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