freebsd kernel with SKQ
bed16055e7
Dividing by 0 in order to check for irq13/exception16 delivery apparently always causes an irq13 even if we have configured for exception16 (by setting CR0_NE). This was expected, but the timing of the irq13 was unexpected. Without CR0_NE, the irq13 is delivered synchronously at least on my test machine, but with CR0_NE it is delivered a little later (about 250 nsec) in PIC mode and much later (5000-10000 nsec) in APIC mode. So especially in APIC mode, the irq13 may arrive after it is supposed to be shut down. It should then be masked, but the shutdown is incomplete, so the irq goes to a null handler that just reports it as stray. The fix is to wait a bit after dividing by 0 to give a good chance of the irq13 being handled by its proper handler. Removed the hack that was supposed to recover from the incomplete shutdown of irq13. The shutdown is now even more incomplete, or perhaps just incomplete in a different way, but the hack now has no effect because irq13 is edge triggered and handling of edge triggered interrupts is now optimized by skipping their masking. The hack only worked due to it accidentally not losing races. The incomplete shutdown of irq13 still allows unprivileged users to generate a stray irq13 (except on systems where irq13 is actually used) by unmasking an npx exception and causing one. The exception gets handled properly by the exception 16 handler. A spurious irq13 is delivered asynchronously but is harmless (as in the probe) because it is almost perfectly not handled by the null interrupt handler. Perfectly not handling it involves mainly not resetting the npx busy latch. This prevents further irq13's despite them not being masked in the [A]PIC. |
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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 | ||
| installworld_newk | ||
| installworld_oldk | ||
| MAINTAINERS | ||
| Makefile | ||
| Makefile.inc1 | ||
| README | ||
| UPDATING | ||
| UPDATING.64BTT | ||
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