53f40ddc8e
it in emergency in sc_cnputc(). Locking fixes in sc_cnputc() previously turned off normal output in near-deadlock conditions and added deferred output which might never be completed. Emergency output goes to the frame buffer using sufficiently atomic non-blocking writes if the console is in text mode (in graphics mode, nothing is done, modulo races setting the graphics mode bit). Screen updates overwrite the emergency output if the emergency condition clears enough to reach them. ec_putc() also works for "early" console output in normal x86 text mode as soon as this mode is initialized (if ever). This uses a hard-coded x86 frame buffer address before cninit() and a hopefully MI address after cninit(). But non-x86 is more likely to not support text mode, when ec_putc() will be null. ec_putc() has no dependencies of syscons before cninit(), and only has them later to track syscons' mode changes. This commit doesn't attach ec_putc() for early use. To test emergency use, put a breakpoint in central syscons output code like sc_puts() and do some user output. The system used to race or deadlock in ddb output soon after entry to ddb. The locking fixes deferred the output until after leaving ddb, so ddb was unusable and you had to try typing c[ontinue] blindly until it exited, or better use a serial console in parallel. Now the output goes to a window in the middle 2/3 of the screen. Scrolling is circular and there is no cursor, but otherwise ec_putc() provides full dumb terminal functionality and very fast output that hides artificates from dumb overwrites. |
||
|---|---|---|
| bin | ||
| cddl | ||
| contrib | ||
| crypto | ||
| etc | ||
| gnu | ||
| include | ||
| kerberos5 | ||
| lib | ||
| libexec | ||
| release | ||
| rescue | ||
| sbin | ||
| secure | ||
| share | ||
| sys | ||
| targets | ||
| tests | ||
| tools | ||
| usr.bin | ||
| usr.sbin | ||
| .arcconfig | ||
| .arclint | ||
| COPYRIGHT | ||
| LOCKS | ||
| MAINTAINERS | ||
| Makefile | ||
| Makefile.inc1 | ||
| Makefile.libcompat | ||
| ObsoleteFiles.inc | ||
| README | ||
| README.md | ||
| UPDATING | ||
FreeBSD Source:
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. See build(7) and 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. See build(7), config(8), and http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/kernelconfig.html for more information.
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 kernel configuration files reside in the sys/<arch>/conf
sub-directory. GENERIC is the default configuration used in release builds.
NOTES contains entries and documentation for all possible
devices, not just those commonly used.
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.
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.
tests Regression tests which can be run by Kyua. See tests/README
for additional information.
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