Find a file
Konstantin Belousov a3c8e04ef7 Currently, when mapping an object, rtld reserves the whole address space
for the mapping by the object' file with the protection and mode of
the first loadable segment over the whole region. Then, it maps other
segments at the appropriate addresses inside the region.

On amd64, due to default alignment of the segments being 1Gb, the
subsequent segment mappings leave the holes in the region, that usually
contain mapping of the object' file past eof. Such mappings prevent
wiring of the address space, because the pages cannot be faulted in.

Change the way the mapping of the ELF objects is constructed, by first
mapping PROT_NONE anonymous memory over the whole range, and then
mapping the segments of the object over it. Take advantage of this new
order and allocate .bss by changing the protection of the range instead
of remapping.

Note that we cannot simply keep the holes between segments, because
other mappings may be made there. Among other issues, when the dso is
unloaded, rtld unmaps the whole region, deleting unrelated mappings.

The kernel ELF image activator does put the holes between segments, but
this is not critical for now because kernel loads only executable image
and interpreter, both cannot be unloaded. This will be fixed later, if
needed.

Reported and tested by:	Hans Ottevanger <fbsdhackers beasties demon nl>
Suggested and reviewed by:	kan, alc
2009-04-10 10:14:04 +00:00
bin Don't let trailing empty lines overwrite the result of the last command with 0. 2009-04-04 19:06:52 +00:00
cddl Switch over to gnu99 compilation on default for userland. 2009-03-14 17:55:16 +00:00
contrib - Use gdb-* glob instead of gdb-6.1.1, to simplify future imports. 2009-04-07 20:15:51 +00:00
crypto Prevent cross-site forgery attacks on lukemftpd(8) due to splitting 2009-01-07 20:17:55 +00:00
etc - Add ipfw_nat to the list of required modules if "firewall_nat_enable" 2009-03-30 21:31:52 +00:00
games Too good to pass. 2009-03-06 13:24:54 +00:00
gnu Fix build breakage due to the interplay between r189801 and r189824. 2009-03-14 22:50:03 +00:00
include Implement support for RTLD_NODELETE flag for dlopen() and -z nodelete 2009-03-30 08:47:28 +00:00
kerberos5 Add strndup(3) prototype to string.h. 2008-12-08 21:04:24 +00:00
lib Include a space between "send" and "broadcast". 2009-04-09 20:57:35 +00:00
libexec Currently, when mapping an object, rtld reserves the whole address space 2009-04-10 10:14:04 +00:00
release Autogenerate hardware notes for the uath(4) driver. 2009-04-07 20:12:15 +00:00
rescue Remove if_ppp(4) and if_sl(4). 2009-04-05 22:08:18 +00:00
sbin - Implement the grow command to make it easier for users to extend plexes 2009-04-10 10:12:09 +00:00
secure Enable getaudit_addr(2) for sshd again. This will un-break the subject 2008-11-30 15:35:24 +00:00
share Add C++ operators to operator(7) manual page. 2009-04-08 20:20:19 +00:00
sys - Move out allocation part of different gvinum objects into its own routine and 2009-04-10 08:50:14 +00:00
tools Return -1 instead of 0 upon reaching EOF. This is somewhat ill-advised 2009-04-06 13:50:04 +00:00
usr.bin Avoid infinite loops when remaking makefiles not only 2009-04-07 19:49:38 +00:00
usr.sbin Removed more vestiges of if_sl(4). 2009-04-09 12:20:37 +00:00
COPYRIGHT Bump the odometer of the years. A little early this year for 7.1R. 2008-12-30 04:46:25 +00:00
LOCKS Update LOCKS syntax. 2008-06-05 19:47:58 +00:00
MAINTAINERS Replace anholt with myself as drm maintainer. 2009-03-20 18:51:13 +00:00
Makefile Add a new world named 'mips' to our universe. 2009-04-01 17:11:50 +00:00
Makefile.inc1 Revert c190007 at the request of Ruslan. It was not correct because 2009-04-05 00:24:49 +00:00
ObsoleteFiles.inc Removed more vestiges of if_sl(4). 2009-04-09 12:20:37 +00:00
README Simply running ``make world'' will bomb unless you dig up the 2006-06-07 03:33:48 +00:00
UPDATING A belated note on layout change of certain V_ containers. 2009-04-08 18:30:42 +00:00

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.

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