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Alex Richardson b54a59f3ba Reduce size of rtld by 22% by pulling in less code from libc
Currently RTLD is linked against libc_nossp_pic which means that any libc
symbol used in rtld can pull in a lot of depedencies. This was causing
symbol such as __libc_interposing and all the pthread stubs to be included
in RTLD even though they are not required. It turns out most of these
dependencies can easily be avoided by providing overrides inside of rtld.

This change is motivated by CHERI, where we have an experimental ABI that
requires additional relocation processing to allow the use of function
pointers inside of rtld. Instead of adding this self-relocation code to
RTLD I attempted to remove most function pointers from RTLD and discovered
that most of them came from the libc dependencies instead of being actually
used inside rtld.

A nice side-effect of this change is that rtld is now 22% smaller on amd64.

   text	   data	    bss	    dec	    hex	filename
0x21eb6	  0xce0	  0xe60	 145910	  239f6	/home/alr48/ld-elf-x86.before.so.1
0x1a6ed	  0x728	  0xdd8	 113645	  1bbed	/home/alr48/ld-elf-x86.after.so.1

The number of R_X86_64_RELATIVE relocations that need to be processed on
startup has also gone down from 368 to 187 (almost 50% less).

Reviewed By:	kib
Differential Revision: https://reviews.freebsd.org/D20663
2019-06-30 11:49:58 +00:00
bin Fix .depend files to work for build tools. 2019-06-15 17:08:13 +00:00
cddl DTrace: add a top level makefile to the new test suit 2019-06-09 22:45:07 +00:00
contrib MFV r349535: less v551. 2019-06-29 18:41:40 +00:00
crypto Complete LOCAL_PEERCRED support. Cache pid of the remote process in the 2019-05-30 14:24:26 +00:00
etc Remove NAND and NANDFS support 2019-06-25 04:50:09 +00:00
gnu powerpc: Transition to Secure-PLT, like most other OSs (Toolchain part) 2019-06-25 02:35:22 +00:00
include Remove NAND and NANDFS support 2019-06-25 04:50:09 +00:00
kerberos5 Add WITH_PIE knob to build Position Independent Executables 2019-02-15 22:22:38 +00:00
lib Reduce size of rtld by 22% by pulling in less code from libc 2019-06-30 11:49:58 +00:00
libexec Reduce size of rtld by 22% by pulling in less code from libc 2019-06-30 11:49:58 +00:00
release picobsd: also exclude .git where we exclude .svn today 2019-06-27 13:31:55 +00:00
rescue rescue: set NO_SHARED in Makefile 2018-11-19 22:18:18 +00:00
sbin Add an external mbuf buffer type that holds multiple unmapped pages. 2019-06-29 00:48:33 +00:00
secure Merge OpenSSL 1.1.1c. 2019-05-28 21:54:12 +00:00
share Fix VOP_PUTPAGES(9) in regards to the use of VM_PAGER_CLUSTER_OK 2019-06-29 14:55:53 +00:00
stand Increase EFI_STAGING_SIZE to 100MB on x64 2019-06-27 22:06:41 +00:00
sys Display the approximate space needed when a minidump fails due to lack 2019-06-30 03:14:04 +00:00
targets Remove NAND and NANDFS support 2019-06-25 04:50:09 +00:00
tests Skip sys.netpfil.pf.names.names and sys.netpfil.pf.synproxy.synproxy 2019-06-29 12:19:57 +00:00
tools Add support for Python 3 and make it the default. 2019-06-30 02:29:12 +00:00
usr.bin MFV r349535: less v551. 2019-06-29 18:41:40 +00:00
usr.sbin Use __FBSDID() and sort #includes. 2019-06-27 21:45:40 +00:00
.arcconfig callsign isn't required anymore 2016-09-29 06:19:45 +00:00
.arclint arc lint: ignore /tests/ in chmod 2017-12-19 03:38:06 +00:00
.cirrus.yml Cirrus-CI: pass OVMF env var to test script for upcoming changes 2019-04-11 13:01:26 +00:00
.clang-format Add a basic clang-format configuration file 2019-06-07 15:23:52 +00:00
.gitattributes Add a basic clang-format configuration file 2019-06-07 15:23:52 +00:00
.gitignore Ignore _.universe-toolchain file. 2018-07-01 13:50:37 +00:00
COPYRIGHT Happy New Year 2019! 2019-01-01 00:25:25 +00:00
LOCKS LOCKS: update current locks 2018-06-09 03:08:04 +00:00
MAINTAINERS Update/reformat maintainer entries that I am a part of 2019-04-29 18:48:43 +00:00
Makefile Modernize the MAKE_JUST_KERNELS hint in the top-level makefile. 2019-05-24 15:45:43 +00:00
Makefile.inc1 Add head(1) to native-xtools so that it can be used in qemu-user jails 2019-06-20 13:24:58 +00:00
Makefile.libcompat Build lib32 libl. The library is built from usr.bin/lex/lib. It would be 2019-06-29 17:01:56 +00:00
Makefile.sys.inc AUTO_OBJ: For all top-level targets enforce using an OBJDIR. 2017-12-05 21:29:47 +00:00
ObsoleteFiles.inc Remove sys/capability.h for the third time 2019-06-18 14:13:52 +00:00
README Vendor import of less v551. 2019-06-29 04:39:01 +00:00
README.md README: add generic notes about GENERIC and NOTES 2018-06-17 19:44:24 +00:00
UPDATING Fixup UPDATING text for r349253 2019-06-21 00:33:45 +00:00

FreeBSD Source:

This is the top level of the FreeBSD source directory. This file was last revised on: FreeBSD

FreeBSD is an operating system used to power modern servers, desktops, and embedded platforms. A large community has continually developed it for more than thirty years. Its advanced networking, security, and storage features have made FreeBSD the platform of choice for many of the busiest web sites and most pervasive embedded networking and storage devices.

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), config(8), https://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/makeworld.html, and https://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/kernelconfig.html for more information, including setting make(1) variables.

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.

stand		Boot loader sources.

sys		Kernel sources.

sys/<arch>/conf Kernel configuration files. GENERIC is the configuration
		used in release builds. NOTES contains documentation of
		all possible entries.

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:

https://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/current-stable.html