MFHead @r350386

Sponsored by: The FreeBSD Foundation

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

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

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MFHead @347527

Sponsored by: The FreeBSD Foundation

ld-elf.so: make LD_DEBUG always functional.

This causes some increase of the dynamic linker size, but benefits of
avoiding compiling private copy or the linker when debugging is
required. definitely

ld-elf.so: make LD_DEBUG always functional.

This causes some increase of the dynamic linker size, but benefits of
avoiding compiling private copy or the linker when debugging is
required. definitely worth it.

The dbg() calls can be compiled out by defining LD_NO_DEBUG symbol.

Sponsored by: The FreeBSD Foundation
MFC after: 1 week

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MFHead@r345677

revert r341429 "disable BIND_NOW in libc, libthr, and rtld"

r345620 by kib@ fixed the rtld issue that caused a crash at startup
during resolution of libc's ifuncs with BIND_NOW.

PR: 233333
Sponsor

revert r341429 "disable BIND_NOW in libc, libthr, and rtld"

r345620 by kib@ fixed the rtld issue that caused a crash at startup
during resolution of libc's ifuncs with BIND_NOW.

PR: 233333
Sponsored by: The FreeBSD Foundation

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Merge ^/head r344178 through r344512.

MFhead@r344270

Add WITH_PIE knob to build Position Independent Executables

Building binaries as PIE allows the executable itself to be loaded at a
random address when ASLR is enabled (not just its shared libraries

Add WITH_PIE knob to build Position Independent Executables

Building binaries as PIE allows the executable itself to be loaded at a
random address when ASLR is enabled (not just its shared libraries).

With this change PIE objects have a .pieo extension and INTERNALLIB
libraries libXXX_pie.a.

MK_PIE is disabled for some kerberos5 tools, Clang, and Subversion, as
they explicitly reference .a libraries in their Makefiles. These can
be addressed on an individual basis later. MK_PIE is also disabled for
rtld-elf because it is already position-independent using bespoke
Makefile rules.

Currently only dynamically linked binaries will be built as PIE.

Discussed with: dim
Reviewed by: kib
MFC after: 1 month
Relnotes: Yes
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D18423

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Merge ^/head r343571 through r343711.

Rename rtld-elf/malloc.c to rtld-elf/rtld_malloc.c.

Then malloc.c file name is too generic to use it for libthr.a.

Sponsored by: The FreeBSD Foundation
MFC after: 13 days

Merge ^/head r340918 through r341763.

disable BIND_NOW in libc, libthr, and rtld

An issue remains with BIND_NOW and processes using threads. For now,
restore libc's BIND_NOW disable, and also disable BIND_NOW in rtld and
libthr.

A pat

disable BIND_NOW in libc, libthr, and rtld

An issue remains with BIND_NOW and processes using threads. For now,
restore libc's BIND_NOW disable, and also disable BIND_NOW in rtld and
libthr.

A patch is in review (D18400) that likely fixes this issue, but just
disable BIND_NOW pending further testing after it is committed.

PR: 233333
Sponsored by: The FreeBSD Foundation

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Revert r340843 - addressed independently in r340842!

rtld: Silence a false positive GCC 6.4.0 warning

The function reloc_non_plt has complicated variable lifetimes that GCC 6.4.0
(the version currently used by amd64-xtoolchain-gcc) misunderstands and

rtld: Silence a false positive GCC 6.4.0 warning

The function reloc_non_plt has complicated variable lifetimes that GCC 6.4.0
(the version currently used by amd64-xtoolchain-gcc) misunderstands and
produces an erroneous warning about. Silence it to allow the -Werror build
to proceed.

Reviewed by: emaste

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Merge ^/head r339813 through r340125.

rtld-elf: fix more warnings to allow compiling with WARNS=6

Reviewed By: kib
Approved By: brooks (mentor)
Differential Revision: https://reviews.freebsd.org/D17154

rtld-elf: compile with WANRS=4 warnings other than -Wcast-align

Reviewed By: kib
Approved By: brooks (mentor)
Differential Revision: https://reviews.freebsd.org/D17153

MFH r338661 through r339200.

Sponsored by: The FreeBSD Foundation

Merge ^/head r338731 through r338987.

Move libmap.conf to libexec/rtld-elf/

This leverages CONFS to handle the config file install.

Approved by: re (gjb), will (mentor)
Differential Revision: https://reviews.freebsd.org/D17161

Make rtld use libc_nossp_pic.a. Remove SSP shims.

Submitted by: Luis Pires
Reviewed by: brooks
Differential revision: https://reviews.freebsd.org/D15341

MFH @ r323558.

MFhead@r323343

Compile reloc.o with -fno-jump-tables on MIPS.

In particular, the switch statement on the type of dynamic entries
in _rtld_relocate_nonplt_self() needs to not use a jump table since
jump tables on M

Compile reloc.o with -fno-jump-tables on MIPS.

In particular, the switch statement on the type of dynamic entries
in _rtld_relocate_nonplt_self() needs to not use a jump table since
jump tables on MIPS use local GOT entries which aren't initialized
until after this loop.

Suggested by: arichardson
Reviewed by: emaste
Sponsored by: DARPA / AFRL

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