delta/glibc.git/elf/Makefile, branch maskray/relr

elf: Support DT_RELR relative relocation format [BZ #27924]

2022-03-09T01:17:05+00:00

PIE and shared objects usually have many relative relocations. In
2017/2018, SHT_RELR/DT_RELR was proposed on
https://groups.google.com/g/generic-abi/c/bX460iggiKg/m/GxjM0L-PBAAJ
("Proposal for a new section type SHT_RELR") and is a pre-standard. RELR
usually takes 3% or smaller space than R_*_RELATIVE relocations. The
virtual memory size of a mostly statically linked PIE is typically 5~10%
smaller.

This patch adds ELF_DYNAMIC_DO_RELR to ELF_DYNAMIC_RELOCATE.
ELF_DYNAMIC_DO_RELR is ordered before ELF_DYNAMIC_DO_REL[A] so that ifunc
resolvers that require relocated got entries have them relocated. This is
needed for ppc64 according to Alan Modra.

Linux: Consolidate auxiliary vector parsing (redo)

2022-02-28T10:50:41+00:00

And optimize it slightly.

This is commit 8c8510ab2790039e58995ef3a22309582413d3ff revised.

In _dl_aux_init in elf/dl-support.c, use an explicit loop
and -fno-tree-loop-distribute-patterns to avoid memset.

Reviewed-by: Szabolcs Nagy

build: Properly generate .d dependency files [BZ #28922]

2022-02-25T18:35:45+00:00

1. Also generate .d dependency files for $(tests-container) and
$(tests-printers).
2. elf: Add tst-auditmod17.os to extra-test-objs.
3. iconv: Add tst-gconv-init-failure-mod.os to extra-test-objs.
4. malloc: Rename extra-tests-objs to extra-test-objs.
5. linux: Add tst-sysconf-iov_max-uapi.o to extra-test-objs.
6. x86_64: Add tst-x86_64mod-1.o, tst-platformmod-2.o, test-libmvec.o,
test-libmvec-avx.o, test-libmvec-avx2.o and test-libmvec-avx512f.o to
extra-test-objs.
Reviewed-by: Carlos O'Donell

elf: Remove prelink support

2022-02-10T12:16:12+00:00

Prelinked binaries and libraries still work, the dynamic tags
DT_GNU_PRELINKED, DT_GNU_LIBLIST, DT_GNU_CONFLICT just ignored
(meaning the process is reallocated as default).

The loader environment variable TRACE_PRELINKING is also removed,
since it used solely on prelink.

Checked on x86_64-linux-gnu, i686-linux-gnu, and aarch64-linux-gnu.

Reviewed-by: Siddhesh Poyarekar

hppa: Fix bind-now audit (BZ #28857)

2022-02-09T11:47:42+00:00

On hppa, a function pointer returned by la_symbind is actually a function
descriptor has the plabel bit set (bit 30).  This must be cleared to get
the actual address of the descriptor.  If the descriptor has been bound,
the first word of the descriptor is the physical address of theA function,
otherwise, the first word of the descriptor points to a trampoline in the
PLT.

This patch also adds a workaround on tests because on hppa (and it seems
to be the only ABI I have see it), some shared library adds a dynamic PLT
relocation to am empty symbol name:

$ readelf -r elf/tst-audit25mod1.so
[...]
Relocation section '.rela.plt' at offset 0x464 contains 6 entries:
 Offset     Info    Type            Sym.Value  Sym. Name + Addend
00002008  00000081 R_PARISC_IPLT                508
[...]

It breaks some assumptions on the test, where a symbol with an empty
name ("") is passed on la_symbind.

Checked on x86_64-linux-gnu and hppa-linux-gnu.

elf: Replace tst-audit24bmod2.so with tst-audit24bmod2

2022-02-06T19:12:24+00:00

Replace tst-audit24bmod2.so with tst-audit24bmod2 to silence:

make[2]: Entering directory '/export/gnu/import/git/gitlab/x86-glibc/elf'
Makefile:2201: warning: overriding recipe for target '/export/build/gnu/tools-build/glibc-gitlab/build-x86_64-linux/elf/tst-audit24bmod2.so'
../Makerules:765: warning: ignoring old recipe for target '/export/build/gnu/tools-build/glibc-gitlab/build-x86_64-linux/elf/tst-audit24bmod2.so'

Fix elf/tst-audit25a with default bind now toolchains

2022-02-02T14:03:58+00:00

This test relies on lazy binding for the executable so request that
explicitly in case the toolchain defaults to bind now.

elf: Issue la_symbind for bind-now (BZ #23734)

2022-02-01T17:49:46+00:00

The audit symbind callback is not called for binaries built with
-Wl,-z,now or when LD_BIND_NOW=1 is used, nor the PLT tracking callbacks
(plt_enter and plt_exit) since this would change the expected
program semantics (where no PLT is expected) and would have performance
implications (such as for BZ#15533).

LAV_CURRENT is also bumped to indicate the audit ABI change (where
la_symbind flags are set by the loader to indicate no possible PLT
trace).

To handle powerpc64 ELFv1 function descriptor, _dl_audit_symbind
requires to know whether bind-now is used so the symbol value is
updated to function text segment instead of the OPD (for lazy binding
this is done by PPC64_LOAD_FUNCPTR on _dl_runtime_resolve).

Checked on x86_64-linux-gnu, i686-linux-gnu, aarch64-linux-gnu,
powerpc64-linux-gnu.

Reviewed-by: Carlos O'Donell 
Tested-by: Carlos O'Donell

elf: Fix initial-exec TLS access on audit modules (BZ #28096)

2022-02-01T17:49:46+00:00

For audit modules and dependencies with initial-exec TLS, we can not
set the initial TLS image on default loader initialization because it
would already be set by the audit setup.  However, subsequent thread
creation would need to follow the default behaviour.

This patch fixes it by setting l_auditing link_map field not only
for the audit modules, but also for all its dependencies.  This is
used on _dl_allocate_tls_init to avoid the static TLS initialization
at load time.

Checked on x86_64-linux-gnu, i686-linux-gnu, and aarch64-linux-gnu.

Reviewed-by: Carlos O'Donell 
Tested-by: Carlos O'Donell

elf: Add la_activity during application exit

2022-02-01T17:49:46+00:00

la_activity is not called during application exit, even though
la_objclose is.

Checked on x86_64-linux-gnu, i686-linux-gnu, and aarch64-linux-gnu.

Reviewed-by: Carlos O'Donell 
Tested-by: Carlos O'Donell