Compiler generates the following instruction sequence for GNU2 dynamic
TLS access:
leaq tls_var@TLSDESC(%rip), %rax
call *tls_var@TLSCALL(%rax)
or
leal tls_var@TLSDESC(%ebx), %eax
call *tls_var@TLSCALL(%eax)
CALL instruction is transparent to compiler which assumes all registers,
except for EFLAGS and RAX/EAX, are unchanged after CALL. When
_dl_tlsdesc_dynamic is called, it calls __tls_get_addr on the slow
path. __tls_get_addr is a normal function which doesn't preserve any
caller-saved registers. _dl_tlsdesc_dynamic saved and restored integer
caller-saved registers, but didn't preserve any other caller-saved
registers. Add _dl_tlsdesc_dynamic IFUNC functions for FNSAVE, FXSAVE,
XSAVE and XSAVEC to save and restore all caller-saved registers. This
fixes BZ #31372.
Add GLRO(dl_x86_64_runtime_resolve) with GLRO(dl_x86_tlsdesc_dynamic)
to optimize elf_machine_runtime_setup.
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
1. Remove _dl_runtime_resolve_shstk and _dl_runtime_profile_shstk.
2. Move CET offsets from x86 cpu-features-offsets.sym to x86-64
features-offsets.sym.
3. Rename x86 cet-control.h to x86-64 feature-control.h since it is only
for x86-64 and also used for PLT rewrite.
4. Add x86-64 ldsodefs.h to include feature-control.h.
5. Change TUNABLE_CALLBACK (set_plt_rewrite) to x86-64 only.
6. Move x86 dl-procruntime.c to x86-64.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
The _dl_non_dynamic_init does not parse LD_PROFILE, which does not
enable profile for dlopen objects. Since dlopen is deprecated for
static objects, it is better to remove the support.
It also allows to trim down libc.a of profile support.
Checked on x86_64-linux-gnu.
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
If an executable has copy relocations for extern protected data, that
can only work if the library containing the definition is built with
assumptions (a) the compiler emits GOT-generating relocations (b) the
linker produces R_*_GLOB_DAT instead of R_*_RELATIVE. Otherwise the
library uses its own definition directly and the executable accesses a
stale copy. Note: the GOT relocations defeat the purpose of protected
visibility as an optimization, but allow rtld to make the executable and
library use the same copy when copy relocations are present, but it
turns out this never worked perfectly.
ELF_RTYPE_CLASS_EXTERN_PROTECTED_DATA has strange semantics when both
a.so and b.so define protected var and the executable copy relocates
var: b.so accesses its own copy even with GLOB_DAT. The behavior change
is from commit 62da1e3b00 (x86) and then
copied to nios2 (ae5eae7cfc) and arc
(0e7d930c4c).
Without ELF_RTYPE_CLASS_EXTERN_PROTECTED_DATA, b.so accesses the copy
relocated data like a.so.
There is now a warning for copy relocation on protected symbol since
commit 7374c02b68. It's extremely
unlikely anyone relies on the ELF_RTYPE_CLASS_EXTERN_PROTECTED_DATA
behavior, so let's remove it: this removes a check in the symbol lookup
code.
Since ad43cac44a the generic code already shuffles the argv/envp/auxv
on the stack to remove the ld.so own arguments and thus _dl_skip_args
is always 0. So there is no need to adjust the argc or argv.
Checked on i686-linux-gnu.
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
-z combreloc has been the default regadless of the architecture since
binutils commit f4d733664aabd7bd78c82895e030ec9779a92809 (2002). The
configure check added in commit fdde83499a (2001) has long been
unneeded.
We can therefore treat HAVE_Z_COMBRELOC as always 1 and delete dead code
paths in dl-machine.h files (many were copied from commit a711b01d34
and ee0cb67ec2).
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
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 <siddhesh@sourceware.org>
I used these shell commands:
../glibc/scripts/update-copyrights $PWD/../gnulib/build-aux/update-copyright
(cd ../glibc && git commit -am"[this commit message]")
and then ignored the output, which consisted lines saying "FOO: warning:
copyright statement not found" for each of 7061 files FOO.
I then removed trailing white space from math/tgmath.h,
support/tst-support-open-dev-null-range.c, and
sysdeps/x86_64/multiarch/strlen-vec.S, to work around the following
obscure pre-commit check failure diagnostics from Savannah. I don't
know why I run into these diagnostics whereas others evidently do not.
remote: *** 912-#endif
remote: *** 913:
remote: *** 914-
remote: *** error: lines with trailing whitespace found
...
remote: *** error: sysdeps/unix/sysv/linux/statx_cp.c: trailing lines
407765e9f2 ("hurd: Fix ELF_MACHINE_USER_ADDRESS_MASK value") switched
ELF_MACHINE_USER_ADDRESS_MASK from 0xf8000000UL to 0xf0000000UL to let
libraries etc. get loaded at 0x08000000. But
ELF_MACHINE_USER_ADDRESS_MASK is actually only meaningful for the main
program anyway, so keep it at 0xf8000000UL to prevent the program loader
from putting ld.so beyond 0x08000000. And conversely, drop the use of
ELF_MACHINE_USER_ADDRESS_MASK for shared objects, which don't need any
constraints since the program will have already be loaded by then.
It consolidates the code required to call la_pltexit audit
callback.
Checked on x86_64-linux-gnu, i686-linux-gnu, and aarch64-linux-gnu.
Reviewed-by: Florian Weimer <fweimer@redhat.com>
The 4af6982e4c fix does not fully handle RTLD_BOOTSTRAP usage on
rtld.c due two issues:
1. RTLD_BOOTSTRAP is also used on dl-machine.h on various
architectures and it changes the semantics of various machine
relocation functions.
2. The elf_get_dynamic_info() change was done sideways, previously
to 490e6c62aa get-dynamic-info.h was included by the first
dynamic-link.h include *without* RTLD_BOOTSTRAP being defined.
It means that the code within elf_get_dynamic_info() that uses
RTLD_BOOTSTRAP is in fact unused.
To fix 1. this patch now includes dynamic-link.h only once with
RTLD_BOOTSTRAP defined. The ELF_DYNAMIC_RELOCATE call will now have
the relocation fnctions with the expected semantics for the loader.
And to fix 2. part of 4af6982e4c is reverted (the check argument
elf_get_dynamic_info() is not required) and the RTLD_BOOTSTRAP
pieces are removed.
To reorganize the includes the static TLS definition is moved to
its own header to avoid a circular dependency (it is defined on
dynamic-link.h and dl-machine.h requires it at same time other
dynamic-link.h definition requires dl-machine.h defitions).
Also ELF_MACHINE_NO_REL, ELF_MACHINE_NO_RELA, and ELF_MACHINE_PLT_REL
are moved to its own header. Only ancient ABIs need special values
(arm, i386, and mips), so a generic one is used as default.
The powerpc Elf64_FuncDesc is also moved to its own header, since
csu code required its definition (which would require either include
elf/ folder or add a full path with elf/).
Checked on x86_64, i686, aarch64, armhf, powerpc64, powerpc32,
and powerpc64le.
Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
Before to 490e6c62aa ('elf: Avoid nested functions in the loader
[BZ #27220]'), elf_get_dynamic_info() was defined twice on rtld.c: on
the first dynamic-link.h include and later within _dl_start(). The
former definition did not define DONT_USE_BOOTSTRAP_MAP and it is used
on setup_vdso() (since it is a global definition), while the former does
define DONT_USE_BOOTSTRAP_MAP and it is used on loader self-relocation.
With the commit change, the function is now included and defined once
instead of defined as a nested function. So rtld.c defines without
defining RTLD_BOOTSTRAP and it brokes at least powerpc32.
This patch fixes by moving the get-dynamic-info.h include out of
dynamic-link.h, which then the caller can corirectly set the expected
semantic by defining STATIC_PIE_BOOTSTRAP, RTLD_BOOTSTRAP, and/or
RESOLVE_MAP.
It also required to enable some asserts only for the loader bootstrap
to avoid issues when called from setup_vdso().
As a side note, this is another issues with nested functions: it is
not clear from pre-processed output (-E -dD) how the function will
be build and its semantic (since nested function will be local and
extra C defines may change it).
I checked on x86_64-linux-gnu (w/o --enable-static-pie),
i686-linux-gnu, powerpc64-linux-gnu, powerpc-linux-gnu-power4,
aarch64-linux-gnu, arm-linux-gnu, sparc64-linux-gnu, and
s390x-linux-gnu.
Reviewed-by: Fangrui Song <maskray@google.com>
dynamic-link.h is included more than once in some elf/ files (rtld.c,
dl-conflict.c, dl-reloc.c, dl-reloc-static-pie.c) and uses GCC nested
functions. This harms readability and the nested functions usage
is the biggest obstacle prevents Clang build (Clang doesn't support GCC
nested functions).
The key idea for unnesting is to add extra parameters (struct link_map
*and struct r_scope_elm *[]) to RESOLVE_MAP,
ELF_MACHINE_BEFORE_RTLD_RELOC, ELF_DYNAMIC_RELOCATE, elf_machine_rel[a],
elf_machine_lazy_rel, and elf_machine_runtime_setup. (This is inspired
by Stan Shebs' ppc64/x86-64 implementation in the
google/grte/v5-2.27/master which uses mixed extra parameters and static
variables.)
Future simplification:
* If mips elf_machine_runtime_setup no longer needs RESOLVE_GOTSYM,
elf_machine_runtime_setup can drop the `scope` parameter.
* If TLSDESC no longer need to be in elf_machine_lazy_rel,
elf_machine_lazy_rel can drop the `scope` parameter.
Tested on aarch64, i386, x86-64, powerpc64le, powerpc64, powerpc32,
sparc64, sparcv9, s390x, s390, hppa, ia64, armhf, alpha, and mips64.
In addition, tested build-many-glibcs.py with {arc,csky,microblaze,nios2}-linux-gnu
and riscv64-linux-gnu-rv64imafdc-lp64d.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
This drops reliance on _GLOBAL_OFFSET_TABLE_[0] being the link-time
address of _DYNAMIC.
The code sequence length does not change.
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
Lazy tlsdesc relocation is racy because the static tls optimization and
tlsdesc management operations are done without holding the dlopen lock.
This similar to the commit b7cf203b5c
for aarch64, but it fixes a different race: bug 27137.
On i386 the code is a bit more complicated than on x86_64 because both
rel and rela relocs are supported.
Calling an IFUNC function defined in unrelocated executable also leads to
segfault. Issue a fatal error message when calling IFUNC function defined
in the unrelocated executable from a shared library.
I used these shell commands:
../glibc/scripts/update-copyrights $PWD/../gnulib/build-aux/update-copyright
(cd ../glibc && git commit -am"[this commit message]")
and then ignored the output, which consisted lines saying "FOO: warning:
copyright statement not found" for each of 6694 files FOO.
I then removed trailing white space from benchtests/bench-pthread-locks.c
and iconvdata/tst-iconv-big5-hkscs-to-2ucs4.c, to work around this
diagnostic from Savannah:
remote: *** pre-commit check failed ...
remote: *** error: lines with trailing whitespace found
remote: error: hook declined to update refs/heads/master
X86 CPU features in ld.so are initialized by init_cpu_features, which is
invoked by DL_PLATFORM_INIT from _dl_sysdep_start. But when ld.so is
loaded by static executable, DL_PLATFORM_INIT is never called. Also
x86 cache info in libc.o and libc.a is initialized by a constructor
which may be called too late. Since some fields in _rtld_global_ro
in ld.so are initialized by dynamic relocation, we can also initialize
x86 CPU features in _rtld_global_ro in ld.so and cache info in libc.so
by initializing dummy function pointers in ld.so and libc.so via IFUNC
relocation.
Key points:
1. IFUNC is always supported, independent of --enable-multi-arch or
--disable-multi-arch. Linker generates IFUNC relocations from input
IFUNC objects and ld.so performs IFUNC relocations.
2. There are no IFUNC dependencies in ld.so before dynamic relocation
have been performed,
3. The x86 CPU features in ld.so is initialized by DL_PLATFORM_INIT
in dynamic executable and by IFUNC relocation in dlopen in static
executable.
4. The x86 cache info in libc.o is initialized by IFUNC relocation.
5. In libc.a, both x86 CPU features and cache info are initialized from
ARCH_INIT_CPU_FEATURES, not by IFUNC relocation, before __libc_early_init
is called.
Note: _dl_x86_init_cpu_features can be called more than once from
DL_PLATFORM_INIT and during relocation in ld.so.
1. Include <dl-procruntime.c> to get architecture specific initializer in
rtld_global.
2. Change _dl_x86_feature_1[2] to _dl_x86_feature_1.
3. Add _dl_x86_feature_control after _dl_x86_feature_1, which is a
struct of 2 bitfields for IBT and SHSTK control
This fixes [BZ #25887].
This commit adds missing skip_ifunc checks to aarch64, arm, i386,
sparc, and x86_64. A new test case ensures that IRELATIVE IFUNC
resolvers do not run in various diagnostic modes of the dynamic
loader.
Reviewed-By: Szabolcs Nagy <szabolcs.nagy@arm.com>
This patch fixes -Wimplicit-fallthrough warnings in system-specific
code that show up building glibc with -Wextra, by adding fall-through
comments, or moving existing such comments to the place required for
them to work (immediately before the case label being fallen through).
Tested with build-many-glibcs.py.
* sysdeps/i386/dl-machine.h (elf_machine_rela): Add fall-through
comments.
* sysdeps/m68k/m680x0/fpu/s_cexp_template.c (s(__cexp)): Likewise.
* sysdeps/m68k/memcopy.h (WORD_COPY_FWD): Likewise.
(WORD_COPY_BWD): Likewise.
* sysdeps/mach/hurd/ioctl.c (__ioctl): Likewise.
* sysdeps/powerpc/powerpc64/dl-machine.h (elf_machine_rela):
Likewise.
* sysdeps/s390/iso-8859-1_cp037_z900.c (TR_LOOP): Likewise.
* sysdeps/mips/dl-machine.h (elf_machine_reloc): Move fall-through
comment.
* sysdeps/mips/dl-trampoline.c (__dl_runtime_resolve): Likewise.
When elf_machine_runtime_setup is called to set up resolver, it should
use _dl_runtime_resolve_shstk or _dl_runtime_profile_shstk if SHSTK is
enabled by kernel.
Tested on i686 with and without --enable-cet as well as on CET emulator
with --enable-cet.
[BZ #23716]
* sysdeps/i386/dl-cet.c: Removed.
* sysdeps/i386/dl-machine.h (_dl_runtime_resolve_shstk): New
prototype.
(_dl_runtime_profile_shstk): Likewise.
(elf_machine_runtime_setup): Use _dl_runtime_profile_shstk or
_dl_runtime_resolve_shstk if SHSTK is enabled by kernel.
Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
Wrap symbol address run-time calculation into a macro and use it
throughout, replacing inline calculations.
There are a couple of variants, most of them different in a functionally
insignificant way. Most calculations are right following RESOLVE_MAP,
at which point either the map or the symbol returned can be checked for
validity as the macro sets either both or neither. In some places both
the symbol and the map has to be checked however.
My initial implementation therefore always checked both, however that
resulted in code larger by as much as 0.3%, as many places know from
elsewhere that no check is needed. I have decided the size growth was
unacceptable.
Having looked closer I realized that it's the map that is the culprit.
Therefore I have modified LOOKUP_VALUE_ADDRESS to accept an additional
boolean argument telling it to access the map without checking it for
validity. This in turn has brought quite nice results, with new code
actually being smaller for i686, and MIPS o32, n32 and little-endian n64
targets, unchanged in size for x86-64 and, unusually, marginally larger
for big-endian MIPS n64, as follows:
i686:
text data bss dec hex filename
152255 4052 192 156499 26353 ld-2.27.9000-base.so
152159 4052 192 156403 262f3 ld-2.27.9000-elf-symbol-value.so
MIPS/o32/el:
text data bss dec hex filename
142906 4396 260 147562 2406a ld-2.27.9000-base.so
142890 4396 260 147546 2405a ld-2.27.9000-elf-symbol-value.so
MIPS/n32/el:
text data bss dec hex filename
142267 4404 260 146931 23df3 ld-2.27.9000-base.so
142171 4404 260 146835 23d93 ld-2.27.9000-elf-symbol-value.so
MIPS/n64/el:
text data bss dec hex filename
149835 7376 408 157619 267b3 ld-2.27.9000-base.so
149787 7376 408 157571 26783 ld-2.27.9000-elf-symbol-value.so
MIPS/o32/eb:
text data bss dec hex filename
142870 4396 260 147526 24046 ld-2.27.9000-base.so
142854 4396 260 147510 24036 ld-2.27.9000-elf-symbol-value.so
MIPS/n32/eb:
text data bss dec hex filename
142019 4404 260 146683 23cfb ld-2.27.9000-base.so
141923 4404 260 146587 23c9b ld-2.27.9000-elf-symbol-value.so
MIPS/n64/eb:
text data bss dec hex filename
149763 7376 408 157547 2676b ld-2.27.9000-base.so
149779 7376 408 157563 2677b ld-2.27.9000-elf-symbol-value.so
x86-64:
text data bss dec hex filename
148462 6452 400 155314 25eb2 ld-2.27.9000-base.so
148462 6452 400 155314 25eb2 ld-2.27.9000-elf-symbol-value.so
[BZ #19818]
* sysdeps/generic/ldsodefs.h (LOOKUP_VALUE_ADDRESS): Add `set'
parameter.
(SYMBOL_ADDRESS): New macro.
[!ELF_FUNCTION_PTR_IS_SPECIAL] (DL_SYMBOL_ADDRESS): Use
SYMBOL_ADDRESS for symbol address calculation.
* elf/dl-runtime.c (_dl_fixup): Likewise.
(_dl_profile_fixup): Likewise.
* elf/dl-symaddr.c (_dl_symbol_address): Likewise.
* elf/rtld.c (dl_main): Likewise.
* sysdeps/aarch64/dl-machine.h (elf_machine_rela): Likewise.
* sysdeps/alpha/dl-machine.h (elf_machine_rela): Likewise.
* sysdeps/arm/dl-machine.h (elf_machine_rel): Likewise.
(elf_machine_rela): Likewise.
* sysdeps/hppa/dl-machine.h (elf_machine_rela): Likewise.
* sysdeps/hppa/dl-symaddr.c (_dl_symbol_address): Likewise.
* sysdeps/i386/dl-machine.h (elf_machine_rel): Likewise.
(elf_machine_rela): Likewise.
* sysdeps/ia64/dl-machine.h (elf_machine_rela): Likewise.
* sysdeps/m68k/dl-machine.h (elf_machine_rela): Likewise.
* sysdeps/microblaze/dl-machine.h (elf_machine_rela): Likewise.
* sysdeps/mips/dl-machine.h (ELF_MACHINE_BEFORE_RTLD_RELOC):
Likewise.
(elf_machine_reloc): Likewise.
(elf_machine_got_rel): Likewise.
* sysdeps/mips/dl-trampoline.c (__dl_runtime_resolve): Likewise.
* sysdeps/nios2/dl-machine.h (elf_machine_rela): Likewise.
* sysdeps/powerpc/powerpc32/dl-machine.h (elf_machine_rela):
Likewise.
* sysdeps/powerpc/powerpc64/dl-machine.h (elf_machine_rela):
Likewise.
* sysdeps/riscv/dl-machine.h (elf_machine_rela): Likewise.
* sysdeps/s390/s390-32/dl-machine.h (elf_machine_rela):
Likewise.
* sysdeps/s390/s390-64/dl-machine.h (elf_machine_rela):
Likewise.
* sysdeps/sh/dl-machine.h (elf_machine_rela): Likewise.
* sysdeps/sparc/sparc32/dl-machine.h (elf_machine_rela):
Likewise.
* sysdeps/sparc/sparc64/dl-machine.h (elf_machine_rela):
Likewise.
* sysdeps/tile/dl-machine.h (elf_machine_rela): Likewise.
* sysdeps/x86_64/dl-machine.h (elf_machine_rela): Likewise.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
This code is used in non-PIE static executable and static PIE. It checks
if _DYNAMIC is undefined before using it to compute load address. But
not all targets can convert access _DYNAMIC via GOT, which needs dynamic
relocation, to PC-relative at link-time.
* sysdeps/i386/dl-machine.h (elf_machine_load_address): Don't
allow undefined _DYNAMIC in PIE libc.a.
* sysdeps/x86_64/dl-machine.h (elf_machine_load_address):
Likewse.
When --enable-static-pie is used to build static PIE, _DYNAMIC is used
to compute the load address of static PIE. But _DYNAMIC is undefined
when creating static executable. This patch makes _DYNAMIC weak in PIE
libc.a so that it can be undefined.
* sysdeps/i386/dl-machine.h (elf_machine_load_address): Allow
undefined _DYNAMIC in PIE libc.a.
* sysdeps/x86_64/dl-machine.h (elf_machine_load_address):
Likewse.
ELFv2 functions with localentry:0 are those with a single entry point,
ie. global entry == local entry, that have no requirement on r2 or
r12 and guarantee r2 is unchanged on return. Such an external
function can be called via the PLT without saving r2 or restoring it
on return, avoiding a common load-hit-store for small functions.
This patch implements the ld.so changes necessary for this
optimization. ld.so needs to check that an optimized plt call
sequence is in fact calling a function implemented with localentry:0,
end emit a fatal error otherwise.
The elf/testobj6.c change is to stop "error while loading shared
libraries: expected localentry:0 `preload'" when running
elf/preloadtest, which we'd get otherwise.
* elf/elf.h (PPC64_OPT_LOCALENTRY): Define.
* sysdeps/alpha/dl-machine.h (elf_machine_fixup_plt): Add
refsym and sym parameters. Adjust callers.
* sysdeps/aarch64/dl-machine.h (elf_machine_fixup_plt): Likewise.
* sysdeps/arm/dl-machine.h (elf_machine_fixup_plt): Likewise.
* sysdeps/generic/dl-machine.h (elf_machine_fixup_plt): Likewise.
* sysdeps/hppa/dl-machine.h (elf_machine_fixup_plt): Likewise.
* sysdeps/i386/dl-machine.h (elf_machine_fixup_plt): Likewise.
* sysdeps/ia64/dl-machine.h (elf_machine_fixup_plt): Likewise.
* sysdeps/m68k/dl-machine.h (elf_machine_fixup_plt): Likewise.
* sysdeps/microblaze/dl-machine.h (elf_machine_fixup_plt): Likewise.
* sysdeps/mips/dl-machine.h (elf_machine_fixup_plt): Likewise.
* sysdeps/nios2/dl-machine.h (elf_machine_fixup_plt): Likewise.
* sysdeps/powerpc/powerpc32/dl-machine.h (elf_machine_fixup_plt):
Likewise.
* sysdeps/s390/s390-32/dl-machine.h (elf_machine_fixup_plt): Likewise.
* sysdeps/s390/s390-64/dl-machine.h (elf_machine_fixup_plt): Likewise.
* sysdeps/sh/dl-machine.h (elf_machine_fixup_plt): Likewise.
* sysdeps/sparc/sparc32/dl-machine.h (elf_machine_fixup_plt): Likewise.
* sysdeps/sparc/sparc64/dl-machine.h (elf_machine_fixup_plt): Likewise.
* sysdeps/tile/dl-machine.h (elf_machine_fixup_plt): Likewise.
* sysdeps/x86_64/dl-machine.h (elf_machine_fixup_plt): Likewise.
* sysdeps/powerpc/powerpc64/dl-machine.c (_dl_error_localentry): New.
(_dl_reloc_overflow): Increase buffser size. Formatting.
* sysdeps/powerpc/powerpc64/dl-machine.h (ppc64_local_entry_offset):
Delete reloc param, add refsym and sym. Check optimized plt
call stubs for localentry:0 functions. Adjust callers.
(elf_machine_fixup_plt, elf_machine_plt_conflict): Add refsym
and sym parameters. Adjust callers.
(_dl_reloc_overflow): Move attribute.
(_dl_error_localentry): Declare.
* elf/dl-runtime.c (_dl_fixup): Save original sym. Pass
refsym and sym to elf_machine_fixup_plt.
* elf/testobj6.c (preload): Call printf.
dl_platform and dl_hwcap are set from AT_PLATFORM and AT_HWCAP very
early during startup. They are used by dynamic linker to determine
platform and build an array of hardware capability names, which are
added to search path when loading shared object. dl_platform and
dl_hwcap are unused on x86-64. On i386, i386, i486, i586 and i686
platforms were supported and only SSE2 capability was used.
On x86, usage of AT_PLATFORM and AT_HWCAP to determine platform and
processor capabilities is obsolete since all information is available
in dl_x86_cpu_features. This patch sets dl_platform and dl_hwcap from
dl_x86_cpu_features in dynamic linker. On i386, the available plaforms
are changed to i586 and i686 since i386 has been deprecated. On x86-64,
the available plaforms are haswell, which is for Haswell class processors
with BMI1, BMI2, LZCNT, MOVBE, POPCNT, AVX2 and FMA, and xeon_phi, which
is for Xeon Phi class processors with AVX512F, AVX512CD, AVX512ER and
AVX512PF. A capability, avx512_1, is also added to x86-64 for AVX512
ISAs: AVX512F, AVX512CD, AVX512BW, AVX512DQ and AVX512VL.
[BZ #21391]
* sysdeps/i386/dl-machine.h (dl_platform_init) [IS_IN (rtld)]:
Only call init_cpu_features.
[!IS_IN (rtld)]: Only set GLRO(dl_platform) to NULL if needed.
* sysdeps/x86_64/dl-machine.h (dl_platform_init): Likewise.
* sysdeps/i386/dl-procinfo.h: Removed.
* sysdeps/unix/sysv/linux/i386/dl-procinfo.h: Don't include
<sysdeps/i386/dl-procinfo.h> nor <ldsodefs.h>. Include
<sysdeps/x86/dl-procinfo.h>.
(_dl_procinfo): Replace _DL_HWCAP_COUNT with 32.
* sysdeps/unix/sysv/linux/x86_64/dl-procinfo.h [!IS_IN (ldconfig)]:
Include <sysdeps/x86/dl-procinfo.h> instead of
<sysdeps/generic/dl-procinfo.h>.
* sysdeps/x86/cpu-features.c: Include <dl-hwcap.h>.
(init_cpu_features): Set dl_platform, dl_hwcap and dl_hwcap_mask.
* sysdeps/x86/cpu-features.h (bit_cpu_LZCNT): New.
(bit_cpu_MOVBE): Likewise.
(bit_cpu_BMI1): Likewise.
(bit_cpu_BMI2): Likewise.
(index_cpu_BMI1): Likewise.
(index_cpu_BMI2): Likewise.
(index_cpu_LZCNT): Likewise.
(index_cpu_MOVBE): Likewise.
(index_cpu_POPCNT): Likewise.
(reg_BMI1): Likewise.
(reg_BMI2): Likewise.
(reg_LZCNT): Likewise.
(reg_MOVBE): Likewise.
(reg_POPCNT): Likewise.
* sysdeps/x86/dl-hwcap.h: New file.
* sysdeps/x86/dl-procinfo.h: Likewise.
* sysdeps/x86/dl-procinfo.c (_dl_x86_hwcap_flags): New.
(_dl_x86_platforms): Likewise.
IFUNC relocation against definition in unrelocated shared library
will lead to segfault when the IFUNC function is called. This
patch allows such IFUNC relocations with a warning. This isn't
a real fix for
https://sourceware.org/bugzilla/show_bug.cgi?id=21041
It simply allows the program to load. The program will segfault
when longjmp is called.
* sysdeps/i386/dl-machine.h (elf_machine_rel): Replace
_dl_fatal_printf with _dl_error_printf for IFUNC relocation
against unrelocated shared library.
* sysdeps/x86_64/dl-machine.h (elf_machine_rela): Likewise.
Calling an IFUNC function defined in unrelocated shared library may
lead to segfault. This patch issues an error message to request
relinking the shared library if it references IFUNC function defined
in the unrelocated shared library.
[BZ #20019]
* sysdeps/i386/dl-machine.h (elf_machine_rel): Check IFUNC
definition in unrelocated shared library.
* sysdeps/x86_64/dl-machine.h (elf_machine_rela): Likewise.
In static executable, since init_cpu_features is called early from
__libc_start_main, there is no need to call it again in dl_platform_init.
[BZ #20072]
* sysdeps/i386/dl-machine.h (dl_platform_init): Call
init_cpu_features only if SHARED is defined.
* sysdeps/x86_64/dl-machine.h (dl_platform_init): Likewise.
With copy relocation, address of protected data defined in the shared
library may be external. When there is a relocation against the
protected data symbol within the shared library, we need to check if we
should skip the definition in the executable copied from the protected
data. This patch adds ELF_RTYPE_CLASS_EXTERN_PROTECTED_DATA and defines
it for x86. If ELF_RTYPE_CLASS_EXTERN_PROTECTED_DATA isn't 0, do_lookup_x
will skip the data definition in the executable from copy reloc.
[BZ #17711]
* elf/dl-lookup.c (do_lookup_x): When UNDEF_MAP is NULL, which
indicates it is called from do_lookup_x on relocation against
protected data, skip the data definion in the executable from
copy reloc.
(_dl_lookup_symbol_x): Pass ELF_RTYPE_CLASS_EXTERN_PROTECTED_DATA,
instead of ELF_RTYPE_CLASS_PLT, to do_lookup_x for
EXTERN_PROTECTED_DATA relocation against STT_OBJECT symbol.
* sysdeps/generic/ldsodefs.h * (ELF_RTYPE_CLASS_EXTERN_PROTECTED_DATA):
New. Defined to 4 if DL_EXTERN_PROTECTED_DATA is defined,
otherwise to 0.
* sysdeps/i386/dl-lookupcfg.h (DL_EXTERN_PROTECTED_DATA): New.
* sysdeps/i386/dl-machine.h (elf_machine_type_class): Set class
to ELF_RTYPE_CLASS_EXTERN_PROTECTED_DATA for R_386_GLOB_DAT.
* sysdeps/x86_64/dl-lookupcfg.h (DL_EXTERN_PROTECTED_DATA): New.
* sysdeps/x86_64/dl-machine.h (elf_machine_type_class): Set class
to ELF_RTYPE_CLASS_EXTERN_PROTECTED_DATA for R_X86_64_GLOB_DAT.
PI_STATIC_AND_HIDDEN is always defined for i386. There is no need to
check PI_STATIC_AND_HIDDEN in sysdeps/i386/dl-machine.h.
[BZ #17775]
* sysdeps/i386/dl-machine.h (PI_STATIC_AND_HIDDEN): Removed.
(elf_machine_dynamic) [!PI_STATIC_AND_HIDDEN]: Likewise.
(elf_machine_load_address) [!PI_STATIC_AND_HIDDEN]: Likewise.
_dl_start_user in ld.so calls the local function _dl_init. There is no
need to go through PLT.
* sysdeps/i386/dl-machine.h (_dl_start_user): Remove @PLT
from "call _dl_init@PLT".
* sysdeps/x86_64/dl-machine.h (_dl_start_user): Likewise.
from "call _dl_init@PLT".
