This commit separates allocating and raising exceptions. This
simplifies catching and re-raising them because it is no longer
necessary to make a temporary, on-stack copy of the exception message.
It is no longer needed since commit 6c444ad6e9
(elf: Do not use memalign for TCB/TLS blocks allocation [BZ #17730]).
Applications do not link against ld.so and will use the definition in
libc.so, so there is no ABI impact.
This change moves the main implementation of _dl_catch_error,
_dl_signal_error to libc.so, where TLS variables can be used
directly. This removes a writable function pointer from the
rtld_global variable.
For use during initial relocation, minimal implementations of these
functions are provided in ld.so. These are eventually interposed
by the libc.so implementations. This is implemented by compiling
elf/dl-error-skeleton.c twice, via elf/dl-error.c and
elf/dl-error-minimal.c.
As a side effect of this change, the static version of dl-error.c
no longer includes support for the
_dl_signal_cerror/_dl_receive_error mechanism because it is only
used in ld.so.
on s390x the test elf/check-localplt is failing after recent commits:
"elf: Do not use memalign for TCB/TLS blocks allocation [BZ #17730]"
"elf: Avoid using memalign for TLS allocations [BZ #17730]"
"elf: dl-minimal malloc needs to respect fundamental alignment"
due to "Missing required PLT reference: ld.so: __libc_memalign".
After the commits __libc_memalign is only called in elf/dl-minimal.c in
malloc() function in ld.so and gcc -O2/-O3 leads to R_390_GLOB_DAT
instead of R_390_JMP_SLOT. __libc_memalign is called via
function-pointer loaded from GOT instead of calling via a plt-stub. In
this case there is the R_390_GLOB_DAT relocation in section .rela.dyn
instead of R_390_JMP_SLOT in .rela.plt.
This patch marks ld.so: __libc_memalign with R_390_GLOB_DAT in
localplt.data to allow both relocations.
If build with -fno-optimize-sibling-calls or on s390(31bit) a
R_390_JMP_SLOT is generated.
ChangeLog:
* sysdeps/unix/sysv/linux/s390/localplt.data: Mark
ld.so: __libc_memalign with "+ RELA R_390_GLOB_DAT".
For maximum paranoia we run ld.so through the normal set
of tests for all of the shared libraries. This includes
running ld.so through check-localplt, check-textrel, and
check-execstack. While none of these should trigger any
failures given the way ld.so is built, it might possibly
fail if a developer does something wrong. This paranoia
was triggered by a discussion over the use of __strcpy
vs. strcpy [1] and if the symbol could leak and use the
libc.so version.
The check-localplt test fails right away because localplt.data
needs updating for all arches. By default we add 6 new symbols:
__tls_get_addr, __libc_memalign, malloc, calloc, realloc and
free. Other machines like i386, power, and s390 require some
different symbol sets e.g. ___tls_get_addr vs. __tls_get_addr
for i386.
Verified for i386
Verified for x86_64
Verified for ppc32
Verified for ppc64
Verified for ppc64le
Verified for arm
Verified for aarch64
Verified for s390
Verified for s390x
Guessed for alpha
Guessed for ia64
Guessed for m68k
Guessed for microblaze
Guessed for sparc32
Guessed for sparc64
Defaults for sh
Defaults for mips
Defaults for hppa
Defaults for tile
Machine manintainers notified to double check the data
used in localplt.data.
[1] https://sourceware.org/ml/libc-alpha/2014-10/msg00548.html
