The PowerPC64 linker edits medium model toc-indirect code to toc-pointer
relative:
addis r9,r2,tc_entry_for_var@toc@ha
ld r9,tc_entry_for_var@toc@l(r9)
becomes
addis r9,r2,(var-.TOC.)@ha
addi r9,r9,(var-.TOC.)@l
when "var" is known to be local to the binary. This isn't done for
small-model toc-indirect code, because "var" is almost guaranteed to
be too far away from .TOC. for a 16-bit signed offset. And, because
the analysis of which .toc entry can be removed becomes much more
complicated in objects that mix code models, they aren't removed if
any small-model toc sequence appears in an object file.
Unfortunately, glibc's build of ld.so smashes the needed objects
together in a ld -r linking stage. This means the GOT/TOC is left
with a whole lot of relative relocations which is untidy, but in
itself is not a serious problem. However, static-pie on powerpc64
bombs due to a segfault caused by one of the small-model accesses
before _dl_relocate_static_pie. (The very first one in rcrt1.o
passing start_addresses in r8 to __libc_start_main.)
So this patch makes all the toc/got accesses in assembly medium code
model, and a couple of functions hidden. By itself this is not
enough to give us working static-pie, but it is useful in isolation to
enable better linker optimisation.
There's a serious problem in libgcc too. libgcc ifuncs access the
AT_HWCAP words stored in the tcb with an offset from the thread
pointer (r13), but r13 isn't set at the time _dl_relocate_static_pie.
A followup patch will fix that.
Reviewed-by: Tulio Magno Quites Machado Filho <tuliom@linux.ibm.com>
Compilers may decide to put the rfv variable in .data rather than on
the stack. It's slightly better to put it in .data.rel.ro.local
instead. Regardles of that, making it const may enable further
optimisations. Found when examining relative relocations (GOT ones
in particular) as part of enabling static-pie for PowerPC64.
Copyright The GNU Toolchain Authors.
The comments on strlen() don't match what the actual code does. They
describe an older algorithm which is no longer in use. This change
replace the old comments with new ones describing the algorithm used.
I am a first time contributor, and I believe there is no need for
copyright assignment, since the file changed is not in the shared
source files list.
This patch only changes comments, but for safety I have run the tests in
my x64 ubuntu machine, with the following results:
Summary of test results:
5051 PASS
80 UNSUPPORTED
16 XFAIL
6 XPASS
Signed-off-by: Ricardo Bittencourt <bluepenguin@gmail.com>
If glibc is configured with --disable-default-pie and build on
s390 with -O3, the tests elf/tst-audit25a and elf/tst-audit25b are
failing as there are additional la_symbind lines for free and malloc.
It turns out that those belong to the executable. In fact those are
the PLT-stubs. Furthermore la_symbind is also called for calloc and
realloc symbols, but those belong to libc.
Those functions are not called at all, but dlsym'ed in
elf/dl-minimal.c:
__rtld_malloc_init_real (struct link_map *main_map)
{
...
void *new_calloc = lookup_malloc_symbol (main_map, "calloc", &version);
void *new_free = lookup_malloc_symbol (main_map, "free", &version);
void *new_malloc = lookup_malloc_symbol (main_map, "malloc", &version);
void *new_realloc = lookup_malloc_symbol (main_map, "realloc", &version);
...
}
Therefore, this commit just ignored symbols with LA_SYMB_DLSYM flag.
Reviewed-by: Adheemrval Zanella <adhemerval.zanella@linaro.org>
In most cases the simple/stupid/builtin functions were in there to
benchmark optimized implementations against. Only in some cases the
functions are used to check expected results.
Remove these tests from IMPL() and only keep them in wherever they're
used for a specific purpose, e.g. to generate expected results.
This improves timing of `make subdirs=string` by over a minute and a
half (over 15%) on a Whiskey Lake laptop.
Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
Reviewed-by: Noah Goldstein <libc-alpha@sourceware.org>
Looks like an oversight in memcpy tests resulted in s2 and s1 not being
swapped for the second iteration of the memcpy test. Fix it. Also fix
a formatting nit.
Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
The __closefrom_fallback tries to get a available file descriptor
if the initial open ("/proc/self/fd/", ...) fails. It assumes the
failure would be only if procfs is not mount (ENOENT), however if
the the proc file is not accessible (due some other kernel filtering
such apparmor) it will iterate over a potentially large file set
issuing close calls.
It should only try the close fallback if open returns EMFILE,
ENFILE, or ENOMEM.
Checked on x86_64-linux-gnu.
-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>
For sparc64 is the same as the generic implementation, while for
sparc32 the builtin generates the same code.
Checked on sparc64-linux-gnu and sparcv9-linux-gnu.
If the build itself is run in a container, we may not be able to
fully set up a nested container for test-container testing.
Notably is the mounting of /proc, since it's critical that it
be mounted from within the same PID namespace as its users, and
thus cannot be bind mounted from outside the container like other
mounts.
This patch defaults to using the parent's PID namespace instead of
creating a new one, as this is more likely to be allowed.
If the test needs an isolated PID namespace, it should add the "pidns"
command to its init script.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Recent changes in test-strncasecmp and test-strncmp pushed the run time
of the tests above the 4 minute limit specified in test-string.h on an
arm tester machine.
The GNU extension for realpath states that if the path resolution fails
with ENOENT or EACCES and the resolved buffer is non-NULL, it will
contain part of the path that failed resolution.
commit 949ad78a18 broke this when it
omitted the copy on failure. Bring it back partially to continue
supporting this GNU extension.
Resolves: BZ #28996
Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
Reviewed-by: Andreas Schwab <schwab@linux-m68k.org>
Just a few QOL changes.
1. Prefer `add` > `lea` as it has high execution units it can run
on.
2. Don't break macro-fusion between `test` and `jcc`
3. Reduce code size by removing gratuitous padding bytes (-90
bytes).
geometric_mean(N=20) of all benchmarks New / Original: 0.959
All string/memory tests pass.
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
Just a few small QOL changes.
1. Prefer `add` > `lea` as it has high execution units it can run
on.
2. Don't break macro-fusion between `test` and `jcc`
geometric_mean(N=20) of all benchmarks New / Original: 0.973
All string/memory tests pass.
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
It is not a "buffer overflow detected" but an out of range
bit on fd_set
Signed-off-by: Cristian Rodríguez <crrodriguez@opensuse.org>
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
The rational is:
1. SSE42 has nearly identical logic so any benefit is minimal (3.4%
regression on Tigerlake using SSE42 versus AVX across the
benchtest suite).
2. AVX2 version covers the majority of targets that previously
prefered it.
3. The targets where AVX would still be best (SnB and IVB) are
becoming outdated.
All in all the saving the code size is worth it.
All string/memory tests pass.
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
Slightly faster method of doing TOLOWER that saves an
instruction.
Also replace the hard coded 5-byte no with .p2align 4. On builds with
CET enabled this misaligned entry to strcasecmp.
geometric_mean(N=40) of all benchmarks New / Original: .920
All string/memory tests pass.
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
Slightly faster method of doing TOLOWER that saves an
instruction.
Also replace the hard coded 5-byte no with .p2align 4. On builds with
CET enabled this misaligned entry to strcasecmp.
geometric_mean(N=40) of all benchmarks New / Original: .894
All string/memory tests pass.
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
