Suggestions by Florian Weimer, Andreas Schwab, and Alexander Monakov.

See:
https://sourceware.org/pipermail/libc-alpha/2021-July/129356.html
https://sourceware.org/pipermail/libc-alpha/2021-July/129357.html
https://sourceware.org/pipermail/libc-alpha/2021-July/129361.html

Reviewed-by: Carlos O'Donell <carlos@redhat.com>

Commit 03e187a4 added a regression when an audit module does not have
libc as DT_NEEDED (although unusual it is possible).

Checked on x86_64-linux-gnu.

commit 3ec5d83d
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Sat Jan 25 14:19:40 2020 -0800

    x86-64: Avoid rep movsb with short distance [BZ #27130]

introduced some regressions on Intel processors without Fast Short REP
MOV (FSRM).  Add Avoid_Short_Distance_REP_MOVSB to avoid rep movsb with
short distance only on Intel processors with FSRM.  bench-memmove-large
on Skylake server shows that cycles of __memmove_evex_unaligned_erms
improves for the following data size:

                                  before    after    Improvement
length=4127, align1=3, align2=0:  479.38    349.25      27%
length=4223, align1=9, align2=5:  405.62    333.25      18%
length=8223, align1=3, align2=0:  786.12    496.38      37%
length=8319, align1=9, align2=5:  727.50    501.38      31%
length=16415, align1=3, align2=0: 1436.88   840.00      41%
length=16511, align1=9, align2=5: 1375.50   836.38      39%
length=32799, align1=3, align2=0: 2890.00   1860.12     36%
length=32895, align1=9, align2=5: 2891.38   1931.88     33%

This configuration exercises various --disable-* configure options.
It is expected to catch -Werror failures that only affect these
configurations.

The benchmark and tests must fail in case of allocation failure in the
implementation array.  Also annotate the x* allocators in support.h so
that the compiler has more information about them.

Reviewed-by: Florian Weimer <fweimer@redhat.com>

Tell the compiler that xmalloc family of allocators always return
non-NULL.  xrealloc in locale/programs also always returns non-NULL,
but that conflicts with default realloc behaviour and that of xrealloc
in libsupport, so keep it as is for now and resolve the differences
later.

Reviewed-by: Florian Weimer <fweimer@redhat.com>

Abort in the unlikely event that allocation fails when trying to
register a TLS destructor.

Reviewed-by: Florian Weimer <fweimer@redhat.com>

All references to libraries in the manual are without the .so prefix,
so do the same for libc_malloc_debug.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>

The setitimer fork hook, fork_itimer, needs to call malloc inside
__mach_setup_tls, so we need to unlock malloc before calling it.

mcheck and malloc-check no longer work with static binaries, so drop
those tests.

Reported-by: Samuel Thibault <samuel.thibault@gnu.org>
Tested-by: Samuel Thibault <samuel.thibault@gnu.org>
Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org>

These failures were caught while building glibc master for Fedora Rawhide
which is built with `-mtune=generic -msse2 -mfpmath=sse'.

These functions call the core allocator functions (realloc and malloc
respectively) and are hence guaranteed to allocate memory using the
correct functions when multiple allocators are interposed.  Having
these functions interposed in one allocator and not another may result
in confusion, hence discourage interposing them altogether.

Reviewed-by: Florian Weimer <fweimer@redhat.com>

1. Install <bits/platform/x86.h> for <sys/platform/x86.h> which includes
<bits/platform/x86.h>.
2. Rename HAS_CPU_FEATURE to CPU_FEATURE_PRESENT which checks if the
processor has the feature.
3. Rename CPU_FEATURE_USABLE to CPU_FEATURE_ACTIVE which checks if the
feature is active.  There may be other preconditions, like sufficient
stack space or further setup for AMX, which must be satisfied before the
feature can be used.

This fixes BZ #27958.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>

Remove unused code and declare __libc_mallopt when !IS_IN (libc) to
allow the debug hook to build with --disable-tunables.

Also, run tst-ifunc-isa-2* tests only when tunables are enabled since
the result depends on it.

Tested on x86_64.

Reported-by: Matheus Castanho <msc@linux.ibm.com>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>

84f7ce84 ("posix: Add glob64 with 64-bit time_t support") replaced
GLOB_NO_LSTAT with defining GLOB_LSTAT and GLOB_LSTAT64, but the posix
and gnu versions of the change were missing in the commit.

Reviewed-by: Lukasz Majewski <lukma@denx.de>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>

Reviewed-by: Lukasz Majewski <lukma@denx.de>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>

Interpose malloc_usable_size to return the correct mcheck value for
malloc_usable_size.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>

Make malloc hooks symbols compat-only so that new applications cannot
link against them and remove the declarations from the API.  Also
remove the unused malloc-hooks.h.

Finally, mark all symbols in libc_malloc_debug.so as compat so that
the library cannot be linked against.

Add a note about the deprecation in NEWS.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>

These deprecated functions are only safe to call from
__malloc_initialize_hook and as a result, are not useful in the
general case.  Move the implementations to libc_malloc_debug so that
existing binaries that need it will now have to preload the debug DSO
to work correctly.

This also allows simplification of the core malloc implementation by
dropping all the undumping support code that was added to make
malloc_set_state work.

One known breakage is that of ancient emacs binaries that depend on
this.  They will now crash when running with this libc.  With
LD_BIND_NOW=1, it will terminate immediately because of not being able
to find malloc_set_state but with lazy binding it will crash in
unpredictable ways.  It will need a preloaded libc_malloc_debug.so so
that its initialization hook is executed to allow its malloc
implementation to work properly.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>

The malloc-check debugging feature is tightly integrated into glibc
malloc, so thanks to an idea from Florian Weimer, much of the malloc
implementation has been moved into libc_malloc_debug.so to support
malloc-check.  Due to this, glibc malloc and malloc-check can no
longer work together; they use altogether different (but identical)
structures for heap management.  This should not make a difference
though since the malloc check hook is not disabled anywhere.
malloc_set_state does, but it does so early enough that it shouldn't
cause any problems.

The malloc check tunable is now in the debug DSO and has no effect
when the DSO is not preloaded.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>

Wean mtrace away from the malloc hooks and move them into the debug
DSO.  Split the API away from the implementation so that we can add
the API to libc.so as well as libc_malloc_debug.so, with the libc
implementations being empty.

Update localplt data since memalign no longer has any callers after
this change.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>

Now that mcheck no longer needs to check __malloc_initialized (and no
other third party hook can since the symbol is not exported), make the
variable boolean and static so that it is used strictly within malloc.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>

Split the mcheck implementation into the debugging hooks and API so
that the API can be replicated in libc and libc_malloc_debug.so.  The
libc APIs always result in failure.

The mcheck implementation has also been moved entirely into
libc_malloc_debug.so and with it, all of the hook initialization code
can now be moved into the debug library.  Now the initialization can
be done independently of libc internals.

With this patch, libc_malloc_debug.so can no longer be used with older
libcs, which is not its goal anyway.  tst-vfork3 breaks due to this
since it spawns shell scripts, which in turn execute using the system
glibc.  Move the test to tests-container so that only the built glibc
is used.

This move also fixes bugs in the mcheck version of memalign and
realloc, thus allowing removal of the tests from tests-mcheck
exclusion list.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>

Remove all malloc hook uses from core malloc functions and move it
into a new library libc_malloc_debug.so.  With this, the hooks now no
longer have any effect on the core library.

libc_malloc_debug.so is a malloc interposer that needs to be preloaded
to get hooks functionality back so that the debugging features that
depend on the hooks, i.e. malloc-check, mcheck and mtrace work again.
Without the preloaded DSO these debugging features will be nops.
These features will be ported away from hooks in subsequent patches.

Similarly, legacy applications that need hooks functionality need to
preload libc_malloc_debug.so.

The symbols exported by libc_malloc_debug.so are maintained at exactly
the same version as libc.so.

Finally, static binaries will no longer be able to use malloc
debugging features since they cannot preload the debugging DSO.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>

Make the __morecore and __default_morecore symbols compat-only and
remove their declarations from the API.  Also, include morecore.c
directly into malloc.c; this should ideally get merged into malloc in
a future cleanup.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>

Remove __after_morecore_hook from the API and finalize the symbol so
that it can no longer be used in new applications.  Old applications
using __after_morecore_hook will find that their hook is no longer
called.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>

Targets with base versions of 2.24 or later won't have
__malloc_initialize_hook because of which the tests will essentially
be the same as the regular malloc tests.  Avoid running them instead
and save time.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>

It uses pthread.

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>

Any FPU_STATUS write needs setting the FWE bit (31) whcih just provides
a "control signal" to enable explicit write (vs. the side-effect of FPU
instructions).  However this bit is RAZ and write-only, thus effectively
never stored in FPU_STATUS register. Thus when reading the register
there is no need to clear it. This shaves off a BCLR instruction from
the fe*exceptino family of functions and while no big deal still makes
sense to do.

This came up when debugging a race in math/test-fenv-tls [1]

[1]: https://github.com/foss-for-synopsys-dwc-arc-processors/linux/issues/54



Signed-off-by: Vineet Gupta <vgupta@synopsys.com>

Reviewed-by: Lukasz Majewski <lukma@denx.de>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>

Reviewed-by: Lukasz Majewski <lukma@denx.de>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>

Reviewed-by: Lukasz Majewski <lukma@denx.de>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>