Joseph Myers [Mon, 9 Jan 2017 16:09:53 +0000 (16:09 +0000)]
Update MicroBlaze localplt.data.
This patch updates the MicroBlaze localplt.data based on the results
of a build with build-many-glibcs.py. This is simply an empirical
update; quite possibly the port could be optimized to remove more
local PLT entry usage.
Tested (compilation tests) with build-many-glibcs.py.
Commit 38765ab68f329fd moved the bzero, bcopy, and explicit_bzero
fortified macros to a common header (strings_fortified.h). However
the side effect is a fortified explicit_bzero is defined when including
only strings.h.
This patch moves back the fortified explicit_bzero definition to
strings3.h header.
Checked on x86_64-linux-gnu.
* string/bits/strings_fortified.h (explicit_bzero): Move back to ..
* string/bits/string3.h: ... here.
Joseph Myers [Thu, 5 Jan 2017 23:15:47 +0000 (23:15 +0000)]
Make fallback fesetexceptflag always succeed (bug 21028).
The fallback implementation of fesetexceptflag currently fails if any
exceptions are specified. It should always succeed, because the
exception state is always that all exceptions (if any are defined in
<fenv.h> but not supported in this configuration) are always clear,
just as fallback fetestexcept always succeeds and fallback fesetenv
always succeeds unless asked to set FE_NOMASK_ENV.
This patch fixes it accordingly. Together with the patch to
test-fexcept.c to allow feraiseexcept to fail in another place, this
stops that test from failing for MIPS soft-float.
Tested for mips64 soft-float.
[BZ #21028]
* math/fsetexcptflg.c (__fesetexceptflag): Always return 0.
* math/test-fexcept.c (test_set): Allow failure of feraiseexcept
if EXCEPTION_TESTS returns false.
Use fortify macros for b{zero,copy} along decl from strings.h
As described in BZ#20558, bzero and bcopy declaration can only benefit
from fortified macros when decl came from string.h and when __USE_MISC
is defined (default behaviour).
This is due no standard includes those functions in string.h, so they
are only declared if __USE_MISC is defined (as pointed out in comment 4).
However fortification should be orthogona to other features test macros,
i.e, any function should be fortified if that function is declared.
To fix this behavior, the patch moved the bzero, bcopy, and
__explicit_bzero_chk to a common header (string/bits/strings_fortified.h)
and explicit fortified inclusion macros similar to string.h is added
on strings.h. This allows to get fortified declarions by only including
strings.h.
Checked on x86_64-linux-gnu and along on a bootstrap installation to check
if the fortified are correctly triggered with example from bug report.
Joseph Myers [Thu, 5 Jan 2017 17:39:38 +0000 (17:39 +0000)]
Increase some test timeouts.
This patch increases timeouts on some tests I've observed timing out.
elf/tst-tls13 and iconvdata/tst-loading both dynamically load many
objects and so are slow when testing over NFS. They had timeouts set
from before the default changed from 2 to 20 seconds; this patch
removes those old settings, so effectively increasing the timeout to
20 seconds (from 3 and 10 seconds respectively).
malloc/tst-malloc-thread-fail.c and malloc/tst-mallocfork2.c are slow
on slow systems and so I set a fairly arbitrary 100 second timeout,
which seems to suffice on the system where I saw them timing out.
nss/tst-cancel-getpwuid_r.c and nss/tst-nss-getpwent.c are slow on
systems with a large passwd file; I set timeouts that empirically
worked for me. (It seems tst-cancel-getpwuid_r.c is hitting the
100000 getpwuid_r call limit in my testing, with each call taking a
bit over 0.007 seconds, so 700 seconds for the test.)
* elf/tst-tls13.c (TIMEOUT): Remove.
* iconvdata/tst-loading.c (TIMEOUT): Likewise.
* malloc/tst-malloc-thread-fail.c (TIMEOUT): Increase to 100.
* malloc/tst-mallocfork2.c (TIMEOUT): Define to 100.
* nss/tst-cancel-getpwuid_r.c (TIMEOUT): Define to 900.
* nss/tst-nss-getpwent.c (TIMEOUT): Define to 300.
Joseph Myers [Thu, 5 Jan 2017 17:35:53 +0000 (17:35 +0000)]
Fix MIPS n64 readahead (bug 21026).
As noted in bug 20126, MIPS n64 uses an incorrect implementation of
readahead intended for 32-bit systems. This patch adds a
syscalls.list entry to fix this. An updated version of the
consolidation patch
<https://sourceware.org/ml/libc-alpha/2016-09/msg00527.html> could
remove this syscalls.list entry again.
Tested with compilation (only) for mips64; the nature of the syscall
doesn't allow for a glibc test to detect this issue.
[BZ #21026]
* sysdeps/unix/sysv/linux/mips/mips64/n64/syscalls.list
(readahead): New syscall entry.
Joseph Myers [Wed, 4 Jan 2017 23:33:31 +0000 (23:33 +0000)]
Fix string/tester.c for GCC 7 -Wstringop-overflow=.
GCC 7 has a -Wstringop-overflow= warning that includes warning for
strncat with a size specified that is larger than the size of the
buffer (which is dubious usage, but valid at runtime if in fact there
isn't an overflow with the particular buffer contents present).
string/tester.c tests such cases; this patch arranges for this warning
to be ignored around relevant strncat calls.
Tested compilation for aarch64 (GCC mainline) with
build-many-glibcs.py; did execution testing for x86_64 (GCC 5).
* string/tester.c (test_strncat): Disable -Wstringop-overflow=
around tests of strncat with large sizes.
Joseph Myers [Wed, 4 Jan 2017 23:32:14 +0000 (23:32 +0000)]
Fix malloc/ tests for GCC 7 -Walloc-size-larger-than=.
GCC 7 has a -Walloc-size-larger-than= warning for allocations of half
the address space or more. This causes errors building glibc tests
that deliberately test failure of very large allocations. This patch
arranges for this warning to be ignored around the problematic
function calls.
Tested compilation for aarch64 (GCC mainline) with
build-many-glibcs.py; did execution testing for x86_64 (GCC 5).
* malloc/tst-malloc.c: Include <libc-internal.h>.
(do_test): Disable -Walloc-size-larger-than= around tests of
malloc with negative sizes.
* malloc/tst-mcheck.c: Include <libc-internal.h>.
(do_test): Disable -Walloc-size-larger-than= around tests of
malloc and realloc with negative sizes.
* malloc/tst-realloc.c: Include <libc-internal.h>.
(do_test): Disable -Walloc-size-larger-than= around tests of
realloc with negative sizes.
Joseph Myers [Wed, 4 Jan 2017 23:29:42 +0000 (23:29 +0000)]
Update libm-test XFAILs for ibm128 format.
This patch cleans up and updates the libm-test XFAILs for the ibm128
format. More of them are changed to use a new ibm128-libgcc
conditional, to reflect that they are not in fact needed if you've
patched libgcc to fix the known issues (at substantial performance
cost). Many additional XFAILs are added for tests that fail with
unpatched libgcc (most but not all of them xfail-rounding).
Note that further such fixes will be needed for test-ldouble actually
to pass with default libgcc (in particular, XFAILs for pow tests and
for various affected tests directly embedded in libm-test.inc). With
patched libgcc, there may be a few XFAILs needed but the results are
already substantially clean apart from a few ulps differences.
Tested for powerpc.
* math/libm-test.inc (TEST_COND_ibm128_libgcc): New macro.
(init_max_error) [TEST_COND_ibm128]: Increase maximum error
allowed to 16 ulps.
* math/auto-libm-test-in: Change most XFAILs for ibm128 to use
ibm128-libgcc. XFAIL more tests for ibm128-libgcc.
* math/auto-libm-test-out: Regenerated.
This commit moves one step towards the deprecation of wrappers that
use _LIB_VERSION / matherr / __kernel_standard functionality, by
adding the suffix '_compat' to their filenames and adjusting Makefiles
and #includes accordingly.
New template wrappers that do not use such functionality will be added
by future patches and will be first used by the float128 wrappers.
Joseph Myers [Wed, 4 Jan 2017 18:12:14 +0000 (18:12 +0000)]
Fix MicroBlaze bits/setjmp.h for C++.
For MicroBlaze, setjmp/check-installed-headers-cxx fails with:
../setjmp/setjmp.h:34:8: error: '__jmp_buf_tag' has a field '__jmp_buf_tag::__jmpbuf' whose type depends on the type '<unnamed struct>' which has no linkage [-Werror=subobject-linkage]
This patch fixes this in the same way as for some other architectures:
the struct used for the internal __jmp_buf type is given the tag
__jmp_buf_internal_tag.
Tested (compilation tests) with build-many-glibcs.py.
* sysdeps/microblaze/bits/setjmp.h (__jmp_buf): Give struct tag
__jmp_buf_internal_tag.
Joseph Myers [Wed, 4 Jan 2017 17:15:39 +0000 (17:15 +0000)]
Make MIPS soft-fp preserve NaN payloads for NAN2008.
This corresponds to a patch applied to libgcc. In glibc it doesn't
actually affect much (only fma, I think).
The MIPS sfp-machine.h files have an _FP_CHOOSENAN implementation
which emulates hardware semantics of not preserving signaling NaN
payloads for an operation with two NaN arguments (although that
doesn't suffice to avoid sNaN payload preservation in any case with
just one NaN argument).
However, those are only hardware semantics in the legacy NaN case; in
the NAN2008 case, the architecture documentation says hardware
preserves payloads in such cases. Furthermore, this implementation
assumes legacy NaN semantics, so in the NAN2008 case the
implementation actually has the effect of preserving sNaN payloads but
not preserving qNaN payloads, when both should be preserved.
This patch fixes the code just to copy from the first argument.
Tested for mips64 soft-float.
* sysdeps/mips/mips32/sfp-machine.h (_FP_CHOOSENAN): Always
preserve NaN payload if [__mips_nan2008].
* sysdeps/mips/mips64/sfp-machine.h (_FP_CHOOSENAN): Likewise.
Many linknamespace tests fail for MicroBlaze because __backtrace (as
brought in by libc_fatal.c) uses an inline function get_frame_size
which is not declared static. This patch fixes it to be declared
static.
Tested (compilation tests) with build-many-glibcs.py.
[BZ #21022]
* sysdeps/microblaze/backtrace.c (get_frame_size): Make static.
Joseph Myers [Tue, 3 Jan 2017 21:05:46 +0000 (21:05 +0000)]
Update i386 libm-test-ulps.
When testing changes to i386 libm functions (that are shadowed for
i686 builds by i686 versions) recently, I saw that the plain i386
libm-test-ulps (as opposed to the i686 multiarch version) needed
updating for tests that had been added since it was last updated.
This patch updates it accordingly.
Since commit 6e46de42fe16 default strcat implementation is essentially
the same for specialized ia64 and powerpc ones. This patch removes the
redundant implementation and adjust powerpc64 ifunc code to use the
default one.
Checked on powerpc32-linux-gnu (default and power4) and ia64-linux build
and on powerpc64le-linux-gnu.
* sysdeps/ia64/strcat.c: Remove file.
* sysdeps/powerpc/strcat.c: Likewise.
* sysdeps/powerpc/powerpc64/multiarch/strcat-power7.c: Use default
C implementation.
* sysdeps/powerpc/powerpc64/multiarch/strcat-power8.c: Likewise.
* sysdeps/powerpc/powerpc64/multiarch/strcat-ppc64.c: Likewise.
powerpc: Fix write-after-destroy in lock elision [BZ #20822]
The update of *adapt_count after the release of the lock causes a race
condition when thread A unlocks, thread B continues and destroys the
mutex, and thread A writes to *adapt_count.
Joseph Myers [Tue, 3 Jan 2017 18:45:28 +0000 (18:45 +0000)]
Fix math/test-fenvinline for no-exceptions configurations.
This patch fixes math/test-fenvinline.c to stop it failing in
no-exceptions configurations (where some exception macros are defined
but may not be supported at runtime). The relevant parts of the test
are disabled in that case; some parts can still run (and the rounding
mode tests are written in a way such that they work even if the
rounding modes aren't supported).
Tested for mips64 soft-float, and for x86_64 to make sure the tests
still run when the exceptions are supported.
* math/test-fenvinline.c (do_test): Disable tests of raised
exceptions if !EXCEPTION_TESTS (FLOAT).
Joseph Myers [Tue, 3 Jan 2017 15:11:17 +0000 (15:11 +0000)]
Fix elf/tst-ldconfig-X for cross testing.
elf/Makefile passes arguments to tst-ldconfig-X.sh that are different
from what it expects, so resulting in the test failing in cross
testing. This patch corrects the arguments passed (the script itself
has correct logic for cross testing, it's just the Makefile that's
wrong).
Tested for powerpc (cross testing) and for x86_64 (native testing).
* elf/Makefile ($(objpfx)tst-ldconfig-X.out): Correct arguments
passed to tst-ldconfig-X.sh.
Joseph Myers [Mon, 2 Jan 2017 23:09:25 +0000 (23:09 +0000)]
Fix MIPS n32 lseek, lseek64 (bug 21019).
The lseek consolidation broke lseek64 for MIPS n32, so resulting in
io/test-lfs failing with an incorrect return from ftello64. This
configuration uses the lseek syscall with a 64-bit return value; as
the C syscall macros return long, they cannot be used in this case and
so an assembly implementation is needed; accordingly, this patch adds
lseek64 back to syscalls.list for this configuration.
lseek was also broken, truncating the result without checking for
overflow. lseek however was already broken before the consolidation;
it aliased lseek64 so would return an out-of-range value, resulting in
architecturally undefined behavior in the caller if it tried to use a
non-sign-extended value with a 32-bit instruction. This patch adds a
custom lseek implementation in C for n32, which calls __lseek64 to get
the 64-bit value then checks for overflow.
Because the prior lseek breakage did not show in test results, and the
lseek64 breakage showed only indirectly through tests of ftello64,
test coverage was clearly inadequate. This patch extends
io/test-lfs.c to test the lseek64 return value (at a point where it
has already seeked over 2GB into a file), and then to test the lseek
return value (with the latter's expectations depending on whether
off_t is smaller than off64_t).
Tested for mips64 n32. Also tested test-lfs for x86_64 and x86, where
as expected it passes.
[BZ #21019]
* sysdeps/unix/sysv/linux/mips/mips64/n32/syscalls.list (lseek64):
New syscall entry.
* sysdeps/unix/sysv/linux/mips/mips64/n32/lseek.c: New file.
* io/test-lfs.c (do_test): Test offset returned from lseek64 and
lseek.
The 32-bit powerpc configurations in build-many-glibcs.py were failing
to cover the powerpc32 multiarch code at all, because that code is
only built for power4 and above configurations. This patch adds a
32-bit power4 configuration so that at least some of that multiarch
code gets build-tested. (This is preparation for reviewing the w_*
file renaming, which affects such powerpc32 multiarch files.)
* scripts/build-many-glibcs.py (Context.add_all_configs): Add
power4 glibc for powerpc-linux-gnu.
The command IPC_STAT of semctl expects an union semun in its fourth
argument instead of struct semid_ds *. This can cause failures on
powerpc32-linux-gnu.
Checked on x86_64-linux-gnu, i686-linux-gnu, and powerpc32-linux-gnu
(qemu system emulation).
Joseph Myers [Mon, 2 Jan 2017 20:47:17 +0000 (20:47 +0000)]
Fix math/test-nearbyint-except for no-exceptions configurations.
The test math/test-nearbyint-except conditions some of its tests on an
EXCEPTION_TESTS call, not not all that need such a condition. This
patch fixes it to use such a conditional for all its tests and to
return 77 (UNSUPPORTED) if none of the floating-point types tested
support exceptions.
Tested for mips64 soft float (where the test previously failed and is
now UNSUPPORTED); also tested for x86_64 to make sure the test still
PASSes in exceptions-supported cases.
* math/test-nearbyint-except.c: Include <stdbool.h>.
(any_supported): New variable.
(TEST_FUNC): Return early if !EXCEPTION_TESTS (FLOAT). Otherwise
set any_supported.
(do_test): Return 77 if no floating-point type supported
exceptions.
Joseph Myers [Mon, 2 Jan 2017 20:28:36 +0000 (20:28 +0000)]
Correct MIPS math-tests.h condition for sNaN payload preservation.
Testing for MIPS soft float shows that the issue with NaN payload
preservation applies to soft float as well as hard float: the
sfp-machine.h emulates hardware non-preservation semantics, although
only for the case of two NaN arguments.
This patch duly changes the MIPS math-tests.h to expect such
non-preservation for soft float as well as hard float. The issue in
the NAN2008 case for which I posted
<https://gcc.gnu.org/ml/gcc-patches/2017-01/msg00034.html>, of sNaN
payloads being preserved but qNaN payloads not being preserved, is not
currently an issue for glibc tests because we don't have any tests
that check for qNaN payloads being preserved by arithmetic, so a
simple __mips_nan2008 conditional suffices without needing compiler
version checks in the __mips_nan2008 case.
Tested for mips64 soft float.
* sysdeps/mips/math-tests.h (SNAN_TESTS_PRESERVE_PAYLOAD): Do not
condition on [__mips_hard_float].
Similar to BZ#19387 and BZ#20971, both i686 memchr optimized assembly
implementations (memchr-sse2-bsf and memchr-sse2) do not handle the
size overflow correctly.
It is shown by the new tests added by commit 3daef2c8ee4df29, where
both implementation fails with size as SIZE_MAX.
This patch uses a similar strategy used on 3daef2c8ee4df2, where
saturared math is used for overflow case.
Joseph Myers [Sun, 1 Jan 2017 00:26:24 +0000 (00:26 +0000)]
Update copyright dates not handled by scripts/update-copyrights.
I've updated copyright dates in glibc for 2017. This is the patch for
the changes not generated by scripts/update-copyrights and subsequent
build / regeneration of generated files.
Please remember to include 2017 in the dates for any new files added
in future (which means updating any existing uncommitted patches you
have that add new files to use the new copyright dates in them).
Enhance --enable-tunables to select tunables frontend at build time
At the GNU Tools Cauldron 2016, the state of the current tunables
patchset was considered OK with the addition of a way to select the
frontend to be used for the tunables. That is, to avoid being locked
in to one type of frontend initially, it should be possible to build
tunables with a different frontend with something as simple as a
configure switch.
To that effect, this patch enhances the --enable-tunables option to
accept more values than just 'yes' or 'no'. The current frontend (and
default when enable-tunables is 'yes') is called 'valstring', to
select the frontend where a single environment variable is set to a
colon-separated value string. More such frontends can be added in
future.
* Makeconfig (have-tunables): Check for non-negative instead
of positive.
* configure.ac: Add 'valstring' as a valid value for
--enable-tunables.
* configure: Regenerate.
* elf/Makefile (have-tunables): Check for non-negative instead
of positive.
(CPPFLAGS-dl-tunables.c): Define TUNABLES_FRONTEND for
dl-tunables.c.
* elf/dl-tunables.c (GLIBC_TUNABLES): Define only when
TUNABLES_FRONTEND == TUNABLES_FRONTEND_valstring.
(tunables_strdup): Likewise.
(disable_tunables): Likewise.
(parse_tunables): Likewise.
(__tunables_init): Process GLIBC_TUNABLES envvar only when.
TUNABLES_FRONTEND == TUNABLES_FRONTEND_valstring.
* elf/dl-tunables.h (TUNABLES_FRONTEND_valstring): New macro.
(TUNABLES_FRONTEND_yes): New macro, define as
TUNABLES_FRONTEND_valstring by default.
* manual/install.texi: Document new acceptable values for
--enable-tunables.
* INSTALL: Regenerate.
Initialize tunable list with the GLIBC_TUNABLES environment variable
Read tunables values from the users using the GLIBC_TUNABLES
environment variable. The value of this variable is a colon-separated
list of name=value pairs. So a typical string would look like this:
* config.make.in (have-loop-to-function): Define.
* elf/Makefile (CFLAGS-dl-tunables.c): Add
-fno-tree-loop-distribute-patterns.
* elf/dl-tunables.c: Include libc-internals.h.
(GLIBC_TUNABLES): New macro.
(tunables_strdup): New function.
(parse_tunables): New function.
(min_strlen): New function.
(__tunables_init): Use the new functions and macro.
(disable_tunable): Disable tunable from GLIBC_TUNABLES.
* malloc/tst-malloc-usable-tunables.c: New test case.
* malloc/tst-malloc-usable-static-tunables.c: New test case.
* malloc/Makefile (tests, tests-static): Add tests.
The tunables framework allows us to uniformly manage and expose global
variables inside glibc as switches to users. tunables/README has
instructions for glibc developers to add new tunables.
Tunables support can be enabled by passing the --enable-tunables
configure flag to the configure script. This patch only adds a
framework and does not pose any limitations on how tunable values are
read from the user. It also adds environment variables used in malloc
behaviour tweaking to the tunables framework as a PoC of the
compatibility interface.
* manual/install.texi: Add --enable-tunables option.
* INSTALL: Regenerate.
* README.tunables: New file.
* Makeconfig (CPPFLAGS): Define TOP_NAMESPACE.
(before-compile): Generate dl-tunable-list.h early.
* config.h.in: Add HAVE_TUNABLES.
* config.make.in: Add have-tunables.
* configure.ac: Add --enable-tunables option.
* configure: Regenerate.
* csu/init-first.c (__libc_init_first): Move
__libc_init_secure earlier...
* csu/init-first.c (LIBC_START_MAIN):... to here.
Include dl-tunables.h, libc-internal.h.
(LIBC_START_MAIN) [!SHARED]: Initialize tunables for static
binaries.
* elf/Makefile (dl-routines): Add dl-tunables.
* elf/Versions (ld): Add __tunable_set_val to GLIBC_PRIVATE
namespace.
* elf/dl-support (_dl_nondynamic_init): Unset MALLOC_CHECK_
only when !HAVE_TUNABLES.
* elf/rtld.c (process_envvars): Likewise.
* elf/dl-sysdep.c [HAVE_TUNABLES]: Include dl-tunables.h
(_dl_sysdep_start): Call __tunables_init.
* elf/dl-tunable-types.h: New file.
* elf/dl-tunables.c: New file.
* elf/dl-tunables.h: New file.
* elf/dl-tunables.list: New file.
* malloc/tst-malloc-usable-static.c: New test case.
* malloc/Makefile (tests-static): Add it.
* malloc/arena.c [HAVE_TUNABLES]: Include dl-tunables.h.
Define TUNABLE_NAMESPACE.
(DL_TUNABLE_CALLBACK (set_mallopt_check)): New function.
(DL_TUNABLE_CALLBACK_FNDECL): New macro. Use it to define
callback functions.
(ptmalloc_init): Set tunable values.
* scripts/gen-tunables.awk: New file.
* sysdeps/mach/hurd/dl-sysdep.c: Include dl-tunables.h.
(_dl_sysdep_start): Call __tunables_init.
Florian Weimer [Sat, 31 Dec 2016 11:20:49 +0000 (12:20 +0100)]
support: Use support_record_failure consistently
This causes more test programs to link in the support_record_failure
function, which triggers an early call to mmap from an ELF
constructor, but this should not have side effects intefering
with the functionality actually under test (unlike, say, a call
to malloc).
Torvald Riegel [Wed, 25 May 2016 21:43:36 +0000 (23:43 +0200)]
New condvar implementation that provides stronger ordering guarantees.
This is a new implementation for condition variables, required
after http://austingroupbugs.net/view.php?id=609 to fix bug 13165. In
essence, we need to be stricter in which waiters a signal or broadcast
is required to wake up; this couldn't be solved using the old algorithm.
ISO C++ made a similar clarification, so this also fixes a bug in
current libstdc++, for example.
We can't use the old algorithm anymore because futexes do not guarantee
to wake in FIFO order. Thus, when we wake, we can't simply let any
waiter grab a signal, but we need to ensure that one of the waiters
happening before the signal is woken up. This is something the previous
algorithm violated (see bug 13165).
There's another issue specific to condvars: ABA issues on the underlying
futexes. Unlike mutexes that have just three states, or semaphores that
have no tokens or a limited number of them, the state of a condvar is
the *order* of the waiters. A waiter on a semaphore can grab a token
whenever one is available; a condvar waiter must only consume a signal
if it is eligible to do so as determined by the relative order of the
waiter and the signal.
Therefore, this new algorithm maintains two groups of waiters: Those
eligible to consume signals (G1), and those that have to wait until
previous waiters have consumed signals (G2). Once G1 is empty, G2
becomes the new G1. 64b counters are used to avoid ABA issues.
This condvar doesn't yet use a requeue optimization (ie, on a broadcast,
waking just one thread and requeueing all others on the futex of the
mutex supplied by the program). I don't think doing the requeue is
necessarily the right approach (but I haven't done real measurements
yet):
* If a program expects to wake many threads at the same time and make
that scalable, a condvar isn't great anyway because of how it requires
waiters to operate mutually exclusive (due to the mutex usage). Thus, a
thundering herd problem is a scalability problem with or without the
optimization. Using something like a semaphore might be more
appropriate in such a case.
* The scalability problem is actually at the mutex side; the condvar
could help (and it tries to with the requeue optimization), but it
should be the mutex who decides how that is done, and whether it is done
at all.
* Forcing all but one waiter into the kernel-side wait queue of the
mutex prevents/avoids the use of lock elision on the mutex. Thus, it
prevents the only cure against the underlying scalability problem
inherent to condvars.
* If condvars use short critical sections (ie, hold the mutex just to
check a binary flag or such), which they should do ideally, then forcing
all those waiter to proceed serially with kernel-based hand-off (ie,
futex ops in the mutex' contended state, via the futex wait queues) will
be less efficient than just letting a scalable mutex implementation take
care of it. Our current mutex impl doesn't employ spinning at all, but
if critical sections are short, spinning can be much better.
* Doing the requeue stuff requires all waiters to always drive the mutex
into the contended state. This leads to each waiter having to call
futex_wake after lock release, even if this wouldn't be necessary.
Joseph Myers [Sat, 31 Dec 2016 00:40:59 +0000 (00:40 +0000)]
Add fromfp functions.
TS 18661-1 defines fromfp functions (fromfp, fromfpx, ufromfp,
ufromfpx, and float and long double variants) to convert from
floating-point to an integer type with any signedness and any given
width up to that of intmax_t, in any of the five IEEE rounding modes
(the usual four for binary floating point, plus rounding to nearest
with ties rounding away from zero), with control of whether in-range
non-integer values should result in the "inexact" exception being
raised. This patch implements these functions for glibc.
These implementations are (apart from raising exceptions) pure integer
implementations; it's entirely possible optimized versions could be
devised for some architectures. A common math/fromfp.h header
provides various common helper code that can readily be shared between
the implementations for different types. For each type, the bulk of
the implementation is also shared between the four functions, with
wrappers that define UNSIGNED and INEXACT macros appropriately before
including the main implementation.
As the functions return intmax_t and uintmax_t without math.h being
allowed to expose those typedef names, they are declared using
__intmax_t and __uintmax_t as obtained from <bits/types.h>.
The FP_INT_* rounding direction macros are defined as ascending
integers in the order the names are listed in the TS; I see no
significant value in allowing architectures to vary the values of
them.
The libm-test machinery is duly adapted to handle unsigned int
arguments, and intmax_t and uintmax_t results. Because each test
input is generally tested for four functions, five rounding modes and
several different widths, the libm-test.inc additions are very large.
Thus, the diffs in the body of this message exclude the libm-test.inc
changes, with the full patch being attached gzipped. The bulk of the
new tests were generated (expanded from a test input plus rounding
results and information about where it lies in the relevant interval
between integers, to libm-test tests for all relevant combinations of
function, rounding direction and width) by a script that's included in
the patch as math/gen-fromfp-tests.py (input data
math/gen-fromfp-tests-inputs); as an ad hoc script that's not really
expected to be rerun, it's not very polished, but it's at least
plausibly useful for adding any further tests for these functions in
future. I may split the libm-test tests up by function in future (so
both libm-test.inc and auto-libm-test-out are split into separate
files, and the tests for each function are also built and run
separately), but not for 2.25.
For no obvious reason, adding tgmath tests for the new functions
resulted in -Wuninitialized errors from test-tgmath.c about the
variable i being used uninitialized. Those errors were correct - the
variable is read by the frexp version in test-tgmath.c (where real
frexp would write through that pointer instead of reading it) - but I
don't know why this patch would result in the pre-existing issue being
newly detected. The patch initializes the variable to avoid those
errors.
With these changes, glibc 2.25 should have all the library features
from TS 18661-1 other than the functions that round result to narrower
type (and constant rounding directions, but I'm considering those
mainly a compiler feature not a library one).
Tested for x86_64, x86, mips64 and powerpc.
* math/bits/mathcalls.h [__GLIBC_USE (IEC_60559_BFP_EXT)]
(fromfp): New declaration.
[__GLIBC_USE (IEC_60559_BFP_EXT)] (fromfpx): Likewise.
[__GLIBC_USE (IEC_60559_BFP_EXT)] (ufromfp): Likewise.
[__GLIBC_USE (IEC_60559_BFP_EXT)] (ufromfpx): Likewise.
* math/tgmath.h (__TGMATH_TERNARY_FIRST_REAL_RET_ONLY): New macro.
[__GLIBC_USE (IEC_60559_BFP_EXT)] (fromfp): Likewise.
[__GLIBC_USE (IEC_60559_BFP_EXT)] (ufromfp): Likewise.
[__GLIBC_USE (IEC_60559_BFP_EXT)] (fromfpx): Likewise.
[__GLIBC_USE (IEC_60559_BFP_EXT)] (ufromfpx): Likewise.
* math/math.h: Include <bits/types.h>.
[__GLIBC_USE (IEC_60559_BFP_EXT)] (FP_INT_UPWARD): New enum
constant and macro.
(FP_INT_DOWNWARD): Likewise.
(FP_INT_TOWARDZERO): Likewise.
(FP_INT_TONEARESTFROMZERO): Likewise.
(FP_INT_TONEAREST): Likewise.
* math/Versions (fromfp): New libm symbol at version GLIBC_2.25.
(fromfpf): Likewise.
(fromfpl): Likewise.
(ufromfp): Likewise.
(ufromfpf): Likewise.
(ufromfpl): Likewise.
(fromfpx): Likewise.
(fromfpxf): Likewise.
(fromfpxl): Likewise.
(ufromfpx): Likewise.
(ufromfpxf): Likewise.
(ufromfpxl): Likewise.
* math/Makefile (libm-calls): Add s_fromfpF, s_ufromfpF,
s_fromfpxF and s_ufromfpxF.
* math/gen-fromfp-tests.py: New file.
* math/gen-fromfp-tests-inputs: Likewise.
* math/libm-test.inc: Include <stdint.h>
(check_intmax_t): New function.
(check_uintmax_t): Likewise.
(struct test_fiu_M_data): New type.
(struct test_fiu_U_data): Likewise.
(RUN_TEST_fiu_M): New macro.
(RUN_TEST_LOOP_fiu_M): Likewise.
(RUN_TEST_fiu_U): Likewise.
(RUN_TEST_LOOP_fiu_U): Likewise.
(fromfp_test_data): New array.
(fromfp_test): New function.
(fromfpx_test_data): New array.
(fromfpx_test): New function.
(ufromfp_test_data): New array.
(ufromfp_test): New function.
(ufromfpx_test_data): New array.
(ufromfpx_test): New function.
(main): Call fromfp_test, fromfpx_test, ufromfp_test and
ufromfpx_test.
* math/gen-libm-test.pl (parse_args): Handle u, M and U descriptor
characters.
* math/test-tgmath-ret.c: Include <stdint.h>.
(rm): New variable.
(width): Likewise.
(CHECK_RET_CONST_TYPE): Take extra arguments and pass them to
called function.
(CHECK_RET_CONST_FLOAT): Take extra arguments and pass them to
CHECK_RET_CONST_TYPE.
(CHECK_RET_CONST_DOUBLE): Likewise.
(CHECK_RET_CONST_LDOUBLE): Likewise.
(CHECK_RET_CONST): Take extra arguments and pass them to calls
macros.
(fromfp): New CHECK_RET_CONST call.
(ufromfp): Likewise.
(fromfpx): Likewise.
(ufromfpx): Likewise.
(do_test): Call check_return_fromfp, check_return_ufromfp,
check_return_fromfpx and check_return_ufromfpx.
* math/test-tgmath.c: Include <stdint.h>
(NCALLS): Increase to 138.
(F(compile_test)): Initialize i. Call fromfp functions.
(F(fromfp)): New function.
(F(fromfpx)): Likewise.
(F(ufromfp)): Likewise.
(F(ufromfpx)): Likewise.
* manual/arith.texi (Rounding Functions): Document FP_INT_UPWARD,
FP_INT_DOWNWARD, FP_INT_TOWARDZERO, FP_INT_TONEARESTFROMZERO,
FP_INT_TONEAREST, fromfp, fromfpf, fromfpl, ufromfp, ufromfpf,
ufromfpl, fromfpx, fromfpxf, fromfpxl, ufromfpx, ufromfpxf and
ufromfpxl.
* manual/libm-err-tab.pl (@all_functions): Add fromfp, fromfpx,
ufromfp and ufromfpx.
* math/fromfp.h: New file.
* sysdeps/ieee754/dbl-64/s_fromfp.c: Likewise.
* sysdeps/ieee754/dbl-64/s_fromfp_main.c: Likewise.
* sysdeps/ieee754/dbl-64/s_fromfpx.c: Likewise.
* sysdeps/ieee754/dbl-64/s_ufromfp.c: Likewise.
* sysdeps/ieee754/dbl-64/s_ufromfpx.c: Likewise.
* sysdeps/ieee754/flt-32/s_fromfpf.c: Likewise.
* sysdeps/ieee754/flt-32/s_fromfpf_main.c: Likewise.
* sysdeps/ieee754/flt-32/s_fromfpxf.c: Likewise.
* sysdeps/ieee754/flt-32/s_ufromfpf.c: Likewise.
* sysdeps/ieee754/flt-32/s_ufromfpxf.c: Likewise.
* sysdeps/ieee754/ldbl-128/s_fromfpl.c: Likewise.
* sysdeps/ieee754/ldbl-128/s_fromfpl_main.c: Likewise.
* sysdeps/ieee754/ldbl-128/s_fromfpxl.c: Likewise.
* sysdeps/ieee754/ldbl-128/s_ufromfpl.c: Likewise.
* sysdeps/ieee754/ldbl-128/s_ufromfpxl.c: Likewise.
* sysdeps/ieee754/ldbl-128ibm/s_fromfpl.c: Likewise.
* sysdeps/ieee754/ldbl-128ibm/s_fromfpl_main.c: Likewise.
* sysdeps/ieee754/ldbl-128ibm/s_fromfpxl.c: Likewise.
* sysdeps/ieee754/ldbl-128ibm/s_ufromfpl.c: Likewise.
* sysdeps/ieee754/ldbl-128ibm/s_ufromfpxl.c: Likewise.
* sysdeps/ieee754/ldbl-96/s_fromfpl.c: Likewise.
* sysdeps/ieee754/ldbl-96/s_fromfpl_main.c: Likewise.
* sysdeps/ieee754/ldbl-96/s_fromfpxl.c: Likewise.
* sysdeps/ieee754/ldbl-96/s_ufromfpl.c: Likewise.
* sysdeps/ieee754/ldbl-96/s_ufromfpxl.c: Likewise.
* sysdeps/ieee754/ldbl-opt/Makefile (libnldbl-calls): Add fromfp,
ufromfp, fromfpx and ufromfpx.
(CFLAGS-nldbl-fromfp.c): New variable.
(CFLAGS-nldbl-fromfpx.c): Likewise.
(CFLAGS-nldbl-ufromfp.c): Likewise.
(CFLAGS-nldbl-ufromfpx.c): Likewise.
* sysdeps/ieee754/ldbl-opt/nldbl-compat.h: Include <stdint.h>.
* sysdeps/ieee754/ldbl-opt/nldbl-fromfp.c: New file.
* sysdeps/ieee754/ldbl-opt/nldbl-fromfpx.c: Likewise.
* sysdeps/ieee754/ldbl-opt/nldbl-ufromfp.c: Likewise.
* sysdeps/ieee754/ldbl-opt/nldbl-ufromfpx.c: Likewise.
* sysdeps/nacl/libm.abilist: Update.
* sysdeps/unix/sysv/linux/aarch64/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/alpha/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/arm/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/hppa/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/i386/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/ia64/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/m68k/coldfire/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/m68k/m680x0/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/microblaze/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/mips/mips32/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/mips/mips64/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/nios2/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libm.abilist:
Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libm.abilist:
Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc64/libm-le.abilist:
Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc64/libm.abilist:
Likewise.
* sysdeps/unix/sysv/linux/s390/s390-32/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/s390/s390-64/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/sh/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/sparc/sparc32/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/sparc/sparc64/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libm.abilist:
Likewise.
* sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libm.abilist:
Likewise.
* sysdeps/unix/sysv/linux/tile/tilepro/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/x86_64/64/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/x86_64/x32/libm.abilist: Likewise.
Florian Weimer [Fri, 30 Dec 2016 17:43:04 +0000 (18:43 +0100)]
resolv: Turn historic name lookup functions into compat symbols
This change also removes the preprocessor-based function renaming.
It also applied to tests in resolv/, which ended up running against
the historic functions.
_endhtent was not part of the ABI because it is not listed in the
resolv/Versions file.
Joseph Myers [Fri, 30 Dec 2016 13:41:40 +0000 (13:41 +0000)]
Define __intmax_t, __uintmax_t in bits/types.h.
TS 18661-1 defines *fromfp* functions, which are declared in math.h
and whose return types are intmax_t and uintmax_t, without allowing
math.h to define those typedefs. (This is similar to e.g. ISO C
declaring vprintf in stdio.h without allowing that header to define
va_list.) Thus, math.h needs to access those typedefs under internal
names.
This patch accordingly arranges for bits/types.h (which defines only
internal names, not public *_t typedefs) to define __intmax_t and
__uintmax_t. stdint.h is made to use bits/types.h and define intmax_t
and uintmax_t using __intmax_t and __uintmax_t, to avoid duplication
of information. (It would be reasonable to define more of the types
in stdint.h - and in sys/types.h, where it duplicates such types -
using information already available in bits/types.h.) The idea is
that the subsequent addition of fromfp functions would then make
math.h include bits/types.h and use __intmax_t and __uintmax_t as the
return types of those functions.
Tested for x86_64 and x86 (testsuite, and that installed stripped
shared libraries are unchanged by the patch).
* bits/types.h (__intmax_t): New typedef.
(__uintmax_t): Likewise.
* sysdeps/generic/stdint.h: Include <bits/types.h>.
(intmax_t): Define using __intmax_t.
(uintmax_t): Define using __uintmax_t.
Joseph Myers [Fri, 30 Dec 2016 13:01:44 +0000 (13:01 +0000)]
Fix tst-support_record_failure-2 for run-built-tests = no.
The support/tst-support_record_failure-2.out test attempts to run
built code even if run-built-tests = no, so failing with
build-many-glibcs.py for all architectures whose code cannot be run on
the system running the script. This patch disables the test in that
case.
Tested for x86_64 (native), and for aarch64 with build-many-glibcs.py.
* support/Makefile (tests-special): Make definition conditional on
[$(run-built-tests) = yes].
($(objpfx)tst-support_record_failure-2.out): Make rule conditional
on [$(run-built-tests) = yes].
Mike Frysinger [Thu, 15 Dec 2016 23:34:05 +0000 (18:34 -0500)]
localedata: bs_BA: fix yesexpr/noexpr [BZ #20974]
Both regexes end with a "*." which means the previous match can be
omitted, and then the . allows them to match any input at all.
This means tools like coreutils' `rm -i` will always delete things
when prompted because the yesexpr regex matches all inputs (even
the negative ones).
Fix pretty printer tests for run-built-tests == no
In my change to add configure tests for python I had a brainfart where
I tried to filter out unsupported tests from tests-printers-programs
instead of tests-printers to select tests to build. I realize now
that all of that is completely unnecessary and it would be safe to
just build the tests as long as we don't try to run it.
This patch reverts that bit of the change. Tested with
run-built-tests = no in config.make.
* Rules (tests): Add tests-printers-programs to tests to be
built.
This patch adds a simple SYSV shared memory test to check for correct
argument passing on kernel. The idea is neither to be an extensive
testing nor to check for any specific Linux test.
* sysvipc/Makefile (tests): Add test-sysvshm.
* sysvipc/test-sysvshm.c: New file.
This patch consolidates the shmctl Linux implementation in only
one default file, sysdeps/unix/sysv/linux/shmctl.c. If tries to use
the direct syscall if it is supported, otherwise will use the old ipc
multiplex mechanism.
The patch also simplify header inclusion and reorganize internal
compat symbol to be built only if old ipc is defined.
Checked on x86_64, i686, powerpc64le, aarch64, and armhf.
This patch adds a simple SYSV semaphore test to check for correct
argument passing on kernel. The idea is neither to be an extensive
testing nor to check for any specific Linux test.
* sysvipc/Makefile (tests): Add test-sysvsem.
* sysvipc/test-sysvsem.c: New file.
This patch consolidates the semtimedop Linux implementation in only
one default file, sysdeps/unix/sysv/linux/semtimedop.c. If tries to use
the direct syscall if it is supported, otherwise will use the old ipc
multiplex mechanism.
Checked on x86_64, i686, powerpc64le, aarch64, and armhf.
* sysdeps/unix/sysv/linux/alpha/syscalls.list (semtimedop): Remove.
* sysdeps/unix/sysv/linux/arm/syscalls.list (semtimedop): Likewise.
* sysdeps/unix/sysv/linux/generic/syscalls.list (semtimedop):
Likewise.
* sysdeps/unix/sysv/linux/hppa/syscalls.list (semtimedop): Likewise.
* sysdeps/unix/sysv/linux/ia64/syscalls.list (semtimedop): Likewise.
* sysdeps/unix/sysv/linux/microblaze/syscalls.list (semtimedop):
Likewise.
* sysdeps/unix/sysv/linux/mips/mips64/syscalls.list (semtimedop):
Likewise.
* sysdeps/unix/sysv/linux/x86_64/syscalls.list (semtimedop): Likewise.
* sysdeps/unix/sysv/linux/m68k/semtimedop.S: Remove file.
* sysdeps/unix/sysv/linux/s390/semtimedop.c: Reorganize headers and
add a comment about s390 syscall difference from default one.
* sysdeps/unix/sysv/linux/semtimedop.c (semtimedop): Use semtimedop
syscall if it is defined.
This patch consolidates the semctl Linux implementation in only
one default file, sysdeps/unix/sysv/linux/semctl.c. If tries to use
the direct syscall if it is supported, otherwise will use the old ipc
multiplex mechanism.
The patch also simplify header inclusion and reorganize internal
compat symbol to be built only if old ipc is defined.
Checked on x86_64, i686, powerpc64le, aarch64, and armhf.
This patch adds a simple SYSV message queue test to check for correct
argument passing on kernel. The idea is neither to be an extensive
testing nor to check for any specific Linux test.
* sysvipc/Makefile (tests): Add test-sysvmsg.
* sysvipc/test-sysvmsg.c: New file.
* test-skeleton.c (FAIL_UNSUPPORTED): New define.
This patch consolidates the msgrcv Linux implementation in only
one default file, sysdeps/unix/sysv/linux/msgrcv.c. If tries to use
the direct syscall if it is supported, otherwise will use the old ipc
multiplex mechanism.
Checked on x86_64, i686, powerpc64le, aarch64, and armhf.
This patch consolidates the msgctl Linux implementation in only
one default file, sysdeps/unix/sysv/linux/msgctl.c. If tries to use
the direct syscall if it is supported, otherwise will use the old ipc
multiplex mechanism.
The patch also simplify header inclusion and reorganize internal
compat symbol to be built only if old ipc is defined.
Checked on x86_64, i686, powerpc64le, aarch64, and armhf.
Some architectures support the old-style IPC and require IPC_64 equal to
0x100 to be passed along SysV IPC syscalls, while new architectures should
default to new IPC version (without the flags being set).
This patch refactor current ipc_priv.h Linux headers in two directions:
- Remove cross platform references (for instance alpha including powerpc
definition) and add required definition for each required port. The
idea is to avoid tie one architecture definition with another and make
platform change independent.
- Move all common definitions (the ipc syscall commands) on a common
header, ipc_ops.h.
* sysdeps/unix/sysv/linux/aarch64/ipc_priv.h: New file.
* sysdeps/unix/sysv/linux/alpha/ipc_priv.h: Avoid included other arch
definition and define its own.
* sysdeps/unix/sysv/linux/ipc_ops.h: New file.
* sysdeps/unix/sysv/linux/x86_64/ipc_priv.h: Likewise.
* sysdeps/unix/sysv/linux/sparc/sparc64/ipc_priv.h: Likewise.
* sysdeps/unix/sysv/linux/mips/ipc_priv.h: Remove file.
* sysdeps/unix/sysv/linux/mips/mips64/ipc_priv.h: New file.
* sysdeps/unix/sysv/linux/ipc_priv.h: Move ipc syscall operation
definitions to common header.
* sysdeps/unix/sysv/linux/powerpc/ipc_priv.h: Use common syscall
operation from ipc_ops.h.
On current minimum supported kernels, the SysV IPC on Linux is provided
by either the ipc syscalls or correspondent wire syscalls. Also, for
architectures that supports wire syscalls all syscalls are supported
in a set (msgct, msgrcv, msgsnd, msgget, semctl, semget, semop, semtimedop,
shmctl, shmat, shmget, shmdt).
The architectures that only supports ipc syscall are:
- i386, m68k, microblaze, mips32, powerpc (powerpc32, powerpc64, and
powerpc64le), s390 (32 and 64 bits), sh, sparc32, and sparc64.
And the architectures that only supports wired syscalls are:
- aarch64, alpha, hppa, ia64, mips64, mips64n32, nios2, tile
(tilepro, tilegx, and tilegx64), and x86_64
Also arm is the only one that supports both wire syscalls and the
ipc, although the ipc one is deprecated.
This patch adds a new define, __ASSUME_DIRECT_SYSVIPC_SYSCALL, that wired
syscalls are supported on the system and the general idea is to use
it where possible.
I also checked the syscall table for all architectures on Linux 4.9
and there is no change on described support for Linux 2.6.32/3.2.
This patch adopts the same solution, with a minimal change: it
implements a saturated addition where overflows sets the maximum pointer
size to UINTPTR_MAX.
powerpc64: strchr/strchrnul optimization for power8
The P7 code is used for <=32B strings and for > 32B vectorized loops are used.
This shows as an average 25% improvement depending on the position of search
character. The performance is same for shorter strings.
Tested on ppc64 and ppc64le.
Florian Weimer [Wed, 28 Dec 2016 12:37:18 +0000 (13:37 +0100)]
support: Add support for delayed test failure reporting
The new functions support_record_failure records a test failure,
but does not terminate the process. The macros TEST_VERIFY
and TEST_VERIFY_EXIT check that a condition is true.
Current optimized memchr for x86_64 does for input arguments pointers
module 64 in range of [49,63] if there is no searchr char in the rest
of 64-byte block a pointer addition which might overflow:
Nick Alcock [Mon, 26 Dec 2016 09:09:06 +0000 (10:09 +0100)]
Do not stack-protect sigreturn stubs [BZ #7065]
These are called from the kernel with the stack at a carefully-
chosen location so that the stack frame can be restored: they must not
move the stack pointer lest garbage be restored into the registers.
We explicitly inhibit protection for SPARC and for signal/sigreturn.c:
other arches either define their sigreturn stubs in .S files, or (i386,
x86_64, mips) use macros expanding to top-level asm blocks and explicit
labels in the text section to mock up a "function" without telling the
compiler that one is there at all.
Nick Alcock [Mon, 26 Dec 2016 09:08:57 +0000 (10:08 +0100)]
PLT avoidance for __stack_chk_fail [BZ #7065]
Add a hidden __stack_chk_fail_local alias to libc.so,
and make sure that on targets which use __stack_chk_fail,
this does not introduce a local PLT reference into libc.so.
Nick Alcock [Mon, 26 Dec 2016 09:08:54 +0000 (10:08 +0100)]
Work even with compilers which enable -fstack-protector by default [BZ #7065]
With all the machinery we just added, we can easily arrange to work even
when the compiler passes in -fstack-protector automatically: all the
necessary bits of glibc are always compiled with -fno-stack-protector
now.
So tear out the check in configure, and add appropriate calls to
-fno-stack-protector in tests that need them (largely those that use
-nostdlib), since we don't yet have a __stack_chk_fail that those
tests can rely upon. (GCC often provides one, but we cannot rely on
this, especially not when bootstrapping.)
When stack protection is disabled, explicitly pass -fno-stack-protector
to everything, to stop a compiler hacked to enable it from inserting
calls to __stack_chk_fail via the PLT in every object file.
Nick Alcock [Mon, 26 Dec 2016 09:08:51 +0000 (10:08 +0100)]
Ignore __stack_chk_fail* in the rtld mapfile computation [BZ #7065]
The previous commit prevented rtld itself from being built with
-fstack-protector, but this is not quite enough. We identify which
objects belong in rtld via a test link and analysis of the resulting
mapfile. That link is necessarily done against objects that are
stack-protected, so drags in __stack_chk_fail_local, __stack_chk_fail,
and all the libc and libio code they use.
To stop this happening, use --defsym in the test librtld.map-production
link to force the linker to predefine these two symbols (to 0, but it
could be to anything). (In a real link, this would of course be
catastrophic, but these object files are never used for anything else.)
Nick Alcock [Mon, 26 Dec 2016 09:08:45 +0000 (10:08 +0100)]
Disable stack protector in early static initialization [BZ #7065]
The startup code in csu/, and the brk and sbrk functions are
needed very early in initialization of a statically-linked program,
before the stack guard is initialized; TLS initialization also uses
memcpy, which cannot overrun its own stack. Mark all of these as
-fno-stack-protector.
We also finally introduce @libc_cv_ssp@ and @no_stack_protector@, both
substituted by the configury changes made earlier, to detect the case
when -fno-stack-protector is supported by the compiler, and
unconditionally pass it in when this is the case, whether or not
--enable-stack-protector is passed to configure. (This means that
it'll even work when the compiler's been hacked to pass
-fstack-protector by default, unless the hackage is so broken that
it does so in a way that is impossible to override.)
Nick Alcock [Mon, 26 Dec 2016 09:08:41 +0000 (10:08 +0100)]
Do not stack-protect ifunc resolvers [BZ #7065]
When dynamically linking, ifunc resolvers are called before TLS is
initialized, so they cannot be safely stack-protected.
We avoid disabling stack-protection on large numbers of files by
using __attribute__ ((__optimize__ ("-fno-stack-protector")))
to turn it off just for the resolvers themselves. (We provide
the attribute even when statically linking, because we will later
use it elsewhere too.)
Nick Alcock [Mon, 26 Dec 2016 09:08:34 +0000 (10:08 +0100)]
Initialize the stack guard earlier when linking statically [BZ #7065]
The address of the stack canary is stored in a per-thread variable,
which means that we must ensure that the TLS area is intialized before
calling any -fstack-protector'ed functions. For dynamically linked
applications, we ensure this (in a later patch) by disabling
-fstack-protector for the whole dynamic linker, but for static
applications, the AT_ENTRY address is called directly by the kernel, so
we must deal with the problem differently.
In static appliations, __libc_setup_tls performs the TCB setup and TLS
initialization, so this commit arranges for it to be called early and
unconditionally. The call (and the stack guard initialization) is
before the DL_SYSDEP_OSCHECK hook, which if set will probably call
functions which are stack-protected (it does on Linux and NaCL too). We
also move apply_irel up, so that we can still safely call functions that
require ifuncs while in __libc_setup_tls (though if stack-protection is
enabled we still have to avoid calling functions that are not
stack-protected at this stage).