Yang Yingliang [Wed, 30 Apr 2014 10:16:18 +0000 (15:46 +0530)]
Fix lll_unlock twice in pthread_cond_broadcast
lll_unlock() will be called again if it goes to "wake_all" in
pthread_cond_broadcast(). This may make another thread which is
waiting for lock in pthread_cond_timedwait() unlock. So there are
more than one threads get the lock, it will break the shared data.
It's introduced by commit 8313cb997d2d("FUTEX_*_REQUEUE_PI support for
non-x86 code")
Initialize all of datahead structure in nscd (BZ #16791)
The datahead structure has an unused padding field that remains
uninitialized. Valgrind prints out a warning for it on querying a
netgroups entry. This is harmless, but is a potential data leak since
it would result in writing out an uninitialized byte to the cache
file. Besides, this happens only when there is a cache miss, so we're
not adding computation to any fast path.
Consolidate code to initialize nscd dataset header
This patch consolidates the code to initialize the header of a dataset
into a single set of functions (one for positive and another for
negative datasets) primarily to reduce repetition of code. The
secondary reason is to simplify Patch 2/2 which fixes the problem of
an uninitialized byte in the header by initializing an unused field in
the structure and hence preventing a possible data leak into the cache
file.
Do not fail if one of the two responses to AF_UNSPEC fails (BZ #14308)
[Fixes BZ #14308, #12994, #13651]
AF_UNSPEC results in sending two queries in parallel, one for the A
record and the other for the AAAA record. If one of these is a
referral, then the query fails, which is wrong. It should return at
least the one successful response.
The fix has two parts. The first part makes the referral fall back to
the SERVFAIL path, which results in using the successful response.
There is a bug in that path however, due to which the second part is
necessary. The bug here is that if the first response is a failure
and the second succeeds, __libc_res_nsearch does not detect that and
assumes a failure. The case where the first response is a success and
the second fails, works correctly.
This condition is produced by buggy routers, so here's a crude
interposable library that can simulate such a condition. The library
overrides the recvfrom syscall and modifies the header of the packet
received to reproduce this scenario. It has two key variables:
mod_packet and first_error.
The mod_packet variable when set to 0, results in odd packets being
modified to be a referral. When set to 1, even packets are modified
to be a referral.
The first_error causes the first response to be a failure so that a
domain-appended search is performed to test the second part of the
__libc_nsearch fix.
The driver for this fix is a simple getaddrinfo program that does an
AF_UNSPEC query. I have omitted this since it should be easy to
implement.
I have tested this on x86_64.
The interceptor library source:
/* Override recvfrom and modify the header of the first DNS response to make it
a referral and reproduce bz #845218. We have to resort to this ugly hack
because we cannot make bind return the buggy response of a referral for the
AAAA record and an authoritative response for the A record. */
#define _GNU_SOURCE
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <stdio.h>
#include <stdbool.h>
#include <endian.h>
#include <dlfcn.h>
#include <stdlib.h>
/* Lifted from resolv/arpa/nameser_compat.h. */
typedef struct {
unsigned id :16; /*%< query identification number */
#if BYTE_ORDER == BIG_ENDIAN
/* fields in third byte */
unsigned qr: 1; /*%< response flag */
unsigned opcode: 4; /*%< purpose of message */
unsigned aa: 1; /*%< authoritive answer */
unsigned tc: 1; /*%< truncated message */
unsigned rd: 1; /*%< recursion desired */
/* fields
* in
* fourth
* byte
* */
unsigned ra: 1; /*%< recursion available */
unsigned unused :1; /*%< unused bits (MBZ as of 4.9.3a3) */
unsigned ad: 1; /*%< authentic data from named */
unsigned cd: 1; /*%< checking disabled by resolver */
unsigned rcode :4; /*%< response code */
#endif
#if BYTE_ORDER == LITTLE_ENDIAN || BYTE_ORDER == PDP_ENDIAN
/* fields
* in
* third
* byte
* */
unsigned rd :1; /*%< recursion desired */
unsigned tc :1; /*%< truncated message */
unsigned aa :1; /*%< authoritive answer */
unsigned opcode :4; /*%< purpose of message */
unsigned qr :1; /*%< response flag */
/* fields
* in
* fourth
* byte
* */
unsigned rcode :4; /*%< response code */
unsigned cd: 1; /*%< checking disabled by resolver */
unsigned ad: 1; /*%< authentic data from named */
unsigned unused :1; /*%< unused bits (MBZ as of 4.9.3a3) */
unsigned ra :1; /*%< recursion available */
#endif
/* remaining
* bytes
* */
unsigned qdcount :16; /*%< number of question entries */
unsigned ancount :16; /*%< number of answer entries */
unsigned nscount :16; /*%< number of authority entries */
unsigned arcount :16; /*%< number of resource entries */
} HEADER;
static int done = 0;
/* Packets to modify. 0 for the odd packets and 1 for even packets. */
static const int mod_packet = 0;
/* Set to true if the first request should result in an error, resulting in a
search query. */
static bool first_error = true;
if (real_recvfrom == NULL)
{
printf ("Failed to get reference to recvfrom: %s\n", dlerror ());
printf ("Cannot simulate test\n");
abort ();
}
}
/* Modify the second packet that we receive to set the header in a manner as to
reproduce BZ #845218. */
static void
mod_buf (HEADER *h, int port)
{
if (done % 2 == mod_packet || (first_error && done == 1))
{
printf ("(Modifying header)");
Carlos O'Donell [Tue, 29 Apr 2014 17:31:05 +0000 (13:31 -0400)]
Remove ports README and update machine ChangeLogs.
This patch removes the ports/README now that ports is no longer
being used. It also adds a header to all ChangeLogs for all machines
that were moved to the main libc tree. The header indicates that the
ChangeLog is no longer used.
This patch optimizes the FPSCR update on exception and rounding change
functions by just updating its value if new value if different from
current one. It also optimizes fedisableexcept and feenableexcept by
removing an unecessary FPSCR read.
H.J. Lu [Fri, 25 Apr 2014 16:33:41 +0000 (09:33 -0700)]
Replace __int128 with __int128_t in bits/link.h
__int128 was added in GCC 4.6 and __int128_t was added before x86-64
was supported. This patch replaces __int128 with __int128_t so that
the installed bits/link.h can be used with older GCC.
* sysdeps/x86/bits/link.h (La_x86_64_regs): Replace __int128
with __int128_t.
(La_x86_64_retval): Likewise.
Carlos O'Donell [Thu, 17 Apr 2014 23:41:09 +0000 (19:41 -0400)]
manual: Sort overview listing by manual order.
In the glibc manual we have a "Roadmap to the manual" section at
the end of the "Introduction" chapter.
The introductory text says "Here is an overview of the contents
of the remaining chapters of this manual.", but then proceeds to
list chapters out of order and some chapter are never referenced.
This commit reorders the overview to correctly match the manual
order.
PowerPC: Sync pthread_once with default implementation
This patch removes the arch specific powerpc implementation and instead
uses the linux default one. Although the current powerpc implementation
already constains the required memory barriers for correct
initialization, the default implementation shows a better performance on
newer chips.
Will Newton [Thu, 13 Mar 2014 09:45:29 +0000 (09:45 +0000)]
manual/setjmp.texi: Clarify setcontext and signal handlers text
Calling setcontext from a signal handler can be done safely so
it is sufficient to note that it is not recommended.
Also mention in setcontext documentation that the behaviour of
setcontext when restoring a context created by a call to a signal
handler is unspecified.
2014-04-17 Will Newton <will.newton@linaro.org>
* manual/setjmp.texi (System V contexts): Add note that
calling setcontext on a context created by a call to a
signal handler is undefined. Update text to note that
setcontext from a signal handler is possible but not
recommended.
Will Newton [Tue, 25 Feb 2014 14:29:32 +0000 (14:29 +0000)]
stdlib/tst-setcontext.c: Check for clobbering of signal stack
On aarch64 calling swapcontext clobbers the state of the signal
stack (BZ #16629). Check that the address and size of the signal
stack before and after the call to swapcontext remains the same.
ChangeLog:
2014-04-17 Will Newton <will.newton@linaro.org>
[BZ #16629]
* stdlib/tst-setcontext.c: Include signal.h.
(main): Check that the signal stack before and
after swapcontext is the same.
Will Newton [Wed, 12 Mar 2014 16:14:51 +0000 (16:14 +0000)]
aarch64: Re-implement setcontext without rt_sigreturn syscall
The current implementation of setcontext uses rt_sigreturn to restore
the contents of registers. This contrasts with the way most other
architectures implement setcontext:
powerpc64, mips, tile:
Call rt_sigreturn if context was created by a call to a signal handler,
otherwise restore in user code.
powerpc32:
Call swapcontext system call and don't call sigreturn or rt_sigreturn.
x86_64, sparc, hppa, sh, ia64, m68k, s390, arm:
Only support restoring "synchronous" contexts, that is contexts
created by getcontext, and restoring in user code and don't call
sigreturn or rt_sigreturn.
alpha:
Call sigreturn (but not rt_sigreturn) in all cases to do the restore.
The text of the setcontext manpage suggests that the requirement to be
able to restore a signal handler created context has been dropped from
SUSv2:
If the context was obtained by a call to a signal handler, then old
standard text says that "program execution continues with the program
instruction following the instruction interrupted by the signal".
However, this sentence was removed in SUSv2, and the present verdict
is "the result is unspecified".
Implementing setcontext by calling rt_sigreturn unconditionally causes
problems when used with sigaltstack as in BZ #16629. On this basis it
seems that aarch64 is broken and that new ports should only support
restoring contexts created with getcontext and do not need to call
rt_sigreturn at all.
This patch re-implements the aarch64 setcontext function to restore
the context in user code in a similar manner to x86_64 and other ports.
ChangeLog:
2014-04-17 Will Newton <will.newton@linaro.org>
[BZ #16629]
* sysdeps/unix/sysv/linux/aarch64/setcontext.S (__setcontext):
Re-implement to restore registers in user code and avoid
rt_sigreturn system call.
Alan Modra [Wed, 16 Apr 2014 10:03:32 +0000 (19:33 +0930)]
Correct IBM long double frexpl.
Besides fixing the bugzilla, this also fixes corner-cases where the high
and low double differ greatly in magnitude, and handles a denormal
input without resorting to a fp rescale.
benchtests: Link against objects in build directory
Using -lm and -lpthread results in the shared objects in the system
being used to link against. This happened to work for libm because
there haven't been any changes to the libm ABI recently that could
break the existing benchmarks. This doesn't always work for the
pthread benchmarks. The correct way to build against libraries in the
build directory is to have the binaries explicitly depend on them so
that $(+link) can pick them up.
Carlos O'Donell [Fri, 11 Apr 2014 16:43:58 +0000 (12:43 -0400)]
Support _r_debug for static binaries.
We initialize _r_debug for static binaries to allows debug
agents to treat static binaries a little more like dyanmic
ones. This simplifies the work a debug agent has to do to
access TLS in a static binary via libthread_db.
Carlos O'Donell [Thu, 10 Apr 2014 22:31:53 +0000 (18:31 -0400)]
nscd: Make SELinux checks dynamic.
The SELinux team has indicated to me that glibc's SELinux checks
in nscd are not being carried out as they would expect the API
to be used today. They would like to move away from static header
defines for class and permissions and instead use dynamic checks
at runtime that provide an answer which is dependent on the runtime
status of SELinux i.e. more dynamic.
The following patch is a minimal change that moves us forward in
this direction.
It does the following:
* Stop checking for SELinux headers that define NSCD__SHMEMHOST.
Check only for the presence or absence of the library.
* Don't encode the specific SELinux permission constants into a
table at build time, and instead use the symbolic name for the
permission as expected.
* Lookup the "What do we do if we don't know this permission?"
policy and use that if we find SELinux's policy is older than
the glibc policy e.g. we make a request for a permission that
SELinux doesn't know about.
* Lastly, translate the class and permission and then make
the permission check. This is done every time we lookup
a permission, and this is the expected way to use the API.
SELinux will optimize this for us, and we expect the network
latencies to hide these extra library calls.
Tested on x86, x86-64, and via Fedora Rawhide since November 2013.
Will Newton [Tue, 8 Apr 2014 09:18:16 +0000 (10:18 +0100)]
benchtests: Improve readability of JSON output
Add a small library to print JSON values and use it to improve the
readability of the benchmark output and the readability of the
benchmark code.
ChangeLog:
2014-04-11 Will Newton <will.newton@linaro.org>
* benchtests/Makefile (extra-objs): Add json-lib.o.
(bench-func): Tidy up JSON output.
* benchtests/bench-skeleton.c: Include json-lib.h.
(main): Use JSON library functions to do output of
benchmark results.
* benchtests/bench-timing-type.c (main): Output the
timing type simply, leaving formatting to the user.
* benchtests/json-lib.c: New file.
* benchtests/json-lib.h: Likewise.
Torvald Riegel [Wed, 8 May 2013 14:35:10 +0000 (16:35 +0200)]
Fixed and unified pthread_once.
[BZ #15215] This unifies various pthread_once architecture-specific
implementations which were using the same algorithm with slightly different
implementations. It also adds missing memory barriers that are required for
correctness.
Will Newton [Mon, 31 Mar 2014 14:00:32 +0000 (15:00 +0100)]
malloc: Fix MALLOC_DEBUG -Wundef warning
MALLOC_DEBUG is set optionally on the command line. Default the value
to zero if it is not set on the command line, and test its value
with #if rather than #ifdef. Verified the code is identical before
and after this change apart from line numbers.
ChangeLog:
2014-04-11 Will Newton <will.newton@linaro.org>
* malloc/malloc.c [!MALLOC_DEBUG]: #define MALLOC_DEBUG
to zero if it is not defined elsewhere. (mtrim): Test
the value of MALLOC_DEBUG with #if rather than #ifdef.
Torvald Riegel [Tue, 8 Oct 2013 11:17:01 +0000 (14:17 +0300)]
benchtests: Add pthread_once common-case test.
We have a single thread that runs a no-op initialization once and then
repeatedly runs checks of the initialization (i.e., an acquire load and
conditional jump) in a tight loop. This gives us, on average, the
best-case latency of pthread_once (the initialization is the
exactly-once slow path, and we're not looking at initialization-related
synchronization overheads in this case).
Igor Zamyatin [Tue, 1 Apr 2014 17:16:04 +0000 (10:16 -0700)]
Save/restore bound registers in _dl_runtime_resolve
This patch saves and restores bound registers in symbol lookup for x86-64:
1. Branches without BND prefix clear bound registers.
2. x86-64 pass bounds in bound registers as specified in MPX psABI
extension on hjl/mpx/master branch at
This patch defines _STRING_ARCH_unaligned to 0 on default bits/string.h
header to avoid undefined compiler warnings on platforms that do not
define it. It also make adjustments in code where tests checked if macro
existed or not.
pathconf(_PC_NAME_MAX) was implemented on top of statfs(). The 32bit
version therefore fails EOVERFLOW if the filesystem blockcount is
sufficiently large.
Most pathconf() queries use statvfs64(), which avoids this issue. This
patch modifies pathconf(_PC_NAME_MAX) to do likewise.
Move __PTHREAD_SPINS definition to architecture specific header
This patch moves the __PTHREAD_SPINS definition to arch specific header
since pthread_mutex_t layout is also arch specific. This leads to no
need to defining __PTHREAD_MUTEX_HAVE_ELISION and thus removing of the
undefined compiler warning.
This patch fixes some powerpc32 and powerpc64 builds with
--disable-multi-arch option along with different --with-cpu=powerN.
It cleanups the Implies directories by removing the multiarch
folder for non multiarch config and also fixing two assembly
implementations: powerpc64/power7/strncat.S that is calling the
wrong strlen; and power8/fpu/s_isnan.S that misses the hidden_def and
weak_alias directives.
Will Newton [Mon, 31 Mar 2014 12:47:56 +0000 (13:47 +0100)]
string: Cosmetic cleanup of string functions
Clean up string functions that do not have a version in gnulib on
the assumption that glibc is the canonical upstream copy of this
code. basename has a copy in gnulib but it is largely written to
handle Windows paths so merging it is not really viable. The changes
mostly consist of switching to ANSI function prototypes and removing
unused includes.
As many of these functions do not get built in a typical build due
to architecture optimized versions being used instead I built these
by hand to verify there were no build warnings and the code was
identical.
2014-04-07 Will Newton <will.newton@linaro.org>
* string/basename.c [HAVE_CONFIG_H]: Remove #ifdef and
and contents. [!_LIBC] Remove #ifndef and contents.
(basename): Use ANSI prototype. [_LIBC] Remove #idef.
* string/memccpy.c (__memccpy): Use ANSI prototype.
* string/memfrob.c (memfrob): Likewise.
* string/strcoll.c (STRCOLL): Likewise.
* string/strlen.c (strlen): Likewise.
* string/strtok.c (STRTOK): Likewise.
* string/strcat.c: Remove unused #include of memcopy.h.
(strcat): Use ANSI prototype.
* string/strchr.c: Remove unused #include of memcopy.h.
(strchr): Use ANSI prototype.
* string/strcmp.c: Remove unused #include of memcopy.h.
(strcmp): Use ANSI prototype.
* string/strcpy.c: Remove unused #include of memcopy.h.
(strcpy): Use ANSI prototype.
This patch makes the configure adds -D_CALL_ELF=1 when compiler does
not define _CALL_ELF (versions before powerpc64le support). It cleans
up compiler warnings on old compiler where _CALL_ELF is not defined
on powerpc64(be) builds.
It does by add a new config.make variable for configure-deduced
CPPFLAGS and accumulate into that (confix-extra-cppflags). It also
generalizes libc_extra_cflags so it accumulates in sysdeps configure
fragmenets.
PowerPC: Fix nearbyint/nearbyintf result for FE_DOWNWARD
This patch fixes the powerpc32 optimized nearbyint/nearbyintf bogus
results for FE_DOWNWARD rounding mode. This is due wrong instructions
sequence used in the rounding calculation (two subtractions instead of
adition and a subtraction).
David Svoboda [Wed, 2 Apr 2014 09:13:02 +0000 (05:13 -0400)]
manual: clarify buffer behavior in getline [BZ #5666]
If the user has requested automatic buffer creation, getline may create
it and not free things when an error occurs. That means the user is
always responsible for calling free() regardless of the return value.
The current documentation does not explicitly cover this which leaves it
slightly ambiguous to the reader. So clarify things.
Will Newton [Wed, 2 Apr 2014 14:23:16 +0000 (15:23 +0100)]
elf/dl-lookup.c: Remove obsolete comment about nested function
The nested function referred to has gone away so remove the
comment. Also move the variable declaration down to where other
variables of a similar lifetime are declared for clarity.
2014-04-03 Will Newton <will.newton@linaro.org>
* elf/dl-lookup.c (do_lookup_x): Remove comment
referring to nested function and move variable
declarations down to before first use.
This patch fixes incorrect results from catan and catanh of certain
special inputs in round-downward mode (bug 16799), and incorrect
results of __ieee754_logf (+/-0) in round-downward mode (bug 16800)
that show up through catan/catanh when tested in all rounding modes,
but not directly in the testing for logf because the bug gets hidden
by the wrappers.
Both bugs involve a zero that should be +0 being -0 instead: one
computed as (1-x)*(1+x) in the catan/catanh case, and one as (x-x) in
the logf case. The fixes ensure positive zero is used. Testing of
catan and catanh in all rounding modes is duly enabled.
I expect there are various other bugs in special cases in __ieee754_*
functions that are normally hidden by the wrappers but would show up
for testing with -lieee (or in future with -fno-math-errno if we
replace -lieee and _LIB_VERSION with compile-time redirection to new
*_noerrno symbol names).
Tested x86_64 and x86 and ulps updated accordingly.
Joseph Myers [Wed, 2 Apr 2014 13:10:19 +0000 (13:10 +0000)]
Fix clog / clog10 sign of zero result in round-downward mode (bug 16789).
This patch fixes bug 16789, incorrect sign of (real part) zero result
from clog and clog10 in round-downward mode, arising from that real
part being computed as 0 - 0. To ensure that an underflow exception
occurred, the code used an underflowing value (the next term in the
series for log1p) in arithmetic computing the real part of the result,
yielding the problematic 0 - 0 computation in some cases even when the
mathematical result would be small but positive. The patch changes
this code to use the math_force_eval approach to ensuring that an
underflowing computation actually occurs. Tests of clog and clog10
are enabled in all rounding modes.
Tested x86_64 and x86 and ulps updated accordingly.
[BZ #16789]
* math/s_clog.c (__clog): Use math_force_eval to ensure underflow
instead of using underflowing value in computing result.
* math/s_clog10.c (__clog10): Likewise.
* math/s_clog10f.c (__clog10f): Likewise.
* math/s_clog10l.c (__clog10l): Likewise.
* math/s_clogf.c (__clogf): Likewise.
* math/s_clogl.c (__clogl): Likewise.
* math/libm-test.inc (clog_test): Use ALL_RM_TEST.
(clog10_test): Likewise.
* sysdeps/i386/fpu/libm-test-ulps: Update.
* sysdeps/x86_64/fpu/libm-test-ulps: Likewise.
Alan Modra [Wed, 2 Apr 2014 03:16:19 +0000 (13:46 +1030)]
Correct IBM long double nextafterl.
Fix for values near a power of two, and some tidies.
[BZ #16739]
* sysdeps/ieee754/ldbl-128ibm/s_nextafterl.c (__nextafterl): Correct
output when value is near a power of two. Use int64_t for lx and
remove casts. Use decimal rather than hex exponent constants.
Don't use long double multiplication when double will suffice.
* math/libm-test.inc (nextafter_test_data): Add tests.
* NEWS: Add 16739 and 16786 to bug list.
Florian Weimer [Mon, 24 Mar 2014 14:24:02 +0000 (15:24 +0100)]
Check for syscall error in the SETXID implementation in NPTL (bug 13347).
At this point, we can only abort the process because we have already
switched credentials on other threads. Returning an error would still
leave the process in an inconsistent state.
Joseph Myers [Mon, 31 Mar 2014 14:57:53 +0000 (14:57 +0000)]
Set errno for scalb errors (bug 6803, bug 6804).
This patch fixes the default mode of scalb to set errno (bugs 6803 and
6804).
Previously, the _LIB_VERSION == _SVID_ mode would set errno but only
in some relevant cases, and with various peculiarities (such as errno
setting when an exact infinity or zero result arises with an argument
to scalb being an infinity). This patch leaves this mode
bug-compatible, while making the default mode set errno in accordance
with normal practice (so an exact infinity from an infinite argument
is not an error, and nor is an exact zero result). gen-libm-test.pl
is taught new notation such as ERRNO_PLUS_OFLOW to facilitate writing
the tests of errno setting for underflow / overflow in libm-test.inc.
Note that bug 6803 also covers scalbn and scalbln, but this patch only
addresses the scalb parts of that bug (along with the whole of bug
6804).
Tested x86_64 and x86.
[BZ #6803]
[BZ #6804]
* math/w_scalb.c (__scalb): For non-SVID mode, check result and
set errno as appropriate.
* math/w_scalbf.c (__scalbf): Likewise.
* math/w_scalbl.c (__scalbl): Likewise.
* math/gen-libm-test.pl (parse_args): Handle ERRNO_PLUS_OFLOW,
ERRNO_MINUS_OFLOW, ERRNO_PLUS_UFLOW and ERRNO_MINUS_UFLOW.
* math/libm-test.inc (scalb_test_data): Add errno expectations.
Add more NaN tests.
Joseph Myers [Mon, 31 Mar 2014 14:56:37 +0000 (14:56 +0000)]
Set errno for atan2 underflow (bug 16349).
This patch fixes bug 16349, missing errno setting for atan2 underflow,
by adding appropriate checks to the existing wrappers. (As in other
cases, the __kernel_standard support for calling matherr is considered
to be for existing code expecting existing rules for what's considered
an error, even if those don't correspond to a general logical scheme
for what counts as what kind of error, so __set_errno calls are added
directly without any changes to __kernel_standard.)
Tested x86_64 and x86.
[BZ #16349]
* math/w_atan2.c: Include <errno.h>.
(__atan2): Set errno for result underflowing to zero.
* math/w_atan2f.c: Include <errno.h>.
(__atan2f): Set errno for result underflowing to zero.
* math/w_atan2l.c: Include <errno.h>.
(__atan2l): Set errno for result underflowing to zero.
* math/auto-libm-test-in: Don't allow missing errno for some atan2
tests.
* math/auto-libm-test-out: Regenerated.
Joseph Myers [Mon, 31 Mar 2014 12:55:18 +0000 (12:55 +0000)]
Correct robust mutex / PI futex kernel assumptions (bug 9894).
This patch continues fixing __ASSUME_* issues in preparation for
moving to a 2.6.32 minimum kernel version by addressing assumptions on
robust mutex and PI futex support availability. Those assumptions are
bug 9894, but to be clear this patch does not address all the issues
from that bug about wrong version assumptions, only those still
applicable for --enable-kernel=2.6.32 or later (with the expectation
that the move to that minimum kernel will obsolete the other parts of
the bug). The patch is independent of
<https://sourceware.org/ml/libc-alpha/2014-03/msg00585.html>, my other
pending-review patch preparing for the kernel version change; the two
together complete all the changes I believe are needed in preparation
regarding any macro in sysdeps/unix/sysv/linux/kernel-features.h that
would be affected by such a change. (I have not checked the
correctness of macros whose conditions are unaffected by such a
change, or macros only defined in other kernel-features.h files.)
As discussed in that bug, robust mutexes and PI futexes need
futex_atomic_cmpxchg_inatomic to be implemented, in addition to
certain syscalls needed for robust mutexes (and
architecture-independent kernel pieces for all the features in
question). That is, as I understand it, they need
futex_atomic_cmpxchg_inatomic to *work* (not return an ENOSYS error).
The issues identified in my analysis relate to ARM, M68K, MicroBlaze,
MIPS and SPARC.
On ARM, whether futex_atomic_cmpxchg_inatomic works depends on the
kernel configuration. As of 3.13, the condition for *not* working is
CONFIG_CPU_USE_DOMAINS && CONFIG_SMP. As of 2.6.32 it was simply
CONFIG_SMP that meant the feature was not implemented. I don't know
if there are any circumstances in which we can say "we can assume a
userspace glibc binary built with these options will never run on a
kernel with the problematic configuration", but at least for now I'm
just undefining the relevant __ASSUME_* macros for ARM.
On M68K, two of the three macros are undefined for kernels before
3.10, but as far as I can see __ASSUME_FUTEX_LOCK_PI is in the same
group needing futex_atomic_cmpxchg_inatomic support and so should be
undefined as well.
On MicroBlaze the required support was added in 2.6.33.
On MIPS, the support depends on cpu_has_llsc in the kernel - that is,
actual hardware LL/SC support (GCC and glibc for MIPS GNU/Linux rely
on the instructions being supported in some way, but it may be kernel
emulation; futex_atomic_cmpxchg_inatomic doesn't work with that
emulation). The same condition as in GCC for indicating LL/SC support
may not be available is used for undefining the macros in glibc,
__mips == 1 || defined _MIPS_ARCH_R5900. (Maybe we could in fact
desupport MIPS processors without the hardware support in glibc.)
On SPARC, 32-bit kernels don't support futex_atomic_cmpxchg_inatomic;
__arch64__ || __sparc_v9__ is used as the condition for binaries that
won't run on 32-bit kernels.
This patch is not tested beyond the sanity check of an x86_64 build.
Joseph Myers [Mon, 31 Mar 2014 12:51:45 +0000 (12:51 +0000)]
Fix futimesat for older MicroBlaze kernels (bug 16648).
Continuing the fixes for __ASSUME_* issues in preparation for moving
to a 2.6.32 minimum kernel version, this *untested* patch fixes bug
16648, the definition of __ASSUME_ATFCTS meaning that the futimesat
syscall is assumed for all MicroBlaze kernels despite not being
present until 2.6.33.
__ASSUME_ATFCTS controls conditionals relating to a lot of different
syscalls in Linux-specific code (fstatat64 faccessat fchmodat fchownat
futimesat newfstatat linkat mkdirat openat readlinkat renameat
symlinkat unlinkat mknodat), where whether newfstatat fstatat64
futimesat are used depends on the architecture, as well as controlling
whether openat64_not_cancel_3 is expected to work in
sysdeps/posix/getcwd.c. The assumptions are all OK as of 2.6.32
except for this MicroBlaze case, and it's generally desirable to get
rid of as many of the __ASSUME_ATFCTS conditionals as possible, to
simplify the code (the fallbacks include potential unbounded dynamic
stack allocations). Thus, rather than the simplest approach of
undefining __ASSUME_ATFCTS for older kernels on MicroBlaze, this patch
takes the approach of using the linux-generic implementation of
futimesat for MicroBlaze kernels before 2.6.33 (all such kernels have
the utimensat syscall).
This patch fixes bug 16770, spurious "invalid" exceptions from scalb
when testing whether the second argument is an integer, by inserting
appropriate range checks to determine whether a cast to int is safe.
(Note that invalid_fn is a function that handles both nonintegers and
large integers, distinguishing them reliably using functions such as
__rint; note also that there are no issues with scalb needing to avoid
spurious "inexact" exceptions - it's an old-POSIX XSI function, not a
standard C function bound to an IEEE 754 operation - although the
return value is still fully determined.)
Tested x86_64 and x86.
[BZ #16770]
* math/e_scalb.c (__ieee754_scalb): Check second argument is not
too large before casting to int.
* math/e_scalbf.c (__ieee754_scalbf): Likewise.
* math/e_scalbl.c (__ieee754_scalbl): Likewise.
* math/libm-test.inc (scalb_test_data): Add more tests.
This patch adds an option to get detailed benchmark output for
functions. Invoking the benchmark with 'make DETAILED=1 bench' causes
each benchmark program to store a mean execution time for each input
it works on. This is useful to give a more comprehensive picture of
performance of functions compared to just the single mean figure.
This patch changes the output format of the main benchmark output file
(bench.out) to an extensible format. I chose JSON over XML because in
addition to being extensible, it is also not too verbose.
Additionally it has good support in python.
The significant change I have made in terms of functionality is to put
timing information as an attribute in JSON instead of a string and to
do that, there is a separate program that prints out a JSON snippet
mentioning the type of timing (hp_timing or clock_gettime). The mean
timing has now changed from iterations per unit to actual timing per
iteration.
Joseph Myers [Fri, 28 Mar 2014 20:53:32 +0000 (20:53 +0000)]
Fix clog10 (-0 +/- 0i) (bug 16362).
This patch fixes the imaginary part of clog10 (-0 +/- 0i), which
should be +/-pi / log(10) by analogy with clog (the functions were
wrongly returning a result with imaginary part +/-pi, same as for
clog, and the tests matched the incorrect result, though both
functions and tests were correct for the similar case of clog10 (-inf
+/- 0i)). Tested x86_64 and x86.
[BZ #16362]
* math/s_clog10.c (M_PI_LOG10E): New macro.
(__clog10): Use M_PI_LOG10E instead of M_PI when real and
imaginary parts are 0.
* math/s_clog10f.c (M_PI_LOG10Ef): New macro.
(__clog10f): Use M_PI_LOG10Ef instead of M_PI when real and
imaginary parts are 0.
* math/s_clog10l.c (M_PI_LOG10El): New macro.
(__clog10l): Use M_PI_LOG10El instead of M_PIl when real and
imaginary parts are 0.
* math/libm-test.inc (clog10_test_data): Update expected results
for when real and imaginary parts are 0.