This patch defines __libc_tbegin, __libc_tend, __libc_tabort and
__libc_tx_nesting_depth in htm.h which replaces the direct usage of
equivalent gcc builtins.
We have to use an own inline assembly instead of __builtin_tbegin,
as tbegin has to filter program interruptions which can't be done with
the builtin. Before this change, e.g. a segmentation fault within a
transaction, leads to a coredump where the instruction pointer points
behind the tbegin instruction instead of real failing one.
Now the transaction aborts and the code should be reexecuted by the
fallback path without transactions. The segmentation fault will
produce a coredump with the real failing instruction.
The fpc is not saved before starting the transaction. If e.g. the
rounging mode is changed and the transaction is aborting afterwards,
the builtin will not restore the fpc. This is now done with the
__libc_tbegin macro.
Now the call saved fprs have to be saved / restored in the
__libc_tbegin macro. Using the gcc builtin had forced the saving /
restoring of fprs at begin / end of e.g. __lll_lock_elision function.
The new macro saves these fprs before tbegin instruction and only
restores them on a transaction abort. Restoring is not needed on
a successfully started transaction.
The used inline assembly does not clobber the fprs / vrs!
Clobbering the latter ones would force the compiler to save / restore
the call saved fprs as those overlap with the vrs, but they only
need to be restored if the transaction fails. Thus the user of the
tbegin macros has to compile the file / function with -msoft-float.
It prevents gcc from using fprs / vrs.
ChangeLog:
* sysdeps/unix/sysv/linux/s390/Makefile (elision-CFLAGS):
Add -msoft-float.
* sysdeps/unix/sysv/linux/s390/htm.h: New File.
* sysdeps/unix/sysv/linux/s390/elision-lock.c:
Use __libc_t* transaction macros instead of __builtin_t*.
* sysdeps/unix/sysv/linux/s390/elision-trylock.c: Likewise.
* sysdeps/unix/sysv/linux/s390/elision-unlock.c: Likewise.
This uses atomic operations to access lock elision metadata that is accessed
concurrently (ie, adapt_count fields). The size of the data is less than a
word but accessed only with atomic loads and stores.
See also x86 commit ca6e601a9d:
"Use C11-like atomics instead of plain memory accesses in x86 lock elision."
ChangeLog:
* sysdeps/unix/sysv/linux/s390/elision-lock.c
(__lll_lock_elision): Use atomics to load / store adapt_count.
* sysdeps/unix/sysv/linux/s390/elision-trylock.c
(__lll_trylock_elision): Likewise.
Patch disables Intel TSX on some Haswell processors to avoid TSX
on kernels that weren't updated with the latest microcode package
(which disables broken feature by default).
* sysdeps/x86/cpu-features.c (get_common_indeces): Add
stepping identification.
(init_cpu_features): Add handle of Haswell.
explicit_bzero(s, n) is the same as memset(s, 0, n), except that the
compiler is not allowed to delete a call to explicit_bzero even if the
memory pointed to by 's' is dead after the call. Right now, this effect
is achieved externally by having explicit_bzero be a function whose
semantics are unknown to the compiler, and internally, with a no-op
asm statement that clobbers memory. This does mean that small
explicit_bzero operations cannot be expanded inline as small memset
operations can, but on the other hand, small memset operations do get
deleted by the compiler. Hopefully full compiler support for
explicit_bzero will happen relatively soon.
There are two new tests: test-explicit_bzero.c verifies the
visible semantics in the same way as the existing test-bzero.c,
and tst-xbzero-opt.c verifies the not-being-optimized-out property.
The latter is conceptually based on a test written by Matthew Dempsky
for the OpenBSD regression suite.
The crypt() implementation has an immediate use for this new feature.
We avoid having to add a GLIBC_PRIVATE alias for explicit_bzero
by running all of libcrypt's calls through the fortified variant,
__explicit_bzero_chk, which is in the impl namespace anyway. Currently
I'm not aware of anything in libc proper that needs this, but the
glue is all in place if it does become necessary. The legacy DES
implementation wasn't bothering to clear its buffers, so I added that,
mostly for consistency's sake.
* string/explicit_bzero.c: New routine.
* string/test-explicit_bzero.c, string/tst-xbzero-opt.c: New tests.
* string/Makefile (routines, strop-tests, tests): Add them.
* string/test-memset.c: Add ifdeffage for testing explicit_bzero.
* string/string.h [__USE_MISC]: Declare explicit_bzero.
* debug/explicit_bzero_chk.c: New routine.
* debug/Makefile (routines): Add it.
* debug/tst-chk1.c: Test fortification of explicit_bzero.
* string/bits/string3.h: Fortify explicit_bzero.
* manual/string.texi: Document explicit_bzero.
* NEWS: Mention addition of explicit_bzero.
* crypt/crypt-entry.c (__crypt_r): Clear key-dependent intermediate
data before returning, using explicit_bzero.
* crypt/md5-crypt.c (__md5_crypt_r): Likewise.
* crypt/sha256-crypt.c (__sha256_crypt_r): Likewise.
* crypt/sha512-crypt.c (__sha512_crypt_r): Likewise.
* include/string.h: Redirect internal uses of explicit_bzero
to __explicit_bzero_chk[_internal].
* string/Versions [GLIBC_2.25]: Add explicit_bzero.
* debug/Versions [GLIBC_2.25]: Add __explicit_bzero_chk.
* sysdeps/arm/nacl/libc.abilist
* sysdeps/unix/sysv/linux/aarch64/libc.abilist
* sysdeps/unix/sysv/linux/alpha/libc.abilist
* sysdeps/unix/sysv/linux/arm/libc.abilist
* sysdeps/unix/sysv/linux/hppa/libc.abilist
* sysdeps/unix/sysv/linux/i386/libc.abilist
* sysdeps/unix/sysv/linux/ia64/libc.abilist
* sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist
* sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist
* sysdeps/unix/sysv/linux/microblaze/libc.abilist
* sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist
* sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist
* sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist
* sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist
* sysdeps/unix/sysv/linux/nios2/libc.abilist
* sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist
* sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist
* sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist
* sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist
* sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist
* sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist
* sysdeps/unix/sysv/linux/sh/libc.abilist
* sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist
* sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist
* sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libc.abilist
* sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist
* sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist
* sysdeps/unix/sysv/linux/x86_64/64/libc.abilist
* sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist:
Add entries for explicit_bzero and __explicit_bzero_chk.
Current optimized powercp64/power7 memchr uses a strategy to check for
p versus align(p+n) (where 'p' is the input char pointer and n the
maximum size to check for the byte) without taking care for possible
overflow on the pointer addition in case of large 'n'.
It was triggered by 3038145ca2 where default rawmemchr (used to
created ppc64 rawmemchr in ifunc selection) now uses memchr (p, c, (size_t)-1)
on its implementation.
This patch fixes it by implement a satured addition where overflows
sets the maximum pointer size to UINTPTR_MAX.
Checked on powerpc64le-linux-gnu.
[BZ# 20971]
* sysdeps/powerpc/powerpc64/power7/memchr.S (__memchr): Avoid
overflow in pointer addition.
* string/test-memchr.c (do_test): Add an argument to pass as
the size on memchr.
(test_main): Add check for SIZE_MAX.
This patch converts the wrapper scalbln (which set errno directly
rather than doing anything with __kernel_standard) to use the
type-generic template machinery, in the same way that has been done
for ldexp.
Tested for powerpc64le, s390, and x86_64.
Various fmax and fmin function implementations mishandle sNaN
arguments:
(a) When both arguments are NaNs, the return value should be a qNaN,
but sometimes it is an sNaN if at least one argument is an sNaN.
(b) Under TS 18661-1 semantics, if either argument is an sNaN then the
result should be a qNaN (whereas if one argument is a qNaN and the
other is not a NaN, the result should be the non-NaN argument).
Various implementations treat sNaNs like qNaNs here.
This patch fixes the x86 and x86_64 versions (ignoring float and
double for 32-bit x86 given the inability to reliably avoid the sNaN
turning into a qNaN before it gets to the called function). Tests of
sNaN inputs to these functions are added.
Note on architecture versions I haven't changed for this issue:
AArch64 already gets this right (it uses a hardware instruction with
the correct semantics for both quiet and signaling NaNs) and does not
need changes. It's possible Alpha, IA64, SPARC might need changes
(this would be shown by the testsuite if so).
Tested for x86_64 and x86 (both i686 and i586 builds, to cover the
different x86 implementations).
[BZ #20947]
* sysdeps/i386/fpu/s_fmaxl.S (__fmaxl): Add the arguments when
either is a signaling NaN.
* sysdeps/i386/fpu/s_fminl.S (__fminl): Likewise. Make code
follow fmaxl more closely.
* sysdeps/i386/i686/fpu/s_fmaxl.S (__fmaxl): Add the arguments
when either is a signaling NaN.
* sysdeps/i386/i686/fpu/s_fminl.S (__fminl): Likewise.
* sysdeps/x86_64/fpu/s_fmax.S (__fmax): Likewise.
* sysdeps/x86_64/fpu/s_fmaxf.S (__fmaxf): Likewise.
* sysdeps/x86_64/fpu/s_fmaxl.S (__fmaxl): Likewise.
* sysdeps/x86_64/fpu/s_fmin.S (__fmin): Likewise.
* sysdeps/x86_64/fpu/s_fminf.S (__fminf): Likewise.
* sysdeps/x86_64/fpu/s_fminl.S (__fminl): Likewise.
* math/libm-test.inc (fmax_test_data): Add tests of sNaN inputs.
(fmin_test_data): Likewise.
Various fmax and fmin function implementations mishandle sNaN
arguments:
(a) When both arguments are NaNs, the return value should be a qNaN,
but sometimes it is an sNaN if at least one argument is an sNaN.
(b) Under TS 18661-1 semantics, if either argument is an sNaN then the
result should be a qNaN (whereas if one argument is a qNaN and the
other is not a NaN, the result should be the non-NaN argument).
Various implementations treat sNaNs like qNaNs here.
This patch fixes the powerpc versions of these functions (shared by
float and double, 32-bit and 64-bit). The structure of those versions
is that all ordered cases are already handled before anything dealing
with the case where the arguments are unordered; thus, this patch
causes no change to the code executed in the common case (neither
argument a NaN).
Tested for powerpc (32-bit and 64-bit), together with tests to be
added along with the x86_64 / x86 fixes.
[BZ #20947]
* sysdeps/powerpc/fpu/s_fmax.S (__fmax): Add the arguments when
either is a signaling NaN.
* sysdeps/powerpc/fpu/s_fmin.S (__fmin): Likewise.
Information about whether the ABI of long double is the same as that
of double is split between bits/mathdef.h and bits/wordsize.h.
When the ABIs are the same, bits/mathdef.h defines
__NO_LONG_DOUBLE_MATH. In addition, in the case where the same glibc
binary supports both -mlong-double-64 and -mlong-double-128,
bits/wordsize.h defines __LONG_DOUBLE_MATH_OPTIONAL, along with
__NO_LONG_DOUBLE_MATH if this particular compilation is with
-mlong-double-64.
As part of the refactoring I proposed in
<https://sourceware.org/ml/libc-alpha/2016-11/msg00745.html>, this
patch puts all that information in a single header,
bits/long-double.h. It is included from sys/cdefs.h alongside the
include of bits/wordsize.h, so other headers generally do not need to
include bits/long-double.h directly.
Previously, various bits/mathdef.h headers and bits/wordsize.h headers
had this long double information (including implicitly in some
bits/mathdef.h headers through not having the defines present in the
default version). After the patch, it's all in six bits/long-double.h
headers. Furthermore, most of those new headers are not
architecture-specific. Architectures with optional long double all
use the ldbl-opt sysdeps directory, either in the order (ldbl-64-128,
ldbl-opt, ldbl-128) or (ldbl-128ibm, ldbl-opt). Thus a generic header
for the case where long double = double, and headers in ldbl-128,
ldbl-96 and ldbl-opt, suffices to cover every architecture except for
cases where long double properties vary between different ABIs sharing
a set of installed headers; fortunately all the ldbl-opt cases share a
single compiler-predefined macro __LONG_DOUBLE_128__ that can be used
to tell whether this compilation is -mlong-double-64 or
-mlong-double-128.
The two cases where a set of headers is shared between ABIs with
different long double properties, MIPS (o32 has long double = double,
other ABIs use ldbl-128) and SPARC (32-bit has optional long double,
64-bit has required long double), need their own bits/long-double.h
headers.
As with bits/wordsize.h, multiple-include protection for this header
is generally implicit through the include guards on sys/cdefs.h, and
multiple inclusion is harmless in any case. There is one subtlety:
the header must not define __LONG_DOUBLE_MATH_OPTIONAL if
__NO_LONG_DOUBLE_MATH was defined before its inclusion, because doing
so breaks how sysdeps/ieee754/ldbl-opt/nldbl-compat.h defines
__NO_LONG_DOUBLE_MATH itself before including system headers. Subject
to keeping that working, it would be reasonable to move these macros
from defined/undefined #ifdef to always-defined 1/0 #if semantics, but
this patch does not attempt to do so, just rearranges where the macros
are defined.
After this patch, the only use of bits/mathdef.h is the alpha one for
modifying complex function ABIs for old GCC. Thus, all versions of
the header other than the default and alpha versions are removed, as
is the include from math.h.
Tested for x86_64 and x86. Also did compilation-only testing with
build-many-glibcs.py.
* bits/long-double.h: New file.
* sysdeps/ieee754/ldbl-128/bits/long-double.h: Likewise.
* sysdeps/ieee754/ldbl-96/bits/long-double.h: Likewise.
* sysdeps/ieee754/ldbl-opt/bits/long-double.h: Likewise.
* sysdeps/mips/bits/long-double.h: Likewise.
* sysdeps/unix/sysv/linux/sparc/bits/long-double.h: Likewise.
* math/Makefile (headers): Add bits/long-double.h.
* misc/sys/cdefs.h: Include <bits/long-double.h>.
* stdlib/strtold.c: Include <bits/long-double.h> instead of
<bits/wordsize.h>.
* bits/mathdef.h [!_COMPLEX_H]: Do not allow inclusion.
[!__NO_LONG_DOUBLE_MATH]: Remove conditional code.
* math/math.h: Do not include <bits/mathdef.h>.
* sysdeps/aarch64/bits/mathdef.h: Remove file.
* sysdeps/alpha/bits/mathdef.h [!_COMPLEX_H]: Do not allow
inclusion.
* sysdeps/ia64/bits/mathdef.h: Remove file.
* sysdeps/m68k/m680x0/bits/mathdef.h: Likewise.
* sysdeps/mips/bits/mathdef.h: Likewise.
* sysdeps/powerpc/bits/mathdef.h: Likewise.
* sysdeps/s390/bits/mathdef.h: Likewise.
* sysdeps/sparc/bits/mathdef.h: Likewise.
* sysdeps/x86/bits/mathdef.h: Likewise.
* sysdeps/s390/s390-32/bits/wordsize.h
[!__NO_LONG_DOUBLE_MATH && !__LONG_DOUBLE_MATH_OPTIONAL]: Remove
conditional code.
* sysdeps/s390/s390-64/bits/wordsize.h
[!__NO_LONG_DOUBLE_MATH && !__LONG_DOUBLE_MATH_OPTIONAL]:
Likewise.
* sysdeps/unix/sysv/linux/alpha/bits/wordsize.h
[!__NO_LONG_DOUBLE_MATH && !__LONG_DOUBLE_MATH_OPTIONAL]:
Likewise.
* sysdeps/unix/sysv/linux/powerpc/bits/wordsize.h
[!__NO_LONG_DOUBLE_MATH && !__LONG_DOUBLE_MATH_OPTIONAL]:
Likewise.
* sysdeps/unix/sysv/linux/sparc/bits/wordsize.h
[!__NO_LONG_DOUBLE_MATH && !__LONG_DOUBLE_MATH_OPTIONAL]:
Likewise.
This patch makes bits/fcntl-linux.h include <linux/falloc.h> to define
the FALLOC_* flags under __USE_GNU (linux/falloc.h defines only those
bits, nothing else).
Tested for x86_64 and x86.
* sysdeps/unix/sysv/linux/bits/fcntl-linux.h [__USE_GNU]: Include
<linux/falloc.h>.
(FALLOC_FL_KEEP_SIZE): Remove.
(FALLOC_FL_PUNCH_HOLE): Likewise.
(FALLOC_FL_COLLAPSE_RANGE): Likewise.
(FALLOC_FL_ZERO_RANGE): Likewise.
This patch consolidates the Linux renameat implementation on
sysdeps/unix/sysv/linux/renameat.c. The renameat syscall was
deprecated at b0da6d44 for newer architectures, so using the
auto-generation list may generate wrappers that returns ENOSYS.
Current code try to use __NR_renameat and if it is not define
it uses __NR_renameat2.
Checked on x86_64 and aarch64.
* sysdeps/unix/sysv/linux/renameat.c: New file.
* sysdeps/unix/sysv/linux/syscalls.list: Remove renameat.
This patch consolidates the Linux rename implementation on
sysdeps/unix/sysv/linux/rename.c. Current code try to use
__NR_rename if is defined and apply the same strategy for
__NR_renameat and __NR_renameat2.
Check on x86_64 and aarch64.
* sysdeps/unix/sysv/linux/rename.c: New file.
* sysdeps/unix/sysv/linux/generic/rename.c: Remove file.
This patch converts the wrapper log1p (which set errno directly rather
than doing anything with __kernel_standard) to use the type-generic
template machinery, in the same way that has been done for ilogb.
Tested for powerpc64le, s390, and x86_64.
The new test driver in <support/test-driver.c> has feature parity with
the old one. The main difference is that its hooking mechanism is
based on functions and function pointers instead of macros. This
commit also implements a new environment variable, TEST_COREDUMPS,
which disables the code which disables coredumps (that is, it enables
them if the invocation environment has not disabled them).
<test-skeleton.c> defines wrapper functions so that it is possible to
use existing macros with the new-style hook functionality.
This commit changes only a few test cases to the new test driver, to
make sure that it works as expected.
TS 18661-1 generally defines libm functions taking sNaN arguments to
return qNaN and raise "invalid", even for the cases where a
corresponding qNaN argument would not result in a qNaN return. This
includes hypot with one argument being an infinity and the other being
an sNaN. This patch duly fixes hypot implementatations in glibc
(generic and powerpc) to ensure qNaN, computed by arithmetic on the
arguments, is returned in that case.
Various implementations do their checks for infinities and NaNs inline
by manipulating the representations of the arguments. For simplicity,
this patch just uses issignaling to check for sNaN arguments. This
could be inlined like the existing code (with due care about reversed
quiet NaN conventions, for implementations where that is relevant),
but given that all these checks are in cases where it's already known
at least one argument is not finite, which should be the uncommon
case, that doesn't seem worthwhile unless performance issues are
observed in practice.
Tested for x86_64, x86, mips64 and powerpc.
[BZ #20940]
* sysdeps/ieee754/dbl-64/e_hypot.c (__ieee754_hypot): Do not
return Inf for arguments Inf and sNaN.
* sysdeps/ieee754/flt-32/e_hypotf.c (__ieee754_hypotf): Likewise.
* sysdeps/ieee754/ldbl-128/e_hypotl.c (__ieee754_hypotl):
Likewise.
* sysdeps/ieee754/ldbl-128ibm/e_hypotl.c (__ieee754_hypotl):
Likewise.
* sysdeps/ieee754/ldbl-96/e_hypotl.c (__ieee754_hypotl): Likewise.
* sysdeps/powerpc/fpu/e_hypot.c (TEST_INF_NAN): Do not return Inf
for arguments Inf and sNaN. When returning a NaN, compute it by
arithmetic on the arguments.
* sysdeps/powerpc/fpu/e_hypotf.c (TEST_INF_NAN): Likewise.
* math/libm-test.inc (pow_test_data): Add tests of sNaN arguments.
The x86_64/x86 powl implementations mishandle sNaN arguments, both by
returning sNaN in some cases (instead of doing arithmetic on the
arguments to produce the result when NaN arguments result in NaN
results) and by treating sNaN the same as qNaN for arguments (1, sNaN)
and (sNaN, 0), contrary to TS 18661-1 which requires those cases to
return qNaN instead of 1.
This patch makes the x86_64/x86 powl implementations follow TS 18661-1
semantics for sNaN arguments; sNaN tests are also added for pow.
Given the problems with testing float and double sNaN arguments on
32-bit x86 (sNaN tests disabled because the compiler may convert
unnecessarily to a qNaN when passing arguments), no changes are made
to the powf and pow implementations there.
Tested for x86_64 and x86.
[BZ #20916]
* sysdeps/i386/fpu/e_powl.S (__ieee754_powl): Do not return 1 for
arguments (sNaN, 0) or (1, sNaN). Do arithmetic on NaN arguments
to compute result.
* sysdeps/x86_64/fpu/e_powl.S (__ieee754_powl): Likewise.
* math/libm-test.inc (pow_test_data): Add tests of sNaN arguments.
This uses atomic operations to access lock elision metadata that is accessed
concurrently (ie, adapt_count fields). The size of the data is less than a
word but accessed only with atomic loads and stores; therefore, we add
support for shorter-size atomic load and stores too.
* include/atomic.h (__atomic_check_size_ls): New.
(atomic_load_relaxed, atomic_load_acquire, atomic_store_relaxed,
atomic_store_release): Use it.
* sysdeps/x86/elide.h (ACCESS_ONCE): Remove.
(elision_adapt, ELIDE_LOCK): Use atomics.
* sysdeps/unix/sysv/linux/x86/elision-lock.c (__lll_lock_elision): Use
atomics and improve code comments.
* sysdeps/unix/sysv/linux/x86/elision-trylock.c
(__lll_trylock_elision): Likewise.
Various pow function implementations mishandle sNaN arguments in
various ways. This includes returning sNaN instead of qNaN for sNaN
arguments. For arguments (1, sNaN) and (sNaN, 0), TS 18661-1
semantics are also that the result should be qNaN, whereas with a qNaN
argument there the result should be 1, but for the dbl-64
implementation of pow there are issues with sNaN arguments beyond not
implementing the TS 18661-1 semantics in those special cases.
This patch makes the implementations in sysdeps/ieee754 follow the TS
18661-1 semantics consistently. Because x86 / x86_64 implementations
still need fixing, testcases are not included with this patch; they
will be included with the fix for the x86 / x86_64 versions.
Tested for x86_64, x86, mips64 and powerpc (with such testcases, which
pass in the mips64 and powerpc cases).
[BZ #20916]
* sysdeps/ieee754/dbl-64/e_pow.c (__ieee754_pow): Do not return 1
for arguments (sNaN, 0) or (1, sNaN). Do arithmetic on NaN
arguments to compute result.
* sysdeps/ieee754/flt-32/e_powf.c (__ieee754_powf): Do not return
1 for arguments (sNaN, 0) or (1, sNaN).
* sysdeps/ieee754/ldbl-128/e_powl.c (__ieee754_powl): Likewise.
* sysdeps/ieee754/ldbl-128ibm/e_powl.c (__ieee754_powl): Likewise.
The dbl-64 implementation of __ieee754_pow returns a NaN for pow
(qNaN, 0) when it should return 1. Normally this is covered up by the
wrappers ending up calling __kernel_standard which fixes up the result
for this case, but for -lieee the wrappers are bypassed and the bad
result gets through as a return value.
Now, the wrappers fixing this are dealing with variant error handling
that wants a result of NaN for pow (qNaN, 0), and only ever call
__kernel_standard for this case if NaN resulted from __ieee754_pow.
This leads to a question of whether the dbl-64 code might be
deliberately returning NaN in order to use those code paths. However,
I can find no sign that this is deliberate. If it were deliberate one
would expect other implementations to do the same, and would expect
the return of NaN to be very old, but it appears it came in by
accident when the present e_pow.c implementation replaced an fdlibm
implementation in 2001. So it appears to be unintended that this path
through the pow wrapper could be used at all.
So this patch fixes the implementation to return 1 in this case as
expected. This is consistent with all the other implementations. The
relevant path through the wrappers is now unreachable, so is removed
(which is the main motivation of this patch: to avoid that path
becoming accidentally reachable when implementing TS 18661-1 semantics
that pow (sNaN, 0) should return qNaN with "invalid" raised). Another
path that would require __ieee754_pow (0, 0) to return 0 is also
unreachable (as all implementations return 1, in accordance with C99
semantics), so is removed as well.
Note: we don't have anything set up to test -lieee, which in any case
is obsolescent (at some point we should remove the ability for new
programs to access _LIB_VERSION or define matherr and have it called
by glibc). So testing will be implicit through sNaN tests added when
making sNaN inputs work correctly for pow functions.
Tested for x86_64 and x86.
[BZ #20919]
* sysdeps/ieee754/dbl-64/e_pow.c (__ieee754_pow): Do not return
NaN first argument when raised to power 0.
* math/w_pow.c (__pow): Do not check for NaN or zero results from
raising to power zero.
* math/w_powf.c (__powf): Likewise.
* math/w_powl.c (__powl): Likewise.
* sysdeps/ieee754/k_standard.c (__kernel_standard): Do not handle
pow (0, 0) or pow (NaN, 0).
TS 18661-1 defines llogb functions that are like ilogb except that
they return long int instead of int. Corresponding FP_LLOGB* macros
are defined, whose values are required to have the obvious
correspondence to those of the FP_ILOGB* macros.
This patch implements these functions and macros for glibc. llogb
uses the type-generic infrastructure, with an implementation similar
to the wrapper for ilogb but with additional conversion from FP_ILOGB*
to FP_LLOGB*; this approach avoids needing to modify or duplicate any
of the architecture-specific ilogb implementations. Tests are also
based on those for ilogb.
Ideally the llogb functions would alias the ilogb ones when long is
32-bit, but such aliasing requires the associated header declarations
of the different-type alias to be hidden, typically by defining macros
before including the header (see e.g. how
sysdeps/ieee754/dbl-64/wordsize-64/s_llround.c defines lround to
__hidden_lround before including <math.h>). The infrastructure for
type-generic function implementations does not support defining such
macros at present (since C code can't define a macro whose name is
determined by other macros). So this patch leaves them as separate
functions (similar to e.g. scalbln and scalbn being separate in such a
case as well), but with the remapping of FP_ILOGB* to FP_LLOGB*
conditioned out in the case where it would be the identity map.
Tested for x86_64, x86, mips64 and powerpc.
* math/bits/mathcalls.h [__GLIBC_USE (IEC_60559_BFP_EXT)] (llogb):
New declaration.
* math/tgmath.h [__GLIBC_USE (IEC_60559_BFP_EXT)] (llogb): New
macro.
* math/math.h [__GLIBC_USE (IEC_60559_BFP_EXT)] (__FP_LONG_MAX):
New macro.
[__GLIBC_USE (IEC_60559_BFP_EXT)] (FP_LLOGB0): Likewise.
[__GLIBC_USE (IEC_60559_BFP_EXT)] (FP_LLOGBNAN): Likewise.
* math/Versions (llogb): New libm symbol at version GLIBC_2.25.
(llogbf): Likewise.
(llogbl): Likewise.
* math/Makefile (gen-libm-calls): Add w_llogbF.
(tests): Add test-fp-llogb-constants.
* math/w_llogb_template.c: New file. Based on
math/w_ilogb_template.c.
* math/libm-test.inc (llogb_test_data): New array.
(llogb_test): New function.
(main): Call llogb_test.
* math/test-fp-llogb-constants.c: New file. Based on
math/test-fp-ilogb-constants.c.
* math/test-tgmath-ret.c (llogb): New CHECK_RET_CONST call.
(do_test): Call check_return_llogb.
* math/test-tgmath.c (NCALLS): Increase to 126.
(F(compile_test)): Call llogb.
(F(llogb)): New function.
* manual/math.texi (Exponents and Logarithms): Document llogb,
llogbf, llogbl, FP_LLOGB0 and FP_LLOGBNAN.
* manual/libm-err-tab.pl (@all_functions): Add llogb.
* sysdeps/ieee754/ldbl-opt/nldbl-llogb.c: New file.
* sysdeps/ieee754/ldbl-opt/w_llogbl.c: Likewise.
* sysdeps/ieee754/ldbl-opt/Makefile (libnldbl-calls): Add llogb.
(CFLAGS-nldbl-llogb.c): New variable.
* 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.
When I added the getpayload and setpayload functions I failed to make
the ldbl-128 functions use the _Float128 type name like most other
ldbl-128 functions do in preparation for being used to implement *f128
functions. This patch fixes them to use that name.
Tested for mips64.
* sysdeps/ieee754/ldbl-128/s_getpayloadl.c (getpayloadl): Use
_Float128 instead of long double.
* sysdeps/ieee754/ldbl-128/s_setpayloadl_main.c (FUNC): Likewise.
Commit c7debbdfac redirected the internal strrch to default powerpc64
implementation by redefining the weak_alias at
sysdeps/powerpc/powerpc64/multiarch/strchr-ppc64.c:
#undef weak_alias
#define weak_alias(name, aliasname) \
extern __typeof (__strrchr_ppc) aliasname \
__attribute__ ((weak, alias ("__strrchr_ppc")));
This creates a __GI_strchr alias that clashes with the IFUNC symbol in
stprchr.os. There is not need to define the default version for internal
version, since ifunc should work internally for powerpc64. This patch
removes the weak_alias indirection.
Checked on powerpc64le.
* sysdeps/powerpc/powerpc64/multiarch/strrchr-ppc64.c (weak_alias):
Remove redirection to __strrchr_ppc.
Continuing the refactoring of bits/mathdef.h, this patch stops it
defining FP_ILOGB0 and FP_ILOGBNAN, moving the required information to
a new header bits/fp-logb.h.
There are only two possible values of each of those macros permitted
by ISO C. TS 18661-1 adds corresponding macros for llogb, and their
values are required to correspond to those of the ilogb macros in the
obvious way. Thus two boolean values - for which the same choices are
correct for most architectures - suffice to determine the value of all
these macros, and by defining macros for those boolean values in
bits/fp-logb.h we can then define the public FP_* macros in math.h and
avoid the present duplication of the associated feature test macro
logic.
This patch duly moves to bits/fp-logb.h defining __FP_LOGB0_IS_MIN and
__FP_LOGBNAN_IS_MIN. Default definitions of those to 0 are correct
for both architectures, while ia64, m68k and x86 get their own
versions of bits/fp-logb.h to reflect their use of values different
from the defaults.
The patch renders many copies of bits/mathdef.h trivial (needed only
to avoid the default __NO_LONG_DOUBLE_MATH). I'll revise
<https://sourceware.org/ml/libc-alpha/2016-11/msg00865.html>
accordingly so that it removes all bits/mathdef.h headers except the
default one and the alpha one, and arranges for the header to be
included only by complex.h as the only remaining use at that point
will be for the alpha ABI issues there.
Tested for x86_64 and x86. Also did compile-only testing with
build-many-glibcs.py (using glibc sources from before the commit that
introduced many build failures with undefined __GI___sigsetjmp).
* bits/fp-logb.h: New file.
* sysdeps/ia64/bits/fp-logb.h: Likewise.
* sysdeps/m68k/m680x0/bits/fp-logb.h: Likewise.
* sysdeps/x86/bits/fp-logb.h: Likewise.
* math/Makefile (headers): Add bits/fp-logb.h.
* math/math.h: Include <bits/fp-logb.h>.
[__USE_ISOC99] (FP_ILOGB0): Define based on __FP_LOGB0_IS_MIN.
[__USE_ISOC99] (FP_ILOGBNAN): Define based on __FP_LOGBNAN_IS_MIN.
* bits/mathdef.h (FP_ILOGB0): Remove.
(FP_ILOGBNAN): Likewise.
* sysdeps/aarch64/bits/mathdef.h (FP_ILOGB0): Likewise.
(FP_ILOGBNAN): Likewise.
* sysdeps/alpha/bits/mathdef.h (FP_ILOGB0): Likewise.
(FP_ILOGBNAN): Likewise.
* sysdeps/ia64/bits/mathdef.h (FP_ILOGB0): Likewise.
(FP_ILOGBNAN): Likewise.
* sysdeps/m68k/m680x0/bits/mathdef.h (FP_ILOGB0): Likewise.
(FP_ILOGBNAN): Likewise.
* sysdeps/mips/bits/mathdef.h (FP_ILOGB0): Likewise.
(FP_ILOGBNAN): Likewise.
* sysdeps/powerpc/bits/mathdef.h (FP_ILOGB0): Likewise.
(FP_ILOGBNAN): Likewise.
* sysdeps/s390/bits/mathdef.h (FP_ILOGB0): Likewise.
(FP_ILOGBNAN): Likewise.
* sysdeps/sparc/bits/mathdef.h (FP_ILOGB0): Likewise.
(FP_ILOGBNAN): Likewise.
* sysdeps/x86/bits/mathdef.h (FP_ILOGB0): Likewise.
(FP_ILOGBNAN): Likewise.
Commit 142e0a9953 redirected the internal stpcpy to default powerpc64
implementation by redefining the weak_alias at
sysdeps/powerpc/powerpc64/multiarch/stpcpy-ppc64.c:
#undef weak_alias
#define weak_alias(name, aliasname) \
extern __typeof (__stpcpy_ppc) aliasname \
__attribute__ ((weak, alias ("__stpcpy_ppc")));
This creates a __GI_stpcpy alias that clashes with the IFUNC symbol in
stpcpy.os. There is not need to define the default version for internal
version, since ifunc should work internally for powerpc64. This patch
removes the weak_alias indirection.
Checked on powerpc64le.
* sysdeps/powerpc/powerpc64/multiarch/stpcpy-ppc64.c (weak_alias):
Remove redirection to __stpcpy_ppc.
It is no longer needed since commit 6c444ad6e9
(elf: Do not use memalign for TCB/TLS blocks allocation [BZ #17730]).
Applications do not link against ld.so and will use the definition in
libc.so, so there is no ABI impact.
This change moves the main implementation of _dl_catch_error,
_dl_signal_error to libc.so, where TLS variables can be used
directly. This removes a writable function pointer from the
rtld_global variable.
For use during initial relocation, minimal implementations of these
functions are provided in ld.so. These are eventually interposed
by the libc.so implementations. This is implemented by compiling
elf/dl-error-skeleton.c twice, via elf/dl-error.c and
elf/dl-error-minimal.c.
As a side effect of this change, the static version of dl-error.c
no longer includes support for the
_dl_signal_cerror/_dl_receive_error mechanism because it is only
used in ld.so.
* sysdeps/unix/sysv/linux/generic/wordsize-32/fxstat.c: Do not define
fxstat if XSTAT_IS_XSTAT64 is set to non-zero.
* sysdeps/unix/sysv/linux/generic/wordsize-32/fxstatat.c: Ditto for
fxstatat.
* sysdeps/unix/sysv/linux/generic/wordsize-32/lxstat.c: Ditto for
lxstat.
* sysdeps/unix/sysv/linux/generic/wordsize-32/xstat.c: Ditto for xstat.
* sysdeps/unix/sysv/linux/generic/wordsize-32/fxstat64.c: New file.
* sysdeps/unix/sysv/linux/generic/wordsize-32/fxstatat64.c: New file.
* sysdeps/unix/sysv/linux/generic/wordsize-32/lxstat64.c: Make __lxstat
an alias of __lxstat64 if XSTAT_IS_XSTAT64 is set to non-zero.
* sysdeps/unix/sysv/linux/generic/wordsize-32/xstat64.c: Ditto for
__xstat.
The __longjmp symbol was left in accidentally. It is not exported
through a Versions file, but through a .symver assembler directive.
The corresponding exported symbol was removed from the non-fpu
powerpc64 targets in commit 9b9ef82358.
Continuing the refactoring of bits/mathdef.h, this patch moves the
FP_FAST_* definitions into a new bits/fp-fast.h header. Currently
this is only for FP_FAST_FMA*, but in future it would be the
appropriate place for the FP_FAST_* macros from TS 18661-1 as well.
The generic bits/mathdef.h header defines these macros based on
whether the compiler defines __FP_FAST_*. Most architecture-specific
headers, however, fail to do so, meaning that if the architecture (or
some particular processors) does in fact have fused operations, and
GCC knows to use them inline, the FP_FAST_* macros will still not be
defined.
By refactoring, this patch causes the generic version (based on
__FP_FAST_*) to be used in more cases, and so the macro definitions to
be more accurate. Architectures that already defined some or all of
these macros other than based on the predefines have their own
versions of fp-fast.h, which are arranged so they define FP_FAST_* if
either the architecture-specific conditions are true or __FP_FAST_*
are defined.
After this refactoring, various bits/mathdef.h headers for
architectures with long double = double are semantically identical to
the generic version. The patch removes those headers that are
redundant. (In fact two of the four removed were already redundant
before this patch because they did use __FP_FAST_*.)
Tested for x86_64 and x86, and compilation-only with
build-many-glibcs.py.
* bits/fp-fast.h: New file.
* sysdeps/aarch64/bits/fp-fast.h: Likewise.
* sysdeps/powerpc/bits/fp-fast.h: Likewise.
* math/Makefile (headers): Add bits/fp-fast.h.
* math/math.h: Include <bits/fp-fast.h>.
* bits/mathdef.h (FP_FAST_FMA): Remove.
(FP_FAST_FMAF): Likewise.
(FP_FAST_FMAL): Likewise.
* sysdeps/aarch64/bits/mathdef.h (FP_FAST_FMA): Likewise.
(FP_FAST_FMAF): Likewise.
* sysdeps/powerpc/bits/mathdef.h (FP_FAST_FMA): Likewise.
(FP_FAST_FMAF): Likewise.
* sysdeps/x86/bits/mathdef.h (FP_FAST_FMA): Likewise.
(FP_FAST_FMAF): Likewise.
(FP_FAST_FMAL): Likewise.
* sysdeps/arm/bits/mathdef.h: Remove file.
* sysdeps/hppa/fpu/bits/mathdef.h: Likewise.
* sysdeps/sh/sh4/bits/mathdef.h: Likewise.
* sysdeps/tile/bits/mathdef.h: Likewise.
This patch converts the ilogb wrappers (which set errno directly
rather than doing anything with __kernel_standard) to use the
type-generic template machinery. This is intended as preparation for
adding llogb.
Tested for x86_64 and x86, and tested compile for other architectures
with build-many-glibcs.py.
* math/w_ilogb_template.c: New file. Based on math/w_ilogb.c.
* math/w_ilogb.c: Remove.
* math/w_ilogbf.c: Likewise.
* math/w_ilogbl.c: Likewise.
* sysdeps/ieee754/ldbl-opt/w_ilogb.c: Likewise.
* sysdeps/ieee754/ldbl-opt/w_ilogbl.c: Likewise.
* math/Makefile (gen-libm-calls): Add w_ilogbF.
(libm-calls): Remove w_ilogbF.
* sysdeps/ieee754/ldbl-opt/math-type-macros-double.h
(LDOUBLE_ilogbl_libm_version): New macro.
Building tests for IA64 runs into a build failure compiling
stdlib/tst-setcontext2.c:
tst-setcontext2.c: In function 'do_test':
tst-setcontext2.c:210:20: error: passing argument 1 of 'sigismember' from incompatible pointer type [-Werror=incompatible-pointer-types]
if (sigismember (&oldctx.uc_sigmask, SIGUSR2) != 1)
^
Indeed, the IA64 uc_sigmask as unsigned long rather than the larger
userspace sigset_t. Fixing this might be hard; this patch works
around the build failure by making IA64 wrap the test with a version
that #defines sigismember to add a cast (I'd welcome a better approach
for fixing this).
Tested (compilation only) for ia64.
* sysdeps/unix/sysv/linux/ia64/tst-setcontext2.c: New file.
IA64 builds in math/ use "-include libm-symbols.h". This breaks the
signgam tests, which rely on undefining _LIBC and feature test macros
and defining _ISOMAC before including system headers to get them to
provide only ISO C declarations (libm-symbols.h ending up indirectly
including headers which result in this breaking); similarly, it breaks
C++ tests as some headers included from libm-symbols.h are not ready
for inclusion in C++ code. This patch disables the contents of
libm-symbols.h if __STRICT_ANSI__ or __cplusplus are defined to avoid
this problem (this header can only test symbols defined before the
source file is processed, so can't test _ISOMAC because that's defined
within the source file, after this header is included).
Tested (compilation only) for ia64.
* sysdeps/ia64/fpu/libm-symbols.h: Make contents conditional on
[!__STRICT_ANSI__ && !__cplusplus].
There is no need to use PLT nor GOT in static archives to branch to a
function, regardless whether static archives is compiled with PIC or
not. When static archives are used to create dynamic executable,
PLT/GOT may be used. The resulting executable still works correctly.
[BZ #20750]
* sysdeps/x86_64/sysdep.h (JUMPTARGET): Check SHARED instead
of PIC.
* sysdeps/unix/sysv/linux/fstatfs64.c: Reorder include files,
only alias fstatfs and __fstatfs if STATFS_IS_STATFS64 is non-zero.
* sysdeps/unix/sysv/linux/statfs64.c: Ditto for statfs and __statfs.
The nios2 sys/cachectl.h includes a kernel header asm/cachectl.h,
which does not exist, so causing the check-installed-headers tests to
fail. This patch removes the include of a nonexistent header.
Tested (compilation only) for nios2.
* sysdeps/unix/sysv/linux/nios2/sys/cachectl.h: Do not include
<asm/cachectl.h>.
TS 18661-1 defines functions for manipulating the payloads of NaNs.
This patch implements the setpayloadsig functions for glibc; these are
like the setpayload functions, but produce a signaling NaN instead of
a quiet NaN.
The substance of the implementation was included with the setpayload
implementation, so the new files here just need to wrap the main files
with different defines to build the new functions.
Because the functions store a signaling NaN via a pointer and the
libm-test macros choose a suitable initial value for the variable in
such a case by comparing with the expected value, the relevant macro
needs to clear exceptions after FE_INVALID may have been raised by
that comparison.
Tested for x86_64, x86, mips64 and powerpc.
* math/bits/mathcalls.h [__GLIBC_USE (IEC_60559_BFP_EXT)]
(setpayloadsig): New declaration.
* math/Versions (setpayloadsig): New libm symbol at version
GLIBC_2.25.
(setpayloadsigf): Likewise.
(setpayloadsigl): Likewise.
* math/Makefile (libm-calls): Add s_setpayloadsigF.
* math/libm-test.inc (RUN_TEST_Ff_b1): Call feclearexcept
(FE_ALL_EXCEPT) after initializing EXTRA_VAR.
(setpayloadsig_test_data): New array.
(setpayloadsig_test): New function.
(main): Call setpayloadsig_test.
* manual/arith.texi (FP Bit Twiddling): Document setpayloadsig,
setpayloadsigf and setpayloadsigl.
* manual/libm-err-tab.pl: Update comment on interfaces without
ulps tabulated.
* sysdeps/ieee754/dbl-64/s_setpayloadsig.c: New file.
* sysdeps/ieee754/flt-32/s_setpayloadsigf.c: Likewise.
* sysdeps/ieee754/ldbl-128/s_setpayloadsigl.c: Likewise.
* sysdeps/ieee754/ldbl-128ibm/s_setpayloadsigl.c: Likewise.
* sysdeps/ieee754/ldbl-96/s_setpayloadsigl.c: Likewise.
* sysdeps/ieee754/ldbl-opt/nldbl-setpayloadsig.c: Likewise.
* sysdeps/ieee754/ldbl-opt/Makefile (libnldbl-calls): Add
setpayloadsig.
(CFLAGS-nldbl-setpayloadsig.c): New variable.
* 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.
This patch remove the PID cache and usage in current GLIBC code. Current
usage is mainly used a performance optimization to avoid the syscall,
however it adds some issues:
- The exposed clone syscall will try to set pid/tid to make the new
thread somewhat compatible with current GLIBC assumptions. This cause
a set of issue with new workloads and usecases (such as BZ#17214 and
[1]) as well for new internal usage of clone to optimize other algorithms
(such as clone plus CLONE_VM for posix_spawn, BZ#19957).
- The caching complexity also added some bugs in the past [2] [3] and
requires more effort of each port to handle such requirements (for
both clone and vfork implementation).
- Caching performance gain in mainly on getpid and some specific
code paths. The getpid performance leverage is questionable [4],
either by the idea of getpid being a hotspot as for the getpid
implementation itself (if it is indeed a justifiable hotspot a
vDSO symbol could let to a much more simpler solution).
Other usage is mainly for non usual code paths, such as pthread
cancellation signal and handling.
For thread creation (on stack allocation) the code simplification in fact
adds some performance gain due the no need of transverse the stack cache
and invalidate each element pid.
Other thread usages will require a direct getpid syscall, such as
cancellation/setxid signal, thread cancellation, thread fail path (at
create_thread), and thread signal (pthread_kill and pthread_sigqueue).
However these are hardly usual hotspots and I think adding a syscall is
justifiable.
It also simplifies both the clone and vfork arch-specific implementation.
And by review each fork implementation there are some discrepancies that
this patch also solves:
- microblaze clone/vfork does not set/reset the pid/tid field
- hppa uses the default vfork implementation that fallback to fork.
Since vfork is deprecated I do not think we should bother with it.
The patch also removes the TID caching in clone. My understanding for
such semantic is try provide some pthread usage after a user program
issue clone directly (as done by thread creation with CLONE_PARENT_SETTID
and pthread tid member). However, as stated before in multiple discussions
threads, GLIBC provides clone syscalls without further supporting all this
semantics.
I ran a full make check on x86_64, x32, i686, armhf, aarch64, and powerpc64le.
For sparc32, sparc64, and mips I ran the basic fork and vfork tests from
posix/ folder (on a qemu system). So it would require further testing
on alpha, hppa, ia64, m68k, nios2, s390, sh, and tile (I excluded microblaze
because it is already implementing the patch semantic regarding clone/vfork).
[1] https://codereview.chromium.org/800183004/
[2] https://sourceware.org/ml/libc-alpha/2006-07/msg00123.html
[3] https://sourceware.org/bugzilla/show_bug.cgi?id=15368
[4] http://yarchive.net/comp/linux/getpid_caching.html
* sysdeps/nptl/fork.c (__libc_fork): Remove pid cache setting.
* nptl/allocatestack.c (allocate_stack): Likewise.
(__reclaim_stacks): Likewise.
(setxid_signal_thread): Obtain pid through syscall.
* nptl/nptl-init.c (sigcancel_handler): Likewise.
(sighandle_setxid): Likewise.
* nptl/pthread_cancel.c (pthread_cancel): Likewise.
* sysdeps/unix/sysv/linux/pthread_kill.c (__pthread_kill): Likewise.
* sysdeps/unix/sysv/linux/pthread_sigqueue.c (pthread_sigqueue):
Likewise.
* sysdeps/unix/sysv/linux/createthread.c (create_thread): Likewise.
* sysdeps/unix/sysv/linux/getpid.c: Remove file.
* nptl/descr.h (struct pthread): Change comment about pid value.
* nptl/pthread_getattr_np.c (pthread_getattr_np): Remove thread
pid assert.
* sysdeps/unix/sysv/linux/pthread-pids.h (__pthread_initialize_pids):
Do not set pid value.
* nptl_db/td_ta_thr_iter.c (iterate_thread_list): Remove thread
pid cache check.
* nptl_db/td_thr_validate.c (td_thr_validate): Likewise.
* sysdeps/aarch64/nptl/tcb-offsets.sym: Remove pid offset.
* sysdeps/alpha/nptl/tcb-offsets.sym: Likewise.
* sysdeps/arm/nptl/tcb-offsets.sym: Likewise.
* sysdeps/hppa/nptl/tcb-offsets.sym: Likewise.
* sysdeps/i386/nptl/tcb-offsets.sym: Likewise.
* sysdeps/ia64/nptl/tcb-offsets.sym: Likewise.
* sysdeps/m68k/nptl/tcb-offsets.sym: Likewise.
* sysdeps/microblaze/nptl/tcb-offsets.sym: Likewise.
* sysdeps/mips/nptl/tcb-offsets.sym: Likewise.
* sysdeps/nios2/nptl/tcb-offsets.sym: Likewise.
* sysdeps/powerpc/nptl/tcb-offsets.sym: Likewise.
* sysdeps/s390/nptl/tcb-offsets.sym: Likewise.
* sysdeps/sh/nptl/tcb-offsets.sym: Likewise.
* sysdeps/sparc/nptl/tcb-offsets.sym: Likewise.
* sysdeps/tile/nptl/tcb-offsets.sym: Likewise.
* sysdeps/x86_64/nptl/tcb-offsets.sym: Likewise.
* sysdeps/unix/sysv/linux/aarch64/clone.S: Remove pid and tid caching.
* sysdeps/unix/sysv/linux/alpha/clone.S: Likewise.
* sysdeps/unix/sysv/linux/arm/clone.S: Likewise.
* sysdeps/unix/sysv/linux/hppa/clone.S: Likewise.
* sysdeps/unix/sysv/linux/i386/clone.S: Likewise.
* sysdeps/unix/sysv/linux/ia64/clone2.S: Likewise.
* sysdeps/unix/sysv/linux/mips/clone.S: Likewise.
* sysdeps/unix/sysv/linux/nios2/clone.S: Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc32/clone.S: Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc64/clone.S: Likewise.
* sysdeps/unix/sysv/linux/s390/s390-32/clone.S: Likewise.
* sysdeps/unix/sysv/linux/s390/s390-64/clone.S: Likewise.
* sysdeps/unix/sysv/linux/sh/clone.S: Likewise.
* sysdeps/unix/sysv/linux/sparc/sparc32/clone.S: Likewise.
* sysdeps/unix/sysv/linux/sparc/sparc64/clone.S: Likewise.
* sysdeps/unix/sysv/linux/tile/clone.S: Likewise.
* sysdeps/unix/sysv/linux/x86_64/clone.S: Likewise.
* sysdeps/unix/sysv/linux/aarch64/vfork.S: Remove pid set and reset.
* sysdeps/unix/sysv/linux/alpha/vfork.S: Likewise.
* sysdeps/unix/sysv/linux/arm/vfork.S: Likewise.
* sysdeps/unix/sysv/linux/i386/vfork.S: Likewise.
* sysdeps/unix/sysv/linux/ia64/vfork.S: Likewise.
* sysdeps/unix/sysv/linux/m68k/clone.S: Likewise.
* sysdeps/unix/sysv/linux/m68k/vfork.S: Likewise.
* sysdeps/unix/sysv/linux/mips/vfork.S: Likewise.
* sysdeps/unix/sysv/linux/nios2/vfork.S: Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc32/vfork.S: Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc64/vfork.S: Likewise.
* sysdeps/unix/sysv/linux/s390/s390-32/vfork.S: Likewise.
* sysdeps/unix/sysv/linux/s390/s390-64/vfork.S: Likewise.
* sysdeps/unix/sysv/linux/sh/vfork.S: Likewise.
* sysdeps/unix/sysv/linux/sparc/sparc32/vfork.S: Likewise.
* sysdeps/unix/sysv/linux/sparc/sparc64/vfork.S: Likewise.
* sysdeps/unix/sysv/linux/tile/vfork.S: Likewise.
* sysdeps/unix/sysv/linux/x86_64/vfork.S: Likewise.
* sysdeps/unix/sysv/linux/tst-clone2.c (f): Remove direct pthread
struct access.
(clone_test): Remove function.
(do_test): Rewrite to take in consideration pid is not cached anymore.
At present, definitions of float_t and double_t are split among many
bits/mathdef.h headers.
For all but three architectures, these types are float and double.
Furthermore, if you assume __FLT_EVAL_METHOD__ to be defined, that
provides a more generic way of determining the correct values of these
typedefs. Defining these typedefs more generally based on
__FLT_EVAL_METHOD__ was previously proposed by Paul Eggert in
<https://sourceware.org/ml/libc-alpha/2012-02/msg00002.html>.
This patch refactors things in the way I proposed in
<https://sourceware.org/ml/libc-alpha/2016-11/msg00745.html>. A new
header bits/flt-eval-method.h defines a single macro,
__GLIBC_FLT_EVAL_METHOD, which is then used by math.h to define
float_t and double_t. The default is based on __FLT_EVAL_METHOD__
(although actually a default to 0 would have the same effect for
current ports, because ports where values other than 0 or 16 are
possible all have their own headers).
To avoid changing the existing semantics in any case, including for
compilers not defining __FLT_EVAL_METHOD__, architecture-specific
files are then added for m68k, s390, x86 which replicate the existing
semantics. At least with __FLT_EVAL_METHOD__ values possible with
GCC, there should be no change to the choices of float_t and double_t
for any supported configuration.
Architecture maintainer notes:
* m68k: sysdeps/m68k/m680x0/bits/flt-eval-method.h always defines
__GLIBC_FLT_EVAL_METHOD to 2 to replicate the existing logic. But
actually GCC defines __FLT_EVAL_METHOD__ to 0 if TARGET_68040. It
might make sense to make the header prefer to base things on
__FLT_EVAL_METHOD__ if defined, like the x86 version, and so make
the choices of these types more accurate (with a NEWS entry as for
the other changes to these types on particular architectures).
* s390: sysdeps/s390/bits/flt-eval-method.h always defines
__GLIBC_FLT_EVAL_METHOD to 1 to replicate the existing logic. As
previously discussed, it might make sense in coordination with GCC
to eliminate the historic mistake, avoid excess precision in the
-fexcess-precision=standard case and make the typedefs match (with a
NEWS entry, again).
Tested for x86-64 and x86. Also did compilation-only testing with
build-many-glibcs.py.
* bits/flt-eval-method.h: New file.
* sysdeps/m68k/m680x0/bits/flt-eval-method.h: Likewise.
* sysdeps/s390/bits/flt-eval-method.h: Likewise.
* sysdeps/x86/bits/flt-eval-method.h: Likewise.
* math/Makefile (headers): Add bits/flt-eval-method.h.
* math/math.h: Include <bits/flt-eval-method.h>.
[__USE_ISOC99] (float_t): Define based on __GLIBC_FLT_EVAL_METHOD.
[__USE_ISOC99] (double_t): Likewise.
* bits/mathdef.h (float_t): Remove.
(double_t): Likewise.
* sysdeps/aarch64/bits/mathdef.h (float_t): Likewise.
(double_t): Likewise.
* sysdeps/alpha/bits/mathdef.h (float_t): Likewise.
(double_t): Likewise.
* sysdeps/arm/bits/mathdef.h (float_t): Likewise.
(double_t): Likewise.
* sysdeps/hppa/fpu/bits/mathdef.h (float_t): Likewise.
(double_t): Likewise.
* sysdeps/ia64/bits/mathdef.h (float_t): Likewise.
(double_t): Likewise.
* sysdeps/m68k/m680x0/bits/mathdef.h (float_t): Likewise.
(double_t): Likewise.
* sysdeps/mips/bits/mathdef.h (float_t): Likewise.
(double_t): Likewise.
* sysdeps/powerpc/bits/mathdef.h (float_t): Likewise.
(double_t): Likewise.
* sysdeps/s390/bits/mathdef.h (float_t): Likewise.
(double_t): Likewise.
* sysdeps/sh/sh4/bits/mathdef.h (float_t): Likewise.
(double_t): Likewise.
* sysdeps/sparc/bits/mathdef.h (float_t): Likewise.
(double_t): Likewise.
* sysdeps/tile/bits/mathdef.h (float_t): Likewise.
(double_t): Likewise.
* sysdeps/x86/bits/mathdef.h (float_t): Likewise.
(double_t): Likewise.
When glibc is compiled with gcc 6.2 that has been configured with
to default to PIC/PIE, the static version of __memcpy_chk is not built,
as the test is done on PIC instead of SHARED. Fix the test to check for
SHARED, like it is done for similar functions like memmove_chk.
Changelog:
* sysdeps/x86_64/memcpy_chk.S (__memcpy_chk): Check for SHARED
instead of PIC.
