Commit Graph

36616 Commits

Author SHA1 Message Date
Zong Li
15b38ffc10 riscv: Get cache information through sysconf
Add support to query cache information on RISC-V through sysconf()
function. The cache information had been added in AUX vector of RISC-V
architecture in Linux kernel v.5.10-rc1.
Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com>
Acked-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-11-10 14:43:49 -05:00
Jim Wilson
1f67f23fdf RISC-V: Add _dl_start_user.
This is required for the debugglibc.sh script to work.  Tested by
successfully using this patched script, and a riscv64-linux testsuite
run.

We could perhaps call RTLD_EPILOGUE for ENTRY_POINT before calling
RTLD_PROLOGUE for _dl_start_user, but I don't think it matters.

OK?

Jim
2020-11-10 14:02:46 -05:00
Adhemerval Zanella
75a193b761 linux: Allow adjtime with NULL argument [BZ #26833]
The adjtime interface allows return the amount of time remaining
from any previous adjustment that has not yet been completed by
passing a NULL as first argument.  This was introduced with y2038
support 0308077e3a.

Checked on i686-linux-gnu.

Reviewed-by: Lukasz Majewski <lukma@denx.de>
2020-11-09 11:19:35 -03:00
Florian Weimer
5edf3d9fd6 aarch64: Add unwind information to _start (bug 26853)
This adds CFI directives which communicate that the stack ends
with this function.

Fixes bug 26853.
2020-11-09 11:31:04 +01:00
Samuel Thibault
dfe2e7a562 bsd unlockpt: unlockpt needs to fail with EINVAL, not ENOTTY
The EINVAL error code is mandated by POSIX, while ptsname_r returns
ENOTTY, so we need to translate.
2020-11-08 14:06:56 +00:00
Samuel Thibault
aa11ab9953 Rearrange bsd_getpt vs bsd_openpt and implement posix_openpt on BSD
* sysdeps/unix/bsd/getpt.c (__getpt): Add oflag parameter, pass
it to the _open call and rename to...
(__bsd_openpt): ... new function.
(__getpt): Reimplement on top of __bsd_openpt.
(__posix_openpt): Replace stub with implementation on top of __bsd_openpt.
(posix_openpt): Remove stub warning.
2020-11-07 21:25:37 +01:00
Siddhesh Poyarekar
34aec973e1 Remove __warndecl
The macro is not used anymore, so remove it and warning-nop.c.

Reviewed-by: Florian Weimer <fweimer@redhat.com>
2020-11-05 15:11:42 +05:30
Siddhesh Poyarekar
dc274b1416 Remove __warn_memset_zero_len [BZ #25399]
Non-gcc compilers (clang and possibly other compilers that do not
masquerade as gcc 5.0 or later) are unable to use
__warn_memset_zero_len since the symbol is no longer available on
glibc built with gcc 5.0 or later.  While it was likely an oversight
that caused this omission, the fact that it wasn't noticed until
recently (when clang closed the gap on _FORTIFY_SUPPORT) that the
symbol was missing.

Given that both gcc and clang are capable of doing this check in the
compiler, drop all remaining signs of __warn_memset_zero_len from
glibc so that no more objects are built with this symbol in future.
2020-11-05 10:02:10 +05:30
Arjun Shankar
9a99c68214 iconv: Accept redundant shift sequences in IBM1364 [BZ #26224]
The IBM1364, IBM1371, IBM1388, IBM1390 and IBM1399 character sets
share converter logic (iconvdata/ibm1364.c) which would reject
redundant shift sequences when processing input in these character
sets.  This led to a hang in the iconv program (CVE-2020-27618).

This commit adjusts the converter to ignore redundant shift sequences
and adds test cases for iconv_prog hangs that would be triggered upon
their rejection.  This brings the implementation in line with other
converters that also ignore redundant shift sequences (e.g. IBM930
etc., fixed in commit 692de4b396).

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2020-11-04 12:19:38 +01:00
Lukasz Majewski
bb0719a80d msg: Remove redundant #include <sys/msg.h> header
The #include <sys/msg.h> is redundant as we do not use message specific
types for issuing syscalls to handle msg and shm. Only msgctl requires
this header.

Build tests:
./src/scripts/build-many-glibcs.py glibcs
2020-11-04 11:34:58 +01:00
H.J. Lu
fbb71eddb3 tst-setuid1-static-ENV: Add $(common-objpfx)nss [BZ #26820]
commit def674652e
Author: Florian Weimer <fweimer@redhat.com>
Date:   Mon Apr 27 15:00:14 2020 +0200

    nptl/tst-setuid1-static: Improve isolation from system objects

    Static dlopen needs an LD_LIBRARY_PATH setting to avoid loading system
    libraries.

missed $(common-objpfx)nss.  Add $(common-objpfx)nss to LD_LIBRARY_PATH
for tst-setuid1-static to support

  struct passwd *pwd = getpwnam ("nobody");

in nptl/tst-setuid1.c.
2020-11-03 12:04:42 -08:00
Szabolcs Nagy
e156dabc76 aarch64: Add variant PCS lazy binding test [BZ #26798]
This test fails without bug 26798 fixed because some integer registers
likely get clobbered by lazy binding and variant PCS only allows x16
and x17 to be clobbered at call time.

The test requires binutils 2.32.1 or newer for handling variant PCS
symbols. SVE registers are not covered by this test, to avoid the
complexity of handling multiple compile- and runtime feature support
cases.
2020-11-02 09:39:24 +00:00
Szabolcs Nagy
558251bd87 aarch64: Fix DT_AARCH64_VARIANT_PCS handling [BZ #26798]
The variant PCS support was ineffective because in the common case
linkmap->l_mach.plt == 0 but then the symbol table flags were ignored
and normal lazy binding was used instead of resolving the relocs early.
(This was a misunderstanding about how GOT[1] is setup by the linker.)

In practice this mainly affects SVE calls when the vector length is
more than 128 bits, then the top bits of the argument registers get
clobbered during lazy binding.

Fixes bug 26798.
2020-11-02 09:39:24 +00:00
Jonny Grant
fd0981e402 hurd: Correct 'ethenet' spelling
Signed-off-by: Jonny Grant <jg@jguk.org>
2020-10-31 02:04:22 +01:00
Joseph Myers
548f467fa1 Avoid -Wstringop-overflow warning in pthread_cleanup_push macros
GCC 11 introduces a -Wstringop-overflow warning for calls to functions
with an array argument passed as a pointer to memory not large enough
for that array.  This includes the __sigsetjmp calls from
pthread_cleanup_push macros, because those use a structure in
__pthread_unwind_buf_t, which has a common initial subsequence with
jmp_buf but does not include the saved signal mask; this is OK in this
case because the second argument to __sigsetjmp is 0 so the signal
mask is not accessed.

To avoid this warning, use a function alias __sigsetjmp_cancel with
first argument an array of exactly the type used in the calls to the
function, if using GCC 11 or later.  With older compilers, continue to
use __sigsetjmp with a cast, to avoid any issues with compilers
predating the returns_twice attribute not applying the same special
handling to __sigsetjmp_cancel as to __sigsetjmp.

Tested with build-many-glibcs.py for arm-linux-gnueabi that this fixes
the testsuite build failures.
2020-10-30 22:25:42 +00:00
Joseph Myers
882774658c Disable spurious -Warray-bounds for ypclnt.c (bug 26687)
Included among the GCC 11 warnings listed in bug 26687, but not fixed
when that bug was marked as FIXED, are -Warray-bounds warnings in
nis/ypclnt.c.  These are all for different calls to the same piece of
code, which already has a comment explaining that the element accessed
is in a common prefix of the various structures.  On the basis of that
comment, this patch treats the warning as a false positive and
disables it for that code.

Tested with build-many-glibcs.py for arm-linux-gnueabi, where,
together with my previous two patches, this allows the build of glibc
to complete with GCC 11 (further build failures appear in the
testsuite).

Reviewed-by: DJ Delorie <dj@redhat.com>
2020-10-30 21:40:25 +00:00
Joseph Myers
5c3b0374eb Do not use array parameter to new_composite_name (bug 26726)
Among the warnings causing a glibc build with GCC 11 to fail is one
for a call new_composite_name in setlocale.c.  The newnames argument
is declared as an array with __LC_LAST elements, but when the category
argument is not LC_ALL, it actually only has one element.  Since the
number of elements depends on the first argument to the function, it
seems clearer to declare the argument as a pointer.

Tested with build-many-glibcs.py for arm-linux-gnueabi, where this
allows the build to get further.

Reviewed-by: DJ Delorie <dj@redhat.com>
2020-10-30 21:39:12 +00:00
Joseph Myers
2098d4034d Disable spurious -Wstringop-overflow for setjmp/longjmp (bug 26647)
Building glibc with GCC 11 fails with (among other warnings) spurious
-Wstringop-overflow warnings from calls to setjmp and longjmp with a
pointer to a pthread_unwind_buf that is smaller than jmp_buf.  As
discussed in bug 26647, the warning in libc-start.c is a false
positive, because setjmp and longjmp do not access anything (the
signal mask) beyond the common prefix of the two structures, so this
patch disables the warning for that call to setjmp, as well as for two
calls in NPTL code that produce the same warning and look like false
positives for the same reason.

Tested with build-many-glibcs.py for arm-linux-gnueabi, where this
allows the build to get further.

Reviewed-by: DJ Delorie <dj@redhat.com>
2020-10-30 21:38:31 +00:00
liqingqing
961d12d947 malloc debug: fix compile error when enable macro MALLOC_DEBUG > 1
malloc debug: fix compile error when enable macro MALLOC_DEBUG > 1.

this is because commit e9c4fe93b3 has change the struct malloc_chunk's member "size" to "mchunk_size".

the reproduction is like that:
setp1: modify related Makefile.
vim ../glibc/malloc/Makefile
CPPFLAGS-malloc.o += -DMALLOC_DEBUG=2

step2: ../configure --prefix=/usr
       make -j32

this will cause the compile error:
/home/liqingqing/glibc_upstream/buildglibc/malloc/malloc.o
In file included from malloc.c:1899:0:
arena.c: In function 'dump_heap':
arena.c:422:58: error: 'struct malloc_chunk' has no member named 'size'
       fprintf (stderr, "chunk %p size %10lx", p, (long) p->size);
                                                          ^~
arena.c:428:17: error: 'struct malloc_chunk' has no member named 'size'
       else if (p->size == (0 | PREV_INUSE))

Reviewed-by: DJ Delorie <dj@redhat.com>
2020-10-30 14:49:08 -04:00
liqingqing
024f873209 tst-tcfree2: adjust coding style.
tst-tcfree2: adjust coding style.

Reviewed-by: DJ Delorie <dj@redhat.com>
2020-10-30 14:47:29 -04:00
Florian Weimer
5e598c2bbf elf: In ldconfig, extract the new_sub_entry function from search_dir
Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2020-10-30 18:40:28 +01:00
Joseph Myers
b853a4176c Use MPC 1.2.1 in build-many-glibcs.py.
This patch makes build-many-glibcs.py use the new MPC 1.2.1 release.

Tested with build-many-glibcs.py (host-libraries, compilers and glibcs
builds).
2020-10-30 17:16:54 +00:00
Carlos O'Donell
d598134bfb Argument Syntax: Use "option", @option, and @command.
Suggested-by: David O'Brien <daobrien@redhat.com>
2020-10-30 13:08:38 -04:00
Florian Weimer
de1a9197af elf: Unify old and new format cache handling code in ld.so
struct file_entry_new starts with the fields of struct file_entry,
so the code can be shared if the size computation is made dynamic.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2020-10-30 14:12:14 +01:00
Florian Weimer
cb3a749a22 x86: Restore processing of cache size tunables in init_cacheinfo
Fixes and partially reverts commit 59803e81f9
("x86: Optimizing memcpy for AMD Zen architecture.").
2020-10-28 15:53:26 +01:00
Érico Rolim
9538f6b95a Make elf.h header self contained.
The elf/elf.h header is shared, verbatim, by the elfutils project.
However, elfutils can be used on systems with libcs other than glibc,
making the presence of __BEGIN_DECLS, __END_DECLS and <features.h> in
the file something that downstream distros may have to add patches for.

Furthermore, this file doesn't declare anything with language linkage,
so `extern "C" {}` blocks aren't necessary; it also doesn't have any
conditional definitions based on feature test macros, making inclusion
of features.h unnecessary.
2020-10-28 11:29:16 +01:00
Sajan Karumanchi
59803e81f9 x86: Optimizing memcpy for AMD Zen architecture.
Modifying the shareable cache '__x86_shared_cache_size', which is a
factor in computing the non-temporal threshold parameter
'__x86_shared_non_temporal_threshold' to optimize memcpy for AMD Zen
architectures.
In the existing implementation, the shareable cache is computed as 'L3
per thread, L2 per core'. Recomputing this shareable cache as 'L3 per
CCX(Core-Complex)' has brought in performance gains.
As per the large bench variant results, this patch also addresses the
regression problem on AMD Zen architectures.

Reviewed-by: Premachandra Mallappa <premachandra.mallappa@amd.com>
2020-10-28 09:57:14 +01:00
Adhemerval Zanella
641a124845 Hurd: Fix ftime build
It does not provide __clock_gettime64, the ftime y2038 support is
moved to a Linux specific implementation.

Checked with a build for i686-linux-gnu and on x86_64-linux and
i686-linux-gnu.
2020-10-27 16:20:45 -03:00
Joseph Myers
b94cc191e0 Add IP_RECVERR_RFC4884 and IPV6_RECVERR_RFC4884 from Linux 5.9.
Add the new constants IP_RECVERR_RFC4884 and IPV6_RECVERR_RFC4884 from
Linux 5.9 to bits/in.h.

Tested for x86_64.
2020-10-27 17:42:34 +00:00
Florian Weimer
562ef5e69e misc: Add internal __getauxval2 function
The explicit error return value (without in-band signaling) avoids
complicated steps to detect errors based on whether errno has been
updated.

Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
2020-10-27 16:34:37 +01:00
Adhemerval Zanella
0ce51bef34 Remove NEWS entry about ftime removal
Now that it was reinstate with 30a0b167d3.
2020-10-27 10:43:37 -03:00
Adhemerval Zanella
5d8aa97da2 time: Add 64-bit time_t support for ftime
It basically calls the 64-bit __clock_gettime64 and adds the overflow
check.

Checked on x86_64-linux-gnu and i686-linux-gnu.

Reviewed-by: Lukasz Majewski <lukma@denx.de>
2020-10-27 09:54:50 -03:00
Adhemerval Zanella
30a0b167d3 Reinstate ftime and add deprecate message on ftime usage
This patch revert "Move ftime to a compatibility symbol" (commit
14633d3e56).

Checked on x86_64-linux-gnu and i686-linux-gnu.
2020-10-27 09:54:13 -03:00
Joseph Myers
6f21b0c5ed Update kernel version to 5.9 in tst-mman-consts.py.
This patch updates the kernel version in the test tst-mman-consts.py
to 5.9.  (There are no new MAP_* constants covered by this test in 5.9
that need any other header changes.)

Tested with build-many-glibcs.py.
2020-10-26 16:40:50 +00:00
Jonny Grant
0a3fce86ee Amend grammar and add a description
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2020-10-26 11:50:43 -04:00
Jonathan Wakely
ce643e6fe9 Fix typo in NEWS file 2020-10-26 11:46:00 +00:00
Stefan Liebler
9a29f1a2ae Remove timing related checks of time/tst-cpuclock1
Starting with the commit 04deeaa9ea
"Fix time/tst-cpuclock1 intermitent failures" (2020-07-11),
this test fails quite often on s390x/s390 with one/multiple of those:
"before - after" / "nanosleep time" / "dead - after" ourside reasonable range.

On a zVM/kvm guest the CPUs are shared between multiple guests.
And even on the lpar (kvm host) the CPUs are usually shared between multiple lpars.
The defined CPUs for a lpar/zVM-system could also have lower weights compared
to other lpars which let the steal time further grow.

Usually I build (-j$(nproc)) and test (PARALLELMFLAGS="-j$(nproc)") glibc multiple
times, e.g. with different GCCs, on various lpars or zVM guests at the same time.
During this time, I've run the test for 13500 times and obvserved the following fails:
~600x "before - after"
~60x "nanosleep time"
~70x "dead - after"

I've also observed a lot of "before - after" fails on a intel kvm-guest while
building/testing glibc on it.

The mentioned commit has tighten the limits of valid tv_nsec ranges:
"before - after" (expected: 500000000):
- 100000000 ... 600000000
+ 450000000 ... 550000000

"nanosleep time" (expected: 100000000):
- 100000000 ... 200000000
+ 090000000 ... 120000000

"dead - after" (expected: 100000000):
-           ... 200000000
+ 090000000 ... 120000000

The test itself forks a child process which chew_cpu (user- and kernel-space).
The parent process sleeps with nanosleep(0.5s) and measures the child_clock time:
diff = after - before
With much workload on the machine, the child won't make much progess
and it can fall much beyond the minimum limit.

Afterwards the parent process sleeps with clock_nanosleep (child_clock, 0.1s):
diff = afterns - after
The test currently also allows 0.9 * 0.1s which would be an error.
Depending on the workload, the maximum limit can exceed the 1.2 * 0.1s.

For "dead - after", the parent process kills the child process and waits long
enough to let the child finish dying. Then it gets the time of the child:
diff = dead - after
Note that diff also contains the time for the previous clock_nanosleep.
Thus you'll often see both fails at the same time.

After discussion on the mailing list, we've decided to keep the functional
checks for the clock* functions and remove the timing related checks as those
are prone to false positives.

Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2020-10-26 10:51:28 +01:00
Joseph Myers
dac8713629 Update syscall lists for Linux 5.9.
Linux 5.9 has one new syscall, close_range.  Update syscall-names.list
and regenerate the arch-syscall.h headers with build-many-glibcs.py
update-syscalls.

Tested with build-many-glibcs.py.
2020-10-23 16:31:11 +00:00
Joseph Myers
f603224706 Use Linux 5.9 in build-many-glibcs.py.
This patch makes build-many-glibcs.py use Linux 5.9.

Tested with build-many-glibcs.py (host-libraries, compilers and glibcs
builds).
2020-10-22 14:29:13 +00:00
Siddhesh Poyarekar
6c2b579962 Reword description of SXID_* tunable properties
The SXID_* tunable properties only influence processes that are
AT_SECURE, so make that a bit more explicit in the documentation and
comment.

Revisiting the code after a few years I managed to confuse myself, so
I imagine there could be others who may have incorrectly assumed like
I did that the SXID_ERASE tunables are not inherited by children of
non-AT_SECURE processes.

Reviewed-by: Florian Weimer <fweimer@redhat.com>
2020-10-22 13:52:38 +05:30
DJ Delorie
4be44c3208 New benchtest: pthread locks
Performance benchmarks for various posix locks: mutex, rwlock,
spinlock, condvar, and semaphore.  Each test is performed with
an empty loop body or with a computationally "interesting" (i.e.
difficult to optimize away, and used just to allow lock code to
be "hidden" in the filler's CPU cycles).
2020-10-21 11:03:52 -04:00
Lukasz Majewski
9cb2c92384 y2038: nptl: Provide __futex_clock_wait_bitset64 to support 64 bit bitset
The commit:
"y2038: nptl: Convert pthread_mutex_{clock|timed}lock to support 64 bit"
SHA1: 29e9874a04

introduced support for 64 bit timeouts. Unfortunately, it was missing the
code for bitset - i.e. lll_futex_clock_wait_bitset C preprocessor macro
was used. As a result the 64 bit struct __timespec64 was coerced to 32
bit struct timespec and regression visible as timeout was observed
(nptl/tst-robust10 on s390).

Reported-by: Stefan Liebler <stli@linux.ibm.com>
Tested-by: Stefan Liebler <stli@linux.ibm.com>
2020-10-21 11:43:35 +02:00
Cooper Qu
56b223c1c8 C-SKY: Make dynamic linker's name compitable with the older gcc.
__CSKY_HARD_FLOAT_ABI__ was added on gcc 11 to specify whether
-mfloat-abi=hard is set.  On older gcc, the float ABI is defined
solely with __CSKY_HARD_FLOAT__.  If __CSKY_HARD_FLOAT__ is set, it can
be either a hard-float ABI (gcc older than 11, or gcc11 -mfloat-abi=hard
(__CSKY_HARD_FLOAT_ABI__ is set) or -mfloat-abi=softfp
(__CSKY_HARD_FLOAT_ABI__ is not set). To be compatible with older gcc,
use __CSKY_HARD_FLOAT_FPU_SF__ identify if -mfloat-abi is supported,
because it is added to gcc at the same time as -mfloat-abi.

Reviewed-by: Mao Han  <han_mao@linux.alibaba.com>
Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2020-10-21 16:05:29 +08:00
Mao Han
33e5907ee6 Revert "C-SKY:Fix dynamic linker's name when mfloat-abi=softfp."
This reverts commit 7449320983.
2020-10-20 10:00:47 +08:00
Adhemerval Zanella
ab5ee31e14 Move vtimes to a compatibility symbol
I couldn't pinpoint which standard has added it, but no other POSIX
system supports it and/or no longer provide it.  The 'struct vtimes'
also has a lot of drawbacks due its limited internal type size.

I couldn't also see find any project that actually uses this symbol,
either in some dignostic way (such as sanitizer).  So I think it should
be safer to just move to compat symbol, instead of deprecated.  The
idea it to avoid new ports to export such broken interface (riscv32
for instance).

Checked on x86_64-linux-gnu and i686-linux-gnu.
2020-10-19 16:44:20 -03:00
Lukasz Majewski
75c4044b9a y2038: linux: Provide __time64 implementation
In the glibc the time function can use vDSO (on power and x86 the
USE_IFUNC_TIME is defined), time syscall or 'default' time() from
./time/time.c (as a fallback).

In this patch the last function (time) has been refactored and moved
to ./sysdeps/unix/sysv/linux/time.c to be Linux specific.

The new __time64 explicit 64 bit function for providing 64 bit value of
seconds after epoch (by internally calling __clock_gettime64) has been
introduced.

Moreover, a 32 bit version - __time has been refactored to internally
use __time64.

The __time is now supposed to be used on systems still supporting 32 bit
time (__TIMESIZE != 64) - hence the necessary check for time_t potential
overflow.

The iFUNC vDSO direct call optimization has been removed from both i686 and
powerpc32 (USE_IFUNC_TIME is not defined for those architectures
anymore). The Linux kernel does not provide a y2038 safe implementation of
time neither it plans to provide it in the future, __clock_gettime64
should be used instead. Keeping support for this optimization would require
to handle another build permutation (!__ASSUME_TIME64_SYSCALLS &&
USE_IFUNC_TIME which adds more complexity and has limited use (since the
idea is to eventually have a y2038 safe glibc build).

Build tests:
./src/scripts/build-many-glibcs.py glibcs

Run-time tests:
- Run specific tests on ARM/x86 32bit systems (qemu):
https://github.com/lmajewski/meta-y2038 and run tests:
https://github.com/lmajewski/y2038-tests/commits/master

Above tests were performed with Y2038 redirection applied as well as
without to test proper usage of both __time64 and __time.

Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
2020-10-19 16:01:37 +02:00
Jonny Grant
0e6ee9c143 rt: Fix typos in comments in <aio.h> 2020-10-19 10:55:00 +02:00
Cooper Qu
7449320983 C-SKY:Fix dynamic linker's name when mfloat-abi=softfp.
The dynamic linker should be chosen according to float abi, the
predefined macro __CSKY_HARD_FLOAT__ stand for architecure not
abi.

Reviewed-by: Mao Han <han_mao@linux.alibaba.com>
2020-10-19 12:48:37 +08:00
H.J. Lu
0f09154c64 x86: Initialize CPU info via IFUNC relocation [BZ 26203]
X86 CPU features in ld.so are initialized by init_cpu_features, which is
invoked by DL_PLATFORM_INIT from _dl_sysdep_start.  But when ld.so is
loaded by static executable, DL_PLATFORM_INIT is never called.  Also
x86 cache info in libc.o and libc.a is initialized by a constructor
which may be called too late.  Since some fields in _rtld_global_ro
in ld.so are initialized by dynamic relocation, we can also initialize
x86 CPU features in _rtld_global_ro in ld.so and cache info in libc.so
by initializing dummy function pointers in ld.so and libc.so via IFUNC
relocation.

Key points:

1. IFUNC is always supported, independent of --enable-multi-arch or
--disable-multi-arch.  Linker generates IFUNC relocations from input
IFUNC objects and ld.so performs IFUNC relocations.
2. There are no IFUNC dependencies in ld.so before dynamic relocation
have been performed,
3. The x86 CPU features in ld.so is initialized by DL_PLATFORM_INIT
in dynamic executable and by IFUNC relocation in dlopen in static
executable.
4. The x86 cache info in libc.o is initialized by IFUNC relocation.
5. In libc.a, both x86 CPU features and cache info are initialized from
ARCH_INIT_CPU_FEATURES, not by IFUNC relocation, before __libc_early_init
is called.

Note: _dl_x86_init_cpu_features can be called more than once from
DL_PLATFORM_INIT and during relocation in ld.so.
2020-10-16 16:17:53 -07:00
Adhemerval Zanella
d6fa317099 Add NEWS entry for ftime compatibility move 2020-10-16 15:16:06 -03:00