Commit Graph

38273 Commits

Author SHA1 Message Date
H.J. Lu
ceeffe968c x86: Don't set Prefer_No_AVX512 for processors with AVX512 and AVX-VNNI
Don't set Prefer_No_AVX512 on processors with AVX512 and AVX-VNNI since
they won't lower CPU frequency when ZMM load and store instructions are
used.
2021-12-06 07:14:12 -08:00
Adhemerval Zanella
a329f68f2e linux: Add generic ioctl implementation
The powerpc is refactor to use the default implementation.
2021-12-06 08:03:18 -03:00
Adhemerval Zanella
00baddbb93 linux: Add generic syscall implementation
It allows also to remove hppa specific implementation and simplify
riscv implementation a bit.
2021-12-06 08:03:11 -03:00
Florian Weimer
68007900be misc, nptl: Remove stray references to __condvar_load_64_relaxed
The function was renamed to __atomic_wide_counter_load_relaxed
in commit 8bd336a00a ("nptl: Extract
<bits/atomic_wide_counter.h> from pthread_cond_common.c").
2021-12-06 08:01:08 +01:00
Florian Weimer
4fb4e7e821 csu: Always use __executable_start in gmon-start.c
Current binutils defines __executable_start as the lowest text
address, so using the entry point address as a fallback is no
longer necessary.  As a result, overriding <entry.h> is only
necessary if the entry point is not called _start.

The previous approach to define __ASSEMBLY__ to suppress the
declaration breaks if headers included by <entry.h> are not
compatible with __ASSEMBLY__.  This happens with rseq integration
because it is necessary to include kernel headers in more places.

Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
2021-12-05 13:50:21 +01:00
Florian Weimer
c1cb2deeca elf: execve statically linked programs instead of crashing [BZ #28648]
Programs without dynamic dependencies and without a program
interpreter are now run via execve.

Previously, the dynamic linker either crashed while attempting to
read a non-existing dynamic segment (looking for DT_AUDIT/DT_DEPAUDIT
data), or the self-relocated in the static PIE executable crashed
because the outer dynamic linker had already applied RELRO protection.

<dl-execve.h> is needed because execve is not available in the
dynamic loader on Hurd.

Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
2021-12-05 11:28:34 +01:00
H.J. Lu
bada2e312a Add --with-timeoutfactor=NUM to specify TIMEOUTFACTOR
On Ice Lake and Tiger Lake laptops, some test programs timeout when there
are 3 "make check -j8" runs in parallel.  Add --with-timeoutfactor=NUM to
specify an integer to scale the timeout of test programs, which can be
overriden by TIMEOUTFACTOR environment variable.

Reviewed-by: Florian Weimer <fweimer@redhat.com>
2021-12-04 12:58:28 -08:00
Noah Goldstein
4df1fa6ddc x86-64: Use notl in EVEX strcmp [BZ #28646]
Must use notl %edi here as lower bits are for CHAR comparisons
potentially out of range thus can be 0 without indicating mismatch.
This fixes BZ #28646.

Co-Authored-By: H.J. Lu <hjl.tools@gmail.com>
2021-12-03 21:14:11 -08:00
Florian Weimer
23c77f6018 nptl: Increase default TCB alignment to 32
rseq support will use a 32-byte aligned field in struct pthread,
so the whole struct needs to have at least that alignment.

nptl/tst-tls3mod.c uses TCB_ALIGNMENT, therefore include <descr.h>
to obtain the fallback definition.

Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
2021-12-03 20:43:31 +01:00
Luca Boccassi
0656b649c5 elf: add definition for ELF_NOTE_FDO and NT_FDO_PACKAGING_METADATA note
As defined on: https://systemd.io/COREDUMP_PACKAGE_METADATA/
this note will be used starting from Fedora 36.

Signed-off-by: Luca Boccassi <bluca@debian.org>
2021-12-02 23:01:51 +01:00
Wilco Dijkstra
b31bd11454 AArch64: Improve A64FX memcpy
v2 is a complete rewrite of the A64FX memcpy. Performance is improved
by streamlining the code, aligning all large copies and using a single
unrolled loop for all sizes. The code size for memcpy and memmove goes
down from 1796 bytes to 868 bytes. Performance is better in all cases:
bench-memcpy-random is 2.3% faster overall, bench-memcpy-large is ~33%
faster for large sizes, bench-memcpy-walk is 25% faster for small sizes
and 20% for the largest sizes. The geomean of all tests in bench-memcpy
is 5.1% faster, and total time is reduced by 4%.

Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
2021-12-02 18:36:03 +00:00
Wilco Dijkstra
b51eb35c57 AArch64: Optimize memcmp
Rewrite memcmp to improve performance. On small and medium inputs performance
is 10-20% better. Large inputs use a SIMD loop processing 64 bytes per
iteration, which is 30-50% faster depending on the size.

Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
2021-12-02 18:35:53 +00:00
Matheus Castanho
d120fb9941 powerpc64[le]: Fix CFI and LR save address for asm syscalls [BZ #28532]
Syscalls based on the assembly templates are missing CFI for r31, which gets
clobbered when scv is used, and info for LR is inaccurate, placed in the wrong
LOC and not using the proper offset. LR was also being saved to the callee's
frame, while the ABI mandates it to be saved to the caller's frame. These are
fixed by this commit.

After this change:

$ readelf -wF libc.so.6 | grep 0004b9d4.. -A 7 && objdump --disassemble=kill libc.so.6
00004a48 0000000000000020 00004a4c FDE cie=00000000 pc=000000000004b9d4..000000000004ba3c
   LOC           CFA      r31   ra
000000000004b9d4 r1+0     u     u
000000000004b9e4 r1+48    u     u
000000000004b9e8 r1+48    c-16  u
000000000004b9fc r1+48    c-16  c+16
000000000004ba08 r1+48    c-16
000000000004ba18 r1+48    u
000000000004ba1c r1+0     u

libc.so.6:     file format elf64-powerpcle

Disassembly of section .text:

000000000004b9d4 <kill>:
   4b9d4:       1f 00 4c 3c     addis   r2,r12,31
   4b9d8:       2c c3 42 38     addi    r2,r2,-15572
   4b9dc:       25 00 00 38     li      r0,37
   4b9e0:       d1 ff 21 f8     stdu    r1,-48(r1)
   4b9e4:       20 00 e1 fb     std     r31,32(r1)
   4b9e8:       98 8f ed eb     ld      r31,-28776(r13)
   4b9ec:       10 00 ff 77     andis.  r31,r31,16
   4b9f0:       1c 00 82 41     beq     4ba0c <kill+0x38>
   4b9f4:       a6 02 28 7d     mflr    r9
   4b9f8:       40 00 21 f9     std     r9,64(r1)
   4b9fc:       01 00 00 44     scv     0
   4ba00:       40 00 21 e9     ld      r9,64(r1)
   4ba04:       a6 03 28 7d     mtlr    r9
   4ba08:       08 00 00 48     b       4ba10 <kill+0x3c>
   4ba0c:       02 00 00 44     sc
   4ba10:       00 00 bf 2e     cmpdi   cr5,r31,0
   4ba14:       20 00 e1 eb     ld      r31,32(r1)
   4ba18:       30 00 21 38     addi    r1,r1,48
   4ba1c:       18 00 96 41     beq     cr5,4ba34 <kill+0x60>
   4ba20:       01 f0 20 39     li      r9,-4095
   4ba24:       40 48 23 7c     cmpld   r3,r9
   4ba28:       20 00 e0 4d     bltlr+
   4ba2c:       d0 00 63 7c     neg     r3,r3
   4ba30:       08 00 00 48     b       4ba38 <kill+0x64>
   4ba34:       20 00 e3 4c     bnslr+
   4ba38:       c8 32 fe 4b     b       2ed00 <__syscall_error>
        ...
   4ba44:       40 20 0c 00     .long 0xc2040
   4ba48:       68 00 00 00     .long 0x68
   4ba4c:       06 00 5f 5f     rlwnm   r31,r26,r0,0,3
   4ba50:       6b 69 6c 6c     xoris   r12,r3,26987
2021-11-30 15:18:52 -03:00
Adhemerval Zanella
efc6b2dbc4 linux: Implement pipe in terms of __NR_pipe2
The syscall pipe2 was added in linux 2.6.27 and glibc requires linux
3.2.0.  The patch removes the arch-specific implementation for alpha,
ia64, mips, sh, and sparc which requires a different kernel ABI
than the usual one.

Checked on x86_64-linux-gnu and with a build for the affected ABIs.
2021-11-30 13:13:03 -03:00
Adhemerval Zanella
5b3e31e312 linux: Implement mremap in C
Variadic function calls in syscalls.list does not work for all ABIs
(for instance where the argument are passed on the stack instead of
registers) and might have underlying issues depending of the variadic
type (for instance if a 64-bit argument is used).

Checked on x86_64-linux-gnu.
2021-11-30 13:13:03 -03:00
Adhemerval Zanella
83008fa495 linux: Add prlimit64 C implementation
The LFS prlimit64 requires a arch-specific implementation in
syscalls.list.  Instead add a generic one that handles the
required symbol alias for __RLIM_T_MATCHES_RLIM64_T.

HPPA is the only outlier which requires a different default
symbol.

Checked on x86_64-linux-gnu and with build for the affected ABIs.
2021-11-30 13:13:03 -03:00
Florian Weimer
df4cb2280e elf: Include <stdbool.h> in tst-tls20.c
The test uses the bool type.
2021-11-30 15:39:17 +01:00
Florian Weimer
3c7c511782 elf: Include <stdint.h> in tst-tls20.c
The test uses standard integer types.
2021-11-30 14:35:54 +01:00
Samuel Thibault
e49c3c5d7a hurd: Let report-wait use a weak reference to _hurd_itimer_thread
libc.so.0.3 does not seem to need this defined any more.
2021-11-28 21:26:25 +01:00
Adhemerval Zanella
137ed5ac44 linux: Use /proc/stat fallback for __get_nprocs_conf (BZ #28624)
The /proc/statm fallback was removed by f13fb81ad3 if sysfs is
not available, reinstate it.

Checked on x86_64-linux-gnu.
2021-11-25 11:00:42 -03:00
Adhemerval Zanella
d150181d73 linux: Add fanotify_mark C implementation
Passing 64-bit arguments on syscalls.list is tricky: it requires
to reimplement the expected kernel abi in each architecture.  This
is way to better to represent in C code where we already have
macros for this (SYSCALL_LL64).

Checked on x86_64-linux-gnu.
2021-11-25 09:56:57 -03:00
Adhemerval Zanella
c3b023a782 linux: Only build fstatat fallback if required
For 32-bit architecture with __ASSUME_STATX there is no need to
build fstatat64_time64_stat.

Checked on i686-linux-gnu.
2021-11-25 09:28:27 -03:00
Paul Eggert
c52ef24829 regex: fix buffer read overrun in search [BZ#28470]
Problem reported by Benno Schulenberg in:
https://lists.gnu.org/r/bug-gnulib/2021-10/msg00035.html
* posix/regexec.c (re_search_internal): Use better bounds check.
2021-11-24 14:16:09 -08:00
Sunil K Pandey
c58d3b7d00 x86-64: Add vector sin/sinf to libmvec microbenchmark
Add vector sin/sinf and input files to libmvec microbenchmark.

libmvec-sin-inputs:
  90% Normal random distribution
  range: (-DBL_MAX, DBL_MAX)
  mean: 0.0
  sigma: 5.0
  10% uniform random distribution in range (-1000.0, 1000.0)

libmvec-sinf-inputs:
  90% Normal random distribution
  range: (-FLT_MAX, FLT_MAX)
  mean: 0.0f
  sigma: 5.0f
  10% uniform random distribution in range (-1000.0f, 1000.0f)

Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
2021-11-24 07:50:23 -08:00
Sunil K Pandey
6a556bac81 x86-64: Add vector pow/powf to libmvec microbenchmark
Add vector pow/powf and input files to libmvec microbenchmark.

libmvec-pow-inputs:
  arg1:
    90% Normal random distribution
    range: (0.0, 256.0)
    mean: 0.0
    sigma: 32.0
    10% uniform random distribution in range (0.0, 256.0)
  arg2:
    90% Normal random distribution
    range: (-127.0, 127.0)
    mean: 0.0
    sigma: 16.0
    10% uniform random distribution in range (-127.0, 127.0)

libmvec-powf-inputs:
  arg1:
    90% Normal random distribution
    range: (0.0f, 100.0f)
    mean: 0.0f
    sigma: 16.0f
    10% uniform random distribution in range (0.0f, 100.0f)
  arg2:
    90% Normal random distribution
    range: (-10.0f, 10.0f)
    mean: 0.0f
    sigma: 8.0f
    10% uniform random distribution in range (-10.0f, 10.0f)

Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
2021-11-24 07:49:14 -08:00
Sunil K Pandey
8ab8afb336 x86-64: Add vector log/logf to libmvec microbenchmark
Add vector log/logf and input files to libmvec microbenchmark.

libmvec-log-inputs:
  70% Normal random distribution
  range: (0.0, DBL_MAX)
  mean: 1.0
  sigma: 50.0
  30% uniform random distribution in range (0.0, DBL_MAX)

libmvec-logf-inputs:
  70% Normal random distribution
  range: (0.0f, FLT_MAX)
  mean: 1.0f
  sigma: 50.0f
  30% uniform random distribution in range (0.0f, FLT_MAX)

Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
2021-11-24 07:48:14 -08:00
Sunil K Pandey
37df38bd5f x86-64: Add vector exp/expf to libmvec microbenchmark
Add vector exp/expf and input files to libmvec microbenchmark.

libmvec-exp-inputs:
  90% Normal random distribution
  range: (-708.0, 709.0)
  mean: 0.0
  sigma: 16.0
  10% uniform random distribution in range (-500.0, 500.0)

libmvec-expf-inputs:
  90% Normal random distribution
  range: (-87.0f, 88.0f)
  mean: 0.0f
  sigma: 8.0f
  10% uniform random distribution in range (-50.0f, 50.0f)

Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
2021-11-24 07:46:59 -08:00
Sunil K Pandey
4443695598 x86-64: Add vector cos/cosf to libmvec microbenchmark
Add vector cos/cosf and input files to libmvec microbenchmark.

libmvec-cos-inputs:
  90% Normal random distribution
  range: (-DBL_MAX, DBL_MAX)
  mean: 0.0
  sigma: 5.0
  10% uniform random distribution in range (-1000.0, 1000.0)

libmvec-cosf-inputs:
  90% Normal random distribution
  range: (-FLT_MAX, FLT_MAX)
  mean: 0.0f
  sigma: 5.0f
  10% uniform random distribution in range (-1000.0f, 1000.0f)

Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
2021-11-24 07:45:20 -08:00
Adhemerval Zanella
456b3c08b6 io: Refactor close_range and closefrom
Now that Hurd implementis both close_range and closefrom (f2c996597d),
we can make close_range() a base ABI, and make the default closefrom()
implementation on top of close_range().

The generic closefrom() implementation based on __getdtablesize() is
moved to generic close_range().  On Linux it will be overriden by
the auto-generation syscall while on Hurd it will be a system specific
implementation.

The closefrom() now calls close_range() and __closefrom_fallback().
Since on Hurd close_range() does not fail, __closefrom_fallback() is an
empty static inline function set by__ASSUME_CLOSE_RANGE.

The __ASSUME_CLOSE_RANGE also allows optimize Linux
__closefrom_fallback() implementation when --enable-kernel=5.9 or
higher is used.

Finally the Linux specific tst-close_range.c is moved to io and
enabled as default.  The Linuxism and CLOSE_RANGE_UNSHARE are
guarded so it can be built for Hurd (I have not actually test it).

Checked on x86_64-linux-gnu, i686-linux-gnu, and with a i686-gnu
build.
2021-11-24 09:09:37 -03:00
Florian Weimer
e186fc5a31 nptl: Do not set signal mask on second setjmp return [BZ #28607]
__libc_signal_restore_set was in the wrong place: It also ran
when setjmp returned the second time (after pthread_exit or
pthread_cancel).  This is observable with blocked pending
signals during thread exit.

Fixes commit b3cae39dcb
("nptl: Start new threads with all signals blocked [BZ #25098]").

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2021-11-24 08:59:54 +01:00
Adhemerval Zanella
aac54dcd37 powerpc: Define USE_PPC64_NOTOC iff compiler supports it
The @notoc usage only yields an advantage on ISA 3.1+ machine (power10)
and for ld.bfd also when it sees pcrel relocations used on the code
(generated if compiler targets ISA 3.1+).  On bfd case ISA 3.1+
instruction on stubs are used iff linker also sees the new pc-relative
relocations (for instance R_PPC64_D34), otherwise it generates default
stubs (ppc64_elf_check_relocs:4700).

This patch also help on linkers that do not implement this optimization,
since building for older ISA (such as 3.0 / power9) will also trigger
power10 stubs generation in the assembly code uses the NOTOC imacro.

Checked on powerpc64le-linux-gnu.

Reviewed-by: Fangrui Song <maskray@google.com>
Reviewed-by: Tulio Magno Quites Machado Filho <tuliom@linux.ibm.com>
2021-11-22 14:49:11 -03:00
Adhemerval Zanella
bc801b3a40 setjmp: Replace jmp_buf-macros.h with jmp_buf-macros.sym
It requires less boilerplate code for newer ports.  The _Static_assert
checks from internal setjmp are moved to its own internal test since
setjmp.h is included early by multiple headers (to generate
rtld-sizes.sym).

The riscv jmp_buf-macros.h check is also redundant, it is already
done by riscv configure.ac.

Checked with a build for the affected architectures.
2021-11-22 13:43:22 -03:00
Joseph Myers
5c3ece451d Update kernel version to 5.15 in tst-mman-consts.py
This patch updates the kernel version in the test tst-mman-consts.py
to 5.15.  (There are no new MAP_* constants covered by this test in
5.15 that need any other header changes.)

Tested with build-many-glibcs.py.
2021-11-22 15:30:12 +00:00
Florian Weimer
3d981795cd socket: Do not use AF_NETLINK in __opensock
It is not possible to use interface ioctls with netlink sockets
on all Linux kernels.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2021-11-22 14:47:13 +01:00
Adhemerval Zanella
ed3ce71f5c elf: Move la_activity (LA_ACT_ADD) after _dl_add_to_namespace_list() (BZ #28062)
It ensures that the the namespace is guaranteed to not be empty.

Checked on x86_64-linux-gnu.

Reviewed-by: Florian Weimer <fweimer@redhat.com>
2021-11-18 17:17:58 -03:00
Joseph Myers
bdeb7a8fa9 Add PF_MCTP, AF_MCTP from Linux 5.15 to bits/socket.h
Linux 5.15 adds a new address / protocol family PF_MCTP / AF_MCTP; add
these constants to bits/socket.h.

Tested for x86_64.
2021-11-17 14:25:16 +00:00
Stafford Horne
f1bcfde3a7 malloc: Fix malloc debug for 2.35 onwards
The change 1e5a5866cb ("Remove malloc hooks [BZ #23328]") has broken
ports that are using GLIBC_2_35, like the new OpenRISC port I am working
on.

The libc_malloc_debug.so library used to bring in the debug
infrastructure is currently essentially empty for GLIBC_2_35 ports like
mine causing mtrace tests to fail:

    cat sysdeps/unix/sysv/linux/or1k/shlib-versions
    DEFAULT                 GLIBC_2.35
    ld=ld-linux-or1k.so.1

    FAIL: posix/bug-glob2-mem
    FAIL: posix/bug-regex14-mem
    FAIL: posix/bug-regex2-mem
    FAIL: posix/bug-regex21-mem
    FAIL: posix/bug-regex31-mem
    FAIL: posix/bug-regex36-mem
    FAIL: malloc/tst-mtrace.

The issue seems to be with the ifdefs in malloc/malloc-debug.c. The
ifdefs are currently essentially exluding all symbols for ports > 2.35.

Removing the top level SHLIB_COMPAT ifdef allows things to just work.

Fixes: 1e5a5866cb ("Remove malloc hooks [BZ #23328]")
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
2021-11-17 21:33:39 +09:00
Florian Weimer
f1d333b5bf elf: Introduce GLRO (dl_libc_freeres), called from __libc_freeres
This will be used to deallocate memory allocated using the non-minimal
malloc.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2021-11-17 12:20:29 +01:00
Florian Weimer
8bd336a00a nptl: Extract <bits/atomic_wide_counter.h> from pthread_cond_common.c
And make it an installed header.  This addresses a few aliasing
violations (which do not seem to result in miscompilation due to
the use of atomics), and also enables use of wide counters in other
parts of the library.

The debug output in nptl/tst-cond22 has been adjusted to print
the 32-bit values instead because it avoids a big-endian/little-endian
difference.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2021-11-17 12:20:13 +01:00
Sunil K Pandey
a43c0b5483 x86-64: Create microbenchmark infrastructure for libmvec
Add python script to generate libmvec microbenchmark from the input
values for each libmvec function using skeleton benchmark template.

Creates double and float benchmarks with vector length 1, 2, 4, 8,
and 16 for each libmvec function.  Vector length 1 corresponds to
scalar version of function and is included for vector function perf
comparison.

Co-authored-by: Haochen Jiang <haochen.jiang@intel.com>
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
2021-11-16 11:37:39 -08:00
Adhemerval Zanella
d8c2e8e043 elf: hidden visibility for __minimal_malloc functions
Since b05fae4d8e, __minimal malloc code is used during static
startup before PIE self-relocation (_dl_relocate_static_pie).
So it requires the same fix done for other objects by 47618209d0.

Checked on aarch64, x86_64, and i686 with and without static-pie.
2021-11-16 16:03:31 -03:00
H.J. Lu
1f67d8286b elf: Use a temporary file to generate Makefile fragments [BZ #28550]
1. Use a temporary file to generate Makefile fragments for DSO sorting
tests and use -include on them.
2. Add Makefile fragments to postclean-generated so that a "make clean"
removes the autogenerated fragments and a subsequent "make" regenerates
them.

This partially fixes BZ #28550.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2021-11-16 05:18:01 -08:00
H.J. Lu
b4bbedb1e7 dso-ordering-test.py: Put all sources in one directory [BZ #28550]
Put all sources for DSO sorting tests in the dso-sort-tests-src directory
and compile test relocatable objects with

$(objpfx)tst-dso-ordering1-dir/tst-dso-ordering1-a.os: $(objpfx)dso-sort-tests-src/tst-dso-ordering1-a.c
	$(compile.c) $(OUTPUT_OPTION)

to avoid random $< values from $(before-compile) when compiling test
relocatable objects with

$(objpfx)%$o: $(objpfx)%.c $(before-compile); $$(compile-command.c)
compile-command.c = $(compile.c) $(OUTPUT_OPTION) $(compile-mkdep-flags)
compile.c = $(CC) $< -c $(CFLAGS) $(CPPFLAGS)

for 3 "make -j 28" parallel builds on a machine with 112 cores at the
same time.

This partially fixes BZ #28550.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2021-11-15 11:53:40 -08:00
Adhemerval Zanella
54816ae98d elf: Move LAV_CURRENT to link_lavcurrent.h
No functional change.
2021-11-15 15:28:17 -03:00
H.J. Lu
120ac6d238 Move assignment out of the CAS condition
Update

commit 49302b8fdf
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Thu Nov 11 06:54:01 2021 -0800

    Avoid extra load with CAS in __pthread_mutex_clocklock_common [BZ #28537]

    Replace boolean CAS with value CAS to avoid the extra load.

and

commit 0b82747dc4
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Thu Nov 11 06:31:51 2021 -0800

    Avoid extra load with CAS in __pthread_mutex_lock_full [BZ #28537]

    Replace boolean CAS with value CAS to avoid the extra load.

by moving assignment out of the CAS condition.
2021-11-15 05:50:56 -08:00
H.J. Lu
cbcd65c8b5 Add a comment for --enable-initfini-array [BZ #27945]
Document that --enable-initfini-array is enabled by default in GCC 12,
which can be removed when GCC 12 becomes the minimum requirement.
2021-11-13 09:50:07 -08:00
Stafford Horne
afbf26492a tst-tzset: output reason when creating 4GiB file fails
Currently, if the temporary file creation fails the create_tz_file
function returns NULL.  The NULL pointer is then passed to setenv which
causes a SIGSEGV.  Rather than failing with a SIGSEGV print a warning
and exit.
2021-11-13 08:08:47 +09:00
H.J. Lu
d672a98a1a Add LLL_MUTEX_READ_LOCK [BZ #28537]
CAS instruction is expensive.  From the x86 CPU's point of view, getting
a cache line for writing is more expensive than reading.  See Appendix
A.2 Spinlock in:

https://www.intel.com/content/dam/www/public/us/en/documents/white-papers/xeon-lock-scaling-analysis-paper.pdf

The full compare and swap will grab the cache line exclusive and cause
excessive cache line bouncing.

Add LLL_MUTEX_READ_LOCK to do an atomic load and skip CAS in spinlock
loop if compare may fail to reduce cache line bouncing on contended locks.

Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
2021-11-12 10:32:09 -08:00
H.J. Lu
49302b8fdf Avoid extra load with CAS in __pthread_mutex_clocklock_common [BZ #28537]
Replace boolean CAS with value CAS to avoid the extra load.

Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
2021-11-12 10:31:31 -08:00
H.J. Lu
0b82747dc4 Avoid extra load with CAS in __pthread_mutex_lock_full [BZ #28537]
Replace boolean CAS with value CAS to avoid the extra load.

Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
2021-11-12 10:30:57 -08:00