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18 Commits

Author SHA1 Message Date
Uros Bizjak
b8253693b7 x86: Define atomic_compare_and_exchange_{val, bool}_acq using __atomic_compare_exchange_n 
No functional changes.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: Adhemerval Zanella Netto <adhemerval.zanella@linaro.org>
Cc: Wilco Dijkstra <Wilco.Dijkstra@arm.com>
Cc: Collin Funk <collin.funk1@gmail.com>
Cc: H.J.Lu <hjl.tools@gmail.com>
Cc: Carlos O'Donell <carlos@redhat.com>
Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
 2025-09-09 07:58:52 -07:00
Uros Bizjak
935ee691bc x86: Define atomic_exchange_acq using __atomic_exchange_n 
The resulting libc.so is identical on both x86_64 and
i386 targets compared to unpatched builds:

$ sha1sum libc-x86_64-old.so libc-x86_64-new.so
74eca1b87f2ecc9757a984c089a582b7615d93e7  libc-x86_64-old.so
74eca1b87f2ecc9757a984c089a582b7615d93e7  libc-x86_64-new.so
$ sha1sum libc-i386-old.so libc-i386-new.so
882bbab8324f79f4fbc85224c4c914fc6822ece7  libc-i386-old.so
882bbab8324f79f4fbc85224c4c914fc6822ece7  libc-i386-new.so

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: Adhemerval Zanella Netto <adhemerval.zanella@linaro.org>
Cc: Wilco Dijkstra <Wilco.Dijkstra@arm.com>
Cc: Collin Funk <collin.funk1@gmail.com>
Cc: H.J.Lu <hjl.tools@gmail.com>
Cc: Carlos O'Donell <carlos@redhat.com>
Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
 2025-09-09 07:51:41 -07:00
Uros Bizjak
e6b5ad1b1d x86: Define atomic_full_barrier using __sync_synchronize 
For x86_64 targets, __sync_synchronize emits a full 64-bit
'LOCK ORQ $0x0,(%rsp)' instead of 'LOCK ORL $0x0,(%rsp)'.

No functional changes.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: Adhemerval Zanella Netto <adhemerval.zanella@linaro.org>
Cc: Wilco Dijkstra <Wilco.Dijkstra@arm.com>
Cc: Collin Funk <collin.funk1@gmail.com>
Cc: H.J.Lu <hjl.tools@gmail.com>
Cc: Carlos O'Donell <carlos@redhat.com>
Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
 2025-09-09 07:44:41 -07:00
Uros Bizjak
4eef002328 x86: Remove catomic_* locking primitives 
Remove obsolete catomic_* locking primitives which don't map
to standard compiler builtins.

There are still a couple of places in the tree that uses them
(malloc/arena.c and malloc/malloc.c).

x86 didn't define __arch_c_compare_and_exchange_bool_* primitives
so fallback code used __arch_c_compare_and_exchange_val_* primitives
instead.  This resulted in unoptimal code for
catomic_compare_and_exchange_bool_acq where superfluous
CMP was emitted after CMPXCHG, e.g. in arena_get2:

   775b8:	48 8d 4a 01          	lea    0x1(%rdx),%rcx
   775bc:	48 89 d0             	mov    %rdx,%rax
   775bf:	64 83 3c 25 18 00 00 	cmpl   $0x0,%fs:0x18
   775c6:	00 00
   775c8:	74 01                	je     775cb <arena_get2+0x35b>
   775ca:	f0 48 0f b1 0d 75 3d 	lock cmpxchg %rcx,0x163d75(%rip)        # 1db348 <narenas>
   775d1:	16 00
   775d3:	48 39 c2             	cmp    %rax,%rdx
   775d6:	74 7f                	je     77657 <arena_get2+0x3e7>

that now becomes:

   775b8:	48 8d 4a 01          	lea    0x1(%rdx),%rcx
   775bc:	48 89 d0             	mov    %rdx,%rax
   775bf:	f0 48 0f b1 0d 80 3d 	lock cmpxchg %rcx,0x163d80(%rip)        # 1db348 <narenas>
   775c6:	16 00
   775c8:	74 7f                	je     77649 <arena_get2+0x3d9>

OTOH, catomic_decrement does not fallback to atomic_fetch_add (, -1)
builtin but to the cmpxchg loop, so the generated code in arena_get2
regresses a bit, from using LOCK DECQ insn:

   77829:	64 83 3c 25 18 00 00 	cmpl   $0x0,%fs:0x18
   77830:	00 00
   77832:	74 01                	je     77835 <arena_get2+0x5c5>
   77834:	f0 48 ff 0d 0c 3b 16 	lock decq 0x163b0c(%rip)        # 1db348 <narenas>
   7783b:	00

to a cmpxchg loop:

   7783d:	48 8b 0d 04 3b 16 00 	mov    0x163b04(%rip),%rcx        # 1db348 <narenas>
   77844:	48 8d 71 ff          	lea    -0x1(%rcx),%rsi
   77848:	48 89 c8             	mov    %rcx,%rax
   7784b:	f0 48 0f b1 35 f4 3a 	lock cmpxchg %rsi,0x163af4(%rip)        # 1db348 <narenas>
   77852:	16 00
   77854:	0f 84 c9 fa ff ff    	je     77323 <arena_get2+0xb3>
   7785a:	eb e1                	jmp    7783d <arena_get2+0x5cd>

Defining catomic_exchange_and_add using __atomic_fetch_add solves the
above issue and generates optimal:

   77809:	f0 48 83 2d 36 3b 16 	lock subq $0x1,0x163b36(%rip)        # 1db348 <narenas>
   77810:	00 01

Depending on the target processor, the compiler may emit either
'LOCK ADD/SUB $1, m' or 'INC/DEC $1, m' instruction, due to partial
flag register stall issue.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: Adhemerval Zanella Netto <adhemerval.zanella@linaro.org>
Cc: Wilco Dijkstra <Wilco.Dijkstra@arm.com>
Cc: Collin Funk <collin.funk1@gmail.com>
Cc: H.J.Lu <hjl.tools@gmail.com>
Cc: Carlos O'Donell <carlos@redhat.com>
Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
 2025-09-09 07:36:02 -07:00
Uros Bizjak
af5b01dc26 x86: Remove unused atomics 
Remove unused atomics from <sysdeps/x86/atomic-machine.h>.

The resulting libc.so is identical on both x86_64 and
i386 targets compared to unpatched builds:

$ sha1sum libc-x86_64-old.so libc-x86_64-new.so
b89aaa2b71efd435104ebe6f4cd0f2ef89fcac90  libc-x86_64-old.so
b89aaa2b71efd435104ebe6f4cd0f2ef89fcac90  libc-x86_64-new.so
$ sha1sum libc-i386-old.so libc-i386-new.so
aa70f2d64da2f0f516634b116014cfe7af3e5b1a  libc-i386-old.so
aa70f2d64da2f0f516634b116014cfe7af3e5b1a  libc-i386-new.so

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: Adhemerval Zanella Netto <adhemerval.zanella@linaro.org>
Cc: Wilco Dijkstra <Wilco.Dijkstra@arm.com>
Cc: Collin Funk <collin.funk1@gmail.com>
Cc: H.J.Lu <hjl.tools@gmail.com>
Cc: Carlos O'Donell <carlos@redhat.com>
Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
 2025-09-09 07:29:57 -07:00
Uros Bizjak
119d658ac2 x86: Use flag output operands for inline asm in atomic-machine.h 
Use the flag output constraints feature available in gcc 6+
("=@cc<cond>") instead of explicitly setting a boolean variable
with SETcc instruction.  This approach decouples the instruction
that sets the flags from the code that consumes them, allowing
the compiler to create better code when working with flags users.
Instead of e.g.:

   lock add %esi,(%rdi)
   sets   %sil
   test   %sil,%sil
   jne    <...>

the compiler now generates:

   lock add %esi,(%rdi)
   js     <...>

No functional changes intended.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Cc: H.J.Lu <hjl.tools@gmail.com>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: Carlos O'Donell <carlos@redhat.com>
Reviewed-by: Florian Weimer <fweimer@redhat.com>
 2025-08-29 09:05:23 +02:00
Paul Eggert
2642002380 Update copyright dates with scripts/update-copyrights 2025-01-01 11:22:09 -08:00
Paul Eggert
dff8da6b3e Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
Joseph Myers
6d7e8eda9b Update copyright dates with scripts/update-copyrights 2023-01-06 21:14:39 +00:00
Paul Eggert
581c785bf3 Update copyright dates with scripts/update-copyrights 
I used these shell commands:

../glibc/scripts/update-copyrights $PWD/../gnulib/build-aux/update-copyright
(cd ../glibc && git commit -am"[this commit message]")

and then ignored the output, which consisted lines saying "FOO: warning:
copyright statement not found" for each of 7061 files FOO.

I then removed trailing white space from math/tgmath.h,
support/tst-support-open-dev-null-range.c, and
sysdeps/x86_64/multiarch/strlen-vec.S, to work around the following
obscure pre-commit check failure diagnostics from Savannah.  I don't
know why I run into these diagnostics whereas others evidently do not.

remote: *** 912-#endif
remote: *** 913:
remote: *** 914-
remote: *** error: lines with trailing whitespace found
...
remote: *** error: sysdeps/unix/sysv/linux/statx_cp.c: trailing lines
 2022-01-01 11:40:24 -08:00
Adhemerval Zanella
92ff345137 Remove atomic-machine.h atomic typedefs 
Now that memusage.c uses generic types we can remove them.
 2021-12-28 14:57:57 -03:00
Florian Weimer
cca75bd8b5 i386: Explain why __HAVE_64B_ATOMICS has to be 0 2021-11-02 10:26:23 +01:00
Paul Eggert
2b778ceb40 Update copyright dates with scripts/update-copyrights 
I used these shell commands:

../glibc/scripts/update-copyrights $PWD/../gnulib/build-aux/update-copyright
(cd ../glibc && git commit -am"[this commit message]")

and then ignored the output, which consisted lines saying "FOO: warning:
copyright statement not found" for each of 6694 files FOO.
I then removed trailing white space from benchtests/bench-pthread-locks.c
and iconvdata/tst-iconv-big5-hkscs-to-2ucs4.c, to work around this
diagnostic from Savannah:
remote: *** pre-commit check failed ...
remote: *** error: lines with trailing whitespace found
remote: error: hook declined to update refs/heads/master
 2021-01-02 12:17:34 -08:00
Florian Weimer
0f34d426ac x86: Remove UP macro. Define LOCK_PREFIX unconditionally. 
The UP macro is never defined.  Also define LOCK_PREFIX
unconditionally, to the same string.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
 2020-11-13 15:20:03 +01:00
Joseph Myers
d614a75396 Update copyright dates with scripts/update-copyrights. 2020-01-01 00:14:33 +00:00
Paul Eggert
5a82c74822 Prefer https to http for gnu.org and fsf.org URLs 
Also, change sources.redhat.com to sourceware.org.
This patch was automatically generated by running the following shell
script, which uses GNU sed, and which avoids modifying files imported
from upstream:

sed -ri '
  s,(http|ftp)(://(.*\.)?(gnu|fsf|sourceware)\.org($|[^.]|\.[^a-z])),https\2,g
  s,(http|ftp)(://(.*\.)?)sources\.redhat\.com($|[^.]|\.[^a-z]),https\2sourceware.org\4,g
' \
  $(find $(git ls-files) -prune -type f \
      ! -name '*.po' \
      ! -name 'ChangeLog*' \
      ! -path COPYING ! -path COPYING.LIB \
      ! -path manual/fdl-1.3.texi ! -path manual/lgpl-2.1.texi \
      ! -path manual/texinfo.tex ! -path scripts/config.guess \
      ! -path scripts/config.sub ! -path scripts/install-sh \
      ! -path scripts/mkinstalldirs ! -path scripts/move-if-change \
      ! -path INSTALL ! -path  locale/programs/charmap-kw.h \
      ! -path po/libc.pot ! -path sysdeps/gnu/errlist.c \
      ! '(' -name configure \
            -execdir test -f configure.ac -o -f configure.in ';' ')' \
      ! '(' -name preconfigure \
            -execdir test -f preconfigure.ac ';' ')' \
      -print)

and then by running 'make dist-prepare' to regenerate files built
from the altered files, and then executing the following to cleanup:

  chmod a+x sysdeps/unix/sysv/linux/riscv/configure
  # Omit irrelevant whitespace and comment-only changes,
  # perhaps from a slightly-different Autoconf version.
  git checkout -f \
    sysdeps/csky/configure \
    sysdeps/hppa/configure \
    sysdeps/riscv/configure \
    sysdeps/unix/sysv/linux/csky/configure
  # Omit changes that caused a pre-commit check to fail like this:
  # remote: *** error: sysdeps/powerpc/powerpc64/ppc-mcount.S: trailing lines
  git checkout -f \
    sysdeps/powerpc/powerpc64/ppc-mcount.S \
    sysdeps/unix/sysv/linux/s390/s390-64/syscall.S
  # Omit change that caused a pre-commit check to fail like this:
  # remote: *** error: sysdeps/sparc/sparc64/multiarch/memcpy-ultra3.S: last line does not end in newline
  git checkout -f sysdeps/sparc/sparc64/multiarch/memcpy-ultra3.S
 2019-09-07 02:43:31 -07:00
Joseph Myers
04277e02d7 Update copyright dates with scripts/update-copyrights. 
* All files with FSF copyright notices: Update copyright dates
	using scripts/update-copyrights.
	* locale/programs/charmap-kw.h: Regenerated.
	* locale/programs/locfile-kw.h: Likewise.
 2019-01-01 00:11:28 +00:00
H.J. Lu
cd815050e5 x86: Merge i386/x86_64 atomic-machine.h 
Merge i386 and x86_64 atomic-machine.h to x86 atomic-machine.h.

Tested on i686 and x86_64 as well as with build-many-glibcs.py.

	* sysdeps/i386/atomic-machine.h: Merged with ...
	* sysdeps/x86_64/atomic-machine.h: To ...
	* sysdeps/x86/atomic-machine.h: This.  New file.
 2018-12-18 04:25:26 -08:00