powerpc: Fix static-linked version of __ppc_get_timebase_freq [BZ #24640]

__ppc_get_timebase_freq() always return 0 when using static linked
glibc.

This is a minimal example.c to reproduce:

    /******************************/
    #include <inttypes.h>
    #include <stdint.h>
    #include <stdio.h>
    #include <sys/platform/ppc.h>

    int main() {
        uint64_t freq = __ppc_get_timebase_freq();
        printf("Time Base frequency = %"PRIu64" Hz\n", freq);
        if (freq == 0)
            return -1;
        return 0;
    }
    /******************************/

Compile command: gcc -static example.c

This bug has been reproduced, fixed and tested on all powerpc platforms
(ppc32, ppc64 and ppc64le).

The underlying code of __ppc_get_timebase_freq uses __get_timebase_freq
that has a different implementation for shared and static version of
glibc.  In the static version, there is an incorrect sense in the if
check for the fd returned when opening /proc/cpuinfo.

This solution is mostly a cherry-pick from:

  commit 4791e4f773d060c1a37b27aac5b03cdfa9327afc
  Author: Stan Shebs <stanshebs@google.com>
  Date:   Fri May 17 12:25:19 2019 -0700
  Subject: Fix sense of a test in the static-linking version of ppc get_clockfreq

That is in branch glibc/google/grte/v5-2.27/master and was mentioned for
inclusion on master here:

  https://www.sourceware.org/ml/libc-alpha/2019-05/msg00409.html

Adapted from original fix for get_clockfreq. That code was moved to
get_timebase_freq.

Also added a static-build testcase for __ppc_get_timebase_freq since the
underlying function has different implementations for shared and static
build.

	[BZ #24640]
	* sysdeps/unix/sysv/linux/powerpc/get_timebase_freq.c
	[!SHARED] (__get_timebase_freq): Fix sense of a test in the
	static-linking version.
	* sysdeps/unix/sysv/linux/powerpc/Makefile
	(tests-static): Add test-gettimebasefreq-static.
	(tests): Likewise.
	* sysdeps/unix/sysv/linux/powerpc/test-gettimebasefreq-static.c:
	New file.

3 files changed, 22 insertions, 1 deletions

diff --git a/sysdeps/unix/sysv/linux/powerpc/Makefile b/sysdeps/unix/sysv/linux/powerpc/Makefile
index 19ac59d862..1596238afa 100644
--- a/sysdeps/unix/sysv/linux/powerpc/Makefile
+++ b/sysdeps/unix/sysv/linux/powerpc/Makefile
@@ -25,6 +25,8 @@ endif
 ifeq ($(subdir),misc)
 sysdep_headers += bits/ppc.h
 sysdep_routines += get_timebase_freq
+tests-static += test-gettimebasefreq-static
+tests += $(tests-static)
 tests += test-gettimebasefreq
 tests += test-powerpc-linux-sysconf
 endif
diff --git a/sysdeps/unix/sysv/linux/powerpc/get_timebase_freq.c b/sysdeps/unix/sysv/linux/powerpc/get_timebase_freq.c
index 23e7694d87..c245e97526 100644
--- a/sysdeps/unix/sysv/linux/powerpc/get_timebase_freq.c
+++ b/sysdeps/unix/sysv/linux/powerpc/get_timebase_freq.c
@@ -39,7 +39,7 @@ __get_timebase_freq (void)
      timebase        : 33333333
      We search for this line and convert the number into an integer.  */
   int fd = __open_nocancel ("/proc/cpuinfo", O_RDONLY);
-  if (__glibc_likely (fd != -1))
+  if (__glibc_unlikely (fd == -1))
     return result;
 
   /* The timebase will be in the 1st 1024 bytes for systems with up
diff --git a/sysdeps/unix/sysv/linux/powerpc/test-gettimebasefreq-static.c b/sysdeps/unix/sysv/linux/powerpc/test-gettimebasefreq-static.c
new file mode 100644
index 0000000000..58b4eee98d
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/powerpc/test-gettimebasefreq-static.c
@@ -0,0 +1,19 @@
+/* Check __ppc_get_timebase_freq() for architecture changes
+   Copyright (C) 2019 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include "test-gettimebasefreq.c"