[v2] powerpc: Fix static-linked version of __ppc_get_timebase_freq [BZ #24640]

  From: Stan Shebs <stanshebs@google.com>

Originally part of a larger pathset[1].

Changes since v1:

  - Merged fix & testcase in one patch.
    Originally patches #1 and #2[2,3].

[1] https://www.sourceware.org/ml/libc-alpha/2019-06/msg00283.html
[2] https://www.sourceware.org/ml/libc-alpha/2019-06/msg00284.html
[3] https://www.sourceware.org/ml/libc-alpha/2019-06/msg00285.html

---- 8< ----

__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.

ChangeLog:

2019-06-19  Stan Shebs  <stanshebs@google.com>
	    Raoni Fassina Firmino  <raoni@linux.ibm.com>

	[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.
---
 sysdeps/unix/sysv/linux/powerpc/Makefile      |  2 ++
 .../sysv/linux/powerpc/get_timebase_freq.c    |  2 +-
 .../powerpc/test-gettimebasefreq-static.c     | 19 +++++++++++++++++++
 3 files changed, 22 insertions(+), 1 deletion(-)
 create mode 100644 sysdeps/unix/sysv/linux/powerpc/test-gettimebasefreq-static.c
  

On 19/06/2019 15:09, Raoni Fassina Firmino wrote:
> From: Stan Shebs <stanshebs@google.com>
> 
> Originally part of a larger pathset[1].
> 
> Changes since v1:
> 
>   - Merged fix & testcase in one patch.
>     Originally patches #1 and #2[2,3].
> 
> [1] https://www.sourceware.org/ml/libc-alpha/2019-06/msg00283.html
> [2] https://www.sourceware.org/ml/libc-alpha/2019-06/msg00284.html
> [3] https://www.sourceware.org/ml/libc-alpha/2019-06/msg00285.html
> 
> ---- 8< ----
> 
> __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.
> 
> ChangeLog:
> 
> 2019-06-19  Stan Shebs  <stanshebs@google.com>
> 	    Raoni Fassina Firmino  <raoni@linux.ibm.com>
> 
> 	[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.

LGTM with the following change.

> ---
>  sysdeps/unix/sysv/linux/powerpc/Makefile      |  2 ++
>  .../sysv/linux/powerpc/get_timebase_freq.c    |  2 +-
>  .../powerpc/test-gettimebasefreq-static.c     | 19 +++++++++++++++++++
>  3 files changed, 22 insertions(+), 1 deletion(-)
>  create mode 100644 sysdeps/unix/sysv/linux/powerpc/test-gettimebasefreq-static.c
> 
> diff --git a/sysdeps/unix/sysv/linux/powerpc/Makefile b/sysdeps/unix/sysv/linux/powerpc/Makefile
> index 19ac59d862..4b7198dcec 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 += test-gettimebasefreq-static

Use $(tests-static) instead.

>  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"
>