diff mbox

[1/4] powerpc: Fix static-linked version of __ppc_get_timebase_freq [BZ #24640]

Message ID 20190613151145.22243-2-raoni@linux.ibm.com
State Superseded
Delegated to: Adhemerval Zanella Netto
Headers

Commit Message

Raoni Fassina Firmino June 13, 2019, 3:11 p.m. UTC 
  From: Stan Shebs <stanshebs@google.com>

__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.

ChangeLog:

2019-06-13  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/get_timebase_freq.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Adhemerval Zanella June 14, 2019, 3:18 p.m. UTC | #1 
On 13/06/2019 12:11, Raoni Fassina Firmino wrote:
> From: Stan Shebs <stanshebs@google.com>
> 
> __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.
> 
> ChangeLog:
> 
> 2019-06-13  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.

Please include the testcase [1] on this patch.  LGTM with this change.

Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>

[1] https://sourceware.org/ml/libc-alpha/2019-06/msg00285.html

> ---
>  sysdeps/unix/sysv/linux/powerpc/get_timebase_freq.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> 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 mbox

Patch

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