__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.
