Public bug reported:
[Impact]
Userspace reads of CNTVCT_EL0 are broken on HiSilicon D05 systems, which breaks
some applications such as OpenMPI.
[Test Case]
#include <sys/times.h>
#include <stdio.h>
int main(int argc, char *argv[])
{
unsigned int freq;
__asm__ __volatile__ ("mrs %0, CNTFRQ_EL0" : "=r" (freq));
printf("freq %d\n",freq);
return (int)freq;
}
==================================
gcc test.c test
./test
This will report an illegal instruction, but should print a frequency
value.
[Regression Risk]
The best way we can minimize risk is to verify on both a system that has an
errata handler for the timer (D05) and a system that doesn't. We should then be
exercising both code paths.
** Affects: linux (Ubuntu)
Importance: High
Assignee: dann frazier (dannf)
Status: In Progress
** Affects: linux (Ubuntu Zesty)
Importance: High
Assignee: dann frazier (dannf)
Status: In Progress
** Also affects: linux (Ubuntu Zesty)
Importance: Undecided
Status: New
** Changed in: linux (Ubuntu)
Assignee: (unassigned) => dann frazier (dannf)
** Changed in: linux (Ubuntu Zesty)
Assignee: (unassigned) => dann frazier (dannf)
** Changed in: linux (Ubuntu)
Importance: Undecided => High
** Changed in: linux (Ubuntu Zesty)
Importance: Undecided => High
** Changed in: linux (Ubuntu)
Status: New => In Progress
** Changed in: linux (Ubuntu Zesty)
Status: New => In Progress
--
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https://bugs.launchpad.net/bugs/1688164
Title:
arm64: Add CNTFRQ_EL0 handler
Status in linux package in Ubuntu:
In Progress
Status in linux source package in Zesty:
In Progress
Bug description:
[Impact]
Userspace reads of CNTVCT_EL0 are broken on HiSilicon D05 systems, which
breaks some applications such as OpenMPI.
[Test Case]
#include <sys/times.h>
#include <stdio.h>
int main(int argc, char *argv[])
{
unsigned int freq;
__asm__ __volatile__ ("mrs %0, CNTFRQ_EL0" : "=r" (freq));
printf("freq %d\n",freq);
return (int)freq;
}
==================================
gcc test.c test
./test
This will report an illegal instruction, but should print a frequency
value.
[Regression Risk]
The best way we can minimize risk is to verify on both a system that has an
errata handler for the timer (D05) and a system that doesn't. We should then be
exercising both code paths.
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1688164/+subscriptions
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