linux.git/arch/s390/kernel/vdso64, branch master

s390/time: steer clocksource on STP sync events

2016-10-28T08:09:02+00:00

On STP sync events the TOD clock will jump in time, either forward or backward. The TOD clocksource claims to be continuous but in case of an STP sync with a negative offset it is not. Subtract the offset injected by the STP sync check from the result of the TOD clocksource to make it continuous again. Add code to drift the offset towards zero with a fixed rate, steering 1 second in ~9 hours. Suggested-by: David Hildenbrand Signed-off-by: Martin Schwidefsky

s390: enable UBSAN

2016-09-20T12:26:23+00:00

This enables UBSAN for s390. We have to disable the null sanitizer as s390 code does access memory via a null pointer (the prefix page). Signed-off-by: Christian Borntraeger Acked-by: Andrey Ryabinin Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky

s390: enable kcov support

2016-06-28T07:32:39+00:00

Now that hopefully all inline assemblies have been converted to single basic blocks we can enable kcov on s390. Note that this patch does not disable as many files on s390 like the x86 variant does. Right now I didn't see a reason to do that, however additional files or directories can be excluded at any time. The runtime overhead seems to be quite high. Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky

s390/vdso: optimize getcpu system call

2016-01-11T12:01:24+00:00

Add the CPU number to the per-cpu vdso data page and add the __kernel_getcpu function to the vdso object to retrieve the CPU number in user space. Suggested-by: Heiko Carstens Reviewed-by: Heiko Carstens Signed-off-by: Martin Schwidefsky

s390/vdso: emit a GNU hash

2015-08-07T07:57:39+00:00

As proposed by Andy Lutomirski create the SysV and the GNU hash for the vdso objects. This may make some dynamic loaders a bit faster. Signed-off-by: Martin Schwidefsky

s390/vdso: fix clock_gettime for CLOCK_THREAD_CPUTIME_ID, -2 and -3

2015-02-12T08:37:21+00:00

Git commit 8d8f2e18a6dbd3d09dd918788422e6ac8c878e96 "s390/vdso: ectg gettime support for CLOCK_THREAD_CPUTIME_ID" broke clock_gettime for CLOCK_THREAD_CPUTIME_ID. Git commit c742b31c03f37c5c499178f09f57381aa6c70131 "fast vdso implementation for CLOCK_THREAD_CPUTIME_ID" introduced the ECTG for clock id -2. Correct would have been clock id -3. Fix the whole mess, CLOCK_THREAD_CPUTIME_ID is based on CPUCLOCK_SCHED and can not be speed up by the vdso. A speedup is only available for clock id -3 which is CPUCLOCK_VIRT for the task currently running on the CPU. Signed-off-by: Martin Schwidefsky

s390/vdso: fix stack corruption

2014-10-27T12:27:02+00:00

The kernel provided vdso functions do not get a stack frame from the calling function and therefore may not change the stack contents, unless they allocate space on their own. This problem was exposed with 070b7be633dc "s390/vdso: replace stck with stcke" which writes 16 bytes instead of 8 bytes into the stack frame. These additional 8 bytes however were indeed used by the caller (glibc) to save data and therefore this data was corrupted by the vdso code. Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky

s390/vdso: add vdso support for coarse clocks

2014-09-09T06:53:27+00:00

Add CLOCK_REALTIME_COARSE and CLOCK_MONOTONIC_COARSE optimization to the 64-bit and 31-bit vdso. Signed-off-by: Martin Schwidefsky

s390/vdso: replace stck with stcke

2014-09-09T06:53:27+00:00

If gettimeofday / clock_gettime are called multiple times in a row the STCK instruction will stall until a difference in the result is visible. This unnecessarily slows down the vdso calls, use stcke instead of stck to get rid of the stall. Signed-off-by: Martin Schwidefsky

s390/vdso: remove NULL pointer check from clock_gettime

2014-09-01T07:56:29+00:00

The explicit NULL pointer check on the timespec argument is only required for clock_getres but not for clock_gettime. Signed-off-by: Martin Schwidefsky