BMC/Intel-BMC/linux.git/arch/s390/kernel/vdso64/clock_gettime.S, branch dev

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

s390/time,vdso: fix clock_gettime for CLOCK_MONOTONIC

2013-12-02T17:15:25+00:00

With git commit 79c74ecbebf76732f91b82a62ce7fc8a88326962 "s390/time,vdso: convert to the new update_vsyscall interface" the new update_vsyscall function already does the sum of xtime and wall_to_monotonic. The old update_vsyscall function only copied the wall_to_monotonic offset. The vdso code needs to be modified to take this into consideration. Signed-off-by: Martin Schwidefsky

s390/vdso: ectg gettime support for CLOCK_THREAD_CPUTIME_ID

2013-12-02T14:31:10+00:00

The code to use the ECTG instruction to calculate the cputime for the current thread is currently used only for the per-thread CPU-clock with the clockid -2 (PID=0, VIRT=1). Use the same code for the clockid CLOCK_THREAD_CPUTIME_ID to speed up the more common clockid as well. Reported-by: Heiko Carstens Signed-off-by: Martin Schwidefsky

s390/time,vdso: convert to the new update_vsyscall interface

2013-11-25T08:15:39+00:00

Switch to the improved update_vsyscall interface that provides sub-nanosecond precision for gettimeofday and clock_gettime. Signed-off-by: Martin Schwidefsky

[S390] vdso: get rid of redefinition warnings

2010-10-29T14:50:50+00:00

The CLOCK_* defines in asm-offsets.c are only used for the vdso code however in the meantime they cause other trouble. Just rename them to get permanently rid of this: In file included from /home2/heicarst/linux-2.6/arch/s390/include/asm/asm-offsets.h:1:0, from arch/s390/mm/fault.c:33: include/generated/asm-offsets.h:53:0: warning: "CLOCK_REALTIME" redefined include/linux/time.h:286:0: note: this is the location of the previous definition include/generated/asm-offsets.h:54:0: warning: "CLOCK_MONOTONIC" redefined include/linux/time.h:287:0: note: this is the location of the previous definition Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky

[S390] vdso: use ntp adjusted clock multiplier

2010-04-22T15:17:19+00:00

Commit "timekeeping: Fix clock_gettime vsyscall time warp" (0696b711e) introduced the new parameter "mult" to update_vsyscall(). This parameter contains the internal NTP adjusted clock multiplier. The s390x vdso did not use this adjusted multiplier. Instead, it used the constant clock multiplier for gettimeofday() and clock_gettime() variants. This may result in observable time warps as explained in commit 0696b711e. Make the NTP adjusted clock multiplier available to the s390x vdso implementation and use it for time calculations. Cc: Signed-off-by: Hendrik Brueckner Signed-off-by: Martin Schwidefsky