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| author | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2017-04-03 13:30:23 +0200 |
|---|---|---|
| committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2017-04-05 07:35:14 +0200 |
| commit | cab36c262ef9a5ddf3c7ae0f8031b191338b3142 (patch) | |
| tree | 35160f929d3067f977ec2f7bc700a019792b23d5 /arch/s390/kernel/entry.S | |
| parent | 6fb81d69d0bb455e6dbb5bd99529e2dea74b93e7 (diff) | |
| download | linux-0-day-cab36c262ef9a5ddf3c7ae0f8031b191338b3142.tar.gz linux-0-day-cab36c262ef9a5ddf3c7ae0f8031b191338b3142.tar.xz | |
s390: use 64-bit lctlg to load task pid to cr4 on context switch
The 32-bit lctl instruction is quite a bit slower than the 64-bit
counter part lctlg. Use the faster instruction.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/kernel/entry.S')
| -rw-r--r-- | arch/s390/kernel/entry.S | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S index fa8b8f28e08b5..02f11018e2df1 100644 --- a/arch/s390/kernel/entry.S +++ b/arch/s390/kernel/entry.S @@ -190,7 +190,9 @@ ENTRY(__switch_to) stg %r15,__LC_KERNEL_STACK # store end of kernel stack lg %r15,__THREAD_ksp(%r1) # load kernel stack of next /* c4 is used in guest detection: arch/s390/kernel/perf_cpum_sf.c */ - lctl %c4,%c4,__TASK_pid(%r3) # load pid to control reg. 4 + xc __SF_EMPTY(8,%r15),__SF_EMPTY(%r15) + mvc __SF_EMPTY+4(4,%r15),__TASK_pid(%r3) + lctlg %c4,%c4,__SF_EMPTY(%r15) # load pid to control reg. 4 mvc __LC_CURRENT_PID(4,%r0),__TASK_pid(%r3) # store pid of next lmg %r6,%r15,__SF_GPRS(%r15) # load gprs of next task TSTMSK __LC_MACHINE_FLAGS,MACHINE_FLAG_LPP |