diff options
| author | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2018-04-27 07:36:36 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-04-29 11:33:15 +0200 |
| commit | 74a93ae5c328da09951990e1fece3382b544616c (patch) | |
| tree | 97a1e43144f71ada2ca845f54b794adfb2476d68 /arch | |
| parent | 6288e169a25e416c656604be74f436002fa567a0 (diff) | |
s390: do not bypass BPENTER for interrupt system calls
[ Upstream commit d5feec04fe578c8dbd9e2e1439afc2f0af761ed4 ]
The system call path can be interrupted before the switch back to the
standard branch prediction with BPENTER has been done. The critical
section cleanup code skips forward to .Lsysc_do_svc and bypasses the
BPENTER. In this case the kernel and all subsequent code will run with
the limited branch prediction.
Fixes: eacf67eb9b32 ("s390: run user space and KVM guests with modified branch prediction")
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/s390/kernel/entry.S | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S index 1888b1010e20..6473cd81c8f6 100644 --- a/arch/s390/kernel/entry.S +++ b/arch/s390/kernel/entry.S @@ -1375,6 +1375,7 @@ cleanup_critical: stg %r15,__LC_SYSTEM_TIMER 0: # update accounting time stamp mvc __LC_LAST_UPDATE_TIMER(8),__LC_SYNC_ENTER_TIMER + BPENTER __TI_flags(%r12),_TIF_ISOLATE_BP # set up saved register r11 lg %r15,__LC_KERNEL_STACK la %r9,STACK_FRAME_OVERHEAD(%r15) |