lkml.org 
[lkml]   [2018]   [Apr]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 4.14 53/80] s390: do not bypass BPENTER for interrupt system calls
    Date
    4.14-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Martin Schwidefsky <schwidefsky@de.ibm.com>


    [ 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>
    ---
    arch/s390/kernel/entry.S | 1 +
    1 file changed, 1 insertion(+)

    --- 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)

    \
     
     \ /
      Last update: 2018-04-27 16:47    [W:4.296 / U:0.020 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site