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| author | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2017-05-02 13:36:00 +0200 |
|---|---|---|
| committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2017-05-03 09:08:57 +0200 |
| commit | 07a63cbe8bcb6ba72fb989dcab1ec55ec6c36c7e (patch) | |
| tree | e7ef1fae73975159ed7886988db715af73e73d49 /arch/s390/kernel/entry.S | |
| parent | 89c9fea3c8034cdb2fd745f551cde0b507fd6893 (diff) | |
| download | linux-0-day-07a63cbe8bcb6ba72fb989dcab1ec55ec6c36c7e.tar.gz linux-0-day-07a63cbe8bcb6ba72fb989dcab1ec55ec6c36c7e.tar.xz | |
s390/cputime: fix incorrect system time
git commit c5328901aa1db134 "[S390] entry[64].S improvements" removed
the update of the exit_timer lowcore field from the critical section
cleanup of the .Lsysc_restore/.Lsysc_done and .Lio_restore/.Lio_done
blocks. If the PSW is updated by the critical section cleanup to point to
user space again, the interrupt entry code will do a vtime calculation
after the cleanup completed with an exit_timer value which has *not* been
updated. Due to this incorrect system time deltas are calculated.
If an interrupt occured with an old PSW between .Lsysc_restore/.Lsysc_done
or .Lio_restore/.Lio_done update __LC_EXIT_TIMER with the system entry
time of the interrupt.
Cc: stable@vger.kernel.org # 3.3+
Tested-by: Christian Borntraeger <borntraeger@de.ibm.com>
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 | 21 |
1 files changed, 18 insertions, 3 deletions
diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S index a5f5d3bb3dbc5..e408d9cc5b96a 100644 --- a/arch/s390/kernel/entry.S +++ b/arch/s390/kernel/entry.S @@ -312,6 +312,7 @@ ENTRY(system_call) lg %r14,__LC_VDSO_PER_CPU lmg %r0,%r10,__PT_R0(%r11) mvc __LC_RETURN_PSW(16),__PT_PSW(%r11) +.Lsysc_exit_timer: stpt __LC_EXIT_TIMER mvc __VDSO_ECTG_BASE(16,%r14),__LC_EXIT_TIMER lmg %r11,%r15,__PT_R11(%r11) @@ -623,6 +624,7 @@ ENTRY(io_int_handler) lg %r14,__LC_VDSO_PER_CPU lmg %r0,%r10,__PT_R0(%r11) mvc __LC_RETURN_PSW(16),__PT_PSW(%r11) +.Lio_exit_timer: stpt __LC_EXIT_TIMER mvc __VDSO_ECTG_BASE(16,%r14),__LC_EXIT_TIMER lmg %r11,%r15,__PT_R11(%r11) @@ -1174,15 +1176,23 @@ cleanup_critical: br %r14 .Lcleanup_sysc_restore: + # check if stpt has been executed clg %r9,BASED(.Lcleanup_sysc_restore_insn) + jh 0f + mvc __LC_EXIT_TIMER(8),__LC_ASYNC_ENTER_TIMER + cghi %r11,__LC_SAVE_AREA_ASYNC je 0f + mvc __LC_EXIT_TIMER(8),__LC_MCCK_ENTER_TIMER +0: clg %r9,BASED(.Lcleanup_sysc_restore_insn+8) + je 1f lg %r9,24(%r11) # get saved pointer to pt_regs mvc __LC_RETURN_PSW(16),__PT_PSW(%r9) mvc 0(64,%r11),__PT_R8(%r9) lmg %r0,%r7,__PT_R0(%r9) -0: lmg %r8,%r9,__LC_RETURN_PSW +1: lmg %r8,%r9,__LC_RETURN_PSW br %r14 .Lcleanup_sysc_restore_insn: + .quad .Lsysc_exit_timer .quad .Lsysc_done - 4 .Lcleanup_io_tif: @@ -1190,15 +1200,20 @@ cleanup_critical: br %r14 .Lcleanup_io_restore: + # check if stpt has been executed clg %r9,BASED(.Lcleanup_io_restore_insn) - je 0f + jh 0f + mvc __LC_EXIT_TIMER(8),__LC_MCCK_ENTER_TIMER +0: clg %r9,BASED(.Lcleanup_io_restore_insn+8) + je 1f lg %r9,24(%r11) # get saved r11 pointer to pt_regs mvc __LC_RETURN_PSW(16),__PT_PSW(%r9) mvc 0(64,%r11),__PT_R8(%r9) lmg %r0,%r7,__PT_R0(%r9) -0: lmg %r8,%r9,__LC_RETURN_PSW +1: lmg %r8,%r9,__LC_RETURN_PSW br %r14 .Lcleanup_io_restore_insn: + .quad .Lio_exit_timer .quad .Lio_done - 4 .Lcleanup_idle: |