From: Sven Schnelle svens@linux.ibm.com
commit e259b3fafa7de362b04ecd86e7fa9a9e9273e5fb upstream.
During removal of the critical section cleanup the calculation of mt_cycles during idle was removed. This causes invalid accounting on systems with SMT enabled.
Fixes: 0b0ed657fe00 ("s390: remove critical section cleanup from entry.S") Cc: stable@vger.kernel.org # 5.8 Reviewed-by: Heiko Carstens hca@linux.ibm.com Signed-off-by: Sven Schnelle svens@linux.ibm.com Signed-off-by: Heiko Carstens hca@linux.ibm.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/s390/kernel/entry.S | 34 +++++++++++++++++++++++++--------- 1 file changed, 25 insertions(+), 9 deletions(-)
--- a/arch/s390/kernel/entry.S +++ b/arch/s390/kernel/entry.S @@ -112,7 +112,7 @@ _LPP_OFFSET = __LC_LPP
.macro SWITCH_ASYNC savearea,timer tmhh %r8,0x0001 # interrupting from user ? - jnz 2f + jnz 4f #if IS_ENABLED(CONFIG_KVM) lgr %r14,%r9 larl %r13,.Lsie_gmap @@ -125,9 +125,25 @@ _LPP_OFFSET = __LC_LPP #endif 0: larl %r13,.Lpsw_idle_exit cgr %r13,%r9 - jne 1f + jne 3f
- mvc __CLOCK_IDLE_EXIT(8,%r2), __LC_INT_CLOCK + larl %r1,smp_cpu_mtid + llgf %r1,0(%r1) + ltgr %r1,%r1 + jz 2f # no SMT, skip mt_cycles calculation + .insn rsy,0xeb0000000017,%r1,5,__SF_EMPTY+80(%r15) + larl %r3,mt_cycles + ag %r3,__LC_PERCPU_OFFSET + la %r4,__SF_EMPTY+16(%r15) +1: lg %r0,0(%r3) + slg %r0,0(%r4) + alg %r0,64(%r4) + stg %r0,0(%r3) + la %r3,8(%r3) + la %r4,8(%r4) + brct %r1,1b + +2: mvc __CLOCK_IDLE_EXIT(8,%r2), __LC_INT_CLOCK mvc __TIMER_IDLE_EXIT(8,%r2), __LC_ASYNC_ENTER_TIMER # account system time going idle ni __LC_CPU_FLAGS+7,255-_CIF_ENABLED_WAIT @@ -146,17 +162,17 @@ _LPP_OFFSET = __LC_LPP mvc __LC_LAST_UPDATE_TIMER(8),__TIMER_IDLE_EXIT(%r2)
nihh %r8,0xfcfd # clear wait state and irq bits -1: lg %r14,__LC_ASYNC_STACK # are we already on the target stack? +3: lg %r14,__LC_ASYNC_STACK # are we already on the target stack? slgr %r14,%r15 srag %r14,%r14,STACK_SHIFT - jnz 3f + jnz 5f CHECK_STACK \savearea aghi %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE) - j 4f -2: UPDATE_VTIME %r14,%r15,\timer + j 6f +4: UPDATE_VTIME %r14,%r15,\timer BPENTER __TI_flags(%r12),_TIF_ISOLATE_BP -3: lg %r15,__LC_ASYNC_STACK # load async stack -4: la %r11,STACK_FRAME_OVERHEAD(%r15) +5: lg %r15,__LC_ASYNC_STACK # load async stack +6: la %r11,STACK_FRAME_OVERHEAD(%r15) .endm
.macro UPDATE_VTIME w1,w2,enter_timer