powerpc/powernv: Fix MCE handler to avoid trashing CR0/CR1 registers.

[mirror_ubuntu-zesty-kernel.git] / arch / powerpc / kernel / exceptions-64s.S

diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index 41091fdf9bd88fbe68d9ef15aeb04c1b59b18e77..df6d45eb41150185e7cc17baa82feead23fa27f3 100644 (file)
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -144,29 +144,14 @@ machine_check_pSeries_1:
         * vector
         */
        SET_SCRATCH0(r13)               /* save r13 */
-#ifdef CONFIG_PPC_P7_NAP
-BEGIN_FTR_SECTION
-       /* Running native on arch 2.06 or later, check if we are
-        * waking up from nap. We only handle no state loss and
-        * supervisor state loss. We do -not- handle hypervisor
-        * state loss at this time.
+       /*
+        * Running native on arch 2.06 or later, we may wakeup from winkle
+        * inside machine check. If yes, then last bit of HSPGR0 would be set
+        * to 1. Hence clear it unconditionally.
         */
-       mfspr   r13,SPRN_SRR1
-       rlwinm. r13,r13,47-31,30,31
-       OPT_GET_SPR(r13, SPRN_CFAR, CPU_FTR_CFAR)
-       beq     9f
-
-       mfspr   r13,SPRN_SRR1
-       rlwinm. r13,r13,47-31,30,31
-       /* waking up from powersave (nap) state */
-       cmpwi   cr1,r13,2
-       /* Total loss of HV state is fatal. let's just stay stuck here */
-       OPT_GET_SPR(r13, SPRN_CFAR, CPU_FTR_CFAR)
-       bgt     cr1,.
-9:
-       OPT_SET_SPR(r13, SPRN_CFAR, CPU_FTR_CFAR)
-END_FTR_SECTION_IFSET(CPU_FTR_HVMODE | CPU_FTR_ARCH_206)
-#endif /* CONFIG_PPC_P7_NAP */
+       GET_PACA(r13)
+       clrrdi  r13,r13,1
+       SET_PACA(r13)
        EXCEPTION_PROLOG_0(PACA_EXMC)
 BEGIN_FTR_SECTION
        b       machine_check_powernv_early
@@ -1273,25 +1258,51 @@ machine_check_handle_early:
         * Check if thread was in power saving mode. We come here when any
         * of the following is true:
         * a. thread wasn't in power saving mode
-        * b. thread was in power saving mode with no state loss or
-        *    supervisor state loss
+        * b. thread was in power saving mode with no state loss,
+        *    supervisor state loss or hypervisor state loss.
         *
-        * Go back to nap again if (b) is true.
+        * Go back to nap/sleep/winkle mode again if (b) is true.
         */
        rlwinm. r11,r12,47-31,30,31     /* Was it in power saving mode? */
        beq     4f                      /* No, it wasn;t */
        /* Thread was in power saving mode. Go back to nap again. */
        cmpwi   r11,2
-       bne     3f
-       /* Supervisor state loss */
+       blt     3f
+       /* Supervisor/Hypervisor state loss */
        li      r0,1
        stb     r0,PACA_NAPSTATELOST(r13)
 3:     bl      machine_check_queue_event
        MACHINE_CHECK_HANDLER_WINDUP
        GET_PACA(r13)
        ld      r1,PACAR1(r13)
-       li      r3,PNV_THREAD_NAP
-       b       pnv_enter_arch207_idle_mode
+       /*
+        * Check what idle state this CPU was in and go back to same mode
+        * again.
+        */
+       lbz     r3,PACA_THREAD_IDLE_STATE(r13)
+       cmpwi   r3,PNV_THREAD_NAP
+       bgt     10f
+       IDLE_STATE_ENTER_SEQ(PPC_NAP)
+       /* No return */
+10:
+       cmpwi   r3,PNV_THREAD_SLEEP
+       bgt     2f
+       IDLE_STATE_ENTER_SEQ(PPC_SLEEP)
+       /* No return */
+
+2:
+       /*
+        * Go back to winkle. Please note that this thread was woken up in
+        * machine check from winkle and have not restored the per-subcore
+        * state. Hence before going back to winkle, set last bit of HSPGR0
+        * to 1. This will make sure that if this thread gets woken up
+        * again at reset vector 0x100 then it will get chance to restore
+        * the subcore state.
+        */
+       ori     r13,r13,1
+       SET_PACA(r13)
+       IDLE_STATE_ENTER_SEQ(PPC_WINKLE)
+       /* No return */
 4:
 #endif
        /*