1 files changed, 37 insertions, 3 deletions

diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index 20f11eb4dff7..274a86d001c7 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -1389,6 +1389,7 @@ machine_check_handle_early:
         bl      save_nvgprs
         addi    r3,r1,STACK_FRAME_OVERHEAD
         bl      machine_check_early
+        std     r3,RESULT(r1)   /* Save result */
         ld      r12,_MSR(r1)
 #ifdef  CONFIG_PPC_P7_NAP
         /*
@@ -1443,11 +1444,33 @@ machine_check_handle_early:
          */
         andi.   r11,r12,MSR_RI
         bne     2f
-1:      addi    r3,r1,STACK_FRAME_OVERHEAD
-        bl      unrecoverable_exception
-        b       1b
+1:      mfspr   r11,SPRN_SRR0
+        ld      r10,PACAKBASE(r13)
+        LOAD_HANDLER(r10,unrecover_mce)
+        mtspr   SPRN_SRR0,r10
+        ld      r10,PACAKMSR(r13)
+        /*
+         * We are going down. But there are chances that we might get hit by
+         * another MCE during panic path and we may run into unstable state
+         * with no way out. Hence, turn ME bit off while going down, so that
+         * when another MCE is hit during panic path, system will checkstop
+         * and hypervisor will get restarted cleanly by SP.
+         */
+        li      r3,MSR_ME
+        andc    r10,r10,r3              /* Turn off MSR_ME */
+        mtspr   SPRN_SRR1,r10
+        rfid
+        b       .
 2:
         /*
+         * Check if we have successfully handled/recovered from error, if not
+         * then stay on emergency stack and panic.
+         */
+        ld      r3,RESULT(r1)   /* Load result */
+        cmpdi   r3,0            /* see if we handled MCE successfully */
+
+        beq     1b              /* if !handled then panic */
+        /*
          * Return from MC interrupt.
          * Queue up the MCE event so that we can log it later, while
          * returning from kernel or opal call.
@@ -1460,6 +1483,17 @@ machine_check_handle_early:
         MACHINE_CHECK_HANDLER_WINDUP
         b       machine_check_pSeries
 
+unrecover_mce:
+        /* Invoke machine_check_exception to print MCE event and panic. */
+        addi    r3,r1,STACK_FRAME_OVERHEAD
+        bl      .machine_check_exception
+        /*
+         * We will not reach here. Even if we did, there is no way out. Call
+         * unrecoverable_exception and die.
+         */
+1:      addi    r3,r1,STACK_FRAME_OVERHEAD
+        bl      .unrecoverable_exception
+        b       1b
 /*
  * r13 points to the PACA, r9 contains the saved CR,
  * r12 contain the saved SRR1, SRR0 is still ready for return