powernv/pseries: consolidate code for mce early handling.

Now that other platforms also implements real mode mce handler,
lets consolidate the code by sharing existing powernv machine check
early code. Rename machine_check_powernv_early to
machine_check_common_early and reuse the code.

Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index b36e11d..301a6a8 100644 (file)
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -244,14 +244,13 @@ EXC_REAL_BEGIN(machine_check, 0x200, 0x100)
        SET_SCRATCH0(r13)               /* save r13 */
        EXCEPTION_PROLOG_0(PACA_EXMC)
 BEGIN_FTR_SECTION
-       b       machine_check_powernv_early
+       b       machine_check_common_early
 FTR_SECTION_ELSE
        b       machine_check_pSeries_0
 ALT_FTR_SECTION_END_IFSET(CPU_FTR_HVMODE)
 EXC_REAL_END(machine_check, 0x200, 0x100)
 EXC_VIRT_NONE(0x4200, 0x100)
-TRAMP_REAL_BEGIN(machine_check_powernv_early)
-BEGIN_FTR_SECTION
+TRAMP_REAL_BEGIN(machine_check_common_early)
        EXCEPTION_PROLOG_1(PACA_EXMC, NOTEST, 0x200)
        /*
         * Register contents:
@@ -305,7 +304,9 @@ BEGIN_FTR_SECTION
        /* Save r9 through r13 from EXMC save area to stack frame. */
        EXCEPTION_PROLOG_COMMON_2(PACA_EXMC)
        mfmsr   r11                     /* get MSR value */
+BEGIN_FTR_SECTION
        ori     r11,r11,MSR_ME          /* turn on ME bit */
+END_FTR_SECTION_IFSET(CPU_FTR_HVMODE)
        ori     r11,r11,MSR_RI          /* turn on RI bit */
        LOAD_HANDLER(r12, machine_check_handle_early)
 1:     mtspr   SPRN_SRR0,r12
@@ -324,7 +325,6 @@ BEGIN_FTR_SECTION
        andc    r11,r11,r10             /* Turn off MSR_ME */
        b       1b
        b       .       /* prevent speculative execution */
-END_FTR_SECTION_IFSET(CPU_FTR_HVMODE)
 
 TRAMP_REAL_BEGIN(machine_check_pSeries)
        .globl machine_check_fwnmi
@@ -332,7 +332,7 @@ machine_check_fwnmi:
        SET_SCRATCH0(r13)               /* save r13 */
        EXCEPTION_PROLOG_0(PACA_EXMC)
 BEGIN_FTR_SECTION
-       b       machine_check_pSeries_early
+       b       machine_check_common_early
 END_FTR_SECTION_IFCLR(CPU_FTR_HVMODE)
 machine_check_pSeries_0:
        EXCEPTION_PROLOG_1(PACA_EXMC, KVMTEST_PR, 0x200)
@@ -345,103 +345,6 @@ machine_check_pSeries_0:
 
 TRAMP_KVM_SKIP(PACA_EXMC, 0x200)
 
-TRAMP_REAL_BEGIN(machine_check_pSeries_early)
-BEGIN_FTR_SECTION
-       EXCEPTION_PROLOG_1(PACA_EXMC, NOTEST, 0x200)
-       mr      r10,r1                  /* Save r1 */
-       lhz     r11,PACA_IN_MCE(r13)
-       cmpwi   r11,0                   /* Are we in nested machine check */
-       bne     0f                      /* Yes, we are. */
-       /* First machine check entry */
-       ld      r1,PACAMCEMERGSP(r13)   /* Use MC emergency stack */
-0:     subi    r1,r1,INT_FRAME_SIZE    /* alloc stack frame */
-       addi    r11,r11,1               /* increment paca->in_mce */
-       sth     r11,PACA_IN_MCE(r13)
-       /* Limit nested MCE to level 4 to avoid stack overflow */
-       cmpwi   r11,MAX_MCE_DEPTH
-       bgt     1f                      /* Check if we hit limit of 4 */
-       mfspr   r11,SPRN_SRR0           /* Save SRR0 */
-       mfspr   r12,SPRN_SRR1           /* Save SRR1 */
-       EXCEPTION_PROLOG_COMMON_1()
-       EXCEPTION_PROLOG_COMMON_2(PACA_EXMC)
-       EXCEPTION_PROLOG_COMMON_3(0x200)
-       addi    r3,r1,STACK_FRAME_OVERHEAD
-       BRANCH_LINK_TO_FAR(machine_check_early) /* Function call ABI */
-       ld      r12,_MSR(r1)
-       andi.   r11,r12,MSR_PR          /* See if coming from user. */
-       bne     2f                      /* continue in V mode if we are. */
-
-       /*
-        * At this point we are not sure about what context we come from.
-        * We may be in the middle of switching stack. r1 may not be valid.
-        * Hence stay on emergency stack, call machine_check_exception and
-        * return from the interrupt.
-        * But before that, check if this is an un-recoverable exception.
-        * If yes, then stay on emergency stack and panic.
-        */
-       andi.   r11,r12,MSR_RI
-       beq     1f
-
-       /*
-        * Check if we have successfully handled/recovered from error, if not
-        * then stay on emergency stack and panic.
-        */
-       cmpdi   r3,0            /* see if we handled MCE successfully */
-       beq     1f              /* if !handled then panic */
-
-       /* Stay on emergency stack and return from interrupt. */
-       LOAD_HANDLER(r10,mce_return)
-       mtspr   SPRN_SRR0,r10
-       ld      r10,PACAKMSR(r13)
-       mtspr   SPRN_SRR1,r10
-       RFI_TO_KERNEL
-       b       .
-
-1:     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, hypervisor will
-        * power cycle the lpar, instead of getting into MCE loop.
-        */
-       li      r3,MSR_ME
-       andc    r10,r10,r3              /* Turn off MSR_ME */
-       mtspr   SPRN_SRR1,r10
-       RFI_TO_KERNEL
-       b       .
-
-       /* Move original SRR0 and SRR1 into the respective regs */
-2:     ld      r9,_MSR(r1)
-       mtspr   SPRN_SRR1,r9
-       ld      r3,_NIP(r1)
-       mtspr   SPRN_SRR0,r3
-       ld      r9,_CTR(r1)
-       mtctr   r9
-       ld      r9,_XER(r1)
-       mtxer   r9
-       ld      r9,_LINK(r1)
-       mtlr    r9
-       REST_GPR(0, r1)
-       REST_8GPRS(2, r1)
-       REST_GPR(10, r1)
-       ld      r11,_CCR(r1)
-       mtcr    r11
-       /* Decrement paca->in_mce. */
-       lhz     r12,PACA_IN_MCE(r13)
-       subi    r12,r12,1
-       sth     r12,PACA_IN_MCE(r13)
-       REST_GPR(11, r1)
-       REST_2GPRS(12, r1)
-       /* restore original r1. */
-       ld      r1,GPR1(r1)
-       SET_SCRATCH0(r13)               /* save r13 */
-       EXCEPTION_PROLOG_0(PACA_EXMC)
-       b       machine_check_pSeries_0
-END_FTR_SECTION_IFCLR(CPU_FTR_HVMODE)
-
 EXC_COMMON_BEGIN(machine_check_common)
        /*
         * Machine check is different because we use a different
@@ -540,6 +443,9 @@ EXC_COMMON_BEGIN(machine_check_handle_early)
        bl      machine_check_early
        std     r3,RESULT(r1)   /* Save result */
        ld      r12,_MSR(r1)
+BEGIN_FTR_SECTION
+       b       4f
+END_FTR_SECTION_IFCLR(CPU_FTR_HVMODE)
 
 #ifdef CONFIG_PPC_P7_NAP
        /*
@@ -563,11 +469,12 @@ EXC_COMMON_BEGIN(machine_check_handle_early)
         */
        rldicl. r11,r12,4,63            /* See if MC hit while in HV mode. */
        beq     5f
-       andi.   r11,r12,MSR_PR          /* See if coming from user. */
+4:     andi.   r11,r12,MSR_PR          /* See if coming from user. */
        bne     9f                      /* continue in V mode if we are. */
 
 5:
 #ifdef CONFIG_KVM_BOOK3S_64_HANDLER
+BEGIN_FTR_SECTION
        /*
         * We are coming from kernel context. Check if we are coming from
         * guest. if yes, then we can continue. We will fall through
@@ -576,6 +483,7 @@ EXC_COMMON_BEGIN(machine_check_handle_early)
        lbz     r11,HSTATE_IN_GUEST(r13)
        cmpwi   r11,0                   /* Check if coming from guest */
        bne     9f                      /* continue if we are. */
+END_FTR_SECTION_IFSET(CPU_FTR_HVMODE)
 #endif
        /*
         * At this point we are not sure about what context we come from.
@@ -610,6 +518,7 @@ EXC_COMMON_BEGIN(machine_check_handle_early)
        cmpdi   r3,0            /* see if we handled MCE successfully */
 
        beq     1b              /* if !handled then panic */
+BEGIN_FTR_SECTION
        /*
         * Return from MC interrupt.
         * Queue up the MCE event so that we can log it later, while
@@ -618,10 +527,24 @@ EXC_COMMON_BEGIN(machine_check_handle_early)
        bl      machine_check_queue_event
        MACHINE_CHECK_HANDLER_WINDUP
        RFI_TO_USER_OR_KERNEL
+FTR_SECTION_ELSE
+       /*
+        * pSeries: Return from MC interrupt. Before that stay on emergency
+        * stack and call machine_check_exception to log the MCE event.
+        */
+       LOAD_HANDLER(r10,mce_return)
+       mtspr   SPRN_SRR0,r10
+       ld      r10,PACAKMSR(r13)
+       mtspr   SPRN_SRR1,r10
+       RFI_TO_KERNEL
+       b       .
+ALT_FTR_SECTION_END_IFSET(CPU_FTR_HVMODE)
 9:
        /* Deliver the machine check to host kernel in V mode. */
        MACHINE_CHECK_HANDLER_WINDUP
-       b       machine_check_pSeries
+       SET_SCRATCH0(r13)               /* save r13 */
+       EXCEPTION_PROLOG_0(PACA_EXMC)
+       b       machine_check_pSeries_0
 
 EXC_COMMON_BEGIN(unrecover_mce)
        /* Invoke machine_check_exception to print MCE event and panic. */
@@ -639,29 +562,7 @@ EXC_COMMON_BEGIN(mce_return)
        /* Invoke machine_check_exception to print MCE event and return. */
        addi    r3,r1,STACK_FRAME_OVERHEAD
        bl      machine_check_exception
-       ld      r9,_MSR(r1)
-       mtspr   SPRN_SRR1,r9
-       ld      r3,_NIP(r1)
-       mtspr   SPRN_SRR0,r3
-       ld      r9,_CTR(r1)
-       mtctr   r9
-       ld      r9,_XER(r1)
-       mtxer   r9
-       ld      r9,_LINK(r1)
-       mtlr    r9
-       REST_GPR(0, r1)
-       REST_8GPRS(2, r1)
-       REST_GPR(10, r1)
-       ld      r11,_CCR(r1)
-       mtcr    r11
-       /* Decrement paca->in_mce. */
-       lhz     r12,PACA_IN_MCE(r13)
-       subi    r12,r12,1
-       sth     r12,PACA_IN_MCE(r13)
-       REST_GPR(11, r1)
-       REST_2GPRS(12, r1)
-       /* restore original r1. */
-       ld      r1,GPR1(r1)
+       MACHINE_CHECK_HANDLER_WINDUP
        RFI_TO_KERNEL
        b       .