powerpc/64s/exception: untangle early machine check handler branch

machine_check_early_common now branches to machine_check_handle_early
which is its only caller.

Move interleaving code out of the way, and remove the branch.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190802105709.27696-16-npiggin@gmail.com

diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index af18d0f..3a7f180 100644 (file)
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -956,6 +956,16 @@ TRAMP_REAL_BEGIN(machine_check_fwnmi)
 
 TRAMP_KVM_SKIP(PACA_EXMC, 0x200)
 
+#define MACHINE_CHECK_HANDLER_WINDUP                   \
+       /* Clear MSR_RI before setting SRR0 and SRR1. */\
+       li      r9,0;                                   \
+       mtmsrd  r9,1;           /* Clear MSR_RI */      \
+       /* Decrement paca->in_mce now RI is clear. */   \
+       lhz     r12,PACA_IN_MCE(r13);                   \
+       subi    r12,r12,1;                              \
+       sth     r12,PACA_IN_MCE(r13);                   \
+       EXCEPTION_RESTORE_REGS EXC_STD
+
 EXC_COMMON_BEGIN(machine_check_early_common)
        mtctr   r10                     /* Restore ctr */
        mfspr   r11,SPRN_SRR0
@@ -1011,74 +1021,7 @@ BEGIN_FTR_SECTION
 END_FTR_SECTION_IFSET(CPU_FTR_HVMODE)
        li      r10,MSR_RI
        mtmsrd  r10,1
-       b       machine_check_handle_early
 
-EXC_COMMON_BEGIN(machine_check_common)
-       /*
-        * Machine check is different because we use a different
-        * save area: PACA_EXMC instead of PACA_EXGEN.
-        */
-       EXCEPTION_COMMON(PACA_EXMC, 0x200)
-       FINISH_NAP
-       RECONCILE_IRQ_STATE(r10, r11)
-       ld      r3,PACA_EXMC+EX_DAR(r13)
-       lwz     r4,PACA_EXMC+EX_DSISR(r13)
-       /* Enable MSR_RI when finished with PACA_EXMC */
-       li      r10,MSR_RI
-       mtmsrd  r10,1
-       std     r3,_DAR(r1)
-       std     r4,_DSISR(r1)
-       bl      save_nvgprs
-       addi    r3,r1,STACK_FRAME_OVERHEAD
-       bl      machine_check_exception
-       b       ret_from_except
-
-#define MACHINE_CHECK_HANDLER_WINDUP                   \
-       /* Clear MSR_RI before setting SRR0 and SRR1. */\
-       li      r9,0;                                   \
-       mtmsrd  r9,1;           /* Clear MSR_RI */      \
-       /* Decrement paca->in_mce now RI is clear. */   \
-       lhz     r12,PACA_IN_MCE(r13);                   \
-       subi    r12,r12,1;                              \
-       sth     r12,PACA_IN_MCE(r13);                   \
-       EXCEPTION_RESTORE_REGS EXC_STD
-
-#ifdef CONFIG_PPC_P7_NAP
-/*
- * This is an idle wakeup. Low level machine check has already been
- * done. Queue the event then call the idle code to do the wake up.
- */
-EXC_COMMON_BEGIN(machine_check_idle_common)
-       bl      machine_check_queue_event
-
-       /*
-        * We have not used any non-volatile GPRs here, and as a rule
-        * most exception code including machine check does not.
-        * Therefore PACA_NAPSTATELOST does not need to be set. Idle
-        * wakeup will restore volatile registers.
-        *
-        * Load the original SRR1 into r3 for pnv_powersave_wakeup_mce.
-        *
-        * Then decrement MCE nesting after finishing with the stack.
-        */
-       ld      r3,_MSR(r1)
-       ld      r4,_LINK(r1)
-
-       lhz     r11,PACA_IN_MCE(r13)
-       subi    r11,r11,1
-       sth     r11,PACA_IN_MCE(r13)
-
-       mtlr    r4
-       rlwinm  r10,r3,47-31,30,31
-       cmpwi   cr1,r10,2
-       bltlr   cr1     /* no state loss, return to idle caller */
-       b       idle_return_gpr_loss
-#endif
-       /*
-        * Handle machine check early in real mode. We come here with
-        * ME=1, MMU (IR=0 and DR=0) off and using MC emergency stack.
-        */
-EXC_COMMON_BEGIN(machine_check_handle_early)
        bl      save_nvgprs
        addi    r3,r1,STACK_FRAME_OVERHEAD
        bl      machine_check_early
@@ -1157,6 +1100,58 @@ END_FTR_SECTION_IFSET(CPU_FTR_CFAR)
        EXCEPTION_PROLOG_1 EXC_STD, PACA_EXMC, 1, 0x200, 1, 1, 0
        EXCEPTION_PROLOG_2_REAL machine_check_common, EXC_STD, 0
 
+EXC_COMMON_BEGIN(machine_check_common)
+       /*
+        * Machine check is different because we use a different
+        * save area: PACA_EXMC instead of PACA_EXGEN.
+        */
+       EXCEPTION_COMMON(PACA_EXMC, 0x200)
+       FINISH_NAP
+       RECONCILE_IRQ_STATE(r10, r11)
+       ld      r3,PACA_EXMC+EX_DAR(r13)
+       lwz     r4,PACA_EXMC+EX_DSISR(r13)
+       /* Enable MSR_RI when finished with PACA_EXMC */
+       li      r10,MSR_RI
+       mtmsrd  r10,1
+       std     r3,_DAR(r1)
+       std     r4,_DSISR(r1)
+       bl      save_nvgprs
+       addi    r3,r1,STACK_FRAME_OVERHEAD
+       bl      machine_check_exception
+       b       ret_from_except
+
+#ifdef CONFIG_PPC_P7_NAP
+/*
+ * This is an idle wakeup. Low level machine check has already been
+ * done. Queue the event then call the idle code to do the wake up.
+ */
+EXC_COMMON_BEGIN(machine_check_idle_common)
+       bl      machine_check_queue_event
+
+       /*
+        * We have not used any non-volatile GPRs here, and as a rule
+        * most exception code including machine check does not.
+        * Therefore PACA_NAPSTATELOST does not need to be set. Idle
+        * wakeup will restore volatile registers.
+        *
+        * Load the original SRR1 into r3 for pnv_powersave_wakeup_mce.
+        *
+        * Then decrement MCE nesting after finishing with the stack.
+        */
+       ld      r3,_MSR(r1)
+       ld      r4,_LINK(r1)
+
+       lhz     r11,PACA_IN_MCE(r13)
+       subi    r11,r11,1
+       sth     r11,PACA_IN_MCE(r13)
+
+       mtlr    r4
+       rlwinm  r10,r3,47-31,30,31
+       cmpwi   cr1,r10,2
+       bltlr   cr1     /* no state loss, return to idle caller */
+       b       idle_return_gpr_loss
+#endif
+
 EXC_COMMON_BEGIN(unrecoverable_mce)
        /*
         * We are going down. But there are chances that we might get hit by