[SPARC64]: Fix trap state reading for instruction_access_exception.

1) Read ASI_IMMU SFSR not ASI_DMMU.
2) IMMU has no SFAR, read TPC instead
3) Delete old and incorrect comment about the DTLB protection
   trap having a dependency on the SFSR contents in order to
   function correctly

Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/arch/sparc64/kernel/entry.S b/arch/sparc64/kernel/entry.S
index 88332f0..6d0476f 100644 (file)
--- a/arch/sparc64/kernel/entry.S
+++ b/arch/sparc64/kernel/entry.S
@@ -690,11 +690,6 @@ netbsd_syscall:
        retl
         nop
 
-       /* These next few routines must be sure to clear the
-        * SFSR FaultValid bit so that the fast tlb data protection
-        * handler does not flush the wrong context and lock up the
-        * box.
-        */
        .globl          __do_data_access_exception
        .globl          __do_data_access_exception_tl1
 __do_data_access_exception_tl1:
@@ -733,9 +728,8 @@ __do_instruction_access_exception_tl1:
        rdpr            %pstate, %g4
        wrpr            %g4, PSTATE_MG|PSTATE_AG, %pstate
        mov             TLB_SFSR, %g3
-       mov             DMMU_SFAR, %g5
-       ldxa            [%g3] ASI_DMMU, %g4     ! Get SFSR
-       ldxa            [%g5] ASI_DMMU, %g5     ! Get SFAR
+       ldxa            [%g3] ASI_IMMU, %g4     ! Get SFSR
+       rdpr            %tpc, %g5               ! IMMU has no SFAR, use TPC
        stxa            %g0, [%g3] ASI_IMMU     ! Clear FaultValid bit
        membar          #Sync
        sethi           %hi(109f), %g7
@@ -752,9 +746,8 @@ __do_instruction_access_exception:
        rdpr            %pstate, %g4
        wrpr            %g4, PSTATE_MG|PSTATE_AG, %pstate
        mov             TLB_SFSR, %g3
-       mov             DMMU_SFAR, %g5
-       ldxa            [%g3] ASI_DMMU, %g4     ! Get SFSR
-       ldxa            [%g5] ASI_DMMU, %g5     ! Get SFAR
+       ldxa            [%g3] ASI_IMMU, %g4     ! Get SFSR
+       rdpr            %tpc, %g5               ! IMMU has no SFAR, use TPC
        stxa            %g0, [%g3] ASI_IMMU     ! Clear FaultValid bit
        membar          #Sync
        sethi           %hi(109f), %g7