parisc: Simplify fast path for non-access data TLB faults

With the latest cache fix for non-access faults and the support for
non-access faults (code 17) in handle_interruption, we can remove
the fast path emulation for fdc, fic, pdc, lpa, probe and probei
instructions.

Signed-off-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>

diff --git a/arch/parisc/kernel/entry.S b/arch/parisc/kernel/entry.S
index 6e9cdb2..ecf5015 100644 (file)
--- a/arch/parisc/kernel/entry.S
+++ b/arch/parisc/kernel/entry.S
@@ -1288,74 +1288,12 @@ nadtlb_check_alias_20:
 nadtlb_emulate:
 
        /*
-        * Non access misses can be caused by fdc,fic,pdc,lpa,probe and
-        * probei instructions. We don't want to fault for these
-        * instructions (not only does it not make sense, it can cause
-        * deadlocks, since some flushes are done with the mmap
-        * semaphore held). If the translation doesn't exist, we can't
-        * insert a translation, so have to emulate the side effects
-        * of the instruction. Since we don't insert a translation
-        * we can get a lot of faults during a flush loop, so it makes
-        * sense to try to do it here with minimum overhead. We only
-        * emulate fdc,fic,pdc,probew,prober instructions whose base 
-        * and index registers are not shadowed. We defer everything 
-        * else to the "slow" path.
+        * Non-access misses can be caused by fdc,fic,pdc,lpa,probe and
+        * probei instructions. The kernel no longer faults doing flushes.
+        * Use of lpa and probe instructions is rare. Given the issue
+        * with shadow registers, we defer everything to the "slow" path.
         */
-
-       mfctl           %cr19,%r9 /* Get iir */
-
-       /* PA 2.0 Arch Ref. Book pg 382 has a good description of the insn bits.
-          Checks for fdc,fdce,pdc,"fic,4f",prober,probeir,probew, probeiw */
-
-       /* Checks for fdc,fdce,pdc,"fic,4f" only */
-       ldi             0x280,%r16
-       and             %r9,%r16,%r17
-       cmpb,<>,n       %r16,%r17,nadtlb_probe_check
-       bb,>=,n         %r9,26,nadtlb_nullify  /* m bit not set, just nullify */
-       BL              get_register,%r25
-       extrw,u         %r9,15,5,%r8           /* Get index register # */
-       cmpib,COND(=),n        -1,%r1,nadtlb_fault    /* have to use slow path */
-       copy            %r1,%r24
-       BL              get_register,%r25
-       extrw,u         %r9,10,5,%r8           /* Get base register # */
-       cmpib,COND(=),n        -1,%r1,nadtlb_fault    /* have to use slow path */
-       BL              set_register,%r25
-       add,l           %r1,%r24,%r1           /* doesn't affect c/b bits */
-
-nadtlb_nullify:
-       mfctl           %ipsw,%r8
-       ldil            L%PSW_N,%r9
-       or              %r8,%r9,%r8            /* Set PSW_N */
-       mtctl           %r8,%ipsw
-
-       rfir
-       nop
-
-       /* 
-               When there is no translation for the probe address then we
-               must nullify the insn and return zero in the target register.
-               This will indicate to the calling code that it does not have 
-               write/read privileges to this address.
-
-               This should technically work for prober and probew in PA 1.1,
-               and also probe,r and probe,w in PA 2.0
-
-               WARNING: USE ONLY NON-SHADOW REGISTERS WITH PROBE INSN!
-               THE SLOW-PATH EMULATION HAS NOT BEEN WRITTEN YET.
-
-       */
-nadtlb_probe_check:
-       ldi             0x80,%r16
-       and             %r9,%r16,%r17
-       cmpb,<>,n       %r16,%r17,nadtlb_fault /* Must be probe,[rw]*/
-       BL              get_register,%r25      /* Find the target register */
-       extrw,u         %r9,31,5,%r8           /* Get target register */
-       cmpib,COND(=),n        -1,%r1,nadtlb_fault    /* have to use slow path */
-       BL              set_register,%r25
-       copy            %r0,%r1                /* Write zero to target register */
-       b nadtlb_nullify                       /* Nullify return insn */
-       nop
-
+       b,n             nadtlb_fault
 
 #ifdef CONFIG_64BIT
 itlb_miss_20w: