parisc: flush pages through tmpalias space

The kernel has an 8M tmpailas space (originally designed for copying
and clearing pages but now only used for clearing).  The idea is
to place zeros into the cache above a physical page rather than into
the physical page and flush the cache, because often the zeros end up
being replaced quickly anyway.

We can also use the tmpalias space for flushing a page.  The difference
here is that we have to do tmpalias processing in the non access data and
instruction traps.  The principle is the same: as long as we know the physical
address and have a virtual address congruent to the real one, the flush will
be effective.

In order to use the tmpalias space, the icache miss path has to be enhanced to
check for the alias region to make the fic instruction effective.

Signed-off-by: James Bottomley <James.Bottomley@suse.de>

1 files changed, 142 insertions, 52 deletions

diff --git a/arch/parisc/kernel/entry.S b/arch/parisc/kernel/entry.S
index 6337adef30f6..e8c119b61fc7 100644
--- a/arch/parisc/kernel/entry.S
+++ b/arch/parisc/kernel/entry.S
@@ -225,22 +225,13 @@
 #ifndef CONFIG_64BIT
         /*
          * naitlb miss interruption handler (parisc 1.1 - 32 bit)
-         *
-         * Note: naitlb misses will be treated
-         * as an ordinary itlb miss for now.
-         * However, note that naitlb misses
-         * have the faulting address in the
-         * IOR/ISR.
          */
 
         .macro  naitlb_11 code
 
         mfctl   %isr,spc
-        b       itlb_miss_11
+        b       naitlb_miss_11
         mfctl   %ior,va
-        /* FIXME: If user causes a naitlb miss, the priv level may not be in
-         * lower bits of va, where the itlb miss handler is expecting them
-         */
 
         .align          32
         .endm
@@ -248,26 +239,17 @@
         
         /*
          * naitlb miss interruption handler (parisc 2.0)
-         *
-         * Note: naitlb misses will be treated
-         * as an ordinary itlb miss for now.
-         * However, note that naitlb misses
-         * have the faulting address in the
-         * IOR/ISR.
          */
 
         .macro  naitlb_20 code
 
         mfctl   %isr,spc
 #ifdef CONFIG_64BIT
-        b       itlb_miss_20w
+        b       naitlb_miss_20w
 #else
-        b       itlb_miss_20
+        b       naitlb_miss_20
 #endif
         mfctl   %ior,va
-        /* FIXME: If user causes a naitlb miss, the priv level may not be in
-         * lower bits of va, where the itlb miss handler is expecting them
-         */
 
         .align          32
         .endm
@@ -581,7 +563,24 @@
         copy            \va,\tmp1
         depi            0,31,23,\tmp1
         cmpb,COND(<>),n \tmp,\tmp1,\fault
-        ldi             (_PAGE_DIRTY|_PAGE_WRITE|_PAGE_READ),\prot
+        mfctl           %cr19,\tmp      /* iir */
+        /* get the opcode (first six bits) into \tmp */
+        extrw,u         \tmp,5,6,\tmp
+        /*
+         * Only setting the T bit prevents data cache movein
+         * Setting access rights to zero prevents instruction cache movein
+         *
+         * Note subtlety here: _PAGE_GATEWAY, _PAGE_EXEC and _PAGE_WRITE go
+         * to type field and _PAGE_READ goes to top bit of PL1
+         */
+        ldi             (_PAGE_REFTRAP|_PAGE_READ|_PAGE_WRITE),\prot
+        /*
+         * so if the opcode is one (i.e. this is a memory management
+         * instruction) nullify the next load so \prot is only T.
+         * Otherwise this is a normal data operation
+         */
+        cmpiclr,=       0x01,\tmp,%r0
+        ldi             (_PAGE_DIRTY|_PAGE_READ|_PAGE_WRITE),\prot
         depd,z          \prot,8,7,\prot
         /*
          * OK, it is in the temp alias region, check whether "from" or "to".
@@ -631,11 +630,7 @@ ENTRY(fault_vector_20)
         def             13
         def             14
         dtlb_20         15
-#if 0
         naitlb_20       16
-#else
-        def             16
-#endif
         nadtlb_20       17
         def             18
         def             19
@@ -678,11 +673,7 @@ ENTRY(fault_vector_11)
         def             13
         def             14
         dtlb_11         15
-#if 0
         naitlb_11       16
-#else
-        def             16
-#endif
         nadtlb_11       17
         def             18
         def             19
@@ -1203,7 +1194,7 @@ nadtlb_miss_20w:
         get_pgd         spc,ptp
         space_check     spc,t0,nadtlb_fault
 
-        L3_ptep         ptp,pte,t0,va,nadtlb_check_flush_20w
+        L3_ptep         ptp,pte,t0,va,nadtlb_check_alias_20w
 
         update_ptep     ptp,pte,t0,t1
 
@@ -1214,6 +1205,14 @@ nadtlb_miss_20w:
         rfir
         nop
 
+nadtlb_check_alias_20w:
+        do_alias        spc,t0,t1,va,pte,prot,nadtlb_check_flush_20w
+
+        idtlbt          pte,prot
+
+        rfir
+        nop
+
 nadtlb_check_flush_20w:
         bb,>=,n          pte,_PAGE_FLUSH_BIT,nadtlb_emulate
 
@@ -1255,25 +1254,7 @@ dtlb_miss_11:
         nop
 
 dtlb_check_alias_11:
-
-        /* Check to see if fault is in the temporary alias region */
-
-        cmpib,<>,n      0,spc,dtlb_fault /* forward */
-        ldil            L%(TMPALIAS_MAP_START),t0
-        copy            va,t1
-        depwi           0,31,23,t1
-        cmpb,<>,n       t0,t1,dtlb_fault /* forward */
-        ldi             (_PAGE_DIRTY|_PAGE_WRITE|_PAGE_READ),prot
-        depw,z          prot,8,7,prot
-
-        /*
-         * OK, it is in the temp alias region, check whether "from" or "to".
-         * Check "subtle" note in pacache.S re: r23/r26.
-         */
-
-        extrw,u,=       va,9,1,r0
-        or,tr           %r23,%r0,pte    /* If "from" use "from" page */
-        or              %r26,%r0,pte    /* else "to", use "to" page  */
+        do_alias        spc,t0,t1,va,pte,prot,dtlb_fault
 
         idtlba          pte,(va)
         idtlbp          prot,(va)
@@ -1286,7 +1267,7 @@ nadtlb_miss_11:
 
         space_check     spc,t0,nadtlb_fault
 
-        L2_ptep         ptp,pte,t0,va,nadtlb_check_flush_11
+        L2_ptep         ptp,pte,t0,va,nadtlb_check_alias_11
 
         update_ptep     ptp,pte,t0,t1
 
@@ -1304,6 +1285,15 @@ nadtlb_miss_11:
         rfir
         nop
 
+nadtlb_check_alias_11:
+        do_alias        spc,t0,t1,va,pte,prot,nadtlb_check_flush_11
+
+        idtlba          pte,(va)
+        idtlbp          prot,(va)
+
+        rfir
+        nop
+
 nadtlb_check_flush_11:
         bb,>=,n          pte,_PAGE_FLUSH_BIT,nadtlb_emulate
 
@@ -1359,7 +1349,7 @@ nadtlb_miss_20:
 
         space_check     spc,t0,nadtlb_fault
 
-        L2_ptep         ptp,pte,t0,va,nadtlb_check_flush_20
+        L2_ptep         ptp,pte,t0,va,nadtlb_check_alias_20
 
         update_ptep     ptp,pte,t0,t1
 
@@ -1372,6 +1362,14 @@ nadtlb_miss_20:
         rfir
         nop
 
+nadtlb_check_alias_20:
+        do_alias        spc,t0,t1,va,pte,prot,nadtlb_check_flush_20
+
+        idtlbt          pte,prot
+
+        rfir
+        nop
+
 nadtlb_check_flush_20:
         bb,>=,n          pte,_PAGE_FLUSH_BIT,nadtlb_emulate
 
@@ -1484,6 +1482,36 @@ itlb_miss_20w:
         rfir
         nop
 
+naitlb_miss_20w:
+
+        /*
+         * I miss is a little different, since we allow users to fault
+         * on the gateway page which is in the kernel address space.
+         */
+
+        space_adjust    spc,va,t0
+        get_pgd         spc,ptp
+        space_check     spc,t0,naitlb_fault
+
+        L3_ptep         ptp,pte,t0,va,naitlb_check_alias_20w
+
+        update_ptep     ptp,pte,t0,t1
+
+        make_insert_tlb spc,pte,prot
+
+        iitlbt          pte,prot
+
+        rfir
+        nop
+
+naitlb_check_alias_20w:
+        do_alias        spc,t0,t1,va,pte,prot,naitlb_fault
+
+        iitlbt          pte,prot
+
+        rfir
+        nop
+
 #else
 
 itlb_miss_11:
@@ -1508,6 +1536,38 @@ itlb_miss_11:
         rfir
         nop
 
+naitlb_miss_11:
+        get_pgd         spc,ptp
+
+        space_check     spc,t0,naitlb_fault
+
+        L2_ptep         ptp,pte,t0,va,naitlb_check_alias_11
+
+        update_ptep     ptp,pte,t0,t1
+
+        make_insert_tlb_11      spc,pte,prot
+
+        mfsp            %sr1,t0  /* Save sr1 so we can use it in tlb inserts */
+        mtsp            spc,%sr1
+
+        iitlba          pte,(%sr1,va)
+        iitlbp          prot,(%sr1,va)
+
+        mtsp            t0, %sr1        /* Restore sr1 */
+
+        rfir
+        nop
+
+naitlb_check_alias_11:
+        do_alias        spc,t0,t1,va,pte,prot,itlb_fault
+
+        iitlba          pte,(%sr0, va)
+        iitlbp          prot,(%sr0, va)
+
+        rfir
+        nop
+
+
 itlb_miss_20:
         get_pgd         spc,ptp
 
@@ -1526,6 +1586,32 @@ itlb_miss_20:
         rfir
         nop
 
+naitlb_miss_20:
+        get_pgd         spc,ptp
+
+        space_check     spc,t0,naitlb_fault
+
+        L2_ptep         ptp,pte,t0,va,naitlb_check_alias_20
+
+        update_ptep     ptp,pte,t0,t1
+
+        make_insert_tlb spc,pte,prot
+
+        f_extend        pte,t0
+
+        iitlbt          pte,prot
+
+        rfir
+        nop
+
+naitlb_check_alias_20:
+        do_alias        spc,t0,t1,va,pte,prot,naitlb_fault
+
+        iitlbt          pte,prot
+
+        rfir
+        nop
+
 #endif
 
 #ifdef CONFIG_64BIT
@@ -1662,6 +1748,10 @@ nadtlb_fault:
         b               intr_save
         ldi             17,%r8
 
+naitlb_fault:
+        b               intr_save
+        ldi             16,%r8
+
 dtlb_fault:
         b               intr_save
         ldi             15,%r8