mips64 LOAD_KPTE2 fix

[Atsushi Nemoto <anemo@mba.ocn.ne.jp>]

If a TLB exception occured on very high address (such as
0xffffffffffffffff), invalid_vmalloc_address should be called but
currently not.

I think it is because LOAD_KPTE2 in arch/mips64/mm/tlbex-r4k.S does
not check overflow of (kptbl + offset).  Here is a patch (both 2.4 and
2.5).


diff -u linux-mips-cvs/arch/mips64/mm/tlbex-r4k.S 
linux.new/arch/mips64/mm/tlbex-r4k.S
--- linux-mips-cvs/arch/mips64/mm/tlbex-r4k.S   Mon Apr 28 09:44:54 2003
+++ linux.new/arch/mips64/mm/tlbex-r4k.S        Mon Jun  2 19:44:57 2003
@@ -72,6 +72,8 @@
        /*
         * Determine that fault address is within vmalloc range.
         */
+       bgez    \ptr, \not_vmalloc              # check overflow
+       nop
        dla     \tmp, ekptbl
        sltu    \tmp, \ptr, \tmp
        beqz    \tmp, \not_vmalloc              # not vmalloc
---
Atsushi Nemoto