parisc: Remove PTE load and fault check from L2_ptep macro

This change removes the PTE load and present check from the L2_ptep
macro.  The load and check for kernel pages is now done in the tlb_lock
macro.  This avoids a double load and check for user pages.  The load
and check for user pages is now done inside the lock so the fault
handler can't be called while the entry is being updated.  This version
uses an ordered store to release the lock when the page table entry
isn't present.  It also corrects the check in the non SMP case.

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 04367b2..00ac988 100644 (file)
--- a/arch/parisc/kernel/entry.S
+++ b/arch/parisc/kernel/entry.S
@@ -431,8 +431,6 @@
        extru           \va,31-PAGE_SHIFT,ASM_BITS_PER_PTE,\index
        dep             %r0,31,PAGE_SHIFT,\pmd  /* clear offset */
        shladd          \index,BITS_PER_PTE_ENTRY,\pmd,\pmd /* pmd is now pte */
-       LDREG           %r0(\pmd),\pte
-       bb,>=,n         \pte,_PAGE_PRESENT_BIT,\fault
        .endm
 
        /* Look up PTE in a 3-Level scheme.
@@ -463,7 +461,7 @@
        L2_ptep         \pgd,\pte,\index,\va,\fault
        .endm
 
-       /* Acquire pa_tlb_lock lock and recheck page is still present. */
+       /* Acquire pa_tlb_lock lock and check page is present. */
        .macro          tlb_lock        spc,ptp,pte,tmp,tmp1,fault
 #ifdef CONFIG_SMP
        cmpib,COND(=),n 0,\spc,2f
@@ -472,11 +470,13 @@
        cmpib,COND(=)   0,\tmp1,1b
        nop
        LDREG           0(\ptp),\pte
-       bb,<,n          \pte,_PAGE_PRESENT_BIT,2f
+       bb,<,n          \pte,_PAGE_PRESENT_BIT,3f
        b               \fault
-       stw              \spc,0(\tmp)
-2:
+       stw,ma          \spc,0(\tmp)
 #endif
+2:     LDREG           0(\ptp),\pte
+       bb,>=,n         \pte,_PAGE_PRESENT_BIT,\fault
+3:
        .endm
 
        /* Release pa_tlb_lock lock without reloading lock address. */