powerpc/8xx: set PTE bit 22 off TLBmiss

No need to re-set this bit at each TLB miss. Let's set it in the PTE.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Scott Wood <scottwood@freescale.com>

3 files changed, 27 insertions, 10 deletions

diff --git a/arch/powerpc/include/asm/pgtable-ppc32.h b/arch/powerpc/include/asm/pgtable-ppc32.h
index 945e47adf7db..234e07c47803 100644
--- a/arch/powerpc/include/asm/pgtable-ppc32.h
+++ b/arch/powerpc/include/asm/pgtable-ppc32.h
@@ -170,6 +170,25 @@ static inline unsigned long pte_update(pte_t *p,
 #ifdef PTE_ATOMIC_UPDATES
         unsigned long old, tmp;
 
+#ifdef CONFIG_PPC_8xx
+        unsigned long tmp2;
+
+        __asm__ __volatile__("\
+1:      lwarx   %0,0,%4\n\
+        andc    %1,%0,%5\n\
+        or      %1,%1,%6\n\
+        /* 0x200 == Extended encoding, bit 22 */ \
+        /* Bit 22 has to be 1 if neither _PAGE_USER nor _PAGE_RW are set */ \
+        rlwimi  %1,%1,32-2,0x200\n /* get _PAGE_USER */ \
+        rlwinm  %3,%1,32-1,0x200\n /* get _PAGE_RW */ \
+        or      %1,%3,%1\n\
+        xori    %1,%1,0x200\n"
+"       stwcx.  %1,0,%4\n\
+        bne-    1b"
+        : "=&r" (old), "=&r" (tmp), "=m" (*p), "=&r" (tmp2)
+        : "r" (p), "r" (clr), "r" (set), "m" (*p)
+        : "cc" );
+#else /* CONFIG_PPC_8xx */
         __asm__ __volatile__("\
 1:      lwarx   %0,0,%3\n\
         andc    %1,%0,%4\n\
@@ -180,6 +199,7 @@ static inline unsigned long pte_update(pte_t *p,
         : "=&r" (old), "=&r" (tmp), "=m" (*p)
         : "r" (p), "r" (clr), "r" (set), "m" (*p)
         : "cc" );
+#endif /* CONFIG_PPC_8xx */
 #else /* PTE_ATOMIC_UPDATES */
         unsigned long old = pte_val(*p);
         *p = __pte((old & ~clr) | set);
diff --git a/arch/powerpc/include/asm/pte-8xx.h b/arch/powerpc/include/asm/pte-8xx.h
index d44826e4ff97..daa4616e61c4 100644
--- a/arch/powerpc/include/asm/pte-8xx.h
+++ b/arch/powerpc/include/asm/pte-8xx.h
@@ -48,19 +48,22 @@
  */
 #define _PAGE_RW        0x0400  /* lsb PP bits, inverted in HW */
 #define _PAGE_USER      0x0800  /* msb PP bits */
+/* set when neither _PAGE_USER nor _PAGE_RW are set */
+#define _PAGE_KNLRO     0x0200
 
 #define _PMD_PRESENT    0x0001
 #define _PMD_BAD        0x0ff0
 #define _PMD_PAGE_MASK  0x000c
 #define _PMD_PAGE_8M    0x000c
 
-#define _PTE_NONE_MASK _PAGE_ACCESSED
+#define _PTE_NONE_MASK _PAGE_KNLRO
 
 /* Until my rework is finished, 8xx still needs atomic PTE updates */
 #define PTE_ATOMIC_UPDATES      1
 
 /* We need to add _PAGE_SHARED to kernel pages */
-#define _PAGE_KERNEL_RO (_PAGE_SHARED)
+#define _PAGE_KERNEL_RO (_PAGE_SHARED | _PAGE_KNLRO)
+#define _PAGE_KERNEL_ROX        (_PAGE_EXEC | _PAGE_KNLRO)
 #define _PAGE_KERNEL_RW (_PAGE_DIRTY | _PAGE_RW | _PAGE_HWWRITE)
 
 #endif /* __KERNEL__ */
diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S
index 6e9124177f19..8d6e6830a675 100644
--- a/arch/powerpc/kernel/head_8xx.S
+++ b/arch/powerpc/kernel/head_8xx.S
@@ -447,14 +447,8 @@ DataStoreTLBMiss:
         and     r11, r11, r10
         rlwimi  r10, r11, 0, _PAGE_PRESENT
 #endif
-        /* Honour kernel RO, User NA */
-        /* 0x200 == Extended encoding, bit 22 */
-        rlwimi  r10, r10, 32-2, 0x200 /* Copy USER to bit 22, 0x200 */
-        /* r11 =  (r10 & _PAGE_RW) >> 1 */
-        rlwinm  r11, r10, 32-1, 0x200
-        or      r10, r11, r10
-        /* invert RW and 0x200 bits */
-        xori    r10, r10, _PAGE_RW | 0x200
+        /* invert RW */
+        xori    r10, r10, _PAGE_RW
 
         /* The Linux PTE won't go exactly into the MMU TLB.
          * Software indicator bits 22 and 28 must be clear.