diff --git a/arch/powerpc/include/asm/pgtable-ppc32.h b/arch/powerpc/include/asm/pgtable-ppc32.h
index 6ab7c67..f69a4d9 100644
--- a/arch/powerpc/include/asm/pgtable-ppc32.h
+++ b/arch/powerpc/include/asm/pgtable-ppc32.h
@@ -228,9 +228,10 @@
  *   - FILE *must* be in the bottom three bits because swap cache
  *     entries use the top 29 bits for TLB2.
  *
- *   - CACHE COHERENT bit (M) has no effect on PPC440 core, because it
- *     doesn't support SMP. So we can use this as software bit, like
- *     DIRTY.
+ *   - CACHE COHERENT bit (M) has no effect on original PPC440 cores,
+ *     because it doesn't support SMP. However, some later 460 variants
+ *     have -some- form of SMP support and so I keep the bit there for
+ *     future use
  *
  * With the PPC 44x Linux implementation, the 0-11th LSBs of the PTE are used
  * for memory protection related functions (see PTE structure in
@@ -436,20 +437,23 @@
 			 _PAGE_USER | _PAGE_ACCESSED | \
 			 _PAGE_RW | _PAGE_HWWRITE | _PAGE_DIRTY | \
 			 _PAGE_EXEC | _PAGE_HWEXEC)
-/*
- * Note: the _PAGE_COHERENT bit automatically gets set in the hardware
- * PTE if CONFIG_SMP is defined (hash_page does this); there is no need
- * to have it in the Linux PTE, and in fact the bit could be reused for
- * another purpose.  -- paulus.
- */
 
-#ifdef CONFIG_44x
-#define _PAGE_BASE	(_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_GUARDED)
+/*
+ * We define 2 sets of base prot bits, one for basic pages (ie,
+ * cacheable kernel and user pages) and one for non cacheable
+ * pages. We always set _PAGE_COHERENT when SMP is enabled or
+ * the processor might need it for DMA coherency.
+ */
+#if defined(CONFIG_SMP) || defined(CONFIG_PPC_STD_MMU)
+#define _PAGE_BASE	(_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_COHERENT)
 #else
 #define _PAGE_BASE	(_PAGE_PRESENT | _PAGE_ACCESSED)
 #endif
+#define _PAGE_BASE_NC	(_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_NO_CACHE)
+
 #define _PAGE_WRENABLE	(_PAGE_RW | _PAGE_DIRTY | _PAGE_HWWRITE)
 #define _PAGE_KERNEL	(_PAGE_BASE | _PAGE_SHARED | _PAGE_WRENABLE)
+#define _PAGE_KERNEL_NC	(_PAGE_BASE_NC | _PAGE_SHARED | _PAGE_WRENABLE)
 
 #ifdef CONFIG_PPC_STD_MMU
 /* On standard PPC MMU, no user access implies kernel read/write access,
@@ -459,7 +463,7 @@
 #define _PAGE_KERNEL_RO	(_PAGE_BASE | _PAGE_SHARED)
 #endif
 
-#define _PAGE_IO	(_PAGE_KERNEL | _PAGE_NO_CACHE | _PAGE_GUARDED)
+#define _PAGE_IO	(_PAGE_KERNEL_NC | _PAGE_GUARDED)
 #define _PAGE_RAM	(_PAGE_KERNEL | _PAGE_HWEXEC)
 
 #if defined(CONFIG_KGDB) || defined(CONFIG_XMON) || defined(CONFIG_BDI_SWITCH) ||\
@@ -552,9 +556,6 @@
 static inline int pte_file(pte_t pte)		{ return pte_val(pte) & _PAGE_FILE; }
 static inline int pte_special(pte_t pte)	{ return pte_val(pte) & _PAGE_SPECIAL; }
 
-static inline void pte_uncache(pte_t pte)       { pte_val(pte) |= _PAGE_NO_CACHE; }
-static inline void pte_cache(pte_t pte)         { pte_val(pte) &= ~_PAGE_NO_CACHE; }
-
 static inline pte_t pte_wrprotect(pte_t pte) {
 	pte_val(pte) &= ~(_PAGE_RW | _PAGE_HWWRITE); return pte; }
 static inline pte_t pte_mkclean(pte_t pte) {
@@ -693,10 +694,11 @@
 #endif
 }
 
+
 static inline void set_pte_at(struct mm_struct *mm, unsigned long addr,
 			      pte_t *ptep, pte_t pte)
 {
-#if defined(CONFIG_PTE_64BIT) && defined(CONFIG_SMP)
+#if defined(CONFIG_PTE_64BIT) && defined(CONFIG_SMP) && defined(CONFIG_DEBUG_VM)
 	WARN_ON(pte_present(*ptep));
 #endif
 	__set_pte_at(mm, addr, ptep, pte);
@@ -760,16 +762,6 @@
 	__changed;							   \
 })
 
-/*
- * Macro to mark a page protection value as "uncacheable".
- */
-#define pgprot_noncached(prot)	(__pgprot(pgprot_val(prot) | _PAGE_NO_CACHE | _PAGE_GUARDED))
-
-struct file;
-extern pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
-				     unsigned long size, pgprot_t vma_prot);
-#define __HAVE_PHYS_MEM_ACCESS_PROT
-
 #define __HAVE_ARCH_PTE_SAME
 #define pte_same(A,B)	(((pte_val(A) ^ pte_val(B)) & ~_PAGE_HASHPTE) == 0)
 
diff --git a/arch/powerpc/include/asm/pgtable-ppc64.h b/arch/powerpc/include/asm/pgtable-ppc64.h
index 1f0a330..b0f18be 100644
--- a/arch/powerpc/include/asm/pgtable-ppc64.h
+++ b/arch/powerpc/include/asm/pgtable-ppc64.h
@@ -245,9 +245,6 @@
 static inline int pte_file(pte_t pte) { return pte_val(pte) & _PAGE_FILE;}
 static inline int pte_special(pte_t pte) { return pte_val(pte) & _PAGE_SPECIAL; }
 
-static inline void pte_uncache(pte_t pte) { pte_val(pte) |= _PAGE_NO_CACHE; }
-static inline void pte_cache(pte_t pte)   { pte_val(pte) &= ~_PAGE_NO_CACHE; }
-
 static inline pte_t pte_wrprotect(pte_t pte) {
 	pte_val(pte) &= ~(_PAGE_RW); return pte; }
 static inline pte_t pte_mkclean(pte_t pte) {
@@ -405,16 +402,6 @@
 	__changed;							   \
 })
 
-/*
- * Macro to mark a page protection value as "uncacheable".
- */
-#define pgprot_noncached(prot)	(__pgprot(pgprot_val(prot) | _PAGE_NO_CACHE | _PAGE_GUARDED))
-
-struct file;
-extern pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
-				     unsigned long size, pgprot_t vma_prot);
-#define __HAVE_PHYS_MEM_ACCESS_PROT
-
 #define __HAVE_ARCH_PTE_SAME
 #define pte_same(A,B)	(((pte_val(A) ^ pte_val(B)) & ~_PAGE_HPTEFLAGS) == 0)
 
diff --git a/arch/powerpc/include/asm/pgtable.h b/arch/powerpc/include/asm/pgtable.h
index dbb8ca1..07f55e6 100644
--- a/arch/powerpc/include/asm/pgtable.h
+++ b/arch/powerpc/include/asm/pgtable.h
@@ -16,6 +16,32 @@
 #endif
 
 #ifndef __ASSEMBLY__
+
+/*
+ * Macro to mark a page protection value as "uncacheable".
+ */
+
+#define _PAGE_CACHE_CTL	(_PAGE_COHERENT | _PAGE_GUARDED | _PAGE_NO_CACHE | \
+			 _PAGE_WRITETHRU)
+
+#define pgprot_noncached(prot)	  (__pgprot((pgprot_val(prot) & ~_PAGE_CACHE_CTL) | \
+				            _PAGE_NO_CACHE | _PAGE_GUARDED))
+
+#define pgprot_noncached_wc(prot) (__pgprot((pgprot_val(prot) & ~_PAGE_CACHE_CTL) | \
+				            _PAGE_NO_CACHE))
+
+#define pgprot_cached(prot)       (__pgprot((pgprot_val(prot) & ~_PAGE_CACHE_CTL) | \
+				            _PAGE_COHERENT))
+
+#define pgprot_cached_wthru(prot) (__pgprot((pgprot_val(prot) & ~_PAGE_CACHE_CTL) | \
+				            _PAGE_COHERENT | _PAGE_WRITETHRU))
+
+
+struct file;
+extern pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
+				     unsigned long size, pgprot_t vma_prot);
+#define __HAVE_PHYS_MEM_ACCESS_PROT
+
 /*
  * ZERO_PAGE is a global shared page that is always zero: used
  * for zero-mapped memory areas etc..
diff --git a/arch/powerpc/kernel/head_44x.S b/arch/powerpc/kernel/head_44x.S
index f3a1ea9..2623735 100644
--- a/arch/powerpc/kernel/head_44x.S
+++ b/arch/powerpc/kernel/head_44x.S
@@ -570,6 +570,7 @@
 	rlwimi	r10,r12,29,30,30		/* DIRTY -> SW position */
 	and	r11,r12,r10			/* Mask PTE bits to keep */
 	andi.	r10,r12,_PAGE_USER		/* User page ? */
+	ori	r11,r11,_PAGE_GUARDED		/* 440 errata, needs G set */
 	beq	1f				/* nope, leave U bits empty */
 	rlwimi	r11,r11,3,26,28			/* yes, copy S bits to U */
 1:	tlbwe	r11,r13,PPC44x_TLB_ATTRIB	/* Write ATTRIB */
diff --git a/arch/powerpc/kernel/pci-common.c b/arch/powerpc/kernel/pci-common.c
index 1a32db3..2538030 100644
--- a/arch/powerpc/kernel/pci-common.c
+++ b/arch/powerpc/kernel/pci-common.c
@@ -370,13 +370,10 @@
 	}
 
 	/* XXX would be nice to have a way to ask for write-through */
-	prot |= _PAGE_NO_CACHE;
 	if (write_combine)
-		prot &= ~_PAGE_GUARDED;
+		return pgprot_noncached_wc(prot);
 	else
-		prot |= _PAGE_GUARDED;
-
-	return __pgprot(prot);
+		return pgprot_noncached(prot);
 }
 
 /*
@@ -387,19 +384,17 @@
 pgprot_t pci_phys_mem_access_prot(struct file *file,
 				  unsigned long pfn,
 				  unsigned long size,
-				  pgprot_t protection)
+				  pgprot_t prot)
 {
 	struct pci_dev *pdev = NULL;
 	struct resource *found = NULL;
-	unsigned long prot = pgprot_val(protection);
 	resource_size_t offset = ((resource_size_t)pfn) << PAGE_SHIFT;
 	int i;
 
 	if (page_is_ram(pfn))
-		return __pgprot(prot);
+		return prot;
 
-	prot |= _PAGE_NO_CACHE | _PAGE_GUARDED;
-
+	prot = pgprot_noncached(prot);
 	for_each_pci_dev(pdev) {
 		for (i = 0; i <= PCI_ROM_RESOURCE; i++) {
 			struct resource *rp = &pdev->resource[i];
@@ -420,14 +415,14 @@
 	}
 	if (found) {
 		if (found->flags & IORESOURCE_PREFETCH)
-			prot &= ~_PAGE_GUARDED;
+			prot = pgprot_noncached_wc(prot);
 		pci_dev_put(pdev);
 	}
 
 	pr_debug("PCI: Non-PCI map for %llx, prot: %lx\n",
-		 (unsigned long long)offset, prot);
+		 (unsigned long long)offset, pgprot_val(prot));
 
-	return __pgprot(prot);
+	return prot;
 }
 
 
@@ -583,8 +578,7 @@
 	pr_debug(" -> mapping phys %llx\n", (unsigned long long)offset);
 
 	vma->vm_pgoff = offset >> PAGE_SHIFT;
-	vma->vm_page_prot = __pgprot(pgprot_val(vma->vm_page_prot)
-				     | _PAGE_NO_CACHE | _PAGE_GUARDED);
+	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 	return remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff,
 			       vma->vm_end - vma->vm_start,
 			       vma->vm_page_prot);
diff --git a/arch/powerpc/mm/hash_low_32.S b/arch/powerpc/mm/hash_low_32.S
index c8eac22..2884560 100644
--- a/arch/powerpc/mm/hash_low_32.S
+++ b/arch/powerpc/mm/hash_low_32.S
@@ -323,8 +323,8 @@
 	ori	r8,r8,0xe14		/* clear out reserved bits and M */
 	andc	r8,r5,r8		/* PP = user? (rw&dirty? 2: 3): 0 */
 BEGIN_FTR_SECTION
-	ori	r8,r8,_PAGE_COHERENT	/* set M (coherence required) */
-END_FTR_SECTION_IFSET(CPU_FTR_NEED_COHERENT)
+	rlwinm	r8,r8,0,~_PAGE_COHERENT	/* clear M (coherence not required) */
+END_FTR_SECTION_IFCLR(CPU_FTR_NEED_COHERENT)
 #ifdef CONFIG_PTE_64BIT
 	/* Put the XPN bits into the PTE */
 	rlwimi	r8,r10,8,20,22
diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index 8fee696f..53b06eb 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -102,8 +102,8 @@
 		return ppc_md.phys_mem_access_prot(file, pfn, size, vma_prot);
 
 	if (!page_is_ram(pfn))
-		vma_prot = __pgprot(pgprot_val(vma_prot)
-				    | _PAGE_GUARDED | _PAGE_NO_CACHE);
+		vma_prot = pgprot_noncached(vma_prot);
+
 	return vma_prot;
 }
 EXPORT_SYMBOL(phys_mem_access_prot);
diff --git a/arch/powerpc/platforms/cell/spufs/file.c b/arch/powerpc/platforms/cell/spufs/file.c
index 1b26071..7106b63 100644
--- a/arch/powerpc/platforms/cell/spufs/file.c
+++ b/arch/powerpc/platforms/cell/spufs/file.c
@@ -273,12 +273,10 @@
 		return VM_FAULT_NOPAGE;
 
 	if (ctx->state == SPU_STATE_SAVED) {
-		vma->vm_page_prot = __pgprot(pgprot_val(vma->vm_page_prot)
-							& ~_PAGE_NO_CACHE);
+		vma->vm_page_prot = pgprot_cached(vma->vm_page_prot);
 		pfn = vmalloc_to_pfn(ctx->csa.lscsa->ls + offset);
 	} else {
-		vma->vm_page_prot = __pgprot(pgprot_val(vma->vm_page_prot)
-					     | _PAGE_NO_CACHE);
+		vma->vm_page_prot = pgprot_noncached_wc(vma->vm_page_prot);
 		pfn = (ctx->spu->local_store_phys + offset) >> PAGE_SHIFT;
 	}
 	vm_insert_pfn(vma, address, pfn);
@@ -338,8 +336,7 @@
 		return -EINVAL;
 
 	vma->vm_flags |= VM_IO | VM_PFNMAP;
-	vma->vm_page_prot = __pgprot(pgprot_val(vma->vm_page_prot)
-				     | _PAGE_NO_CACHE);
+	vma->vm_page_prot = pgprot_noncached_wc(vma->vm_page_prot);
 
 	vma->vm_ops = &spufs_mem_mmap_vmops;
 	return 0;
@@ -452,8 +449,7 @@
 		return -EINVAL;
 
 	vma->vm_flags |= VM_IO | VM_PFNMAP;
-	vma->vm_page_prot = __pgprot(pgprot_val(vma->vm_page_prot)
-				     | _PAGE_NO_CACHE | _PAGE_GUARDED);
+	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 
 	vma->vm_ops = &spufs_cntl_mmap_vmops;
 	return 0;
@@ -1155,8 +1151,7 @@
 		return -EINVAL;
 
 	vma->vm_flags |= VM_IO | VM_PFNMAP;
-	vma->vm_page_prot = __pgprot(pgprot_val(vma->vm_page_prot)
-				     | _PAGE_NO_CACHE | _PAGE_GUARDED);
+	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 
 	vma->vm_ops = &spufs_signal1_mmap_vmops;
 	return 0;
@@ -1292,8 +1287,7 @@
 		return -EINVAL;
 
 	vma->vm_flags |= VM_IO | VM_PFNMAP;
-	vma->vm_page_prot = __pgprot(pgprot_val(vma->vm_page_prot)
-				     | _PAGE_NO_CACHE | _PAGE_GUARDED);
+	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 
 	vma->vm_ops = &spufs_signal2_mmap_vmops;
 	return 0;
@@ -1414,8 +1408,7 @@
 		return -EINVAL;
 
 	vma->vm_flags |= VM_IO | VM_PFNMAP;
-	vma->vm_page_prot = __pgprot(pgprot_val(vma->vm_page_prot)
-				     | _PAGE_NO_CACHE | _PAGE_GUARDED);
+	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 
 	vma->vm_ops = &spufs_mss_mmap_vmops;
 	return 0;
@@ -1476,8 +1469,7 @@
 		return -EINVAL;
 
 	vma->vm_flags |= VM_IO | VM_PFNMAP;
-	vma->vm_page_prot = __pgprot(pgprot_val(vma->vm_page_prot)
-				     | _PAGE_NO_CACHE | _PAGE_GUARDED);
+	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 
 	vma->vm_ops = &spufs_psmap_mmap_vmops;
 	return 0;
@@ -1536,8 +1528,7 @@
 		return -EINVAL;
 
 	vma->vm_flags |= VM_IO | VM_PFNMAP;
-	vma->vm_page_prot = __pgprot(pgprot_val(vma->vm_page_prot)
-				     | _PAGE_NO_CACHE | _PAGE_GUARDED);
+	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 
 	vma->vm_ops = &spufs_mfc_mmap_vmops;
 	return 0;
diff --git a/drivers/video/controlfb.c b/drivers/video/controlfb.c
index b0be7ea..49fcbe8 100644
--- a/drivers/video/controlfb.c
+++ b/drivers/video/controlfb.c
@@ -298,10 +298,10 @@
                        return -EINVAL;
                start = info->fix.mmio_start;
                len = PAGE_ALIGN((start & ~PAGE_MASK)+info->fix.mmio_len);
-               pgprot_val(vma->vm_page_prot) |= _PAGE_NO_CACHE|_PAGE_GUARDED;
+	       vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
        } else {
                /* framebuffer */
-               pgprot_val(vma->vm_page_prot) |= _PAGE_WRITETHRU;
+	       vma->vm_page_prot = pgprot_cached_wthru(vma->vm_page_prot);
        }
        start &= PAGE_MASK;
        if ((vma->vm_end - vma->vm_start + off) > len)