[ARM] mm 8: define mem_types table L1 bit 4 to be for ARMv6

Change the memory types table to define the L1 descriptor bit 4 to
be in terms of the ARMv6 definition - execute never.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/mm/mmu.c

@@ -181,16 +181,16 @@ static struct mem_type mem_types[] = {
 		.prot_pte  = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
 				L_PTE_WRITE,
 		.prot_l1   = PMD_TYPE_TABLE,
-		.prot_sect = PMD_TYPE_SECT | PMD_BIT4 | PMD_SECT_UNCACHED |
+		.prot_sect = PMD_TYPE_SECT | PMD_SECT_XN | PMD_SECT_UNCACHED |
 				PMD_SECT_AP_WRITE,
 		.domain    = DOMAIN_IO,
 	},
 	[MT_CACHECLEAN] = {
-		.prot_sect = PMD_TYPE_SECT | PMD_BIT4,
+		.prot_sect = PMD_TYPE_SECT | PMD_SECT_XN,
 		.domain    = DOMAIN_KERNEL,
 	},
 	[MT_MINICLEAN] = {
-		.prot_sect = PMD_TYPE_SECT | PMD_BIT4 | PMD_SECT_MINICACHE,
+		.prot_sect = PMD_TYPE_SECT | PMD_SECT_XN | PMD_SECT_MINICACHE,
 		.domain    = DOMAIN_KERNEL,
 	},
 	[MT_LOW_VECTORS] = {
@@ -206,25 +206,25 @@ static struct mem_type mem_types[] = {
 		.domain    = DOMAIN_USER,
 	},
 	[MT_MEMORY] = {
-		.prot_sect = PMD_TYPE_SECT | PMD_BIT4 | PMD_SECT_AP_WRITE,
+		.prot_sect = PMD_TYPE_SECT | PMD_SECT_AP_WRITE,
 		.domain    = DOMAIN_KERNEL,
 	},
 	[MT_ROM] = {
-		.prot_sect = PMD_TYPE_SECT | PMD_BIT4,
+		.prot_sect = PMD_TYPE_SECT,
 		.domain    = DOMAIN_KERNEL,
 	},
 	[MT_IXP2000_DEVICE] = { /* IXP2400 requires XCB=101 for on-chip I/O */
 		.prot_pte  = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
 				L_PTE_WRITE,
 		.prot_l1   = PMD_TYPE_TABLE,
-		.prot_sect = PMD_TYPE_SECT | PMD_BIT4 | PMD_SECT_UNCACHED |
+		.prot_sect = PMD_TYPE_SECT | PMD_SECT_XN | PMD_SECT_UNCACHED |
 				PMD_SECT_AP_WRITE | PMD_SECT_BUFFERABLE |
 				PMD_SECT_TEX(1),
 		.domain    = DOMAIN_IO,
 	},
 	[MT_NONSHARED_DEVICE] = {
 		.prot_l1   = PMD_TYPE_TABLE,
-		.prot_sect = PMD_TYPE_SECT | PMD_BIT4 | PMD_SECT_NONSHARED_DEV |
+		.prot_sect = PMD_TYPE_SECT | PMD_SECT_XN | PMD_SECT_NONSHARED_DEV |
 				PMD_SECT_AP_WRITE,
 		.domain    = DOMAIN_IO,
 	}
@@ -260,20 +260,23 @@ static void __init build_mem_type_table(void)
 	}
 
 	/*
-	 * Xscale must not have PMD bit 4 set for section mappings.
+	 * ARMv5 and lower, bit 4 must be set for page tables.
+	 * (was: cache "update-able on write" bit on ARM610)
+	 * However, Xscale cores require this bit to be cleared.
 	 */
-	if (cpu_is_xscale())
-		for (i = 0; i < ARRAY_SIZE(mem_types); i++)
+	if (cpu_is_xscale()) {
+		for (i = 0; i < ARRAY_SIZE(mem_types); i++) {
 			mem_types[i].prot_sect &= ~PMD_BIT4;
-
-	/*
-	 * ARMv5 and lower, excluding Xscale, bit 4 must be set for
-	 * page tables.
-	 */
-	if (cpu_arch < CPU_ARCH_ARMv6 && !cpu_is_xscale())
-		for (i = 0; i < ARRAY_SIZE(mem_types); i++)
+			mem_types[i].prot_l1 &= ~PMD_BIT4;
+		}
+	} else if (cpu_arch < CPU_ARCH_ARMv6) {
+		for (i = 0; i < ARRAY_SIZE(mem_types); i++) {
 			if (mem_types[i].prot_l1)
 				mem_types[i].prot_l1 |= PMD_BIT4;
+			if (mem_types[i].prot_sect)
+				mem_types[i].prot_sect |= PMD_BIT4;
+		}
+	}
 
 	cp = &cache_policies[cachepolicy];
 	kern_pgprot = user_pgprot = cp->pte;
@@ -293,13 +296,6 @@ static void __init build_mem_type_table(void)
 	 * ARMv6 and above have extended page tables.
 	 */
 	if (cpu_arch >= CPU_ARCH_ARMv6 && (cr & CR_XP)) {
-		/*
-		 * bit 4 becomes XN which we must clear for the
-		 * kernel memory mapping.
-		 */
-		mem_types[MT_MEMORY].prot_sect &= ~PMD_SECT_XN;
-		mem_types[MT_ROM].prot_sect &= ~PMD_SECT_XN;
-
 		/*
 		 * Mark cache clean areas and XIP ROM read only
 		 * from SVC mode and no access from userspace.