ARM: provide common method to clear bits in CPU control register

Several places open-code this manipulation, let's consolidate this.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

arch/arm/mm/alignment.c

@@ -28,6 +28,7 @@
 #include <asm/opcodes.h>
 
 #include "fault.h"
+#include "mm.h"
 
 /*
  * 32-bit misaligned trap handler (c) 1998 San Mehat (CCC) -July 1998
@@ -968,9 +969,7 @@ static int __init alignment_init(void)
 
 #ifdef CONFIG_CPU_CP15
 	if (cpu_is_v6_unaligned()) {
-		cr_alignment &= ~CR_A;
-		cr_no_alignment &= ~CR_A;
-		set_cr(cr_alignment);
+		set_cr(__clear_cr(CR_A));
 		ai_usermode = safe_usermode(ai_usermode, false);
 	}
 #endif

arch/arm/mm/init.c

@@ -23,6 +23,7 @@
 #include <linux/dma-contiguous.h>
 #include <linux/sizes.h>
 
+#include <asm/cp15.h>
 #include <asm/mach-types.h>
 #include <asm/memblock.h>
 #include <asm/prom.h>
@@ -36,6 +37,15 @@
 
 #include "mm.h"
 
+#ifdef CONFIG_CPU_CP15_MMU
+unsigned long __init __clear_cr(unsigned long mask)
+{
+	cr_no_alignment = cr_no_alignment & ~mask;
+	cr_alignment = cr_alignment & ~mask;
+	return cr_alignment;
+}
+#endif
+
 static phys_addr_t phys_initrd_start __initdata = 0;
 static unsigned long phys_initrd_size __initdata = 0;
 

arch/arm/mm/mm.h

@@ -2,6 +2,8 @@
 #include <linux/list.h>
 #include <linux/vmalloc.h>
 
+#include <asm/pgtable.h>
+
 /* the upper-most page table pointer */
 extern pmd_t *top_pmd;
 
@@ -93,3 +95,5 @@ extern phys_addr_t arm_lowmem_limit;
 void __init bootmem_init(void);
 void arm_mm_memblock_reserve(void);
 void dma_contiguous_remap(void);
+
+unsigned long __clear_cr(unsigned long mask);

arch/arm/mm/mmu.c

@@ -125,6 +125,7 @@ static struct cachepolicy cache_policies[] __initdata = {
  */
 static int __init early_cachepolicy(char *p)
 {
+	unsigned long cr = get_cr();
 	int i;
 
 	for (i = 0; i < ARRAY_SIZE(cache_policies); i++) {
@@ -132,8 +133,7 @@ static int __init early_cachepolicy(char *p)
 
 		if (memcmp(p, cache_policies[i].policy, len) == 0) {
 			cachepolicy = i;
-			cr_alignment &= ~cache_policies[i].cr_mask;
-			cr_no_alignment &= ~cache_policies[i].cr_mask;
+			cr = __clear_cr(cache_policies[i].cr_mask);
 			break;
 		}
 	}
@@ -151,7 +151,7 @@ static int __init early_cachepolicy(char *p)
 		cachepolicy = CPOLICY_WRITEBACK;
 	}
 	flush_cache_all();
-	set_cr(cr_alignment);
+	set_cr(cr);
 	return 0;
 }
 early_param("cachepolicy", early_cachepolicy);
@@ -188,9 +188,7 @@ early_param("ecc", early_ecc);
 
 static int __init noalign_setup(char *__unused)
 {
-	cr_alignment &= ~CR_A;
-	cr_no_alignment &= ~CR_A;
-	set_cr(cr_alignment);
+	set_cr(__clear_cr(CR_A));
 	return 1;
 }
 __setup("noalign", noalign_setup);