1 files changed, 64 insertions, 51 deletions

diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index 82ea2b3fb9b5..ab14b79b03f0 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -118,28 +118,54 @@ static struct cachepolicy cache_policies[] __initdata = {
 };
 
 #ifdef CONFIG_CPU_CP15
+static unsigned long initial_pmd_value __initdata = 0;
+
 /*
- * These are useful for identifying cache coherency
- * problems by allowing the cache or the cache and
- * writebuffer to be turned off.  (Note: the write
- * buffer should not be on and the cache off).
+ * Initialise the cache_policy variable with the initial state specified
+ * via the "pmd" value.  This is used to ensure that on ARMv6 and later,
+ * the C code sets the page tables up with the same policy as the head
+ * assembly code, which avoids an illegal state where the TLBs can get
+ * confused.  See comments in early_cachepolicy() for more information.
  */
-static int __init early_cachepolicy(char *p)
+void __init init_default_cache_policy(unsigned long pmd)
 {
 	int i;
 
+	initial_pmd_value = pmd;
+
+	pmd &= PMD_SECT_TEX(1) | PMD_SECT_BUFFERABLE | PMD_SECT_CACHEABLE;
+
+	for (i = 0; i < ARRAY_SIZE(cache_policies); i++)
+		if (cache_policies[i].pmd == pmd) {
+			cachepolicy = i;
+			break;
+		}
+
+	if (i == ARRAY_SIZE(cache_policies))
+		pr_err("ERROR: could not find cache policy\n");
+}
+
+/*
+ * These are useful for identifying cache coherency problems by allowing
+ * the cache or the cache and writebuffer to be turned off.  (Note: the
+ * write buffer should not be on and the cache off).
+ */
+static int __init early_cachepolicy(char *p)
+{
+	int i, selected = -1;
+
 	for (i = 0; i < ARRAY_SIZE(cache_policies); i++) {
 		int len = strlen(cache_policies[i].policy);
 
 		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;
+			selected = i;
 			break;
 		}
 	}
-	if (i == ARRAY_SIZE(cache_policies))
-		printk(KERN_ERR "ERROR: unknown or unsupported cache policy\n");
+
+	if (selected == -1)
+		pr_err("ERROR: unknown or unsupported cache policy\n");
+
 	/*
 	 * This restriction is partly to do with the way we boot; it is
 	 * unpredictable to have memory mapped using two different sets of
@@ -147,12 +173,18 @@ static int __init early_cachepolicy(char *p)
 	 * change these attributes once the initial assembly has setup the
 	 * page tables.
 	 */
-	if (cpu_architecture() >= CPU_ARCH_ARMv6) {
-		printk(KERN_WARNING "Only cachepolicy=writeback supported on ARMv6 and later\n");
-		cachepolicy = CPOLICY_WRITEBACK;
+	if (cpu_architecture() >= CPU_ARCH_ARMv6 && selected != cachepolicy) {
+		pr_warn("Only cachepolicy=%s supported on ARMv6 and later\n",
+			cache_policies[cachepolicy].policy);
+		return 0;
+	}
+
+	if (selected != cachepolicy) {
+		unsigned long cr = __clear_cr(cache_policies[selected].cr_mask);
+		cachepolicy = selected;
+		flush_cache_all();
+		set_cr(cr);
 	}
-	flush_cache_all();
-	set_cr(cr_alignment);
 	return 0;
 }
 early_param("cachepolicy", early_cachepolicy);
@@ -187,35 +219,6 @@ static int __init early_ecc(char *p)
 early_param("ecc", early_ecc);
 #endif
 
-static int __init noalign_setup(char *__unused)
-{
-	cr_alignment &= ~CR_A;
-	cr_no_alignment &= ~CR_A;
-	set_cr(cr_alignment);
-	return 1;
-}
-__setup("noalign", noalign_setup);
-
-#ifndef CONFIG_SMP
-void adjust_cr(unsigned long mask, unsigned long set)
-{
-	unsigned long flags;
-
-	mask &= ~CR_A;
-
-	set &= mask;
-
-	local_irq_save(flags);
-
-	cr_no_alignment = (cr_no_alignment & ~mask) | set;
-	cr_alignment = (cr_alignment & ~mask) | set;
-
-	set_cr((get_cr() & ~mask) | set);
-
-	local_irq_restore(flags);
-}
-#endif
-
 #else /* ifdef CONFIG_CPU_CP15 */
 
 static int __init early_cachepolicy(char *p)
@@ -415,8 +418,17 @@ static void __init build_mem_type_table(void)
 			cachepolicy = CPOLICY_WRITEBACK;
 		ecc_mask = 0;
 	}
-	if (is_smp())
-		cachepolicy = CPOLICY_WRITEALLOC;
+
+	if (is_smp()) {
+		if (cachepolicy != CPOLICY_WRITEALLOC) {
+			pr_warn("Forcing write-allocate cache policy for SMP\n");
+			cachepolicy = CPOLICY_WRITEALLOC;
+		}
+		if (!(initial_pmd_value & PMD_SECT_S)) {
+			pr_warn("Forcing shared mappings for SMP\n");
+			initial_pmd_value |= PMD_SECT_S;
+		}
+	}
 
 	/*
 	 * Strip out features not present on earlier architectures.
@@ -540,11 +552,12 @@ static void __init build_mem_type_table(void)
 		mem_types[MT_CACHECLEAN].prot_sect |= PMD_SECT_APX|PMD_SECT_AP_WRITE;
 #endif
 
-		if (is_smp()) {
-			/*
-			 * Mark memory with the "shared" attribute
-			 * for SMP systems
-			 */
+		/*
+		 * If the initial page tables were created with the S bit
+		 * set, then we need to do the same here for the same
+		 * reasons given in early_cachepolicy().
+		 */
+		if (initial_pmd_value & PMD_SECT_S) {
 			user_pgprot |= L_PTE_SHARED;
 			kern_pgprot |= L_PTE_SHARED;
 			vecs_pgprot |= L_PTE_SHARED;