2 files changed, 55 insertions, 20 deletions

diff --git a/arch/x86/kernel/cpu/mtrr/if.c b/arch/x86/kernel/cpu/mtrr/if.c
index 08b6ea4c62b4..3c1b12d461d1 100644
--- a/arch/x86/kernel/cpu/mtrr/if.c
+++ b/arch/x86/kernel/cpu/mtrr/if.c
@@ -96,17 +96,24 @@ mtrr_write(struct file *file, const char __user *buf, size_t len, loff_t * ppos)
 	unsigned long long base, size;
 	char *ptr;
 	char line[LINE_SIZE];
+	int length;
 	size_t linelen;
 
 	if (!capable(CAP_SYS_ADMIN))
 		return -EPERM;
-	if (!len)
-		return -EINVAL;
 
 	memset(line, 0, LINE_SIZE);
-	if (len > LINE_SIZE)
-		len = LINE_SIZE;
-	if (copy_from_user(line, buf, len - 1))
+
+	length = len;
+	length--;
+
+	if (length > LINE_SIZE - 1)
+		length = LINE_SIZE - 1;
+
+	if (length < 0)
+		return -EINVAL;
+
+	if (copy_from_user(line, buf, length))
 		return -EFAULT;
 
 	linelen = strlen(line);
@@ -126,8 +133,8 @@ mtrr_write(struct file *file, const char __user *buf, size_t len, loff_t * ppos)
 		return -EINVAL;
 
 	base = simple_strtoull(line + 5, &ptr, 0);
-	for (; isspace(*ptr); ++ptr)
-		;
+	while (isspace(*ptr))
+		ptr++;
 
 	if (strncmp(ptr, "size=", 5))
 		return -EINVAL;
@@ -135,14 +142,14 @@ mtrr_write(struct file *file, const char __user *buf, size_t len, loff_t * ppos)
 	size = simple_strtoull(ptr + 5, &ptr, 0);
 	if ((base & 0xfff) || (size & 0xfff))
 		return -EINVAL;
-	for (; isspace(*ptr); ++ptr)
-		;
+	while (isspace(*ptr))
+		ptr++;
 
 	if (strncmp(ptr, "type=", 5))
 		return -EINVAL;
 	ptr += 5;
-	for (; isspace(*ptr); ++ptr)
-		;
+	while (isspace(*ptr))
+		ptr++;
 
 	for (i = 0; i < MTRR_NUM_TYPES; ++i) {
 		if (strcmp(ptr, mtrr_strings[i]))
diff --git a/arch/x86/kernel/cpu/mtrr/main.c b/arch/x86/kernel/cpu/mtrr/main.c
index 7af0f88a4163..84e83de54575 100644
--- a/arch/x86/kernel/cpu/mtrr/main.c
+++ b/arch/x86/kernel/cpu/mtrr/main.c
@@ -58,6 +58,7 @@ unsigned int mtrr_usage_table[MTRR_MAX_VAR_RANGES];
 static DEFINE_MUTEX(mtrr_mutex);
 
 u64 size_or_mask, size_and_mask;
+static bool mtrr_aps_delayed_init;
 
 static struct mtrr_ops *mtrr_ops[X86_VENDOR_NUM];
 
@@ -163,7 +164,10 @@ static void ipi_handler(void *info)
 	if (data->smp_reg != ~0U) {
 		mtrr_if->set(data->smp_reg, data->smp_base,
 			     data->smp_size, data->smp_type);
-	} else {
+	} else if (mtrr_aps_delayed_init) {
+		/*
+		 * Initialize the MTRRs inaddition to the synchronisation.
+		 */
 		mtrr_if->set_all();
 	}
 
@@ -265,6 +269,8 @@ set_mtrr(unsigned int reg, unsigned long base, unsigned long size, mtrr_type typ
 	 */
 	if (reg != ~0U)
 		mtrr_if->set(reg, base, size, type);
+	else if (!mtrr_aps_delayed_init)
+		mtrr_if->set_all();
 
 	/* Wait for the others */
 	while (atomic_read(&data.count))
@@ -721,9 +727,7 @@ void __init mtrr_bp_init(void)
 
 void mtrr_ap_init(void)
 {
-	unsigned long flags;
-
-	if (!mtrr_if || !use_intel())
+	if (!use_intel() || mtrr_aps_delayed_init)
 		return;
 	/*
 	 * Ideally we should hold mtrr_mutex here to avoid mtrr entries
@@ -738,11 +742,7 @@ void mtrr_ap_init(void)
 	 *   2. cpu hotadd time. We let mtrr_add/del_page hold cpuhotplug
 	 *      lock to prevent mtrr entry changes
 	 */
-	local_irq_save(flags);
-
-	mtrr_if->set_all();
-
-	local_irq_restore(flags);
+	set_mtrr(~0U, 0, 0, 0);
 }
 
 /**
@@ -753,6 +753,34 @@ void mtrr_save_state(void)
 	smp_call_function_single(0, mtrr_save_fixed_ranges, NULL, 1);
 }
 
+void set_mtrr_aps_delayed_init(void)
+{
+	if (!use_intel())
+		return;
+
+	mtrr_aps_delayed_init = true;
+}
+
+/*
+ * MTRR initialization for all AP's
+ */
+void mtrr_aps_init(void)
+{
+	if (!use_intel())
+		return;
+
+	set_mtrr(~0U, 0, 0, 0);
+	mtrr_aps_delayed_init = false;
+}
+
+void mtrr_bp_restore(void)
+{
+	if (!use_intel())
+		return;
+
+	mtrr_if->set_all();
+}
+
 static int __init mtrr_init_finialize(void)
 {
 	if (!mtrr_if)