3 files changed, 35 insertions, 10 deletions

diff --git a/arch/x86/kernel/cpu/mtrr/generic.c b/arch/x86/kernel/cpu/mtrr/generic.c
index f782d9b62cb3..3b533cf37c74 100644
--- a/arch/x86/kernel/cpu/mtrr/generic.c
+++ b/arch/x86/kernel/cpu/mtrr/generic.c
@@ -445,7 +445,7 @@ static void __init print_mtrr_state(void)
 }
 
 /* Grab all of the MTRR state for this CPU into *state */
-void __init get_mtrr_state(void)
+bool __init get_mtrr_state(void)
 {
         struct mtrr_var_range *vrs;
         unsigned long flags;
@@ -489,6 +489,8 @@ void __init get_mtrr_state(void)
 
         post_set();
         local_irq_restore(flags);
+
+        return !!(mtrr_state.enabled & MTRR_STATE_MTRR_ENABLED);
 }
 
 /* Some BIOS's are messed up and don't set all MTRRs the same! */
diff --git a/arch/x86/kernel/cpu/mtrr/main.c b/arch/x86/kernel/cpu/mtrr/main.c
index 81baf5fee0e1..383efb26e516 100644
--- a/arch/x86/kernel/cpu/mtrr/main.c
+++ b/arch/x86/kernel/cpu/mtrr/main.c
@@ -59,6 +59,12 @@
 #define MTRR_TO_PHYS_WC_OFFSET 1000
 
 u32 num_var_ranges;
+static bool __mtrr_enabled;
+
+static bool mtrr_enabled(void)
+{
+        return __mtrr_enabled;
+}
 
 unsigned int mtrr_usage_table[MTRR_MAX_VAR_RANGES];
 static DEFINE_MUTEX(mtrr_mutex);
@@ -286,7 +292,7 @@ int mtrr_add_page(unsigned long base, unsigned long size,
         int i, replace, error;
         mtrr_type ltype;
 
-        if (!mtrr_if)
+        if (!mtrr_enabled())
                 return -ENXIO;
 
         error = mtrr_if->validate_add_page(base, size, type);
@@ -435,6 +441,8 @@ static int mtrr_check(unsigned long base, unsigned long size)
 int mtrr_add(unsigned long base, unsigned long size, unsigned int type,
              bool increment)
 {
+        if (!mtrr_enabled())
+                return -ENODEV;
         if (mtrr_check(base, size))
                 return -EINVAL;
         return mtrr_add_page(base >> PAGE_SHIFT, size >> PAGE_SHIFT, type,
@@ -463,8 +471,8 @@ int mtrr_del_page(int reg, unsigned long base, unsigned long size)
         unsigned long lbase, lsize;
         int error = -EINVAL;
 
-        if (!mtrr_if)
-                return -ENXIO;
+        if (!mtrr_enabled())
+                return -ENODEV;
 
         max = num_var_ranges;
         /* No CPU hotplug when we change MTRR entries */
@@ -523,6 +531,8 @@ int mtrr_del_page(int reg, unsigned long base, unsigned long size)
  */
 int mtrr_del(int reg, unsigned long base, unsigned long size)
 {
+        if (!mtrr_enabled())
+                return -ENODEV;
         if (mtrr_check(base, size))
                 return -EINVAL;
         return mtrr_del_page(reg, base >> PAGE_SHIFT, size >> PAGE_SHIFT);
@@ -548,7 +558,7 @@ int arch_phys_wc_add(unsigned long base, unsigned long size)
 {
         int ret;
 
-        if (pat_enabled)
+        if (pat_enabled || !mtrr_enabled())
                 return 0;  /* Success!  (We don't need to do anything.) */
 
         ret = mtrr_add(base, size, MTRR_TYPE_WRCOMB, true);
@@ -737,10 +747,12 @@ void __init mtrr_bp_init(void)
         }
 
         if (mtrr_if) {
+                __mtrr_enabled = true;
                 set_num_var_ranges();
                 init_table();
                 if (use_intel()) {
-                        get_mtrr_state();
+                        /* BIOS may override */
+                        __mtrr_enabled = get_mtrr_state();
 
                         if (mtrr_cleanup(phys_addr)) {
                                 changed_by_mtrr_cleanup = 1;
@@ -748,10 +760,16 @@ void __init mtrr_bp_init(void)
                         }
                 }
         }
+
+        if (!mtrr_enabled())
+                pr_info("MTRR: Disabled\n");
 }
 
 void mtrr_ap_init(void)
 {
+        if (!mtrr_enabled())
+                return;
+
         if (!use_intel() || mtrr_aps_delayed_init)
                 return;
         /*
@@ -777,6 +795,9 @@ void mtrr_save_state(void)
 {
         int first_cpu;
 
+        if (!mtrr_enabled())
+                return;
+
         get_online_cpus();
         first_cpu = cpumask_first(cpu_online_mask);
         smp_call_function_single(first_cpu, mtrr_save_fixed_ranges, NULL, 1);
@@ -785,6 +806,8 @@ void mtrr_save_state(void)
 
 void set_mtrr_aps_delayed_init(void)
 {
+        if (!mtrr_enabled())
+                return;
         if (!use_intel())
                 return;
 
@@ -796,7 +819,7 @@ void set_mtrr_aps_delayed_init(void)
  */
 void mtrr_aps_init(void)
 {
-        if (!use_intel())
+        if (!use_intel() || !mtrr_enabled())
                 return;
 
         /*
@@ -813,7 +836,7 @@ void mtrr_aps_init(void)
 
 void mtrr_bp_restore(void)
 {
-        if (!use_intel())
+        if (!use_intel() || !mtrr_enabled())
                 return;
 
         mtrr_if->set_all();
@@ -821,7 +844,7 @@ void mtrr_bp_restore(void)
 
 static int __init mtrr_init_finialize(void)
 {
-        if (!mtrr_if)
+        if (!mtrr_enabled())
                 return 0;
 
         if (use_intel()) {
diff --git a/arch/x86/kernel/cpu/mtrr/mtrr.h b/arch/x86/kernel/cpu/mtrr/mtrr.h
index df5e41f31a27..951884dcc433 100644
--- a/arch/x86/kernel/cpu/mtrr/mtrr.h
+++ b/arch/x86/kernel/cpu/mtrr/mtrr.h
@@ -51,7 +51,7 @@ void set_mtrr_prepare_save(struct set_mtrr_context *ctxt);
 
 void fill_mtrr_var_range(unsigned int index,
                 u32 base_lo, u32 base_hi, u32 mask_lo, u32 mask_hi);
-void get_mtrr_state(void);
+bool get_mtrr_state(void);
 
 extern void set_mtrr_ops(const struct mtrr_ops *ops);