1 files changed, 29 insertions, 11 deletions

diff --git a/arch/x86/kernel/cpu/mtrr/main.c b/arch/x86/kernel/cpu/mtrr/main.c
index 01c0f3ee6cc3..929739a653d1 100644
--- a/arch/x86/kernel/cpu/mtrr/main.c
+++ b/arch/x86/kernel/cpu/mtrr/main.c
@@ -45,6 +45,7 @@
 #include <linux/cpu.h>
 #include <linux/pci.h>
 #include <linux/smp.h>
+#include <linux/syscore_ops.h>
 
 #include <asm/processor.h>
 #include <asm/e820.h>
@@ -292,14 +293,24 @@ set_mtrr(unsigned int reg, unsigned long base, unsigned long size, mtrr_type typ
 
         /*
          * HACK!
-         * We use this same function to initialize the mtrrs on boot.
-         * The state of the boot cpu's mtrrs has been saved, and we want
-         * to replicate across all the APs.
-         * If we're doing that @reg is set to something special...
+         *
+         * We use this same function to initialize the mtrrs during boot,
+         * resume, runtime cpu online and on an explicit request to set a
+         * specific MTRR.
+         *
+         * During boot or suspend, the state of the boot cpu's mtrrs has been
+         * saved, and we want to replicate that across all the cpus that come
+         * online (either at the end of boot or resume or during a runtime cpu
+         * online). If we're doing that, @reg is set to something special and on
+         * this cpu we still do mtrr_if->set_all(). During boot/resume, this
+         * is unnecessary if at this point we are still on the cpu that started
+         * the boot/resume sequence. But there is no guarantee that we are still
+         * on the same cpu. So we do mtrr_if->set_all() on this cpu aswell to be
+         * sure that we are in sync with everyone else.
          */
         if (reg != ~0U)
                 mtrr_if->set(reg, base, size, type);
-        else if (!mtrr_aps_delayed_init)
+        else
                 mtrr_if->set_all();
 
         /* Wait for the others */
@@ -630,7 +641,7 @@ struct mtrr_value {
 
 static struct mtrr_value mtrr_value[MTRR_MAX_VAR_RANGES];
 
-static int mtrr_save(struct sys_device *sysdev, pm_message_t state)
+static int mtrr_save(void)
 {
         int i;
 
@@ -642,7 +653,7 @@ static int mtrr_save(struct sys_device *sysdev, pm_message_t state)
         return 0;
 }
 
-static int mtrr_restore(struct sys_device *sysdev)
+static void mtrr_restore(void)
 {
         int i;
 
@@ -653,12 +664,11 @@ static int mtrr_restore(struct sys_device *sysdev)
                                     mtrr_value[i].ltype);
                 }
         }
-        return 0;
 }
 
 
 
-static struct sysdev_driver mtrr_sysdev_driver = {
+static struct syscore_ops mtrr_syscore_ops = {
         .suspend        = mtrr_save,
         .resume         = mtrr_restore,
 };
@@ -793,13 +803,21 @@ void set_mtrr_aps_delayed_init(void)
 }
 
 /*
- * MTRR initialization for all AP's
+ * Delayed MTRR initialization for all AP's
  */
 void mtrr_aps_init(void)
 {
         if (!use_intel())
                 return;
 
+        /*
+         * Check if someone has requested the delay of AP MTRR initialization,
+         * by doing set_mtrr_aps_delayed_init(), prior to this point. If not,
+         * then we are done.
+         */
+        if (!mtrr_aps_delayed_init)
+                return;
+
         set_mtrr(~0U, 0, 0, 0);
         mtrr_aps_delayed_init = false;
 }
@@ -831,7 +849,7 @@ static int __init mtrr_init_finialize(void)
          * TBD: is there any system with such CPU which supports
          * suspend/resume? If no, we should remove the code.
          */
-        sysdev_driver_register(&cpu_sysdev_class, &mtrr_sysdev_driver);
+        register_syscore_ops(&mtrr_syscore_ops);
 
         return 0;
 }