Merge branch 'core-smp-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull core SMP updates from Ingo Molnar:
 "Two main change is generic vCPU pinning and physical CPU SMP-call
  support, for Xen to be able to perform certain calls on specific
  physical CPUs - by Juergen Gross"

* 'core-smp-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  smp: Allocate smp_call_on_cpu() workqueue on stack too
  hwmon: Use smp_call_on_cpu() for dell-smm i8k
  dcdbas: Make use of smp_call_on_cpu()
  xen: Add xen_pin_vcpu() to support calling functions on a dedicated pCPU
  smp: Add function to execute a function synchronously on a CPU
  virt, sched: Add generic vCPU pinning support
  xen: Sync xen header

2 files changed, 46 insertions, 41 deletions

diff --git a/drivers/firmware/dcdbas.c b/drivers/firmware/dcdbas.c
index 829eec8959f2..2fe1a130189f 100644
--- a/drivers/firmware/dcdbas.c
+++ b/drivers/firmware/dcdbas.c
@@ -23,6 +23,7 @@
 #include <linux/platform_device.h>
 #include <linux/dma-mapping.h>
 #include <linux/errno.h>
+#include <linux/cpu.h>
 #include <linux/gfp.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
@@ -238,33 +239,14 @@ static ssize_t host_control_on_shutdown_store(struct device *dev,
         return count;
 }
 
-/**
- * dcdbas_smi_request: generate SMI request
- *
- * Called with smi_data_lock.
- */
-int dcdbas_smi_request(struct smi_cmd *smi_cmd)
+static int raise_smi(void *par)
 {
-        cpumask_var_t old_mask;
-        int ret = 0;
-
-        if (smi_cmd->magic != SMI_CMD_MAGIC) {
-                dev_info(&dcdbas_pdev->dev, "%s: invalid magic value\n",
-                         __func__);
-                return -EBADR;
-        }
+        struct smi_cmd *smi_cmd = par;
 
-        /* SMI requires CPU 0 */
-        if (!alloc_cpumask_var(&old_mask, GFP_KERNEL))
-                return -ENOMEM;
-
-        cpumask_copy(old_mask, &current->cpus_allowed);
-        set_cpus_allowed_ptr(current, cpumask_of(0));
         if (smp_processor_id() != 0) {
                 dev_dbg(&dcdbas_pdev->dev, "%s: failed to get CPU 0\n",
                         __func__);
-                ret = -EBUSY;
-                goto out;
+                return -EBUSY;
         }
 
         /* generate SMI */
@@ -280,9 +262,28 @@ int dcdbas_smi_request(struct smi_cmd *smi_cmd)
                 : "memory"
         );
 
-out:
-        set_cpus_allowed_ptr(current, old_mask);
-        free_cpumask_var(old_mask);
+        return 0;
+}
+/**
+ * dcdbas_smi_request: generate SMI request
+ *
+ * Called with smi_data_lock.
+ */
+int dcdbas_smi_request(struct smi_cmd *smi_cmd)
+{
+        int ret;
+
+        if (smi_cmd->magic != SMI_CMD_MAGIC) {
+                dev_info(&dcdbas_pdev->dev, "%s: invalid magic value\n",
+                         __func__);
+                return -EBADR;
+        }
+
+        /* SMI requires CPU 0 */
+        get_online_cpus();
+        ret = smp_call_on_cpu(0, raise_smi, smi_cmd, true);
+        put_online_cpus();
+
         return ret;
 }
 
diff --git a/drivers/hwmon/dell-smm-hwmon.c b/drivers/hwmon/dell-smm-hwmon.c
index acf9c0361d9f..34704b0451b4 100644
--- a/drivers/hwmon/dell-smm-hwmon.c
+++ b/drivers/hwmon/dell-smm-hwmon.c
@@ -21,6 +21,7 @@
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
+#include <linux/cpu.h>
 #include <linux/delay.h>
 #include <linux/module.h>
 #include <linux/types.h>
@@ -36,6 +37,7 @@
 #include <linux/io.h>
 #include <linux/sched.h>
 #include <linux/ctype.h>
+#include <linux/smp.h>
 
 #include <linux/i8k.h>
 
@@ -134,11 +136,11 @@ static inline const char *i8k_get_dmi_data(int field)
 /*
  * Call the System Management Mode BIOS. Code provided by Jonathan Buzzard.
  */
-static int i8k_smm(struct smm_regs *regs)
+static int i8k_smm_func(void *par)
 {
         int rc;
+        struct smm_regs *regs = par;
         int eax = regs->eax;
-        cpumask_var_t old_mask;
 
 #ifdef DEBUG
         int ebx = regs->ebx;
@@ -149,16 +151,8 @@ static int i8k_smm(struct smm_regs *regs)
 #endif
 
         /* SMM requires CPU 0 */
-        if (!alloc_cpumask_var(&old_mask, GFP_KERNEL))
-                return -ENOMEM;
-        cpumask_copy(old_mask, &current->cpus_allowed);
-        rc = set_cpus_allowed_ptr(current, cpumask_of(0));
-        if (rc)
-                goto out;
-        if (smp_processor_id() != 0) {
-                rc = -EBUSY;
-                goto out;
-        }
+        if (smp_processor_id() != 0)
+                return -EBUSY;
 
 #if defined(CONFIG_X86_64)
         asm volatile("pushq %%rax\n\t"
@@ -216,10 +210,6 @@ static int i8k_smm(struct smm_regs *regs)
         if (rc != 0 || (regs->eax & 0xffff) == 0xffff || regs->eax == eax)
                 rc = -EINVAL;
 
-out:
-        set_cpus_allowed_ptr(current, old_mask);
-        free_cpumask_var(old_mask);
-
 #ifdef DEBUG
         rettime = ktime_get();
         delta = ktime_sub(rettime, calltime);
@@ -232,6 +222,20 @@ out:
 }
 
 /*
+ * Call the System Management Mode BIOS.
+ */
+static int i8k_smm(struct smm_regs *regs)
+{
+        int ret;
+
+        get_online_cpus();
+        ret = smp_call_on_cpu(0, i8k_smm_func, regs, true);
+        put_online_cpus();
+
+        return ret;
+}
+
+/*
  * Read the fan status.
  */
 static int i8k_get_fan_status(int fan)