2 files changed, 75 insertions, 9 deletions

diff --git a/arch/x86_64/kernel/smp.c b/arch/x86_64/kernel/smp.c
index 6ee74db52303..e5958220d6b8 100644
--- a/arch/x86_64/kernel/smp.c
+++ b/arch/x86_64/kernel/smp.c
@@ -293,6 +293,69 @@ void unlock_ipi_call_lock(void)
 }
 
 /*
+ * this function sends a 'generic call function' IPI to one other CPU
+ * in the system.
+ */
+static void __smp_call_function_single (int cpu, void (*func) (void *info), void *info,
+                                int nonatomic, int wait)
+{
+        struct call_data_struct data;
+        int cpus = 1;
+
+        data.func = func;
+        data.info = info;
+        atomic_set(&data.started, 0);
+        data.wait = wait;
+        if (wait)
+                atomic_set(&data.finished, 0);
+
+        call_data = &data;
+        wmb();
+        /* Send a message to all other CPUs and wait for them to respond */
+        send_IPI_mask(cpumask_of_cpu(cpu), CALL_FUNCTION_VECTOR);
+
+        /* Wait for response */
+        while (atomic_read(&data.started) != cpus)
+                cpu_relax();
+
+        if (!wait)
+                return;
+
+        while (atomic_read(&data.finished) != cpus)
+                cpu_relax();
+}
+
+/*
+ * smp_call_function_single - Run a function on another CPU
+ * @func: The function to run. This must be fast and non-blocking.
+ * @info: An arbitrary pointer to pass to the function.
+ * @nonatomic: Currently unused.
+ * @wait: If true, wait until function has completed on other CPUs.
+ *
+ * Retrurns 0 on success, else a negative status code.
+ *
+ * Does not return until the remote CPU is nearly ready to execute <func>
+ * or is or has executed.
+ */
+
+int smp_call_function_single (int cpu, void (*func) (void *info), void *info,
+        int nonatomic, int wait)
+{
+        /* prevent preemption and reschedule on another processor */
+        int me = get_cpu();
+        if (cpu == me) {
+                WARN_ON(1);
+                put_cpu();
+                return -EBUSY;
+        }
+        spin_lock_bh(&call_lock);
+        __smp_call_function_single(cpu, func, info, nonatomic, wait);
+        spin_unlock_bh(&call_lock);
+        put_cpu();
+        return 0;
+}
+
+/*
  * this function sends a 'generic call function' IPI to all other CPUs
  * in the system.
  */
diff --git a/arch/x86_64/kernel/smpboot.c b/arch/x86_64/kernel/smpboot.c
index 6d23354443c0..6e4807d64d46 100644
--- a/arch/x86_64/kernel/smpboot.c
+++ b/arch/x86_64/kernel/smpboot.c
@@ -211,9 +211,6 @@ static __cpuinit void sync_master(void *arg)
 {
         unsigned long flags, i;
 
-        if (smp_processor_id() != 0)
-                return;
-
         go[MASTER] = 0;
 
         local_irq_save(flags);
@@ -262,7 +259,7 @@ get_delta(long *rt, long *master)
         return tcenter - best_tm;
 }
 
-static __cpuinit void sync_tsc(void)
+static __cpuinit void sync_tsc(unsigned int master)
 {
         int i, done = 0;
         long delta, adj, adjust_latency = 0;
@@ -276,9 +273,17 @@ static __cpuinit void sync_tsc(void)
         } t[NUM_ROUNDS] __cpuinitdata;
 #endif
 
+        printk(KERN_INFO "CPU %d: Syncing TSC to CPU %u.\n",
+                smp_processor_id(), master);
+
         go[MASTER] = 1;
 
-        smp_call_function(sync_master, NULL, 1, 0);
+        /* It is dangerous to broadcast IPI as cpus are coming up,
+         * as they may not be ready to accept them.  So since
+         * we only need to send the ipi to the boot cpu direct
+         * the message, and avoid the race.
+         */
+        smp_call_function_single(master, sync_master, NULL, 1, 0);
 
         while (go[MASTER])      /* wait for master to be ready */
                 no_cpu_relax();
@@ -322,16 +327,14 @@ static __cpuinit void sync_tsc(void)
         printk(KERN_INFO
                "CPU %d: synchronized TSC with CPU %u (last diff %ld cycles, "
                "maxerr %lu cycles)\n",
-               smp_processor_id(), boot_cpu_id, delta, rt);
+               smp_processor_id(), master, delta, rt);
 }
 
 static void __cpuinit tsc_sync_wait(void)
 {
         if (notscsync || !cpu_has_tsc)
                 return;
-        printk(KERN_INFO "CPU %d: Syncing TSC to CPU %u.\n", smp_processor_id(),
-                        boot_cpu_id);
-        sync_tsc();
+        sync_tsc(boot_cpu_id);
 }
 
 static __init int notscsync_setup(char *s)