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-rw-r--r--arch/x86_64/kernel/smp.c63
-rw-r--r--arch/x86_64/kernel/smpboot.c21
-rw-r--r--include/asm-x86_64/smp.h3
3 files changed, 78 insertions, 9 deletions
diff --git a/arch/x86_64/kernel/smp.c b/arch/x86_64/kernel/smp.c
index 6ee74db5230..e5958220d6b 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 6d23354443c..6e4807d64d4 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)
diff --git a/include/asm-x86_64/smp.h b/include/asm-x86_64/smp.h
index 18ac762e1ab..de8b57b2b62 100644
--- a/include/asm-x86_64/smp.h
+++ b/include/asm-x86_64/smp.h
@@ -49,6 +49,9 @@ extern int smp_num_siblings;
extern void smp_send_reschedule(int cpu);
extern void zap_low_mappings(void);
void smp_stop_cpu(void);
+extern int smp_call_function_single(int cpuid, void (*func) (void *info),
+ void *info, int retry, int wait);
+
extern cpumask_t cpu_sibling_map[NR_CPUS];
extern cpumask_t cpu_core_map[NR_CPUS];
extern u8 phys_proc_id[NR_CPUS];