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Diffstat (limited to 'arch/powerpc/kernel/smp.c')
-rw-r--r--arch/powerpc/kernel/smp.c153
1 files changed, 97 insertions, 56 deletions
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index 98136050917..cbdbb14be4b 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -57,6 +57,25 @@
#define DBG(fmt...)
#endif
+
+/* Store all idle threads, this can be reused instead of creating
+* a new thread. Also avoids complicated thread destroy functionality
+* for idle threads.
+*/
+#ifdef CONFIG_HOTPLUG_CPU
+/*
+ * Needed only for CONFIG_HOTPLUG_CPU because __cpuinitdata is
+ * removed after init for !CONFIG_HOTPLUG_CPU.
+ */
+static DEFINE_PER_CPU(struct task_struct *, idle_thread_array);
+#define get_idle_for_cpu(x) (per_cpu(idle_thread_array, x))
+#define set_idle_for_cpu(x, p) (per_cpu(idle_thread_array, x) = (p))
+#else
+static struct task_struct *idle_thread_array[NR_CPUS] __cpuinitdata ;
+#define get_idle_for_cpu(x) (idle_thread_array[(x)])
+#define set_idle_for_cpu(x, p) (idle_thread_array[(x)] = (p))
+#endif
+
struct thread_info *secondary_ti;
DEFINE_PER_CPU(cpumask_var_t, cpu_sibling_map);
@@ -238,23 +257,6 @@ static void __devinit smp_store_cpu_info(int id)
per_cpu(cpu_pvr, id) = mfspr(SPRN_PVR);
}
-static void __init smp_create_idle(unsigned int cpu)
-{
- struct task_struct *p;
-
- /* create a process for the processor */
- p = fork_idle(cpu);
- if (IS_ERR(p))
- panic("failed fork for CPU %u: %li", cpu, PTR_ERR(p));
-#ifdef CONFIG_PPC64
- paca[cpu].__current = p;
- paca[cpu].kstack = (unsigned long) task_thread_info(p)
- + THREAD_SIZE - STACK_FRAME_OVERHEAD;
-#endif
- current_set[cpu] = task_thread_info(p);
- task_thread_info(p)->cpu = cpu;
-}
-
void __init smp_prepare_cpus(unsigned int max_cpus)
{
unsigned int cpu;
@@ -288,10 +290,6 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
max_cpus = NR_CPUS;
else
max_cpus = 1;
-
- for_each_possible_cpu(cpu)
- if (cpu != boot_cpuid)
- smp_create_idle(cpu);
}
void __devinit smp_prepare_boot_cpu(void)
@@ -305,7 +303,7 @@ void __devinit smp_prepare_boot_cpu(void)
#ifdef CONFIG_HOTPLUG_CPU
/* State of each CPU during hotplug phases */
-DEFINE_PER_CPU(int, cpu_state) = { 0 };
+static DEFINE_PER_CPU(int, cpu_state) = { 0 };
int generic_cpu_disable(void)
{
@@ -317,30 +315,8 @@ int generic_cpu_disable(void)
set_cpu_online(cpu, false);
#ifdef CONFIG_PPC64
vdso_data->processorCount--;
- fixup_irqs(cpu_online_mask);
-#endif
- return 0;
-}
-
-int generic_cpu_enable(unsigned int cpu)
-{
- /* Do the normal bootup if we haven't
- * already bootstrapped. */
- if (system_state != SYSTEM_RUNNING)
- return -ENOSYS;
-
- /* get the target out of it's holding state */
- per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
- smp_wmb();
-
- while (!cpu_online(cpu))
- cpu_relax();
-
-#ifdef CONFIG_PPC64
- fixup_irqs(cpu_online_mask);
- /* counter the irq disable in fixup_irqs */
- local_irq_enable();
#endif
+ migrate_irqs();
return 0;
}
@@ -362,37 +338,89 @@ void generic_mach_cpu_die(void)
unsigned int cpu;
local_irq_disable();
+ idle_task_exit();
cpu = smp_processor_id();
printk(KERN_DEBUG "CPU%d offline\n", cpu);
__get_cpu_var(cpu_state) = CPU_DEAD;
smp_wmb();
while (__get_cpu_var(cpu_state) != CPU_UP_PREPARE)
cpu_relax();
- set_cpu_online(cpu, true);
- local_irq_enable();
+}
+
+void generic_set_cpu_dead(unsigned int cpu)
+{
+ per_cpu(cpu_state, cpu) = CPU_DEAD;
}
#endif
-static int __devinit cpu_enable(unsigned int cpu)
+struct create_idle {
+ struct work_struct work;
+ struct task_struct *idle;
+ struct completion done;
+ int cpu;
+};
+
+static void __cpuinit do_fork_idle(struct work_struct *work)
{
- if (smp_ops && smp_ops->cpu_enable)
- return smp_ops->cpu_enable(cpu);
+ struct create_idle *c_idle =
+ container_of(work, struct create_idle, work);
+
+ c_idle->idle = fork_idle(c_idle->cpu);
+ complete(&c_idle->done);
+}
+
+static int __cpuinit create_idle(unsigned int cpu)
+{
+ struct thread_info *ti;
+ struct create_idle c_idle = {
+ .cpu = cpu,
+ .done = COMPLETION_INITIALIZER_ONSTACK(c_idle.done),
+ };
+ INIT_WORK_ONSTACK(&c_idle.work, do_fork_idle);
+
+ c_idle.idle = get_idle_for_cpu(cpu);
+
+ /* We can't use kernel_thread since we must avoid to
+ * reschedule the child. We use a workqueue because
+ * we want to fork from a kernel thread, not whatever
+ * userspace process happens to be trying to online us.
+ */
+ if (!c_idle.idle) {
+ schedule_work(&c_idle.work);
+ wait_for_completion(&c_idle.done);
+ } else
+ init_idle(c_idle.idle, cpu);
+ if (IS_ERR(c_idle.idle)) {
+ pr_err("Failed fork for CPU %u: %li", cpu, PTR_ERR(c_idle.idle));
+ return PTR_ERR(c_idle.idle);
+ }
+ ti = task_thread_info(c_idle.idle);
+
+#ifdef CONFIG_PPC64
+ paca[cpu].__current = c_idle.idle;
+ paca[cpu].kstack = (unsigned long)ti + THREAD_SIZE - STACK_FRAME_OVERHEAD;
+#endif
+ ti->cpu = cpu;
+ current_set[cpu] = ti;
- return -ENOSYS;
+ return 0;
}
int __cpuinit __cpu_up(unsigned int cpu)
{
- int c;
+ int rc, c;
secondary_ti = current_set[cpu];
- if (!cpu_enable(cpu))
- return 0;
if (smp_ops == NULL ||
(smp_ops->cpu_bootable && !smp_ops->cpu_bootable(cpu)))
return -EINVAL;
+ /* Make sure we have an idle thread */
+ rc = create_idle(cpu);
+ if (rc)
+ return rc;
+
/* Make sure callin-map entry is 0 (can be leftover a CPU
* hotplug
*/
@@ -502,7 +530,7 @@ static struct device_node *cpu_to_l2cache(int cpu)
}
/* Activate a secondary processor. */
-int __devinit start_secondary(void *unused)
+void __devinit start_secondary(void *unused)
{
unsigned int cpu = smp_processor_id();
struct device_node *l2_cache;
@@ -523,6 +551,10 @@ int __devinit start_secondary(void *unused)
secondary_cpu_time_init();
+#ifdef CONFIG_PPC64
+ if (system_state == SYSTEM_RUNNING)
+ vdso_data->processorCount++;
+#endif
ipi_call_lock();
notify_cpu_starting(cpu);
set_cpu_online(cpu, true);
@@ -558,7 +590,8 @@ int __devinit start_secondary(void *unused)
local_irq_enable();
cpu_idle();
- return 0;
+
+ BUG();
}
int setup_profiling_timer(unsigned int multiplier)
@@ -585,7 +618,11 @@ void __init smp_cpus_done(unsigned int max_cpus)
free_cpumask_var(old_mask);
+ if (smp_ops && smp_ops->bringup_done)
+ smp_ops->bringup_done();
+
dump_numa_cpu_topology();
+
}
int arch_sd_sibling_asym_packing(void)
@@ -660,5 +697,9 @@ void cpu_die(void)
{
if (ppc_md.cpu_die)
ppc_md.cpu_die();
+
+ /* If we return, we re-enter start_secondary */
+ start_secondary_resume();
}
+
#endif