MIPS: Add arch generic CPU hotplug
Each platform has to add support for CPU hotplugging itself by providing
suitable definitions for the cpu_disable and cpu_die of the smp_ops
methods and setting SYS_SUPPORTS_HOTPLUG_CPU. A platform should only set
SYS_SUPPORTS_HOTPLUG_CPU once all it's smp_ops definitions have the
necessary changes. This patch contains the changes to the dummy smp_ops
definition for uni-processor systems.
Parts of the code contributed by Cavium Inc.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/kernel/smp.c b/arch/mips/kernel/smp.c
index 58f4679..bc7d9b0 100644
--- a/arch/mips/kernel/smp.c
+++ b/arch/mips/kernel/smp.c
@@ -45,7 +45,7 @@
#include <asm/mipsmtregs.h>
#endif /* CONFIG_MIPS_MT_SMTC */
-static volatile cpumask_t cpu_callin_map; /* Bitmask of started secondaries */
+volatile cpumask_t cpu_callin_map; /* Bitmask of started secondaries */
int __cpu_number_map[NR_CPUS]; /* Map physical to logical */
int __cpu_logical_map[NR_CPUS]; /* Map logical to physical */
@@ -201,6 +201,8 @@
* and keep control until "cpu_online(cpu)" is set. Note: cpu is
* physical, not logical.
*/
+static struct task_struct *cpu_idle_thread[NR_CPUS];
+
int __cpuinit __cpu_up(unsigned int cpu)
{
struct task_struct *idle;
@@ -210,9 +212,16 @@
* The following code is purely to make sure
* Linux can schedule processes on this slave.
*/
- idle = fork_idle(cpu);
- if (IS_ERR(idle))
- panic(KERN_ERR "Fork failed for CPU %d", cpu);
+ if (!cpu_idle_thread[cpu]) {
+ idle = fork_idle(cpu);
+ cpu_idle_thread[cpu] = idle;
+
+ if (IS_ERR(idle))
+ panic(KERN_ERR "Fork failed for CPU %d", cpu);
+ } else {
+ idle = cpu_idle_thread[cpu];
+ init_idle(idle, cpu);
+ }
mp_ops->boot_secondary(cpu, idle);