[IA64] support for cpu0 removal
here is the BSP removal support for IA64. Its pretty much the same thing that
was released a while back, but has your feedback incorporated.
- Removed CONFIG_BSP_REMOVE_WORKAROUND and associated cmdline param
- Fixed compile issue with sn2/zx1 due to a undefined fix_b0_for_bsp
- some formatting nits (whitespace etc)
This has been tested on tiger and long back by alex on hp systems as well.
Signed-off-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
diff --git a/arch/ia64/kernel/smpboot.c b/arch/ia64/kernel/smpboot.c
index 8f44e7d..e9d37bf 100644
--- a/arch/ia64/kernel/smpboot.c
+++ b/arch/ia64/kernel/smpboot.c
@@ -70,6 +70,12 @@
#endif
#ifdef CONFIG_HOTPLUG_CPU
+#ifdef CONFIG_PERMIT_BSP_REMOVE
+#define bsp_remove_ok 1
+#else
+#define bsp_remove_ok 0
+#endif
+
/*
* Store all idle threads, this can be reused instead of creating
* a new thread. Also avoids complicated thread destroy functionality
@@ -104,7 +110,7 @@
/*
* ITC synchronization related stuff:
*/
-#define MASTER 0
+#define MASTER (0)
#define SLAVE (SMP_CACHE_BYTES/8)
#define NUM_ROUNDS 64 /* magic value */
@@ -151,6 +157,27 @@
unsigned char smp_int_redirect; /* are INT and IPI redirectable by the chipset? */
+#ifdef CONFIG_FORCE_CPEI_RETARGET
+#define CPEI_OVERRIDE_DEFAULT (1)
+#else
+#define CPEI_OVERRIDE_DEFAULT (0)
+#endif
+
+unsigned int force_cpei_retarget = CPEI_OVERRIDE_DEFAULT;
+
+static int __init
+cmdl_force_cpei(char *str)
+{
+ int value=0;
+
+ get_option (&str, &value);
+ force_cpei_retarget = value;
+
+ return 1;
+}
+
+__setup("force_cpei=", cmdl_force_cpei);
+
static int __init
nointroute (char *str)
{
@@ -161,6 +188,27 @@
__setup("nointroute", nointroute);
+static void fix_b0_for_bsp(void)
+{
+#ifdef CONFIG_HOTPLUG_CPU
+ int cpuid;
+ static int fix_bsp_b0 = 1;
+
+ cpuid = smp_processor_id();
+
+ /*
+ * Cache the b0 value on the first AP that comes up
+ */
+ if (!(fix_bsp_b0 && cpuid))
+ return;
+
+ sal_boot_rendez_state[0].br[0] = sal_boot_rendez_state[cpuid].br[0];
+ printk ("Fixed BSP b0 value from CPU %d\n", cpuid);
+
+ fix_bsp_b0 = 0;
+#endif
+}
+
void
sync_master (void *arg)
{
@@ -327,8 +375,9 @@
static void __devinit
smp_callin (void)
{
- int cpuid, phys_id;
+ int cpuid, phys_id, itc_master;
extern void ia64_init_itm(void);
+ extern volatile int time_keeper_id;
#ifdef CONFIG_PERFMON
extern void pfm_init_percpu(void);
@@ -336,6 +385,7 @@
cpuid = smp_processor_id();
phys_id = hard_smp_processor_id();
+ itc_master = time_keeper_id;
if (cpu_online(cpuid)) {
printk(KERN_ERR "huh, phys CPU#0x%x, CPU#0x%x already present??\n",
@@ -343,6 +393,8 @@
BUG();
}
+ fix_b0_for_bsp();
+
lock_ipi_calllock();
cpu_set(cpuid, cpu_online_map);
unlock_ipi_calllock();
@@ -365,8 +417,8 @@
* calls spin_unlock_bh(), which calls spin_unlock_bh(), which calls
* local_bh_enable(), which bugs out if irqs are not enabled...
*/
- Dprintk("Going to syncup ITC with BP.\n");
- ia64_sync_itc(0);
+ Dprintk("Going to syncup ITC with ITC Master.\n");
+ ia64_sync_itc(itc_master);
}
/*
@@ -638,6 +690,47 @@
}
extern void fixup_irqs(void);
+
+int migrate_platform_irqs(unsigned int cpu)
+{
+ int new_cpei_cpu;
+ irq_desc_t *desc = NULL;
+ cpumask_t mask;
+ int retval = 0;
+
+ /*
+ * dont permit CPEI target to removed.
+ */
+ if (cpe_vector > 0 && is_cpu_cpei_target(cpu)) {
+ printk ("CPU (%d) is CPEI Target\n", cpu);
+ if (can_cpei_retarget()) {
+ /*
+ * Now re-target the CPEI to a different processor
+ */
+ new_cpei_cpu = any_online_cpu(cpu_online_map);
+ mask = cpumask_of_cpu(new_cpei_cpu);
+ set_cpei_target_cpu(new_cpei_cpu);
+ desc = irq_descp(ia64_cpe_irq);
+ /*
+ * Switch for now, immediatly, we need to do fake intr
+ * as other interrupts, but need to study CPEI behaviour with
+ * polling before making changes.
+ */
+ if (desc) {
+ desc->handler->disable(ia64_cpe_irq);
+ desc->handler->set_affinity(ia64_cpe_irq, mask);
+ desc->handler->enable(ia64_cpe_irq);
+ printk ("Re-targetting CPEI to cpu %d\n", new_cpei_cpu);
+ }
+ }
+ if (!desc) {
+ printk ("Unable to retarget CPEI, offline cpu [%d] failed\n", cpu);
+ retval = -EBUSY;
+ }
+ }
+ return retval;
+}
+
/* must be called with cpucontrol mutex held */
int __cpu_disable(void)
{
@@ -646,8 +739,17 @@
/*
* dont permit boot processor for now
*/
- if (cpu == 0)
- return -EBUSY;
+ if (cpu == 0 && !bsp_remove_ok) {
+ printk ("Your platform does not support removal of BSP\n");
+ return (-EBUSY);
+ }
+
+ cpu_clear(cpu, cpu_online_map);
+
+ if (migrate_platform_irqs(cpu)) {
+ cpu_set(cpu, cpu_online_map);
+ return (-EBUSY);
+ }
remove_siblinginfo(cpu);
cpu_clear(cpu, cpu_online_map);