Use the pSeries_reconfig notifier API to handle processor addition and
removal on pSeries LPAR. This is the "right" way to do it, as opposed
to setting cpu_present_map = cpu_possible_map at boot (this is fixed
in a following patch).
Signed-off-by: Nathan Lynch <[EMAIL PROTECTED]>
Signed-off-by: Paul Mackerras <[EMAIL PROTECTED]>
arch/ppc64/kernel/pSeries_smp.c | 126 ++++++++++++++++++++
1 files changed, 126 insertions(+)
Index: linux-2.6.11-bk10/arch/ppc64/kernel/pSeries_smp.c
===================================================================
--- linux-2.6.11-bk10.orig/arch/ppc64/kernel/pSeries_smp.c 2005-03-14
21:28:14.000000000 +0000
+++ linux-2.6.11-bk10/arch/ppc64/kernel/pSeries_smp.c 2005-03-14
22:29:53.000000000 +0000
@@ -44,6 +44,7 @@
#include <asm/system.h>
#include <asm/rtas.h>
#include <asm/plpar_wrappers.h>
+#include <asm/pSeries_reconfig.h>
#include "mpic.h"
@@ -213,6 +214,127 @@ static inline int __devinit smp_startup_
}
return 1;
}
+
+/*
+ * Update cpu_present_map and paca(s) for a new cpu node. The wrinkle
+ * here is that a cpu device node may represent up to two logical cpus
+ * in the SMT case. We must honor the assumption in other code that
+ * the logical ids for sibling SMT threads x and y are adjacent, such
+ * that x^1 == y and y^1 == x.
+ */
+static int pSeries_add_processor(struct device_node *np)
+{
+ unsigned int cpu;
+ cpumask_t candidate_map, tmp = CPU_MASK_NONE;
+ int err = -ENOSPC, len, nthreads, i;
+ u32 *intserv;
+
+ intserv = (u32 *)get_property(np, "ibm,ppc-interrupt-server#s", &len);
+ if (!intserv)
+ return 0;
+
+ nthreads = len / sizeof(u32);
+ for (i = 0; i < nthreads; i++)
+ cpu_set(i, tmp);
+
+ lock_cpu_hotplug();
+
+ BUG_ON(!cpus_subset(cpu_present_map, cpu_possible_map));
+
+ /* Get a bitmap of unoccupied slots. */
+ cpus_xor(candidate_map, cpu_possible_map, cpu_present_map);
+ if (cpus_empty(candidate_map)) {
+ /* If we get here, it most likely means that NR_CPUS is
+ * less than the partition's max processors setting.
+ */
+ printk(KERN_ERR "Cannot add cpu %s; this system configuration"
+ " supports %d logical cpus.\n", np->full_name,
+ cpus_weight(cpu_possible_map));
+ goto out_unlock;
+ }
+
+ while (!cpus_empty(tmp))
+ if (cpus_subset(tmp, candidate_map))
+ /* Found a range where we can insert the new cpu(s) */
+ break;
+ else
+ cpus_shift_left(tmp, tmp, nthreads);
+
+ if (cpus_empty(tmp)) {
+ printk(KERN_ERR "Unable to find space in cpu_present_map for"
+ " processor %s with %d thread(s)\n", np->name,
+ nthreads);
+ goto out_unlock;
+ }
+
+ for_each_cpu_mask(cpu, tmp) {
+ BUG_ON(cpu_isset(cpu, cpu_present_map));
+ cpu_set(cpu, cpu_present_map);
+ set_hard_smp_processor_id(cpu, *intserv++);
+ }
+ err = 0;
+out_unlock:
+ unlock_cpu_hotplug();
+ return err;
+}
+
+/*
+ * Update the present map for a cpu node which is going away, and set
+ * the hard id in the paca(s) to -1 to be consistent with boot time
+ * convention for non-present cpus.
+ */
+static void pSeries_remove_processor(struct device_node *np)
+{
+ unsigned int cpu;
+ int len, nthreads, i;
+ u32 *intserv;
+
+ intserv = (u32 *)get_property(np, "ibm,ppc-interrupt-server#s", &len);
+ if (!intserv)
+ return;
+
+ nthreads = len / sizeof(u32);
+
+ lock_cpu_hotplug();
+ for (i = 0; i < nthreads; i++) {
+ for_each_present_cpu(cpu) {
+ if (get_hard_smp_processor_id(cpu) != intserv[i])
+ continue;
+ BUG_ON(cpu_online(cpu));
+ cpu_clear(cpu, cpu_present_map);
+ set_hard_smp_processor_id(cpu, -1);
+ break;
+ }
+ if (cpu == NR_CPUS)
+ printk(KERN_WARNING "Could not find cpu to remove "
+ "with physical id 0x%x\n", intserv[i]);
+ }
+ unlock_cpu_hotplug();
+}
+
+static int pSeries_smp_notifier(struct notifier_block *nb, unsigned long
action, void *node)
+{
+ int err = NOTIFY_OK;
+
+ switch (action) {
+ case PSERIES_RECONFIG_ADD:
+ if (pSeries_add_processor(node))
+ err = NOTIFY_BAD;
+ break;
+ case PSERIES_RECONFIG_REMOVE:
+ pSeries_remove_processor(node);
+ break;
+ default:
+ err = NOTIFY_DONE;
+ break;
+ }
+ return err;
+}
+
+static struct notifier_block pSeries_smp_nb = {
+ .notifier_call = pSeries_smp_notifier,
+};
+
#else /* ... CONFIG_HOTPLUG_CPU */
static inline int __devinit smp_startup_cpu(unsigned int lcpu)
{
@@ -336,6 +458,10 @@ void __init smp_init_pSeries(void)
#ifdef CONFIG_HOTPLUG_CPU
smp_ops->cpu_disable = pSeries_cpu_disable;
smp_ops->cpu_die = pSeries_cpu_die;
+
+ /* Processors can be added/removed only on LPAR */
+ if (systemcfg->platform == PLATFORM_PSERIES_LPAR)
+ pSeries_reconfig_notifier_register(&pSeries_smp_nb);
#endif
/* Start secondary threads on SMT systems; primary threads
-
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