pseries/pseries: Add code to online/offline CPUs of a DLPAR node

Currently the cpu-allocation/deallocation on pSeries is a
two step process from the Userspace.

- Set the indicators and update the device tree by writing to the sysfs
  tunable "probe" during allocation and "release" during deallocation.
- Online / Offline the CPUs of the allocated/would_be_deallocated node by
  writing to the sysfs tunable "online".

This patch adds kernel code to online/offline the CPUs soon_after/just_before
they have been allocated/would_be_deallocated. This way, the userspace tool
that performs DLPAR operations would only have to deal with one set of sysfs
tunables namely "probe" and release".

Signed-off-by: Gautham R Shenoy <ego@in.ibm.com>
Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com>
Acked-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

diff --git a/arch/powerpc/platforms/pseries/dlpar.c b/arch/powerpc/platforms/pseries/dlpar.c
index fe8d4b3..642e1b2 100644 (file)
--- a/arch/powerpc/platforms/pseries/dlpar.c
+++ b/arch/powerpc/platforms/pseries/dlpar.c
@@ -16,6 +16,7 @@
 #include <linux/proc_fs.h>
 #include <linux/spinlock.h>
 #include <linux/cpu.h>
+#include "offline_states.h"
 
 #include <asm/prom.h>
 #include <asm/machdep.h>
@@ -287,6 +288,98 @@ int dlpar_detach_node(struct device_node *dn)
        return 0;
 }
 
+int online_node_cpus(struct device_node *dn)
+{
+       int rc = 0;
+       unsigned int cpu;
+       int len, nthreads, i;
+       const u32 *intserv;
+
+       intserv = of_get_property(dn, "ibm,ppc-interrupt-server#s", &len);
+       if (!intserv)
+               return -EINVAL;
+
+       nthreads = len / sizeof(u32);
+
+       cpu_maps_update_begin();
+       for (i = 0; i < nthreads; i++) {
+               for_each_present_cpu(cpu) {
+                       if (get_hard_smp_processor_id(cpu) != intserv[i])
+                               continue;
+                       BUG_ON(get_cpu_current_state(cpu)
+                                       != CPU_STATE_OFFLINE);
+                       cpu_maps_update_done();
+                       rc = cpu_up(cpu);
+                       if (rc)
+                               goto out;
+                       cpu_maps_update_begin();
+
+                       break;
+               }
+               if (cpu == num_possible_cpus())
+                       printk(KERN_WARNING "Could not find cpu to online "
+                              "with physical id 0x%x\n", intserv[i]);
+       }
+       cpu_maps_update_done();
+
+out:
+       return rc;
+
+}
+
+int offline_node_cpus(struct device_node *dn)
+{
+       int rc = 0;
+       unsigned int cpu;
+       int len, nthreads, i;
+       const u32 *intserv;
+
+       intserv = of_get_property(dn, "ibm,ppc-interrupt-server#s", &len);
+       if (!intserv)
+               return -EINVAL;
+
+       nthreads = len / sizeof(u32);
+
+       cpu_maps_update_begin();
+       for (i = 0; i < nthreads; i++) {
+               for_each_present_cpu(cpu) {
+                       if (get_hard_smp_processor_id(cpu) != intserv[i])
+                               continue;
+
+                       if (get_cpu_current_state(cpu) == CPU_STATE_OFFLINE)
+                               break;
+
+                       if (get_cpu_current_state(cpu) == CPU_STATE_ONLINE) {
+                               cpu_maps_update_done();
+                               rc = cpu_down(cpu);
+                               if (rc)
+                                       goto out;
+                               cpu_maps_update_begin();
+                               break;
+
+                       }
+
+                       /*
+                        * The cpu is in CPU_STATE_INACTIVE.
+                        * Upgrade it's state to CPU_STATE_OFFLINE.
+                        */
+                       set_preferred_offline_state(cpu, CPU_STATE_OFFLINE);
+                       BUG_ON(plpar_hcall_norets(H_PROD, intserv[i])
+                                                               != H_SUCCESS);
+                       __cpu_die(cpu);
+                       break;
+               }
+               if (cpu == num_possible_cpus())
+                       printk(KERN_WARNING "Could not find cpu to offline "
+                              "with physical id 0x%x\n", intserv[i]);
+       }
+       cpu_maps_update_done();
+
+out:
+       return rc;
+
+}
+
 #define DR_ENTITY_SENSE                9003
 #define DR_ENTITY_PRESENT      1
 #define DR_ENTITY_UNUSABLE     2
@@ -385,6 +478,8 @@ static ssize_t dlpar_cpu_probe(const char *buf, size_t count)
                dlpar_free_cc_nodes(dn);
        }
 
+       rc = online_node_cpus(dn);
+
        return rc ? rc : count;
 }
 
@@ -404,6 +499,12 @@ static ssize_t dlpar_cpu_release(const char *buf, size_t count)
                return -EINVAL;
        }
 
+       rc = offline_node_cpus(dn);
+       if (rc) {
+               of_node_put(dn);
+               return -EINVAL;
+       }
+
        rc = dlpar_release_drc(*drc_index);
        if (rc) {
                of_node_put(dn);