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>

1 files changed, 101 insertions, 0 deletions

diff --git a/arch/powerpc/platforms/pseries/dlpar.c b/arch/powerpc/platforms/pseries/dlpar.c
index fe8d4b3c50cd..642e1b2e5c42 100644
--- 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);