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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-06 01:02:30 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-06 01:02:30 +0000
commit76cb841cb886eef6b3bee341a2266c76578724ad (patch)
treef5892e5ba6cc11949952a6ce4ecbe6d516d6ce58 /arch/powerpc/platforms/pseries/hotplug-cpu.c
parentInitial commit. (diff)
downloadlinux-c109f8d9e922037b3fa45f46d78384d49db8ad76.tar.xz
linux-c109f8d9e922037b3fa45f46d78384d49db8ad76.zip
Adding upstream version 4.19.249.upstream/4.19.249upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/powerpc/platforms/pseries/hotplug-cpu.c')
-rw-r--r--arch/powerpc/platforms/pseries/hotplug-cpu.c975
1 files changed, 975 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/pseries/hotplug-cpu.c b/arch/powerpc/platforms/pseries/hotplug-cpu.c
new file mode 100644
index 000000000..8bfb97d07
--- /dev/null
+++ b/arch/powerpc/platforms/pseries/hotplug-cpu.c
@@ -0,0 +1,975 @@
+/*
+ * pseries CPU Hotplug infrastructure.
+ *
+ * Split out from arch/powerpc/platforms/pseries/setup.c
+ * arch/powerpc/kernel/rtas.c, and arch/powerpc/platforms/pseries/smp.c
+ *
+ * Peter Bergner, IBM March 2001.
+ * Copyright (C) 2001 IBM.
+ * Dave Engebretsen, Peter Bergner, and
+ * Mike Corrigan {engebret|bergner|mikec}@us.ibm.com
+ * Plus various changes from other IBM teams...
+ *
+ * Copyright (C) 2006 Michael Ellerman, IBM Corporation
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#define pr_fmt(fmt) "pseries-hotplug-cpu: " fmt
+
+#include <linux/kernel.h>
+#include <linux/interrupt.h>
+#include <linux/delay.h>
+#include <linux/sched.h> /* for idle_task_exit */
+#include <linux/sched/hotplug.h>
+#include <linux/cpu.h>
+#include <linux/of.h>
+#include <linux/slab.h>
+#include <asm/prom.h>
+#include <asm/rtas.h>
+#include <asm/firmware.h>
+#include <asm/machdep.h>
+#include <asm/vdso_datapage.h>
+#include <asm/xics.h>
+#include <asm/xive.h>
+#include <asm/plpar_wrappers.h>
+#include <asm/topology.h>
+
+#include "pseries.h"
+#include "offline_states.h"
+
+/* This version can't take the spinlock, because it never returns */
+static int rtas_stop_self_token = RTAS_UNKNOWN_SERVICE;
+
+static DEFINE_PER_CPU(enum cpu_state_vals, preferred_offline_state) =
+ CPU_STATE_OFFLINE;
+static DEFINE_PER_CPU(enum cpu_state_vals, current_state) = CPU_STATE_OFFLINE;
+
+static enum cpu_state_vals default_offline_state = CPU_STATE_OFFLINE;
+
+static bool cede_offline_enabled __read_mostly = true;
+
+/*
+ * Enable/disable cede_offline when available.
+ */
+static int __init setup_cede_offline(char *str)
+{
+ return (kstrtobool(str, &cede_offline_enabled) == 0);
+}
+
+__setup("cede_offline=", setup_cede_offline);
+
+enum cpu_state_vals get_cpu_current_state(int cpu)
+{
+ return per_cpu(current_state, cpu);
+}
+
+void set_cpu_current_state(int cpu, enum cpu_state_vals state)
+{
+ per_cpu(current_state, cpu) = state;
+}
+
+enum cpu_state_vals get_preferred_offline_state(int cpu)
+{
+ return per_cpu(preferred_offline_state, cpu);
+}
+
+void set_preferred_offline_state(int cpu, enum cpu_state_vals state)
+{
+ per_cpu(preferred_offline_state, cpu) = state;
+}
+
+void set_default_offline_state(int cpu)
+{
+ per_cpu(preferred_offline_state, cpu) = default_offline_state;
+}
+
+static void rtas_stop_self(void)
+{
+ static struct rtas_args args;
+
+ local_irq_disable();
+
+ BUG_ON(rtas_stop_self_token == RTAS_UNKNOWN_SERVICE);
+
+ rtas_call_unlocked(&args, rtas_stop_self_token, 0, 1, NULL);
+
+ panic("Alas, I survived.\n");
+}
+
+static void pseries_mach_cpu_die(void)
+{
+ unsigned int cpu = smp_processor_id();
+ unsigned int hwcpu = hard_smp_processor_id();
+ u8 cede_latency_hint = 0;
+
+ local_irq_disable();
+ idle_task_exit();
+ if (xive_enabled())
+ xive_teardown_cpu();
+ else
+ xics_teardown_cpu();
+
+ if (get_preferred_offline_state(cpu) == CPU_STATE_INACTIVE) {
+ set_cpu_current_state(cpu, CPU_STATE_INACTIVE);
+ if (ppc_md.suspend_disable_cpu)
+ ppc_md.suspend_disable_cpu();
+
+ cede_latency_hint = 2;
+
+ get_lppaca()->idle = 1;
+ if (!lppaca_shared_proc(get_lppaca()))
+ get_lppaca()->donate_dedicated_cpu = 1;
+
+ while (get_preferred_offline_state(cpu) == CPU_STATE_INACTIVE) {
+ while (!prep_irq_for_idle()) {
+ local_irq_enable();
+ local_irq_disable();
+ }
+
+ extended_cede_processor(cede_latency_hint);
+ }
+
+ local_irq_disable();
+
+ if (!lppaca_shared_proc(get_lppaca()))
+ get_lppaca()->donate_dedicated_cpu = 0;
+ get_lppaca()->idle = 0;
+
+ if (get_preferred_offline_state(cpu) == CPU_STATE_ONLINE) {
+ unregister_slb_shadow(hwcpu);
+
+ hard_irq_disable();
+ /*
+ * Call to start_secondary_resume() will not return.
+ * Kernel stack will be reset and start_secondary()
+ * will be called to continue the online operation.
+ */
+ start_secondary_resume();
+ }
+ }
+
+ /* Requested state is CPU_STATE_OFFLINE at this point */
+ WARN_ON(get_preferred_offline_state(cpu) != CPU_STATE_OFFLINE);
+
+ set_cpu_current_state(cpu, CPU_STATE_OFFLINE);
+ unregister_slb_shadow(hwcpu);
+ rtas_stop_self();
+
+ /* Should never get here... */
+ BUG();
+ for(;;);
+}
+
+static int pseries_cpu_disable(void)
+{
+ int cpu = smp_processor_id();
+
+ set_cpu_online(cpu, false);
+ vdso_data->processorCount--;
+
+ /*fix boot_cpuid here*/
+ if (cpu == boot_cpuid)
+ boot_cpuid = cpumask_any(cpu_online_mask);
+
+ /* FIXME: abstract this to not be platform specific later on */
+ if (xive_enabled())
+ xive_smp_disable_cpu();
+ else
+ xics_migrate_irqs_away();
+ return 0;
+}
+
+/*
+ * pseries_cpu_die: Wait for the cpu to die.
+ * @cpu: logical processor id of the CPU whose death we're awaiting.
+ *
+ * This function is called from the context of the thread which is performing
+ * the cpu-offline. Here we wait for long enough to allow the cpu in question
+ * to self-destroy so that the cpu-offline thread can send the CPU_DEAD
+ * notifications.
+ *
+ * OTOH, pseries_mach_cpu_die() is called by the @cpu when it wants to
+ * self-destruct.
+ */
+static void pseries_cpu_die(unsigned int cpu)
+{
+ int tries;
+ int cpu_status = 1;
+ unsigned int pcpu = get_hard_smp_processor_id(cpu);
+
+ if (get_preferred_offline_state(cpu) == CPU_STATE_INACTIVE) {
+ cpu_status = 1;
+ for (tries = 0; tries < 5000; tries++) {
+ if (get_cpu_current_state(cpu) == CPU_STATE_INACTIVE) {
+ cpu_status = 0;
+ break;
+ }
+ msleep(1);
+ }
+ } else if (get_preferred_offline_state(cpu) == CPU_STATE_OFFLINE) {
+
+ for (tries = 0; tries < 25; tries++) {
+ cpu_status = smp_query_cpu_stopped(pcpu);
+ if (cpu_status == QCSS_STOPPED ||
+ cpu_status == QCSS_HARDWARE_ERROR)
+ break;
+ cpu_relax();
+ }
+ }
+
+ if (cpu_status != 0) {
+ printk("Querying DEAD? cpu %i (%i) shows %i\n",
+ cpu, pcpu, cpu_status);
+ }
+
+ /* Isolation and deallocation are definitely done by
+ * drslot_chrp_cpu. If they were not they would be
+ * done here. Change isolate state to Isolate and
+ * change allocation-state to Unusable.
+ */
+ paca_ptrs[cpu]->cpu_start = 0;
+}
+
+/*
+ * Update cpu_present_mask 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_var_t candidate_mask, tmp;
+ int err = -ENOSPC, len, nthreads, i;
+ const __be32 *intserv;
+
+ intserv = of_get_property(np, "ibm,ppc-interrupt-server#s", &len);
+ if (!intserv)
+ return 0;
+
+ zalloc_cpumask_var(&candidate_mask, GFP_KERNEL);
+ zalloc_cpumask_var(&tmp, GFP_KERNEL);
+
+ nthreads = len / sizeof(u32);
+ for (i = 0; i < nthreads; i++)
+ cpumask_set_cpu(i, tmp);
+
+ cpu_maps_update_begin();
+
+ BUG_ON(!cpumask_subset(cpu_present_mask, cpu_possible_mask));
+
+ /* Get a bitmap of unoccupied slots. */
+ cpumask_xor(candidate_mask, cpu_possible_mask, cpu_present_mask);
+ if (cpumask_empty(candidate_mask)) {
+ /* 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 %pOF; this system configuration"
+ " supports %d logical cpus.\n", np,
+ num_possible_cpus());
+ goto out_unlock;
+ }
+
+ while (!cpumask_empty(tmp))
+ if (cpumask_subset(tmp, candidate_mask))
+ /* Found a range where we can insert the new cpu(s) */
+ break;
+ else
+ cpumask_shift_left(tmp, tmp, nthreads);
+
+ if (cpumask_empty(tmp)) {
+ printk(KERN_ERR "Unable to find space in cpu_present_mask for"
+ " processor %s with %d thread(s)\n", np->name,
+ nthreads);
+ goto out_unlock;
+ }
+
+ for_each_cpu(cpu, tmp) {
+ BUG_ON(cpu_present(cpu));
+ set_cpu_present(cpu, true);
+ set_hard_smp_processor_id(cpu, be32_to_cpu(*intserv++));
+ }
+ err = 0;
+out_unlock:
+ cpu_maps_update_done();
+ free_cpumask_var(candidate_mask);
+ free_cpumask_var(tmp);
+ 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;
+ const __be32 *intserv;
+ u32 thread;
+
+ intserv = of_get_property(np, "ibm,ppc-interrupt-server#s", &len);
+ if (!intserv)
+ return;
+
+ nthreads = len / sizeof(u32);
+
+ cpu_maps_update_begin();
+ for (i = 0; i < nthreads; i++) {
+ thread = be32_to_cpu(intserv[i]);
+ for_each_present_cpu(cpu) {
+ if (get_hard_smp_processor_id(cpu) != thread)
+ continue;
+ BUG_ON(cpu_online(cpu));
+ set_cpu_present(cpu, false);
+ set_hard_smp_processor_id(cpu, -1);
+ update_numa_cpu_lookup_table(cpu, -1);
+ break;
+ }
+ if (cpu >= nr_cpu_ids)
+ printk(KERN_WARNING "Could not find cpu to remove "
+ "with physical id 0x%x\n", thread);
+ }
+ cpu_maps_update_done();
+}
+
+static int dlpar_online_cpu(struct device_node *dn)
+{
+ int rc = 0;
+ unsigned int cpu;
+ int len, nthreads, i;
+ const __be32 *intserv;
+ u32 thread;
+
+ 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++) {
+ thread = be32_to_cpu(intserv[i]);
+ for_each_present_cpu(cpu) {
+ if (get_hard_smp_processor_id(cpu) != thread)
+ continue;
+ BUG_ON(get_cpu_current_state(cpu)
+ != CPU_STATE_OFFLINE);
+ cpu_maps_update_done();
+ timed_topology_update(1);
+ find_and_online_cpu_nid(cpu);
+ rc = device_online(get_cpu_device(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", thread);
+ }
+ cpu_maps_update_done();
+
+out:
+ return rc;
+
+}
+
+static bool dlpar_cpu_exists(struct device_node *parent, u32 drc_index)
+{
+ struct device_node *child = NULL;
+ u32 my_drc_index;
+ bool found;
+ int rc;
+
+ /* Assume cpu doesn't exist */
+ found = false;
+
+ for_each_child_of_node(parent, child) {
+ rc = of_property_read_u32(child, "ibm,my-drc-index",
+ &my_drc_index);
+ if (rc)
+ continue;
+
+ if (my_drc_index == drc_index) {
+ of_node_put(child);
+ found = true;
+ break;
+ }
+ }
+
+ return found;
+}
+
+static bool valid_cpu_drc_index(struct device_node *parent, u32 drc_index)
+{
+ bool found = false;
+ int rc, index;
+
+ index = 0;
+ while (!found) {
+ u32 drc;
+
+ rc = of_property_read_u32_index(parent, "ibm,drc-indexes",
+ index++, &drc);
+ if (rc)
+ break;
+
+ if (drc == drc_index)
+ found = true;
+ }
+
+ return found;
+}
+
+static ssize_t dlpar_cpu_add(u32 drc_index)
+{
+ struct device_node *dn, *parent;
+ int rc, saved_rc;
+
+ pr_debug("Attempting to add CPU, drc index: %x\n", drc_index);
+
+ parent = of_find_node_by_path("/cpus");
+ if (!parent) {
+ pr_warn("Failed to find CPU root node \"/cpus\"\n");
+ return -ENODEV;
+ }
+
+ if (dlpar_cpu_exists(parent, drc_index)) {
+ of_node_put(parent);
+ pr_warn("CPU with drc index %x already exists\n", drc_index);
+ return -EINVAL;
+ }
+
+ if (!valid_cpu_drc_index(parent, drc_index)) {
+ of_node_put(parent);
+ pr_warn("Cannot find CPU (drc index %x) to add.\n", drc_index);
+ return -EINVAL;
+ }
+
+ rc = dlpar_acquire_drc(drc_index);
+ if (rc) {
+ pr_warn("Failed to acquire DRC, rc: %d, drc index: %x\n",
+ rc, drc_index);
+ of_node_put(parent);
+ return -EINVAL;
+ }
+
+ dn = dlpar_configure_connector(cpu_to_be32(drc_index), parent);
+ if (!dn) {
+ pr_warn("Failed call to configure-connector, drc index: %x\n",
+ drc_index);
+ dlpar_release_drc(drc_index);
+ of_node_put(parent);
+ return -EINVAL;
+ }
+
+ rc = dlpar_attach_node(dn, parent);
+
+ /* Regardless we are done with parent now */
+ of_node_put(parent);
+
+ if (rc) {
+ saved_rc = rc;
+ pr_warn("Failed to attach node %s, rc: %d, drc index: %x\n",
+ dn->name, rc, drc_index);
+
+ rc = dlpar_release_drc(drc_index);
+ if (!rc)
+ dlpar_free_cc_nodes(dn);
+
+ return saved_rc;
+ }
+
+ rc = dlpar_online_cpu(dn);
+ if (rc) {
+ saved_rc = rc;
+ pr_warn("Failed to online cpu %s, rc: %d, drc index: %x\n",
+ dn->name, rc, drc_index);
+
+ rc = dlpar_detach_node(dn);
+ if (!rc)
+ dlpar_release_drc(drc_index);
+
+ return saved_rc;
+ }
+
+ pr_debug("Successfully added CPU %s, drc index: %x\n", dn->name,
+ drc_index);
+ return rc;
+}
+
+static int dlpar_offline_cpu(struct device_node *dn)
+{
+ int rc = 0;
+ unsigned int cpu;
+ int len, nthreads, i;
+ const __be32 *intserv;
+ u32 thread;
+
+ 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++) {
+ thread = be32_to_cpu(intserv[i]);
+ for_each_present_cpu(cpu) {
+ if (get_hard_smp_processor_id(cpu) != thread)
+ continue;
+
+ if (get_cpu_current_state(cpu) == CPU_STATE_OFFLINE)
+ break;
+
+ if (get_cpu_current_state(cpu) == CPU_STATE_ONLINE) {
+ set_preferred_offline_state(cpu,
+ CPU_STATE_OFFLINE);
+ cpu_maps_update_done();
+ timed_topology_update(1);
+ rc = device_offline(get_cpu_device(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, thread)
+ != 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", thread);
+ }
+ cpu_maps_update_done();
+
+out:
+ return rc;
+
+}
+
+static ssize_t dlpar_cpu_remove(struct device_node *dn, u32 drc_index)
+{
+ int rc;
+
+ pr_debug("Attempting to remove CPU %s, drc index: %x\n",
+ dn->name, drc_index);
+
+ rc = dlpar_offline_cpu(dn);
+ if (rc) {
+ pr_warn("Failed to offline CPU %s, rc: %d\n", dn->name, rc);
+ return -EINVAL;
+ }
+
+ rc = dlpar_release_drc(drc_index);
+ if (rc) {
+ pr_warn("Failed to release drc (%x) for CPU %s, rc: %d\n",
+ drc_index, dn->name, rc);
+ dlpar_online_cpu(dn);
+ return rc;
+ }
+
+ rc = dlpar_detach_node(dn);
+ if (rc) {
+ int saved_rc = rc;
+
+ pr_warn("Failed to detach CPU %s, rc: %d", dn->name, rc);
+
+ rc = dlpar_acquire_drc(drc_index);
+ if (!rc)
+ dlpar_online_cpu(dn);
+
+ return saved_rc;
+ }
+
+ pr_debug("Successfully removed CPU, drc index: %x\n", drc_index);
+ return 0;
+}
+
+static struct device_node *cpu_drc_index_to_dn(u32 drc_index)
+{
+ struct device_node *dn;
+ u32 my_index;
+ int rc;
+
+ for_each_node_by_type(dn, "cpu") {
+ rc = of_property_read_u32(dn, "ibm,my-drc-index", &my_index);
+ if (rc)
+ continue;
+
+ if (my_index == drc_index)
+ break;
+ }
+
+ return dn;
+}
+
+static int dlpar_cpu_remove_by_index(u32 drc_index)
+{
+ struct device_node *dn;
+ int rc;
+
+ dn = cpu_drc_index_to_dn(drc_index);
+ if (!dn) {
+ pr_warn("Cannot find CPU (drc index %x) to remove\n",
+ drc_index);
+ return -ENODEV;
+ }
+
+ rc = dlpar_cpu_remove(dn, drc_index);
+ of_node_put(dn);
+ return rc;
+}
+
+static int find_dlpar_cpus_to_remove(u32 *cpu_drcs, int cpus_to_remove)
+{
+ struct device_node *dn;
+ int cpus_found = 0;
+ int rc;
+
+ /* We want to find cpus_to_remove + 1 CPUs to ensure we do not
+ * remove the last CPU.
+ */
+ for_each_node_by_type(dn, "cpu") {
+ cpus_found++;
+
+ if (cpus_found > cpus_to_remove) {
+ of_node_put(dn);
+ break;
+ }
+
+ /* Note that cpus_found is always 1 ahead of the index
+ * into the cpu_drcs array, so we use cpus_found - 1
+ */
+ rc = of_property_read_u32(dn, "ibm,my-drc-index",
+ &cpu_drcs[cpus_found - 1]);
+ if (rc) {
+ pr_warn("Error occurred getting drc-index for %s\n",
+ dn->name);
+ of_node_put(dn);
+ return -1;
+ }
+ }
+
+ if (cpus_found < cpus_to_remove) {
+ pr_warn("Failed to find enough CPUs (%d of %d) to remove\n",
+ cpus_found, cpus_to_remove);
+ } else if (cpus_found == cpus_to_remove) {
+ pr_warn("Cannot remove all CPUs\n");
+ }
+
+ return cpus_found;
+}
+
+static int dlpar_cpu_remove_by_count(u32 cpus_to_remove)
+{
+ u32 *cpu_drcs;
+ int cpus_found;
+ int cpus_removed = 0;
+ int i, rc;
+
+ pr_debug("Attempting to hot-remove %d CPUs\n", cpus_to_remove);
+
+ cpu_drcs = kcalloc(cpus_to_remove, sizeof(*cpu_drcs), GFP_KERNEL);
+ if (!cpu_drcs)
+ return -EINVAL;
+
+ cpus_found = find_dlpar_cpus_to_remove(cpu_drcs, cpus_to_remove);
+ if (cpus_found <= cpus_to_remove) {
+ kfree(cpu_drcs);
+ return -EINVAL;
+ }
+
+ for (i = 0; i < cpus_to_remove; i++) {
+ rc = dlpar_cpu_remove_by_index(cpu_drcs[i]);
+ if (rc)
+ break;
+
+ cpus_removed++;
+ }
+
+ if (cpus_removed != cpus_to_remove) {
+ pr_warn("CPU hot-remove failed, adding back removed CPUs\n");
+
+ for (i = 0; i < cpus_removed; i++)
+ dlpar_cpu_add(cpu_drcs[i]);
+
+ rc = -EINVAL;
+ } else {
+ rc = 0;
+ }
+
+ kfree(cpu_drcs);
+ return rc;
+}
+
+static int find_dlpar_cpus_to_add(u32 *cpu_drcs, u32 cpus_to_add)
+{
+ struct device_node *parent;
+ int cpus_found = 0;
+ int index, rc;
+
+ parent = of_find_node_by_path("/cpus");
+ if (!parent) {
+ pr_warn("Could not find CPU root node in device tree\n");
+ kfree(cpu_drcs);
+ return -1;
+ }
+
+ /* Search the ibm,drc-indexes array for possible CPU drcs to
+ * add. Note that the format of the ibm,drc-indexes array is
+ * the number of entries in the array followed by the array
+ * of drc values so we start looking at index = 1.
+ */
+ index = 1;
+ while (cpus_found < cpus_to_add) {
+ u32 drc;
+
+ rc = of_property_read_u32_index(parent, "ibm,drc-indexes",
+ index++, &drc);
+ if (rc)
+ break;
+
+ if (dlpar_cpu_exists(parent, drc))
+ continue;
+
+ cpu_drcs[cpus_found++] = drc;
+ }
+
+ of_node_put(parent);
+ return cpus_found;
+}
+
+static int dlpar_cpu_add_by_count(u32 cpus_to_add)
+{
+ u32 *cpu_drcs;
+ int cpus_added = 0;
+ int cpus_found;
+ int i, rc;
+
+ pr_debug("Attempting to hot-add %d CPUs\n", cpus_to_add);
+
+ cpu_drcs = kcalloc(cpus_to_add, sizeof(*cpu_drcs), GFP_KERNEL);
+ if (!cpu_drcs)
+ return -EINVAL;
+
+ cpus_found = find_dlpar_cpus_to_add(cpu_drcs, cpus_to_add);
+ if (cpus_found < cpus_to_add) {
+ pr_warn("Failed to find enough CPUs (%d of %d) to add\n",
+ cpus_found, cpus_to_add);
+ kfree(cpu_drcs);
+ return -EINVAL;
+ }
+
+ for (i = 0; i < cpus_to_add; i++) {
+ rc = dlpar_cpu_add(cpu_drcs[i]);
+ if (rc)
+ break;
+
+ cpus_added++;
+ }
+
+ if (cpus_added < cpus_to_add) {
+ pr_warn("CPU hot-add failed, removing any added CPUs\n");
+
+ for (i = 0; i < cpus_added; i++)
+ dlpar_cpu_remove_by_index(cpu_drcs[i]);
+
+ rc = -EINVAL;
+ } else {
+ rc = 0;
+ }
+
+ kfree(cpu_drcs);
+ return rc;
+}
+
+int dlpar_cpu_readd(int cpu)
+{
+ struct device_node *dn;
+ struct device *dev;
+ u32 drc_index;
+ int rc;
+
+ dev = get_cpu_device(cpu);
+ dn = dev->of_node;
+
+ rc = of_property_read_u32(dn, "ibm,my-drc-index", &drc_index);
+
+ rc = dlpar_cpu_remove_by_index(drc_index);
+ if (!rc)
+ rc = dlpar_cpu_add(drc_index);
+
+ return rc;
+}
+
+int dlpar_cpu(struct pseries_hp_errorlog *hp_elog)
+{
+ u32 count, drc_index;
+ int rc;
+
+ count = hp_elog->_drc_u.drc_count;
+ drc_index = hp_elog->_drc_u.drc_index;
+
+ lock_device_hotplug();
+
+ switch (hp_elog->action) {
+ case PSERIES_HP_ELOG_ACTION_REMOVE:
+ if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_COUNT)
+ rc = dlpar_cpu_remove_by_count(count);
+ else if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_INDEX)
+ rc = dlpar_cpu_remove_by_index(drc_index);
+ else
+ rc = -EINVAL;
+ break;
+ case PSERIES_HP_ELOG_ACTION_ADD:
+ if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_COUNT)
+ rc = dlpar_cpu_add_by_count(count);
+ else if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_INDEX)
+ rc = dlpar_cpu_add(drc_index);
+ else
+ rc = -EINVAL;
+ break;
+ default:
+ pr_err("Invalid action (%d) specified\n", hp_elog->action);
+ rc = -EINVAL;
+ break;
+ }
+
+ unlock_device_hotplug();
+ return rc;
+}
+
+#ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
+
+static ssize_t dlpar_cpu_probe(const char *buf, size_t count)
+{
+ u32 drc_index;
+ int rc;
+
+ rc = kstrtou32(buf, 0, &drc_index);
+ if (rc)
+ return -EINVAL;
+
+ rc = dlpar_cpu_add(drc_index);
+
+ return rc ? rc : count;
+}
+
+static ssize_t dlpar_cpu_release(const char *buf, size_t count)
+{
+ struct device_node *dn;
+ u32 drc_index;
+ int rc;
+
+ dn = of_find_node_by_path(buf);
+ if (!dn)
+ return -EINVAL;
+
+ rc = of_property_read_u32(dn, "ibm,my-drc-index", &drc_index);
+ if (rc) {
+ of_node_put(dn);
+ return -EINVAL;
+ }
+
+ rc = dlpar_cpu_remove(dn, drc_index);
+ of_node_put(dn);
+
+ return rc ? rc : count;
+}
+
+#endif /* CONFIG_ARCH_CPU_PROBE_RELEASE */
+
+static int pseries_smp_notifier(struct notifier_block *nb,
+ unsigned long action, void *data)
+{
+ struct of_reconfig_data *rd = data;
+ int err = 0;
+
+ switch (action) {
+ case OF_RECONFIG_ATTACH_NODE:
+ err = pseries_add_processor(rd->dn);
+ break;
+ case OF_RECONFIG_DETACH_NODE:
+ pseries_remove_processor(rd->dn);
+ break;
+ }
+ return notifier_from_errno(err);
+}
+
+static struct notifier_block pseries_smp_nb = {
+ .notifier_call = pseries_smp_notifier,
+};
+
+#define MAX_CEDE_LATENCY_LEVELS 4
+#define CEDE_LATENCY_PARAM_LENGTH 10
+#define CEDE_LATENCY_PARAM_MAX_LENGTH \
+ (MAX_CEDE_LATENCY_LEVELS * CEDE_LATENCY_PARAM_LENGTH * sizeof(char))
+#define CEDE_LATENCY_TOKEN 45
+
+static char cede_parameters[CEDE_LATENCY_PARAM_MAX_LENGTH];
+
+static int parse_cede_parameters(void)
+{
+ memset(cede_parameters, 0, CEDE_LATENCY_PARAM_MAX_LENGTH);
+ return rtas_call(rtas_token("ibm,get-system-parameter"), 3, 1,
+ NULL,
+ CEDE_LATENCY_TOKEN,
+ __pa(cede_parameters),
+ CEDE_LATENCY_PARAM_MAX_LENGTH);
+}
+
+static int __init pseries_cpu_hotplug_init(void)
+{
+ int cpu;
+ int qcss_tok;
+
+#ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
+ ppc_md.cpu_probe = dlpar_cpu_probe;
+ ppc_md.cpu_release = dlpar_cpu_release;
+#endif /* CONFIG_ARCH_CPU_PROBE_RELEASE */
+
+ rtas_stop_self_token = rtas_token("stop-self");
+ qcss_tok = rtas_token("query-cpu-stopped-state");
+
+ if (rtas_stop_self_token == RTAS_UNKNOWN_SERVICE ||
+ qcss_tok == RTAS_UNKNOWN_SERVICE) {
+ printk(KERN_INFO "CPU Hotplug not supported by firmware "
+ "- disabling.\n");
+ return 0;
+ }
+
+ ppc_md.cpu_die = pseries_mach_cpu_die;
+ smp_ops->cpu_disable = pseries_cpu_disable;
+ smp_ops->cpu_die = pseries_cpu_die;
+
+ /* Processors can be added/removed only on LPAR */
+ if (firmware_has_feature(FW_FEATURE_LPAR)) {
+ of_reconfig_notifier_register(&pseries_smp_nb);
+ cpu_maps_update_begin();
+ if (cede_offline_enabled && parse_cede_parameters() == 0) {
+ default_offline_state = CPU_STATE_INACTIVE;
+ for_each_online_cpu(cpu)
+ set_default_offline_state(cpu);
+ }
+ cpu_maps_update_done();
+ }
+
+ return 0;
+}
+machine_arch_initcall(pseries, pseries_cpu_hotplug_init);