blob: 0f8cd8b06432d21a02bd0ddae4a0b8677de962ae [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* 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
*/
#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"
/* This version can't take the spinlock, because it never returns */
static int rtas_stop_self_token = RTAS_UNKNOWN_SERVICE;
/*
* Record the CPU ids used on each nodes.
* Protected by cpu_add_remove_lock.
*/
static cpumask_var_t node_recorded_ids_map[MAX_NUMNODES];
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_cpu_offline_self(void)
{
unsigned int hwcpu = hard_smp_processor_id();
local_irq_disable();
idle_task_exit();
if (xive_enabled())
xive_teardown_cpu();
else
xics_teardown_cpu();
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();
cleanup_cpu_mmu_context();
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_cpu_offline_self() is called by the @cpu when it wants to
* self-destruct.
*/
static void pseries_cpu_die(unsigned int cpu)
{
int cpu_status = 1;
unsigned int pcpu = get_hard_smp_processor_id(cpu);
unsigned long timeout = jiffies + msecs_to_jiffies(120000);
while (true) {
cpu_status = smp_query_cpu_stopped(pcpu);
if (cpu_status == QCSS_STOPPED ||
cpu_status == QCSS_HARDWARE_ERROR)
break;
if (time_after(jiffies, timeout)) {
pr_warn("CPU %i (hwid %i) didn't die after 120 seconds\n",
cpu, pcpu);
timeout = jiffies + msecs_to_jiffies(120000);
}
cond_resched();
}
if (cpu_status == QCSS_HARDWARE_ERROR) {
pr_warn("CPU %i (hwid %i) reported error while dying\n",
cpu, pcpu);
}
paca_ptrs[cpu]->cpu_start = 0;
}
/**
* find_cpu_id_range - found a linear ranger of @nthreads free CPU ids.
* @nthreads : the number of threads (cpu ids)
* @assigned_node : the node it belongs to or NUMA_NO_NODE if free ids from any
* node can be peek.
* @cpu_mask: the returned CPU mask.
*
* Returns 0 on success.
*/
static int find_cpu_id_range(unsigned int nthreads, int assigned_node,
cpumask_var_t *cpu_mask)
{
cpumask_var_t candidate_mask;
unsigned int cpu, node;
int rc = -ENOSPC;
if (!zalloc_cpumask_var(&candidate_mask, GFP_KERNEL))
return -ENOMEM;
cpumask_clear(*cpu_mask);
for (cpu = 0; cpu < nthreads; cpu++)
cpumask_set_cpu(cpu, *cpu_mask);
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 (assigned_node != NUMA_NO_NODE) {
/*
* Remove free ids previously assigned on the other nodes. We
* can walk only online nodes because once a node became online
* it is not turned offlined back.
*/
for_each_online_node(node) {
if (node == assigned_node)
continue;
cpumask_andnot(candidate_mask, candidate_mask,
node_recorded_ids_map[node]);
}
}
if (cpumask_empty(candidate_mask))
goto out;
while (!cpumask_empty(*cpu_mask)) {
if (cpumask_subset(*cpu_mask, candidate_mask))
/* Found a range where we can insert the new cpu(s) */
break;
cpumask_shift_left(*cpu_mask, *cpu_mask, nthreads);
}
if (!cpumask_empty(*cpu_mask))
rc = 0;
out:
free_cpumask_var(candidate_mask);
return rc;
}
/*
* Update cpu_present_mask and paca(s) for a new cpu node. The wrinkle
* here is that a cpu device node may represent multiple 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)
{
int len, nthreads, node, cpu, assigned_node;
int rc = 0;
cpumask_var_t cpu_mask;
const __be32 *intserv;
intserv = of_get_property(np, "ibm,ppc-interrupt-server#s", &len);
if (!intserv)
return 0;
nthreads = len / sizeof(u32);
if (!alloc_cpumask_var(&cpu_mask, GFP_KERNEL))
return -ENOMEM;
/*
* Fetch from the DT nodes read by dlpar_configure_connector() the NUMA
* node id the added CPU belongs to.
*/
node = of_node_to_nid(np);
if (node < 0 || !node_possible(node))
node = first_online_node;
BUG_ON(node == NUMA_NO_NODE);
assigned_node = node;
cpu_maps_update_begin();
rc = find_cpu_id_range(nthreads, node, &cpu_mask);
if (rc && nr_node_ids > 1) {
/*
* Try again, considering the free CPU ids from the other node.
*/
node = NUMA_NO_NODE;
rc = find_cpu_id_range(nthreads, NUMA_NO_NODE, &cpu_mask);
}
if (rc) {
pr_err("Cannot add cpu %pOF; this system configuration"
" supports %d logical cpus.\n", np, num_possible_cpus());
goto out;
}
for_each_cpu(cpu, cpu_mask) {
BUG_ON(cpu_present(cpu));
set_cpu_present(cpu, true);
set_hard_smp_processor_id(cpu, be32_to_cpu(*intserv++));
}
/* Record the newly used CPU ids for the associate node. */
cpumask_or(node_recorded_ids_map[assigned_node],
node_recorded_ids_map[assigned_node], cpu_mask);
/*
* If node is set to NUMA_NO_NODE, CPU ids have be reused from
* another node, remove them from its mask.
*/
if (node == NUMA_NO_NODE) {
cpu = cpumask_first(cpu_mask);
pr_warn("Reusing free CPU ids %d-%d from another node\n",
cpu, cpu + nthreads - 1);
for_each_online_node(node) {
if (node == assigned_node)
continue;
cpumask_andnot(node_recorded_ids_map[node],
node_recorded_ids_map[node],
cpu_mask);
}
}
out:
cpu_maps_update_done();
free_cpumask_var(cpu_mask);
return rc;
}
/*
* 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_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 (!cpu_online(cpu))
break;
/*
* device_offline() will return -EBUSY (via cpu_down()) if there
* is only one CPU left. Check it here to fail earlier and with a
* more informative error message, while also retaining the
* cpu_add_remove_lock to be sure that no CPUs are being
* online/offlined during this check.
*/
if (num_online_cpus() == 1) {
pr_warn("Unable to remove last online CPU %pOFn\n", dn);
rc = -EBUSY;
goto out_unlock;
}
cpu_maps_update_done();
rc = device_offline(get_cpu_device(cpu));
if (rc)
goto out;
cpu_maps_update_begin();
break;
}
if (cpu == num_possible_cpus()) {
pr_warn("Could not find cpu to offline with physical id 0x%x\n",
thread);
}
}
out_unlock:
cpu_maps_update_done();
out:
return rc;
}
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;
cpu_maps_update_done();
find_and_update_cpu_nid(cpu);
rc = device_online(get_cpu_device(cpu));
if (rc) {
dlpar_offline_cpu(dn);
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 drc_info_valid_index(struct device_node *parent, u32 drc_index)
{
struct property *info;
struct of_drc_info drc;
const __be32 *value;
u32 index;
int count, i, j;
info = of_find_property(parent, "ibm,drc-info", NULL);
if (!info)
return false;
value = of_prop_next_u32(info, NULL, &count);
/* First value of ibm,drc-info is number of drc-info records */
if (value)
value++;
else
return false;
for (i = 0; i < count; i++) {
if (of_read_drc_info_cell(&info, &value, &drc))
return false;
if (strncmp(drc.drc_type, "CPU", 3))
break;
if (drc_index > drc.last_drc_index)
continue;
index = drc.drc_index_start;
for (j = 0; j < drc.num_sequential_elems; j++) {
if (drc_index == index)
return true;
index += drc.sequential_inc;
}
}
return false;
}
static bool valid_cpu_drc_index(struct device_node *parent, u32 drc_index)
{
bool found = false;
int rc, index;
if (of_find_property(parent, "ibm,drc-info", NULL))
return drc_info_valid_index(parent, drc_index);
/* 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 (!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 int pseries_cpuhp_attach_nodes(struct device_node *dn)
{
struct of_changeset cs;
int ret;
/*
* This device node is unattached but may have siblings; open-code the
* traversal.
*/
for (of_changeset_init(&cs); dn != NULL; dn = dn->sibling) {
ret = of_changeset_attach_node(&cs, dn);
if (ret)
goto out;
}
ret = of_changeset_apply(&cs);
out:
of_changeset_destroy(&cs);
return ret;
}
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 = pseries_cpuhp_attach_nodes(dn);
/* Regardless we are done with parent now */
of_node_put(parent);
if (rc) {
saved_rc = rc;
pr_warn("Failed to attach node %pOFn, rc: %d, drc index: %x\n",
dn, rc, drc_index);
rc = dlpar_release_drc(drc_index);
if (!rc)
dlpar_free_cc_nodes(dn);
return saved_rc;
}
update_numa_distance(dn);
rc = dlpar_online_cpu(dn);
if (rc) {
saved_rc = rc;
pr_warn("Failed to online cpu %pOFn, rc: %d, drc index: %x\n",
dn, rc, drc_index);
rc = dlpar_detach_node(dn);
if (!rc)
dlpar_release_drc(drc_index);
return saved_rc;
}
pr_debug("Successfully added CPU %pOFn, drc index: %x\n", dn,
drc_index);
return rc;
}
static unsigned int pseries_cpuhp_cache_use_count(const struct device_node *cachedn)
{
unsigned int use_count = 0;
struct device_node *dn;
WARN_ON(!of_node_is_type(cachedn, "cache"));
for_each_of_cpu_node(dn) {
if (of_find_next_cache_node(dn) == cachedn)
use_count++;
}
for_each_node_by_type(dn, "cache") {
if (of_find_next_cache_node(dn) == cachedn)
use_count++;
}
return use_count;
}
static int pseries_cpuhp_detach_nodes(struct device_node *cpudn)
{
struct device_node *dn;
struct of_changeset cs;
int ret = 0;
of_changeset_init(&cs);
ret = of_changeset_detach_node(&cs, cpudn);
if (ret)
goto out;
dn = cpudn;
while ((dn = of_find_next_cache_node(dn))) {
if (pseries_cpuhp_cache_use_count(dn) > 1)
break;
ret = of_changeset_detach_node(&cs, dn);
if (ret)
goto out;
}
ret = of_changeset_apply(&cs);
out:
of_changeset_destroy(&cs);
return ret;
}
static ssize_t dlpar_cpu_remove(struct device_node *dn, u32 drc_index)
{
int rc;
pr_debug("Attempting to remove CPU %pOFn, drc index: %x\n",
dn, drc_index);
rc = dlpar_offline_cpu(dn);
if (rc) {
pr_warn("Failed to offline CPU %pOFn, rc: %d\n", dn, rc);
return -EINVAL;
}
rc = dlpar_release_drc(drc_index);
if (rc) {
pr_warn("Failed to release drc (%x) for CPU %pOFn, rc: %d\n",
drc_index, dn, rc);
dlpar_online_cpu(dn);
return rc;
}
rc = pseries_cpuhp_detach_nodes(dn);
if (rc) {
int saved_rc = rc;
pr_warn("Failed to detach CPU %pOFn, rc: %d", dn, 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;
}
int dlpar_cpu(struct pseries_hp_errorlog *hp_elog)
{
u32 drc_index;
int rc;
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_INDEX) {
rc = dlpar_cpu_remove_by_index(drc_index);
/*
* Setting the isolation state of an UNISOLATED/CONFIGURED
* device to UNISOLATE is a no-op, but the hypervisor can
* use it as a hint that the CPU removal failed.
*/
if (rc)
dlpar_unisolate_drc(drc_index);
}
else
rc = -EINVAL;
break;
case PSERIES_HP_ELOG_ACTION_ADD:
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,
};
static int __init pseries_cpu_hotplug_init(void)
{
int qcss_tok;
unsigned int node;
#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;
}
smp_ops->cpu_offline_self = pseries_cpu_offline_self;
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)) {
for_each_node(node) {
if (!alloc_cpumask_var_node(&node_recorded_ids_map[node],
GFP_KERNEL, node))
return -ENOMEM;
/* Record ids of CPU added at boot time */
cpumask_copy(node_recorded_ids_map[node],
cpumask_of_node(node));
}
of_reconfig_notifier_register(&pseries_smp_nb);
}
return 0;
}
machine_arch_initcall(pseries, pseries_cpu_hotplug_init);