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/*
* 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.
*/
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/cpu.h>
#include <asm/system.h>
#include <asm/prom.h>
#include <asm/rtas.h>
#include <asm/firmware.h>
#include <asm/machdep.h>
#include <asm/vdso_datapage.h>
#include <asm/pSeries_reconfig.h>
#include "xics.h"
/* This version can't take the spinlock, because it never returns */
static struct rtas_args rtas_stop_self_args = {
.token = RTAS_UNKNOWN_SERVICE,
.nargs = 0,
.nret = 1,
.rets = &rtas_stop_self_args.args[0],
};
static void rtas_stop_self(void)
{
struct rtas_args *args = &rtas_stop_self_args;
local_irq_disable();
BUG_ON(args->token == RTAS_UNKNOWN_SERVICE);
printk("cpu %u (hwid %u) Ready to die...\n",
smp_processor_id(), hard_smp_processor_id());
enter_rtas(__pa(args));
panic("Alas, I survived.\n");
}
static void pSeries_mach_cpu_die(void)
{
local_irq_disable();
idle_task_exit();
xics_teardown_cpu(0);
rtas_stop_self();
/* Should never get here... */
BUG();
for(;;);
}
static int qcss_tok; /* query-cpu-stopped-state token */
/* Get state of physical CPU.
* Return codes:
* 0 - The processor is in the RTAS stopped state
* 1 - stop-self is in progress
* 2 - The processor is not in the RTAS stopped state
* -1 - Hardware Error
* -2 - Hardware Busy, Try again later.
*/
static int query_cpu_stopped(unsigned int pcpu)
{
int cpu_status, status;
status = rtas_call(qcss_tok, 1, 2, &cpu_status, pcpu);
if (status != 0) {
printk(KERN_ERR
"RTAS query-cpu-stopped-state failed: %i\n", status);
return status;
}
return cpu_status;
}
static int pSeries_cpu_disable(void)
{
int cpu = smp_processor_id();
cpu_clear(cpu, cpu_online_map);
vdso_data->processorCount--;
/*fix boot_cpuid here*/
if (cpu == boot_cpuid)
boot_cpuid = any_online_cpu(cpu_online_map);
/* FIXME: abstract this to not be platform specific later on */
xics_migrate_irqs_away();
return 0;
}
static void pSeries_cpu_die(unsigned int cpu)
{
int tries;
int cpu_status;
unsigned int pcpu = get_hard_smp_processor_id(cpu);
for (tries = 0; tries < 25; tries++) {
cpu_status = query_cpu_stopped(pcpu);
if (cpu_status == 0 || cpu_status == -1)
break;
msleep(200);
}
if (cpu_status != 0) {
printk("Querying DEAD? cpu %i (%i) shows %i\n",
cpu, pcpu, cpu_status);
}
/* Isolation and deallocation are definatly 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[cpu].cpu_start = 0;
}
/*
* 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;
const u32 *intserv;
intserv = 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;
const u32 *intserv;
intserv = 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,
};
static int __init pseries_cpu_hotplug_init(void)
{
rtas_stop_self_args.token = rtas_token("stop-self");
qcss_tok = rtas_token("query-cpu-stopped-state");
if (rtas_stop_self_args.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))
pSeries_reconfig_notifier_register(&pSeries_smp_nb);
return 0;
}
arch_initcall(pseries_cpu_hotplug_init);
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