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linux/arch/powerpc/kernel/sysfs.c
Anton Blanchard b878dc0059 powerpc: Use smt_snooze_delay=-1 to always busy loop 
Right now if we want to busy loop and not give up any time to the hypervisor
we put a very large value into smt_snooze_delay. This is sometimes useful
when running a single partition and you want to avoid any latencies due
to the hypervisor or CPU power state transitions. While this works, it's a bit
ugly - how big a number is enough now we have NO_HZ and can be idle for a very
long time.

The patch below makes smt_snooze_delay signed, and a negative value means loop
forever:

echo -1 > /sys/devices/system/cpu/cpu0/smt_snooze_delay

This change shouldn't affect the existing userspace tools (eg ppc64_cpu), but
I'm cc-ing Nathan just to be sure.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2010-05-21 17:31:12 +10:00

624 lines
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#include <linux/sysdev.h>
#include <linux/cpu.h>
#include <linux/smp.h>
#include <linux/percpu.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/module.h>
#include <linux/nodemask.h>
#include <linux/cpumask.h>
#include <linux/notifier.h>
#include <asm/current.h>
#include <asm/processor.h>
#include <asm/cputable.h>
#include <asm/firmware.h>
#include <asm/hvcall.h>
#include <asm/prom.h>
#include <asm/machdep.h>
#include <asm/smp.h>
#include <asm/pmc.h>
#include "cacheinfo.h"
#ifdef CONFIG_PPC64
#include <asm/paca.h>
#include <asm/lppaca.h>
#endif
static DEFINE_PER_CPU(struct cpu, cpu_devices);
/*
* SMT snooze delay stuff, 64-bit only for now
*/
#ifdef CONFIG_PPC64
/* Time in microseconds we delay before sleeping in the idle loop */
DEFINE_PER_CPU(long, smt_snooze_delay) = { 100 };
static ssize_t store_smt_snooze_delay(struct sys_device *dev,
struct sysdev_attribute *attr,
const char *buf,
size_t count)
{
struct cpu *cpu = container_of(dev, struct cpu, sysdev);
ssize_t ret;
long snooze;
ret = sscanf(buf, "%ld", &snooze);
if (ret != 1)
return -EINVAL;
per_cpu(smt_snooze_delay, cpu->sysdev.id) = snooze;
return count;
}
static ssize_t show_smt_snooze_delay(struct sys_device *dev,
struct sysdev_attribute *attr,
char *buf)
{
struct cpu *cpu = container_of(dev, struct cpu, sysdev);
return sprintf(buf, "%ld\n", per_cpu(smt_snooze_delay, cpu->sysdev.id));
}
static SYSDEV_ATTR(smt_snooze_delay, 0644, show_smt_snooze_delay,
store_smt_snooze_delay);
static int __init setup_smt_snooze_delay(char *str)
{
unsigned int cpu;
long snooze;
if (!cpu_has_feature(CPU_FTR_SMT))
return 1;
snooze = simple_strtol(str, NULL, 10);
for_each_possible_cpu(cpu)
per_cpu(smt_snooze_delay, cpu) = snooze;
return 1;
}
__setup("smt-snooze-delay=", setup_smt_snooze_delay);
#endif /* CONFIG_PPC64 */
/*
* Enabling PMCs will slow partition context switch times so we only do
* it the first time we write to the PMCs.
*/
static DEFINE_PER_CPU(char, pmcs_enabled);
void ppc_enable_pmcs(void)
{
ppc_set_pmu_inuse(1);
/* Only need to enable them once */
if (__get_cpu_var(pmcs_enabled))
return;
__get_cpu_var(pmcs_enabled) = 1;
if (ppc_md.enable_pmcs)
ppc_md.enable_pmcs();
}
EXPORT_SYMBOL(ppc_enable_pmcs);
#define SYSFS_PMCSETUP(NAME, ADDRESS) \
static void read_##NAME(void *val) \
{ \
*(unsigned long *)val = mfspr(ADDRESS); \
} \
static void write_##NAME(void *val) \
{ \
ppc_enable_pmcs(); \
mtspr(ADDRESS, *(unsigned long *)val); \
} \
static ssize_t show_##NAME(struct sys_device *dev, \
struct sysdev_attribute *attr, \
char *buf) \
{ \
struct cpu *cpu = container_of(dev, struct cpu, sysdev); \
unsigned long val; \
smp_call_function_single(cpu->sysdev.id, read_##NAME, &val, 1); \
return sprintf(buf, "%lx\n", val); \
} \
static ssize_t __used \
store_##NAME(struct sys_device *dev, struct sysdev_attribute *attr, \
const char *buf, size_t count) \
{ \
struct cpu *cpu = container_of(dev, struct cpu, sysdev); \
unsigned long val; \
int ret = sscanf(buf, "%lx", &val); \
if (ret != 1) \
return -EINVAL; \
smp_call_function_single(cpu->sysdev.id, write_##NAME, &val, 1); \
return count; \
}
/* Let's define all possible registers, we'll only hook up the ones
* that are implemented on the current processor
*/
#if defined(CONFIG_PPC64)
#define HAS_PPC_PMC_CLASSIC 1
#define HAS_PPC_PMC_IBM 1
#define HAS_PPC_PMC_PA6T 1
#elif defined(CONFIG_6xx)
#define HAS_PPC_PMC_CLASSIC 1
#define HAS_PPC_PMC_IBM 1
#define HAS_PPC_PMC_G4 1
#endif
#ifdef HAS_PPC_PMC_CLASSIC
SYSFS_PMCSETUP(mmcr0, SPRN_MMCR0);
SYSFS_PMCSETUP(mmcr1, SPRN_MMCR1);
SYSFS_PMCSETUP(pmc1, SPRN_PMC1);
SYSFS_PMCSETUP(pmc2, SPRN_PMC2);
SYSFS_PMCSETUP(pmc3, SPRN_PMC3);
SYSFS_PMCSETUP(pmc4, SPRN_PMC4);
SYSFS_PMCSETUP(pmc5, SPRN_PMC5);
SYSFS_PMCSETUP(pmc6, SPRN_PMC6);
#ifdef HAS_PPC_PMC_G4
SYSFS_PMCSETUP(mmcr2, SPRN_MMCR2);
#endif
#ifdef CONFIG_PPC64
SYSFS_PMCSETUP(pmc7, SPRN_PMC7);
SYSFS_PMCSETUP(pmc8, SPRN_PMC8);
SYSFS_PMCSETUP(mmcra, SPRN_MMCRA);
SYSFS_PMCSETUP(purr, SPRN_PURR);
SYSFS_PMCSETUP(spurr, SPRN_SPURR);
SYSFS_PMCSETUP(dscr, SPRN_DSCR);
static SYSDEV_ATTR(mmcra, 0600, show_mmcra, store_mmcra);
static SYSDEV_ATTR(spurr, 0600, show_spurr, NULL);
static SYSDEV_ATTR(dscr, 0600, show_dscr, store_dscr);
static SYSDEV_ATTR(purr, 0600, show_purr, store_purr);
#endif /* CONFIG_PPC64 */
#ifdef HAS_PPC_PMC_PA6T
SYSFS_PMCSETUP(pa6t_pmc0, SPRN_PA6T_PMC0);
SYSFS_PMCSETUP(pa6t_pmc1, SPRN_PA6T_PMC1);
SYSFS_PMCSETUP(pa6t_pmc2, SPRN_PA6T_PMC2);
SYSFS_PMCSETUP(pa6t_pmc3, SPRN_PA6T_PMC3);
SYSFS_PMCSETUP(pa6t_pmc4, SPRN_PA6T_PMC4);
SYSFS_PMCSETUP(pa6t_pmc5, SPRN_PA6T_PMC5);
#ifdef CONFIG_DEBUG_KERNEL
SYSFS_PMCSETUP(hid0, SPRN_HID0);
SYSFS_PMCSETUP(hid1, SPRN_HID1);
SYSFS_PMCSETUP(hid4, SPRN_HID4);
SYSFS_PMCSETUP(hid5, SPRN_HID5);
SYSFS_PMCSETUP(ima0, SPRN_PA6T_IMA0);
SYSFS_PMCSETUP(ima1, SPRN_PA6T_IMA1);
SYSFS_PMCSETUP(ima2, SPRN_PA6T_IMA2);
SYSFS_PMCSETUP(ima3, SPRN_PA6T_IMA3);
SYSFS_PMCSETUP(ima4, SPRN_PA6T_IMA4);
SYSFS_PMCSETUP(ima5, SPRN_PA6T_IMA5);
SYSFS_PMCSETUP(ima6, SPRN_PA6T_IMA6);
SYSFS_PMCSETUP(ima7, SPRN_PA6T_IMA7);
SYSFS_PMCSETUP(ima8, SPRN_PA6T_IMA8);
SYSFS_PMCSETUP(ima9, SPRN_PA6T_IMA9);
SYSFS_PMCSETUP(imaat, SPRN_PA6T_IMAAT);
SYSFS_PMCSETUP(btcr, SPRN_PA6T_BTCR);
SYSFS_PMCSETUP(pccr, SPRN_PA6T_PCCR);
SYSFS_PMCSETUP(rpccr, SPRN_PA6T_RPCCR);
SYSFS_PMCSETUP(der, SPRN_PA6T_DER);
SYSFS_PMCSETUP(mer, SPRN_PA6T_MER);
SYSFS_PMCSETUP(ber, SPRN_PA6T_BER);
SYSFS_PMCSETUP(ier, SPRN_PA6T_IER);
SYSFS_PMCSETUP(sier, SPRN_PA6T_SIER);
SYSFS_PMCSETUP(siar, SPRN_PA6T_SIAR);
SYSFS_PMCSETUP(tsr0, SPRN_PA6T_TSR0);
SYSFS_PMCSETUP(tsr1, SPRN_PA6T_TSR1);
SYSFS_PMCSETUP(tsr2, SPRN_PA6T_TSR2);
SYSFS_PMCSETUP(tsr3, SPRN_PA6T_TSR3);
#endif /* CONFIG_DEBUG_KERNEL */
#endif /* HAS_PPC_PMC_PA6T */
#ifdef HAS_PPC_PMC_IBM
static struct sysdev_attribute ibm_common_attrs[] = {
_SYSDEV_ATTR(mmcr0, 0600, show_mmcr0, store_mmcr0),
_SYSDEV_ATTR(mmcr1, 0600, show_mmcr1, store_mmcr1),
};
#endif /* HAS_PPC_PMC_G4 */
#ifdef HAS_PPC_PMC_G4
static struct sysdev_attribute g4_common_attrs[] = {
_SYSDEV_ATTR(mmcr0, 0600, show_mmcr0, store_mmcr0),
_SYSDEV_ATTR(mmcr1, 0600, show_mmcr1, store_mmcr1),
_SYSDEV_ATTR(mmcr2, 0600, show_mmcr2, store_mmcr2),
};
#endif /* HAS_PPC_PMC_G4 */
static struct sysdev_attribute classic_pmc_attrs[] = {
_SYSDEV_ATTR(pmc1, 0600, show_pmc1, store_pmc1),
_SYSDEV_ATTR(pmc2, 0600, show_pmc2, store_pmc2),
_SYSDEV_ATTR(pmc3, 0600, show_pmc3, store_pmc3),
_SYSDEV_ATTR(pmc4, 0600, show_pmc4, store_pmc4),
_SYSDEV_ATTR(pmc5, 0600, show_pmc5, store_pmc5),
_SYSDEV_ATTR(pmc6, 0600, show_pmc6, store_pmc6),
#ifdef CONFIG_PPC64
_SYSDEV_ATTR(pmc7, 0600, show_pmc7, store_pmc7),
_SYSDEV_ATTR(pmc8, 0600, show_pmc8, store_pmc8),
#endif
};
#ifdef HAS_PPC_PMC_PA6T
static struct sysdev_attribute pa6t_attrs[] = {
_SYSDEV_ATTR(mmcr0, 0600, show_mmcr0, store_mmcr0),
_SYSDEV_ATTR(mmcr1, 0600, show_mmcr1, store_mmcr1),
_SYSDEV_ATTR(pmc0, 0600, show_pa6t_pmc0, store_pa6t_pmc0),
_SYSDEV_ATTR(pmc1, 0600, show_pa6t_pmc1, store_pa6t_pmc1),
_SYSDEV_ATTR(pmc2, 0600, show_pa6t_pmc2, store_pa6t_pmc2),
_SYSDEV_ATTR(pmc3, 0600, show_pa6t_pmc3, store_pa6t_pmc3),
_SYSDEV_ATTR(pmc4, 0600, show_pa6t_pmc4, store_pa6t_pmc4),
_SYSDEV_ATTR(pmc5, 0600, show_pa6t_pmc5, store_pa6t_pmc5),
#ifdef CONFIG_DEBUG_KERNEL
_SYSDEV_ATTR(hid0, 0600, show_hid0, store_hid0),
_SYSDEV_ATTR(hid1, 0600, show_hid1, store_hid1),
_SYSDEV_ATTR(hid4, 0600, show_hid4, store_hid4),
_SYSDEV_ATTR(hid5, 0600, show_hid5, store_hid5),
_SYSDEV_ATTR(ima0, 0600, show_ima0, store_ima0),
_SYSDEV_ATTR(ima1, 0600, show_ima1, store_ima1),
_SYSDEV_ATTR(ima2, 0600, show_ima2, store_ima2),
_SYSDEV_ATTR(ima3, 0600, show_ima3, store_ima3),
_SYSDEV_ATTR(ima4, 0600, show_ima4, store_ima4),
_SYSDEV_ATTR(ima5, 0600, show_ima5, store_ima5),
_SYSDEV_ATTR(ima6, 0600, show_ima6, store_ima6),
_SYSDEV_ATTR(ima7, 0600, show_ima7, store_ima7),
_SYSDEV_ATTR(ima8, 0600, show_ima8, store_ima8),
_SYSDEV_ATTR(ima9, 0600, show_ima9, store_ima9),
_SYSDEV_ATTR(imaat, 0600, show_imaat, store_imaat),
_SYSDEV_ATTR(btcr, 0600, show_btcr, store_btcr),
_SYSDEV_ATTR(pccr, 0600, show_pccr, store_pccr),
_SYSDEV_ATTR(rpccr, 0600, show_rpccr, store_rpccr),
_SYSDEV_ATTR(der, 0600, show_der, store_der),
_SYSDEV_ATTR(mer, 0600, show_mer, store_mer),
_SYSDEV_ATTR(ber, 0600, show_ber, store_ber),
_SYSDEV_ATTR(ier, 0600, show_ier, store_ier),
_SYSDEV_ATTR(sier, 0600, show_sier, store_sier),
_SYSDEV_ATTR(siar, 0600, show_siar, store_siar),
_SYSDEV_ATTR(tsr0, 0600, show_tsr0, store_tsr0),
_SYSDEV_ATTR(tsr1, 0600, show_tsr1, store_tsr1),
_SYSDEV_ATTR(tsr2, 0600, show_tsr2, store_tsr2),
_SYSDEV_ATTR(tsr3, 0600, show_tsr3, store_tsr3),
#endif /* CONFIG_DEBUG_KERNEL */
};
#endif /* HAS_PPC_PMC_PA6T */
#endif /* HAS_PPC_PMC_CLASSIC */
static void __cpuinit register_cpu_online(unsigned int cpu)
{
struct cpu *c = &per_cpu(cpu_devices, cpu);
struct sys_device *s = &c->sysdev;
struct sysdev_attribute *attrs, *pmc_attrs;
int i, nattrs;
#ifdef CONFIG_PPC64
if (!firmware_has_feature(FW_FEATURE_ISERIES) &&
cpu_has_feature(CPU_FTR_SMT))
sysdev_create_file(s, &attr_smt_snooze_delay);
#endif
/* PMC stuff */
switch (cur_cpu_spec->pmc_type) {
#ifdef HAS_PPC_PMC_IBM
case PPC_PMC_IBM:
attrs = ibm_common_attrs;
nattrs = sizeof(ibm_common_attrs) / sizeof(struct sysdev_attribute);
pmc_attrs = classic_pmc_attrs;
break;
#endif /* HAS_PPC_PMC_IBM */
#ifdef HAS_PPC_PMC_G4
case PPC_PMC_G4:
attrs = g4_common_attrs;
nattrs = sizeof(g4_common_attrs) / sizeof(struct sysdev_attribute);
pmc_attrs = classic_pmc_attrs;
break;
#endif /* HAS_PPC_PMC_G4 */
#ifdef HAS_PPC_PMC_PA6T
case PPC_PMC_PA6T:
/* PA Semi starts counting at PMC0 */
attrs = pa6t_attrs;
nattrs = sizeof(pa6t_attrs) / sizeof(struct sysdev_attribute);
pmc_attrs = NULL;
break;
#endif /* HAS_PPC_PMC_PA6T */
default:
attrs = NULL;
nattrs = 0;
pmc_attrs = NULL;
}
for (i = 0; i < nattrs; i++)
sysdev_create_file(s, &attrs[i]);
if (pmc_attrs)
for (i = 0; i < cur_cpu_spec->num_pmcs; i++)
sysdev_create_file(s, &pmc_attrs[i]);
#ifdef CONFIG_PPC64
if (cpu_has_feature(CPU_FTR_MMCRA))
sysdev_create_file(s, &attr_mmcra);
if (cpu_has_feature(CPU_FTR_PURR))
sysdev_create_file(s, &attr_purr);
if (cpu_has_feature(CPU_FTR_SPURR))
sysdev_create_file(s, &attr_spurr);
if (cpu_has_feature(CPU_FTR_DSCR))
sysdev_create_file(s, &attr_dscr);
#endif /* CONFIG_PPC64 */
cacheinfo_cpu_online(cpu);
}
#ifdef CONFIG_HOTPLUG_CPU
static void unregister_cpu_online(unsigned int cpu)
{
struct cpu *c = &per_cpu(cpu_devices, cpu);
struct sys_device *s = &c->sysdev;
struct sysdev_attribute *attrs, *pmc_attrs;
int i, nattrs;
BUG_ON(!c->hotpluggable);
#ifdef CONFIG_PPC64
if (!firmware_has_feature(FW_FEATURE_ISERIES) &&
cpu_has_feature(CPU_FTR_SMT))
sysdev_remove_file(s, &attr_smt_snooze_delay);
#endif
/* PMC stuff */
switch (cur_cpu_spec->pmc_type) {
#ifdef HAS_PPC_PMC_IBM
case PPC_PMC_IBM:
attrs = ibm_common_attrs;
nattrs = sizeof(ibm_common_attrs) / sizeof(struct sysdev_attribute);
pmc_attrs = classic_pmc_attrs;
break;
#endif /* HAS_PPC_PMC_IBM */
#ifdef HAS_PPC_PMC_G4
case PPC_PMC_G4:
attrs = g4_common_attrs;
nattrs = sizeof(g4_common_attrs) / sizeof(struct sysdev_attribute);
pmc_attrs = classic_pmc_attrs;
break;
#endif /* HAS_PPC_PMC_G4 */
#ifdef HAS_PPC_PMC_PA6T
case PPC_PMC_PA6T:
/* PA Semi starts counting at PMC0 */
attrs = pa6t_attrs;
nattrs = sizeof(pa6t_attrs) / sizeof(struct sysdev_attribute);
pmc_attrs = NULL;
break;
#endif /* HAS_PPC_PMC_PA6T */
default:
attrs = NULL;
nattrs = 0;
pmc_attrs = NULL;
}
for (i = 0; i < nattrs; i++)
sysdev_remove_file(s, &attrs[i]);
if (pmc_attrs)
for (i = 0; i < cur_cpu_spec->num_pmcs; i++)
sysdev_remove_file(s, &pmc_attrs[i]);
#ifdef CONFIG_PPC64
if (cpu_has_feature(CPU_FTR_MMCRA))
sysdev_remove_file(s, &attr_mmcra);
if (cpu_has_feature(CPU_FTR_PURR))
sysdev_remove_file(s, &attr_purr);
if (cpu_has_feature(CPU_FTR_SPURR))
sysdev_remove_file(s, &attr_spurr);
if (cpu_has_feature(CPU_FTR_DSCR))
sysdev_remove_file(s, &attr_dscr);
#endif /* CONFIG_PPC64 */
cacheinfo_cpu_offline(cpu);
}
#ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
ssize_t arch_cpu_probe(const char *buf, size_t count)
{
if (ppc_md.cpu_probe)
return ppc_md.cpu_probe(buf, count);
return -EINVAL;
}
ssize_t arch_cpu_release(const char *buf, size_t count)
{
if (ppc_md.cpu_release)
return ppc_md.cpu_release(buf, count);
return -EINVAL;
}
#endif /* CONFIG_ARCH_CPU_PROBE_RELEASE */
#endif /* CONFIG_HOTPLUG_CPU */
static int __cpuinit sysfs_cpu_notify(struct notifier_block *self,
unsigned long action, void *hcpu)
{
unsigned int cpu = (unsigned int)(long)hcpu;
switch (action) {
case CPU_ONLINE:
case CPU_ONLINE_FROZEN:
register_cpu_online(cpu);
break;
#ifdef CONFIG_HOTPLUG_CPU
case CPU_DEAD:
case CPU_DEAD_FROZEN:
unregister_cpu_online(cpu);
break;
#endif
}
return NOTIFY_OK;
}
static struct notifier_block __cpuinitdata sysfs_cpu_nb = {
.notifier_call = sysfs_cpu_notify,
};
static DEFINE_MUTEX(cpu_mutex);
int cpu_add_sysdev_attr(struct sysdev_attribute *attr)
{
int cpu;
mutex_lock(&cpu_mutex);
for_each_possible_cpu(cpu) {
sysdev_create_file(get_cpu_sysdev(cpu), attr);
}
mutex_unlock(&cpu_mutex);
return 0;
}
EXPORT_SYMBOL_GPL(cpu_add_sysdev_attr);
int cpu_add_sysdev_attr_group(struct attribute_group *attrs)
{
int cpu;
struct sys_device *sysdev;
int ret;
mutex_lock(&cpu_mutex);
for_each_possible_cpu(cpu) {
sysdev = get_cpu_sysdev(cpu);
ret = sysfs_create_group(&sysdev->kobj, attrs);
WARN_ON(ret != 0);
}
mutex_unlock(&cpu_mutex);
return 0;
}
EXPORT_SYMBOL_GPL(cpu_add_sysdev_attr_group);
void cpu_remove_sysdev_attr(struct sysdev_attribute *attr)
{
int cpu;
mutex_lock(&cpu_mutex);
for_each_possible_cpu(cpu) {
sysdev_remove_file(get_cpu_sysdev(cpu), attr);
}
mutex_unlock(&cpu_mutex);
}
EXPORT_SYMBOL_GPL(cpu_remove_sysdev_attr);
void cpu_remove_sysdev_attr_group(struct attribute_group *attrs)
{
int cpu;
struct sys_device *sysdev;
mutex_lock(&cpu_mutex);
for_each_possible_cpu(cpu) {
sysdev = get_cpu_sysdev(cpu);
sysfs_remove_group(&sysdev->kobj, attrs);
}
mutex_unlock(&cpu_mutex);
}
EXPORT_SYMBOL_GPL(cpu_remove_sysdev_attr_group);
/* NUMA stuff */
#ifdef CONFIG_NUMA
static void register_nodes(void)
{
int i;
for (i = 0; i < MAX_NUMNODES; i++)
register_one_node(i);
}
int sysfs_add_device_to_node(struct sys_device *dev, int nid)
{
struct node *node = &node_devices[nid];
return sysfs_create_link(&node->sysdev.kobj, &dev->kobj,
kobject_name(&dev->kobj));
}
EXPORT_SYMBOL_GPL(sysfs_add_device_to_node);
void sysfs_remove_device_from_node(struct sys_device *dev, int nid)
{
struct node *node = &node_devices[nid];
sysfs_remove_link(&node->sysdev.kobj, kobject_name(&dev->kobj));
}
EXPORT_SYMBOL_GPL(sysfs_remove_device_from_node);
#else
static void register_nodes(void)
{
return;
}
#endif
/* Only valid if CPU is present. */
static ssize_t show_physical_id(struct sys_device *dev,
struct sysdev_attribute *attr, char *buf)
{
struct cpu *cpu = container_of(dev, struct cpu, sysdev);
return sprintf(buf, "%d\n", get_hard_smp_processor_id(cpu->sysdev.id));
}
static SYSDEV_ATTR(physical_id, 0444, show_physical_id, NULL);
static int __init topology_init(void)
{
int cpu;
register_nodes();
register_cpu_notifier(&sysfs_cpu_nb);
for_each_possible_cpu(cpu) {
struct cpu *c = &per_cpu(cpu_devices, cpu);
/*
* For now, we just see if the system supports making
* the RTAS calls for CPU hotplug. But, there may be a
* more comprehensive way to do this for an individual
* CPU. For instance, the boot cpu might never be valid
* for hotplugging.
*/
if (ppc_md.cpu_die)
c->hotpluggable = 1;
if (cpu_online(cpu) || c->hotpluggable) {
register_cpu(c, cpu);
sysdev_create_file(&c->sysdev, &attr_physical_id);
}
if (cpu_online(cpu))
register_cpu_online(cpu);
}
return 0;
}
subsys_initcall(topology_init);
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