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linux-pinenote/arch/sparc/kernel/sysfs.c
Srivatsa S. Bhat 1e0b0c4c6b sparc, sysfs: Fix CPU hotplug callback registration 
Subsystems that want to register CPU hotplug callbacks, as well as perform
initialization for the CPUs that are already online, often do it as shown
below:

	get_online_cpus();

	for_each_online_cpu(cpu)
		init_cpu(cpu);

	register_cpu_notifier(&foobar_cpu_notifier);

	put_online_cpus();

This is wrong, since it is prone to ABBA deadlocks involving the
cpu_add_remove_lock and the cpu_hotplug.lock (when running concurrently
with CPU hotplug operations).

Instead, the correct and race-free way of performing the callback
registration is:

	cpu_notifier_register_begin();

	for_each_online_cpu(cpu)
		init_cpu(cpu);

	/* Note the use of the double underscored version of the API */
	__register_cpu_notifier(&foobar_cpu_notifier);

	cpu_notifier_register_done();

Fix the sysfs code in sparc by using this latter form of callback
registration.

Cc: Ingo Molnar <mingo@kernel.org>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-03-20 13:43:41 +01:00

320 lines
8.8 KiB
C
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/* sysfs.c: Toplogy sysfs support code for sparc64.
*
* Copyright (C) 2007 David S. Miller <davem@davemloft.net>
*/
#include <linux/sched.h>
#include <linux/device.h>
#include <linux/cpu.h>
#include <linux/smp.h>
#include <linux/percpu.h>
#include <linux/init.h>
#include <asm/cpudata.h>
#include <asm/hypervisor.h>
#include <asm/spitfire.h>
static DEFINE_PER_CPU(struct hv_mmu_statistics, mmu_stats) __attribute__((aligned(64)));
#define SHOW_MMUSTAT_ULONG(NAME) \
static ssize_t show_##NAME(struct device *dev, \
struct device_attribute *attr, char *buf) \
{ \
struct hv_mmu_statistics *p = &per_cpu(mmu_stats, dev->id); \
return sprintf(buf, "%lu\n", p->NAME); \
} \
static DEVICE_ATTR(NAME, 0444, show_##NAME, NULL)
SHOW_MMUSTAT_ULONG(immu_tsb_hits_ctx0_8k_tte);
SHOW_MMUSTAT_ULONG(immu_tsb_ticks_ctx0_8k_tte);
SHOW_MMUSTAT_ULONG(immu_tsb_hits_ctx0_64k_tte);
SHOW_MMUSTAT_ULONG(immu_tsb_ticks_ctx0_64k_tte);
SHOW_MMUSTAT_ULONG(immu_tsb_hits_ctx0_4mb_tte);
SHOW_MMUSTAT_ULONG(immu_tsb_ticks_ctx0_4mb_tte);
SHOW_MMUSTAT_ULONG(immu_tsb_hits_ctx0_256mb_tte);
SHOW_MMUSTAT_ULONG(immu_tsb_ticks_ctx0_256mb_tte);
SHOW_MMUSTAT_ULONG(immu_tsb_hits_ctxnon0_8k_tte);
SHOW_MMUSTAT_ULONG(immu_tsb_ticks_ctxnon0_8k_tte);
SHOW_MMUSTAT_ULONG(immu_tsb_hits_ctxnon0_64k_tte);
SHOW_MMUSTAT_ULONG(immu_tsb_ticks_ctxnon0_64k_tte);
SHOW_MMUSTAT_ULONG(immu_tsb_hits_ctxnon0_4mb_tte);
SHOW_MMUSTAT_ULONG(immu_tsb_ticks_ctxnon0_4mb_tte);
SHOW_MMUSTAT_ULONG(immu_tsb_hits_ctxnon0_256mb_tte);
SHOW_MMUSTAT_ULONG(immu_tsb_ticks_ctxnon0_256mb_tte);
SHOW_MMUSTAT_ULONG(dmmu_tsb_hits_ctx0_8k_tte);
SHOW_MMUSTAT_ULONG(dmmu_tsb_ticks_ctx0_8k_tte);
SHOW_MMUSTAT_ULONG(dmmu_tsb_hits_ctx0_64k_tte);
SHOW_MMUSTAT_ULONG(dmmu_tsb_ticks_ctx0_64k_tte);
SHOW_MMUSTAT_ULONG(dmmu_tsb_hits_ctx0_4mb_tte);
SHOW_MMUSTAT_ULONG(dmmu_tsb_ticks_ctx0_4mb_tte);
SHOW_MMUSTAT_ULONG(dmmu_tsb_hits_ctx0_256mb_tte);
SHOW_MMUSTAT_ULONG(dmmu_tsb_ticks_ctx0_256mb_tte);
SHOW_MMUSTAT_ULONG(dmmu_tsb_hits_ctxnon0_8k_tte);
SHOW_MMUSTAT_ULONG(dmmu_tsb_ticks_ctxnon0_8k_tte);
SHOW_MMUSTAT_ULONG(dmmu_tsb_hits_ctxnon0_64k_tte);
SHOW_MMUSTAT_ULONG(dmmu_tsb_ticks_ctxnon0_64k_tte);
SHOW_MMUSTAT_ULONG(dmmu_tsb_hits_ctxnon0_4mb_tte);
SHOW_MMUSTAT_ULONG(dmmu_tsb_ticks_ctxnon0_4mb_tte);
SHOW_MMUSTAT_ULONG(dmmu_tsb_hits_ctxnon0_256mb_tte);
SHOW_MMUSTAT_ULONG(dmmu_tsb_ticks_ctxnon0_256mb_tte);
static struct attribute *mmu_stat_attrs[] = {
&dev_attr_immu_tsb_hits_ctx0_8k_tte.attr,
&dev_attr_immu_tsb_ticks_ctx0_8k_tte.attr,
&dev_attr_immu_tsb_hits_ctx0_64k_tte.attr,
&dev_attr_immu_tsb_ticks_ctx0_64k_tte.attr,
&dev_attr_immu_tsb_hits_ctx0_4mb_tte.attr,
&dev_attr_immu_tsb_ticks_ctx0_4mb_tte.attr,
&dev_attr_immu_tsb_hits_ctx0_256mb_tte.attr,
&dev_attr_immu_tsb_ticks_ctx0_256mb_tte.attr,
&dev_attr_immu_tsb_hits_ctxnon0_8k_tte.attr,
&dev_attr_immu_tsb_ticks_ctxnon0_8k_tte.attr,
&dev_attr_immu_tsb_hits_ctxnon0_64k_tte.attr,
&dev_attr_immu_tsb_ticks_ctxnon0_64k_tte.attr,
&dev_attr_immu_tsb_hits_ctxnon0_4mb_tte.attr,
&dev_attr_immu_tsb_ticks_ctxnon0_4mb_tte.attr,
&dev_attr_immu_tsb_hits_ctxnon0_256mb_tte.attr,
&dev_attr_immu_tsb_ticks_ctxnon0_256mb_tte.attr,
&dev_attr_dmmu_tsb_hits_ctx0_8k_tte.attr,
&dev_attr_dmmu_tsb_ticks_ctx0_8k_tte.attr,
&dev_attr_dmmu_tsb_hits_ctx0_64k_tte.attr,
&dev_attr_dmmu_tsb_ticks_ctx0_64k_tte.attr,
&dev_attr_dmmu_tsb_hits_ctx0_4mb_tte.attr,
&dev_attr_dmmu_tsb_ticks_ctx0_4mb_tte.attr,
&dev_attr_dmmu_tsb_hits_ctx0_256mb_tte.attr,
&dev_attr_dmmu_tsb_ticks_ctx0_256mb_tte.attr,
&dev_attr_dmmu_tsb_hits_ctxnon0_8k_tte.attr,
&dev_attr_dmmu_tsb_ticks_ctxnon0_8k_tte.attr,
&dev_attr_dmmu_tsb_hits_ctxnon0_64k_tte.attr,
&dev_attr_dmmu_tsb_ticks_ctxnon0_64k_tte.attr,
&dev_attr_dmmu_tsb_hits_ctxnon0_4mb_tte.attr,
&dev_attr_dmmu_tsb_ticks_ctxnon0_4mb_tte.attr,
&dev_attr_dmmu_tsb_hits_ctxnon0_256mb_tte.attr,
&dev_attr_dmmu_tsb_ticks_ctxnon0_256mb_tte.attr,
NULL,
};
static struct attribute_group mmu_stat_group = {
.attrs = mmu_stat_attrs,
.name = "mmu_stats",
};
/* XXX convert to rusty's on_one_cpu */
static unsigned long run_on_cpu(unsigned long cpu,
unsigned long (*func)(unsigned long),
unsigned long arg)
{
cpumask_t old_affinity;
unsigned long ret;
cpumask_copy(&old_affinity, tsk_cpus_allowed(current));
/* should return -EINVAL to userspace */
if (set_cpus_allowed_ptr(current, cpumask_of(cpu)))
return 0;
ret = func(arg);
set_cpus_allowed_ptr(current, &old_affinity);
return ret;
}
static unsigned long read_mmustat_enable(unsigned long junk)
{
unsigned long ra = 0;
sun4v_mmustat_info(&ra);
return ra != 0;
}
static unsigned long write_mmustat_enable(unsigned long val)
{
unsigned long ra, orig_ra;
if (val)
ra = __pa(&per_cpu(mmu_stats, smp_processor_id()));
else
ra = 0UL;
return sun4v_mmustat_conf(ra, &orig_ra);
}
static ssize_t show_mmustat_enable(struct device *s,
struct device_attribute *attr, char *buf)
{
unsigned long val = run_on_cpu(s->id, read_mmustat_enable, 0);
return sprintf(buf, "%lx\n", val);
}
static ssize_t store_mmustat_enable(struct device *s,
struct device_attribute *attr, const char *buf,
size_t count)
{
unsigned long val, err;
int ret = sscanf(buf, "%ld", &val);
if (ret != 1)
return -EINVAL;
err = run_on_cpu(s->id, write_mmustat_enable, val);
if (err)
return -EIO;
return count;
}
static DEVICE_ATTR(mmustat_enable, 0644, show_mmustat_enable, store_mmustat_enable);
static int mmu_stats_supported;
static int register_mmu_stats(struct device *s)
{
if (!mmu_stats_supported)
return 0;
device_create_file(s, &dev_attr_mmustat_enable);
return sysfs_create_group(&s->kobj, &mmu_stat_group);
}
#ifdef CONFIG_HOTPLUG_CPU
static void unregister_mmu_stats(struct device *s)
{
if (!mmu_stats_supported)
return;
sysfs_remove_group(&s->kobj, &mmu_stat_group);
device_remove_file(s, &dev_attr_mmustat_enable);
}
#endif
#define SHOW_CPUDATA_ULONG_NAME(NAME, MEMBER) \
static ssize_t show_##NAME(struct device *dev, \
struct device_attribute *attr, char *buf) \
{ \
cpuinfo_sparc *c = &cpu_data(dev->id); \
return sprintf(buf, "%lu\n", c->MEMBER); \
}
#define SHOW_CPUDATA_UINT_NAME(NAME, MEMBER) \
static ssize_t show_##NAME(struct device *dev, \
struct device_attribute *attr, char *buf) \
{ \
cpuinfo_sparc *c = &cpu_data(dev->id); \
return sprintf(buf, "%u\n", c->MEMBER); \
}
SHOW_CPUDATA_ULONG_NAME(clock_tick, clock_tick);
SHOW_CPUDATA_UINT_NAME(l1_dcache_size, dcache_size);
SHOW_CPUDATA_UINT_NAME(l1_dcache_line_size, dcache_line_size);
SHOW_CPUDATA_UINT_NAME(l1_icache_size, icache_size);
SHOW_CPUDATA_UINT_NAME(l1_icache_line_size, icache_line_size);
SHOW_CPUDATA_UINT_NAME(l2_cache_size, ecache_size);
SHOW_CPUDATA_UINT_NAME(l2_cache_line_size, ecache_line_size);
static struct device_attribute cpu_core_attrs[] = {
__ATTR(clock_tick, 0444, show_clock_tick, NULL),
__ATTR(l1_dcache_size, 0444, show_l1_dcache_size, NULL),
__ATTR(l1_dcache_line_size, 0444, show_l1_dcache_line_size, NULL),
__ATTR(l1_icache_size, 0444, show_l1_icache_size, NULL),
__ATTR(l1_icache_line_size, 0444, show_l1_icache_line_size, NULL),
__ATTR(l2_cache_size, 0444, show_l2_cache_size, NULL),
__ATTR(l2_cache_line_size, 0444, show_l2_cache_line_size, NULL),
};
static DEFINE_PER_CPU(struct cpu, cpu_devices);
static void register_cpu_online(unsigned int cpu)
{
struct cpu *c = &per_cpu(cpu_devices, cpu);
struct device *s = &c->dev;
int i;
for (i = 0; i < ARRAY_SIZE(cpu_core_attrs); i++)
device_create_file(s, &cpu_core_attrs[i]);
register_mmu_stats(s);
}
#ifdef CONFIG_HOTPLUG_CPU
static void unregister_cpu_online(unsigned int cpu)
{
struct cpu *c = &per_cpu(cpu_devices, cpu);
struct device *s = &c->dev;
int i;
unregister_mmu_stats(s);
for (i = 0; i < ARRAY_SIZE(cpu_core_attrs); i++)
device_remove_file(s, &cpu_core_attrs[i]);
}
#endif
static int 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 sysfs_cpu_nb = {
.notifier_call = sysfs_cpu_notify,
};
static void __init check_mmu_stats(void)
{
unsigned long dummy1, err;
if (tlb_type != hypervisor)
return;
err = sun4v_mmustat_info(&dummy1);
if (!err)
mmu_stats_supported = 1;
}
static void register_nodes(void)
{
#ifdef CONFIG_NUMA
int i;
for (i = 0; i < MAX_NUMNODES; i++)
register_one_node(i);
#endif
}
static int __init topology_init(void)
{
int cpu;
register_nodes();
check_mmu_stats();
cpu_notifier_register_begin();
for_each_possible_cpu(cpu) {
struct cpu *c = &per_cpu(cpu_devices, cpu);
register_cpu(c, cpu);
if (cpu_online(cpu))
register_cpu_online(cpu);
}
__register_cpu_notifier(&sysfs_cpu_nb);
cpu_notifier_register_done();
return 0;
}
subsys_initcall(topology_init);
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