path: root/arch/powerpc/kernel/sysfs.c

// SPDX-License-Identifier: GPL-2.0-only
#include <linux/device.h>
#include <linux/cpu.h>
#include <linux/smp.h>
#include <linux/percpu.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/export.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/hvcall.h>
#include <asm/prom.h>
#include <asm/machdep.h>
#include <asm/smp.h>
#include <asm/pmc.h>
#include <asm/firmware.h>
#include <asm/idle.h>
#include <asm/svm.h>

#include "cacheinfo.h"
#include "setup.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 */
static DEFINE_PER_CPU(long, smt_snooze_delay) = { 100 };

static ssize_t store_smt_snooze_delay(struct device *dev,
				      struct device_attribute *attr,
				      const char *buf,
				      size_t count)
{
	struct cpu *cpu = container_of(dev, struct cpu, dev);
	ssize_t ret;
	long snooze;

	ret = sscanf(buf, "%ld", &snooze);
	if (ret != 1)
		return -EINVAL;

	per_cpu(smt_snooze_delay, cpu->dev.id) = snooze;
	return count;
}

static ssize_t show_smt_snooze_delay(struct device *dev,
				     struct device_attribute *attr,
				     char *buf)
{
	struct cpu *cpu = container_of(dev, struct cpu, dev);

	return sprintf(buf, "%ld\n", per_cpu(smt_snooze_delay, cpu->dev.id));
}

static DEVICE_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 */

#define __SYSFS_SPRSETUP_READ_WRITE(NAME, ADDRESS, EXTRA) \
static void read_##NAME(void *val) \
{ \
	*(unsigned long *)val = mfspr(ADDRESS);	\
} \
static void write_##NAME(void *val) \
{ \
	EXTRA; \
	mtspr(ADDRESS, *(unsigned long *)val);	\
}

#define __SYSFS_SPRSETUP_SHOW_STORE(NAME) \
static ssize_t show_##NAME(struct device *dev, \
			struct device_attribute *attr, \
			char *buf) \
{ \
	struct cpu *cpu = container_of(dev, struct cpu, dev); \
	unsigned long val; \
	smp_call_function_single(cpu->dev.id, read_##NAME, &val, 1);	\
	return sprintf(buf, "%lx\n", val); \
} \
static ssize_t __used \
	store_##NAME(struct device *dev, struct device_attribute *attr, \
			const char *buf, size_t count) \
{ \
	struct cpu *cpu = container_of(dev, struct cpu, dev); \
	unsigned long val; \
	int ret = sscanf(buf, "%lx", &val); \
	if (ret != 1) \
		return -EINVAL; \
	smp_call_function_single(cpu->dev.id, write_##NAME, &val, 1); \
	return count; \
}

#define SYSFS_PMCSETUP(NAME, ADDRESS) \
	__SYSFS_SPRSETUP_READ_WRITE(NAME, ADDRESS, ppc_enable_pmcs()) \
	__SYSFS_SPRSETUP_SHOW_STORE(NAME)
#define SYSFS_SPRSETUP(NAME, ADDRESS) \
	__SYSFS_SPRSETUP_READ_WRITE(NAME, ADDRESS, ) \
	__SYSFS_SPRSETUP_SHOW_STORE(NAME)

#define SYSFS_SPRSETUP_SHOW_STORE(NAME) \
	__SYSFS_SPRSETUP_SHOW_STORE(NAME)

#ifdef CONFIG_PPC64

/*
 * This is the system wide DSCR register default value. Any
 * change to this default value through the sysfs interface
 * will update all per cpu DSCR default values across the
 * system stored in their respective PACA structures.
 */
static unsigned long dscr_default;

/**
 * read_dscr() - Fetch the cpu specific DSCR default
 * @val:	Returned cpu specific DSCR default value
 *