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linux-next/drivers/cpufreq/ia64-acpi-cpufreq.c
Thomas Gleixner 38f05ed04b cpufreq/ia64: Replace racy task affinity logic
The get() and target() callbacks must run on the affected cpu. This is
achieved by temporarily setting the affinity of the calling thread to the
requested CPU and reset it to the original affinity afterwards.

That's racy vs. concurrent affinity settings for that thread resulting in
code executing on the wrong CPU and overwriting the new affinity setting.

Replace it by work_on_cpu(). All call pathes which invoke the callbacks are
already protected against CPU hotplug.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: linux-pm@vger.kernel.org
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Tejun Heo <tj@kernel.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Len Brown <lenb@kernel.org>
Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1704122231100.2548@nanos
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2017-04-15 12:20:55 +02:00

363 lines
7.7 KiB
C

/*
* This file provides the ACPI based P-state support. This
* module works with generic cpufreq infrastructure. Most of
* the code is based on i386 version
* (arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c)
*
* Copyright (C) 2005 Intel Corp
* Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/cpufreq.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <asm/io.h>
#include <linux/uaccess.h>
#include <asm/pal.h>
#include <linux/acpi.h>
#include <acpi/processor.h>
MODULE_AUTHOR("Venkatesh Pallipadi");
MODULE_DESCRIPTION("ACPI Processor P-States Driver");
MODULE_LICENSE("GPL");
struct cpufreq_acpi_io {
struct acpi_processor_performance acpi_data;
unsigned int resume;
};
struct cpufreq_acpi_req {
unsigned int cpu;
unsigned int state;
};
static struct cpufreq_acpi_io *acpi_io_data[NR_CPUS];
static struct cpufreq_driver acpi_cpufreq_driver;
static int
processor_set_pstate (
u32 value)
{
s64 retval;
pr_debug("processor_set_pstate\n");
retval = ia64_pal_set_pstate((u64)value);
if (retval) {
pr_debug("Failed to set freq to 0x%x, with error 0x%lx\n",
value, retval);
return -ENODEV;
}
return (int)retval;
}
static int
processor_get_pstate (
u32 *value)
{
u64 pstate_index = 0;
s64 retval;
pr_debug("processor_get_pstate\n");
retval = ia64_pal_get_pstate(&pstate_index,
PAL_GET_PSTATE_TYPE_INSTANT);
*value = (u32) pstate_index;
if (retval)
pr_debug("Failed to get current freq with "
"error 0x%lx, idx 0x%x\n", retval, *value);
return (int)retval;
}
/* To be used only after data->acpi_data is initialized */
static unsigned
extract_clock (
struct cpufreq_acpi_io *data,
unsigned value)
{
unsigned long i;
pr_debug("extract_clock\n");
for (i = 0; i < data->acpi_data.state_count; i++) {
if (value == data->acpi_data.states[i].status)
return data->acpi_data.states[i].core_frequency;
}
return data->acpi_data.states[i-1].core_frequency;
}
static long
processor_get_freq (
void *arg)
{
struct cpufreq_acpi_req *req = arg;
unsigned int cpu = req->cpu;
struct cpufreq_acpi_io *data = acpi_io_data[cpu];
u32 value;
int ret;
pr_debug("processor_get_freq\n");
if (smp_processor_id() != cpu)
return -EAGAIN;
/* processor_get_pstate gets the instantaneous frequency */
ret = processor_get_pstate(&value);
if (ret) {
pr_warn("get performance failed with error %d\n", ret);
return ret;
}
return 1000 * extract_clock(data, value);
}
static long
processor_set_freq (
void *arg)
{
struct cpufreq_acpi_req *req = arg;
unsigned int cpu = req->cpu;
struct cpufreq_acpi_io *data = acpi_io_data[cpu];
int ret, state = req->state;
u32 value;
pr_debug("processor_set_freq\n");
if (smp_processor_id() != cpu)
return -EAGAIN;
if (state == data->acpi_data.state) {
if (unlikely(data->resume)) {
pr_debug("Called after resume, resetting to P%d\n", state);
data->resume = 0;
} else {
pr_debug("Already at target state (P%d)\n", state);
return 0;
}
}
pr_debug("Transitioning from P%d to P%d\n",
data->acpi_data.state, state);
/*
* First we write the target state's 'control' value to the
* control_register.
*/
value = (u32) data->acpi_data.states[state].control;
pr_debug("Transitioning to state: 0x%08x\n", value);
ret = processor_set_pstate(value);
if (ret) {
pr_warn("Transition failed with error %d\n", ret);
return -ENODEV;
}
data->acpi_data.state = state;
return 0;
}
static unsigned int
acpi_cpufreq_get (
unsigned int cpu)
{
struct cpufreq_acpi_req req;
long ret;
req.cpu = cpu;
ret = work_on_cpu(cpu, processor_get_freq, &req);
return ret > 0 ? (unsigned int) ret : 0;
}
static int
acpi_cpufreq_target (
struct cpufreq_policy *policy,
unsigned int index)
{
struct cpufreq_acpi_req req;
req.cpu = policy->cpu;
req.state = index;
return work_on_cpu(req.cpu, processor_set_freq, &req);
}
static int
acpi_cpufreq_cpu_init (
struct cpufreq_policy *policy)
{
unsigned int i;
unsigned int cpu = policy->cpu;
struct cpufreq_acpi_io *data;
unsigned int result = 0;
struct cpufreq_frequency_table *freq_table;
pr_debug("acpi_cpufreq_cpu_init\n");
data = kzalloc(sizeof(*data), GFP_KERNEL);
if (!data)
return (-ENOMEM);
acpi_io_data[cpu] = data;
result = acpi_processor_register_performance(&data->acpi_data, cpu);
if (result)
goto err_free;
/* capability check */
if (data->acpi_data.state_count <= 1) {
pr_debug("No P-States\n");
result = -ENODEV;
goto err_unreg;
}
if ((data->acpi_data.control_register.space_id !=
ACPI_ADR_SPACE_FIXED_HARDWARE) ||
(data->acpi_data.status_register.space_id !=
ACPI_ADR_SPACE_FIXED_HARDWARE)) {
pr_debug("Unsupported address space [%d, %d]\n",
(u32) (data->acpi_data.control_register.space_id),
(u32) (data->acpi_data.status_register.space_id));
result = -ENODEV;
goto err_unreg;
}
/* alloc freq_table */
freq_table = kzalloc(sizeof(*freq_table) *
(data->acpi_data.state_count + 1),
GFP_KERNEL);
if (!freq_table) {
result = -ENOMEM;
goto err_unreg;
}
/* detect transition latency */
policy->cpuinfo.transition_latency = 0;
for (i=0; i<data->acpi_data.state_count; i++) {
if ((data->acpi_data.states[i].transition_latency * 1000) >
policy->cpuinfo.transition_latency) {
policy->cpuinfo.transition_latency =
data->acpi_data.states[i].transition_latency * 1000;
}
}
/* table init */
for (i = 0; i <= data->acpi_data.state_count; i++)
{
if (i < data->acpi_data.state_count) {
freq_table[i].frequency =
data->acpi_data.states[i].core_frequency * 1000;
} else {
freq_table[i].frequency = CPUFREQ_TABLE_END;
}
}
result = cpufreq_table_validate_and_show(policy, freq_table);
if (result) {
goto err_freqfree;
}
/* notify BIOS that we exist */
acpi_processor_notify_smm(THIS_MODULE);
pr_info("CPU%u - ACPI performance management activated\n", cpu);
for (i = 0; i < data->acpi_data.state_count; i++)
pr_debug(" %cP%d: %d MHz, %d mW, %d uS, %d uS, 0x%x 0x%x\n",
(i == data->acpi_data.state?'*':' '), i,
(u32) data->acpi_data.states[i].core_frequency,
(u32) data->acpi_data.states[i].power,
(u32) data->acpi_data.states[i].transition_latency,
(u32) data->acpi_data.states[i].bus_master_latency,
(u32) data->acpi_data.states[i].status,
(u32) data->acpi_data.states[i].control);
/* the first call to ->target() should result in us actually
* writing something to the appropriate registers. */
data->resume = 1;
return (result);
err_freqfree:
kfree(freq_table);
err_unreg:
acpi_processor_unregister_performance(cpu);
err_free:
kfree(data);
acpi_io_data[cpu] = NULL;
return (result);
}
static int
acpi_cpufreq_cpu_exit (
struct cpufreq_policy *policy)
{
struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
pr_debug("acpi_cpufreq_cpu_exit\n");
if (data) {
acpi_io_data[policy->cpu] = NULL;
acpi_processor_unregister_performance(policy->cpu);
kfree(policy->freq_table);
kfree(data);
}
return (0);
}
static struct cpufreq_driver acpi_cpufreq_driver = {
.verify = cpufreq_generic_frequency_table_verify,
.target_index = acpi_cpufreq_target,
.get = acpi_cpufreq_get,
.init = acpi_cpufreq_cpu_init,
.exit = acpi_cpufreq_cpu_exit,
.name = "acpi-cpufreq",
.attr = cpufreq_generic_attr,
};
static int __init
acpi_cpufreq_init (void)
{
pr_debug("acpi_cpufreq_init\n");
return cpufreq_register_driver(&acpi_cpufreq_driver);
}
static void __exit
acpi_cpufreq_exit (void)
{
pr_debug("acpi_cpufreq_exit\n");
cpufreq_unregister_driver(&acpi_cpufreq_driver);
return;
}
late_initcall(acpi_cpufreq_init);
module_exit(acpi_cpufreq_exit);