linux/drivers/acpi/processor_throttling.c
Thomas Gleixner 0266d81e9b acpi/processor: Prevent cpu hotplug deadlock
With the enhanced CPU hotplug lockdep coverage the following lockdep splat
happens:

======================================================
WARNING: possible circular locking dependency detected
4.12.0-rc2+ #84 Tainted: G        W      
------------------------------------------------------
cpuhp/1/15 is trying to acquire lock:
flush_work+0x39/0x2f0

but task is already holding lock:
cpuhp_thread_fun+0x30/0x160

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #2 (cpuhp_state){+.+.+.}:
       lock_acquire+0xb4/0x200
       cpuhp_kick_ap_work+0x72/0x330
       _cpu_down+0x8b/0x100
       do_cpu_down+0x3e/0x60
       cpu_down+0x10/0x20
       cpu_subsys_offline+0x14/0x20
       device_offline+0x88/0xb0
       online_store+0x4c/0xa0
       dev_attr_store+0x18/0x30
       sysfs_kf_write+0x45/0x60
       kernfs_fop_write+0x156/0x1e0
       __vfs_write+0x37/0x160
       vfs_write+0xca/0x1c0
       SyS_write+0x58/0xc0
       entry_SYSCALL_64_fastpath+0x23/0xc2

-> #1 (cpu_hotplug_lock.rw_sem){++++++}:
       lock_acquire+0xb4/0x200
       cpus_read_lock+0x3d/0xb0
       apply_workqueue_attrs+0x17/0x50
       __alloc_workqueue_key+0x1e1/0x530
       scsi_host_alloc+0x373/0x480 [scsi_mod]
       ata_scsi_add_hosts+0xcb/0x130 [libata]
       ata_host_register+0x11a/0x2c0 [libata]
       ata_host_activate+0xf0/0x150 [libata]
       ahci_host_activate+0x13e/0x170 [libahci]
       ahci_init_one+0xa3a/0xd3f [ahci]
       local_pci_probe+0x45/0xa0
       work_for_cpu_fn+0x14/0x20
       process_one_work+0x1f9/0x690
       worker_thread+0x200/0x3d0
       kthread+0x138/0x170
       ret_from_fork+0x31/0x40

-> #0 ((&wfc.work)){+.+.+.}:
       __lock_acquire+0x11e1/0x13e0
       lock_acquire+0xb4/0x200
       flush_work+0x5c/0x2f0
       work_on_cpu+0xa1/0xd0
       acpi_processor_get_throttling+0x3d/0x50
       acpi_processor_reevaluate_tstate+0x2c/0x50
       acpi_soft_cpu_online+0x69/0xd0
       cpuhp_invoke_callback+0xb4/0x8b0
       cpuhp_up_callbacks+0x36/0xc0
       cpuhp_thread_fun+0x14e/0x160
       smpboot_thread_fn+0x1e8/0x300
       kthread+0x138/0x170
       ret_from_fork+0x31/0x40

other info that might help us debug this:

Chain exists of:
  (&wfc.work) --> cpu_hotplug_lock.rw_sem --> cpuhp_state

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(cpuhp_state);
                               lock(cpu_hotplug_lock.rw_sem);
                               lock(cpuhp_state);
  lock((&wfc.work));

 *** DEADLOCK ***

1 lock held by cpuhp/1/15:
cpuhp_thread_fun+0x30/0x160

stack backtrace:
CPU: 1 PID: 15 Comm: cpuhp/1 Tainted: G        W       4.12.0-rc2+ #84
Hardware name: Supermicro SYS-4048B-TR4FT/X10QBi, BIOS 1.1a 07/29/2015
Call Trace:
 dump_stack+0x85/0xc4
 print_circular_bug+0x209/0x217
 __lock_acquire+0x11e1/0x13e0
 lock_acquire+0xb4/0x200
 ? lock_acquire+0xb4/0x200
 ? flush_work+0x39/0x2f0
 ? acpi_processor_start+0x50/0x50
 flush_work+0x5c/0x2f0
 ? flush_work+0x39/0x2f0
 ? acpi_processor_start+0x50/0x50
 ? mark_held_locks+0x6d/0x90
 ? queue_work_on+0x56/0x90
 ? trace_hardirqs_on_caller+0x154/0x1c0
 ? trace_hardirqs_on+0xd/0x10
 ? acpi_processor_start+0x50/0x50
 work_on_cpu+0xa1/0xd0
 ? find_worker_executing_work+0x50/0x50
 ? acpi_processor_power_exit+0x70/0x70
 acpi_processor_get_throttling+0x3d/0x50
 acpi_processor_reevaluate_tstate+0x2c/0x50
 acpi_soft_cpu_online+0x69/0xd0
 cpuhp_invoke_callback+0xb4/0x8b0
 ? lock_acquire+0xb4/0x200
 ? padata_replace+0x120/0x120
 cpuhp_up_callbacks+0x36/0xc0
 cpuhp_thread_fun+0x14e/0x160
 smpboot_thread_fn+0x1e8/0x300
 kthread+0x138/0x170
 ? sort_range+0x30/0x30
 ? kthread_create_on_node+0x70/0x70
 ret_from_fork+0x31/0x40

The problem is that the work is scheduled on the current CPU from the
hotplug thread associated with that CPU.

It's not required to invoke these functions via the workqueue because the
hotplug thread runs on the target CPU already.

Check whether current is a per cpu thread pinned on the target CPU and
invoke the function directly to avoid the workqueue.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-acpi@vger.kernel.org
Cc: Len Brown <lenb@kernel.org>
Link: http://lkml.kernel.org/r/20170524081549.620489733@linutronix.de
2017-05-26 10:10:47 +02:00

1280 lines
32 KiB
C

/*
* processor_throttling.c - Throttling submodule of the ACPI processor driver
*
* Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
* Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
* Copyright (C) 2004 Dominik Brodowski <linux@brodo.de>
* Copyright (C) 2004 Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
* - Added processor hotplug support
*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*
* 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.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/cpufreq.h>
#include <linux/acpi.h>
#include <acpi/processor.h>
#include <asm/io.h>
#include <linux/uaccess.h>
#define PREFIX "ACPI: "
#define ACPI_PROCESSOR_CLASS "processor"
#define _COMPONENT ACPI_PROCESSOR_COMPONENT
ACPI_MODULE_NAME("processor_throttling");
/* ignore_tpc:
* 0 -> acpi processor driver doesn't ignore _TPC values
* 1 -> acpi processor driver ignores _TPC values
*/
static int ignore_tpc;
module_param(ignore_tpc, int, 0644);
MODULE_PARM_DESC(ignore_tpc, "Disable broken BIOS _TPC throttling support");
struct throttling_tstate {
unsigned int cpu; /* cpu nr */
int target_state; /* target T-state */
};
struct acpi_processor_throttling_arg {
struct acpi_processor *pr;
int target_state;
bool force;
};
#define THROTTLING_PRECHANGE (1)
#define THROTTLING_POSTCHANGE (2)
static int acpi_processor_get_throttling(struct acpi_processor *pr);
static int __acpi_processor_set_throttling(struct acpi_processor *pr,
int state, bool force, bool direct);
static int acpi_processor_update_tsd_coord(void)
{
int count, count_target;
int retval = 0;
unsigned int i, j;
cpumask_var_t covered_cpus;
struct acpi_processor *pr, *match_pr;
struct acpi_tsd_package *pdomain, *match_pdomain;
struct acpi_processor_throttling *pthrottling, *match_pthrottling;
if (!zalloc_cpumask_var(&covered_cpus, GFP_KERNEL))
return -ENOMEM;
/*
* Now that we have _TSD data from all CPUs, lets setup T-state
* coordination between all CPUs.
*/
for_each_possible_cpu(i) {
pr = per_cpu(processors, i);
if (!pr)
continue;
/* Basic validity check for domain info */
pthrottling = &(pr->throttling);
/*
* If tsd package for one cpu is invalid, the coordination
* among all CPUs is thought as invalid.
* Maybe it is ugly.
*/
if (!pthrottling->tsd_valid_flag) {
retval = -EINVAL;
break;
}
}
if (retval)
goto err_ret;
for_each_possible_cpu(i) {
pr = per_cpu(processors, i);
if (!pr)
continue;
if (cpumask_test_cpu(i, covered_cpus))
continue;
pthrottling = &pr->throttling;
pdomain = &(pthrottling->domain_info);
cpumask_set_cpu(i, pthrottling->shared_cpu_map);
cpumask_set_cpu(i, covered_cpus);
/*
* If the number of processor in the TSD domain is 1, it is
* unnecessary to parse the coordination for this CPU.
*/
if (pdomain->num_processors <= 1)
continue;
/* Validate the Domain info */
count_target = pdomain->num_processors;
count = 1;
for_each_possible_cpu(j) {
if (i == j)
continue;
match_pr = per_cpu(processors, j);
if (!match_pr)
continue;
match_pthrottling = &(match_pr->throttling);
match_pdomain = &(match_pthrottling->domain_info);
if (match_pdomain->domain != pdomain->domain)
continue;
/* Here i and j are in the same domain.
* If two TSD packages have the same domain, they
* should have the same num_porcessors and
* coordination type. Otherwise it will be regarded
* as illegal.
*/
if (match_pdomain->num_processors != count_target) {
retval = -EINVAL;
goto err_ret;
}
if (pdomain->coord_type != match_pdomain->coord_type) {
retval = -EINVAL;
goto err_ret;
}
cpumask_set_cpu(j, covered_cpus);
cpumask_set_cpu(j, pthrottling->shared_cpu_map);
count++;
}
for_each_possible_cpu(j) {
if (i == j)
continue;
match_pr = per_cpu(processors, j);
if (!match_pr)
continue;
match_pthrottling = &(match_pr->throttling);
match_pdomain = &(match_pthrottling->domain_info);
if (match_pdomain->domain != pdomain->domain)
continue;
/*
* If some CPUS have the same domain, they
* will have the same shared_cpu_map.
*/
cpumask_copy(match_pthrottling->shared_cpu_map,
pthrottling->shared_cpu_map);
}
}
err_ret:
free_cpumask_var(covered_cpus);
for_each_possible_cpu(i) {
pr = per_cpu(processors, i);
if (!pr)
continue;
/*
* Assume no coordination on any error parsing domain info.
* The coordination type will be forced as SW_ALL.
*/
if (retval) {
pthrottling = &(pr->throttling);
cpumask_clear(pthrottling->shared_cpu_map);
cpumask_set_cpu(i, pthrottling->shared_cpu_map);
pthrottling->shared_type = DOMAIN_COORD_TYPE_SW_ALL;
}
}
return retval;
}
/*
* Update the T-state coordination after the _TSD
* data for all cpus is obtained.
*/
void acpi_processor_throttling_init(void)
{
if (acpi_processor_update_tsd_coord()) {
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"Assume no T-state coordination\n"));
}
return;
}
static int acpi_processor_throttling_notifier(unsigned long event, void *data)
{
struct throttling_tstate *p_tstate = data;
struct acpi_processor *pr;
unsigned int cpu ;
int target_state;
struct acpi_processor_limit *p_limit;
struct acpi_processor_throttling *p_throttling;
cpu = p_tstate->cpu;
pr = per_cpu(processors, cpu);
if (!pr) {
ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Invalid pr pointer\n"));
return 0;
}
if (!pr->flags.throttling) {
ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Throttling control is "
"unsupported on CPU %d\n", cpu));
return 0;
}
target_state = p_tstate->target_state;
p_throttling = &(pr->throttling);
switch (event) {
case THROTTLING_PRECHANGE:
/*
* Prechange event is used to choose one proper t-state,
* which meets the limits of thermal, user and _TPC.
*/
p_limit = &pr->limit;
if (p_limit->thermal.tx > target_state)
target_state = p_limit->thermal.tx;
if (p_limit->user.tx > target_state)
target_state = p_limit->user.tx;
if (pr->throttling_platform_limit > target_state)
target_state = pr->throttling_platform_limit;
if (target_state >= p_throttling->state_count) {
printk(KERN_WARNING
"Exceed the limit of T-state \n");
target_state = p_throttling->state_count - 1;
}
p_tstate->target_state = target_state;
ACPI_DEBUG_PRINT((ACPI_DB_INFO, "PreChange Event:"
"target T-state of CPU %d is T%d\n",
cpu, target_state));
break;
case THROTTLING_POSTCHANGE:
/*
* Postchange event is only used to update the
* T-state flag of acpi_processor_throttling.
*/
p_throttling->state = target_state;
ACPI_DEBUG_PRINT((ACPI_DB_INFO, "PostChange Event:"
"CPU %d is switched to T%d\n",
cpu, target_state));
break;
default:
printk(KERN_WARNING
"Unsupported Throttling notifier event\n");
break;
}
return 0;
}
/*
* _TPC - Throttling Present Capabilities
*/
static int acpi_processor_get_platform_limit(struct acpi_processor *pr)
{
acpi_status status = 0;
unsigned long long tpc = 0;
if (!pr)
return -EINVAL;
if (ignore_tpc)
goto end;
status = acpi_evaluate_integer(pr->handle, "_TPC", NULL, &tpc);
if (ACPI_FAILURE(status)) {
if (status != AE_NOT_FOUND) {
ACPI_EXCEPTION((AE_INFO, status, "Evaluating _TPC"));
}
return -ENODEV;
}
end:
pr->throttling_platform_limit = (int)tpc;
return 0;
}
int acpi_processor_tstate_has_changed(struct acpi_processor *pr)
{
int result = 0;
int throttling_limit;
int current_state;
struct acpi_processor_limit *limit;
int target_state;
if (ignore_tpc)
return 0;
result = acpi_processor_get_platform_limit(pr);
if (result) {
/* Throttling Limit is unsupported */
return result;
}
throttling_limit = pr->throttling_platform_limit;
if (throttling_limit >= pr->throttling.state_count) {
/* Uncorrect Throttling Limit */
return -EINVAL;
}
current_state = pr->throttling.state;
if (current_state > throttling_limit) {
/*
* The current state can meet the requirement of
* _TPC limit. But it is reasonable that OSPM changes
* t-states from high to low for better performance.
* Of course the limit condition of thermal
* and user should be considered.
*/
limit = &pr->limit;
target_state = throttling_limit;
if (limit->thermal.tx > target_state)
target_state = limit->thermal.tx;
if (limit->user.tx > target_state)
target_state = limit->user.tx;
} else if (current_state == throttling_limit) {
/*
* Unnecessary to change the throttling state
*/
return 0;
} else {
/*
* If the current state is lower than the limit of _TPC, it
* will be forced to switch to the throttling state defined
* by throttling_platfor_limit.
* Because the previous state meets with the limit condition
* of thermal and user, it is unnecessary to check it again.
*/
target_state = throttling_limit;
}
return acpi_processor_set_throttling(pr, target_state, false);
}
/*
* This function is used to reevaluate whether the T-state is valid
* after one CPU is onlined/offlined.
* It is noted that it won't reevaluate the following properties for
* the T-state.
* 1. Control method.
* 2. the number of supported T-state
* 3. TSD domain
*/
void acpi_processor_reevaluate_tstate(struct acpi_processor *pr,
bool is_dead)
{
int result = 0;
if (is_dead) {
/* When one CPU is offline, the T-state throttling
* will be invalidated.
*/
pr->flags.throttling = 0;
return;
}
/* the following is to recheck whether the T-state is valid for
* the online CPU
*/
if (!pr->throttling.state_count) {
/* If the number of T-state is invalid, it is
* invalidated.
*/
pr->flags.throttling = 0;
return;
}
pr->flags.throttling = 1;
/* Disable throttling (if enabled). We'll let subsequent
* policy (e.g.thermal) decide to lower performance if it
* so chooses, but for now we'll crank up the speed.
*/
result = acpi_processor_get_throttling(pr);
if (result)
goto end;
if (pr->throttling.state) {
result = acpi_processor_set_throttling(pr, 0, false);
if (result)
goto end;
}
end:
if (result)
pr->flags.throttling = 0;
}
/*
* _PTC - Processor Throttling Control (and status) register location
*/
static int acpi_processor_get_throttling_control(struct acpi_processor *pr)
{
int result = 0;
acpi_status status = 0;
struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
union acpi_object *ptc = NULL;
union acpi_object obj = { 0 };
struct acpi_processor_throttling *throttling;
status = acpi_evaluate_object(pr->handle, "_PTC", NULL, &buffer);
if (ACPI_FAILURE(status)) {
if (status != AE_NOT_FOUND) {
ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PTC"));
}
return -ENODEV;
}
ptc = (union acpi_object *)buffer.pointer;
if (!ptc || (ptc->type != ACPI_TYPE_PACKAGE)
|| (ptc->package.count != 2)) {
printk(KERN_ERR PREFIX "Invalid _PTC data\n");
result = -EFAULT;
goto end;
}
/*
* control_register
*/
obj = ptc->package.elements[0];
if ((obj.type != ACPI_TYPE_BUFFER)
|| (obj.buffer.length < sizeof(struct acpi_ptc_register))
|| (obj.buffer.pointer == NULL)) {
printk(KERN_ERR PREFIX
"Invalid _PTC data (control_register)\n");
result = -EFAULT;
goto end;
}
memcpy(&pr->throttling.control_register, obj.buffer.pointer,
sizeof(struct acpi_ptc_register));
/*
* status_register
*/
obj = ptc->package.elements[1];
if ((obj.type != ACPI_TYPE_BUFFER)
|| (obj.buffer.length < sizeof(struct acpi_ptc_register))
|| (obj.buffer.pointer == NULL)) {
printk(KERN_ERR PREFIX "Invalid _PTC data (status_register)\n");
result = -EFAULT;
goto end;
}
memcpy(&pr->throttling.status_register, obj.buffer.pointer,
sizeof(struct acpi_ptc_register));
throttling = &pr->throttling;
if ((throttling->control_register.bit_width +
throttling->control_register.bit_offset) > 32) {
printk(KERN_ERR PREFIX "Invalid _PTC control register\n");
result = -EFAULT;
goto end;
}
if ((throttling->status_register.bit_width +
throttling->status_register.bit_offset) > 32) {
printk(KERN_ERR PREFIX "Invalid _PTC status register\n");
result = -EFAULT;
goto end;
}
end:
kfree(buffer.pointer);
return result;
}
/*
* _TSS - Throttling Supported States
*/
static int acpi_processor_get_throttling_states(struct acpi_processor *pr)
{
int result = 0;
acpi_status status = AE_OK;
struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
struct acpi_buffer format = { sizeof("NNNNN"), "NNNNN" };
struct acpi_buffer state = { 0, NULL };
union acpi_object *tss = NULL;
int i;
status = acpi_evaluate_object(pr->handle, "_TSS", NULL, &buffer);
if (ACPI_FAILURE(status)) {
if (status != AE_NOT_FOUND) {
ACPI_EXCEPTION((AE_INFO, status, "Evaluating _TSS"));
}
return -ENODEV;
}
tss = buffer.pointer;
if (!tss || (tss->type != ACPI_TYPE_PACKAGE)) {
printk(KERN_ERR PREFIX "Invalid _TSS data\n");
result = -EFAULT;
goto end;
}
ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d throttling states\n",
tss->package.count));
pr->throttling.state_count = tss->package.count;
pr->throttling.states_tss =
kmalloc(sizeof(struct acpi_processor_tx_tss) * tss->package.count,
GFP_KERNEL);
if (!pr->throttling.states_tss) {
result = -ENOMEM;
goto end;
}
for (i = 0; i < pr->throttling.state_count; i++) {
struct acpi_processor_tx_tss *tx =
(struct acpi_processor_tx_tss *)&(pr->throttling.
states_tss[i]);
state.length = sizeof(struct acpi_processor_tx_tss);
state.pointer = tx;
ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Extracting state %d\n", i));
status = acpi_extract_package(&(tss->package.elements[i]),
&format, &state);
if (ACPI_FAILURE(status)) {
ACPI_EXCEPTION((AE_INFO, status, "Invalid _TSS data"));
result = -EFAULT;
kfree(pr->throttling.states_tss);
goto end;
}
if (!tx->freqpercentage) {
printk(KERN_ERR PREFIX
"Invalid _TSS data: freq is zero\n");
result = -EFAULT;
kfree(pr->throttling.states_tss);
goto end;
}
}
end:
kfree(buffer.pointer);
return result;
}
/*
* _TSD - T-State Dependencies
*/
static int acpi_processor_get_tsd(struct acpi_processor *pr)
{
int result = 0;
acpi_status status = AE_OK;
struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
struct acpi_buffer format = { sizeof("NNNNN"), "NNNNN" };
struct acpi_buffer state = { 0, NULL };
union acpi_object *tsd = NULL;
struct acpi_tsd_package *pdomain;
struct acpi_processor_throttling *pthrottling;
pthrottling = &pr->throttling;
pthrottling->tsd_valid_flag = 0;
status = acpi_evaluate_object(pr->handle, "_TSD", NULL, &buffer);
if (ACPI_FAILURE(status)) {
if (status != AE_NOT_FOUND) {
ACPI_EXCEPTION((AE_INFO, status, "Evaluating _TSD"));
}
return -ENODEV;
}
tsd = buffer.pointer;
if (!tsd || (tsd->type != ACPI_TYPE_PACKAGE)) {
printk(KERN_ERR PREFIX "Invalid _TSD data\n");
result = -EFAULT;
goto end;
}
if (tsd->package.count != 1) {
printk(KERN_ERR PREFIX "Invalid _TSD data\n");
result = -EFAULT;
goto end;
}
pdomain = &(pr->throttling.domain_info);
state.length = sizeof(struct acpi_tsd_package);
state.pointer = pdomain;
status = acpi_extract_package(&(tsd->package.elements[0]),
&format, &state);
if (ACPI_FAILURE(status)) {
printk(KERN_ERR PREFIX "Invalid _TSD data\n");
result = -EFAULT;
goto end;
}
if (pdomain->num_entries != ACPI_TSD_REV0_ENTRIES) {
printk(KERN_ERR PREFIX "Unknown _TSD:num_entries\n");
result = -EFAULT;
goto end;
}
if (pdomain->revision != ACPI_TSD_REV0_REVISION) {
printk(KERN_ERR PREFIX "Unknown _TSD:revision\n");
result = -EFAULT;
goto end;
}
pthrottling = &pr->throttling;
pthrottling->tsd_valid_flag = 1;
pthrottling->shared_type = pdomain->coord_type;
cpumask_set_cpu(pr->id, pthrottling->shared_cpu_map);
/*
* If the coordination type is not defined in ACPI spec,
* the tsd_valid_flag will be clear and coordination type
* will be forecd as DOMAIN_COORD_TYPE_SW_ALL.
*/
if (pdomain->coord_type != DOMAIN_COORD_TYPE_SW_ALL &&
pdomain->coord_type != DOMAIN_COORD_TYPE_SW_ANY &&
pdomain->coord_type != DOMAIN_COORD_TYPE_HW_ALL) {
pthrottling->tsd_valid_flag = 0;
pthrottling->shared_type = DOMAIN_COORD_TYPE_SW_ALL;
}
end:
kfree(buffer.pointer);
return result;
}
/* --------------------------------------------------------------------------
Throttling Control
-------------------------------------------------------------------------- */
static int acpi_processor_get_throttling_fadt(struct acpi_processor *pr)
{
int state = 0;
u32 value = 0;
u32 duty_mask = 0;
u32 duty_value = 0;
if (!pr)
return -EINVAL;
if (!pr->flags.throttling)
return -ENODEV;
/*
* We don't care about error returns - we just try to mark
* these reserved so that nobody else is confused into thinking
* that this region might be unused..
*
* (In particular, allocating the IO range for Cardbus)
*/
request_region(pr->throttling.address, 6, "ACPI CPU throttle");
pr->throttling.state = 0;
duty_mask = pr->throttling.state_count - 1;
duty_mask <<= pr->throttling.duty_offset;
local_irq_disable();
value = inl(pr->throttling.address);
/*
* Compute the current throttling state when throttling is enabled
* (bit 4 is on).
*/
if (value & 0x10) {
duty_value = value & duty_mask;
duty_value >>= pr->throttling.duty_offset;
if (duty_value)
state = pr->throttling.state_count - duty_value;
}
pr->throttling.state = state;
local_irq_enable();
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"Throttling state is T%d (%d%% throttling applied)\n",
state, pr->throttling.states[state].performance));
return 0;
}
#ifdef CONFIG_X86
static int acpi_throttling_rdmsr(u64 *value)
{
u64 msr_high, msr_low;
u64 msr = 0;
int ret = -1;
if ((this_cpu_read(cpu_info.x86_vendor) != X86_VENDOR_INTEL) ||
!this_cpu_has(X86_FEATURE_ACPI)) {
printk(KERN_ERR PREFIX
"HARDWARE addr space,NOT supported yet\n");
} else {
msr_low = 0;
msr_high = 0;
rdmsr_safe(MSR_IA32_THERM_CONTROL,
(u32 *)&msr_low , (u32 *) &msr_high);
msr = (msr_high << 32) | msr_low;
*value = (u64) msr;
ret = 0;
}
return ret;
}
static int acpi_throttling_wrmsr(u64 value)
{
int ret = -1;
u64 msr;
if ((this_cpu_read(cpu_info.x86_vendor) != X86_VENDOR_INTEL) ||
!this_cpu_has(X86_FEATURE_ACPI)) {
printk(KERN_ERR PREFIX
"HARDWARE addr space,NOT supported yet\n");
} else {
msr = value;
wrmsr_safe(MSR_IA32_THERM_CONTROL,
msr & 0xffffffff, msr >> 32);
ret = 0;
}
return ret;
}
#else
static int acpi_throttling_rdmsr(u64 *value)
{
printk(KERN_ERR PREFIX
"HARDWARE addr space,NOT supported yet\n");
return -1;
}
static int acpi_throttling_wrmsr(u64 value)
{
printk(KERN_ERR PREFIX
"HARDWARE addr space,NOT supported yet\n");
return -1;
}
#endif
static int acpi_read_throttling_status(struct acpi_processor *pr,
u64 *value)
{
u32 bit_width, bit_offset;
u32 ptc_value;
u64 ptc_mask;
struct acpi_processor_throttling *throttling;
int ret = -1;
throttling = &pr->throttling;
switch (throttling->status_register.space_id) {
case ACPI_ADR_SPACE_SYSTEM_IO:
bit_width = throttling->status_register.bit_width;
bit_offset = throttling->status_register.bit_offset;
acpi_os_read_port((acpi_io_address) throttling->status_register.
address, &ptc_value,
(u32) (bit_width + bit_offset));
ptc_mask = (1 << bit_width) - 1;
*value = (u64) ((ptc_value >> bit_offset) & ptc_mask);
ret = 0;
break;
case ACPI_ADR_SPACE_FIXED_HARDWARE:
ret = acpi_throttling_rdmsr(value);
break;
default:
printk(KERN_ERR PREFIX "Unknown addr space %d\n",
(u32) (throttling->status_register.space_id));
}
return ret;
}
static int acpi_write_throttling_state(struct acpi_processor *pr,
u64 value)
{
u32 bit_width, bit_offset;
u64 ptc_value;
u64 ptc_mask;
struct acpi_processor_throttling *throttling;
int ret = -1;
throttling = &pr->throttling;
switch (throttling->control_register.space_id) {
case ACPI_ADR_SPACE_SYSTEM_IO:
bit_width = throttling->control_register.bit_width;
bit_offset = throttling->control_register.bit_offset;
ptc_mask = (1 << bit_width) - 1;
ptc_value = value & ptc_mask;
acpi_os_write_port((acpi_io_address) throttling->
control_register.address,
(u32) (ptc_value << bit_offset),
(u32) (bit_width + bit_offset));
ret = 0;
break;
case ACPI_ADR_SPACE_FIXED_HARDWARE:
ret = acpi_throttling_wrmsr(value);
break;
default:
printk(KERN_ERR PREFIX "Unknown addr space %d\n",
(u32) (throttling->control_register.space_id));
}
return ret;
}
static int acpi_get_throttling_state(struct acpi_processor *pr,
u64 value)
{
int i;
for (i = 0; i < pr->throttling.state_count; i++) {
struct acpi_processor_tx_tss *tx =
(struct acpi_processor_tx_tss *)&(pr->throttling.
states_tss[i]);
if (tx->control == value)
return i;
}
return -1;
}
static int acpi_get_throttling_value(struct acpi_processor *pr,
int state, u64 *value)
{
int ret = -1;
if (state >= 0 && state <= pr->throttling.state_count) {
struct acpi_processor_tx_tss *tx =
(struct acpi_processor_tx_tss *)&(pr->throttling.
states_tss[state]);
*value = tx->control;
ret = 0;
}
return ret;
}
static int acpi_processor_get_throttling_ptc(struct acpi_processor *pr)
{
int state = 0;
int ret;
u64 value;
if (!pr)
return -EINVAL;
if (!pr->flags.throttling)
return -ENODEV;
pr->throttling.state = 0;
value = 0;
ret = acpi_read_throttling_status(pr, &value);
if (ret >= 0) {
state = acpi_get_throttling_state(pr, value);
if (state == -1) {
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"Invalid throttling state, reset\n"));
state = 0;
ret = __acpi_processor_set_throttling(pr, state, true,
true);
if (ret)
return ret;
}
pr->throttling.state = state;
}
return 0;
}
static long __acpi_processor_get_throttling(void *data)
{
struct acpi_processor *pr = data;
return pr->throttling.acpi_processor_get_throttling(pr);
}
static int call_on_cpu(int cpu, long (*fn)(void *), void *arg, bool direct)
{
if (direct || (is_percpu_thread() && cpu == smp_processor_id()))
return fn(arg);
return work_on_cpu(cpu, fn, arg);
}
static int acpi_processor_get_throttling(struct acpi_processor *pr)
{
if (!pr)
return -EINVAL;
if (!pr->flags.throttling)
return -ENODEV;
/*
* This is either called from the CPU hotplug callback of
* processor_driver or via the ACPI probe function. In the latter
* case the CPU is not guaranteed to be online. Both call sites are
* protected against CPU hotplug.
*/
if (!cpu_online(pr->id))
return -ENODEV;
return call_on_cpu(pr->id, __acpi_processor_get_throttling, pr, false);
}
static int acpi_processor_get_fadt_info(struct acpi_processor *pr)
{
int i, step;
if (!pr->throttling.address) {
ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No throttling register\n"));
return -EINVAL;
} else if (!pr->throttling.duty_width) {
ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No throttling states\n"));
return -EINVAL;
}
/* TBD: Support duty_cycle values that span bit 4. */
else if ((pr->throttling.duty_offset + pr->throttling.duty_width) > 4) {
printk(KERN_WARNING PREFIX "duty_cycle spans bit 4\n");
return -EINVAL;
}
pr->throttling.state_count = 1 << acpi_gbl_FADT.duty_width;
/*
* Compute state values. Note that throttling displays a linear power
* performance relationship (at 50% performance the CPU will consume
* 50% power). Values are in 1/10th of a percent to preserve accuracy.
*/
step = (1000 / pr->throttling.state_count);
for (i = 0; i < pr->throttling.state_count; i++) {
pr->throttling.states[i].performance = 1000 - step * i;
pr->throttling.states[i].power = 1000 - step * i;
}
return 0;
}
static int acpi_processor_set_throttling_fadt(struct acpi_processor *pr,
int state, bool force)
{
u32 value = 0;
u32 duty_mask = 0;
u32 duty_value = 0;
if (!pr)
return -EINVAL;
if ((state < 0) || (state > (pr->throttling.state_count - 1)))
return -EINVAL;
if (!pr->flags.throttling)
return -ENODEV;
if (!force && (state == pr->throttling.state))
return 0;
if (state < pr->throttling_platform_limit)
return -EPERM;
/*
* Calculate the duty_value and duty_mask.
*/
if (state) {
duty_value = pr->throttling.state_count - state;
duty_value <<= pr->throttling.duty_offset;
/* Used to clear all duty_value bits */
duty_mask = pr->throttling.state_count - 1;
duty_mask <<= acpi_gbl_FADT.duty_offset;
duty_mask = ~duty_mask;
}
local_irq_disable();
/*
* Disable throttling by writing a 0 to bit 4. Note that we must
* turn it off before you can change the duty_value.
*/
value = inl(pr->throttling.address);
if (value & 0x10) {
value &= 0xFFFFFFEF;
outl(value, pr->throttling.address);
}
/*
* Write the new duty_value and then enable throttling. Note
* that a state value of 0 leaves throttling disabled.
*/
if (state) {
value &= duty_mask;
value |= duty_value;
outl(value, pr->throttling.address);
value |= 0x00000010;
outl(value, pr->throttling.address);
}
pr->throttling.state = state;
local_irq_enable();
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"Throttling state set to T%d (%d%%)\n", state,
(pr->throttling.states[state].performance ? pr->
throttling.states[state].performance / 10 : 0)));
return 0;
}
static int acpi_processor_set_throttling_ptc(struct acpi_processor *pr,
int state, bool force)
{
int ret;
u64 value;
if (!pr)
return -EINVAL;
if ((state < 0) || (state > (pr->throttling.state_count - 1)))
return -EINVAL;
if (!pr->flags.throttling)
return -ENODEV;
if (!force && (state == pr->throttling.state))
return 0;
if (state < pr->throttling_platform_limit)
return -EPERM;
value = 0;
ret = acpi_get_throttling_value(pr, state, &value);
if (ret >= 0) {
acpi_write_throttling_state(pr, value);
pr->throttling.state = state;
}
return 0;
}
static long acpi_processor_throttling_fn(void *data)
{
struct acpi_processor_throttling_arg *arg = data;
struct acpi_processor *pr = arg->pr;
return pr->throttling.acpi_processor_set_throttling(pr,
arg->target_state, arg->force);
}
static int __acpi_processor_set_throttling(struct acpi_processor *pr,
int state, bool force, bool direct)
{
int ret = 0;
unsigned int i;
struct acpi_processor *match_pr;
struct acpi_processor_throttling *p_throttling;
struct acpi_processor_throttling_arg arg;
struct throttling_tstate t_state;
if (!pr)
return -EINVAL;
if (!pr->flags.throttling)
return -ENODEV;
if ((state < 0) || (state > (pr->throttling.state_count - 1)))
return -EINVAL;
if (cpu_is_offline(pr->id)) {
/*
* the cpu pointed by pr->id is offline. Unnecessary to change
* the throttling state any more.
*/
return -ENODEV;
}
t_state.target_state = state;
p_throttling = &(pr->throttling);
/*
* The throttling notifier will be called for every
* affected cpu in order to get one proper T-state.
* The notifier event is THROTTLING_PRECHANGE.
*/
for_each_cpu_and(i, cpu_online_mask, p_throttling->shared_cpu_map) {
t_state.cpu = i;
acpi_processor_throttling_notifier(THROTTLING_PRECHANGE,
&t_state);
}
/*
* The function of acpi_processor_set_throttling will be called
* to switch T-state. If the coordination type is SW_ALL or HW_ALL,
* it is necessary to call it for every affected cpu. Otherwise
* it can be called only for the cpu pointed by pr.
*/
if (p_throttling->shared_type == DOMAIN_COORD_TYPE_SW_ANY) {
arg.pr = pr;
arg.target_state = state;
arg.force = force;
ret = call_on_cpu(pr->id, acpi_processor_throttling_fn, &arg,
direct);
} else {
/*
* When the T-state coordination is SW_ALL or HW_ALL,
* it is necessary to set T-state for every affected
* cpus.
*/
for_each_cpu_and(i, cpu_online_mask,
p_throttling->shared_cpu_map) {
match_pr = per_cpu(processors, i);
/*
* If the pointer is invalid, we will report the
* error message and continue.
*/
if (!match_pr) {
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"Invalid Pointer for CPU %d\n", i));
continue;
}
/*
* If the throttling control is unsupported on CPU i,
* we will report the error message and continue.
*/
if (!match_pr->flags.throttling) {
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"Throttling Control is unsupported "
"on CPU %d\n", i));
continue;
}
arg.pr = match_pr;
arg.target_state = state;
arg.force = force;
ret = call_on_cpu(pr->id, acpi_processor_throttling_fn,
&arg, direct);
}
}
/*
* After the set_throttling is called, the
* throttling notifier is called for every
* affected cpu to update the T-states.
* The notifier event is THROTTLING_POSTCHANGE
*/
for_each_cpu_and(i, cpu_online_mask, p_throttling->shared_cpu_map) {
t_state.cpu = i;
acpi_processor_throttling_notifier(THROTTLING_POSTCHANGE,
&t_state);
}
return ret;
}
int acpi_processor_set_throttling(struct acpi_processor *pr, int state,
bool force)
{
return __acpi_processor_set_throttling(pr, state, force, false);
}
int acpi_processor_get_throttling_info(struct acpi_processor *pr)
{
int result = 0;
struct acpi_processor_throttling *pthrottling;
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"pblk_address[0x%08x] duty_offset[%d] duty_width[%d]\n",
pr->throttling.address,
pr->throttling.duty_offset,
pr->throttling.duty_width));
/*
* Evaluate _PTC, _TSS and _TPC
* They must all be present or none of them can be used.
*/
if (acpi_processor_get_throttling_control(pr) ||
acpi_processor_get_throttling_states(pr) ||
acpi_processor_get_platform_limit(pr))
{
pr->throttling.acpi_processor_get_throttling =
&acpi_processor_get_throttling_fadt;
pr->throttling.acpi_processor_set_throttling =
&acpi_processor_set_throttling_fadt;
if (acpi_processor_get_fadt_info(pr))
return 0;
} else {
pr->throttling.acpi_processor_get_throttling =
&acpi_processor_get_throttling_ptc;
pr->throttling.acpi_processor_set_throttling =
&acpi_processor_set_throttling_ptc;
}
/*
* If TSD package for one CPU can't be parsed successfully, it means
* that this CPU will have no coordination with other CPUs.
*/
if (acpi_processor_get_tsd(pr)) {
pthrottling = &pr->throttling;
pthrottling->tsd_valid_flag = 0;
cpumask_set_cpu(pr->id, pthrottling->shared_cpu_map);
pthrottling->shared_type = DOMAIN_COORD_TYPE_SW_ALL;
}
/*
* PIIX4 Errata: We don't support throttling on the original PIIX4.
* This shouldn't be an issue as few (if any) mobile systems ever
* used this part.
*/
if (errata.piix4.throttle) {
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"Throttling not supported on PIIX4 A- or B-step\n"));
return 0;
}
ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d throttling states\n",
pr->throttling.state_count));
pr->flags.throttling = 1;
/*
* Disable throttling (if enabled). We'll let subsequent policy (e.g.
* thermal) decide to lower performance if it so chooses, but for now
* we'll crank up the speed.
*/
result = acpi_processor_get_throttling(pr);
if (result)
goto end;
if (pr->throttling.state) {
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"Disabling throttling (was T%d)\n",
pr->throttling.state));
result = acpi_processor_set_throttling(pr, 0, false);
if (result)
goto end;
}
end:
if (result)
pr->flags.throttling = 0;
return result;
}