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Merge branch 'x86/idle' into sched/core
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Merge these x86 specific bits - we are going to add generic bits as well.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Ingo Molnar committed Jan 13, 2014
2 parents 0bd3a17 + 7d590cc commit c9c8986
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Showing 8 changed files with 48 additions and 78 deletions.
43 changes: 43 additions & 0 deletions arch/x86/include/asm/mwait.h
Original file line number Diff line number Diff line change
@@ -1,6 +1,8 @@
#ifndef _ASM_X86_MWAIT_H
#define _ASM_X86_MWAIT_H

#include <linux/sched.h>

#define MWAIT_SUBSTATE_MASK 0xf
#define MWAIT_CSTATE_MASK 0xf
#define MWAIT_SUBSTATE_SIZE 4
Expand All @@ -13,4 +15,45 @@

#define MWAIT_ECX_INTERRUPT_BREAK 0x1

static inline void __monitor(const void *eax, unsigned long ecx,
unsigned long edx)
{
/* "monitor %eax, %ecx, %edx;" */
asm volatile(".byte 0x0f, 0x01, 0xc8;"
:: "a" (eax), "c" (ecx), "d"(edx));
}

static inline void __mwait(unsigned long eax, unsigned long ecx)
{
/* "mwait %eax, %ecx;" */
asm volatile(".byte 0x0f, 0x01, 0xc9;"
:: "a" (eax), "c" (ecx));
}

/*
* This uses new MONITOR/MWAIT instructions on P4 processors with PNI,
* which can obviate IPI to trigger checking of need_resched.
* We execute MONITOR against need_resched and enter optimized wait state
* through MWAIT. Whenever someone changes need_resched, we would be woken
* up from MWAIT (without an IPI).
*
* New with Core Duo processors, MWAIT can take some hints based on CPU
* capability.
*/
static inline void mwait_idle_with_hints(unsigned long eax, unsigned long ecx)
{
if (!current_set_polling_and_test()) {
if (static_cpu_has(X86_FEATURE_CLFLUSH_MONITOR)) {
mb();
clflush((void *)&current_thread_info()->flags);
mb();
}

__monitor((void *)&current_thread_info()->flags, 0, 0);
if (!need_resched())
__mwait(eax, ecx);
}
__current_clr_polling();
}

#endif /* _ASM_X86_MWAIT_H */
23 changes: 0 additions & 23 deletions arch/x86/include/asm/processor.h
Original file line number Diff line number Diff line change
Expand Up @@ -700,29 +700,6 @@ static inline void sync_core(void)
#endif
}

static inline void __monitor(const void *eax, unsigned long ecx,
unsigned long edx)
{
/* "monitor %eax, %ecx, %edx;" */
asm volatile(".byte 0x0f, 0x01, 0xc8;"
:: "a" (eax), "c" (ecx), "d"(edx));
}

static inline void __mwait(unsigned long eax, unsigned long ecx)
{
/* "mwait %eax, %ecx;" */
asm volatile(".byte 0x0f, 0x01, 0xc9;"
:: "a" (eax), "c" (ecx));
}

static inline void __sti_mwait(unsigned long eax, unsigned long ecx)
{
trace_hardirqs_on();
/* "mwait %eax, %ecx;" */
asm volatile("sti; .byte 0x0f, 0x01, 0xc9;"
:: "a" (eax), "c" (ecx));
}

extern void select_idle_routine(const struct cpuinfo_x86 *c);
extern void init_amd_e400_c1e_mask(void);

Expand Down
23 changes: 0 additions & 23 deletions arch/x86/kernel/acpi/cstate.c
Original file line number Diff line number Diff line change
Expand Up @@ -150,29 +150,6 @@ int acpi_processor_ffh_cstate_probe(unsigned int cpu,
}
EXPORT_SYMBOL_GPL(acpi_processor_ffh_cstate_probe);

/*
* This uses new MONITOR/MWAIT instructions on P4 processors with PNI,
* which can obviate IPI to trigger checking of need_resched.
* We execute MONITOR against need_resched and enter optimized wait state
* through MWAIT. Whenever someone changes need_resched, we would be woken
* up from MWAIT (without an IPI).
*
* New with Core Duo processors, MWAIT can take some hints based on CPU
* capability.
*/
void mwait_idle_with_hints(unsigned long ax, unsigned long cx)
{
if (!need_resched()) {
if (this_cpu_has(X86_FEATURE_CLFLUSH_MONITOR))
clflush((void *)&current_thread_info()->flags);

__monitor((void *)&current_thread_info()->flags, 0, 0);
smp_mb();
if (!need_resched())
__mwait(ax, cx);
}
}

void acpi_processor_ffh_cstate_enter(struct acpi_processor_cx *cx)
{
unsigned int cpu = smp_processor_id();
Expand Down
2 changes: 2 additions & 0 deletions arch/x86/kernel/smpboot.c
Original file line number Diff line number Diff line change
Expand Up @@ -1417,7 +1417,9 @@ static inline void mwait_play_dead(void)
* The WBINVD is insufficient due to the spurious-wakeup
* case where we return around the loop.
*/
mb();
clflush(mwait_ptr);
mb();
__monitor(mwait_ptr, 0, 0);
mb();
__mwait(eax, 0);
Expand Down
5 changes: 1 addition & 4 deletions drivers/acpi/acpi_pad.c
Original file line number Diff line number Diff line change
Expand Up @@ -193,10 +193,7 @@ static int power_saving_thread(void *data)
CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &cpu);
stop_critical_timings();

__monitor((void *)&current_thread_info()->flags, 0, 0);
smp_mb();
if (!need_resched())
__mwait(power_saving_mwait_eax, 1);
mwait_idle_with_hints(power_saving_mwait_eax, 1);

start_critical_timings();
if (lapic_marked_unstable)
Expand Down
15 changes: 0 additions & 15 deletions drivers/acpi/processor_idle.c
Original file line number Diff line number Diff line change
Expand Up @@ -727,11 +727,6 @@ static int acpi_idle_enter_c1(struct cpuidle_device *dev,
if (unlikely(!pr))
return -EINVAL;

if (cx->entry_method == ACPI_CSTATE_FFH) {
if (current_set_polling_and_test())
return -EINVAL;
}

lapic_timer_state_broadcast(pr, cx, 1);
acpi_idle_do_entry(cx);

Expand Down Expand Up @@ -785,11 +780,6 @@ static int acpi_idle_enter_simple(struct cpuidle_device *dev,
if (unlikely(!pr))
return -EINVAL;

if (cx->entry_method == ACPI_CSTATE_FFH) {
if (current_set_polling_and_test())
return -EINVAL;
}

/*
* Must be done before busmaster disable as we might need to
* access HPET !
Expand Down Expand Up @@ -841,11 +831,6 @@ static int acpi_idle_enter_bm(struct cpuidle_device *dev,
}
}

if (cx->entry_method == ACPI_CSTATE_FFH) {
if (current_set_polling_and_test())
return -EINVAL;
}

acpi_unlazy_tlb(smp_processor_id());

/* Tell the scheduler that we are going deep-idle: */
Expand Down
11 changes: 1 addition & 10 deletions drivers/idle/intel_idle.c
Original file line number Diff line number Diff line change
Expand Up @@ -377,16 +377,7 @@ static int intel_idle(struct cpuidle_device *dev,
if (!(lapic_timer_reliable_states & (1 << (cstate))))
clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &cpu);

if (!current_set_polling_and_test()) {

if (this_cpu_has(X86_FEATURE_CLFLUSH_MONITOR))
clflush((void *)&current_thread_info()->flags);

__monitor((void *)&current_thread_info()->flags, 0, 0);
smp_mb();
if (!need_resched())
__mwait(eax, ecx);
}
mwait_idle_with_hints(eax, ecx);

if (!(lapic_timer_reliable_states & (1 << (cstate))))
clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &cpu);
Expand Down
4 changes: 1 addition & 3 deletions drivers/thermal/intel_powerclamp.c
Original file line number Diff line number Diff line change
Expand Up @@ -438,9 +438,7 @@ static int clamp_thread(void *arg)
*/
local_touch_nmi();
stop_critical_timings();
__monitor((void *)&current_thread_info()->flags, 0, 0);
cpu_relax(); /* allow HT sibling to run */
__mwait(eax, ecx);
mwait_idle_with_hints(eax, ecx);
start_critical_timings();
atomic_inc(&idle_wakeup_counter);
}
Expand Down

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