Commit 32d4fd57 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Rafael J. Wysocki
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cpuidle,intel_idle: Fix CPUIDLE_FLAG_IRQ_ENABLE 



Commit c227233a ("intel_idle: enable interrupts before C1 on
Xeons") wrecked intel_idle in two ways:

 - must not have tracing in idle functions
 - must return with IRQs disabled

Additionally, it added a branch for no good reason.

Fixes: c227233a ("intel_idle: enable interrupts before C1 on Xeons")
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
[ rjw: Moved the intel_idle() kerneldoc comment next to the function ]
Cc: 5.16+ <stable@vger.kernel.org> # 5.16+
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent f2906aa8

drivers/idle/intel_idle.c

+25 −7
Original line number Diff line number Diff line
@@ -115,6 +115,18 @@ static unsigned int mwait_substates __initdata; 
#define flg2MWAIT(flags) (((flags) >> 24) & 0xFF)

#define MWAIT2flg(eax) ((eax & 0xFF) << 24)



static __always_inline int __intel_idle(struct cpuidle_device *dev,

					struct cpuidle_driver *drv, int index)

{

	struct cpuidle_state *state = &drv->states[index];

	unsigned long eax = flg2MWAIT(state->flags);

	unsigned long ecx = 1; /* break on interrupt flag */



	mwait_idle_with_hints(eax, ecx);



	return index;

}



/**

 * intel_idle - Ask the processor to enter the given idle state.

 * @dev: cpuidle device of the target CPU.
@@ -132,16 +144,19 @@ static unsigned int mwait_substates __initdata; 
static __cpuidle int intel_idle(struct cpuidle_device *dev,

				struct cpuidle_driver *drv, int index)

{

	struct cpuidle_state *state = &drv->states[index];

	unsigned long eax = flg2MWAIT(state->flags);

	unsigned long ecx = 1; /* break on interrupt flag */

	return __intel_idle(dev, drv, index);

}



	if (state->flags & CPUIDLE_FLAG_IRQ_ENABLE)

		local_irq_enable();

static __cpuidle int intel_idle_irq(struct cpuidle_device *dev,

				    struct cpuidle_driver *drv, int index)

{

	int ret;



	mwait_idle_with_hints(eax, ecx);

	raw_local_irq_enable();

	ret = __intel_idle(dev, drv, index);

	raw_local_irq_disable();



	return index;

	return ret;

}



/**
@@ -1801,6 +1816,9 @@ static void __init intel_idle_init_cstates_icpu(struct cpuidle_driver *drv) 
		/* Structure copy. */

		drv->states[drv->state_count] = cpuidle_state_table[cstate];



		if (cpuidle_state_table[cstate].flags & CPUIDLE_FLAG_IRQ_ENABLE)

			drv->states[drv->state_count].enter = intel_idle_irq;



		if ((disabled_states_mask & BIT(drv->state_count)) ||

		    ((icpu->use_acpi || force_use_acpi) &&

		     intel_idle_off_by_default(mwait_hint) &&