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Commit 4b490f2e authored by Mahesh Sivasubramanian's avatar Mahesh Sivasubramanian Committed by Lina Iyer
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ARM64: smp: Prevent cluster LPM modes when pending IPIs on cluster CPUs 



LPM modes can fail if there is a pending IPI interrupt at GIC CPU
interface. On some usecases frequent failure of LPM modes can cause
power and performance degradation. Hence, prevent cluster low power
modes when there is a pending IPI on cluster CPUs.

This patch has been combined with the following patches:
	- 'commit c3d3af5dce1fb52 ("ARM: smp: Remove use of
	  IPI_CALL_FUNC_SINGLE")'
	- 'commit 0a061eca16bf0d8 ("ARM: kernel: smp: Clear Pending IPI
	  flag after handling")'

Change-Id: Id8a0ac24e4867ef824e0a6f11d989f1e1a2b0e93
Signed-off-by: default avatarMahesh Sivasubramanian <msivasub@codeaurora.org>
Signed-off-by: default avatarMurali Nalajala <mnalajal@codeaurora.org>
[satyap: trivial merge conflict resolution]
Signed-off-by: default avatarSatya Durga Srinivasu Prabhala <satyap@codeaurora.org>
parent 99a3b027

arch/arm/kernel/smp.c

+32 −8
Original line number Diff line number Diff line
@@ -498,6 +498,18 @@ static void smp_cross_call(const struct cpumask *target, unsigned int ipinr) 
	__smp_cross_call(target, ipinr);

}



DEFINE_PER_CPU(bool, pending_ipi);

static void smp_cross_call_common(const struct cpumask *cpumask,

						unsigned int func)

{

	unsigned int cpu;



	for_each_cpu(cpu, cpumask)

		per_cpu(pending_ipi, cpu) = true;



	smp_cross_call(cpumask, func);

}



void show_ipi_list(struct seq_file *p, int prec)

{

	unsigned int cpu, i;
@@ -526,31 +538,32 @@ u64 smp_irq_stat_cpu(unsigned int cpu) 


void arch_send_call_function_ipi_mask(const struct cpumask *mask)

{

	smp_cross_call(mask, IPI_CALL_FUNC);

	smp_cross_call_common(mask, IPI_CALL_FUNC);

}



void arch_send_wakeup_ipi_mask(const struct cpumask *mask)

{

	smp_cross_call(mask, IPI_WAKEUP);

	smp_cross_call_common(mask, IPI_WAKEUP);

}



void arch_send_call_function_single_ipi(int cpu)

{

	smp_cross_call(cpumask_of(cpu), IPI_CALL_FUNC);

	smp_cross_call_common(cpumask_of(cpu), IPI_CALL_FUNC);

}



#ifdef CONFIG_IRQ_WORK

void arch_irq_work_raise(void)

{

	if (arch_irq_work_has_interrupt())

		smp_cross_call(cpumask_of(smp_processor_id()), IPI_IRQ_WORK);

		smp_cross_call_common(cpumask_of(smp_processor_id()),

				IPI_IRQ_WORK);

}

#endif



#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST

void tick_broadcast(const struct cpumask *mask)

{

	smp_cross_call(mask, IPI_TIMER);

	smp_cross_call_common(mask, IPI_TIMER);

}

#endif
@@ -666,12 +679,14 @@ void handle_IPI(int ipinr, struct pt_regs *regs) 


	if ((unsigned)ipinr < NR_IPI)

		trace_ipi_exit_rcuidle(ipi_types[ipinr]);



	per_cpu(pending_ipi, cpu) = false;

	set_irq_regs(old_regs);

}



void smp_send_reschedule(int cpu)

{

	smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);

	smp_cross_call_common(cpumask_of(cpu), IPI_RESCHEDULE);

}



void smp_send_stop(void)
@@ -682,7 +697,7 @@ void smp_send_stop(void) 
	cpumask_copy(&mask, cpu_online_mask);

	cpumask_clear_cpu(smp_processor_id(), &mask);

	if (!cpumask_empty(&mask))

		smp_cross_call(&mask, IPI_CPU_STOP);

		smp_cross_call_common(&mask, IPI_CPU_STOP);



	/* Wait up to one second for other CPUs to stop */

	timeout = USEC_PER_SEC;
@@ -755,7 +770,16 @@ core_initcall(register_cpufreq_notifier); 


static void raise_nmi(cpumask_t *mask)

{

	smp_cross_call(mask, IPI_CPU_BACKTRACE);

	/*

	 * Generate the backtrace directly if we are running in a calling

	 * context that is not preemptible by the backtrace IPI. Note

	 * that nmi_cpu_backtrace() automatically removes the current cpu

	 * from mask.

	 */

	if (cpumask_test_cpu(smp_processor_id(), mask) && irqs_disabled())

		nmi_cpu_backtrace(NULL);



	smp_cross_call_common(mask, IPI_CPU_BACKTRACE);

}



void arch_trigger_cpumask_backtrace(const cpumask_t *mask, bool exclude_self)

arch/arm64/kernel/smp.c

+19 −8
Original line number Diff line number Diff line
@@ -594,6 +594,18 @@ static void __init acpi_parse_and_init_cpus(void) 
#else

#define acpi_parse_and_init_cpus(...)	do { } while (0)

#endif

void (*__smp_cross_call)(const struct cpumask *, unsigned int);

DEFINE_PER_CPU(bool, pending_ipi);



void smp_cross_call_common(const struct cpumask *cpumask, unsigned int func)

{

	unsigned int cpu;



	for_each_cpu(cpu, cpumask)

		per_cpu(pending_ipi, cpu) = true;



	__smp_cross_call(cpumask, func);

}



/*

 * Enumerate the possible CPU set from the device tree and build the
@@ -735,8 +747,6 @@ void __init smp_prepare_cpus(unsigned int max_cpus) 
	}

}



void (*__smp_cross_call)(const struct cpumask *, unsigned int);



void __init set_smp_cross_call(void (*fn)(const struct cpumask *, unsigned int))

{

	__smp_cross_call = fn;
@@ -786,18 +796,18 @@ u64 smp_irq_stat_cpu(unsigned int cpu) 


void arch_send_call_function_ipi_mask(const struct cpumask *mask)

{

	smp_cross_call(mask, IPI_CALL_FUNC);

	smp_cross_call_common(mask, IPI_CALL_FUNC);

}



void arch_send_call_function_single_ipi(int cpu)

{

	smp_cross_call(cpumask_of(cpu), IPI_CALL_FUNC);

	smp_cross_call_common(cpumask_of(cpu), IPI_CALL_FUNC);

}



#ifdef CONFIG_ARM64_ACPI_PARKING_PROTOCOL

void arch_send_wakeup_ipi_mask(const struct cpumask *mask)

{

	smp_cross_call(mask, IPI_WAKEUP);

	smp_cross_call_common(mask, IPI_WAKEUP);

}

#endif
@@ -933,19 +943,20 @@ void handle_IPI(int ipinr, struct pt_regs *regs) 


	if ((unsigned)ipinr < NR_IPI)

		trace_ipi_exit_rcuidle(ipi_types[ipinr]);

	per_cpu(pending_ipi, cpu) = false;

	set_irq_regs(old_regs);

}



void smp_send_reschedule(int cpu)

{

	BUG_ON(cpu_is_offline(cpu));

	smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);

	smp_cross_call_common(cpumask_of(cpu), IPI_RESCHEDULE);

}



#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST

void tick_broadcast(const struct cpumask *mask)

{

	smp_cross_call(mask, IPI_TIMER);

	smp_cross_call_common(mask, IPI_TIMER);

}

#endif
@@ -961,7 +972,7 @@ void smp_send_stop(void) 


		if (system_state <= SYSTEM_RUNNING)

			pr_crit("SMP: stopping secondary CPUs\n");

		smp_cross_call(&mask, IPI_CPU_STOP);

		smp_cross_call_common(&mask, IPI_CPU_STOP);

	}



	/* Wait up to one second for other CPUs to stop */