Commit 56957940 authored by Vineet Gupta's avatar Vineet Gupta
Browse files

ARC: opencode arc_request_percpu_irq 



- The idea is to remove the API usage since it has a subltle
  design flaw - relies on being called on cpu0 first. This is true for
  some early per cpu irqs such as TIMER/IPI, but not for late probed
  per cpu peripherals such a perf. And it's usage in perf has already
  bitten us once: see c6317bc7
  ("ARCv2: perf: Ensure perf intr gets enabled on all cores") where we
  ended up open coding it anyways

- The seeming duplication will go away once we start using cpu notifier
  for timer setup

Signed-off-by: default avatarVineet Gupta <vgupta@synopsys.com>
parent db4c4426

arch/arc/include/asm/irq.h

+0 −3
Original line number Diff line number Diff line
@@ -26,8 +26,5 @@ 


extern void arc_init_IRQ(void);

void arc_local_timer_setup(void);

void arc_request_percpu_irq(int irq, int cpu,

                            irqreturn_t (*isr)(int irq, void *dev),

                            const char *irq_nm, void *percpu_dev);



#endif

arch/arc/kernel/irq.c

+0 −29
Original line number Diff line number Diff line
@@ -50,32 +50,3 @@ void arch_do_IRQ(unsigned int irq, struct pt_regs *regs) 
	irq_exit();

	set_irq_regs(old_regs);

}
 


/*

 * API called for requesting percpu interrupts - called by each CPU

 *  - For boot CPU, actually request the IRQ with genirq core + enables

 *  - For subsequent callers only enable called locally

 *

 * Relies on being called by boot cpu first (i.e. request called ahead) of

 * any enable as expected by genirq. Hence Suitable only for TIMER, IPI

 * which are guaranteed to be setup on boot core first.

 * Late probed peripherals such as perf can't use this as there no guarantee

 * of being called on boot CPU first.

 */



void arc_request_percpu_irq(int irq, int cpu,

                            irqreturn_t (*isr)(int irq, void *dev),

                            const char *irq_nm,

                            void *percpu_dev)

{

	/* Boot cpu calls request, all call enable */

	if (!cpu) {

		int rc;



		rc = request_percpu_irq(irq, isr, irq_nm, percpu_dev);

		if (rc)

			panic("Percpu IRQ request failed for %d\n", irq);

	}



	enable_percpu_irq(irq, 0);

}

arch/arc/kernel/smp.c

+14 −1
Original line number Diff line number Diff line
@@ -346,6 +346,10 @@ irqreturn_t do_IPI(int irq, void *dev_id) 


/*

 * API called by platform code to hookup arch-common ISR to their IPI IRQ

 *

 * Note: If IPI is provided by platform (vs. say ARC MCIP), their intc setup/map

 * function needs to call call irq_set_percpu_devid() for IPI IRQ, otherwise

 * request_percpu_irq() below will fail

 */

static DEFINE_PER_CPU(int, ipi_dev);
@@ -353,7 +357,16 @@ int smp_ipi_irq_setup(int cpu, int irq) 
{

	int *dev = per_cpu_ptr(&ipi_dev, cpu);



	arc_request_percpu_irq(irq, cpu, do_IPI, "IPI Interrupt", dev);

	/* Boot cpu calls request, all call enable */

	if (!cpu) {

		int rc;



		rc = request_percpu_irq(irq, do_IPI, "IPI Interrupt", dev);

		if (rc)

			panic("Percpu IRQ request failed for %d\n", irq);

	}



	enable_percpu_irq(irq, 0);



	return 0;

}

arch/arc/kernel/time.c

+11 −3
Original line number Diff line number Diff line
@@ -251,14 +251,22 @@ void arc_local_timer_setup() 
{

	struct clock_event_device *evt = this_cpu_ptr(&arc_clockevent_device);

	int cpu = smp_processor_id();

	int irq = TIMER0_IRQ;



	evt->cpumask = cpumask_of(cpu);

	clockevents_config_and_register(evt, arc_get_core_freq(),

					0, ARC_TIMER_MAX);



	/* setup the per-cpu timer IRQ handler - for all cpus */

	arc_request_percpu_irq(TIMER0_IRQ, cpu, timer_irq_handler,

	if (!cpu) {

		int rc;



		rc = request_percpu_irq(irq, timer_irq_handler,

					"Timer0 (per-cpu-tick)", evt);

		if (rc)

			panic("Percpu IRQ request failed for TIMER\n");

	}



	enable_percpu_irq(irq, 0);

}



/*

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