arm_pmu: acpi: request IRQs up-front

We can't request IRQs in atomic context, so for ACPI systems we'll have
to request them up-front, and later associate them with CPUs.

This patch reorganises the arm_pmu code to do so. As we no longer have
the arm_pmu structure at probe time, a number of prototypes need to be
adjusted, requiring changes to the common arm_pmu code and arm_pmu
platform code.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c
index 2b2af35..0c2ed11 100644 (file)
--- a/drivers/perf/arm_pmu.c
+++ b/drivers/perf/arm_pmu.c
@@ -534,7 +534,7 @@ static int armpmu_count_irq_users(const int irq)
        return count;
 }
 
-void armpmu_free_cpu_irq(int irq, int cpu)
+void armpmu_free_irq(int irq, int cpu)
 {
        if (per_cpu(cpu_irq, cpu) == 0)
                return;
@@ -549,15 +549,7 @@ void armpmu_free_cpu_irq(int irq, int cpu)
        per_cpu(cpu_irq, cpu) = 0;
 }
 
-void armpmu_free_irq(struct arm_pmu *armpmu, int cpu)
-{
-       struct pmu_hw_events __percpu *hw_events = armpmu->hw_events;
-       int irq = per_cpu(hw_events->irq, cpu);
-
-       armpmu_free_cpu_irq(irq, cpu);
-}
-
-int armpmu_request_cpu_irq(int irq, int cpu)
+int armpmu_request_irq(int irq, int cpu)
 {
        int err = 0;
        const irq_handler_t handler = armpmu_dispatch_irq;
@@ -598,16 +590,6 @@ err_out:
        return err;
 }
 
-int armpmu_request_irq(struct arm_pmu *armpmu, int cpu)
-{
-       struct pmu_hw_events __percpu *hw_events = armpmu->hw_events;
-       int irq = per_cpu(hw_events->irq, cpu);
-       if (!irq)
-               return 0;
-
-       return armpmu_request_cpu_irq(irq, cpu);
-}
-
 static int armpmu_get_cpu_irq(struct arm_pmu *pmu, int cpu)
 {
        struct pmu_hw_events __percpu *hw_events = pmu->hw_events;

diff --git a/drivers/perf/arm_pmu_acpi.c b/drivers/perf/arm_pmu_acpi.c
index 09a1a36..0f19751 100644 (file)
--- a/drivers/perf/arm_pmu_acpi.c
+++ b/drivers/perf/arm_pmu_acpi.c
@@ -89,7 +89,13 @@ static int arm_pmu_acpi_parse_irqs(void)
                        pr_warn("No ACPI PMU IRQ for CPU%d\n", cpu);
                }
 
+               /*
+                * Log and request the IRQ so the core arm_pmu code can manage
+                * it. We'll have to sanity-check IRQs later when we associate
+                * them with their PMUs.
+                */
                per_cpu(pmu_irqs, cpu) = irq;
+               armpmu_request_irq(irq, cpu);
        }
 
        return 0;
@@ -205,14 +211,6 @@ static int arm_pmu_acpi_cpu_starting(unsigned int cpu)
        cpumask_set_cpu(cpu, &pmu->supported_cpus);
 
        /*
-        * Log and request the IRQ so the core arm_pmu code can manage it.  In
-        * some situations (e.g. mismatched PPIs), we may fail to request the
-        * IRQ. However, it may be too late for us to do anything about it.
-        * The common ARM PMU code will log a warning in this case.
-        */
-       armpmu_request_irq(pmu, cpu);
-
-       /*
         * Ideally, we'd probe the PMU here when we find the first matching
         * CPU. We can't do that for several reasons; see the comment in
         * arm_pmu_acpi_init().
@@ -281,11 +279,6 @@ static int arm_pmu_acpi_init(void)
        if (acpi_disabled)
                return 0;
 
-       /*
-        * We can't request IRQs yet, since we don't know the cookie value
-        * until we know which CPUs share the same logical PMU. We'll handle
-        * that in arm_pmu_acpi_cpu_starting().
-        */
        ret = arm_pmu_acpi_parse_irqs();
        if (ret)
                return ret;

diff --git a/drivers/perf/arm_pmu_platform.c b/drivers/perf/arm_pmu_platform.c
index 1dc3c1f..7729eda 100644 (file)
--- a/drivers/perf/arm_pmu_platform.c
+++ b/drivers/perf/arm_pmu_platform.c
@@ -159,10 +159,15 @@ static int pmu_parse_irqs(struct arm_pmu *pmu)
 
 static int armpmu_request_irqs(struct arm_pmu *armpmu)
 {
+       struct pmu_hw_events __percpu *hw_events = armpmu->hw_events;
        int cpu, err;
 
        for_each_cpu(cpu, &armpmu->supported_cpus) {
-               err = armpmu_request_irq(armpmu, cpu);
+               int irq = per_cpu(hw_events->irq, cpu);
+               if (!irq)
+                       continue;
+
+               err = armpmu_request_irq(irq, cpu);
                if (err)
                        break;
        }
@@ -173,9 +178,13 @@ static int armpmu_request_irqs(struct arm_pmu *armpmu)
 static void armpmu_free_irqs(struct arm_pmu *armpmu)
 {
        int cpu;
+       struct pmu_hw_events __percpu *hw_events = armpmu->hw_events;
 
-       for_each_cpu(cpu, &armpmu->supported_cpus)
-               armpmu_free_irq(armpmu, cpu);
+       for_each_cpu(cpu, &armpmu->supported_cpus) {
+               int irq = per_cpu(hw_events->irq, cpu);
+
+               armpmu_free_irq(irq, cpu);
+       }
 }
 
 int arm_pmu_device_probe(struct platform_device *pdev,

diff --git a/include/linux/perf/arm_pmu.h b/include/linux/perf/arm_pmu.h
index feec9e7..40036a5 100644 (file)
--- a/include/linux/perf/arm_pmu.h
+++ b/include/linux/perf/arm_pmu.h
@@ -14,6 +14,7 @@
 
 #include <linux/interrupt.h>
 #include <linux/perf_event.h>
+#include <linux/platform_device.h>
 #include <linux/sysfs.h>
 #include <asm/cputype.h>
 
@@ -159,8 +160,8 @@ struct arm_pmu *armpmu_alloc(void);
 struct arm_pmu *armpmu_alloc_atomic(void);
 void armpmu_free(struct arm_pmu *pmu);
 int armpmu_register(struct arm_pmu *pmu);
-int armpmu_request_irq(struct arm_pmu *armpmu, int cpu);
-void armpmu_free_irq(struct arm_pmu *armpmu, int cpu);
+int armpmu_request_irq(int irq, int cpu);
+void armpmu_free_irq(int irq, int cpu);
 
 #define ARMV8_PMU_PDEV_NAME "armv8-pmu"