From 1a6b69b6548cd0dd82549393f30dd982ceeb79d2 Mon Sep 17 00:00:00 2001 From: Nicolas Pitre Date: Thu, 12 Apr 2012 01:40:31 -0400 Subject: ARM: gic: add CPU migration support This is required by the big.LITTLE switcher code. The gic_migrate_target() changes the CPU interface mapping for the current CPU to redirect SGIs to the specified interface, and it also updates the target CPU for each interrupts to that CPU interface if they were targeting the current interface. Finally, pending SGIs for the current CPU are forwarded to the new interface. Because Linux does not use it, the SGI source information for the forwarded SGIs is not preserved. Neither is the source information for the SGIs sent by the current CPU to other CPUs adjusted to match the new CPU interface mapping. The required registers are banked so only the target CPU could do it. Signed-off-by: Nicolas Pitre --- include/linux/irqchip/arm-gic.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'include') diff --git a/include/linux/irqchip/arm-gic.h b/include/linux/irqchip/arm-gic.h index 3e203eb23cc7..40bfcac95940 100644 --- a/include/linux/irqchip/arm-gic.h +++ b/include/linux/irqchip/arm-gic.h @@ -31,6 +31,8 @@ #define GIC_DIST_TARGET 0x800 #define GIC_DIST_CONFIG 0xc00 #define GIC_DIST_SOFTINT 0xf00 +#define GIC_DIST_SGI_PENDING_CLEAR 0xf10 +#define GIC_DIST_SGI_PENDING_SET 0xf20 #define GICH_HCR 0x0 #define GICH_VTR 0x4 @@ -73,6 +75,8 @@ static inline void gic_init(unsigned int nr, int start, gic_init_bases(nr, start, dist, cpu, 0, NULL); } +void gic_migrate_target(unsigned int new_cpu_id); + #endif /* __ASSEMBLY */ #endif -- cgit v1.2.3 From ed96762e3241f57aa812977cf1920d3ee0363f4d Mon Sep 17 00:00:00 2001 From: Nicolas Pitre Date: Thu, 5 Jul 2012 21:33:26 -0400 Subject: ARM: bL_switcher: do not hardcode GIC IDs in the code Currently, GIC IDs are hardcoded making the code dependent on the 4+4 b.L configuration. Let's allow for GIC IDs to be discovered upon switcher initialization to support other b.L configurations such as the 1+1 one, or 2+3 as on the VExpress TC2. Signed-off-by: Nicolas Pitre --- arch/arm/common/bL_switcher.c | 14 +++++++++++++- drivers/irqchip/irq-gic.c | 21 +++++++++++++++++++++ include/linux/irqchip/arm-gic.h | 1 + 3 files changed, 35 insertions(+), 1 deletion(-) (limited to 'include') diff --git a/arch/arm/common/bL_switcher.c b/arch/arm/common/bL_switcher.c index 50e95d894e35..1c2e5bcfb1f7 100644 --- a/arch/arm/common/bL_switcher.c +++ b/arch/arm/common/bL_switcher.c @@ -110,6 +110,8 @@ static int bL_switchpoint(unsigned long _arg) * Generic switcher interface */ +static unsigned int bL_gic_id[MAX_CPUS_PER_CLUSTER][MAX_NR_CLUSTERS]; + /* * bL_switch_to - Switch to a specific cluster for the current CPU * @new_cluster_id: the ID of the cluster to switch to. @@ -159,7 +161,7 @@ static int bL_switch_to(unsigned int new_cluster_id) this_cpu = smp_processor_id(); /* redirect GIC's SGIs to our counterpart */ - gic_migrate_target(cpuid + ib_cluster*4); + gic_migrate_target(bL_gic_id[cpuid][ib_cluster]); /* * Raise a SGI on the inbound CPU to make sure it doesn't stall @@ -332,6 +334,16 @@ static int __init bL_switcher_halve_cpus(void) cluster = (cpu_logical_map(i) >> 8) & 0xff; if (cpumask_test_cpu(cpu, &common_mask)) { + /* Let's take note of the GIC ID for this CPU */ + int gic_id = gic_get_cpu_id(i); + if (gic_id < 0) { + pr_err("%s: bad GIC ID for CPU %d\n", __func__, i); + return -EINVAL; + } + bL_gic_id[cpu][cluster] = gic_id; + pr_info("GIC ID for CPU %u cluster %u is %u\n", + cpu, cluster, gic_id); + /* * We keep only those logical CPUs which number * is equal to their physical CPU number. This is diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c index 268874ac75e6..3862cb54c714 100644 --- a/drivers/irqchip/irq-gic.c +++ b/drivers/irqchip/irq-gic.c @@ -667,6 +667,27 @@ void gic_raise_softirq(const struct cpumask *mask, unsigned int irq) #endif #ifdef CONFIG_BL_SWITCHER +/* + * gic_get_cpu_id - get the CPU interface ID for the specified CPU + * + * @cpu: the logical CPU number to get the GIC ID for. + * + * Return the CPU interface ID for the given logical CPU number, + * or -1 if the CPU number is too large or the interface ID is + * unknown (more than one bit set). + */ +int gic_get_cpu_id(unsigned int cpu) +{ + unsigned int cpu_bit; + + if (cpu >= NR_GIC_CPU_IF) + return -1; + cpu_bit = gic_cpu_map[cpu]; + if (cpu_bit & (cpu_bit - 1)) + return -1; + return __ffs(cpu_bit); +} + /* * gic_migrate_target - migrate IRQs to another CPU interface * diff --git a/include/linux/irqchip/arm-gic.h b/include/linux/irqchip/arm-gic.h index 40bfcac95940..2d7d47e8dfaf 100644 --- a/include/linux/irqchip/arm-gic.h +++ b/include/linux/irqchip/arm-gic.h @@ -75,6 +75,7 @@ static inline void gic_init(unsigned int nr, int start, gic_init_bases(nr, start, dist, cpu, 0, NULL); } +int gic_get_cpu_id(unsigned int cpu); void gic_migrate_target(unsigned int new_cpu_id); #endif /* __ASSEMBLY */ -- cgit v1.2.3 From eeb446581ba23a5a36b4f5c7bfa2b1f8f7c9fb66 Mon Sep 17 00:00:00 2001 From: Nicolas Pitre Date: Wed, 28 Nov 2012 18:17:25 -0500 Subject: ARM: GIC: function to retrieve the physical address of the SGIR In order to have early assembly code signal other CPUs in the system, we need to get the physical address for the SGIR register used to send IPIs. Because the register will be used with a precomputed CPU interface ID number, there is no need for any locking in the assembly code where this register is written to. Signed-off-by: Nicolas Pitre --- drivers/irqchip/irq-gic.c | 29 +++++++++++++++++++++++++++++ include/linux/irqchip/arm-gic.h | 1 + 2 files changed, 30 insertions(+) (limited to 'include') diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c index 6365b59181ee..09fdf3d574cd 100644 --- a/drivers/irqchip/irq-gic.c +++ b/drivers/irqchip/irq-gic.c @@ -769,6 +769,33 @@ void gic_migrate_target(unsigned int new_cpu_id) } } } + +/* + * gic_get_sgir_physaddr - get the physical address for the SGI register + * + * REturn the physical address of the SGI register to be used + * by some early assembly code when the kernel is not yet available. + */ +static unsigned long gic_dist_physaddr; + +unsigned long gic_get_sgir_physaddr(void) +{ + if (!gic_dist_physaddr) + return 0; + return gic_dist_physaddr + GIC_DIST_SOFTINT; +} + +void __init gic_init_physaddr(struct device_node *node) +{ + struct resource res; + if (of_address_to_resource(node, 0, &res) == 0) { + gic_dist_physaddr = res.start; + pr_info("GIC physical location is %#lx\n", gic_dist_physaddr); + } +} + +#else +#define gic_init_physaddr(node) do { } while (0) #endif static int gic_irq_domain_map(struct irq_domain *d, unsigned int irq, @@ -952,6 +979,8 @@ int __init gic_of_init(struct device_node *node, struct device_node *parent) percpu_offset = 0; gic_init_bases(gic_cnt, -1, dist_base, cpu_base, percpu_offset, node); + if (!gic_cnt) + gic_init_physaddr(node); if (parent) { irq = irq_of_parse_and_map(node, 0); diff --git a/include/linux/irqchip/arm-gic.h b/include/linux/irqchip/arm-gic.h index 46544e381bf9..dc30835099e3 100644 --- a/include/linux/irqchip/arm-gic.h +++ b/include/linux/irqchip/arm-gic.h @@ -78,6 +78,7 @@ static inline void gic_init(unsigned int nr, int start, int gic_get_cpu_id(unsigned int cpu); void gic_migrate_target(unsigned int new_cpu_id); +unsigned long gic_get_sgir_physaddr(void); #endif /* __ASSEMBLY */ -- cgit v1.2.3 From 14d2ca615a85e2dbc744c12c296affd35f119fa7 Mon Sep 17 00:00:00 2001 From: Nicolas Pitre Date: Wed, 28 Nov 2012 18:48:19 -0500 Subject: ARM: GIC: interface to send a SGI directly The regular gic_raise_softirq() takes as input a CPU mask which is not adequate when we need to send an IPI to a CPU which is not represented in the kernel to GIC mapping. That is the case with the b.L switcher when GIC migration to the inbound CPU has not yet occurred. Signed-off-by: Nicolas Pitre --- drivers/irqchip/irq-gic.c | 14 ++++++++++++++ include/linux/irqchip/arm-gic.h | 1 + 2 files changed, 15 insertions(+) (limited to 'include') diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c index 09fdf3d574cd..9031171c141b 100644 --- a/drivers/irqchip/irq-gic.c +++ b/drivers/irqchip/irq-gic.c @@ -673,6 +673,20 @@ void gic_raise_softirq(const struct cpumask *mask, unsigned int irq) #endif #ifdef CONFIG_BL_SWITCHER +/* + * gic_send_sgi - send a SGI directly to given CPU interface number + * + * cpu_id: the ID for the destination CPU interface + * irq: the IPI number to send a SGI for + */ +void gic_send_sgi(unsigned int cpu_id, unsigned int irq) +{ + BUG_ON(cpu_id >= NR_GIC_CPU_IF); + cpu_id = 1 << cpu_id; + /* this always happens on GIC0 */ + writel_relaxed((cpu_id << 16) | irq, gic_data_dist_base(&gic_data[0]) + GIC_DIST_SOFTINT); +} + /* * gic_get_cpu_id - get the CPU interface ID for the specified CPU * diff --git a/include/linux/irqchip/arm-gic.h b/include/linux/irqchip/arm-gic.h index dc30835099e3..cac496b1e279 100644 --- a/include/linux/irqchip/arm-gic.h +++ b/include/linux/irqchip/arm-gic.h @@ -76,6 +76,7 @@ static inline void gic_init(unsigned int nr, int start, gic_init_bases(nr, start, dist, cpu, 0, NULL); } +void gic_send_sgi(unsigned int cpu_id, unsigned int irq); int gic_get_cpu_id(unsigned int cpu); void gic_migrate_target(unsigned int new_cpu_id); unsigned long gic_get_sgir_physaddr(void); -- cgit v1.2.3 From 1bfbddb6f3a0dbb8c3996d1c4d4911d695737c15 Mon Sep 17 00:00:00 2001 From: Dave Martin Date: Mon, 14 May 2012 17:40:07 +0100 Subject: ARM: bL_switcher: Basic trace events support This patch adds simple trace events to the b.L switcher code to allow tracing of CPU migration events. To make use of the trace events, you will need: CONFIG_FTRACE=y CONFIG_ENABLE_DEFAULT_TRACERS=y The following events are added: * power:cpu_migrate_begin * power:cpu_migrate_finish each with the following data: u64 timestamp; u32 cpu_hwid; power:cpu_migrate_begin occurs immediately before the switcher-specific migration operations start. power:cpu_migrate_finish occurs immediately when migration is completed. The cpu_hwid field contains the ID fields of the MPIDR. * For power:cpu_migrate_begin, cpu_hwid is the ID of the outbound physical CPU (equivalent to (from_phys_cpu,from_phys_cluster)). * For power:cpu_migrate_finish, cpu_hwid is the ID of the inbound physical CPU (equivalent to (to_phys_cpu,to_phys_cluster)). By design, the cpu_hwid field is masked in the same way as the device tree cpu node reg property, allowing direct correlation to the DT description of the hardware. The timestamp is added in order to minimise timing noise. An accurate system-wide clock should be used for generating this (hopefully getnstimeofday is appropriate, but it could be changed). It could be any monotonic shared clock, since the aim is to allow accurate deltas to be computed. We don't necessarily care about accurate synchronisation with wall clock time. In practice, each switch takes place on a single logical CPU, and the trace infrastructure should guarantee that events are well-ordered with respect to a single logical CPU. Signed-off-by: Dave Martin Signed-off-by: Nicolas Pitre --- arch/arm/common/bL_switcher.c | 17 ++++++++ include/trace/events/power_cpu_migrate.h | 66 ++++++++++++++++++++++++++++++++ 2 files changed, 83 insertions(+) create mode 100644 include/trace/events/power_cpu_migrate.h (limited to 'include') diff --git a/arch/arm/common/bL_switcher.c b/arch/arm/common/bL_switcher.c index dc53eb8dcc81..7002de360d23 100644 --- a/arch/arm/common/bL_switcher.c +++ b/arch/arm/common/bL_switcher.c @@ -20,6 +20,7 @@ #include #include #include +#include #include #include #include @@ -33,10 +34,14 @@ #include #include +#include #include #include #include +#define CREATE_TRACE_POINTS +#include + /* * Use our own MPIDR accessors as the generic ones in asm/cputype.h have @@ -51,6 +56,16 @@ static int read_mpidr(void) return id & MPIDR_HWID_BITMASK; } +/* + * Get a global nanosecond time stamp for tracing. + */ +static s64 get_ns(void) +{ + struct timespec ts; + getnstimeofday(&ts); + return timespec_to_ns(&ts); +} + /* * bL switcher core code. */ @@ -208,6 +223,7 @@ static int bL_switch_to(unsigned int new_cluster_id) */ local_irq_disable(); local_fiq_disable(); + trace_cpu_migrate_begin(get_ns(), ob_mpidr); /* redirect GIC's SGIs to our counterpart */ gic_migrate_target(bL_gic_id[ib_cpu][ib_cluster]); @@ -250,6 +266,7 @@ static int bL_switch_to(unsigned int new_cluster_id) tdev->evtdev->next_event, 1); } + trace_cpu_migrate_finish(get_ns(), ib_mpidr); local_fiq_enable(); local_irq_enable(); diff --git a/include/trace/events/power_cpu_migrate.h b/include/trace/events/power_cpu_migrate.h new file mode 100644 index 000000000000..3694af0f5bc5 --- /dev/null +++ b/include/trace/events/power_cpu_migrate.h @@ -0,0 +1,66 @@ +#undef TRACE_SYSTEM +#define TRACE_SYSTEM power + +#if !defined(_TRACE_POWER_CPU_MIGRATE_H) || defined(TRACE_HEADER_MULTI_READ) +#define _TRACE_POWER_CPU_MIGRATE_H + +#include + +#define __cpu_migrate_proto \ + TP_PROTO(u64 timestamp, \ + u32 cpu_hwid) +#define __cpu_migrate_args \ + TP_ARGS(timestamp, \ + cpu_hwid) + +DECLARE_EVENT_CLASS(cpu_migrate, + + __cpu_migrate_proto, + __cpu_migrate_args, + + TP_STRUCT__entry( + __field(u64, timestamp ) + __field(u32, cpu_hwid ) + ), + + TP_fast_assign( + __entry->timestamp = timestamp; + __entry->cpu_hwid = cpu_hwid; + ), + + TP_printk("timestamp=%llu cpu_hwid=0x%08lX", + (unsigned long long)__entry->timestamp, + (unsigned long)__entry->cpu_hwid + ) +); + +#define __define_cpu_migrate_event(name) \ + DEFINE_EVENT(cpu_migrate, cpu_migrate_##name, \ + __cpu_migrate_proto, \ + __cpu_migrate_args \ + ) + +__define_cpu_migrate_event(begin); +__define_cpu_migrate_event(finish); + +#undef __define_cpu_migrate +#undef __cpu_migrate_proto +#undef __cpu_migrate_args + +/* This file can get included multiple times, TRACE_HEADER_MULTI_READ at top */ +#ifndef _PWR_CPU_MIGRATE_EVENT_AVOID_DOUBLE_DEFINING +#define _PWR_CPU_MIGRATE_EVENT_AVOID_DOUBLE_DEFINING + +/* + * Set from_phys_cpu and to_phys_cpu to CPU_MIGRATE_ALL_CPUS to indicate + * a whole-cluster migration: + */ +#define CPU_MIGRATE_ALL_CPUS 0x80000000U +#endif + +#endif /* _TRACE_POWER_CPU_MIGRATE_H */ + +/* This part must be outside protection */ +#undef TRACE_INCLUDE_FILE +#define TRACE_INCLUDE_FILE power_cpu_migrate +#include -- cgit v1.2.3 From b09bbe5b1267b6af22a9584d614f5eec5d74f405 Mon Sep 17 00:00:00 2001 From: Dave Martin Date: Wed, 6 Feb 2013 15:45:23 +0000 Subject: ARM: bL_switcher/trace: Add trace trigger for trace bootstrapping When tracing switching, an external tracer needs a way to bootstrap its knowledge of the logical<->physical CPU mapping. This patch adds a sysfs attribute trace_trigger. A write to this attribute will generate a power:cpu_migrate_current event for each online CPU, indicating the current physical CPU for each logical CPU. Activating or deactivating the switcher also generates these events, so that the tracer knows about the resulting remapping of affected CPUs. Signed-off-by: Dave Martin --- arch/arm/common/bL_switcher.c | 36 ++++++++++++++++++++++++++++++++ include/trace/events/power_cpu_migrate.h | 1 + 2 files changed, 37 insertions(+) (limited to 'include') diff --git a/arch/arm/common/bL_switcher.c b/arch/arm/common/bL_switcher.c index 7002de360d23..f0dc025077d5 100644 --- a/arch/arm/common/bL_switcher.c +++ b/arch/arm/common/bL_switcher.c @@ -27,6 +27,7 @@ #include #include #include +#include #include #include #include @@ -531,6 +532,25 @@ static int bL_switcher_halve_cpus(void) return 0; } +static void bL_switcher_trace_trigger_cpu(void *__always_unused info) +{ + trace_cpu_migrate_current(get_ns(), read_mpidr()); +} + +static int bL_switcher_trace_trigger(void) +{ + int ret; + + preempt_disable(); + + bL_switcher_trace_trigger_cpu(NULL); + ret = smp_call_function(bL_switcher_trace_trigger_cpu, NULL, true); + + preempt_enable(); + + return ret; +} + static int bL_switcher_enable(void) { int cpu, ret; @@ -553,6 +573,8 @@ static int bL_switcher_enable(void) if (ret) goto error; + bL_switcher_trace_trigger(); + for_each_online_cpu(cpu) { struct bL_thread *t = &bL_threads[cpu]; spin_lock_init(&t->lock); @@ -637,6 +659,8 @@ static void bL_switcher_disable(void) } bL_switcher_restore_cpus(); + bL_switcher_trace_trigger(); + bL_activation_notify(BL_NOTIFY_POST_DISABLE); out: @@ -670,11 +694,23 @@ static ssize_t bL_switcher_active_store(struct kobject *kobj, return (ret >= 0) ? count : ret; } +static ssize_t bL_switcher_trace_trigger_store(struct kobject *kobj, + struct kobj_attribute *attr, const char *buf, size_t count) +{ + int ret = bL_switcher_trace_trigger(); + + return ret ? ret : count; +} + static struct kobj_attribute bL_switcher_active_attr = __ATTR(active, 0644, bL_switcher_active_show, bL_switcher_active_store); +static struct kobj_attribute bL_switcher_trace_trigger_attr = + __ATTR(trace_trigger, 0200, NULL, bL_switcher_trace_trigger_store); + static struct attribute *bL_switcher_attrs[] = { &bL_switcher_active_attr.attr, + &bL_switcher_trace_trigger_attr.attr, NULL, }; diff --git a/include/trace/events/power_cpu_migrate.h b/include/trace/events/power_cpu_migrate.h index 3694af0f5bc5..f76dd4de625e 100644 --- a/include/trace/events/power_cpu_migrate.h +++ b/include/trace/events/power_cpu_migrate.h @@ -42,6 +42,7 @@ DECLARE_EVENT_CLASS(cpu_migrate, __define_cpu_migrate_event(begin); __define_cpu_migrate_event(finish); +__define_cpu_migrate_event(current); #undef __define_cpu_migrate #undef __cpu_migrate_proto -- cgit v1.2.3