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157 lines
3.1 KiB
157 lines
3.1 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/** |
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* @file nmi_timer_int.c |
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* |
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* @remark Copyright 2011 Advanced Micro Devices, Inc. |
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* |
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* @author Robert Richter <[email protected]> |
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*/ |
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#include <linux/init.h> |
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#include <linux/smp.h> |
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#include <linux/errno.h> |
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#include <linux/oprofile.h> |
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#include <linux/perf_event.h> |
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#ifdef CONFIG_OPROFILE_NMI_TIMER |
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static DEFINE_PER_CPU(struct perf_event *, nmi_timer_events); |
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static int ctr_running; |
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static struct perf_event_attr nmi_timer_attr = { |
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.type = PERF_TYPE_HARDWARE, |
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.config = PERF_COUNT_HW_CPU_CYCLES, |
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.size = sizeof(struct perf_event_attr), |
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.pinned = 1, |
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.disabled = 1, |
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}; |
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static void nmi_timer_callback(struct perf_event *event, |
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struct perf_sample_data *data, |
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struct pt_regs *regs) |
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{ |
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event->hw.interrupts = 0; /* don't throttle interrupts */ |
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oprofile_add_sample(regs, 0); |
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} |
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static int nmi_timer_start_cpu(int cpu) |
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{ |
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struct perf_event *event = per_cpu(nmi_timer_events, cpu); |
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if (!event) { |
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event = perf_event_create_kernel_counter(&nmi_timer_attr, cpu, NULL, |
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nmi_timer_callback, NULL); |
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if (IS_ERR(event)) |
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return PTR_ERR(event); |
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per_cpu(nmi_timer_events, cpu) = event; |
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} |
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if (event && ctr_running) |
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perf_event_enable(event); |
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return 0; |
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} |
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static void nmi_timer_stop_cpu(int cpu) |
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{ |
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struct perf_event *event = per_cpu(nmi_timer_events, cpu); |
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if (event && ctr_running) |
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perf_event_disable(event); |
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} |
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static int nmi_timer_cpu_online(unsigned int cpu) |
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{ |
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nmi_timer_start_cpu(cpu); |
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return 0; |
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} |
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static int nmi_timer_cpu_predown(unsigned int cpu) |
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{ |
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nmi_timer_stop_cpu(cpu); |
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return 0; |
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} |
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static int nmi_timer_start(void) |
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{ |
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int cpu; |
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get_online_cpus(); |
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ctr_running = 1; |
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for_each_online_cpu(cpu) |
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nmi_timer_start_cpu(cpu); |
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put_online_cpus(); |
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return 0; |
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} |
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static void nmi_timer_stop(void) |
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{ |
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int cpu; |
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get_online_cpus(); |
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for_each_online_cpu(cpu) |
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nmi_timer_stop_cpu(cpu); |
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ctr_running = 0; |
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put_online_cpus(); |
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} |
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static enum cpuhp_state hp_online; |
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static void nmi_timer_shutdown(void) |
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{ |
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struct perf_event *event; |
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int cpu; |
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cpuhp_remove_state(hp_online); |
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for_each_possible_cpu(cpu) { |
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event = per_cpu(nmi_timer_events, cpu); |
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if (!event) |
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continue; |
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perf_event_disable(event); |
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per_cpu(nmi_timer_events, cpu) = NULL; |
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perf_event_release_kernel(event); |
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} |
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} |
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static int nmi_timer_setup(void) |
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{ |
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int err; |
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u64 period; |
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/* clock cycles per tick: */ |
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period = (u64)cpu_khz * 1000; |
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do_div(period, HZ); |
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nmi_timer_attr.sample_period = period; |
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err = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "oprofile/nmi:online", |
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nmi_timer_cpu_online, nmi_timer_cpu_predown); |
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if (err < 0) { |
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nmi_timer_shutdown(); |
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return err; |
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} |
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hp_online = err; |
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return 0; |
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} |
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int __init op_nmi_timer_init(struct oprofile_operations *ops) |
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{ |
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int err = 0; |
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err = nmi_timer_setup(); |
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if (err) |
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return err; |
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nmi_timer_shutdown(); /* only check, don't alloc */ |
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ops->create_files = NULL; |
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ops->setup = nmi_timer_setup; |
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ops->shutdown = nmi_timer_shutdown; |
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ops->start = nmi_timer_start; |
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ops->stop = nmi_timer_stop; |
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ops->cpu_type = "timer"; |
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printk(KERN_INFO "oprofile: using NMI timer interrupt.\n"); |
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return 0; |
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} |
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#endif
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