cregit-Linux how code gets into the kernel

Release 4.7 arch/x86/events/msr.c

Directory: arch/x86/events
#include <linux/perf_event.h>


enum perf_msr_id {
	
PERF_MSR_TSC			= 0,
	
PERF_MSR_APERF			= 1,
	
PERF_MSR_MPERF			= 2,
	
PERF_MSR_PPERF			= 3,
	
PERF_MSR_SMI			= 4,
	
PERF_MSR_PTSC			= 5,
	
PERF_MSR_IRPERF			= 6,

	
PERF_MSR_EVENT_MAX,
};


static bool test_aperfmperf(int idx) { return boot_cpu_has(X86_FEATURE_APERFMPERF); }

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static bool test_ptsc(int idx) { return boot_cpu_has(X86_FEATURE_PTSC); }

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static bool test_irperf(int idx) { return boot_cpu_has(X86_FEATURE_IRPERF); }

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static bool test_intel(int idx) { if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL || boot_cpu_data.x86 != 6) return false; switch (boot_cpu_data.x86_model) { case 30: /* 45nm Nehalem */ case 26: /* 45nm Nehalem-EP */ case 46: /* 45nm Nehalem-EX */ case 37: /* 32nm Westmere */ case 44: /* 32nm Westmere-EP */ case 47: /* 32nm Westmere-EX */ case 42: /* 32nm SandyBridge */ case 45: /* 32nm SandyBridge-E/EN/EP */ case 58: /* 22nm IvyBridge */ case 62: /* 22nm IvyBridge-EP/EX */ case 60: /* 22nm Haswell Core */ case 63: /* 22nm Haswell Server */ case 69: /* 22nm Haswell ULT */ case 70: /* 22nm Haswell + GT3e (Intel Iris Pro graphics) */ case 61: /* 14nm Broadwell Core-M */ case 86: /* 14nm Broadwell Xeon D */ case 71: /* 14nm Broadwell + GT3e (Intel Iris Pro graphics) */ case 79: /* 14nm Broadwell Server */ case 55: /* 22nm Atom "Silvermont" */ case 77: /* 22nm Atom "Silvermont Avoton/Rangely" */ case 76: /* 14nm Atom "Airmont" */ if (idx == PERF_MSR_SMI) return true; break; case 78: /* 14nm Skylake Mobile */ case 94: /* 14nm Skylake Desktop */ if (idx == PERF_MSR_SMI || idx == PERF_MSR_PPERF) return true; break; } return false; }

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struct perf_msr { u64 msr; struct perf_pmu_events_attr *attr; bool (*test)(int idx); }; PMU_EVENT_ATTR_STRING(tsc, evattr_tsc, "event=0x00"); PMU_EVENT_ATTR_STRING(aperf, evattr_aperf, "event=0x01"); PMU_EVENT_ATTR_STRING(mperf, evattr_mperf, "event=0x02"); PMU_EVENT_ATTR_STRING(pperf, evattr_pperf, "event=0x03"); PMU_EVENT_ATTR_STRING(smi, evattr_smi, "event=0x04"); PMU_EVENT_ATTR_STRING(ptsc, evattr_ptsc, "event=0x05"); PMU_EVENT_ATTR_STRING(irperf, evattr_irperf, "event=0x06"); static struct perf_msr msr[] = { [PERF_MSR_TSC] = { 0, &evattr_tsc, NULL, }, [PERF_MSR_APERF] = { MSR_IA32_APERF, &evattr_aperf, test_aperfmperf, }, [PERF_MSR_MPERF] = { MSR_IA32_MPERF, &evattr_mperf, test_aperfmperf, }, [PERF_MSR_PPERF] = { MSR_PPERF, &evattr_pperf, test_intel, }, [PERF_MSR_SMI] = { MSR_SMI_COUNT, &evattr_smi, test_intel, }, [PERF_MSR_PTSC] = { MSR_F15H_PTSC, &evattr_ptsc, test_ptsc, }, [PERF_MSR_IRPERF] = { MSR_F17H_IRPERF, &evattr_irperf, test_irperf, }, }; static struct attribute *events_attrs[PERF_MSR_EVENT_MAX + 1] = { NULL, }; static struct attribute_group events_attr_group = { .name = "events", .attrs = events_attrs, }; PMU_FORMAT_ATTR(event, "config:0-63"); static struct attribute *format_attrs[] = { &format_attr_event.attr, NULL, }; static struct attribute_group format_attr_group = { .name = "format", .attrs = format_attrs, }; static const struct attribute_group *attr_groups[] = { &events_attr_group, &format_attr_group, NULL, };
static int msr_event_init(struct perf_event *event) { u64 cfg = event->attr.config; if (event->attr.type != event->pmu->type) return -ENOENT; if (cfg >= PERF_MSR_EVENT_MAX) return -EINVAL; /* unsupported modes and filters */ if (event->attr.exclude_user || event->attr.exclude_kernel || event->attr.exclude_hv || event->attr.exclude_idle || event->attr.exclude_host || event->attr.exclude_guest || event->attr.sample_period) /* no sampling */ return -EINVAL; if (!msr[cfg].attr) return -EINVAL; event->hw.idx = -1; event->hw.event_base = msr[cfg].msr; event->hw.config = cfg; return 0; }

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static inline u64 msr_read_counter(struct perf_event *event) { u64 now; if (event->hw.event_base) rdmsrl(event->hw.event_base, now); else rdtscll(now); return now; }

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static void msr_event_update(struct perf_event *event) { u64 prev, now; s64 delta; /* Careful, an NMI might modify the previous event value. */ again: prev = local64_read(&event->hw.prev_count); now = msr_read_counter(event); if (local64_cmpxchg(&event->hw.prev_count, prev, now) != prev) goto again; delta = now - prev; if (unlikely(event->hw.event_base == MSR_SMI_COUNT)) delta = sign_extend64(delta, 31); local64_add(delta, &event->count); }

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static void msr_event_start(struct perf_event *event, int flags) { u64 now; now = msr_read_counter(event); local64_set(&event->hw.prev_count, now); }

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static void msr_event_stop(struct perf_event *event, int flags) { msr_event_update(event); }

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static void msr_event_del(struct perf_event *event, int flags) { msr_event_stop(event, PERF_EF_UPDATE); }

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static int msr_event_add(struct perf_event *event, int flags) { if (flags & PERF_EF_START) msr_event_start(event, flags); return 0; }

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static struct pmu pmu_msr = { .task_ctx_nr = perf_sw_context, .attr_groups = attr_groups, .event_init = msr_event_init, .add = msr_event_add, .del = msr_event_del, .start = msr_event_start, .stop = msr_event_stop, .read = msr_event_update, .capabilities = PERF_PMU_CAP_NO_INTERRUPT, };
static int __init msr_init(void) { int i, j = 0; if (!boot_cpu_has(X86_FEATURE_TSC)) { pr_cont("no MSR PMU driver.\n"); return 0; } /* Probe the MSRs. */ for (i = PERF_MSR_TSC + 1; i < PERF_MSR_EVENT_MAX; i++) { u64 val; /* * Virt sucks arse; you cannot tell if a R/O MSR is present :/ */ if (!msr[i].test(i) || rdmsrl_safe(msr[i].msr, &val)) msr[i].attr = NULL; } /* List remaining MSRs in the sysfs attrs. */ for (i = 0; i < PERF_MSR_EVENT_MAX; i++) { if (msr[i].attr) events_attrs[j++] = &msr[i].attr->attr.attr; } events_attrs[j] = NULL; perf_pmu_register(&pmu_msr, "msr", -1); return 0; }

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device_initcall(msr_init);

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martin kepplingermartin kepplinger60.54%112.50%
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Directory: arch/x86/events
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