/* * Performance event support - powerpc architecture code * * Copyright 2008-2009 Paul Mackerras, IBM Corporation. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. */ #include #include #include #include #include #include #include #include #include #include struct cpu_hw_events { int n_events; int n_percpu; int disabled; int n_added; int n_limited; u8 pmcs_enabled; struct perf_event *event[MAX_HWEVENTS]; u64 events[MAX_HWEVENTS]; unsigned int flags[MAX_HWEVENTS]; unsigned long mmcr[3]; struct perf_event *limited_counter[MAX_LIMITED_HWCOUNTERS]; u8 limited_hwidx[MAX_LIMITED_HWCOUNTERS]; u64 alternatives[MAX_HWEVENTS][MAX_EVENT_ALTERNATIVES]; unsigned long amasks[MAX_HWEVENTS][MAX_EVENT_ALTERNATIVES]; unsigned long avalues[MAX_HWEVENTS][MAX_EVENT_ALTERNATIVES]; unsigned int group_flag; int n_txn_start; }; DEFINE_PER_CPU(struct cpu_hw_events, cpu_hw_events); struct power_pmu *ppmu; /* * Normally, to ignore kernel events we set the FCS (freeze counters * in supervisor mode) bit in MMCR0, but if the kernel runs with the * hypervisor bit set in the MSR, or if we are running on a processor * where the hypervisor bit is forced to 1 (as on Apple G5 processors), * then we need to use the FCHV bit to ignore kernel events. */ static unsigned int freeze_events_kernel = MMCR0_FCS; /* * 32-bit doesn't have MMCRA but does have an MMCR2, * and a few other names are different. */ #ifdef CONFIG_PPC32 #define MMCR0_FCHV 0 #define MMCR0_PMCjCE MMCR0_PMCnCE #define SPRN_MMCRA SPRN_MMCR2 #define MMCRA_SAMPLE_ENABLE 0 static inline unsigned long perf_ip_adjust(struct pt_regs *regs) { return 0; } static inline void perf_get_data_addr(struct pt_regs *regs, u64 *addrp) { } static inline u32 perf_get_misc_flags(struct pt_regs *regs) { return 0; } static inline void perf_read_regs(struct pt_regs *regs) { regs->result = 0; } static inline int perf_intr_is_nmi(struct pt_regs *regs) { return 0; } static inline int siar_valid(struct pt_regs *regs) { return 1; } #endif /* CONFIG_PPC32 */ static bool regs_use_siar(struct pt_regs *regs) { return !!(regs->result & 1); } /* * Things that are specific to 64-bit implementations. */ #ifdef CONFIG_PPC64 static inline unsigned long perf_ip_adjust(struct pt_regs *regs) { unsigned long mmcra = regs->dsisr; if ((ppmu->flags & PPMU_HAS_SSLOT) && (mmcra & MMCRA_SAMPLE_ENABLE)) { unsigned long slot = (mmcra & MMCRA_SLOT) >> MMCRA_SLOT_SHIFT; if (slot > 1) return 4 * (slot - 1); } return 0; } /* * The user wants a data address recorded. * If we're not doing instruction sampling, give them the SDAR * (sampled data address). If we are doing instruction sampling, then * only give them the SDAR if it corresponds to the instruction * pointed to by SIAR; this is indicated by the [POWER6_]MMCRA_SDSYNC or * the [POWER7P_]MMCRA_SDAR_VALID bit in MMCRA. */ static inline void perf_get_data_addr(struct pt_regs *regs, u64 *addrp) { unsigned long mmcra = regs->dsisr; unsigned long sdsync; if (ppmu->flags & PPMU_SIAR_VALID) sdsync = POWER7P_MMCRA_SDAR_VALID; else if (ppmu->flags & PPMU_ALT_SIPR) sdsync = POWER6_MMCRA_SDSYNC; else sdsync = MMCRA_SDSYNC; if (!(mmcra & MMCRA_SAMPLE_ENABLE) || (mmcra & sdsync)) *addrp = mfspr(SPRN_SDAR); } static bool regs_sihv(struct pt_regs *regs) { unsigned long sihv = MMCRA_SIHV; if (ppmu->flags & PPMU_ALT_SIPR) sihv = POWER6_MMCRA_SIHV; return !!(regs->dsisr & sihv); } static bool regs_sipr(struct pt_regs *regs) { unsigned long sipr = MMCRA_SIPR; if (ppmu->flags & PPMU_ALT_SIPR) sipr = POWER6_MMCRA_SIPR; return !!(regs->dsisr & sipr); } static inline u32 perf_flags_from_msr(struct pt_regs *regs) { if (regs->msr & MSR_PR) return PERF_RECORD_MISC_USER; if ((regs->msr & MSR_HV) && freeze_events_kernel != MMCR0_FCHV) return PERF_RECORD_MISC_HYPERVISOR; return PERF_RECORD_MISC_KERNEL; } static inline u32 perf_get_misc_flags(struct pt_regs *regs) { bool use_siar = regs_use_siar(regs); if (!use_siar) return perf_flags_from_msr(regs); /* * If we don't have flags in MMCRA, rather than using * the MSR, we intuit the flags from the address in * SIAR which should give slightly more reliable * results */ if (ppmu->flags & PPMU_NO_SIPR) { unsigned long siar = mfspr(SPRN_SIAR); if (siar >= PAGE_OFFSET) return PERF_RECORD_MISC_KERNEL; return PERF_RECORD_MISC_USER; } /* PR has priority over HV, so order below is important */ if (regs_sipr(regs)) return PERF_RECORD_MISC_USER; if (regs_sihv(regs) && (freeze_events_kernel != MMCR0_FCHV)) return PERF_RECORD_MISC_HYPERVISOR; return PERF_RECORD_MISC_KERNEL; } /* * Overload regs->dsisr to store MMCRA so we only need to read it once * on each interrupt. * Overload regs->result to specify whether we should use the MSR (result * is zero) or the SIAR (result is non zero). */ static inline void perf_read_regs(struct pt_regs *regs) { unsigned long mmcra = mfspr(SPRN_MMCRA); int marked = mmcra & MMCRA_SAMPLE_ENABLE; int use_siar; regs->dsisr = mmcra; /* * If this isn't a PMU exception (eg a software event) the SIAR is * not valid. Use pt_regs. * * If it is a marked event use the SIAR. * * If the PMU doesn't update the SIAR for non marked events use * pt_regs. * * If the PMU has HV/PR flags then check to see if they * place the exception in userspace. If so, use pt_regs. In * continuous sampling mode the SIAR and the PMU exception are * not synchronised, so they may be many instructions apart. * This can result in confusing backtraces. We still want * hypervisor samples as well as samples in the kernel with * interrupts off hence the userspace check. */ if (TRAP(regs) != 0xf00) use_siar = 0; else if (marked) use_siar = 1; else if ((ppmu->flags & PPMU_NO_CONT_SAMPLING)) use_siar = 0; else if (!(ppmu->flags & PPMU_NO_SIPR) && regs_sipr(regs)) use_siar = 0; else use_siar = 1; regs->result = use_siar; } /* * If interrupts were soft-disabled when a PMU interrupt occurs, treat * it as an NMI. */ static inline int perf_intr_is_nmi(struct pt_regs *regs) { return !regs->softe; } /* * On processors like P7+ that have the SIAR-Valid bit, marked instructions * must be sampled only if the SIAR-valid bit is set. * * For unmarked instructions and for processors that don't have the SIAR-Valid * bit, assume that SIAR is valid. */ static inline int siar_valid(struct pt_regs *regs) { unsigned long mmcra = regs->dsisr; int marked = mmcra & MMCRA_SAMPLE_ENABLE; if ((ppmu->flags & PPMU_SIAR_VALID) && marked) return mmcra & POWER7P_MMCRA_SIAR_VALID; return 1; } #endif /* CONFIG_PPC64 */ static void perf_event_interrupt(struct pt_regs *regs); void perf_event_print_debug(void) { } /* * Read one performance monitor counter (PMC). */ static unsigned long read_pmc(int idx) { unsigned long val; switch (idx) { case 1: val = mfspr(SPRN_PMC1); break; case 2: val = mfspr(SPRN_PMC2); break; case 3: val = mfspr(SPRN_PMC3); break; case 4: val = mfspr(SPRN_PMC4); break; case 5: val = mfspr(SPRN_PMC5); break; case 6: val = mfspr(SPRN_PMC6); break; #ifdef CONFIG_PPC64 case 7: val = mfspr(SPRN_PMC7); break; case 8: val = mfspr(SPRN_PMC8); break; #endif /* CONFIG_PPC64 */ default: printk(KERN_ERR "oops trying to read PMC%d\n", idx); val = 0; } return val; } /* * Write one PMC. */ static void write_pmc(int idx, unsigned long val) { switch (idx) { case 1: mtspr(SPRN_PMC1, val); break; case 2: mtspr(SPRN_PMC2, val); break; case 3: mtspr(SPRN_PMC3, val); break; case 4: mtspr(SPRN_PMC4, val); break; case 5: mtspr(SPRN_PMC5, val); break; case 6: mtspr(SPRN_PMC6, val); break; #ifdef CONFIG_PPC64 case 7: mtspr(SPRN_PMC7, val); break; case 8: mtspr(SPRN_PMC8, val); break; #endif /* CONFIG_PPC64 */ default: printk(KERN_ERR "oops trying to write PMC%d\n", idx); } } /* * Check if a set of events can all go on the PMU at once. * If they can't, this will look at alternative codes for the events * and see if any combination of alternative codes is feasible. * The feasible set is returned in event_id[]. */ static int power_check_constraints(struct cpu_hw_events *cpuhw, u64 event_id[], unsigned int cflags[], int n_ev) { unsigned long mask, value, nv; unsigned long smasks[MAX_HWEVENTS], svalues[MAX_HWEVENTS]; int n_alt[MAX_HWEVENTS], choice[MAX_HWEVENTS]; int i, j; unsigned long addf = ppmu->add_fields; unsigned long tadd = ppmu->test_adder; if (n_ev > ppmu->n_counter) return -1; /* First see if the events will go on as-is */ for (i = 0; i < n_ev; ++i) { if ((cflags[i] & PPMU_LIMITED_PMC_REQD) && !ppmu->limited_pmc_event(event_id[i])) { ppmu->get_alternatives(event_id[i], cflags[i], cpuhw->alternatives[i]); event_id[i] = cpuhw->alternatives[i][0]; } if (ppmu->get_constraint(event_id[i], &cpuhw->amasks[i][0], &cpuhw->avalues[i][0])) return -1; } value = mask = 0; for (i = 0; i < n_ev; ++i) { nv = (value | cpuhw->avalues[i][0]) + (value & cpuhw->avalues[i][0] & addf); if ((((nv + tadd) ^ value) & mask) != 0 || (((nv + tadd) ^ cpuhw->avalues[i][0]) & cpuhw->amasks[i][0]) != 0) break; value = nv; mask |= cpuhw->amasks[i][0]; } if (i == n_ev) return 0; /* all OK */ /* doesn't work, gather alternatives... */ if (!ppmu->get_alternatives) return -1; for (i = 0; i < n_ev; ++i) { choice[i] = 0; n_alt[i] = ppmu->get_alternatives(event_id[i], cflags[i], cpuhw->alternatives[i]); for (j = 1; j < n_alt[i]; ++j) ppmu->get_constraint(cpuhw->alternatives[i][j], &cpuhw->amasks[i][j], &cpuhw->avalues[i][j]); } /* enumerate all possibilities and see if any will work */ i = 0; j = -1; value = mask = nv = 0; while (i < n_ev) { if (j >= 0) { /* we're backtracking, restore context */ value = svalues[i]; mask = smasks[i]; j = choice[i]; } /* * See if any alternative k for event_id i, * where k > j, will satisfy the constraints. */ while (++j < n_alt[i]) { nv = (value | cpuhw->avalues[i][j]) + (value & cpuhw->avalues[i][j] & addf); if ((((nv + tadd) ^ value) & mask) == 0 && (((nv + tadd) ^ cpuhw->avalues[i][j]) & cpuhw->amasks[i][j]) == 0) break; } if (j >= n_alt[i]) { /* * No feasible alternative, backtrack * to event_id i-1 and continue enumerating its * alternatives from where we got up to. */ if (--i < 0) return -1; } else { /* * Found a feasible alternative for event_id i, * remember where we got up to with this event_id, * go on to the next event_id, and start with * the first alternative for it. */ choice[i] = j; svalues[i] = value; smasks[i] = mask; value = nv; mask |= cpuhw->amasks[i][j]; ++i; j = -1; } } /* OK, we have a feasible combination, tell the caller the solution */ for (i = 0; i < n_ev; ++i) event_id[i] = cpuhw->alternatives[i][choice[i]]; return 0; } /* * Check if newly-added events have consistent settings for * exclude_{user,kernel,hv} with each other and any previously * added events. */ static int check_excludes(struct perf_event **ctrs, unsigned int cflags[], int n_prev, int n_new) { int eu = 0, ek = 0, eh = 0; int i, n, first; struct perf_event *event; n = n_prev + n_new; if (n <= 1) return 0; first = 1; for (i = 0; i < n; ++i) { if (cflags[i] & PPMU_LIMITED_PMC_OK) { cflags[i] &= ~PPMU_LIMITED_PMC_REQD; continue; } event = ctrs[i]; if (first) { eu = event->attr.exclude_user; ek = event->attr.exclude_kernel; eh = event->attr.exclude_hv; first = 0; } else if (event->attr.exclude_user != eu || event->attr.exclude_kernel != ek || event->attr.exclude_hv != eh) { return -EAGAIN; } } if (eu || ek || eh) for (i = 0; i < n; ++i) if (cflags[i] & PPMU_LIMITED_PMC_OK) cflags[i] |= PPMU_LIMITED_PMC_REQD; return 0; } static u64 check_and_compute_delta(u64 prev, u64 val) { u64 delta = (val - prev) & 0xfffffffful; /* * POWER7 can roll back counter values, if the new value is smaller * than the previous value it will cause the delta and the counter to * have bogus values unless we rolled a counter over. If a coutner is * rolled back, it will be smaller, but within 256, which is the maximum * number of events to rollback at once. If we dectect a rollback * return 0. This can lead to a small lack of precision in the * counters. */ if (prev > val && (prev - val) < 256) delta = 0; return delta; } static void power_pmu_read(struct perf_event *event) { s64 val, delta, prev; if (event->hw.state & PERF_HES_STOPPED) return; if (!event->hw.idx) return; /* * Performance monitor interrupts come even when interrupts * are soft-disabled, as long as interrupts are hard-enabled. * Therefore we treat them like NMIs. */ do { prev = local64_read(&event->hw.prev_count); barrier(); val = read_pmc(event->hw.idx); delta = check_and_compute_delta(prev, val); if (!delta) return; } while (local64_cmpxchg(&event->hw.prev_count, prev, val) != prev); local64_add(delta, &event->count); local64_sub(delta, &event->hw.period_left); } /* * On some machines, PMC5 and PMC6 can't be written, don't respect * the freeze conditions, and don't generate interrupts. This tells * us if `event' is using such a PMC. */ static int is_limited_pmc(int pmcnum) { return (ppmu->flags & PPMU_LIMITED_PMC5_6) && (pmcnum == 5 || pmcnum == 6); } static void freeze_limited_counters(struct cpu_hw_events *cpuhw, unsigned long pmc5, unsigned long pmc6) { struct perf_event *event; u64 val, prev, delta; int i; for (i = 0; i < cpuhw->n_limited; ++i) { event = cpuhw->limited_counter[i]; if (!event->hw.idx) continue; val = (event->hw.idx == 5) ? pmc5 : pmc6; prev = local64_read(&event->hw.prev_count); event->hw.idx = 0; delta = check_and_compute_delta(prev, val); if (delta) local64_add(delta, &event->count); } } static void thaw_limited_counters(struct cpu_hw_events *cpuhw, unsigned long pmc5, unsigned long pmc6) { struct perf_event *event; u64 val, prev; int i; for (i = 0; i < cpuhw->n_limited; ++i) { event = cpuhw->limited_counter[i]; event->hw.idx = cpuhw->limited_hwidx[i]; val = (event->hw.idx == 5) ? pmc5 : pmc6; prev = local64_read(&event->hw.prev_count); if (check_and_compute_delta(prev, val)) local64_set(&event->hw.prev_count, val); perf_event_update_userpage(event); } } /* * Since limited events don't respect the freeze conditions, we * have to read them immediately after freezing or unfreezing the * other events. We try to keep the values from the limited * events as consistent as possible by keeping the delay (in * cycles and instructions) between freezing/unfreezing and reading * the limited events as small and consistent as possible. * Therefore, if any limited events are in use, we read them * both, and always in the same order, to minimize variability, * and do it inside the same asm that writes MMCR0. */ static void write_mmcr0(struct cpu_hw_events *cpuhw, unsigned long mmcr0) { unsigned long pmc5, pmc6; if (!cpuhw->n_limited) { mtspr(SPRN_MMCR0, mmcr0); return; } /* * Write MMCR0, then read PMC5 and PMC6 immediately. * To ensure we don't get a performance monitor interrupt * between writing MMCR0 and freezing/thawing the limited * events, we first write MMCR0 with the event overflow * interrupt enable bits turned off. */ asm volatile("mtspr %3,%2; mfspr %0,%4; mfspr %1,%5" : "=&r" (pmc5), "=&r" (pmc6) : "r" (mmcr0 & ~(MMCR0_PMC1CE | MMCR0_PMCjCE)), "i" (SPRN_MMCR0), "i" (SPRN_PMC5), "i" (SPRN_PMC6)); if (mmcr0 & MMCR0_FC) freeze_limited_counters(cpuhw, pmc5, pmc6); else thaw_limited_counters(cpuhw, pmc5, pmc6); /* * Write the full MMCR0 including the event overflow interrupt * enable bits, if necessary. */ if (mmcr0 & (MMCR0_PMC1CE | MMCR0_PMCjCE)) mtspr(SPRN_MMCR0, mmcr0); } /* * Disable all events to prevent PMU interrupts and to allow * events to be added or removed. */ static void power_pmu_disable(struct pmu *pmu) { struct cpu_hw_events *cpuhw; unsigned long flags; if (!ppmu) return; local_irq_save(flags); cpuhw = &__get_cpu_var(cpu_hw_events); if (!cpuhw->disabled) { cpuhw->disabled = 1; cpuhw->n_added = 0; /* * Check if we ever enabled the PMU on this cpu. */ if (!cpuhw->pmcs_enabled) { ppc_enable_pmcs(); cpuhw->pmcs_enabled = 1; } /* * Disable instruction sampling if it was enabled */ if (cpuhw->mmcr[2] & MMCRA_SAMPLE_ENABLE) { mtspr(SPRN_MMCRA, cpuhw->mmcr[2] & ~MMCRA_SAMPLE_ENABLE); mb(); } /* * Set the 'freeze counters' bit. * The barrier is to make sure the mtspr has been * executed and the PMU has frozen the events * before we return. */ write_mmcr0(cpuhw, mfspr(SPRN_MMCR0) | MMCR0_FC); mb(); } local_irq_restore(flags); } /* * Re-enable all events if disable == 0. * If we were previously disabled and events were added, then * put the new config on the PMU. */ static void power_pmu_enable(struct pmu *pmu) { struct perf_event *event; struct cpu_hw_events *cpuhw; unsigned long flags; long i; unsigned long val; s64 left; unsigned int hwc_index[MAX_HWEVENTS]; int n_lim; int idx; if (!ppmu) return; local_irq_save(flags); cpuhw = &__get_cpu_var(cpu_hw_events); if (!cpuhw->disabled) { local_irq_restore(flags); return; } cpuhw->disabled = 0; /* * If we didn't change anything, or only removed events, * no need to recalculate MMCR* settings and reset the PMCs. * Just reenable the PMU with the current MMCR* settings * (possibly updated for removal of events). */ if (!cpuhw->n_added) { mtspr(SPRN_MMCRA, cpuhw->mmcr[2] & ~MMCRA_SAMPLE_ENABLE); mtspr(SPRN_MMCR1, cpuhw->mmcr[1]); if (cpuhw->n_events == 0) ppc_set_pmu_inuse(0); goto out_enable; } /* * Compute MMCR* values for the new set of events */ if (ppmu->compute_mmcr(cpuhw->events, cpuhw->n_events, hwc_index, cpuhw->mmcr)) { /* shouldn't ever get here */ printk(KERN_ERR "oops compute_mmcr failed\n"); goto out; } /* * Add in MMCR0 freeze bits corresponding to the * attr.exclude_* bits for the first event. * We have already checked that all events have the * same values for these bits as the first event. */ event = cpuhw->event[0]; if (event->attr.exclude_user) cpuhw->mmcr[0] |= MMCR0_FCP; if (event->attr.exclude_kernel) cpuhw->mmcr[0] |= freeze_events_kernel; if (event->attr.exclude_hv) cpuhw->mmcr[0] |= MMCR0_FCHV; /* * Write the new configuration to MMCR* with the freeze * bit set and set the hardware events to their initial values. * Then unfreeze the events. */ ppc_set_pmu_inuse(1); mtspr(SPRN_MMCRA, cpuhw->mmcr[2] & ~MMCRA_SAMPLE_ENABLE); mtspr(SPRN_MMCR1, cpuhw->mmcr[1]); mtspr(SPRN_MMCR0, (cpuhw->mmcr[0] & ~(MMCR0_PMC1CE | MMCR0_PMCjCE)) | MMCR0_FC); /* * Read off any pre-existing events that need to move * to another PMC. */ for (i = 0; i < cpuhw->n_events; ++i) { event = cpuhw->event[i]; if (event->hw.idx && event->hw.idx != hwc_index[i] + 1) { power_pmu_read(event); write_pmc(event->hw.idx, 0); event->hw.idx = 0; } } /* * Initialize the PMCs for all the new and moved events. */ cpuhw->n_limited = n_lim = 0; for (i = 0; i < cpuhw->n_events; ++i) { event = cpuhw->event[i]; if (event->hw.idx) continue; idx = hwc_index[i] + 1; if (is_limited_pmc(idx)) { cpuhw->limited_counter[n_lim] = event; cpuhw->limited_hwidx[n_lim] = idx; ++n_lim; continue; } val = 0; if (event->hw.sample_period) { left = local64_read(&event->hw.period_left); if (left < 0x80000000L) val = 0x80000000L - left; } local64_set(&event->hw.prev_count, val); event->hw.idx = idx; if (event->hw.state & PERF_HES_STOPPED) val = 0; write_pmc(idx, val); perf_event_update_userpage(event); } cpuhw->n_limited = n_lim; cpuhw->mmcr[0] |= MMCR0_PMXE | MMCR0_FCECE; out_enable: mb(); write_mmcr0(cpuhw, cpuhw->mmcr[0]); /* * Enable instruction sampling if necessary */ if (cpuhw->mmcr[2] & MMCRA_SAMPLE_ENABLE) { mb(); mtspr(SPRN_MMCRA, cpuhw->mmcr[2]); } out: local_irq_restore(flags); } static int collect_events(struct perf_event *group, int max_count, struct perf_event *ctrs[], u64 *events, unsigned int *flags) { int n = 0; struct perf_event *event; if (!is_software_event(group)) { if (n >= max_count) return -1; ctrs[n] = group; flags[n] = group->hw.event_base; events[n++] = group->hw.config; } list_for_each_entry(event, &group->sibling_list, group_entry) { if (!is_software_event(event) && event->state != PERF_EVENT_STATE_OFF) { if (n >= max_count) return -1; ctrs[n] = event; flags[n] = event->hw.event_base; events[n++] = event->hw.config; } } return n; } /* * Add a event to the PMU. * If all events are not already frozen, then we disable and * re-enable the PMU in order to get hw_perf_enable to do the * actual work of reconfiguring the PMU. */ static int power_pmu_add(struct perf_event *event, int ef_flags) { struct cpu_hw_events *cpuhw; unsigned long flags; int n0; int ret = -EAGAIN; local_irq_save(flags); perf_pmu_disable(event->pmu); /* * Add the event to the list (if there is room) * and check whether the total set is still feasible. */ cpuhw = &__get_cpu_var(cpu_hw_events); n0 = cpuhw->n_events; if (n0 >= ppmu->n_counter) goto out; cpuhw->event[n0] = event; cpuhw->events[n0] = event->hw.config; cpuhw->flags[n0] = event->hw.event_base; /* * This event may have been disabled/stopped in record_and_restart() * because we exceeded the ->event_limit. If re-starting the event, * clear the ->hw.state (STOPPED and UPTODATE flags), so the user * notification is re-enabled. */ if (!(ef_flags & PERF_EF_START)) event->hw.state = PERF_HES_STOPPED | PERF_HES_UPTODATE; else event->hw.state = 0; /* * If group events scheduling transaction was started, * skip the schedulability test here, it will be performed * at commit time(->commit_txn) as a whole */ if (cpuhw->group_flag & PERF_EVENT_TXN) goto nocheck; if (check_excludes(cpuhw->event, cpuhw->flags, n0, 1)) goto out; if (power_check_constraints(cpuhw, cpuhw->events, cpuhw->flags, n0 + 1)) goto out; event->hw.config = cpuhw->events[n0]; nocheck: ++cpuhw->n_events; ++cpuhw->n_added; ret = 0; out: perf_pmu_enable(event->pmu); local_irq_restore(flags); return ret; } /* * Remove a event from the PMU. */ static void power_pmu_del(struct perf_event *event, int ef_flags) { struct cpu_hw_events *cpuhw; long i; unsigned long flags; local_irq_save(flags); perf_pmu_disable(event->pmu); power_pmu_read(event); cpuhw = &__get_cpu_var(cpu_hw_events); for (i = 0; i < cpuhw->n_events; ++i) { if (event == cpuhw->event[i]) { while (++i < cpuhw->n_events) { cpuhw->event[i-1] = cpuhw->event[i]; cpuhw->events[i-1] = cpuhw->events[i]; cpuhw->flags[i-1] = cpuhw->flags[i]; } --cpuhw->n_events; ppmu->disable_pmc(event->hw.idx - 1, cpuhw->mmcr); if (event->hw.idx) { write_pmc(event->hw.idx, 0); event->hw.idx = 0; } perf_event_update_userpage(event); break; } } for (i = 0; i < cpuhw->n_limited; ++i) if (event == cpuhw->limited_counter[i]) break; if (i < cpuhw->n_limited) { while (++i < cpuhw->n_limited) { cpuhw->limited_counter[i-1] = cpuhw->limited_counter[i]; cpuhw->limited_hwidx[i-1] = cpuhw->limited_hwidx[i]; } --cpuhw->n_limited; } if (cpuhw->n_events == 0) { /* disable exceptions if no events are running */ cpuhw->mmcr[0] &= ~(MMCR0_PMXE | MMCR0_FCECE); } perf_pmu_enable(event->pmu); local_irq_restore(flags); } /* * POWER-PMU does not support disabling individual counters, hence * program their cycle counter to their max value and ignore the interrupts. */ static void power_pmu_start(struct perf_event *event, int ef_flags) { unsigned long flags; s64 left; unsigned long val; if (!event->hw.idx || !event->hw.sample_period) return; if (!(event->hw.state & PERF_HES_STOPPED)) return; if (ef_flags & PERF_EF_RELOAD) WARN_ON_ONCE(!(event->hw.state & PERF_HES_UPTODATE)); local_irq_save(flags); perf_pmu_disable(event->pmu); event->hw.state = 0; left = local64_read(&event->hw.period_left); val = 0; if (left < 0x80000000L) val = 0x80000000L - left; write_pmc(event->hw.idx, val); perf_event_update_userpage(event); perf_pmu_enable(event->pmu); local_irq_restore(flags); } static void power_pmu_stop(struct perf_event *event, int ef_flags) { unsigned long flags; if (!event->hw.idx || !event->hw.sample_period) return; if (event->hw.state & PERF_HES_STOPPED) return; local_irq_save(flags); perf_pmu_disable(event->pmu); power_pmu_read(event); event->hw.state |= PERF_HES_STOPPED | PERF_HES_UPTODATE; write_pmc(event->hw.idx, 0); perf_event_update_userpage(event); perf_pmu_enable(event->pmu); local_irq_restore(flags); } /* * Start group events scheduling transaction * Set the flag to make pmu::enable() not perform the * schedulability test, it will be performed at commit time */ void power_pmu_start_txn(struct pmu *pmu) { struct cpu_hw_events *cpuhw = &__get_cpu_var(cpu_hw_events); perf_pmu_disable(pmu); cpuhw->group_flag |= PERF_EVENT_TXN; cpuhw->n_txn_start = cpuhw->n_events; } /* * Stop group events scheduling transaction * Clear the flag and pmu::enable() will perform the * schedulability test. */ void power_pmu_cancel_txn(struct pmu *pmu) { struct cpu_hw_events *cpuhw = &__get_cpu_var(cpu_hw_events); cpuhw->group_flag &= ~PERF_EVENT_TXN; perf_pmu_enable(pmu); } /* * Commit group events scheduling transaction * Perform the group schedulability test as a whole * Return 0 if success */ int power_pmu_commit_txn(struct pmu *pmu) { struct cpu_hw_events *cpuhw; long i, n; if (!ppmu) return -EAGAIN; cpuhw = &__get_cpu_var(cpu_hw_events); n = cpuhw->n_events; if (check_excludes(cpuhw->event, cpuhw->flags, 0, n)) return -EAGAIN; i = power_check_constraints(cpuhw, cpuhw->events, cpuhw->flags, n); if (i < 0) return -EAGAIN; for (i = cpuhw->n_txn_start; i < n; ++i) cpuhw->event[i]->hw.config = cpuhw->events[i]; cpuhw->group_flag &= ~PERF_EVENT_TXN; perf_pmu_enable(pmu); return 0; } /* * Return 1 if we might be able to put event on a limited PMC, * or 0 if not. * A event can only go on a limited PMC if it counts something * that a limited PMC can count, doesn't require interrupts, and * doesn't exclude any processor mode. */ static int can_go_on_limited_pmc(struct perf_event *event, u64 ev, unsigned int flags) { int n; u64 alt[MAX_EVENT_ALTERNATIVES]; if (event->attr.exclude_user || event->attr.exclude_kernel || event->attr.exclude_hv || event->attr.sample_period) return 0; if (ppmu->limited_pmc_event(ev)) return 1; /* * The requested event_id isn't on a limited PMC already; * see if any alternative code goes on a limited PMC. */ if (!ppmu->get_alternatives) return 0; flags |= PPMU_LIMITED_PMC_OK | PPMU_LIMITED_PMC_REQD; n = ppmu->get_alternatives(ev, flags, alt); return n > 0; } /* * Find an alternative event_id that goes on a normal PMC, if possible, * and return the event_id code, or 0 if there is no such alternative. * (Note: event_id code 0 is "don't count" on all machines.) */ static u64 normal_pmc_alternative(u64 ev, unsigned long flags) { u64 alt[MAX_EVENT_ALTERNATIVES]; int n; flags &= ~(PPMU_LIMITED_PMC_OK | PPMU_LIMITED_PMC_REQD); n = ppmu->get_alternatives(ev, flags, alt); if (!n) return 0; return alt[0]; } /* Number of perf_events counting hardware events */ static atomic_t num_events; /* Used to avoid races in calling reserve/release_pmc_hardware */ static DEFINE_MUTEX(pmc_reserve_mutex); /* * Release the PMU if this is the last perf_event. */ static void hw_perf_event_destroy(struct perf_event *event) { if (!atomic_add_unless(&num_events, -1, 1)) { mutex_lock(&pmc_reserve_mutex); if (atomic_dec_return(&num_events) == 0) release_pmc_hardware(); mutex_unlock(&pmc_reserve_mutex); } } /* * Translate a generic cache event_id config to a raw event_id code. */ static int hw_perf_cache_event(u64 config, u64 *eventp) { unsigned long type, op, result; int ev; if (!ppmu->cache_events) return -EINVAL; /* unpack config */ type = config & 0xff; op = (config >> 8) & 0xff; result = (config >> 16) & 0xff; if (type >= PERF_COUNT_HW_CACHE_MAX || op >= PERF_COUNT_HW_CACHE_OP_MAX || result >= PERF_COUNT_HW_CACHE_RESULT_MAX) return -EINVAL; ev = (*ppmu->cache_events)[type][op][result]; if (ev == 0) return -EOPNOTSUPP; if (ev == -1) return -EINVAL; *eventp = ev; return 0; } static int power_pmu_event_init(struct perf_event *event) { u64 ev; unsigned long flags; struct perf_event *ctrs[MAX_HWEVENTS]; u64 events[MAX_HWEVENTS]; unsigned int cflags[MAX_HWEVENTS]; int n; int err; struct cpu_hw_events *cpuhw; if (!ppmu) return -ENOENT; /* does not support taken branch sampling */ if (has_branch_stack(event)) return -EOPNOTSUPP; switch (event->attr.type) { case PERF_TYPE_HARDWARE: ev = event->attr.config; if (ev >= ppmu->n_generic || ppmu->generic_events[ev] == 0) return -EOPNOTSUPP; ev = ppmu->generic_events[ev]; break; case PERF_TYPE_HW_CACHE: err = hw_perf_cache_event(event->attr.config, &ev); if (err) return err; break; case PERF_TYPE_RAW: ev = event->attr.config; break; default: return -ENOENT; } event->hw.config_base = ev; event->hw.idx = 0; /* * If we are not running on a hypervisor, force the * exclude_hv bit to 0 so that we don't care what * the user set it to. */ if (!firmware_has_feature(FW_FEATURE_LPAR)) event->attr.exclude_hv = 0; /* * If this is a per-task event, then we can use * PM_RUN_* events interchangeably with their non RUN_* * equivalents, e.g. PM_RUN_CYC instead of PM_CYC. * XXX we should check if the task is an idle task. */ flags = 0; if (event->attach_state & PERF_ATTACH_TASK) flags |= PPMU_ONLY_COUNT_RUN; /* * If this machine has limited events, check whether this * event_id could go on a limited event. */ if (ppmu->flags & PPMU_LIMITED_PMC5_6) { if (can_go_on_limited_pmc(event, ev, flags)) { flags |= PPMU_LIMITED_PMC_OK; } else if (ppmu->limited_pmc_event(ev)) { /* * The requested event_id is on a limited PMC, * but we can't use a limited PMC; see if any * alternative goes on a normal PMC. */ ev = normal_pmc_alternative(ev, flags); if (!ev) return -EINVAL; } } /* * If this is in a group, check if it can go on with all the * other hardware events in the group. We assume the event * hasn't been linked into its leader's sibling list at this point. */ n = 0; if (event->group_leader != event) { n = collect_events(event->group_leader, ppmu->n_counter - 1, ctrs, events, cflags); if (n < 0) return -EINVAL; } events[n] = ev; ctrs[n] = event; cflags[n] = flags; if (check_excludes(ctrs, cflags, n, 1)) return -EINVAL; cpuhw = &get_cpu_var(cpu_hw_events); err = power_check_constraints(cpuhw, events, cflags, n + 1); put_cpu_var(cpu_hw_events); if (err) return -EINVAL; event->hw.config = events[n]; event->hw.event_base = cflags[n]; event->hw.last_period = event->hw.sample_period; local64_set(&event->hw.period_left, event->hw.last_period); /* * See if we need to reserve the PMU. * If no events are currently in use, then we have to take a * mutex to ensure that we don't race with another task doing * reserve_pmc_hardware or release_pmc_hardware. */ err = 0; if (!atomic_inc_not_zero(&num_events)) { mutex_lock(&pmc_reserve_mutex); if (atomic_read(&num_events) == 0 && reserve_pmc_hardware(perf_event_interrupt)) err = -EBUSY; else atomic_inc(&num_events); mutex_unlock(&pmc_reserve_mutex); } event->destroy = hw_perf_event_destroy; return err; } static int power_pmu_event_idx(struct perf_event *event) { return event->hw.idx; } ssize_t power_events_sysfs_show(struct device *dev, struct device_attribute *attr, char *page) { struct perf_pmu_events_attr *pmu_attr; pmu_attr = container_of(attr, struct perf_pmu_events_attr, attr); return sprintf(page, "event=0x%02llx\n", pmu_attr->id); } struct pmu power_pmu = { .pmu_enable = power_pmu_enable, .pmu_disable = power_pmu_disable, .event_init = power_pmu_event_init, .add = power_pmu_add, .del = power_pmu_del, .start = power_pmu_start, .stop = power_pmu_stop, .read = power_pmu_read, .start_txn = power_pmu_start_txn, .cancel_txn = power_pmu_cancel_txn, .commit_txn = power_pmu_commit_txn, .event_idx = power_pmu_event_idx, }; /* * A counter has overflowed; update its count and record * things if requested. Note that interrupts are hard-disabled * here so there is no possibility of being interrupted. */ static void record_and_restart(struct perf_event *event, unsigned long val, struct pt_regs *regs) { u64 period = event->hw.sample_period; s64 prev, delta, left; int record = 0; if (event->hw.state & PERF_HES_STOPPED) { write_pmc(event->hw.idx, 0); return; } /* we don't have to worry about interrupts here */ prev = local64_read(&event->hw.prev_count); delta = check_and_compute_delta(prev, val); local64_add(delta, &event->count); /* * See if the total period for this event has expired, * and update for the next period. */ val = 0; left = local64_read(&event->hw.period_left) - delta; if (delta == 0) left++; if (period) { if (left <= 0) { left += period; if (left <= 0) left = period; record = siar_valid(regs); event->hw.last_period = event->hw.sample_period; } if (left < 0x80000000LL) val = 0x80000000LL - left; } write_pmc(event->hw.idx, val); local64_set(&event->hw.prev_count, val); local64_set(&event->hw.period_left, left); perf_event_update_userpage(event); /* * Finally record data if requested. */ if (record) { struct perf_sample_data data; perf_sample_data_init(&data, ~0ULL, event->hw.last_period); if (event->attr.sample_type & PERF_SAMPLE_ADDR) perf_get_data_addr(regs, &data.addr); if (perf_event_overflow(event, &data, regs)) power_pmu_stop(event, 0); } } /* * Called from generic code to get the misc flags (i.e. processor mode) * for an event_id. */ unsigned long perf_misc_flags(struct pt_regs *regs) { u32 flags = perf_get_misc_flags(regs); if (flags) return flags; return user_mode(regs) ? PERF_RECORD_MISC_USER : PERF_RECORD_MISC_KERNEL; } /* * Called from generic code to get the instruction pointer * for an event_id. */ unsigned long perf_instruction_pointer(struct pt_regs *regs) { bool use_siar = regs_use_siar(regs); if (use_siar && siar_valid(regs)) return mfspr(SPRN_SIAR) + perf_ip_adjust(regs); else if (use_siar) return 0; // no valid instruction pointer else return regs->nip; } static bool pmc_overflow_power7(unsigned long val) { /* * Events on POWER7 can roll back if a speculative event doesn't * eventually complete. Unfortunately in some rare cases they will * raise a performance monitor exception. We need to catch this to * ensure we reset the PMC. In all cases the PMC will be 256 or less * cycles from overflow. * * We only do this if the first pass fails to find any overflowing * PMCs because a user might set a period of less than 256 and we * don't want to mistakenly reset them. */ if ((0x80000000 - val) <= 256) return true; return false; } static bool pmc_overflow(unsigned long val) { if ((int)val < 0) return true; return false; } /* * Performance monitor interrupt stuff */ static void perf_event_interrupt(struct pt_regs *regs) { int i, j; struct cpu_hw_events *cpuhw = &__get_cpu_var(cpu_hw_events); struct perf_event *event; unsigned long val[8]; int found, active; int nmi; if (cpuhw->n_limited) freeze_limited_counters(cpuhw, mfspr(SPRN_PMC5), mfspr(SPRN_PMC6)); perf_read_regs(regs); nmi = perf_intr_is_nmi(regs); if (nmi) nmi_enter(); else irq_enter(); /* Read all the PMCs since we'll need them a bunch of times */ for (i = 0; i < ppmu->n_counter; ++i) val[i] = read_pmc(i + 1); /* Try to find what caused the IRQ */ found = 0; for (i = 0; i < ppmu->n_counter; ++i) { if (!pmc_overflow(val[i])) continue; if (is_limited_pmc(i + 1)) continue; /* these won't generate IRQs */ /* * We've found one that's overflowed. For active * counters we need to log this. For inactive * counters, we need to reset it anyway */ found = 1; active = 0; for (j = 0; j < cpuhw->n_events; ++j) { event = cpuhw->event[j]; if (event->hw.idx == (i + 1)) { active = 1; record_and_restart(event, val[i], regs); break; } } if (!active) /* reset non active counters that have overflowed */ write_pmc(i + 1, 0); } if (!found && pvr_version_is(PVR_POWER7)) { /* check active counters for special buggy p7 overflow */ for (i = 0; i < cpuhw->n_events; ++i) { event = cpuhw->event[i]; if (!event->hw.idx || is_limited_pmc(event->hw.idx)) continue; if (pmc_overflow_power7(val[event->hw.idx - 1])) { /* event has overflowed in a buggy way*/ found = 1; record_and_restart(event, val[event->hw.idx - 1], regs); } } } if ((!found) && printk_ratelimit()) printk(KERN_WARNING "Can't find PMC that caused IRQ\n"); /* * Reset MMCR0 to its normal value. This will set PMXE and * clear FC (freeze counters) and PMAO (perf mon alert occurred) * and thus allow interrupts to occur again. * XXX might want to use MSR.PM to keep the events frozen until * we get back out of this interrupt. */ write_mmcr0(cpuhw, cpuhw->mmcr[0]); if (nmi) nmi_exit(); else irq_exit(); } static void power_pmu_setup(int cpu) { struct cpu_hw_events *cpuhw = &per_cpu(cpu_hw_events, cpu); if (!ppmu) return; memset(cpuhw, 0, sizeof(*cpuhw)); cpuhw->mmcr[0] = MMCR0_FC; } static int __cpuinit power_pmu_notifier(struct notifier_block *self, unsigned long action, void *hcpu) { unsigned int cpu = (long)hcpu; switch (action & ~CPU_TASKS_FROZEN) { case CPU_UP_PREPARE: power_pmu_setup(cpu); break; default: break; } return NOTIFY_OK; } int __cpuinit register_power_pmu(struct power_pmu *pmu) { if (ppmu) return -EBUSY; /* something's already registered */ ppmu = pmu; pr_info("%s performance monitor hardware support registered\n", pmu->name); power_pmu.attr_groups = ppmu->attr_groups; #ifdef MSR_HV /* * Use FCHV to ignore kernel events if MSR.HV is set. */ if (mfmsr() & MSR_HV) freeze_events_kernel = MMCR0_FCHV; #endif /* CONFIG_PPC64 */ perf_pmu_register(&power_pmu, "cpu", PERF_TYPE_RAW); perf_cpu_notifier(power_pmu_notifier); return 0; }