diff options
Diffstat (limited to 'arch/powerpc/kernel/perf_event.c')
| -rw-r--r-- | arch/powerpc/kernel/perf_event.c | 1315 |
1 files changed, 1315 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/perf_event.c b/arch/powerpc/kernel/perf_event.c new file mode 100644 index 00000000000..c98321fcb45 --- /dev/null +++ b/arch/powerpc/kernel/perf_event.c @@ -0,0 +1,1315 @@ +/* + * 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 <linux/kernel.h> +#include <linux/sched.h> +#include <linux/perf_event.h> +#include <linux/percpu.h> +#include <linux/hardirq.h> +#include <asm/reg.h> +#include <asm/pmc.h> +#include <asm/machdep.h> +#include <asm/firmware.h> +#include <asm/ptrace.h> + +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_event[MAX_LIMITED_HWEVENTS]; + u8 limited_hwidx[MAX_LIMITED_HWEVENTS]; + u64 alternatives[MAX_HWEVENTS][MAX_EVENT_ALTERNATIVES]; + unsigned long amasks[MAX_HWEVENTS][MAX_EVENT_ALTERNATIVES]; + unsigned long avalues[MAX_HWEVENTS][MAX_EVENT_ALTERNATIVES]; +}; +DEFINE_PER_CPU(struct cpu_hw_events, cpu_hw_events); + +struct power_pmu *ppmu; + +/* + * Normally, to ignore kernel events we set the FCS (freeze events + * 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) { } +static inline int perf_intr_is_nmi(struct pt_regs *regs) +{ + return 0; +} + +#endif /* CONFIG_PPC32 */ + +/* + * 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 ((mmcra & MMCRA_SAMPLE_ENABLE) && !(ppmu->flags & PPMU_ALT_SIPR)) { + 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 + * bit in MMCRA. + */ +static inline void perf_get_data_addr(struct pt_regs *regs, u64 *addrp) +{ + unsigned long mmcra = regs->dsisr; + unsigned long sdsync = (ppmu->flags & PPMU_ALT_SIPR) ? + POWER6_MMCRA_SDSYNC : MMCRA_SDSYNC; + + if (!(mmcra & MMCRA_SAMPLE_ENABLE) || (mmcra & sdsync)) + *addrp = mfspr(SPRN_SDAR); +} + +static inline u32 perf_get_misc_flags(struct pt_regs *regs) +{ + unsigned long mmcra = regs->dsisr; + + if (TRAP(regs) != 0xf00) + return 0; /* not a PMU interrupt */ + + if (ppmu->flags & PPMU_ALT_SIPR) { + if (mmcra & POWER6_MMCRA_SIHV) + return PERF_RECORD_MISC_HYPERVISOR; + return (mmcra & POWER6_MMCRA_SIPR) ? + PERF_RECORD_MISC_USER : PERF_RECORD_MISC_KERNEL; + } + if (mmcra & MMCRA_SIHV) + return PERF_RECORD_MISC_HYPERVISOR; + return (mmcra & MMCRA_SIPR) ? PERF_RECORD_MISC_USER : + PERF_RECORD_MISC_KERNEL; +} + +/* + * Overload regs->dsisr to store MMCRA so we only need to read it once + * on each interrupt. + */ +static inline void perf_read_regs(struct pt_regs *regs) +{ + regs->dsisr = mfspr(SPRN_MMCRA); +} + +/* + * 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; +} + +#endif /* CONFIG_PPC64 */ + +static void perf_event_interrupt(struct pt_regs *regs); + +void perf_event_print_debug(void) +{ +} + +/* + * Read one performance monitor event (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_event) + 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 void power_pmu_read(struct perf_event *event) +{ + s64 val, delta, prev; + + 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 = atomic64_read(&event->hw.prev_count); + barrier(); + val = read_pmc(event->hw.idx); + } while (atomic64_cmpxchg(&event->hw.prev_count, prev, val) != prev); + + /* The events are only 32 bits wide */ + delta = (val - prev) & 0xfffffffful; + atomic64_add(delta, &event->count); + atomic64_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_events(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_event[i]; + if (!event->hw.idx) + continue; + val = (event->hw.idx == 5) ? pmc5 : pmc6; + prev = atomic64_read(&event->hw.prev_count); + event->hw.idx = 0; + delta = (val - prev) & 0xfffffffful; + atomic64_add(delta, &event->count); + } +} + +static void thaw_limited_events(struct cpu_hw_events *cpuhw, + unsigned long pmc5, unsigned long pmc6) +{ + struct perf_event *event; + u64 val; + int i; + + for (i = 0; i < cpuhw->n_limited; ++i) { + event = cpuhw->limited_event[i]; + event->hw.idx = cpuhw->limited_hwidx[i]; + val = (event->hw.idx == 5) ? pmc5 : pmc6; + atomic64_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_events(cpuhw, pmc5, pmc6); + else + thaw_limited_events(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. + */ +void hw_perf_disable(void) +{ + 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 events' 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. + */ +void hw_perf_enable(void) +{ + 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_event[n_lim] = event; + cpuhw->limited_hwidx[n_lim] = idx; + ++n_lim; + continue; + } + val = 0; + if (event->hw.sample_period) { + left = atomic64_read(&event->hw.period_left); + if (left < 0x80000000L) + val = 0x80000000L - left; + } + atomic64_set(&event->hw.prev_count, val); + event->hw.idx = idx; + 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, list_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; +} + +static void event_sched_in(struct perf_event *event, int cpu) +{ + event->state = PERF_EVENT_STATE_ACTIVE; + event->oncpu = cpu; + event->tstamp_running += event->ctx->time - event->tstamp_stopped; + if (is_software_event(event)) + event->pmu->enable(event); +} + +/* + * Called to enable a whole group of events. + * Returns 1 if the group was enabled, or -EAGAIN if it could not be. + * Assumes the caller has disabled interrupts and has + * frozen the PMU with hw_perf_save_disable. + */ +int hw_perf_group_sched_in(struct perf_event *group_leader, + struct perf_cpu_context *cpuctx, + struct perf_event_context *ctx, int cpu) +{ + struct cpu_hw_events *cpuhw; + long i, n, n0; + struct perf_event *sub; + + if (!ppmu) + return 0; + cpuhw = &__get_cpu_var(cpu_hw_events); + n0 = cpuhw->n_events; + n = collect_events(group_leader, ppmu->n_event - n0, + &cpuhw->event[n0], &cpuhw->events[n0], + &cpuhw->flags[n0]); + if (n < 0) + return -EAGAIN; + if (check_excludes(cpuhw->event, cpuhw->flags, n0, n)) + return -EAGAIN; + i = power_check_constraints(cpuhw, cpuhw->events, cpuhw->flags, n + n0); + if (i < 0) + return -EAGAIN; + cpuhw->n_events = n0 + n; + cpuhw->n_added += n; + + /* + * OK, this group can go on; update event states etc., + * and enable any software events + */ + for (i = n0; i < n0 + n; ++i) + cpuhw->event[i]->hw.config = cpuhw->events[i]; + cpuctx->active_oncpu += n; + n = 1; + event_sched_in(group_leader, cpu); + list_for_each_entry(sub, &group_leader->sibling_list, list_entry) { + if (sub->state != PERF_EVENT_STATE_OFF) { + event_sched_in(sub, cpu); + ++n; + } + } + ctx->nr_active += n; + + return 1; +} + +/* + * 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_enable(struct perf_event *event) +{ + struct cpu_hw_events *cpuhw; + unsigned long flags; + int n0; + int ret = -EAGAIN; + + local_irq_save(flags); + perf_disable(); + + /* + * 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_event) + goto out; + cpuhw->event[n0] = event; + cpuhw->events[n0] = event->hw.config; + cpuhw->flags[n0] = event->hw.event_base; + 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]; + ++cpuhw->n_events; + ++cpuhw->n_added; + + ret = 0; + out: + perf_enable(); + local_irq_restore(flags); + return ret; +} + +/* + * Remove a event from the PMU. + */ +static void power_pmu_disable(struct perf_event *event) +{ + struct cpu_hw_events *cpuhw; + long i; + unsigned long flags; + + local_irq_save(flags); + perf_disable(); + + 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->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_event[i]) + break; + if (i < cpuhw->n_limited) { + while (++i < cpuhw->n_limited) { + cpuhw->limited_event[i-1] = cpuhw->limited_event[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_enable(); + local_irq_restore(flags); +} + +/* + * Re-enable interrupts on a event after they were throttled + * because they were coming too fast. + */ +static void power_pmu_unthrottle(struct perf_event *event) +{ + s64 val, left; + unsigned long flags; + + if (!event->hw.idx || !event->hw.sample_period) + return; + local_irq_save(flags); + perf_disable(); + power_pmu_read(event); + left = event->hw.sample_period; + event->hw.last_period = left; + val = 0; + if (left < 0x80000000L) + val = 0x80000000L - left; + write_pmc(event->hw.idx, val); + atomic64_set(&event->hw.prev_count, val); + atomic64_set(&event->hw.period_left, left); + perf_event_update_userpage(event); + perf_enable(); + local_irq_restore(flags); +} + +struct pmu power_pmu = { + .enable = power_pmu_enable, + .disable = power_pmu_disable, + .read = power_pmu_read, + .unthrottle = power_pmu_unthrottle, +}; + +/* + * 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; +} + +const struct pmu *hw_perf_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 ERR_PTR(-ENXIO); + switch (event->attr.type) { + case PERF_TYPE_HARDWARE: + ev = event->attr.config; + if (ev >= ppmu->n_generic || ppmu->generic_events[ev] == 0) + return ERR_PTR(-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_PTR(err); + break; + case PERF_TYPE_RAW: + ev = event->attr.config; + break; + default: + return ERR_PTR(-EINVAL); + } + 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->ctx->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 ERR_PTR(-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_event - 1, + ctrs, events, cflags); + if (n < 0) + return ERR_PTR(-EINVAL); + } + events[n] = ev; + ctrs[n] = event; + cflags[n] = flags; + if (check_excludes(ctrs, cflags, n, 1)) + return ERR_PTR(-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 ERR_PTR(-EINVAL); + + event->hw.config = events[n]; + event->hw.event_base = cflags[n]; + event->hw.last_period = event->hw.sample_period; + atomic64_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; + + if (err) + return ERR_PTR(err); + return &power_pmu; +} + +/* + * A event 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, int nmi) +{ + u64 period = event->hw.sample_period; + s64 prev, delta, left; + int record = 0; + + /* we don't have to worry about interrupts here */ + prev = atomic64_read(&event->hw.prev_count); + delta = (val - prev) & 0xfffffffful; + atomic64_add(delta, &event->count); + + /* + * See if the total period for this event has expired, + * and update for the next period. + */ + val = 0; + left = atomic64_read(&event->hw.period_left) - delta; + if (period) { + if (left <= 0) { + left += period; + if (left <= 0) + left = period; + record = 1; + } + if (left < 0x80000000LL) + val = 0x80000000LL - left; + } + + /* + * Finally record data if requested. + */ + if (record) { + struct perf_sample_data data = { + .addr = 0, + .period = event->hw.last_period, + }; + + if (event->attr.sample_type & PERF_SAMPLE_ADDR) + perf_get_data_addr(regs, &data.addr); + + if (perf_event_overflow(event, nmi, &data, regs)) { + /* + * Interrupts are coming too fast - throttle them + * by setting the event to 0, so it will be + * at least 2^30 cycles until the next interrupt + * (assuming each event counts at most 2 counts + * per cycle). + */ + val = 0; + left = ~0ULL >> 1; + } + } + + write_pmc(event->hw.idx, val); + atomic64_set(&event->hw.prev_count, val); + atomic64_set(&event->hw.period_left, left); + perf_event_update_userpage(event); +} + +/* + * 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) +{ + unsigned long ip; + + if (TRAP(regs) != 0xf00) + return regs->nip; /* not a PMU interrupt */ + + ip = mfspr(SPRN_SIAR) + perf_ip_adjust(regs); + return ip; +} + +/* + * Performance monitor interrupt stuff + */ +static void perf_event_interrupt(struct pt_regs *regs) +{ + int i; + struct cpu_hw_events *cpuhw = &__get_cpu_var(cpu_hw_events); + struct perf_event *event; + unsigned long val; + int found = 0; + int nmi; + + if (cpuhw->n_limited) + freeze_limited_events(cpuhw, mfspr(SPRN_PMC5), + mfspr(SPRN_PMC6)); + + perf_read_regs(regs); + + nmi = perf_intr_is_nmi(regs); + if (nmi) + nmi_enter(); + else + irq_enter(); + + for (i = 0; i < cpuhw->n_events; ++i) { + event = cpuhw->event[i]; + if (!event->hw.idx || is_limited_pmc(event->hw.idx)) + continue; + val = read_pmc(event->hw.idx); + if ((int)val < 0) { + /* event has overflowed */ + found = 1; + record_and_restart(event, val, regs, nmi); + } + } + + /* + * In case we didn't find and reset the event that caused + * the interrupt, scan all events and reset any that are + * negative, to avoid getting continual interrupts. + * Any that we processed in the previous loop will not be negative. + */ + if (!found) { + for (i = 0; i < ppmu->n_event; ++i) { + if (is_limited_pmc(i + 1)) + continue; + val = read_pmc(i + 1); + if ((int)val < 0) + write_pmc(i + 1, 0); + } + } + + /* + * Reset MMCR0 to its normal value. This will set PMXE and + * clear FC (freeze events) 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(); +} + +void hw_perf_event_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; +} + +int 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); + +#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 */ + + return 0; +} |