diff options
Diffstat (limited to 'kernel/events')
| -rw-r--r-- | kernel/events/Makefile | 1 | ||||
| -rw-r--r-- | kernel/events/core.c | 88 | ||||
| -rw-r--r-- | kernel/events/hw_breakpoint.c | 648 | ||||
| -rw-r--r-- | kernel/events/hw_breakpoint_test.c | 333 |
4 files changed, 885 insertions, 185 deletions
diff --git a/kernel/events/Makefile b/kernel/events/Makefile index 8591c180b52b..91a62f566743 100644 --- a/kernel/events/Makefile +++ b/kernel/events/Makefile @@ -2,4 +2,5 @@ obj-y := core.o ring_buffer.o callchain.o obj-$(CONFIG_HAVE_HW_BREAKPOINT) += hw_breakpoint.o +obj-$(CONFIG_HW_BREAKPOINT_KUNIT_TEST) += hw_breakpoint_test.o obj-$(CONFIG_UPROBES) += uprobes.o diff --git a/kernel/events/core.c b/kernel/events/core.c index ff4bffc502c6..43b0df997d13 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -1468,6 +1468,8 @@ static void __update_context_time(struct perf_event_context *ctx, bool adv) { u64 now = perf_clock(); + lockdep_assert_held(&ctx->lock); + if (adv) ctx->time += now - ctx->timestamp; ctx->timestamp = now; @@ -2224,16 +2226,22 @@ static inline int __pmu_filter_match(struct perf_event *event) static inline int pmu_filter_match(struct perf_event *event) { struct perf_event *sibling; + unsigned long flags; + int ret = 1; if (!__pmu_filter_match(event)) return 0; + local_irq_save(flags); for_each_sibling_event(sibling, event) { - if (!__pmu_filter_match(sibling)) - return 0; + if (!__pmu_filter_match(sibling)) { + ret = 0; + break; + } } + local_irq_restore(flags); - return 1; + return ret; } static inline int @@ -6794,11 +6802,10 @@ out_put: static void __perf_event_header__init_id(struct perf_event_header *header, struct perf_sample_data *data, - struct perf_event *event) + struct perf_event *event, + u64 sample_type) { - u64 sample_type = event->attr.sample_type; - - data->type = sample_type; + data->type = event->attr.sample_type; header->size += event->id_header_size; if (sample_type & PERF_SAMPLE_TID) { @@ -6827,7 +6834,7 @@ void perf_event_header__init_id(struct perf_event_header *header, struct perf_event *event) { if (event->attr.sample_id_all) - __perf_event_header__init_id(header, data, event); + __perf_event_header__init_id(header, data, event, event->attr.sample_type); } static void __perf_event__output_id_sample(struct perf_output_handle *handle, @@ -6976,11 +6983,6 @@ static void perf_output_read(struct perf_output_handle *handle, perf_output_read_one(handle, event, enabled, running); } -static inline bool perf_sample_save_hw_index(struct perf_event *event) -{ - return event->attr.branch_sample_type & PERF_SAMPLE_BRANCH_HW_INDEX; -} - void perf_output_sample(struct perf_output_handle *handle, struct perf_event_header *header, struct perf_sample_data *data, @@ -7062,14 +7064,14 @@ void perf_output_sample(struct perf_output_handle *handle, } if (sample_type & PERF_SAMPLE_BRANCH_STACK) { - if (data->br_stack) { + if (data->sample_flags & PERF_SAMPLE_BRANCH_STACK) { size_t size; size = data->br_stack->nr * sizeof(struct perf_branch_entry); perf_output_put(handle, data->br_stack->nr); - if (perf_sample_save_hw_index(event)) + if (branch_sample_hw_index(event)) perf_output_put(handle, data->br_stack->hw_idx); perf_output_copy(handle, data->br_stack->entries, size); } else { @@ -7312,6 +7314,7 @@ void perf_prepare_sample(struct perf_event_header *header, struct pt_regs *regs) { u64 sample_type = event->attr.sample_type; + u64 filtered_sample_type; header->type = PERF_RECORD_SAMPLE; header->size = sizeof(*header) + event->header_size; @@ -7319,7 +7322,12 @@ void perf_prepare_sample(struct perf_event_header *header, header->misc = 0; header->misc |= perf_misc_flags(regs); - __perf_event_header__init_id(header, data, event); + /* + * Clear the sample flags that have already been done by the + * PMU driver. + */ + filtered_sample_type = sample_type & ~data->sample_flags; + __perf_event_header__init_id(header, data, event, filtered_sample_type); if (sample_type & (PERF_SAMPLE_IP | PERF_SAMPLE_CODE_PAGE_SIZE)) data->ip = perf_instruction_pointer(regs); @@ -7327,7 +7335,7 @@ void perf_prepare_sample(struct perf_event_header *header, if (sample_type & PERF_SAMPLE_CALLCHAIN) { int size = 1; - if (!(sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY)) + if (filtered_sample_type & PERF_SAMPLE_CALLCHAIN) data->callchain = perf_callchain(event, regs); size += data->callchain->nr; @@ -7339,7 +7347,7 @@ void perf_prepare_sample(struct perf_event_header *header, struct perf_raw_record *raw = data->raw; int size; - if (raw) { + if (raw && (data->sample_flags & PERF_SAMPLE_RAW)) { struct perf_raw_frag *frag = &raw->frag; u32 sum = 0; @@ -7355,6 +7363,7 @@ void perf_prepare_sample(struct perf_event_header *header, frag->pad = raw->size - sum; } else { size = sizeof(u64); + data->raw = NULL; } header->size += size; @@ -7362,8 +7371,8 @@ void perf_prepare_sample(struct perf_event_header *header, if (sample_type & PERF_SAMPLE_BRANCH_STACK) { int size = sizeof(u64); /* nr */ - if (data->br_stack) { - if (perf_sample_save_hw_index(event)) + if (data->sample_flags & PERF_SAMPLE_BRANCH_STACK) { + if (branch_sample_hw_index(event)) size += sizeof(u64); size += data->br_stack->nr @@ -7412,6 +7421,20 @@ void perf_prepare_sample(struct perf_event_header *header, header->size += size; } + if (filtered_sample_type & PERF_SAMPLE_WEIGHT_TYPE) + data->weight.full = 0; + + if (filtered_sample_type & PERF_SAMPLE_DATA_SRC) + data->data_src.val = PERF_MEM_NA; + + if (filtered_sample_type & PERF_SAMPLE_TRANSACTION) + data->txn = 0; + + if (sample_type & (PERF_SAMPLE_ADDR | PERF_SAMPLE_PHYS_ADDR | PERF_SAMPLE_DATA_PAGE_SIZE)) { + if (filtered_sample_type & PERF_SAMPLE_ADDR) + data->addr = 0; + } + if (sample_type & PERF_SAMPLE_REGS_INTR) { /* regs dump ABI info */ int size = sizeof(u64); @@ -7427,7 +7450,8 @@ void perf_prepare_sample(struct perf_event_header *header, header->size += size; } - if (sample_type & PERF_SAMPLE_PHYS_ADDR) + if (sample_type & PERF_SAMPLE_PHYS_ADDR && + filtered_sample_type & PERF_SAMPLE_PHYS_ADDR) data->phys_addr = perf_virt_to_phys(data->addr); #ifdef CONFIG_CGROUP_PERF @@ -9998,8 +10022,16 @@ static void bpf_overflow_handler(struct perf_event *event, goto out; rcu_read_lock(); prog = READ_ONCE(event->prog); - if (prog) + if (prog) { + if (prog->call_get_stack && + (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) && + !(data->sample_flags & PERF_SAMPLE_CALLCHAIN)) { + data->callchain = perf_callchain(event, regs); + data->sample_flags |= PERF_SAMPLE_CALLCHAIN; + } + ret = bpf_prog_run(prog, &ctx); + } rcu_read_unlock(); out: __this_cpu_dec(bpf_prog_active); @@ -10025,7 +10057,7 @@ static int perf_event_set_bpf_handler(struct perf_event *event, if (event->attr.precise_ip && prog->call_get_stack && - (!(event->attr.sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY) || + (!(event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) || event->attr.exclude_callchain_kernel || event->attr.exclude_callchain_user)) { /* @@ -10942,7 +10974,7 @@ static ssize_t nr_addr_filters_show(struct device *dev, { struct pmu *pmu = dev_get_drvdata(dev); - return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters); + return scnprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters); } DEVICE_ATTR_RO(nr_addr_filters); @@ -10953,7 +10985,7 @@ type_show(struct device *dev, struct device_attribute *attr, char *page) { struct pmu *pmu = dev_get_drvdata(dev); - return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type); + return scnprintf(page, PAGE_SIZE - 1, "%d\n", pmu->type); } static DEVICE_ATTR_RO(type); @@ -10964,7 +10996,7 @@ perf_event_mux_interval_ms_show(struct device *dev, { struct pmu *pmu = dev_get_drvdata(dev); - return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms); + return scnprintf(page, PAGE_SIZE - 1, "%d\n", pmu->hrtimer_interval_ms); } static DEFINE_MUTEX(mux_interval_mutex); @@ -11718,11 +11750,9 @@ err_pmu: event->destroy(event); module_put(pmu->module); err_ns: - if (event->ns) - put_pid_ns(event->ns); if (event->hw.target) put_task_struct(event->hw.target); - kmem_cache_free(perf_event_cache, event); + call_rcu(&event->rcu_head, free_event_rcu); return ERR_PTR(err); } diff --git a/kernel/events/hw_breakpoint.c b/kernel/events/hw_breakpoint.c index f32320ac02fd..c3797701339c 100644 --- a/kernel/events/hw_breakpoint.c +++ b/kernel/events/hw_breakpoint.c @@ -17,61 +17,276 @@ * This file contains the arch-independent routines. */ +#include <linux/hw_breakpoint.h> + +#include <linux/atomic.h> +#include <linux/bug.h> +#include <linux/cpu.h> +#include <linux/export.h> +#include <linux/init.h> #include <linux/irqflags.h> -#include <linux/kallsyms.h> -#include <linux/notifier.h> -#include <linux/kprobes.h> #include <linux/kdebug.h> #include <linux/kernel.h> -#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/notifier.h> +#include <linux/percpu-rwsem.h> #include <linux/percpu.h> +#include <linux/rhashtable.h> #include <linux/sched.h> -#include <linux/init.h> #include <linux/slab.h> -#include <linux/list.h> -#include <linux/cpu.h> -#include <linux/smp.h> -#include <linux/bug.h> -#include <linux/hw_breakpoint.h> /* - * Constraints data + * Datastructure to track the total uses of N slots across tasks or CPUs; + * bp_slots_histogram::count[N] is the number of assigned N+1 breakpoint slots. + */ +struct bp_slots_histogram { +#ifdef hw_breakpoint_slots + atomic_t count[hw_breakpoint_slots(0)]; +#else + atomic_t *count; +#endif +}; + +/* + * Per-CPU constraints data. */ struct bp_cpuinfo { - /* Number of pinned cpu breakpoints in a cpu */ - unsigned int cpu_pinned; - /* tsk_pinned[n] is the number of tasks having n+1 breakpoints */ - unsigned int *tsk_pinned; - /* Number of non-pinned cpu/task breakpoints in a cpu */ - unsigned int flexible; /* XXX: placeholder, see fetch_this_slot() */ + /* Number of pinned CPU breakpoints in a CPU. */ + unsigned int cpu_pinned; + /* Histogram of pinned task breakpoints in a CPU. */ + struct bp_slots_histogram tsk_pinned; }; static DEFINE_PER_CPU(struct bp_cpuinfo, bp_cpuinfo[TYPE_MAX]); -static int nr_slots[TYPE_MAX]; static struct bp_cpuinfo *get_bp_info(int cpu, enum bp_type_idx type) { return per_cpu_ptr(bp_cpuinfo + type, cpu); } +/* Number of pinned CPU breakpoints globally. */ +static struct bp_slots_histogram cpu_pinned[TYPE_MAX]; +/* Number of pinned CPU-independent task breakpoints. */ +static struct bp_slots_histogram tsk_pinned_all[TYPE_MAX]; + /* Keep track of the breakpoints attached to tasks */ -static LIST_HEAD(bp_task_head); +static struct rhltable task_bps_ht; +static const struct rhashtable_params task_bps_ht_params = { + .head_offset = offsetof(struct hw_perf_event, bp_list), + .key_offset = offsetof(struct hw_perf_event, target), + .key_len = sizeof_field(struct hw_perf_event, target), + .automatic_shrinking = true, +}; -static int constraints_initialized; +static bool constraints_initialized __ro_after_init; -/* Gather the number of total pinned and un-pinned bp in a cpuset */ -struct bp_busy_slots { - unsigned int pinned; - unsigned int flexible; -}; +/* + * Synchronizes accesses to the per-CPU constraints; the locking rules are: + * + * 1. Atomic updates to bp_cpuinfo::tsk_pinned only require a held read-lock + * (due to bp_slots_histogram::count being atomic, no update are lost). + * + * 2. Holding a write-lock is required for computations that require a + * stable snapshot of all bp_cpuinfo::tsk_pinned. + * + * 3. In all other cases, non-atomic accesses require the appropriately held + * lock (read-lock for read-only accesses; write-lock for reads/writes). + */ +DEFINE_STATIC_PERCPU_RWSEM(bp_cpuinfo_sem); -/* Serialize accesses to the above constraints */ -static DEFINE_MUTEX(nr_bp_mutex); +/* + * Return mutex to serialize accesses to per-task lists in task_bps_ht. Since + * rhltable synchronizes concurrent insertions/deletions, independent tasks may + * insert/delete concurrently; therefore, a mutex per task is sufficient. + * + * Uses task_struct::perf_event_mutex, to avoid extending task_struct with a + * hw_breakpoint-only mutex, which may be infrequently used. The caveat here is + * that hw_breakpoint may contend with per-task perf event list management. The + * assumption is that perf usecases involving hw_breakpoints are very unlikely + * to result in unnecessary contention. + */ +static inline struct mutex *get_task_bps_mutex(struct perf_event *bp) +{ + struct task_struct *tsk = bp->hw.target; -__weak int hw_breakpoint_weight(struct perf_event *bp) + return tsk ? &tsk->perf_event_mutex : NULL; +} + +static struct mutex *bp_constraints_lock(struct perf_event *bp) +{ + struct mutex *tsk_mtx = get_task_bps_mutex(bp); + + if (tsk_mtx) { + /* + * Fully analogous to the perf_try_init_event() nesting + * argument in the comment near perf_event_ctx_lock_nested(); + * this child->perf_event_mutex cannot ever deadlock against + * the parent->perf_event_mutex usage from + * perf_event_task_{en,dis}able(). + * + * Specifically, inherited events will never occur on + * ->perf_event_list. + */ + mutex_lock_nested(tsk_mtx, SINGLE_DEPTH_NESTING); + percpu_down_read(&bp_cpuinfo_sem); + } else { + percpu_down_write(&bp_cpuinfo_sem); + } + + return tsk_mtx; +} + +static void bp_constraints_unlock(struct mutex *tsk_mtx) +{ + if (tsk_mtx) { + percpu_up_read(&bp_cpuinfo_sem); + mutex_unlock(tsk_mtx); + } else { + percpu_up_write(&bp_cpuinfo_sem); + } +} + +static bool bp_constraints_is_locked(struct perf_event *bp) +{ + struct mutex *tsk_mtx = get_task_bps_mutex(bp); + + return percpu_is_write_locked(&bp_cpuinfo_sem) || + (tsk_mtx ? mutex_is_locked(tsk_mtx) : + percpu_is_read_locked(&bp_cpuinfo_sem)); +} + +static inline void assert_bp_constraints_lock_held(struct perf_event *bp) +{ + struct mutex *tsk_mtx = get_task_bps_mutex(bp); + + if (tsk_mtx) + lockdep_assert_held(tsk_mtx); + lockdep_assert_held(&bp_cpuinfo_sem); +} + +#ifdef hw_breakpoint_slots +/* + * Number of breakpoint slots is constant, and the same for all types. + */ +static_assert(hw_breakpoint_slots(TYPE_INST) == hw_breakpoint_slots(TYPE_DATA)); +static inline int hw_breakpoint_slots_cached(int type) { return hw_breakpoint_slots(type); } +static inline int init_breakpoint_slots(void) { return 0; } +#else +/* + * Dynamic number of breakpoint slots. + */ +static int __nr_bp_slots[TYPE_MAX] __ro_after_init; + +static inline int hw_breakpoint_slots_cached(int type) +{ + return __nr_bp_slots[type]; +} + +static __init bool +bp_slots_histogram_alloc(struct bp_slots_histogram *hist, enum bp_type_idx type) +{ + hist->count = kcalloc(hw_breakpoint_slots_cached(type), sizeof(*hist->count), GFP_KERNEL); + return hist->count; +} + +static __init void bp_slots_histogram_free(struct bp_slots_histogram *hist) +{ + kfree(hist->count); +} + +static __init int init_breakpoint_slots(void) +{ + int i, cpu, err_cpu; + + for (i = 0; i < TYPE_MAX; i++) + __nr_bp_slots[i] = hw_breakpoint_slots(i); + + for_each_possible_cpu(cpu) { + for (i = 0; i < TYPE_MAX; i++) { + struct bp_cpuinfo *info = get_bp_info(cpu, i); + + if (!bp_slots_histogram_alloc(&info->tsk_pinned, i)) + goto err; + } + } + for (i = 0; i < TYPE_MAX; i++) { + if (!bp_slots_histogram_alloc(&cpu_pinned[i], i)) + goto err; + if (!bp_slots_histogram_alloc(&tsk_pinned_all[i], i)) + goto err; + } + + return 0; +err: + for_each_possible_cpu(err_cpu) { + for (i = 0; i < TYPE_MAX; i++) + bp_slots_histogram_free(&get_bp_info(err_cpu, i)->tsk_pinned); + if (err_cpu == cpu) + break; + } + for (i = 0; i < TYPE_MAX; i++) { + bp_slots_histogram_free(&cpu_pinned[i]); + bp_slots_histogram_free(&tsk_pinned_all[i]); + } + + return -ENOMEM; +} +#endif + +static inline void +bp_slots_histogram_add(struct bp_slots_histogram *hist, int old, int val) +{ + const int old_idx = old - 1; + const int new_idx = old_idx + val; + + if (old_idx >= 0) + WARN_ON(atomic_dec_return_relaxed(&hist->count[old_idx]) < 0); + if (new_idx >= 0) + WARN_ON(atomic_inc_return_relaxed(&hist->count[new_idx]) < 0); +} + +static int +bp_slots_histogram_max(struct bp_slots_histogram *hist, enum bp_type_idx type) +{ + for (int i = hw_breakpoint_slots_cached(type) - 1; i >= 0; i--) { + const int count = atomic_read(&hist->count[i]); + + /* Catch unexpected writers; we want a stable snapshot. */ + ASSERT_EXCLUSIVE_WRITER(hist->count[i]); + if (count > 0) + return i + 1; + WARN(count < 0, "inconsistent breakpoint slots histogram"); + } + + return 0; +} + +static int +bp_slots_histogram_max_merge(struct bp_slots_histogram *hist1, struct bp_slots_histogram *hist2, + enum bp_type_idx type) +{ + for (int i = hw_breakpoint_slots_cached(type) - 1; i >= 0; i--) { + const int count1 = atomic_read(&hist1->count[i]); + const int count2 = atomic_read(&hist2->count[i]); + + /* Catch unexpected writers; we want a stable snapshot. */ + ASSERT_EXCLUSIVE_WRITER(hist1->count[i]); + ASSERT_EXCLUSIVE_WRITER(hist2->count[i]); + if (count1 + count2 > 0) + return i + 1; + WARN(count1 < 0, "inconsistent breakpoint slots histogram"); + WARN(count2 < 0, "inconsistent breakpoint slots histogram"); + } + + return 0; +} + +#ifndef hw_breakpoint_weight +static inline int hw_breakpoint_weight(struct perf_event *bp) { return 1; } +#endif static inline enum bp_type_idx find_slot_idx(u64 bp_type) { @@ -82,39 +297,61 @@ static inline enum bp_type_idx find_slot_idx(u64 bp_type) } /* - * Report the maximum number of pinned breakpoints a task - * have in this cpu + * Return the maximum number of pinned breakpoints a task has in this CPU. */ static unsigned int max_task_bp_pinned(int cpu, enum bp_type_idx type) { - unsigned int *tsk_pinned = get_bp_info(cpu, type)->tsk_pinned; - int i; + struct bp_slots_histogram *tsk_pinned = &get_bp_info(cpu, type)->tsk_pinned; - for (i = nr_slots[type] - 1; i >= 0; i--) { - if (tsk_pinned[i] > 0) - return i + 1; - } - - return 0; + /* + * At this point we want to have acquired the bp_cpuinfo_sem as a + * writer to ensure that there are no concurrent writers in + * toggle_bp_task_slot() to tsk_pinned, and we get a stable snapshot. + */ + lockdep_assert_held_write(&bp_cpuinfo_sem); + return bp_slots_histogram_max_merge(tsk_pinned, &tsk_pinned_all[type], type); } /* * Count the number of breakpoints of the same type and same task. * The given event must be not on the list. + * + * If @cpu is -1, but the result of task_bp_pinned() is not CPU-independent, + * returns a negative value. */ static int task_bp_pinned(int cpu, struct perf_event *bp, enum bp_type_idx type) { - struct task_struct *tsk = bp->hw.target; + struct rhlist_head *head, *pos; struct perf_event *iter; int count = 0; - list_for_each_entry(iter, &bp_task_head, hw.bp_list) { - if (iter->hw.target == tsk && - find_slot_idx(iter->attr.bp_type) == type && - (iter->cpu < 0 || cpu == iter->cpu)) - count += hw_breakpoint_weight(iter); + /* + * We need a stable snapshot of the per-task breakpoint list. + */ + assert_bp_constraints_lock_held(bp); + + rcu_read_lock(); + head = rhltable_lookup(&task_bps_ht, &bp->hw.target, task_bps_ht_params); + if (!head) + goto out; + + rhl_for_each_entry_rcu(iter, pos, head, hw.bp_list) { + if (find_slot_idx(iter->attr.bp_type) != type) + continue; + + if (iter->cpu >= 0) { + if (cpu == -1) { + count = -1; + goto out; + } else if (cpu != iter->cpu) + continue; + } + + count += hw_breakpoint_weight(iter); } +out: + rcu_read_unlock(); return count; } @@ -126,16 +363,29 @@ static const struct cpumask *cpumask_of_bp(struct perf_event *bp) } /* - * Report the number of pinned/un-pinned breakpoints we have in - * a given cpu (cpu > -1) or in all of them (cpu = -1). + * Returns the max pinned breakpoint slots in a given + * CPU (cpu > -1) or across all of them (cpu = -1). */ -static void -fetch_bp_busy_slots(struct bp_busy_slots *slots, struct perf_event *bp, - enum bp_type_idx type) +static int +max_bp_pinned_slots(struct perf_event *bp, enum bp_type_idx type) { const struct cpumask *cpumask = cpumask_of_bp(bp); + int pinned_slots = 0; int cpu; + if (bp->hw.target && bp->cpu < 0) { + int max_pinned = task_bp_pinned(-1, bp, type); + + if (max_pinned >= 0) { + /* + * Fast path: task_bp_pinned() is CPU-independent and + * returns the same value for any CPU. + */ + max_pinned += bp_slots_histogram_max(&cpu_pinned[type], type); + return max_pinned; + } + } + for_each_cpu(cpu, cpumask) { struct bp_cpuinfo *info = get_bp_info(cpu, type); int nr; @@ -146,71 +396,131 @@ fetch_bp_busy_slots(struct bp_busy_slots *slots, struct perf_event *bp, else nr += task_bp_pinned(cpu, bp, type); - if (nr > slots->pinned) - slots->pinned = nr; - - nr = info->flexible; - if (nr > slots->flexible) - slots->flexible = nr; + pinned_slots = max(nr, pinned_slots); } -} -/* - * For now, continue to consider flexible as pinned, until we can - * ensure no flexible event can ever be scheduled before a pinned event - * in a same cpu. - */ -static void -fetch_this_slot(struct bp_busy_slots *slots, int weight) -{ - slots->pinned += weight; -} - -/* - * Add a pinned breakpoint for the given task in our constraint table - */ -static void toggle_bp_task_slot(struct perf_event *bp, int cpu, - enum bp_type_idx type, int weight) -{ - unsigned int *tsk_pinned = get_bp_info(cpu, type)->tsk_pinned; - int old_idx, new_idx; - - old_idx = task_bp_pinned(cpu, bp, type) - 1; - new_idx = old_idx + weight; - - if (old_idx >= 0) - tsk_pinned[old_idx]--; - if (new_idx >= 0) - tsk_pinned[new_idx]++; + return pinned_slots; } /* * Add/remove the given breakpoint in our constraint table */ -static void -toggle_bp_slot(struct perf_event *bp, bool enable, enum bp_type_idx type, - int weight) +static int +toggle_bp_slot(struct perf_event *bp, bool enable, enum bp_type_idx type, int weight) { - const struct cpumask *cpumask = cpumask_of_bp(bp); - int cpu; + int cpu, next_tsk_pinned; if (!enable) weight = -weight; - /* Pinned counter cpu profiling */ if (!bp->hw.target) { - get_bp_info(bp->cpu, type)->cpu_pinned += weight; - return; + /* + * Update the pinned CPU slots, in per-CPU bp_cpuinfo and in the + * global histogram. + */ + struct bp_cpuinfo *info = get_bp_info(bp->cpu, type); + + lockdep_assert_held_write(&bp_cpuinfo_sem); + bp_slots_histogram_add(&cpu_pinned[type], info->cpu_pinned, weight); + info->cpu_pinned += weight; + return 0; + } + + /* + * If bp->hw.target, tsk_pinned is only modified, but not used + * otherwise. We can permit concurrent updates as long as there are no + * other uses: having acquired bp_cpuinfo_sem as a reader allows + * concurrent updates here. Uses of tsk_pinned will require acquiring + * bp_cpuinfo_sem as a writer to stabilize tsk_pinned's value. + */ + lockdep_assert_held_read(&bp_cpuinfo_sem); + + /* + * Update the pinned task slots, in per-CPU bp_cpuinfo and in the global + * histogram. We need to take care of 4 cases: + * + * 1. This breakpoint targets all CPUs (cpu < 0), and there may only + * exist other task breakpoints targeting all CPUs. In this case we + * can simply update the global slots histogram. + * + * 2. This breakpoint targets a specific CPU (cpu >= 0), but there may + * only exist other task breakpoints targeting all CPUs. + * + * a. On enable: remove the existing breakpoints from the global + * slots histogram and use the per-CPU histogram. + * + * b. On disable: re-insert the existing breakpoints into the global + * slots histogram and remove from per-CPU histogram. + * + * 3. Some other existing task breakpoints target specific CPUs. Only + * update the per-CPU slots histogram. + */ + + if (!enable) { + /* + * Remove before updating histograms so we can determine if this + * was the last task breakpoint for a specific CPU. + */ + int ret = rhltable_remove(&task_bps_ht, &bp->hw.bp_list, task_bps_ht_params); + + if (ret) + return ret; + } + /* + * Note: If !enable, next_tsk_pinned will not count the to-be-removed breakpoint. + */ + next_tsk_pinned = task_bp_pinned(-1, bp, type); + + if (next_tsk_pinned >= 0) { + if (bp->cpu < 0) { /* Case 1: fast path */ + if (!enable) + next_tsk_pinned += hw_breakpoint_weight(bp); + bp_slots_histogram_add(&tsk_pinned_all[type], next_tsk_pinned, weight); + } else if (enable) { /* Case 2.a: slow path */ + /* Add existing to per-CPU histograms. */ + for_each_possible_cpu(cpu) { + bp_slots_histogram_add(&get_bp_info(cpu, type)->tsk_pinned, + 0, next_tsk_pinned); + } + /* Add this first CPU-pinned task breakpoint. */ + bp_slots_histogram_add(&get_bp_info(bp->cpu, type)->tsk_pinned, + next_tsk_pinned, weight); + /* Rebalance global task pinned histogram. */ + bp_slots_histogram_add(&tsk_pinned_all[type], next_tsk_pinned, + -next_tsk_pinned); + } else { /* Case 2.b: slow path */ + /* Remove this last CPU-pinned task breakpoint. */ + bp_slots_histogram_add(&get_bp_info(bp->cpu, type)->tsk_pinned, + next_tsk_pinned + hw_breakpoint_weight(bp), weight); + /* Remove all from per-CPU histograms. */ + for_each_possible_cpu(cpu) { + bp_slots_histogram_add(&get_bp_info(cpu, type)->tsk_pinned, + next_tsk_pinned, -next_tsk_pinned); + } + /* Rebalance global task pinned histogram. */ + bp_slots_histogram_add(&tsk_pinned_all[type], 0, next_tsk_pinned); + } + } else { /* Case 3: slow path */ + const struct cpumask *cpumask = cpumask_of_bp(bp); + + for_each_cpu(cpu, cpumask) { + next_tsk_pinned = task_bp_pinned(cpu, bp, type); + if (!enable) + next_tsk_pinned += hw_breakpoint_weight(bp); + bp_slots_histogram_add(&get_bp_info(cpu, type)->tsk_pinned, + next_tsk_pinned, weight); + } } - /* Pinned counter task profiling */ - for_each_cpu(cpu, cpumask) - toggle_bp_task_slot(bp, cpu, type, weight); + /* + * Readers want a stable snapshot of the per-task breakpoint list. + */ + assert_bp_constraints_lock_held(bp); if (enable) - list_add_tail(&bp->hw.bp_list, &bp_task_head); - else - list_del(&bp->hw.bp_list); + return rhltable_insert(&task_bps_ht, &bp->hw.bp_list, task_bps_ht_params); + + return 0; } __weak int arch_reserve_bp_slot(struct perf_event *bp) @@ -234,7 +544,12 @@ __weak void arch_unregister_hw_breakpoint(struct perf_event *bp) } /* - * Constraints to check before allowing this new breakpoint counter: + * Constraints to check before allowing this new breakpoint counter. + * + * Note: Flexible breakpoints are currently unimplemented, but outlined in the + * below algorithm for completeness. The implementation treats flexible as + * pinned due to no guarantee that we currently always schedule flexible events + * before a pinned event in a same CPU. * * == Non-pinned counter == (Considered as pinned for now) * @@ -276,8 +591,8 @@ __weak void arch_unregister_hw_breakpoint(struct perf_event *bp) */ static int __reserve_bp_slot(struct perf_event *bp, u64 bp_type) { - struct bp_busy_slots slots = {0}; enum bp_type_idx type; + int max_pinned_slots; int weight; int ret; @@ -293,36 +608,24 @@ static int __reserve_bp_slot(struct perf_event *bp, u64 bp_type) type = find_slot_idx(bp_type); weight = hw_breakpoint_weight(bp); - fetch_bp_busy_slots(&slots, bp, type); - /* - * Simulate the addition of this breakpoint to the constraints - * and see the result. - */ - fetch_this_slot(&slots, weight); - - /* Flexible counters need to keep at least one slot */ - if (slots.pinned + (!!slots.flexible) > nr_slots[type]) + /* Check if this new breakpoint can be satisfied across all CPUs. */ + max_pinned_slots = max_bp_pinned_slots(bp, type) + weight; + if (max_pinned_slots > hw_breakpoint_slots_cached(type)) return -ENOSPC; ret = arch_reserve_bp_slot(bp); if (ret) return ret; - toggle_bp_slot(bp, true, type, weight); - - return 0; + return toggle_bp_slot(bp, true, type, weight); } int reserve_bp_slot(struct perf_event *bp) { - int ret; - - mutex_lock(&nr_bp_mutex); - - ret = __reserve_bp_slot(bp, bp->attr.bp_type); - - mutex_unlock(&nr_bp_mutex); + struct mutex *mtx = bp_constraints_lock(bp); + int ret = __reserve_bp_slot(bp, bp->attr.bp_type); + bp_constraints_unlock(mtx); return ret; } @@ -335,17 +638,16 @@ static void __release_bp_slot(struct perf_event *bp, u64 bp_type) type = find_slot_idx(bp_type); weight = hw_breakpoint_weight(bp); - toggle_bp_slot(bp, false, type, weight); + WARN_ON(toggle_bp_slot(bp, false, type, weight)); } void release_bp_slot(struct perf_event *bp) { - mutex_lock(&nr_bp_mutex); + struct mutex *mtx = bp_constraints_lock(bp); arch_unregister_hw_breakpoint(bp); __release_bp_slot(bp, bp->attr.bp_type); - - mutex_unlock(&nr_bp_mutex); + bp_constraints_unlock(mtx); } static int __modify_bp_slot(struct perf_event *bp, u64 old_type, u64 new_type) @@ -372,11 +674,10 @@ static int __modify_bp_slot(struct perf_event *bp, u64 old_type, u64 new_type) static int modify_bp_slot(struct perf_event *bp, u64 old_type, u64 new_type) { - int ret; + struct mutex *mtx = bp_constraints_lock(bp); + int ret = __modify_bp_slot(bp, old_type, new_type); - mutex_lock(&nr_bp_mutex); - ret = __modify_bp_slot(bp, old_type, new_type); - mutex_unlock(&nr_bp_mutex); + bp_constraints_unlock(mtx); return ret; } @@ -387,18 +688,28 @@ static int modify_bp_slot(struct perf_event *bp, u64 old_type, u64 new_type) */ int dbg_reserve_bp_slot(struct perf_event *bp) { - if (mutex_is_locked(&nr_bp_mutex)) + int ret; + + if (bp_constraints_is_locked(bp)) return -1; - return __reserve_bp_slot(bp, bp->attr.bp_type); + /* Locks aren't held; disable lockdep assert checking. */ + lockdep_off(); + ret = __reserve_bp_slot(bp, bp->attr.bp_type); + lockdep_on(); + + return ret; } int dbg_release_bp_slot(struct perf_event *bp) { - if (mutex_is_locked(&nr_bp_mutex)) + if (bp_constraints_is_locked(bp)) return -1; + /* Locks aren't held; disable lockdep assert checking. */ + lockdep_off(); __release_bp_slot(bp, bp->attr.bp_type); + lockdep_on(); return 0; } @@ -604,6 +915,50 @@ void unregister_wide_hw_breakpoint(struct perf_event * __percpu *cpu_events) } EXPORT_SYMBOL_GPL(unregister_wide_hw_breakpoint); +/** + * hw_breakpoint_is_used - check if breakpoints are currently used + * + * Returns: true if breakpoints are used, false otherwise. + */ +bool hw_breakpoint_is_used(void) +{ + int cpu; + + if (!constraints_initialized) + return false; + + for_each_possible_cpu(cpu) { + for (int type = 0; type < TYPE_MAX; ++type) { + struct bp_cpuinfo *info = get_bp_info(cpu, type); + + if (info->cpu_pinned) + return true; + + for (int slot = 0; slot < hw_breakpoint_slots_cached(type); ++slot) { + if (atomic_read(&info->tsk_pinned.count[slot])) + return true; + } + } + } + + for (int type = 0; type < TYPE_MAX; ++type) { + for (int slot = 0; slot < hw_breakpoint_slots_cached(type); ++slot) { + /* + * Warn, because if there are CPU pinned counters, + * should never get here; bp_cpuinfo::cpu_pinned should + * be consistent with the global cpu_pinned histogram. + */ + if (WARN_ON(atomic_read(&cpu_pinned[type].count[slot]))) + return true; + + if (atomic_read(&tsk_pinned_all[type].count[slot])) + return true; + } + } + + return false; +} + static struct notifier_block hw_breakpoint_exceptions_nb = { .notifier_call = hw_breakpoint_exceptions_notify, /* we need to be notified first */ @@ -678,38 +1033,19 @@ static struct pmu perf_breakpoint = { int __init init_hw_breakpoint(void) { - int cpu, err_cpu; - int i; - - for (i = 0; i < TYPE_MAX; i++) - nr_slots[i] = hw_breakpoint_slots(i); + int ret; - for_each_possible_cpu(cpu) { - for (i = 0; i < TYPE_MAX; i++) { - struct bp_cpuinfo *info = get_bp_info(cpu, i); + ret = rhltable_init(&task_bps_ht, &task_bps_ht_params); + if (ret) + return ret; - info->tsk_pinned = kcalloc(nr_slots[i], sizeof(int), - GFP_KERNEL); - if (!info->tsk_pinned) - goto err_alloc; - } - } + ret = init_breakpoint_slots(); + if (ret) + return ret; - constraints_initialized = 1; + constraints_initialized = true; perf_pmu_register(&perf_breakpoint, "breakpoint", PERF_TYPE_BREAKPOINT); return register_die_notifier(&hw_breakpoint_exceptions_nb); - - err_alloc: - for_each_possible_cpu(err_cpu) { - for (i = 0; i < TYPE_MAX; i++) - kfree(get_bp_info(err_cpu, i)->tsk_pinned); - if (err_cpu == cpu) - break; - } - - return -ENOMEM; } - - diff --git a/kernel/events/hw_breakpoint_test.c b/kernel/events/hw_breakpoint_test.c new file mode 100644 index 000000000000..5ced822df788 --- /dev/null +++ b/kernel/events/hw_breakpoint_test.c @@ -0,0 +1,333 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * KUnit test for hw_breakpoint constraints accounting logic. + * + * Copyright (C) 2022, Google LLC. + */ + +#include <kunit/test.h> +#include <linux/cpumask.h> +#include <linux/hw_breakpoint.h> +#include <linux/kthread.h> +#include <linux/perf_event.h> +#include <asm/hw_breakpoint.h> + +#define TEST_REQUIRES_BP_SLOTS(test, slots) \ + do { \ + if ((slots) > get_test_bp_slots()) { \ + kunit_skip((test), "Requires breakpoint slots: %d > %d", slots, \ + get_test_bp_slots()); \ + } \ + } while (0) + +#define TEST_EXPECT_NOSPC(expr) KUNIT_EXPECT_EQ(test, -ENOSPC, PTR_ERR(expr)) + +#define MAX_TEST_BREAKPOINTS 512 + +static char break_vars[MAX_TEST_BREAKPOINTS]; +static struct perf_event *test_bps[MAX_TEST_BREAKPOINTS]; +static struct task_struct *__other_task; + +static struct perf_event *register_test_bp(int cpu, struct task_struct *tsk, int idx) +{ + struct perf_event_attr attr = {}; + + if (WARN_ON(idx < 0 || idx >= MAX_TEST_BREAKPOINTS)) + return NULL; + + hw_breakpoint_init(&attr); + attr.bp_addr = (unsigned long)&break_vars[idx]; + attr.bp_len = HW_BREAKPOINT_LEN_1; + attr.bp_type = HW_BREAKPOINT_RW; + return perf_event_create_kernel_counter(&attr, cpu, tsk, NULL, NULL); +} + +static void unregister_test_bp(struct perf_event **bp) +{ + if (WARN_ON(IS_ERR(*bp))) + return; + if (WARN_ON(!*bp)) + return; + unregister_hw_breakpoint(*bp); + *bp = NULL; +} + +static int get_test_bp_slots(void) +{ + static int slots; + + if (!slots) + slots = hw_breakpoint_slots(TYPE_DATA); + + return slots; +} + +static void fill_one_bp_slot(struct kunit *test, int *id, int cpu, struct task_struct *tsk) +{ + struct perf_event *bp = register_test_bp(cpu, tsk, *id); + + KUNIT_ASSERT_NOT_NULL(test, bp); + KUNIT_ASSERT_FALSE(test, IS_ERR(bp)); + KUNIT_ASSERT_NULL(test, test_bps[*id]); + test_bps[(*id)++] = bp; +} + +/* + * Fills up the given @cpu/@tsk with breakpoints, only leaving @skip slots free. + * + * Returns true if this can be called again, continuing at @id. + */ +static bool fill_bp_slots(struct kunit *test, int *id, int cpu, struct task_struct *tsk, int skip) +{ + for (int i = 0; i < get_test_bp_slots() - skip; ++i) + fill_one_bp_slot(test, id, cpu, tsk); + + return *id + get_test_bp_slots() <= MAX_TEST_BREAKPOINTS; +} + +static int dummy_kthread(void *arg) +{ + return 0; +} + +static struct task_struct *get_other_task(struct kunit *test) +{ + struct task_struct *tsk; + + if (__other_task) + return __other_task; + + tsk = kthread_create(dummy_kthread, NULL, "hw_breakpoint_dummy_task"); + KUNIT_ASSERT_FALSE(test, IS_ERR(tsk)); + __other_task = tsk; + return __other_task; +} + +static int get_test_cpu(int num) +{ + int cpu; + + WARN_ON(num < 0); + + for_each_online_cpu(cpu) { + if (num-- <= 0) + break; + } + + return cpu; +} + +/* ===== Test cases ===== */ + +static void test_one_cpu(struct kunit *test) +{ + int idx = 0; + + fill_bp_slots(test, &idx, get_test_cpu(0), NULL, 0); + TEST_EXPECT_NOSPC(register_test_bp(-1, current, idx)); + TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), NULL, idx)); +} + +static void test_many_cpus(struct kunit *test) +{ + int idx = 0; + int cpu; + + /* Test that CPUs are independent. */ + for_each_online_cpu(cpu) { + bool do_continue = fill_bp_slots(test, &idx, cpu, NULL, 0); + + TEST_EXPECT_NOSPC(register_test_bp(cpu, NULL, idx)); + if (!do_continue) + break; + } +} + +static void test_one_task_on_all_cpus(struct kunit *test) +{ + int idx = 0; + + fill_bp_slots(test, &idx, -1, current, 0); + TEST_EXPECT_NOSPC(register_test_bp(-1, current, idx)); + TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), current, idx)); + TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), NULL, idx)); + /* Remove one and adding back CPU-target should work. */ + unregister_test_bp(&test_bps[0]); + fill_one_bp_slot(test, &idx, get_test_cpu(0), NULL); +} + +static void test_two_tasks_on_all_cpus(struct kunit *test) +{ + int idx = 0; + + /* Test that tasks are independent. */ + fill_bp_slots(test, &idx, -1, current, 0); + fill_bp_slots(test, &idx, -1, get_other_task(test), 0); + + TEST_EXPECT_NOSPC(register_test_bp(-1, current, idx)); + TEST_EXPECT_NOSPC(register_test_bp(-1, get_other_task(test), idx)); + TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), current, idx)); + TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), get_other_task(test), idx)); + TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), NULL, idx)); + /* Remove one from first task and adding back CPU-target should not work. */ + unregister_test_bp(&test_bps[0]); + TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), NULL, idx)); +} + +static void test_one_task_on_one_cpu(struct kunit *test) +{ + int idx = 0; + + fill_bp_slots(test, &idx, get_test_cpu(0), current, 0); + TEST_EXPECT_NOSPC(register_test_bp(-1, current, idx)); + TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), current, idx)); + TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), NULL, idx)); + /* + * Remove one and adding back CPU-target should work; this case is + * special vs. above because the task's constraints are CPU-dependent. + */ + unregister_test_bp(&test_bps[0]); + fill_one_bp_slot(test, &idx, get_test_cpu(0), NULL); +} + +static void test_one_task_mixed(struct kunit *test) +{ + int idx = 0; + + TEST_REQUIRES_BP_SLOTS(test, 3); + + fill_one_bp_slot(test, &idx, get_test_cpu(0), current); + fill_bp_slots(test, &idx, -1, current, 1); + TEST_EXPECT_NOSPC(register_test_bp(-1, current, idx)); + TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), current, idx)); + TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), NULL, idx)); + + /* Transition from CPU-dependent pinned count to CPU-independent. */ + unregister_test_bp(&test_bps[0]); + unregister_test_bp(&test_bps[1]); + fill_one_bp_slot(test, &idx, get_test_cpu(0), NULL); + fill_one_bp_slot(test, &idx, get_test_cpu(0), NULL); + TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), NULL, idx)); +} + +static void test_two_tasks_on_one_cpu(struct kunit *test) +{ + int idx = 0; + + fill_bp_slots(test, &idx, get_test_cpu(0), current, 0); + fill_bp_slots(test, &idx, get_test_cpu(0), get_other_task(test), 0); + + TEST_EXPECT_NOSPC(register_test_bp(-1, current, idx)); + TEST_EXPECT_NOSPC(register_test_bp(-1, get_other_task(test), idx)); + TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), current, idx)); + TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), get_other_task(test), idx)); + TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), NULL, idx)); + /* Can still create breakpoints on some other CPU. */ + fill_bp_slots(test, &idx, get_test_cpu(1), NULL, 0); +} + +static void test_two_tasks_on_one_all_cpus(struct kunit *test) +{ + int idx = 0; + + fill_bp_slots(test, &idx, get_test_cpu(0), current, 0); + fill_bp_slots(test, &idx, -1, get_other_task(test), 0); + + TEST_EXPECT_NOSPC(register_test_bp(-1, current, idx)); + TEST_EXPECT_NOSPC(register_test_bp(-1, get_other_task(test), idx)); + TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), current, idx)); + TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), get_other_task(test), idx)); + TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), NULL, idx)); + /* Cannot create breakpoints on some other CPU either. */ + TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(1), NULL, idx)); +} + +static void test_task_on_all_and_one_cpu(struct kunit *test) +{ + int tsk_on_cpu_idx, cpu_idx; + int idx = 0; + + TEST_REQUIRES_BP_SLOTS(test, 3); + + fill_bp_slots(test, &idx, -1, current, 2); + /* Transitioning from only all CPU breakpoints to mixed. */ + tsk_on_cpu_idx = idx; + fill_one_bp_slot(test, &idx, get_test_cpu(0), current); + fill_one_bp_slot(test, &idx, -1, current); + + TEST_EXPECT_NOSPC(register_test_bp(-1, current, idx)); + TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), current, idx)); + TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), NULL, idx)); + + /* We should still be able to use up another CPU's slots. */ + cpu_idx = idx; + fill_one_bp_slot(test, &idx, get_test_cpu(1), NULL); + TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(1), NULL, idx)); + + /* Transitioning back to task target on all CPUs. */ + unregister_test_bp(&test_bps[tsk_on_cpu_idx]); + /* Still have a CPU target breakpoint in get_test_cpu(1). */ + TEST_EXPECT_NOSPC(register_test_bp(-1, current, idx)); + /* Remove it and try again. */ + unregister_test_bp(&test_bps[cpu_idx]); + fill_one_bp_slot(test, &idx, -1, current); + + TEST_EXPECT_NOSPC(register_test_bp(-1, current, idx)); + TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), current, idx)); + TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), NULL, idx)); + TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(1), NULL, idx)); +} + +static struct kunit_case hw_breakpoint_test_cases[] = { + KUNIT_CASE(test_one_cpu), + KUNIT_CASE(test_many_cpus), + KUNIT_CASE(test_one_task_on_all_cpus), + KUNIT_CASE(test_two_tasks_on_all_cpus), + KUNIT_CASE(test_one_task_on_one_cpu), + KUNIT_CASE(test_one_task_mixed), + KUNIT_CASE(test_two_tasks_on_one_cpu), + KUNIT_CASE(test_two_tasks_on_one_all_cpus), + KUNIT_CASE(test_task_on_all_and_one_cpu), + {}, +}; + +static int test_init(struct kunit *test) +{ + /* Most test cases want 2 distinct CPUs. */ + if (num_online_cpus() < 2) + return -EINVAL; + + /* Want the system to not use breakpoints elsewhere. */ + if (hw_breakpoint_is_used()) + return -EBUSY; + + return 0; +} + +static void test_exit(struct kunit *test) +{ + for (int i = 0; i < MAX_TEST_BREAKPOINTS; ++i) { + if (test_bps[i]) + unregister_test_bp(&test_bps[i]); + } + + if (__other_task) { + kthread_stop(__other_task); + __other_task = NULL; + } + + /* Verify that internal state agrees that no breakpoints are in use. */ + KUNIT_EXPECT_FALSE(test, hw_breakpoint_is_used()); +} + +static struct kunit_suite hw_breakpoint_test_suite = { + .name = "hw_breakpoint", + .test_cases = hw_breakpoint_test_cases, + .init = test_init, + .exit = test_exit, +}; + +kunit_test_suites(&hw_breakpoint_test_suite); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Marco Elver <elver@google.com>"); |