diff options
Diffstat (limited to 'arch/s390/kernel/perf_cpum_sf.c')
| -rw-r--r-- | arch/s390/kernel/perf_cpum_sf.c | 2100 |
1 files changed, 2100 insertions, 0 deletions
diff --git a/arch/s390/kernel/perf_cpum_sf.c b/arch/s390/kernel/perf_cpum_sf.c new file mode 100644 index 000000000..c8e1e3252 --- /dev/null +++ b/arch/s390/kernel/perf_cpum_sf.c @@ -0,0 +1,2100 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Performance event support for the System z CPU-measurement Sampling Facility + * + * Copyright IBM Corp. 2013, 2018 + * Author(s): Hendrik Brueckner <brueckner@linux.vnet.ibm.com> + */ +#define KMSG_COMPONENT "cpum_sf" +#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt + +#include <linux/kernel.h> +#include <linux/kernel_stat.h> +#include <linux/perf_event.h> +#include <linux/percpu.h> +#include <linux/pid.h> +#include <linux/notifier.h> +#include <linux/export.h> +#include <linux/slab.h> +#include <linux/mm.h> +#include <linux/moduleparam.h> +#include <asm/cpu_mf.h> +#include <asm/irq.h> +#include <asm/debug.h> +#include <asm/timex.h> + +/* Minimum number of sample-data-block-tables: + * At least one table is required for the sampling buffer structure. + * A single table contains up to 511 pointers to sample-data-blocks. + */ +#define CPUM_SF_MIN_SDBT 1 + +/* Number of sample-data-blocks per sample-data-block-table (SDBT): + * A table contains SDB pointers (8 bytes) and one table-link entry + * that points to the origin of the next SDBT. + */ +#define CPUM_SF_SDB_PER_TABLE ((PAGE_SIZE - 8) / 8) + +/* Maximum page offset for an SDBT table-link entry: + * If this page offset is reached, a table-link entry to the next SDBT + * must be added. + */ +#define CPUM_SF_SDBT_TL_OFFSET (CPUM_SF_SDB_PER_TABLE * 8) +static inline int require_table_link(const void *sdbt) +{ + return ((unsigned long) sdbt & ~PAGE_MASK) == CPUM_SF_SDBT_TL_OFFSET; +} + +/* Minimum and maximum sampling buffer sizes: + * + * This number represents the maximum size of the sampling buffer taking + * the number of sample-data-block-tables into account. Note that these + * numbers apply to the basic-sampling function only. + * The maximum number of SDBs is increased by CPUM_SF_SDB_DIAG_FACTOR if + * the diagnostic-sampling function is active. + * + * Sampling buffer size Buffer characteristics + * --------------------------------------------------- + * 64KB == 16 pages (4KB per page) + * 1 page for SDB-tables + * 15 pages for SDBs + * + * 32MB == 8192 pages (4KB per page) + * 16 pages for SDB-tables + * 8176 pages for SDBs + */ +static unsigned long __read_mostly CPUM_SF_MIN_SDB = 15; +static unsigned long __read_mostly CPUM_SF_MAX_SDB = 8176; +static unsigned long __read_mostly CPUM_SF_SDB_DIAG_FACTOR = 1; + +struct sf_buffer { + unsigned long *sdbt; /* Sample-data-block-table origin */ + /* buffer characteristics (required for buffer increments) */ + unsigned long num_sdb; /* Number of sample-data-blocks */ + unsigned long num_sdbt; /* Number of sample-data-block-tables */ + unsigned long *tail; /* last sample-data-block-table */ +}; + +struct aux_buffer { + struct sf_buffer sfb; + unsigned long head; /* index of SDB of buffer head */ + unsigned long alert_mark; /* index of SDB of alert request position */ + unsigned long empty_mark; /* mark of SDB not marked full */ + unsigned long *sdb_index; /* SDB address for fast lookup */ + unsigned long *sdbt_index; /* SDBT address for fast lookup */ +}; + +struct cpu_hw_sf { + /* CPU-measurement sampling information block */ + struct hws_qsi_info_block qsi; + /* CPU-measurement sampling control block */ + struct hws_lsctl_request_block lsctl; + struct sf_buffer sfb; /* Sampling buffer */ + unsigned int flags; /* Status flags */ + struct perf_event *event; /* Scheduled perf event */ + struct perf_output_handle handle; /* AUX buffer output handle */ +}; +static DEFINE_PER_CPU(struct cpu_hw_sf, cpu_hw_sf); + +/* Debug feature */ +static debug_info_t *sfdbg; + +/* + * sf_disable() - Switch off sampling facility + */ +static int sf_disable(void) +{ + struct hws_lsctl_request_block sreq; + + memset(&sreq, 0, sizeof(sreq)); + return lsctl(&sreq); +} + +/* + * sf_buffer_available() - Check for an allocated sampling buffer + */ +static int sf_buffer_available(struct cpu_hw_sf *cpuhw) +{ + return !!cpuhw->sfb.sdbt; +} + +/* + * deallocate sampling facility buffer + */ +static void free_sampling_buffer(struct sf_buffer *sfb) +{ + unsigned long *sdbt, *curr; + + if (!sfb->sdbt) + return; + + sdbt = sfb->sdbt; + curr = sdbt; + + /* Free the SDBT after all SDBs are processed... */ + while (1) { + if (!*curr || !sdbt) + break; + + /* Process table-link entries */ + if (is_link_entry(curr)) { + curr = get_next_sdbt(curr); + if (sdbt) + free_page((unsigned long) sdbt); + + /* If the origin is reached, sampling buffer is freed */ + if (curr == sfb->sdbt) + break; + else + sdbt = curr; + } else { + /* Process SDB pointer */ + if (*curr) { + free_page(*curr); + curr++; + } + } + } + + debug_sprintf_event(sfdbg, 5, + "free_sampling_buffer: freed sdbt=%p\n", sfb->sdbt); + memset(sfb, 0, sizeof(*sfb)); +} + +static int alloc_sample_data_block(unsigned long *sdbt, gfp_t gfp_flags) +{ + unsigned long sdb, *trailer; + + /* Allocate and initialize sample-data-block */ + sdb = get_zeroed_page(gfp_flags); + if (!sdb) + return -ENOMEM; + trailer = trailer_entry_ptr(sdb); + *trailer = SDB_TE_ALERT_REQ_MASK; + + /* Link SDB into the sample-data-block-table */ + *sdbt = sdb; + + return 0; +} + +/* + * realloc_sampling_buffer() - extend sampler memory + * + * Allocates new sample-data-blocks and adds them to the specified sampling + * buffer memory. + * + * Important: This modifies the sampling buffer and must be called when the + * sampling facility is disabled. + * + * Returns zero on success, non-zero otherwise. + */ +static int realloc_sampling_buffer(struct sf_buffer *sfb, + unsigned long num_sdb, gfp_t gfp_flags) +{ + int i, rc; + unsigned long *new, *tail, *tail_prev = NULL; + + if (!sfb->sdbt || !sfb->tail) + return -EINVAL; + + if (!is_link_entry(sfb->tail)) + return -EINVAL; + + /* Append to the existing sampling buffer, overwriting the table-link + * register. + * The tail variables always points to the "tail" (last and table-link) + * entry in an SDB-table. + */ + tail = sfb->tail; + + /* Do a sanity check whether the table-link entry points to + * the sampling buffer origin. + */ + if (sfb->sdbt != get_next_sdbt(tail)) { + debug_sprintf_event(sfdbg, 3, "realloc_sampling_buffer: " + "sampling buffer is not linked: origin=%p" + "tail=%p\n", + (void *) sfb->sdbt, (void *) tail); + return -EINVAL; + } + + /* Allocate remaining SDBs */ + rc = 0; + for (i = 0; i < num_sdb; i++) { + /* Allocate a new SDB-table if it is full. */ + if (require_table_link(tail)) { + new = (unsigned long *) get_zeroed_page(gfp_flags); + if (!new) { + rc = -ENOMEM; + break; + } + sfb->num_sdbt++; + /* Link current page to tail of chain */ + *tail = (unsigned long)(void *) new + 1; + tail_prev = tail; + tail = new; + } + + /* Allocate a new sample-data-block. + * If there is not enough memory, stop the realloc process + * and simply use what was allocated. If this is a temporary + * issue, a new realloc call (if required) might succeed. + */ + rc = alloc_sample_data_block(tail, gfp_flags); + if (rc) { + /* Undo last SDBT. An SDBT with no SDB at its first + * entry but with an SDBT entry instead can not be + * handled by the interrupt handler code. + * Avoid this situation. + */ + if (tail_prev) { + sfb->num_sdbt--; + free_page((unsigned long) new); + tail = tail_prev; + } + break; + } + sfb->num_sdb++; + tail++; + tail_prev = new = NULL; /* Allocated at least one SBD */ + } + + /* Link sampling buffer to its origin */ + *tail = (unsigned long) sfb->sdbt + 1; + sfb->tail = tail; + + debug_sprintf_event(sfdbg, 4, "realloc_sampling_buffer: new buffer" + " settings: sdbt=%lu sdb=%lu\n", + sfb->num_sdbt, sfb->num_sdb); + return rc; +} + +/* + * allocate_sampling_buffer() - allocate sampler memory + * + * Allocates and initializes a sampling buffer structure using the + * specified number of sample-data-blocks (SDB). For each allocation, + * a 4K page is used. The number of sample-data-block-tables (SDBT) + * are calculated from SDBs. + * Also set the ALERT_REQ mask in each SDBs trailer. + * + * Returns zero on success, non-zero otherwise. + */ +static int alloc_sampling_buffer(struct sf_buffer *sfb, unsigned long num_sdb) +{ + int rc; + + if (sfb->sdbt) + return -EINVAL; + + /* Allocate the sample-data-block-table origin */ + sfb->sdbt = (unsigned long *) get_zeroed_page(GFP_KERNEL); + if (!sfb->sdbt) + return -ENOMEM; + sfb->num_sdb = 0; + sfb->num_sdbt = 1; + + /* Link the table origin to point to itself to prepare for + * realloc_sampling_buffer() invocation. + */ + sfb->tail = sfb->sdbt; + *sfb->tail = (unsigned long)(void *) sfb->sdbt + 1; + + /* Allocate requested number of sample-data-blocks */ + rc = realloc_sampling_buffer(sfb, num_sdb, GFP_KERNEL); + if (rc) { + free_sampling_buffer(sfb); + debug_sprintf_event(sfdbg, 4, "alloc_sampling_buffer: " + "realloc_sampling_buffer failed with rc=%i\n", rc); + } else + debug_sprintf_event(sfdbg, 4, + "alloc_sampling_buffer: tear=%p dear=%p\n", + sfb->sdbt, (void *) *sfb->sdbt); + return rc; +} + +static void sfb_set_limits(unsigned long min, unsigned long max) +{ + struct hws_qsi_info_block si; + + CPUM_SF_MIN_SDB = min; + CPUM_SF_MAX_SDB = max; + + memset(&si, 0, sizeof(si)); + if (!qsi(&si)) + CPUM_SF_SDB_DIAG_FACTOR = DIV_ROUND_UP(si.dsdes, si.bsdes); +} + +static unsigned long sfb_max_limit(struct hw_perf_event *hwc) +{ + return SAMPL_DIAG_MODE(hwc) ? CPUM_SF_MAX_SDB * CPUM_SF_SDB_DIAG_FACTOR + : CPUM_SF_MAX_SDB; +} + +static unsigned long sfb_pending_allocs(struct sf_buffer *sfb, + struct hw_perf_event *hwc) +{ + if (!sfb->sdbt) + return SFB_ALLOC_REG(hwc); + if (SFB_ALLOC_REG(hwc) > sfb->num_sdb) + return SFB_ALLOC_REG(hwc) - sfb->num_sdb; + return 0; +} + +static int sfb_has_pending_allocs(struct sf_buffer *sfb, + struct hw_perf_event *hwc) +{ + return sfb_pending_allocs(sfb, hwc) > 0; +} + +static void sfb_account_allocs(unsigned long num, struct hw_perf_event *hwc) +{ + /* Limit the number of SDBs to not exceed the maximum */ + num = min_t(unsigned long, num, sfb_max_limit(hwc) - SFB_ALLOC_REG(hwc)); + if (num) + SFB_ALLOC_REG(hwc) += num; +} + +static void sfb_init_allocs(unsigned long num, struct hw_perf_event *hwc) +{ + SFB_ALLOC_REG(hwc) = 0; + sfb_account_allocs(num, hwc); +} + +static void deallocate_buffers(struct cpu_hw_sf *cpuhw) +{ + if (cpuhw->sfb.sdbt) + free_sampling_buffer(&cpuhw->sfb); +} + +static int allocate_buffers(struct cpu_hw_sf *cpuhw, struct hw_perf_event *hwc) +{ + unsigned long n_sdb, freq, factor; + size_t sample_size; + + /* Calculate sampling buffers using 4K pages + * + * 1. Determine the sample data size which depends on the used + * sampling functions, for example, basic-sampling or + * basic-sampling with diagnostic-sampling. + * + * 2. Use the sampling frequency as input. The sampling buffer is + * designed for almost one second. This can be adjusted through + * the "factor" variable. + * In any case, alloc_sampling_buffer() sets the Alert Request + * Control indicator to trigger a measurement-alert to harvest + * sample-data-blocks (sdb). + * + * 3. Compute the number of sample-data-blocks and ensure a minimum + * of CPUM_SF_MIN_SDB. Also ensure the upper limit does not + * exceed a "calculated" maximum. The symbolic maximum is + * designed for basic-sampling only and needs to be increased if + * diagnostic-sampling is active. + * See also the remarks for these symbolic constants. + * + * 4. Compute the number of sample-data-block-tables (SDBT) and + * ensure a minimum of CPUM_SF_MIN_SDBT (one table can manage up + * to 511 SDBs). + */ + sample_size = sizeof(struct hws_basic_entry); + freq = sample_rate_to_freq(&cpuhw->qsi, SAMPL_RATE(hwc)); + factor = 1; + n_sdb = DIV_ROUND_UP(freq, factor * ((PAGE_SIZE-64) / sample_size)); + if (n_sdb < CPUM_SF_MIN_SDB) + n_sdb = CPUM_SF_MIN_SDB; + + /* If there is already a sampling buffer allocated, it is very likely + * that the sampling facility is enabled too. If the event to be + * initialized requires a greater sampling buffer, the allocation must + * be postponed. Changing the sampling buffer requires the sampling + * facility to be in the disabled state. So, account the number of + * required SDBs and let cpumsf_pmu_enable() resize the buffer just + * before the event is started. + */ + sfb_init_allocs(n_sdb, hwc); + if (sf_buffer_available(cpuhw)) + return 0; + + debug_sprintf_event(sfdbg, 3, + "allocate_buffers: rate=%lu f=%lu sdb=%lu/%lu" + " sample_size=%lu cpuhw=%p\n", + SAMPL_RATE(hwc), freq, n_sdb, sfb_max_limit(hwc), + sample_size, cpuhw); + + return alloc_sampling_buffer(&cpuhw->sfb, + sfb_pending_allocs(&cpuhw->sfb, hwc)); +} + +static unsigned long min_percent(unsigned int percent, unsigned long base, + unsigned long min) +{ + return min_t(unsigned long, min, DIV_ROUND_UP(percent * base, 100)); +} + +static unsigned long compute_sfb_extent(unsigned long ratio, unsigned long base) +{ + /* Use a percentage-based approach to extend the sampling facility + * buffer. Accept up to 5% sample data loss. + * Vary the extents between 1% to 5% of the current number of + * sample-data-blocks. + */ + if (ratio <= 5) + return 0; + if (ratio <= 25) + return min_percent(1, base, 1); + if (ratio <= 50) + return min_percent(1, base, 1); + if (ratio <= 75) + return min_percent(2, base, 2); + if (ratio <= 100) + return min_percent(3, base, 3); + if (ratio <= 250) + return min_percent(4, base, 4); + + return min_percent(5, base, 8); +} + +static void sfb_account_overflows(struct cpu_hw_sf *cpuhw, + struct hw_perf_event *hwc) +{ + unsigned long ratio, num; + + if (!OVERFLOW_REG(hwc)) + return; + + /* The sample_overflow contains the average number of sample data + * that has been lost because sample-data-blocks were full. + * + * Calculate the total number of sample data entries that has been + * discarded. Then calculate the ratio of lost samples to total samples + * per second in percent. + */ + ratio = DIV_ROUND_UP(100 * OVERFLOW_REG(hwc) * cpuhw->sfb.num_sdb, + sample_rate_to_freq(&cpuhw->qsi, SAMPL_RATE(hwc))); + + /* Compute number of sample-data-blocks */ + num = compute_sfb_extent(ratio, cpuhw->sfb.num_sdb); + if (num) + sfb_account_allocs(num, hwc); + + debug_sprintf_event(sfdbg, 5, "sfb: overflow: overflow=%llu ratio=%lu" + " num=%lu\n", OVERFLOW_REG(hwc), ratio, num); + OVERFLOW_REG(hwc) = 0; +} + +/* extend_sampling_buffer() - Extend sampling buffer + * @sfb: Sampling buffer structure (for local CPU) + * @hwc: Perf event hardware structure + * + * Use this function to extend the sampling buffer based on the overflow counter + * and postponed allocation extents stored in the specified Perf event hardware. + * + * Important: This function disables the sampling facility in order to safely + * change the sampling buffer structure. Do not call this function + * when the PMU is active. + */ +static void extend_sampling_buffer(struct sf_buffer *sfb, + struct hw_perf_event *hwc) +{ + unsigned long num, num_old; + int rc; + + num = sfb_pending_allocs(sfb, hwc); + if (!num) + return; + num_old = sfb->num_sdb; + + /* Disable the sampling facility to reset any states and also + * clear pending measurement alerts. + */ + sf_disable(); + + /* Extend the sampling buffer. + * This memory allocation typically happens in an atomic context when + * called by perf. Because this is a reallocation, it is fine if the + * new SDB-request cannot be satisfied immediately. + */ + rc = realloc_sampling_buffer(sfb, num, GFP_ATOMIC); + if (rc) + debug_sprintf_event(sfdbg, 5, "sfb: extend: realloc " + "failed with rc=%i\n", rc); + + if (sfb_has_pending_allocs(sfb, hwc)) + debug_sprintf_event(sfdbg, 5, "sfb: extend: " + "req=%lu alloc=%lu remaining=%lu\n", + num, sfb->num_sdb - num_old, + sfb_pending_allocs(sfb, hwc)); +} + + +/* Number of perf events counting hardware events */ +static atomic_t num_events; +/* Used to avoid races in calling reserve/release_cpumf_hardware */ +static DEFINE_MUTEX(pmc_reserve_mutex); + +#define PMC_INIT 0 +#define PMC_RELEASE 1 +#define PMC_FAILURE 2 +static void setup_pmc_cpu(void *flags) +{ + int err; + struct cpu_hw_sf *cpusf = this_cpu_ptr(&cpu_hw_sf); + + err = 0; + switch (*((int *) flags)) { + case PMC_INIT: + memset(cpusf, 0, sizeof(*cpusf)); + err = qsi(&cpusf->qsi); + if (err) + break; + cpusf->flags |= PMU_F_RESERVED; + err = sf_disable(); + if (err) + pr_err("Switching off the sampling facility failed " + "with rc=%i\n", err); + debug_sprintf_event(sfdbg, 5, + "setup_pmc_cpu: initialized: cpuhw=%p\n", cpusf); + break; + case PMC_RELEASE: + cpusf->flags &= ~PMU_F_RESERVED; + err = sf_disable(); + if (err) { + pr_err("Switching off the sampling facility failed " + "with rc=%i\n", err); + } else + deallocate_buffers(cpusf); + debug_sprintf_event(sfdbg, 5, + "setup_pmc_cpu: released: cpuhw=%p\n", cpusf); + break; + } + if (err) + *((int *) flags) |= PMC_FAILURE; +} + +static void release_pmc_hardware(void) +{ + int flags = PMC_RELEASE; + + irq_subclass_unregister(IRQ_SUBCLASS_MEASUREMENT_ALERT); + on_each_cpu(setup_pmc_cpu, &flags, 1); +} + +static int reserve_pmc_hardware(void) +{ + int flags = PMC_INIT; + + on_each_cpu(setup_pmc_cpu, &flags, 1); + if (flags & PMC_FAILURE) { + release_pmc_hardware(); + return -ENODEV; + } + irq_subclass_register(IRQ_SUBCLASS_MEASUREMENT_ALERT); + + return 0; +} + +static void hw_perf_event_destroy(struct perf_event *event) +{ + /* Release PMC if this is the last perf 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); + } +} + +static void hw_init_period(struct hw_perf_event *hwc, u64 period) +{ + hwc->sample_period = period; + hwc->last_period = hwc->sample_period; + local64_set(&hwc->period_left, hwc->sample_period); +} + +static void hw_reset_registers(struct hw_perf_event *hwc, + unsigned long *sdbt_origin) +{ + /* (Re)set to first sample-data-block-table */ + TEAR_REG(hwc) = (unsigned long) sdbt_origin; +} + +static unsigned long hw_limit_rate(const struct hws_qsi_info_block *si, + unsigned long rate) +{ + return clamp_t(unsigned long, rate, + si->min_sampl_rate, si->max_sampl_rate); +} + +static u32 cpumsf_pid_type(struct perf_event *event, + u32 pid, enum pid_type type) +{ + struct task_struct *tsk; + + /* Idle process */ + if (!pid) + goto out; + + tsk = find_task_by_pid_ns(pid, &init_pid_ns); + pid = -1; + if (tsk) { + /* + * Only top level events contain the pid namespace in which + * they are created. + */ + if (event->parent) + event = event->parent; + pid = __task_pid_nr_ns(tsk, type, event->ns); + /* + * See also 1d953111b648 + * "perf/core: Don't report zero PIDs for exiting tasks". + */ + if (!pid && !pid_alive(tsk)) + pid = -1; + } +out: + return pid; +} + +static void cpumsf_output_event_pid(struct perf_event *event, + struct perf_sample_data *data, + struct pt_regs *regs) +{ + u32 pid; + struct perf_event_header header; + struct perf_output_handle handle; + + /* + * Obtain the PID from the basic-sampling data entry and + * correct the data->tid_entry.pid value. + */ + pid = data->tid_entry.pid; + + /* Protect callchain buffers, tasks */ + rcu_read_lock(); + + perf_prepare_sample(&header, data, event, regs); + if (perf_output_begin(&handle, event, header.size)) + goto out; + + /* Update the process ID (see also kernel/events/core.c) */ + data->tid_entry.pid = cpumsf_pid_type(event, pid, PIDTYPE_TGID); + data->tid_entry.tid = cpumsf_pid_type(event, pid, PIDTYPE_PID); + + perf_output_sample(&handle, &header, data, event); + perf_output_end(&handle); +out: + rcu_read_unlock(); +} + +static int __hw_perf_event_init(struct perf_event *event) +{ + struct cpu_hw_sf *cpuhw; + struct hws_qsi_info_block si; + struct perf_event_attr *attr = &event->attr; + struct hw_perf_event *hwc = &event->hw; + unsigned long rate; + int cpu, err; + + /* Reserve CPU-measurement sampling facility */ + err = 0; + if (!atomic_inc_not_zero(&num_events)) { + mutex_lock(&pmc_reserve_mutex); + if (atomic_read(&num_events) == 0 && reserve_pmc_hardware()) + err = -EBUSY; + else + atomic_inc(&num_events); + mutex_unlock(&pmc_reserve_mutex); + } + event->destroy = hw_perf_event_destroy; + + if (err) + goto out; + + /* Access per-CPU sampling information (query sampling info) */ + /* + * The event->cpu value can be -1 to count on every CPU, for example, + * when attaching to a task. If this is specified, use the query + * sampling info from the current CPU, otherwise use event->cpu to + * retrieve the per-CPU information. + * Later, cpuhw indicates whether to allocate sampling buffers for a + * particular CPU (cpuhw!=NULL) or each online CPU (cpuw==NULL). + */ + memset(&si, 0, sizeof(si)); + cpuhw = NULL; + if (event->cpu == -1) + qsi(&si); + else { + /* Event is pinned to a particular CPU, retrieve the per-CPU + * sampling structure for accessing the CPU-specific QSI. + */ + cpuhw = &per_cpu(cpu_hw_sf, event->cpu); + si = cpuhw->qsi; + } + + /* Check sampling facility authorization and, if not authorized, + * fall back to other PMUs. It is safe to check any CPU because + * the authorization is identical for all configured CPUs. + */ + if (!si.as) { + err = -ENOENT; + goto out; + } + + /* Always enable basic sampling */ + SAMPL_FLAGS(hwc) = PERF_CPUM_SF_BASIC_MODE; + + /* Check if diagnostic sampling is requested. Deny if the required + * sampling authorization is missing. + */ + if (attr->config == PERF_EVENT_CPUM_SF_DIAG) { + if (!si.ad) { + err = -EPERM; + goto out; + } + SAMPL_FLAGS(hwc) |= PERF_CPUM_SF_DIAG_MODE; + } + + /* Check and set other sampling flags */ + if (attr->config1 & PERF_CPUM_SF_FULL_BLOCKS) + SAMPL_FLAGS(hwc) |= PERF_CPUM_SF_FULL_BLOCKS; + + /* The sampling information (si) contains information about the + * min/max sampling intervals and the CPU speed. So calculate the + * correct sampling interval and avoid the whole period adjust + * feedback loop. + */ + rate = 0; + if (attr->freq) { + if (!attr->sample_freq) { + err = -EINVAL; + goto out; + } + rate = freq_to_sample_rate(&si, attr->sample_freq); + rate = hw_limit_rate(&si, rate); + attr->freq = 0; + attr->sample_period = rate; + } else { + /* The min/max sampling rates specifies the valid range + * of sample periods. If the specified sample period is + * out of range, limit the period to the range boundary. + */ + rate = hw_limit_rate(&si, hwc->sample_period); + + /* The perf core maintains a maximum sample rate that is + * configurable through the sysctl interface. Ensure the + * sampling rate does not exceed this value. This also helps + * to avoid throttling when pushing samples with + * perf_event_overflow(). + */ + if (sample_rate_to_freq(&si, rate) > + sysctl_perf_event_sample_rate) { + err = -EINVAL; + debug_sprintf_event(sfdbg, 1, "Sampling rate exceeds maximum perf sample rate\n"); + goto out; + } + } + SAMPL_RATE(hwc) = rate; + hw_init_period(hwc, SAMPL_RATE(hwc)); + + /* Initialize sample data overflow accounting */ + hwc->extra_reg.reg = REG_OVERFLOW; + OVERFLOW_REG(hwc) = 0; + + /* Use AUX buffer. No need to allocate it by ourself */ + if (attr->config == PERF_EVENT_CPUM_SF_DIAG) + return 0; + + /* Allocate the per-CPU sampling buffer using the CPU information + * from the event. If the event is not pinned to a particular + * CPU (event->cpu == -1; or cpuhw == NULL), allocate sampling + * buffers for each online CPU. + */ + if (cpuhw) + /* Event is pinned to a particular CPU */ + err = allocate_buffers(cpuhw, hwc); + else { + /* Event is not pinned, allocate sampling buffer on + * each online CPU + */ + for_each_online_cpu(cpu) { + cpuhw = &per_cpu(cpu_hw_sf, cpu); + err = allocate_buffers(cpuhw, hwc); + if (err) + break; + } + } + + /* If PID/TID sampling is active, replace the default overflow + * handler to extract and resolve the PIDs from the basic-sampling + * data entries. + */ + if (event->attr.sample_type & PERF_SAMPLE_TID) + if (is_default_overflow_handler(event)) + event->overflow_handler = cpumsf_output_event_pid; +out: + return err; +} + +static int cpumsf_pmu_event_init(struct perf_event *event) +{ + int err; + + /* No support for taken branch sampling */ + if (has_branch_stack(event)) + return -EOPNOTSUPP; + + switch (event->attr.type) { + case PERF_TYPE_RAW: + if ((event->attr.config != PERF_EVENT_CPUM_SF) && + (event->attr.config != PERF_EVENT_CPUM_SF_DIAG)) + return -ENOENT; + break; + case PERF_TYPE_HARDWARE: + /* Support sampling of CPU cycles in addition to the + * counter facility. However, the counter facility + * is more precise and, hence, restrict this PMU to + * sampling events only. + */ + if (event->attr.config != PERF_COUNT_HW_CPU_CYCLES) + return -ENOENT; + if (!is_sampling_event(event)) + return -ENOENT; + break; + default: + return -ENOENT; + } + + /* Check online status of the CPU to which the event is pinned */ + if (event->cpu >= 0 && !cpu_online(event->cpu)) + return -ENODEV; + + /* Force reset of idle/hv excludes regardless of what the + * user requested. + */ + if (event->attr.exclude_hv) + event->attr.exclude_hv = 0; + if (event->attr.exclude_idle) + event->attr.exclude_idle = 0; + + err = __hw_perf_event_init(event); + if (unlikely(err)) + if (event->destroy) + event->destroy(event); + return err; +} + +static void cpumsf_pmu_enable(struct pmu *pmu) +{ + struct cpu_hw_sf *cpuhw = this_cpu_ptr(&cpu_hw_sf); + struct hw_perf_event *hwc; + int err; + + if (cpuhw->flags & PMU_F_ENABLED) + return; + + if (cpuhw->flags & PMU_F_ERR_MASK) + return; + + /* Check whether to extent the sampling buffer. + * + * Two conditions trigger an increase of the sampling buffer for a + * perf event: + * 1. Postponed buffer allocations from the event initialization. + * 2. Sampling overflows that contribute to pending allocations. + * + * Note that the extend_sampling_buffer() function disables the sampling + * facility, but it can be fully re-enabled using sampling controls that + * have been saved in cpumsf_pmu_disable(). + */ + if (cpuhw->event) { + hwc = &cpuhw->event->hw; + if (!(SAMPL_DIAG_MODE(hwc))) { + /* + * Account number of overflow-designated + * buffer extents + */ + sfb_account_overflows(cpuhw, hwc); + if (sfb_has_pending_allocs(&cpuhw->sfb, hwc)) + extend_sampling_buffer(&cpuhw->sfb, hwc); + } + } + + /* (Re)enable the PMU and sampling facility */ + cpuhw->flags |= PMU_F_ENABLED; + barrier(); + + err = lsctl(&cpuhw->lsctl); + if (err) { + cpuhw->flags &= ~PMU_F_ENABLED; + pr_err("Loading sampling controls failed: op=%i err=%i\n", + 1, err); + return; + } + + /* Load current program parameter */ + lpp(&S390_lowcore.lpp); + + debug_sprintf_event(sfdbg, 6, "pmu_enable: es=%i cs=%i ed=%i cd=%i " + "tear=%p dear=%p\n", cpuhw->lsctl.es, cpuhw->lsctl.cs, + cpuhw->lsctl.ed, cpuhw->lsctl.cd, + (void *) cpuhw->lsctl.tear, (void *) cpuhw->lsctl.dear); +} + +static void cpumsf_pmu_disable(struct pmu *pmu) +{ + struct cpu_hw_sf *cpuhw = this_cpu_ptr(&cpu_hw_sf); + struct hws_lsctl_request_block inactive; + struct hws_qsi_info_block si; + int err; + + if (!(cpuhw->flags & PMU_F_ENABLED)) + return; + + if (cpuhw->flags & PMU_F_ERR_MASK) + return; + + /* Switch off sampling activation control */ + inactive = cpuhw->lsctl; + inactive.cs = 0; + inactive.cd = 0; + + err = lsctl(&inactive); + if (err) { + pr_err("Loading sampling controls failed: op=%i err=%i\n", + 2, err); + return; + } + + /* Save state of TEAR and DEAR register contents */ + if (!qsi(&si)) { + /* TEAR/DEAR values are valid only if the sampling facility is + * enabled. Note that cpumsf_pmu_disable() might be called even + * for a disabled sampling facility because cpumsf_pmu_enable() + * controls the enable/disable state. + */ + if (si.es) { + cpuhw->lsctl.tear = si.tear; + cpuhw->lsctl.dear = si.dear; + } + } else + debug_sprintf_event(sfdbg, 3, "cpumsf_pmu_disable: " + "qsi() failed with err=%i\n", err); + + cpuhw->flags &= ~PMU_F_ENABLED; +} + +/* perf_exclude_event() - Filter event + * @event: The perf event + * @regs: pt_regs structure + * @sde_regs: Sample-data-entry (sde) regs structure + * + * Filter perf events according to their exclude specification. + * + * Return non-zero if the event shall be excluded. + */ +static int perf_exclude_event(struct perf_event *event, struct pt_regs *regs, + struct perf_sf_sde_regs *sde_regs) +{ + if (event->attr.exclude_user && user_mode(regs)) + return 1; + if (event->attr.exclude_kernel && !user_mode(regs)) + return 1; + if (event->attr.exclude_guest && sde_regs->in_guest) + return 1; + if (event->attr.exclude_host && !sde_regs->in_guest) + return 1; + return 0; +} + +/* perf_push_sample() - Push samples to perf + * @event: The perf event + * @sample: Hardware sample data + * + * Use the hardware sample data to create perf event sample. The sample + * is the pushed to the event subsystem and the function checks for + * possible event overflows. If an event overflow occurs, the PMU is + * stopped. + * + * Return non-zero if an event overflow occurred. + */ +static int perf_push_sample(struct perf_event *event, + struct hws_basic_entry *basic) +{ + int overflow; + struct pt_regs regs; + struct perf_sf_sde_regs *sde_regs; + struct perf_sample_data data; + + /* Setup perf sample */ + perf_sample_data_init(&data, 0, event->hw.last_period); + + /* Setup pt_regs to look like an CPU-measurement external interrupt + * using the Program Request Alert code. The regs.int_parm_long + * field which is unused contains additional sample-data-entry related + * indicators. + */ + memset(®s, 0, sizeof(regs)); + regs.int_code = 0x1407; + regs.int_parm = CPU_MF_INT_SF_PRA; + sde_regs = (struct perf_sf_sde_regs *) ®s.int_parm_long; + + psw_bits(regs.psw).ia = basic->ia; + psw_bits(regs.psw).dat = basic->T; + psw_bits(regs.psw).wait = basic->W; + psw_bits(regs.psw).pstate = basic->P; + psw_bits(regs.psw).as = basic->AS; + + /* + * Use the hardware provided configuration level to decide if the + * sample belongs to a guest or host. If that is not available, + * fall back to the following heuristics: + * A non-zero guest program parameter always indicates a guest + * sample. Some early samples or samples from guests without + * lpp usage would be misaccounted to the host. We use the asn + * value as an addon heuristic to detect most of these guest samples. + * If the value differs from 0xffff (the host value), we assume to + * be a KVM guest. + */ + switch (basic->CL) { + case 1: /* logical partition */ + sde_regs->in_guest = 0; + break; + case 2: /* virtual machine */ + sde_regs->in_guest = 1; + break; + default: /* old machine, use heuristics */ + if (basic->gpp || basic->prim_asn != 0xffff) + sde_regs->in_guest = 1; + break; + } + + /* + * Store the PID value from the sample-data-entry to be + * processed and resolved by cpumsf_output_event_pid(). + */ + data.tid_entry.pid = basic->hpp & LPP_PID_MASK; + + overflow = 0; + if (perf_exclude_event(event, ®s, sde_regs)) + goto out; + if (perf_event_overflow(event, &data, ®s)) { + overflow = 1; + event->pmu->stop(event, 0); + } + perf_event_update_userpage(event); +out: + return overflow; +} + +static void perf_event_count_update(struct perf_event *event, u64 count) +{ + local64_add(count, &event->count); +} + +static void debug_sample_entry(struct hws_basic_entry *sample, + struct hws_trailer_entry *te) +{ + debug_sprintf_event(sfdbg, 4, "hw_collect_samples: Found unknown " + "sampling data entry: te->f=%i basic.def=%04x (%p)\n", + te->f, sample->def, sample); +} + +/* hw_collect_samples() - Walk through a sample-data-block and collect samples + * @event: The perf event + * @sdbt: Sample-data-block table + * @overflow: Event overflow counter + * + * Walks through a sample-data-block and collects sampling data entries that are + * then pushed to the perf event subsystem. Depending on the sampling function, + * there can be either basic-sampling or combined-sampling data entries. A + * combined-sampling data entry consists of a basic- and a diagnostic-sampling + * data entry. The sampling function is determined by the flags in the perf + * event hardware structure. The function always works with a combined-sampling + * data entry but ignores the the diagnostic portion if it is not available. + * + * Note that the implementation focuses on basic-sampling data entries and, if + * such an entry is not valid, the entire combined-sampling data entry is + * ignored. + * + * The overflow variables counts the number of samples that has been discarded + * due to a perf event overflow. + */ +static void hw_collect_samples(struct perf_event *event, unsigned long *sdbt, + unsigned long long *overflow) +{ + struct hws_trailer_entry *te; + struct hws_basic_entry *sample; + + te = (struct hws_trailer_entry *) trailer_entry_ptr(*sdbt); + sample = (struct hws_basic_entry *) *sdbt; + while ((unsigned long *) sample < (unsigned long *) te) { + /* Check for an empty sample */ + if (!sample->def) + break; + + /* Update perf event period */ + perf_event_count_update(event, SAMPL_RATE(&event->hw)); + + /* Check whether sample is valid */ + if (sample->def == 0x0001) { + /* If an event overflow occurred, the PMU is stopped to + * throttle event delivery. Remaining sample data is + * discarded. + */ + if (!*overflow) { + /* Check whether sample is consistent */ + if (sample->I == 0 && sample->W == 0) { + /* Deliver sample data to perf */ + *overflow = perf_push_sample(event, + sample); + } + } else + /* Count discarded samples */ + *overflow += 1; + } else { + debug_sample_entry(sample, te); + /* Sample slot is not yet written or other record. + * + * This condition can occur if the buffer was reused + * from a combined basic- and diagnostic-sampling. + * If only basic-sampling is then active, entries are + * written into the larger diagnostic entries. + * This is typically the case for sample-data-blocks + * that are not full. Stop processing if the first + * invalid format was detected. + */ + if (!te->f) + break; + } + + /* Reset sample slot and advance to next sample */ + sample->def = 0; + sample++; + } +} + +/* hw_perf_event_update() - Process sampling buffer + * @event: The perf event + * @flush_all: Flag to also flush partially filled sample-data-blocks + * + * Processes the sampling buffer and create perf event samples. + * The sampling buffer position are retrieved and saved in the TEAR_REG + * register of the specified perf event. + * + * Only full sample-data-blocks are processed. Specify the flash_all flag + * to also walk through partially filled sample-data-blocks. It is ignored + * if PERF_CPUM_SF_FULL_BLOCKS is set. The PERF_CPUM_SF_FULL_BLOCKS flag + * enforces the processing of full sample-data-blocks only (trailer entries + * with the block-full-indicator bit set). + */ +static void hw_perf_event_update(struct perf_event *event, int flush_all) +{ + struct hw_perf_event *hwc = &event->hw; + struct hws_trailer_entry *te; + unsigned long *sdbt; + unsigned long long event_overflow, sampl_overflow, num_sdb, te_flags; + int done; + + /* + * AUX buffer is used when in diagnostic sampling mode. + * No perf events/samples are created. + */ + if (SAMPL_DIAG_MODE(&event->hw)) + return; + + if (flush_all && SDB_FULL_BLOCKS(hwc)) + flush_all = 0; + + sdbt = (unsigned long *) TEAR_REG(hwc); + done = event_overflow = sampl_overflow = num_sdb = 0; + while (!done) { + /* Get the trailer entry of the sample-data-block */ + te = (struct hws_trailer_entry *) trailer_entry_ptr(*sdbt); + + /* Leave loop if no more work to do (block full indicator) */ + if (!te->f) { + done = 1; + if (!flush_all) + break; + } + + /* Check the sample overflow count */ + if (te->overflow) + /* Account sample overflows and, if a particular limit + * is reached, extend the sampling buffer. + * For details, see sfb_account_overflows(). + */ + sampl_overflow += te->overflow; + + /* Timestamps are valid for full sample-data-blocks only */ + debug_sprintf_event(sfdbg, 6, "hw_perf_event_update: sdbt=%p " + "overflow=%llu timestamp=0x%llx\n", + sdbt, te->overflow, + (te->f) ? trailer_timestamp(te) : 0ULL); + + /* Collect all samples from a single sample-data-block and + * flag if an (perf) event overflow happened. If so, the PMU + * is stopped and remaining samples will be discarded. + */ + hw_collect_samples(event, sdbt, &event_overflow); + num_sdb++; + + /* Reset trailer (using compare-double-and-swap) */ + do { + te_flags = te->flags & ~SDB_TE_BUFFER_FULL_MASK; + te_flags |= SDB_TE_ALERT_REQ_MASK; + } while (!cmpxchg_double(&te->flags, &te->overflow, + te->flags, te->overflow, + te_flags, 0ULL)); + + /* Advance to next sample-data-block */ + sdbt++; + if (is_link_entry(sdbt)) + sdbt = get_next_sdbt(sdbt); + + /* Update event hardware registers */ + TEAR_REG(hwc) = (unsigned long) sdbt; + + /* Stop processing sample-data if all samples of the current + * sample-data-block were flushed even if it was not full. + */ + if (flush_all && done) + break; + } + + /* Account sample overflows in the event hardware structure */ + if (sampl_overflow) + OVERFLOW_REG(hwc) = DIV_ROUND_UP(OVERFLOW_REG(hwc) + + sampl_overflow, 1 + num_sdb); + + /* Perf_event_overflow() and perf_event_account_interrupt() limit + * the interrupt rate to an upper limit. Roughly 1000 samples per + * task tick. + * Hitting this limit results in a large number + * of throttled REF_REPORT_THROTTLE entries and the samples + * are dropped. + * Slightly increase the interval to avoid hitting this limit. + */ + if (event_overflow) { + SAMPL_RATE(hwc) += DIV_ROUND_UP(SAMPL_RATE(hwc), 10); + debug_sprintf_event(sfdbg, 1, "%s: rate adjustment %ld\n", + __func__, + DIV_ROUND_UP(SAMPL_RATE(hwc), 10)); + } + + if (sampl_overflow || event_overflow) + debug_sprintf_event(sfdbg, 4, "hw_perf_event_update: " + "overflow stats: sample=%llu event=%llu\n", + sampl_overflow, event_overflow); +} + +#define AUX_SDB_INDEX(aux, i) ((i) % aux->sfb.num_sdb) +#define AUX_SDB_NUM(aux, start, end) (end >= start ? end - start + 1 : 0) +#define AUX_SDB_NUM_ALERT(aux) AUX_SDB_NUM(aux, aux->head, aux->alert_mark) +#define AUX_SDB_NUM_EMPTY(aux) AUX_SDB_NUM(aux, aux->head, aux->empty_mark) + +/* + * Get trailer entry by index of SDB. + */ +static struct hws_trailer_entry *aux_sdb_trailer(struct aux_buffer *aux, + unsigned long index) +{ + unsigned long sdb; + + index = AUX_SDB_INDEX(aux, index); + sdb = aux->sdb_index[index]; + return (struct hws_trailer_entry *)trailer_entry_ptr(sdb); +} + +/* + * Finish sampling on the cpu. Called by cpumsf_pmu_del() with pmu + * disabled. Collect the full SDBs in AUX buffer which have not reached + * the point of alert indicator. And ignore the SDBs which are not + * full. + * + * 1. Scan SDBs to see how much data is there and consume them. + * 2. Remove alert indicator in the buffer. + */ +static void aux_output_end(struct perf_output_handle *handle) +{ + unsigned long i, range_scan, idx; + struct aux_buffer *aux; + struct hws_trailer_entry *te; + + aux = perf_get_aux(handle); + if (!aux) + return; + + range_scan = AUX_SDB_NUM_ALERT(aux); + for (i = 0, idx = aux->head; i < range_scan; i++, idx++) { + te = aux_sdb_trailer(aux, idx); + if (!(te->flags & SDB_TE_BUFFER_FULL_MASK)) + break; + } + /* i is num of SDBs which are full */ + perf_aux_output_end(handle, i << PAGE_SHIFT); + + /* Remove alert indicators in the buffer */ + te = aux_sdb_trailer(aux, aux->alert_mark); + te->flags &= ~SDB_TE_ALERT_REQ_MASK; + + debug_sprintf_event(sfdbg, 6, "aux_output_end: collect %lx SDBs\n", i); +} + +/* + * Start sampling on the CPU. Called by cpumsf_pmu_add() when an event + * is first added to the CPU or rescheduled again to the CPU. It is called + * with pmu disabled. + * + * 1. Reset the trailer of SDBs to get ready for new data. + * 2. Tell the hardware where to put the data by reset the SDBs buffer + * head(tear/dear). + */ +static int aux_output_begin(struct perf_output_handle *handle, + struct aux_buffer *aux, + struct cpu_hw_sf *cpuhw) +{ + unsigned long range; + unsigned long i, range_scan, idx; + unsigned long head, base, offset; + struct hws_trailer_entry *te; + + if (WARN_ON_ONCE(handle->head & ~PAGE_MASK)) + return -EINVAL; + + aux->head = handle->head >> PAGE_SHIFT; + range = (handle->size + 1) >> PAGE_SHIFT; + if (range <= 1) + return -ENOMEM; + + /* + * SDBs between aux->head and aux->empty_mark are already ready + * for new data. range_scan is num of SDBs not within them. + */ + if (range > AUX_SDB_NUM_EMPTY(aux)) { + range_scan = range - AUX_SDB_NUM_EMPTY(aux); + idx = aux->empty_mark + 1; + for (i = 0; i < range_scan; i++, idx++) { + te = aux_sdb_trailer(aux, idx); + te->flags &= ~(SDB_TE_BUFFER_FULL_MASK | + SDB_TE_ALERT_REQ_MASK); + te->overflow = 0; + } + /* Save the position of empty SDBs */ + aux->empty_mark = aux->head + range - 1; + } + + /* Set alert indicator */ + aux->alert_mark = aux->head + range/2 - 1; + te = aux_sdb_trailer(aux, aux->alert_mark); + te->flags = te->flags | SDB_TE_ALERT_REQ_MASK; + + /* Reset hardware buffer head */ + head = AUX_SDB_INDEX(aux, aux->head); + base = aux->sdbt_index[head / CPUM_SF_SDB_PER_TABLE]; + offset = head % CPUM_SF_SDB_PER_TABLE; + cpuhw->lsctl.tear = base + offset * sizeof(unsigned long); + cpuhw->lsctl.dear = aux->sdb_index[head]; + + debug_sprintf_event(sfdbg, 6, "aux_output_begin: " + "head->alert_mark->empty_mark (num_alert, range)" + "[%lx -> %lx -> %lx] (%lx, %lx) " + "tear index %lx, tear %lx dear %lx\n", + aux->head, aux->alert_mark, aux->empty_mark, + AUX_SDB_NUM_ALERT(aux), range, + head / CPUM_SF_SDB_PER_TABLE, + cpuhw->lsctl.tear, + cpuhw->lsctl.dear); + + return 0; +} + +/* + * Set alert indicator on SDB at index @alert_index while sampler is running. + * + * Return true if successfully. + * Return false if full indicator is already set by hardware sampler. + */ +static bool aux_set_alert(struct aux_buffer *aux, unsigned long alert_index, + unsigned long long *overflow) +{ + unsigned long long orig_overflow, orig_flags, new_flags; + struct hws_trailer_entry *te; + + te = aux_sdb_trailer(aux, alert_index); + do { + orig_flags = te->flags; + *overflow = orig_overflow = te->overflow; + if (orig_flags & SDB_TE_BUFFER_FULL_MASK) { + /* + * SDB is already set by hardware. + * Abort and try to set somewhere + * behind. + */ + return false; + } + new_flags = orig_flags | SDB_TE_ALERT_REQ_MASK; + } while (!cmpxchg_double(&te->flags, &te->overflow, + orig_flags, orig_overflow, + new_flags, 0ULL)); + return true; +} + +/* + * aux_reset_buffer() - Scan and setup SDBs for new samples + * @aux: The AUX buffer to set + * @range: The range of SDBs to scan started from aux->head + * @overflow: Set to overflow count + * + * Set alert indicator on the SDB at index of aux->alert_mark. If this SDB is + * marked as empty, check if it is already set full by the hardware sampler. + * If yes, that means new data is already there before we can set an alert + * indicator. Caller should try to set alert indicator to some position behind. + * + * Scan the SDBs in AUX buffer from behind aux->empty_mark. They are used + * previously and have already been consumed by user space. Reset these SDBs + * (clear full indicator and alert indicator) for new data. + * If aux->alert_mark fall in this area, just set it. Overflow count is + * recorded while scanning. + * + * SDBs between aux->head and aux->empty_mark are already reset at last time. + * and ready for new samples. So scanning on this area could be skipped. + * + * Return true if alert indicator is set successfully and false if not. + */ +static bool aux_reset_buffer(struct aux_buffer *aux, unsigned long range, + unsigned long long *overflow) +{ + unsigned long long orig_overflow, orig_flags, new_flags; + unsigned long i, range_scan, idx; + struct hws_trailer_entry *te; + + if (range <= AUX_SDB_NUM_EMPTY(aux)) + /* + * No need to scan. All SDBs in range are marked as empty. + * Just set alert indicator. Should check race with hardware + * sampler. + */ + return aux_set_alert(aux, aux->alert_mark, overflow); + + if (aux->alert_mark <= aux->empty_mark) + /* + * Set alert indicator on empty SDB. Should check race + * with hardware sampler. + */ + if (!aux_set_alert(aux, aux->alert_mark, overflow)) + return false; + + /* + * Scan the SDBs to clear full and alert indicator used previously. + * Start scanning from one SDB behind empty_mark. If the new alert + * indicator fall into this range, set it. + */ + range_scan = range - AUX_SDB_NUM_EMPTY(aux); + idx = aux->empty_mark + 1; + for (i = 0; i < range_scan; i++, idx++) { + te = aux_sdb_trailer(aux, idx); + do { + orig_flags = te->flags; + orig_overflow = te->overflow; + new_flags = orig_flags & ~SDB_TE_BUFFER_FULL_MASK; + if (idx == aux->alert_mark) + new_flags |= SDB_TE_ALERT_REQ_MASK; + else + new_flags &= ~SDB_TE_ALERT_REQ_MASK; + } while (!cmpxchg_double(&te->flags, &te->overflow, + orig_flags, orig_overflow, + new_flags, 0ULL)); + *overflow += orig_overflow; + } + + /* Update empty_mark to new position */ + aux->empty_mark = aux->head + range - 1; + + return true; +} + +/* + * Measurement alert handler for diagnostic mode sampling. + */ +static void hw_collect_aux(struct cpu_hw_sf *cpuhw) +{ + struct aux_buffer *aux; + int done = 0; + unsigned long range = 0, size; + unsigned long long overflow = 0; + struct perf_output_handle *handle = &cpuhw->handle; + unsigned long num_sdb; + + aux = perf_get_aux(handle); + if (WARN_ON_ONCE(!aux)) + return; + + /* Inform user space new data arrived */ + size = AUX_SDB_NUM_ALERT(aux) << PAGE_SHIFT; + perf_aux_output_end(handle, size); + num_sdb = aux->sfb.num_sdb; + + num_sdb = aux->sfb.num_sdb; + while (!done) { + /* Get an output handle */ + aux = perf_aux_output_begin(handle, cpuhw->event); + if (handle->size == 0) { + pr_err("The AUX buffer with %lu pages for the " + "diagnostic-sampling mode is full\n", + num_sdb); + debug_sprintf_event(sfdbg, 1, "AUX buffer used up\n"); + break; + } + if (WARN_ON_ONCE(!aux)) + return; + + /* Update head and alert_mark to new position */ + aux->head = handle->head >> PAGE_SHIFT; + range = (handle->size + 1) >> PAGE_SHIFT; + if (range == 1) + aux->alert_mark = aux->head; + else + aux->alert_mark = aux->head + range/2 - 1; + + if (aux_reset_buffer(aux, range, &overflow)) { + if (!overflow) { + done = 1; + break; + } + size = range << PAGE_SHIFT; + perf_aux_output_end(&cpuhw->handle, size); + pr_err("Sample data caused the AUX buffer with %lu " + "pages to overflow\n", num_sdb); + debug_sprintf_event(sfdbg, 1, "head %lx range %lx " + "overflow %llx\n", + aux->head, range, overflow); + } else { + size = AUX_SDB_NUM_ALERT(aux) << PAGE_SHIFT; + perf_aux_output_end(&cpuhw->handle, size); + debug_sprintf_event(sfdbg, 6, "head %lx alert %lx " + "already full, try another\n", + aux->head, aux->alert_mark); + } + } + + if (done) + debug_sprintf_event(sfdbg, 6, "aux_reset_buffer: " + "[%lx -> %lx -> %lx] (%lx, %lx)\n", + aux->head, aux->alert_mark, aux->empty_mark, + AUX_SDB_NUM_ALERT(aux), range); +} + +/* + * Callback when freeing AUX buffers. + */ +static void aux_buffer_free(void *data) +{ + struct aux_buffer *aux = data; + unsigned long i, num_sdbt; + + if (!aux) + return; + + /* Free SDBT. SDB is freed by the caller */ + num_sdbt = aux->sfb.num_sdbt; + for (i = 0; i < num_sdbt; i++) + free_page(aux->sdbt_index[i]); + + kfree(aux->sdbt_index); + kfree(aux->sdb_index); + kfree(aux); + + debug_sprintf_event(sfdbg, 4, "aux_buffer_free: free " + "%lu SDBTs\n", num_sdbt); +} + +static void aux_sdb_init(unsigned long sdb) +{ + struct hws_trailer_entry *te; + + te = (struct hws_trailer_entry *)trailer_entry_ptr(sdb); + + /* Save clock base */ + te->clock_base = 1; + memcpy(&te->progusage2, &tod_clock_base[1], 8); +} + +/* + * aux_buffer_setup() - Setup AUX buffer for diagnostic mode sampling + * @event: Event the buffer is setup for, event->cpu == -1 means current + * @pages: Array of pointers to buffer pages passed from perf core + * @nr_pages: Total pages + * @snapshot: Flag for snapshot mode + * + * This is the callback when setup an event using AUX buffer. Perf tool can + * trigger this by an additional mmap() call on the event. Unlike the buffer + * for basic samples, AUX buffer belongs to the event. It is scheduled with + * the task among online cpus when it is a per-thread event. + * + * Return the private AUX buffer structure if success or NULL if fails. + */ +static void *aux_buffer_setup(struct perf_event *event, void **pages, + int nr_pages, bool snapshot) +{ + struct sf_buffer *sfb; + struct aux_buffer *aux; + unsigned long *new, *tail; + int i, n_sdbt; + + if (!nr_pages || !pages) + return NULL; + + if (nr_pages > CPUM_SF_MAX_SDB * CPUM_SF_SDB_DIAG_FACTOR) { + pr_err("AUX buffer size (%i pages) is larger than the " + "maximum sampling buffer limit\n", + nr_pages); + return NULL; + } else if (nr_pages < CPUM_SF_MIN_SDB * CPUM_SF_SDB_DIAG_FACTOR) { + pr_err("AUX buffer size (%i pages) is less than the " + "minimum sampling buffer limit\n", + nr_pages); + return NULL; + } + + /* Allocate aux_buffer struct for the event */ + aux = kzalloc(sizeof(struct aux_buffer), GFP_KERNEL); + if (!aux) + goto no_aux; + sfb = &aux->sfb; + + /* Allocate sdbt_index for fast reference */ + n_sdbt = (nr_pages + CPUM_SF_SDB_PER_TABLE - 1) / CPUM_SF_SDB_PER_TABLE; + aux->sdbt_index = kmalloc_array(n_sdbt, sizeof(void *), GFP_KERNEL); + if (!aux->sdbt_index) + goto no_sdbt_index; + + /* Allocate sdb_index for fast reference */ + aux->sdb_index = kmalloc_array(nr_pages, sizeof(void *), GFP_KERNEL); + if (!aux->sdb_index) + goto no_sdb_index; + + /* Allocate the first SDBT */ + sfb->num_sdbt = 0; + sfb->sdbt = (unsigned long *) get_zeroed_page(GFP_KERNEL); + if (!sfb->sdbt) + goto no_sdbt; + aux->sdbt_index[sfb->num_sdbt++] = (unsigned long)sfb->sdbt; + tail = sfb->tail = sfb->sdbt; + + /* + * Link the provided pages of AUX buffer to SDBT. + * Allocate SDBT if needed. + */ + for (i = 0; i < nr_pages; i++, tail++) { + if (require_table_link(tail)) { + new = (unsigned long *) get_zeroed_page(GFP_KERNEL); + if (!new) + goto no_sdbt; + aux->sdbt_index[sfb->num_sdbt++] = (unsigned long)new; + /* Link current page to tail of chain */ + *tail = (unsigned long)(void *) new + 1; + tail = new; + } + /* Tail is the entry in a SDBT */ + *tail = (unsigned long)pages[i]; + aux->sdb_index[i] = (unsigned long)pages[i]; + aux_sdb_init((unsigned long)pages[i]); + } + sfb->num_sdb = nr_pages; + + /* Link the last entry in the SDBT to the first SDBT */ + *tail = (unsigned long) sfb->sdbt + 1; + sfb->tail = tail; + + /* + * Initial all SDBs are zeroed. Mark it as empty. + * So there is no need to clear the full indicator + * when this event is first added. + */ + aux->empty_mark = sfb->num_sdb - 1; + + debug_sprintf_event(sfdbg, 4, "aux_buffer_setup: setup %lu SDBTs" + " and %lu SDBs\n", + sfb->num_sdbt, sfb->num_sdb); + + return aux; + +no_sdbt: + /* SDBs (AUX buffer pages) are freed by caller */ + for (i = 0; i < sfb->num_sdbt; i++) + free_page(aux->sdbt_index[i]); + kfree(aux->sdb_index); +no_sdb_index: + kfree(aux->sdbt_index); +no_sdbt_index: + kfree(aux); +no_aux: + return NULL; +} + +static void cpumsf_pmu_read(struct perf_event *event) +{ + /* Nothing to do ... updates are interrupt-driven */ +} + +/* Activate sampling control. + * Next call of pmu_enable() starts sampling. + */ +static void cpumsf_pmu_start(struct perf_event *event, int flags) +{ + struct cpu_hw_sf *cpuhw = this_cpu_ptr(&cpu_hw_sf); + + if (WARN_ON_ONCE(!(event->hw.state & PERF_HES_STOPPED))) + return; + + if (flags & PERF_EF_RELOAD) + WARN_ON_ONCE(!(event->hw.state & PERF_HES_UPTODATE)); + + perf_pmu_disable(event->pmu); + event->hw.state = 0; + cpuhw->lsctl.cs = 1; + if (SAMPL_DIAG_MODE(&event->hw)) + cpuhw->lsctl.cd = 1; + perf_pmu_enable(event->pmu); +} + +/* Deactivate sampling control. + * Next call of pmu_enable() stops sampling. + */ +static void cpumsf_pmu_stop(struct perf_event *event, int flags) +{ + struct cpu_hw_sf *cpuhw = this_cpu_ptr(&cpu_hw_sf); + + if (event->hw.state & PERF_HES_STOPPED) + return; + + perf_pmu_disable(event->pmu); + cpuhw->lsctl.cs = 0; + cpuhw->lsctl.cd = 0; + event->hw.state |= PERF_HES_STOPPED; + + if ((flags & PERF_EF_UPDATE) && !(event->hw.state & PERF_HES_UPTODATE)) { + hw_perf_event_update(event, 1); + event->hw.state |= PERF_HES_UPTODATE; + } + perf_pmu_enable(event->pmu); +} + +static int cpumsf_pmu_add(struct perf_event *event, int flags) +{ + struct cpu_hw_sf *cpuhw = this_cpu_ptr(&cpu_hw_sf); + struct aux_buffer *aux; + int err; + + if (cpuhw->flags & PMU_F_IN_USE) + return -EAGAIN; + + if (!SAMPL_DIAG_MODE(&event->hw) && !cpuhw->sfb.sdbt) + return -EINVAL; + + err = 0; + perf_pmu_disable(event->pmu); + + event->hw.state = PERF_HES_UPTODATE | PERF_HES_STOPPED; + + /* Set up sampling controls. Always program the sampling register + * using the SDB-table start. Reset TEAR_REG event hardware register + * that is used by hw_perf_event_update() to store the sampling buffer + * position after samples have been flushed. + */ + cpuhw->lsctl.s = 0; + cpuhw->lsctl.h = 1; + cpuhw->lsctl.interval = SAMPL_RATE(&event->hw); + if (!SAMPL_DIAG_MODE(&event->hw)) { + cpuhw->lsctl.tear = (unsigned long) cpuhw->sfb.sdbt; + cpuhw->lsctl.dear = *(unsigned long *) cpuhw->sfb.sdbt; + hw_reset_registers(&event->hw, cpuhw->sfb.sdbt); + } + + /* Ensure sampling functions are in the disabled state. If disabled, + * switch on sampling enable control. */ + if (WARN_ON_ONCE(cpuhw->lsctl.es == 1 || cpuhw->lsctl.ed == 1)) { + err = -EAGAIN; + goto out; + } + if (SAMPL_DIAG_MODE(&event->hw)) { + aux = perf_aux_output_begin(&cpuhw->handle, event); + if (!aux) { + err = -EINVAL; + goto out; + } + err = aux_output_begin(&cpuhw->handle, aux, cpuhw); + if (err) + goto out; + cpuhw->lsctl.ed = 1; + } + cpuhw->lsctl.es = 1; + + /* Set in_use flag and store event */ + cpuhw->event = event; + cpuhw->flags |= PMU_F_IN_USE; + + if (flags & PERF_EF_START) + cpumsf_pmu_start(event, PERF_EF_RELOAD); +out: + perf_event_update_userpage(event); + perf_pmu_enable(event->pmu); + return err; +} + +static void cpumsf_pmu_del(struct perf_event *event, int flags) +{ + struct cpu_hw_sf *cpuhw = this_cpu_ptr(&cpu_hw_sf); + + perf_pmu_disable(event->pmu); + cpumsf_pmu_stop(event, PERF_EF_UPDATE); + + cpuhw->lsctl.es = 0; + cpuhw->lsctl.ed = 0; + cpuhw->flags &= ~PMU_F_IN_USE; + cpuhw->event = NULL; + + if (SAMPL_DIAG_MODE(&event->hw)) + aux_output_end(&cpuhw->handle); + perf_event_update_userpage(event); + perf_pmu_enable(event->pmu); +} + +CPUMF_EVENT_ATTR(SF, SF_CYCLES_BASIC, PERF_EVENT_CPUM_SF); +CPUMF_EVENT_ATTR(SF, SF_CYCLES_BASIC_DIAG, PERF_EVENT_CPUM_SF_DIAG); + +static struct attribute *cpumsf_pmu_events_attr[] = { + CPUMF_EVENT_PTR(SF, SF_CYCLES_BASIC), + NULL, + NULL, +}; + +PMU_FORMAT_ATTR(event, "config:0-63"); + +static struct attribute *cpumsf_pmu_format_attr[] = { + &format_attr_event.attr, + NULL, +}; + +static struct attribute_group cpumsf_pmu_events_group = { + .name = "events", + .attrs = cpumsf_pmu_events_attr, +}; +static struct attribute_group cpumsf_pmu_format_group = { + .name = "format", + .attrs = cpumsf_pmu_format_attr, +}; +static const struct attribute_group *cpumsf_pmu_attr_groups[] = { + &cpumsf_pmu_events_group, + &cpumsf_pmu_format_group, + NULL, +}; + +static struct pmu cpumf_sampling = { + .pmu_enable = cpumsf_pmu_enable, + .pmu_disable = cpumsf_pmu_disable, + + .event_init = cpumsf_pmu_event_init, + .add = cpumsf_pmu_add, + .del = cpumsf_pmu_del, + + .start = cpumsf_pmu_start, + .stop = cpumsf_pmu_stop, + .read = cpumsf_pmu_read, + + .attr_groups = cpumsf_pmu_attr_groups, + + .setup_aux = aux_buffer_setup, + .free_aux = aux_buffer_free, +}; + +static void cpumf_measurement_alert(struct ext_code ext_code, + unsigned int alert, unsigned long unused) +{ + struct cpu_hw_sf *cpuhw; + + if (!(alert & CPU_MF_INT_SF_MASK)) + return; + inc_irq_stat(IRQEXT_CMS); + cpuhw = this_cpu_ptr(&cpu_hw_sf); + + /* Measurement alerts are shared and might happen when the PMU + * is not reserved. Ignore these alerts in this case. */ + if (!(cpuhw->flags & PMU_F_RESERVED)) + return; + + /* The processing below must take care of multiple alert events that + * might be indicated concurrently. */ + + /* Program alert request */ + if (alert & CPU_MF_INT_SF_PRA) { + if (cpuhw->flags & PMU_F_IN_USE) + if (SAMPL_DIAG_MODE(&cpuhw->event->hw)) + hw_collect_aux(cpuhw); + else + hw_perf_event_update(cpuhw->event, 0); + else + WARN_ON_ONCE(!(cpuhw->flags & PMU_F_IN_USE)); + } + + /* Report measurement alerts only for non-PRA codes */ + if (alert != CPU_MF_INT_SF_PRA) + debug_sprintf_event(sfdbg, 6, "measurement alert: 0x%x\n", alert); + + /* Sampling authorization change request */ + if (alert & CPU_MF_INT_SF_SACA) + qsi(&cpuhw->qsi); + + /* Loss of sample data due to high-priority machine activities */ + if (alert & CPU_MF_INT_SF_LSDA) { + pr_err("Sample data was lost\n"); + cpuhw->flags |= PMU_F_ERR_LSDA; + sf_disable(); + } + + /* Invalid sampling buffer entry */ + if (alert & (CPU_MF_INT_SF_IAE|CPU_MF_INT_SF_ISE)) { + pr_err("A sampling buffer entry is incorrect (alert=0x%x)\n", + alert); + cpuhw->flags |= PMU_F_ERR_IBE; + sf_disable(); + } +} +static int cpusf_pmu_setup(unsigned int cpu, int flags) +{ + /* Ignore the notification if no events are scheduled on the PMU. + * This might be racy... + */ + if (!atomic_read(&num_events)) + return 0; + + local_irq_disable(); + setup_pmc_cpu(&flags); + local_irq_enable(); + return 0; +} + +static int s390_pmu_sf_online_cpu(unsigned int cpu) +{ + return cpusf_pmu_setup(cpu, PMC_INIT); +} + +static int s390_pmu_sf_offline_cpu(unsigned int cpu) +{ + return cpusf_pmu_setup(cpu, PMC_RELEASE); +} + +static int param_get_sfb_size(char *buffer, const struct kernel_param *kp) +{ + if (!cpum_sf_avail()) + return -ENODEV; + return sprintf(buffer, "%lu,%lu", CPUM_SF_MIN_SDB, CPUM_SF_MAX_SDB); +} + +static int param_set_sfb_size(const char *val, const struct kernel_param *kp) +{ + int rc; + unsigned long min, max; + + if (!cpum_sf_avail()) + return -ENODEV; + if (!val || !strlen(val)) + return -EINVAL; + + /* Valid parameter values: "min,max" or "max" */ + min = CPUM_SF_MIN_SDB; + max = CPUM_SF_MAX_SDB; + if (strchr(val, ',')) + rc = (sscanf(val, "%lu,%lu", &min, &max) == 2) ? 0 : -EINVAL; + else + rc = kstrtoul(val, 10, &max); + + if (min < 2 || min >= max || max > get_num_physpages()) + rc = -EINVAL; + if (rc) + return rc; + + sfb_set_limits(min, max); + pr_info("The sampling buffer limits have changed to: " + "min=%lu max=%lu (diag=x%lu)\n", + CPUM_SF_MIN_SDB, CPUM_SF_MAX_SDB, CPUM_SF_SDB_DIAG_FACTOR); + return 0; +} + +#define param_check_sfb_size(name, p) __param_check(name, p, void) +static const struct kernel_param_ops param_ops_sfb_size = { + .set = param_set_sfb_size, + .get = param_get_sfb_size, +}; + +#define RS_INIT_FAILURE_QSI 0x0001 +#define RS_INIT_FAILURE_BSDES 0x0002 +#define RS_INIT_FAILURE_ALRT 0x0003 +#define RS_INIT_FAILURE_PERF 0x0004 +static void __init pr_cpumsf_err(unsigned int reason) +{ + pr_err("Sampling facility support for perf is not available: " + "reason=%04x\n", reason); +} + +static int __init init_cpum_sampling_pmu(void) +{ + struct hws_qsi_info_block si; + int err; + + if (!cpum_sf_avail()) + return -ENODEV; + + memset(&si, 0, sizeof(si)); + if (qsi(&si)) { + pr_cpumsf_err(RS_INIT_FAILURE_QSI); + return -ENODEV; + } + + if (!si.as && !si.ad) + return -ENODEV; + + if (si.bsdes != sizeof(struct hws_basic_entry)) { + pr_cpumsf_err(RS_INIT_FAILURE_BSDES); + return -EINVAL; + } + + if (si.ad) { + sfb_set_limits(CPUM_SF_MIN_SDB, CPUM_SF_MAX_SDB); + cpumsf_pmu_events_attr[1] = + CPUMF_EVENT_PTR(SF, SF_CYCLES_BASIC_DIAG); + } + + sfdbg = debug_register(KMSG_COMPONENT, 2, 1, 80); + if (!sfdbg) { + pr_err("Registering for s390dbf failed\n"); + return -ENOMEM; + } + debug_register_view(sfdbg, &debug_sprintf_view); + + err = register_external_irq(EXT_IRQ_MEASURE_ALERT, + cpumf_measurement_alert); + if (err) { + pr_cpumsf_err(RS_INIT_FAILURE_ALRT); + debug_unregister(sfdbg); + goto out; + } + + err = perf_pmu_register(&cpumf_sampling, "cpum_sf", PERF_TYPE_RAW); + if (err) { + pr_cpumsf_err(RS_INIT_FAILURE_PERF); + unregister_external_irq(EXT_IRQ_MEASURE_ALERT, + cpumf_measurement_alert); + debug_unregister(sfdbg); + goto out; + } + + cpuhp_setup_state(CPUHP_AP_PERF_S390_SF_ONLINE, "perf/s390/sf:online", + s390_pmu_sf_online_cpu, s390_pmu_sf_offline_cpu); +out: + return err; +} +arch_initcall(init_cpum_sampling_pmu); +core_param(cpum_sfb_size, CPUM_SF_MAX_SDB, sfb_size, 0644); |