Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...

[GitHub/mt8127/android_kernel_alcatel_ttab.git] / arch / x86 / kernel / cpu / perf_event_intel_ds.c

#include <linux/bitops.h>
#include <linux/types.h>
#include <linux/slab.h>

#include <asm/perf_event.h>
#include <asm/insn.h>

#include "perf_event.h"

/* The size of a BTS record in bytes: */
#define BTS_RECORD_SIZE         24

#define BTS_BUFFER_SIZE         (PAGE_SIZE << 4)
#define PEBS_BUFFER_SIZE        PAGE_SIZE

/*
 * pebs_record_32 for p4 and core not supported

struct pebs_record_32 {
        u32 flags, ip;
        u32 ax, bc, cx, dx;
        u32 si, di, bp, sp;
};

 */

struct pebs_record_core {
        u64 flags, ip;
        u64 ax, bx, cx, dx;
        u64 si, di, bp, sp;
        u64 r8,  r9,  r10, r11;
        u64 r12, r13, r14, r15;
};

struct pebs_record_nhm {
        u64 flags, ip;
        u64 ax, bx, cx, dx;
        u64 si, di, bp, sp;
        u64 r8,  r9,  r10, r11;
        u64 r12, r13, r14, r15;
        u64 status, dla, dse, lat;
};

void init_debug_store_on_cpu(int cpu)
{
        struct debug_store *ds = per_cpu(cpu_hw_events, cpu).ds;

        if (!ds)
                return;

        wrmsr_on_cpu(cpu, MSR_IA32_DS_AREA,
                     (u32)((u64)(unsigned long)ds),
                     (u32)((u64)(unsigned long)ds >> 32));
}

void fini_debug_store_on_cpu(int cpu)
{
        if (!per_cpu(cpu_hw_events, cpu).ds)
                return;

        wrmsr_on_cpu(cpu, MSR_IA32_DS_AREA, 0, 0);
}

static int alloc_pebs_buffer(int cpu)
{
        struct debug_store *ds = per_cpu(cpu_hw_events, cpu).ds;
        int node = cpu_to_node(cpu);
        int max, thresh = 1; /* always use a single PEBS record */
        void *buffer;

        if (!x86_pmu.pebs)
                return 0;

        buffer = kmalloc_node(PEBS_BUFFER_SIZE, GFP_KERNEL | __GFP_ZERO, node);
        if (unlikely(!buffer))
                return -ENOMEM;

        max = PEBS_BUFFER_SIZE / x86_pmu.pebs_record_size;

        ds->pebs_buffer_base = (u64)(unsigned long)buffer;
        ds->pebs_index = ds->pebs_buffer_base;
        ds->pebs_absolute_maximum = ds->pebs_buffer_base +
                max * x86_pmu.pebs_record_size;

        ds->pebs_interrupt_threshold = ds->pebs_buffer_base +
                thresh * x86_pmu.pebs_record_size;

        return 0;
}

static void release_pebs_buffer(int cpu)
{
        struct debug_store *ds = per_cpu(cpu_hw_events, cpu).ds;

        if (!ds || !x86_pmu.pebs)
                return;

        kfree((void *)(unsigned long)ds->pebs_buffer_base);
        ds->pebs_buffer_base = 0;
}

static int alloc_bts_buffer(int cpu)
{
        struct debug_store *ds = per_cpu(cpu_hw_events, cpu).ds;
        int node = cpu_to_node(cpu);
        int max, thresh;
        void *buffer;

        if (!x86_pmu.bts)
                return 0;

        buffer = kmalloc_node(BTS_BUFFER_SIZE, GFP_KERNEL | __GFP_ZERO, node);
        if (unlikely(!buffer))
                return -ENOMEM;

        max = BTS_BUFFER_SIZE / BTS_RECORD_SIZE;
        thresh = max / 16;

        ds->bts_buffer_base = (u64)(unsigned long)buffer;
        ds->bts_index = ds->bts_buffer_base;
        ds->bts_absolute_maximum = ds->bts_buffer_base +
                max * BTS_RECORD_SIZE;
        ds->bts_interrupt_threshold = ds->bts_absolute_maximum -
                thresh * BTS_RECORD_SIZE;

        return 0;
}

static void release_bts_buffer(int cpu)
{
        struct debug_store *ds = per_cpu(cpu_hw_events, cpu).ds;

        if (!ds || !x86_pmu.bts)
                return;

        kfree((void *)(unsigned long)ds->bts_buffer_base);
        ds->bts_buffer_base = 0;
}

static int alloc_ds_buffer(int cpu)
{
        int node = cpu_to_node(cpu);
        struct debug_store *ds;

        ds = kmalloc_node(sizeof(*ds), GFP_KERNEL | __GFP_ZERO, node);
        if (unlikely(!ds))
                return -ENOMEM;

        per_cpu(cpu_hw_events, cpu).ds = ds;

        return 0;
}

static void release_ds_buffer(int cpu)
{
        struct debug_store *ds = per_cpu(cpu_hw_events, cpu).ds;

        if (!ds)
                return;

        per_cpu(cpu_hw_events, cpu).ds = NULL;
        kfree(ds);
}

void release_ds_buffers(void)
{
        int cpu;

        if (!x86_pmu.bts && !x86_pmu.pebs)
                return;

        get_online_cpus();
        for_each_online_cpu(cpu)
                fini_debug_store_on_cpu(cpu);

        for_each_possible_cpu(cpu) {
                release_pebs_buffer(cpu);
                release_bts_buffer(cpu);
                release_ds_buffer(cpu);
        }
        put_online_cpus();
}

void reserve_ds_buffers(void)
{
        int bts_err = 0, pebs_err = 0;
        int cpu;

        x86_pmu.bts_active = 0;
        x86_pmu.pebs_active = 0;

        if (!x86_pmu.bts && !x86_pmu.pebs)
                return;

        if (!x86_pmu.bts)
                bts_err = 1;

        if (!x86_pmu.pebs)
                pebs_err = 1;

        get_online_cpus();

        for_each_possible_cpu(cpu) {
                if (alloc_ds_buffer(cpu)) {
                        bts_err = 1;
                        pebs_err = 1;
                }

                if (!bts_err && alloc_bts_buffer(cpu))
                        bts_err = 1;

                if (!pebs_err && alloc_pebs_buffer(cpu))
                        pebs_err = 1;

                if (bts_err && pebs_err)
                        break;
        }

        if (bts_err) {
                for_each_possible_cpu(cpu)
                        release_bts_buffer(cpu);
        }

        if (pebs_err) {
                for_each_possible_cpu(cpu)
                        release_pebs_buffer(cpu);
        }

        if (bts_err && pebs_err) {
                for_each_possible_cpu(cpu)
                        release_ds_buffer(cpu);
        } else {
                if (x86_pmu.bts && !bts_err)
                        x86_pmu.bts_active = 1;

                if (x86_pmu.pebs && !pebs_err)
                        x86_pmu.pebs_active = 1;

                for_each_online_cpu(cpu)
                        init_debug_store_on_cpu(cpu);
        }

        put_online_cpus();
}

/*
 * BTS
 */

struct event_constraint bts_constraint =
        EVENT_CONSTRAINT(0, 1ULL << INTEL_PMC_IDX_FIXED_BTS, 0);

void intel_pmu_enable_bts(u64 config)
{
        unsigned long debugctlmsr;

        debugctlmsr = get_debugctlmsr();

        debugctlmsr |= DEBUGCTLMSR_TR;
        debugctlmsr |= DEBUGCTLMSR_BTS;
        debugctlmsr |= DEBUGCTLMSR_BTINT;

        if (!(config & ARCH_PERFMON_EVENTSEL_OS))
                debugctlmsr |= DEBUGCTLMSR_BTS_OFF_OS;

        if (!(config & ARCH_PERFMON_EVENTSEL_USR))
                debugctlmsr |= DEBUGCTLMSR_BTS_OFF_USR;

        update_debugctlmsr(debugctlmsr);
}

void intel_pmu_disable_bts(void)
{
        struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
        unsigned long debugctlmsr;

        if (!cpuc->ds)
                return;

        debugctlmsr = get_debugctlmsr();

        debugctlmsr &=
                ~(DEBUGCTLMSR_TR | DEBUGCTLMSR_BTS | DEBUGCTLMSR_BTINT |
                  DEBUGCTLMSR_BTS_OFF_OS | DEBUGCTLMSR_BTS_OFF_USR);

        update_debugctlmsr(debugctlmsr);
}

int intel_pmu_drain_bts_buffer(void)
{
        struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
        struct debug_store *ds = cpuc->ds;
        struct bts_record {
                u64     from;
                u64     to;
                u64     flags;
        };
        struct perf_event *event = cpuc->events[INTEL_PMC_IDX_FIXED_BTS];
        struct bts_record *at, *top;
        struct perf_output_handle handle;
        struct perf_event_header header;
        struct perf_sample_data data;
        struct pt_regs regs;

        if (!event)
                return 0;

        if (!x86_pmu.bts_active)
                return 0;

        at  = (struct bts_record *)(unsigned long)ds->bts_buffer_base;
        top = (struct bts_record *)(unsigned long)ds->bts_index;

        if (top <= at)
                return 0;

        memset(&regs, 0, sizeof(regs));

        ds->bts_index = ds->bts_buffer_base;

        perf_sample_data_init(&data, 0, event->hw.last_period);

        /*
         * Prepare a generic sample, i.e. fill in the invariant fields.
         * We will overwrite the from and to address before we output
         * the sample.
         */
        perf_prepare_sample(&header, &data, event, &regs);

        if (perf_output_begin(&handle, event, header.size * (top - at)))
                return 1;

        for (; at < top; at++) {
                data.ip         = at->from;
                data.addr       = at->to;

                perf_output_sample(&handle, &header, &data, event);
        }

        perf_output_end(&handle);

        /* There's new data available. */
        event->hw.interrupts++;
        event->pending_kill = POLL_IN;
        return 1;
}

/*
 * PEBS
 */
struct event_constraint intel_core2_pebs_event_constraints[] = {
        INTEL_UEVENT_CONSTRAINT(0x00c0, 0x1), /* INST_RETIRED.ANY */
        INTEL_UEVENT_CONSTRAINT(0xfec1, 0x1), /* X87_OPS_RETIRED.ANY */
        INTEL_UEVENT_CONSTRAINT(0x00c5, 0x1), /* BR_INST_RETIRED.MISPRED */
        INTEL_UEVENT_CONSTRAINT(0x1fc7, 0x1), /* SIMD_INST_RETURED.ANY */
        INTEL_EVENT_CONSTRAINT(0xcb, 0x1),    /* MEM_LOAD_RETIRED.* */
        EVENT_CONSTRAINT_END
};

struct event_constraint intel_atom_pebs_event_constraints[] = {
        INTEL_UEVENT_CONSTRAINT(0x00c0, 0x1), /* INST_RETIRED.ANY */
        INTEL_UEVENT_CONSTRAINT(0x00c5, 0x1), /* MISPREDICTED_BRANCH_RETIRED */
        INTEL_EVENT_CONSTRAINT(0xcb, 0x1),    /* MEM_LOAD_RETIRED.* */
        EVENT_CONSTRAINT_END
};

struct event_constraint intel_nehalem_pebs_event_constraints[] = {
        INTEL_EVENT_CONSTRAINT(0x0b, 0xf),    /* MEM_INST_RETIRED.* */
        INTEL_EVENT_CONSTRAINT(0x0f, 0xf),    /* MEM_UNCORE_RETIRED.* */
        INTEL_UEVENT_CONSTRAINT(0x010c, 0xf), /* MEM_STORE_RETIRED.DTLB_MISS */
        INTEL_EVENT_CONSTRAINT(0xc0, 0xf),    /* INST_RETIRED.ANY */
        INTEL_EVENT_CONSTRAINT(0xc2, 0xf),    /* UOPS_RETIRED.* */
        INTEL_EVENT_CONSTRAINT(0xc4, 0xf),    /* BR_INST_RETIRED.* */
        INTEL_UEVENT_CONSTRAINT(0x02c5, 0xf), /* BR_MISP_RETIRED.NEAR_CALL */
        INTEL_EVENT_CONSTRAINT(0xc7, 0xf),    /* SSEX_UOPS_RETIRED.* */
        INTEL_UEVENT_CONSTRAINT(0x20c8, 0xf), /* ITLB_MISS_RETIRED */
        INTEL_EVENT_CONSTRAINT(0xcb, 0xf),    /* MEM_LOAD_RETIRED.* */
        INTEL_EVENT_CONSTRAINT(0xf7, 0xf),    /* FP_ASSIST.* */
        EVENT_CONSTRAINT_END
};

struct event_constraint intel_westmere_pebs_event_constraints[] = {
        INTEL_EVENT_CONSTRAINT(0x0b, 0xf),    /* MEM_INST_RETIRED.* */
        INTEL_EVENT_CONSTRAINT(0x0f, 0xf),    /* MEM_UNCORE_RETIRED.* */
        INTEL_UEVENT_CONSTRAINT(0x010c, 0xf), /* MEM_STORE_RETIRED.DTLB_MISS */
        INTEL_EVENT_CONSTRAINT(0xc0, 0xf),    /* INSTR_RETIRED.* */
        INTEL_EVENT_CONSTRAINT(0xc2, 0xf),    /* UOPS_RETIRED.* */
        INTEL_EVENT_CONSTRAINT(0xc4, 0xf),    /* BR_INST_RETIRED.* */
        INTEL_EVENT_CONSTRAINT(0xc5, 0xf),    /* BR_MISP_RETIRED.* */
        INTEL_EVENT_CONSTRAINT(0xc7, 0xf),    /* SSEX_UOPS_RETIRED.* */
        INTEL_UEVENT_CONSTRAINT(0x20c8, 0xf), /* ITLB_MISS_RETIRED */
        INTEL_EVENT_CONSTRAINT(0xcb, 0xf),    /* MEM_LOAD_RETIRED.* */
        INTEL_EVENT_CONSTRAINT(0xf7, 0xf),    /* FP_ASSIST.* */
        EVENT_CONSTRAINT_END
};

struct event_constraint intel_snb_pebs_event_constraints[] = {
        INTEL_UEVENT_CONSTRAINT(0x01c0, 0x2), /* INST_RETIRED.PRECDIST */
        INTEL_UEVENT_CONSTRAINT(0x01c2, 0xf), /* UOPS_RETIRED.ALL */
        INTEL_UEVENT_CONSTRAINT(0x02c2, 0xf), /* UOPS_RETIRED.RETIRE_SLOTS */
        INTEL_EVENT_CONSTRAINT(0xc4, 0xf),    /* BR_INST_RETIRED.* */
        INTEL_EVENT_CONSTRAINT(0xc5, 0xf),    /* BR_MISP_RETIRED.* */
        INTEL_EVENT_CONSTRAINT(0xcd, 0x8),    /* MEM_TRANS_RETIRED.* */
        INTEL_EVENT_CONSTRAINT(0xd0, 0xf),    /* MEM_UOP_RETIRED.* */
        INTEL_EVENT_CONSTRAINT(0xd1, 0xf),    /* MEM_LOAD_UOPS_RETIRED.* */
        INTEL_EVENT_CONSTRAINT(0xd2, 0xf),    /* MEM_LOAD_UOPS_LLC_HIT_RETIRED.* */
        INTEL_UEVENT_CONSTRAINT(0x02d4, 0xf), /* MEM_LOAD_UOPS_MISC_RETIRED.LLC_MISS */
        EVENT_CONSTRAINT_END
};

struct event_constraint intel_ivb_pebs_event_constraints[] = {
        INTEL_UEVENT_CONSTRAINT(0x01c0, 0x2), /* INST_RETIRED.PRECDIST */
        INTEL_UEVENT_CONSTRAINT(0x01c2, 0xf), /* UOPS_RETIRED.ALL */
        INTEL_UEVENT_CONSTRAINT(0x02c2, 0xf), /* UOPS_RETIRED.RETIRE_SLOTS */
        INTEL_EVENT_CONSTRAINT(0xc4, 0xf),    /* BR_INST_RETIRED.* */
        INTEL_EVENT_CONSTRAINT(0xc5, 0xf),    /* BR_MISP_RETIRED.* */
        INTEL_EVENT_CONSTRAINT(0xcd, 0x8),    /* MEM_TRANS_RETIRED.* */
        INTEL_EVENT_CONSTRAINT(0xd0, 0xf),    /* MEM_UOP_RETIRED.* */
        INTEL_EVENT_CONSTRAINT(0xd1, 0xf),    /* MEM_LOAD_UOPS_RETIRED.* */
        INTEL_EVENT_CONSTRAINT(0xd2, 0xf),    /* MEM_LOAD_UOPS_LLC_HIT_RETIRED.* */
        INTEL_EVENT_CONSTRAINT(0xd3, 0xf),    /* MEM_LOAD_UOPS_LLC_MISS_RETIRED.* */
        EVENT_CONSTRAINT_END
};

struct event_constraint *intel_pebs_constraints(struct perf_event *event)
{
        struct event_constraint *c;

        if (!event->attr.precise_ip)
                return NULL;

        if (x86_pmu.pebs_constraints) {
                for_each_event_constraint(c, x86_pmu.pebs_constraints) {
                        if ((event->hw.config & c->cmask) == c->code)
                                return c;
                }
        }

        return &emptyconstraint;
}

void intel_pmu_pebs_enable(struct perf_event *event)
{
        struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
        struct hw_perf_event *hwc = &event->hw;

        hwc->config &= ~ARCH_PERFMON_EVENTSEL_INT;

        cpuc->pebs_enabled |= 1ULL << hwc->idx;
}

void intel_pmu_pebs_disable(struct perf_event *event)
{
        struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
        struct hw_perf_event *hwc = &event->hw;

        cpuc->pebs_enabled &= ~(1ULL << hwc->idx);
        if (cpuc->enabled)
                wrmsrl(MSR_IA32_PEBS_ENABLE, cpuc->pebs_enabled);

        hwc->config |= ARCH_PERFMON_EVENTSEL_INT;
}

void intel_pmu_pebs_enable_all(void)
{
        struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);

        if (cpuc->pebs_enabled)
                wrmsrl(MSR_IA32_PEBS_ENABLE, cpuc->pebs_enabled);
}

void intel_pmu_pebs_disable_all(void)
{
        struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);

        if (cpuc->pebs_enabled)
                wrmsrl(MSR_IA32_PEBS_ENABLE, 0);
}

static int intel_pmu_pebs_fixup_ip(struct pt_regs *regs)
{
        struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
        unsigned long from = cpuc->lbr_entries[0].from;
        unsigned long old_to, to = cpuc->lbr_entries[0].to;
        unsigned long ip = regs->ip;
        int is_64bit = 0;

        /*
         * We don't need to fixup if the PEBS assist is fault like
         */
        if (!x86_pmu.intel_cap.pebs_trap)
                return 1;

        /*
         * No LBR entry, no basic block, no rewinding
         */
        if (!cpuc->lbr_stack.nr || !from || !to)
                return 0;

        /*
         * Basic blocks should never cross user/kernel boundaries
         */
        if (kernel_ip(ip) != kernel_ip(to))
                return 0;

        /*
         * unsigned math, either ip is before the start (impossible) or
         * the basic block is larger than 1 page (sanity)
         */
        if ((ip - to) > PAGE_SIZE)
                return 0;

        /*
         * We sampled a branch insn, rewind using the LBR stack
         */
        if (ip == to) {
                set_linear_ip(regs, from);
                return 1;
        }

        do {
                struct insn insn;
                u8 buf[MAX_INSN_SIZE];
                void *kaddr;

                old_to = to;
                if (!kernel_ip(ip)) {
                        int bytes, size = MAX_INSN_SIZE;

                        bytes = copy_from_user_nmi(buf, (void __user *)to, size);
                        if (bytes != size)
                                return 0;

                        kaddr = buf;
                } else
                        kaddr = (void *)to;

#ifdef CONFIG_X86_64
                is_64bit = kernel_ip(to) || !test_thread_flag(TIF_IA32);
#endif
                insn_init(&insn, kaddr, is_64bit);
                insn_get_length(&insn);
                to += insn.length;
        } while (to < ip);

        if (to == ip) {
                set_linear_ip(regs, old_to);
                return 1;
        }

        /*
         * Even though we decoded the basic block, the instruction stream
         * never matched the given IP, either the TO or the IP got corrupted.
         */
        return 0;
}

static void __intel_pmu_pebs_event(struct perf_event *event,
                                   struct pt_regs *iregs, void *__pebs)
{
        /*
         * We cast to pebs_record_core since that is a subset of
         * both formats and we don't use the other fields in this
         * routine.
         */
        struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
        struct pebs_record_core *pebs = __pebs;
        struct perf_sample_data data;
        struct pt_regs regs;

        if (!intel_pmu_save_and_restart(event))
                return;

        perf_sample_data_init(&data, 0, event->hw.last_period);

        /*
         * We use the interrupt regs as a base because the PEBS record
         * does not contain a full regs set, specifically it seems to
         * lack segment descriptors, which get used by things like
         * user_mode().
         *
         * In the simple case fix up only the IP and BP,SP regs, for
         * PERF_SAMPLE_IP and PERF_SAMPLE_CALLCHAIN to function properly.
         * A possible PERF_SAMPLE_REGS will have to transfer all regs.
         */
        regs = *iregs;
        regs.flags = pebs->flags;
        set_linear_ip(&regs, pebs->ip);
        regs.bp = pebs->bp;
        regs.sp = pebs->sp;

        if (event->attr.precise_ip > 1 && intel_pmu_pebs_fixup_ip(&regs))
                regs.flags |= PERF_EFLAGS_EXACT;
        else
                regs.flags &= ~PERF_EFLAGS_EXACT;

        if (has_branch_stack(event))
                data.br_stack = &cpuc->lbr_stack;

        if (perf_event_overflow(event, &data, &regs))
                x86_pmu_stop(event, 0);
}

static void intel_pmu_drain_pebs_core(struct pt_regs *iregs)
{
        struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
        struct debug_store *ds = cpuc->ds;
        struct perf_event *event = cpuc->events[0]; /* PMC0 only */
        struct pebs_record_core *at, *top;
        int n;

        if (!x86_pmu.pebs_active)
                return;

        at  = (struct pebs_record_core *)(unsigned long)ds->pebs_buffer_base;
        top = (struct pebs_record_core *)(unsigned long)ds->pebs_index;

        /*
         * Whatever else happens, drain the thing
         */
        ds->pebs_index = ds->pebs_buffer_base;

        if (!test_bit(0, cpuc->active_mask))
                return;

        WARN_ON_ONCE(!event);

        if (!event->attr.precise_ip)
                return;

        n = top - at;
        if (n <= 0)
                return;

        /*
         * Should not happen, we program the threshold at 1 and do not
         * set a reset value.
         */
        WARN_ONCE(n > 1, "bad leftover pebs %d\n", n);
        at += n - 1;

        __intel_pmu_pebs_event(event, iregs, at);
}

static void intel_pmu_drain_pebs_nhm(struct pt_regs *iregs)
{
        struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
        struct debug_store *ds = cpuc->ds;
        struct pebs_record_nhm *at, *top;
        struct perf_event *event = NULL;
        u64 status = 0;
        int bit, n;

        if (!x86_pmu.pebs_active)
                return;

        at  = (struct pebs_record_nhm *)(unsigned long)ds->pebs_buffer_base;
        top = (struct pebs_record_nhm *)(unsigned long)ds->pebs_index;

        ds->pebs_index = ds->pebs_buffer_base;

        n = top - at;
        if (n <= 0)
                return;

        /*
         * Should not happen, we program the threshold at 1 and do not
         * set a reset value.
         */
        WARN_ONCE(n > x86_pmu.max_pebs_events, "Unexpected number of pebs records %d\n", n);

        for ( ; at < top; at++) {
                for_each_set_bit(bit, (unsigned long *)&at->status, x86_pmu.max_pebs_events) {
                        event = cpuc->events[bit];
                        if (!test_bit(bit, cpuc->active_mask))
                                continue;

                        WARN_ON_ONCE(!event);

                        if (!event->attr.precise_ip)
                                continue;

                        if (__test_and_set_bit(bit, (unsigned long *)&status))
                                continue;

                        break;
                }

                if (!event || bit >= x86_pmu.max_pebs_events)
                        continue;

                __intel_pmu_pebs_event(event, iregs, at);
        }
}

/*
 * BTS, PEBS probe and setup
 */

void intel_ds_init(void)
{
        /*
         * No support for 32bit formats
         */
        if (!boot_cpu_has(X86_FEATURE_DTES64))
                return;

        x86_pmu.bts  = boot_cpu_has(X86_FEATURE_BTS);
        x86_pmu.pebs = boot_cpu_has(X86_FEATURE_PEBS);
        if (x86_pmu.pebs) {
                char pebs_type = x86_pmu.intel_cap.pebs_trap ?  '+' : '-';
                int format = x86_pmu.intel_cap.pebs_format;

                switch (format) {
                case 0:
                        printk(KERN_CONT "PEBS fmt0%c, ", pebs_type);
                        x86_pmu.pebs_record_size = sizeof(struct pebs_record_core);
                        x86_pmu.drain_pebs = intel_pmu_drain_pebs_core;
                        break;

                case 1:
                        printk(KERN_CONT "PEBS fmt1%c, ", pebs_type);
                        x86_pmu.pebs_record_size = sizeof(struct pebs_record_nhm);
                        x86_pmu.drain_pebs = intel_pmu_drain_pebs_nhm;
                        break;

                default:
                        printk(KERN_CONT "no PEBS fmt%d%c, ", format, pebs_type);
                        x86_pmu.pebs = 0;
                }
        }
}

void perf_restore_debug_store(void)
{
        struct debug_store *ds = __this_cpu_read(cpu_hw_events.ds);

        if (!x86_pmu.bts && !x86_pmu.pebs)
                return;

        wrmsrl(MSR_IA32_DS_AREA, (unsigned long)ds);
}