#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 << 4)
#define PEBS_FIXUP_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;
};

 */

union intel_x86_pebs_dse {
        u64 val;
        struct {
                unsigned int ld_dse:4;
                unsigned int ld_stlb_miss:1;
                unsigned int ld_locked:1;
                unsigned int ld_reserved:26;
        };
        struct {
                unsigned int st_l1d_hit:1;
                unsigned int st_reserved1:3;
                unsigned int st_stlb_miss:1;
                unsigned int st_locked:1;
                unsigned int st_reserved2:26;
        };
};


/*
 * Map PEBS Load Latency Data Source encodings to generic
 * memory data source information
 */
#define P(a, b) PERF_MEM_S(a, b)
#define OP_LH (P(OP, LOAD) | P(LVL, HIT))
#define SNOOP_NONE_MISS (P(SNOOP, NONE) | P(SNOOP, MISS))

/* Version for Sandy Bridge and later */
static u64 pebs_data_source[] = {
        P(OP, LOAD) | P(LVL, MISS) | P(LVL, L3) | P(SNOOP, NA),/* 0x00:ukn L3 */
        OP_LH | P(LVL, L1)  | P(SNOOP, NONE),   /* 0x01: L1 local */
        OP_LH | P(LVL, LFB) | P(SNOOP, NONE),   /* 0x02: LFB hit */
        OP_LH | P(LVL, L2)  | P(SNOOP, NONE),   /* 0x03: L2 hit */
        OP_LH | P(LVL, L3)  | P(SNOOP, NONE),   /* 0x04: L3 hit */
        OP_LH | P(LVL, L3)  | P(SNOOP, MISS),   /* 0x05: L3 hit, snoop miss */
        OP_LH | P(LVL, L3)  | P(SNOOP, HIT),    /* 0x06: L3 hit, snoop hit */
        OP_LH | P(LVL, L3)  | P(SNOOP, HITM),   /* 0x07: L3 hit, snoop hitm */
        OP_LH | P(LVL, REM_CCE1) | P(SNOOP, HIT),  /* 0x08: L3 miss snoop hit */
        OP_LH | P(LVL, REM_CCE1) | P(SNOOP, HITM), /* 0x09: L3 miss snoop hitm*/
        OP_LH | P(LVL, LOC_RAM)  | P(SNOOP, HIT),  /* 0x0a: L3 miss, shared */
        OP_LH | P(LVL, REM_RAM1) | P(SNOOP, HIT),  /* 0x0b: L3 miss, shared */
        OP_LH | P(LVL, LOC_RAM)  | SNOOP_NONE_MISS,/* 0x0c: L3 miss, excl */
        OP_LH | P(LVL, REM_RAM1) | SNOOP_NONE_MISS,/* 0x0d: L3 miss, excl */
        OP_LH | P(LVL, IO)  | P(SNOOP, NONE), /* 0x0e: I/O */
        OP_LH | P(LVL, UNC) | P(SNOOP, NONE), /* 0x0f: uncached */
};

/* Patch up minor differences in the bits */
void __init intel_pmu_pebs_data_source_nhm(void)
{
        pebs_data_source[0x05] = OP_LH | P(LVL, L3)  | P(SNOOP, HIT);
        pebs_data_source[0x06] = OP_LH | P(LVL, L3)  | P(SNOOP, HITM);
        pebs_data_source[0x07] = OP_LH | P(LVL, L3)  | P(SNOOP, HITM);
}

static u64 precise_store_data(u64 status)
{
        union intel_x86_pebs_dse dse;
        u64 val = P(OP, STORE) | P(SNOOP, NA) | P(LVL, L1) | P(TLB, L2);

        dse.val = status;

        /*
         * bit 4: TLB access
         * 1 = stored missed 2nd level TLB
         *
         * so it either hit the walker or the OS
         * otherwise hit 2nd level TLB
         */
        if (dse.st_stlb_miss)
                val |= P(TLB, MISS);
        else
                val |= P(TLB, HIT);

        /*
         * bit 0: hit L1 data cache
         * if not set, then all we know is that
         * it missed L1D
         */
        if (dse.st_l1d_hit)
                val |= P(LVL, HIT);
        else
                val |= P(LVL, MISS);

        /*
         * bit 5: Locked prefix
         */
        if (dse.st_locked)
                val |= P(LOCK, LOCKED);

        return val;
}

static u64 precise_datala_hsw(struct perf_event *event, u64 status)
{
        union perf_mem_data_src dse;

        dse.val = PERF_MEM_NA;

        if (event->hw.flags & PERF_X86_EVENT_PEBS_ST_HSW)
                dse.mem_op = PERF_MEM_OP_STORE;
        else if (event->hw.flags & PERF_X86_EVENT_PEBS_LD_HSW)
                dse.mem_op = PERF_MEM_OP_LOAD;

        /*
         * L1 info only valid for following events:
         *
         * MEM_UOPS_RETIRED.STLB_MISS_STORES
         * MEM_UOPS_RETIRED.LOCK_STORES
         * MEM_UOPS_RETIRED.SPLIT_STORES
         * MEM_UOPS_RETIRED.ALL_STORES
         */
        if (event->hw.flags & PERF_X86_EVENT_PEBS_ST_HSW) {
                if (status & 1)
                        dse.mem_lvl = PERF_MEM_LVL_L1 | PERF_MEM_LVL_HIT;
                else
                        dse.mem_lvl = PERF_MEM_LVL_L1 | PERF_MEM_LVL_MISS;
        }
        return dse.val;
}

static u64 load_latency_data(u64 status)
{
        union intel_x86_pebs_dse dse;
        u64 val;
        int model = boot_cpu_data.x86_model;
        int fam = boot_cpu_data.x86;

        dse.val = status;

        /*
         * use the mapping table for bit 0-3
         */
        val = pebs_data_source[dse.ld_dse];

        /*
         * Nehalem models do not support TLB, Lock infos
         */
        if (fam == 0x6 && (model == 26 || model == 30
            || model == 31 || model == 46)) {
                val |= P(TLB, NA) | P(LOCK, NA);
                return val;
        }
        /*
         * bit 4: TLB access
         * 0 = did not miss 2nd level TLB
         * 1 = missed 2nd level TLB
         */
        if (dse.ld_stlb_miss)
                val |= P(TLB, MISS) | P(TLB, L2);
        else
                val |= P(TLB, HIT) | P(TLB, L1) | P(TLB, L2);

        /*
         * bit 5: locked prefix
         */
        if (dse.ld_locked)
                val |= P(LOCK, LOCKED);

        return val;
}

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;
};

/*
 * Same as pebs_record_nhm, with two additional fields.
 */
struct pebs_record_hsw {
        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;
        u64 real_ip, tsx_tuning;
};

union hsw_tsx_tuning {
        struct {
                u32 cycles_last_block     : 32,
                    hle_abort             : 1,
                    rtm_abort             : 1,
                    instruction_abort     : 1,
                    non_instruction_abort : 1,
                    retry                 : 1,
                    data_conflict         : 1,
                    capacity_writes       : 1,
                    capacity_reads        : 1;
        };
        u64         value;
};

#define PEBS_HSW_TSX_FLAGS      0xff00000000ULL

/* Same as HSW, plus TSC */

struct pebs_record_skl {
        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;
        u64 real_ip, tsx_tuning;
        u64 tsc;
};

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 DEFINE_PER_CPU(void *, insn_buffer);

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;
        void *buffer, *ibuffer;

        if (!x86_pmu.pebs)
                return 0;

        buffer = kzalloc_node(x86_pmu.pebs_buffer_size, GFP_KERNEL, node);
        if (unlikely(!buffer))
                return -ENOMEM;

        /*
         * HSW+ already provides us the eventing ip; no need to allocate this
         * buffer then.
         */
        if (x86_pmu.intel_cap.pebs_format < 2) {
                ibuffer = kzalloc_node(PEBS_FIXUP_SIZE, GFP_KERNEL, node);
                if (!ibuffer) {
                        kfree(buffer);
                        return -ENOMEM;
                }
                per_cpu(insn_buffer, cpu) = ibuffer;
        }

        max = x86_pmu.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;

        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(per_cpu(insn_buffer, cpu));
        per_cpu(insn_buffer, cpu) = NULL;

        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 = kzalloc_node(BTS_BUFFER_SIZE, GFP_KERNEL | __GFP_NOWARN, node);
        if (unlikely(!buffer)) {
                WARN_ONCE(1, "%s: BTS buffer allocation failure\n", __func__);
                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 = kzalloc_node(sizeof(*ds), GFP_KERNEL, 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;
        if (config & ARCH_PERFMON_EVENTSEL_INT)
                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 = this_cpu_ptr(&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 = this_cpu_ptr(&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, *base, *top;
        struct perf_output_handle handle;
        struct perf_event_header header;
        struct perf_sample_data data;
        unsigned long skip = 0;
        struct pt_regs regs;

        if (!event)
                return 0;

        if (!x86_pmu.bts_active)
                return 0;

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

        if (top <= base)
                return 0;

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

        ds->bts_index = ds->bts_buffer_base;

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

        /*
         * BTS leaks kernel addresses in branches across the cpl boundary,
         * such as traps or system calls, so unless the user is asking for
         * kernel tracing (and right now it's not possible), we'd need to
         * filter them out. But first we need to count how many of those we
         * have in the current batch. This is an extra O(n) pass, however,
         * it's much faster than the other one especially considering that
         * n <= 2560 (BTS_BUFFER_SIZE / BTS_RECORD_SIZE * 15/16; see the
         * alloc_bts_buffer()).
         */
        for (at = base; at < top; at++) {
                /*
                 * Note that right now *this* BTS code only works if
                 * attr::exclude_kernel is set, but let's keep this extra
                 * check here in case that changes.
                 */
                if (event->attr.exclude_kernel &&
                    (kernel_ip(at->from) || kernel_ip(at->to)))
                        skip++;
        }

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

        if (perf_output_begin(&handle, event, header.size *
                              (top - base - skip)))
                goto unlock;

        for (at = base; at < top; at++) {
                /* Filter out any records that contain kernel addresses. */
                if (event->attr.exclude_kernel &&
                    (kernel_ip(at->from) || kernel_ip(at->to)))
                        continue;

                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;
unlock:
        rcu_read_unlock();
        return 1;
}

static inline void intel_pmu_drain_pebs_buffer(void)
{
        struct pt_regs regs;

        x86_pmu.drain_pebs(&regs);
}

void intel_pmu_pebs_sched_task(struct perf_event_context *ctx, bool sched_in)
{
        if (!sched_in)
                intel_pmu_drain_pebs_buffer();
}

/*
 * PEBS
 */
struct event_constraint intel_core2_pebs_event_constraints[] = {
        INTEL_FLAGS_UEVENT_CONSTRAINT(0x00c0, 0x1), /* INST_RETIRED.ANY */
        INTEL_FLAGS_UEVENT_CONSTRAINT(0xfec1, 0x1), /* X87_OPS_RETIRED.ANY */
        INTEL_FLAGS_UEVENT_CONSTRAINT(0x00c5, 0x1), /* BR_INST_RETIRED.MISPRED */
        INTEL_FLAGS_UEVENT_CONSTRAINT(0x1fc7, 0x1), /* SIMD_INST_RETURED.ANY */
        INTEL_FLAGS_EVENT_CONSTRAINT(0xcb, 0x1),    /* MEM_LOAD_RETIRED.* */
        /* INST_RETIRED.ANY_P, inv=1, cmask=16 (cycles:p). */
        INTEL_FLAGS_EVENT_CONSTRAINT(0x108000c0, 0x01),
        EVENT_CONSTRAINT_END
};

struct event_constraint intel_atom_pebs_event_constraints[] = {
        INTEL_FLAGS_UEVENT_CONSTRAINT(0x00c0, 0x1), /* INST_RETIRED.ANY */
        INTEL_FLAGS_UEVENT_CONSTRAINT(0x00c5, 0x1), /* MISPREDICTED_BRANCH_RETIRED */
        INTEL_FLAGS_EVENT_CONSTRAINT(0xcb, 0x1),    /* MEM_LOAD_RETIRED.* */
        /* INST_RETIRED.ANY_P, inv=1, cmask=16 (cycles:p). */
        INTEL_FLAGS_EVENT_CONSTRAINT(0x108000c0, 0x01),
        /* Allow all events as PEBS with no flags */
        INTEL_ALL_EVENT_CONSTRAINT(0, 0x1),
        EVENT_CONSTRAINT_END
};

struct event_constraint intel_slm_pebs_event_constraints[] = {
        /* INST_RETIRED.ANY_P, inv=1, cmask=16 (cycles:p). */
        INTEL_FLAGS_EVENT_CONSTRAINT(0x108000c0, 0x1),
        /* Allow all events as PEBS with no flags */
        INTEL_ALL_EVENT_CONSTRAINT(0, 0x1),
        EVENT_CONSTRAINT_END
};

struct event_constraint intel_nehalem_pebs_event_constraints[] = {
        INTEL_PLD_CONSTRAINT(0x100b, 0xf),      /* MEM_INST_RETIRED.* */
        INTEL_FLAGS_EVENT_CONSTRAINT(0x0f, 0xf),    /* MEM_UNCORE_RETIRED.* */
        INTEL_FLAGS_UEVENT_CONSTRAINT(0x010c, 0xf), /* MEM_STORE_RETIRED.DTLB_MISS */
        INTEL_FLAGS_EVENT_CONSTRAINT(0xc0, 0xf),    /* INST_RETIRED.ANY */
        INTEL_EVENT_CONSTRAINT(0xc2, 0xf),    /* UOPS_RETIRED.* */
        INTEL_FLAGS_EVENT_CONSTRAINT(0xc4, 0xf),    /* BR_INST_RETIRED.* */
        INTEL_FLAGS_UEVENT_CONSTRAINT(0x02c5, 0xf), /* BR_MISP_RETIRED.NEAR_CALL */
        INTEL_FLAGS_EVENT_CONSTRAINT(0xc7, 0xf),    /* SSEX_UOPS_RETIRED.* */
        INTEL_FLAGS_UEVENT_CONSTRAINT(0x20c8, 0xf), /* ITLB_MISS_RETIRED */
        INTEL_FLAGS_EVENT_CONSTRAINT(0xcb, 0xf),    /* MEM_LOAD_RETIRED.* */
        INTEL_FLAGS_EVENT_CONSTRAINT(0xf7, 0xf),    /* FP_ASSIST.* */
        /* INST_RETIRED.ANY_P, inv=1, cmask=16 (cycles:p). */
        INTEL_FLAGS_EVENT_CONSTRAINT(0x108000c0, 0x0f),
        EVENT_CONSTRAINT_END
};

struct event_constraint intel_westmere_pebs_event_constraints[] = {
        INTEL_PLD_CONSTRAINT(0x100b, 0xf),      /* MEM_INST_RETIRED.* */
        INTEL_FLAGS_EVENT_CONSTRAINT(0x0f, 0xf),    /* MEM_UNCORE_RETIRED.* */
        INTEL_FLAGS_UEVENT_CONSTRAINT(0x010c, 0xf), /* MEM_STORE_RETIRED.DTLB_MISS */
        INTEL_FLAGS_EVENT_CONSTRAINT(0xc0, 0xf),    /* INSTR_RETIRED.* */
        INTEL_EVENT_CONSTRAINT(0xc2, 0xf),    /* UOPS_RETIRED.* */
        INTEL_FLAGS_EVENT_CONSTRAINT(0xc4, 0xf),    /* BR_INST_RETIRED.* */
        INTEL_FLAGS_EVENT_CONSTRAINT(0xc5, 0xf),    /* BR_MISP_RETIRED.* */
        INTEL_FLAGS_EVENT_CONSTRAINT(0xc7, 0xf),    /* SSEX_UOPS_RETIRED.* */
        INTEL_FLAGS_UEVENT_CONSTRAINT(0x20c8, 0xf), /* ITLB_MISS_RETIRED */
        INTEL_FLAGS_EVENT_CONSTRAINT(0xcb, 0xf),    /* MEM_LOAD_RETIRED.* */
        INTEL_FLAGS_EVENT_CONSTRAINT(0xf7, 0xf),    /* FP_ASSIST.* */
        /* INST_RETIRED.ANY_P, inv=1, cmask=16 (cycles:p). */
        INTEL_FLAGS_EVENT_CONSTRAINT(0x108000c0, 0x0f),
        EVENT_CONSTRAINT_END
};

struct event_constraint intel_snb_pebs_event_constraints[] = {
        INTEL_FLAGS_UEVENT_CONSTRAINT(0x01c0, 0x2), /* INST_RETIRED.PRECDIST */
        INTEL_PLD_CONSTRAINT(0x01cd, 0x8),    /* MEM_TRANS_RETIRED.LAT_ABOVE_THR */
        INTEL_PST_CONSTRAINT(0x02cd, 0x8),    /* MEM_TRANS_RETIRED.PRECISE_STORES */
        /* UOPS_RETIRED.ALL, inv=1, cmask=16 (cycles:p). */
        INTEL_FLAGS_EVENT_CONSTRAINT(0x108001c2, 0xf),
        INTEL_EXCLEVT_CONSTRAINT(0xd0, 0xf),    /* MEM_UOP_RETIRED.* */
        INTEL_EXCLEVT_CONSTRAINT(0xd1, 0xf),    /* MEM_LOAD_UOPS_RETIRED.* */
        INTEL_EXCLEVT_CONSTRAINT(0xd2, 0xf),    /* MEM_LOAD_UOPS_LLC_HIT_RETIRED.* */
        INTEL_EXCLEVT_CONSTRAINT(0xd3, 0xf),    /* MEM_LOAD_UOPS_LLC_MISS_RETIRED.* */
        /* Allow all events as PEBS with no flags */
        INTEL_ALL_EVENT_CONSTRAINT(0, 0xf),
        EVENT_CONSTRAINT_END
};

struct event_constraint intel_ivb_pebs_event_constraints[] = {
        INTEL_FLAGS_UEVENT_CONSTRAINT(0x01c0, 0x2), /* INST_RETIRED.PRECDIST */
        INTEL_PLD_CONSTRAINT(0x01cd, 0x8),    /* MEM_TRANS_RETIRED.LAT_ABOVE_THR */
        INTEL_PST_CONSTRAINT(0x02cd, 0x8),    /* MEM_TRANS_RETIRED.PRECISE_STORES */
        /* UOPS_RETIRED.ALL, inv=1, cmask=16 (cycles:p). */
        INTEL_FLAGS_EVENT_CONSTRAINT(0x108001c2, 0xf),
        /* INST_RETIRED.PREC_DIST, inv=1, cmask=16 (cycles:ppp). */
        INTEL_FLAGS_EVENT_CONSTRAINT(0x108001c0, 0x2),
        INTEL_EXCLEVT_CONSTRAINT(0xd0, 0xf),    /* MEM_UOP_RETIRED.* */
        INTEL_EXCLEVT_CONSTRAINT(0xd1, 0xf),    /* MEM_LOAD_UOPS_RETIRED.* */
        INTEL_EXCLEVT_CONSTRAINT(0xd2, 0xf),    /* MEM_LOAD_UOPS_LLC_HIT_RETIRED.* */
        INTEL_EXCLEVT_CONSTRAINT(0xd3, 0xf),    /* MEM_LOAD_UOPS_LLC_MISS_RETIRED.* */
        /* Allow all events as PEBS with no flags */
        INTEL_ALL_EVENT_CONSTRAINT(0, 0xf),
        EVENT_CONSTRAINT_END
};

struct event_constraint intel_hsw_pebs_event_constraints[] = {
        INTEL_FLAGS_UEVENT_CONSTRAINT(0x01c0, 0x2), /* INST_RETIRED.PRECDIST */
        INTEL_PLD_CONSTRAINT(0x01cd, 0xf),    /* MEM_TRANS_RETIRED.* */
        /* UOPS_RETIRED.ALL, inv=1, cmask=16 (cycles:p). */
        INTEL_FLAGS_EVENT_CONSTRAINT(0x108001c2, 0xf),
        /* INST_RETIRED.PREC_DIST, inv=1, cmask=16 (cycles:ppp). */
        INTEL_FLAGS_EVENT_CONSTRAINT(0x108001c0, 0x2),
        INTEL_FLAGS_UEVENT_CONSTRAINT_DATALA_NA(0x01c2, 0xf), /* UOPS_RETIRED.ALL */
        INTEL_FLAGS_UEVENT_CONSTRAINT_DATALA_XLD(0x11d0, 0xf), /* MEM_UOPS_RETIRED.STLB_MISS_LOADS */
        INTEL_FLAGS_UEVENT_CONSTRAINT_DATALA_XLD(0x21d0, 0xf), /* MEM_UOPS_RETIRED.LOCK_LOADS */
        INTEL_FLAGS_UEVENT_CONSTRAINT_DATALA_XLD(0x41d0, 0xf), /* MEM_UOPS_RETIRED.SPLIT_LOADS */
        INTEL_FLAGS_UEVENT_CONSTRAINT_DATALA_XLD(0x81d0, 0xf), /* MEM_UOPS_RETIRED.ALL_LOADS */
        INTEL_FLAGS_UEVENT_CONSTRAINT_DATALA_XST(0x12d0, 0xf), /* MEM_UOPS_RETIRED.STLB_MISS_STORES */
        INTEL_FLAGS_UEVENT_CONSTRAINT_DATALA_XST(0x42d0, 0xf), /* MEM_UOPS_RETIRED.SPLIT_STORES */
        INTEL_FLAGS_UEVENT_CONSTRAINT_DATALA_XST(0x82d0, 0xf), /* MEM_UOPS_RETIRED.ALL_STORES */
        INTEL_FLAGS_EVENT_CONSTRAINT_DATALA_XLD(0xd1, 0xf),    /* MEM_LOAD_UOPS_RETIRED.* */
        INTEL_FLAGS_EVENT_CONSTRAINT_DATALA_XLD(0xd2, 0xf),    /* MEM_LOAD_UOPS_L3_HIT_RETIRED.* */
        INTEL_FLAGS_EVENT_CONSTRAINT_DATALA_XLD(0xd3, 0xf),    /* MEM_LOAD_UOPS_L3_MISS_RETIRED.* */
        /* Allow all events as PEBS with no flags */
        INTEL_ALL_EVENT_CONSTRAINT(0, 0xf),
        EVENT_CONSTRAINT_END
};

struct event_constraint intel_bdw_pebs_event_constraints[] = {
        INTEL_FLAGS_UEVENT_CONSTRAINT(0x01c0, 0x2), /* INST_RETIRED.PRECDIST */
        INTEL_PLD_CONSTRAINT(0x01cd, 0xf),    /* MEM_TRANS_RETIRED.* */
        /* UOPS_RETIRED.ALL, inv=1, cmask=16 (cycles:p). */
        INTEL_FLAGS_EVENT_CONSTRAINT(0x108001c2, 0xf),
        /* INST_RETIRED.PREC_DIST, inv=1, cmask=16 (cycles:ppp). */
        INTEL_FLAGS_EVENT_CONSTRAINT(0x108001c0, 0x2),
        INTEL_FLAGS_UEVENT_CONSTRAINT_DATALA_NA(0x01c2, 0xf), /* UOPS_RETIRED.ALL */
        INTEL_FLAGS_UEVENT_CONSTRAINT_DATALA_LD(0x11d0, 0xf), /* MEM_UOPS_RETIRED.STLB_MISS_LOADS */
        INTEL_FLAGS_UEVENT_CONSTRAINT_DATALA_LD(0x21d0, 0xf), /* MEM_UOPS_RETIRED.LOCK_LOADS */
        INTEL_FLAGS_UEVENT_CONSTRAINT_DATALA_LD(0x41d0, 0xf), /* MEM_UOPS_RETIRED.SPLIT_LOADS */
        INTEL_FLAGS_UEVENT_CONSTRAINT_DATALA_LD(0x81d0, 0xf), /* MEM_UOPS_RETIRED.ALL_LOADS */
        INTEL_FLAGS_UEVENT_CONSTRAINT_DATALA_ST(0x12d0, 0xf), /* MEM_UOPS_RETIRED.STLB_MISS_STORES */
        INTEL_FLAGS_UEVENT_CONSTRAINT_DATALA_ST(0x42d0, 0xf), /* MEM_UOPS_RETIRED.SPLIT_STORES */
        INTEL_FLAGS_UEVENT_CONSTRAINT_DATALA_ST(0x82d0, 0xf), /* MEM_UOPS_RETIRED.ALL_STORES */
        INTEL_FLAGS_EVENT_CONSTRAINT_DATALA_LD(0xd1, 0xf),    /* MEM_LOAD_UOPS_RETIRED.* */
        INTEL_FLAGS_EVENT_CONSTRAINT_DATALA_LD(0xd2, 0xf),    /* MEM_LOAD_UOPS_L3_HIT_RETIRED.* */
        INTEL_FLAGS_EVENT_CONSTRAINT_DATALA_LD(0xd3, 0xf),    /* MEM_LOAD_UOPS_L3_MISS_RETIRED.* */
        /* Allow all events as PEBS with no flags */
        INTEL_ALL_EVENT_CONSTRAINT(0, 0xf),
        EVENT_CONSTRAINT_END
};


struct event_constraint intel_skl_pebs_event_constraints[] = {
        INTEL_FLAGS_UEVENT_CONSTRAINT(0x1c0, 0x2),      /* INST_RETIRED.PREC_DIST */
        /* INST_RETIRED.PREC_DIST, inv=1, cmask=16 (cycles:ppp). */
        INTEL_FLAGS_EVENT_CONSTRAINT(0x108001c0, 0x2),
        /* INST_RETIRED.TOTAL_CYCLES_PS (inv=1, cmask=16) (cycles:p). */
        INTEL_FLAGS_EVENT_CONSTRAINT(0x108000c0, 0x0f),
        INTEL_PLD_CONSTRAINT(0x1cd, 0xf),                     /* MEM_TRANS_RETIRED.* */
        INTEL_FLAGS_UEVENT_CONSTRAINT_DATALA_LD(0x11d0, 0xf), /* MEM_INST_RETIRED.STLB_MISS_LOADS */
        INTEL_FLAGS_UEVENT_CONSTRAINT_DATALA_ST(0x12d0, 0xf), /* MEM_INST_RETIRED.STLB_MISS_STORES */
        INTEL_FLAGS_UEVENT_CONSTRAINT_DATALA_LD(0x21d0, 0xf), /* MEM_INST_RETIRED.LOCK_LOADS */
        INTEL_FLAGS_UEVENT_CONSTRAINT_DATALA_ST(0x22d0, 0xf), /* MEM_INST_RETIRED.LOCK_STORES */
        INTEL_FLAGS_UEVENT_CONSTRAINT_DATALA_LD(0x41d0, 0xf), /* MEM_INST_RETIRED.SPLIT_LOADS */
        INTEL_FLAGS_UEVENT_CONSTRAINT_DATALA_ST(0x42d0, 0xf), /* MEM_INST_RETIRED.SPLIT_STORES */
        INTEL_FLAGS_UEVENT_CONSTRAINT_DATALA_LD(0x81d0, 0xf), /* MEM_INST_RETIRED.ALL_LOADS */
        INTEL_FLAGS_UEVENT_CONSTRAINT_DATALA_ST(0x82d0, 0xf), /* MEM_INST_RETIRED.ALL_STORES */
        INTEL_FLAGS_EVENT_CONSTRAINT_DATALA_LD(0xd1, 0xf),    /* MEM_LOAD_RETIRED.* */
        INTEL_FLAGS_EVENT_CONSTRAINT_DATALA_LD(0xd2, 0xf),    /* MEM_LOAD_L3_HIT_RETIRED.* */
        INTEL_FLAGS_EVENT_CONSTRAINT_DATALA_LD(0xd3, 0xf),    /* MEM_LOAD_L3_MISS_RETIRED.* */
        /* Allow all events as PEBS with no flags */
        INTEL_ALL_EVENT_CONSTRAINT(0, 0xf),
        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) {
                                event->hw.flags |= c->flags;
                                return c;
                        }
                }
        }

        return &emptyconstraint;
}

static inline bool pebs_is_enabled(struct cpu_hw_events *cpuc)
{
        return (cpuc->pebs_enabled & ((1ULL << MAX_PEBS_EVENTS) - 1));
}

void intel_pmu_pebs_enable(struct perf_event *event)
{
        struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
        struct hw_perf_event *hwc = &event->hw;
        struct debug_store *ds = cpuc->ds;
        bool first_pebs;
        u64 threshold;

        hwc->config &= ~ARCH_PERFMON_EVENTSEL_INT;

        first_pebs = !pebs_is_enabled(cpuc);
        cpuc->pebs_enabled |= 1ULL << hwc->idx;

        if (event->hw.flags & PERF_X86_EVENT_PEBS_LDLAT)
                cpuc->pebs_enabled |= 1ULL << (hwc->idx + 32);
        else if (event->hw.flags & PERF_X86_EVENT_PEBS_ST)
                cpuc->pebs_enabled |= 1ULL << 63;

        /*
         * When the event is constrained enough we can use a larger
         * threshold and run the event with less frequent PMI.
         */
        if (hwc->flags & PERF_X86_EVENT_FREERUNNING) {
                threshold = ds->pebs_absolute_maximum -
                        x86_pmu.max_pebs_events * x86_pmu.pebs_record_size;

                if (first_pebs)
                        perf_sched_cb_inc(event->ctx->pmu);
        } else {
                threshold = ds->pebs_buffer_base + x86_pmu.pebs_record_size;

                /*
                 * If not all events can use larger buffer,
                 * roll back to threshold = 1
                 */
                if (!first_pebs &&
                    (ds->pebs_interrupt_threshold > threshold))
                        perf_sched_cb_dec(event->ctx->pmu);
        }

        /* Use auto-reload if possible to save a MSR write in the PMI */
        if (hwc->flags & PERF_X86_EVENT_AUTO_RELOAD) {
                ds->pebs_event_reset[hwc->idx] =
                        (u64)(-hwc->sample_period) & x86_pmu.cntval_mask;
        }

        if (first_pebs || ds->pebs_interrupt_threshold > threshold)
                ds->pebs_interrupt_threshold = threshold;
}

void intel_pmu_pebs_disable(struct perf_event *event)
{
        struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
        struct hw_perf_event *hwc = &event->hw;
        struct debug_store *ds = cpuc->ds;
        bool large_pebs = ds->pebs_interrupt_threshold >
                ds->pebs_buffer_base + x86_pmu.pebs_record_size;

        if (large_pebs)
                intel_pmu_drain_pebs_buffer();

        cpuc->pebs_enabled &= ~(1ULL << hwc->idx);

        if (event->hw.flags & PERF_X86_EVENT_PEBS_LDLAT)
                cpuc->pebs_enabled &= ~(1ULL << (hwc->idx + 32));
        else if (event->hw.flags & PERF_X86_EVENT_PEBS_ST)
                cpuc->pebs_enabled &= ~(1ULL << 63);

        if (large_pebs && !pebs_is_enabled(cpuc))
                perf_sched_cb_dec(event->ctx->pmu);

        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 = this_cpu_ptr(&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 = this_cpu_ptr(&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 = this_cpu_ptr(&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;
        void *kaddr;
        int size;

        /*
         * 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) > PEBS_FIXUP_SIZE)
                return 0;

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

        size = ip - to;
        if (!kernel_ip(ip)) {
                int bytes;
                u8 *buf = this_cpu_read(insn_buffer);

                /* 'size' must fit our buffer, see above */
                bytes = copy_from_user_nmi(buf, (void __user *)to, size);
                if (bytes != 0)
                        return 0;

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

        do {
                struct insn insn;

                old_to = to;

#ifdef CONFIG_X86_64
                is_64bit = kernel_ip(to) || !test_thread_flag(TIF_IA32);
#endif
                insn_init(&insn, kaddr, size, is_64bit);
                insn_get_length(&insn);
                /*
                 * Make sure there was not a problem decoding the
                 * instruction and getting the length.  This is
                 * doubly important because we have an infinite
                 * loop if insn.length=0.
                 */
                if (!insn.length)
                        break;

                to += insn.length;
                kaddr += insn.length;
                size -= 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 inline u64 intel_hsw_weight(struct pebs_record_skl *pebs)
{
        if (pebs->tsx_tuning) {
                union hsw_tsx_tuning tsx = { .value = pebs->tsx_tuning };
                return tsx.cycles_last_block;
        }

        return 0;
}

static inline u64 intel_hsw_transaction(struct pebs_record_skl *pebs)
{
        u64 txn = (pebs->tsx_tuning & PEBS_HSW_TSX_FLAGS) >> 32;

        /* For RTM XABORTs also log the abort code from AX */
        if ((txn & PERF_TXN_TRANSACTION) && (pebs->ax & 1))
                txn |= ((pebs->ax >> 24) & 0xff) << PERF_TXN_ABORT_SHIFT;
        return txn;
}

static void setup_pebs_sample_data(struct perf_event *event,
                                   struct pt_regs *iregs, void *__pebs,
                                   struct perf_sample_data *data,
                                   struct pt_regs *regs)
{
#define PERF_X86_EVENT_PEBS_HSW_PREC \
                (PERF_X86_EVENT_PEBS_ST_HSW | \
                 PERF_X86_EVENT_PEBS_LD_HSW | \
                 PERF_X86_EVENT_PEBS_NA_HSW)
        /*
         * We cast to the biggest pebs_record but are careful not to
         * unconditionally access the 'extra' entries.
         */
        struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
        struct pebs_record_skl *pebs = __pebs;
        u64 sample_type;
        int fll, fst, dsrc;
        int fl = event->hw.flags;

        if (pebs == NULL)
                return;

        sample_type = event->attr.sample_type;
        dsrc = sample_type & PERF_SAMPLE_DATA_SRC;

        fll = fl & PERF_X86_EVENT_PEBS_LDLAT;
        fst = fl & (PERF_X86_EVENT_PEBS_ST | PERF_X86_EVENT_PEBS_HSW_PREC);

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

        data->period = event->hw.last_period;

        /*
         * Use latency for weight (only avail with PEBS-LL)
         */
        if (fll && (sample_type & PERF_SAMPLE_WEIGHT))
                data->weight = pebs->lat;

        /*
         * data.data_src encodes the data source
         */
        if (dsrc) {
                u64 val = PERF_MEM_NA;
                if (fll)
                        val = load_latency_data(pebs->dse);
                else if (fst && (fl & PERF_X86_EVENT_PEBS_HSW_PREC))
                        val = precise_datala_hsw(event, pebs->dse);
                else if (fst)
                        val = precise_store_data(pebs->dse);
                data->data_src.val = val;
        }

        /*
         * 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 (sample_type & PERF_SAMPLE_REGS_INTR) {
                regs->ax = pebs->ax;
                regs->bx = pebs->bx;
                regs->cx = pebs->cx;
                regs->dx = pebs->dx;
                regs->si = pebs->si;
                regs->di = pebs->di;
                regs->bp = pebs->bp;
                regs->sp = pebs->sp;

                regs->flags = pebs->flags;
#ifndef CONFIG_X86_32
                regs->r8 = pebs->r8;
                regs->r9 = pebs->r9;
                regs->r10 = pebs->r10;
                regs->r11 = pebs->r11;
                regs->r12 = pebs->r12;
                regs->r13 = pebs->r13;
                regs->r14 = pebs->r14;
                regs->r15 = pebs->r15;
#endif
        }

        if (event->attr.precise_ip > 1 && x86_pmu.intel_cap.pebs_format >= 2) {
                regs->ip = pebs->real_ip;
                regs->flags |= PERF_EFLAGS_EXACT;
        } else if (event->attr.precise_ip > 1 && intel_pmu_pebs_fixup_ip(regs))
                regs->flags |= PERF_EFLAGS_EXACT;
        else
                regs->flags &= ~PERF_EFLAGS_EXACT;

        if ((sample_type & PERF_SAMPLE_ADDR) &&
            x86_pmu.intel_cap.pebs_format >= 1)
                data->addr = pebs->dla;

        if (x86_pmu.intel_cap.pebs_format >= 2) {
                /* Only set the TSX weight when no memory weight. */
                if ((sample_type & PERF_SAMPLE_WEIGHT) && !fll)
                        data->weight = intel_hsw_weight(pebs);

                if (sample_type & PERF_SAMPLE_TRANSACTION)
                        data->txn = intel_hsw_transaction(pebs);
        }

        /*
         * v3 supplies an accurate time stamp, so we use that
         * for the time stamp.
         *
         * We can only do this for the default trace clock.
         */
        if (x86_pmu.intel_cap.pebs_format >= 3 &&
                event->attr.use_clockid == 0)
                data->time = native_sched_clock_from_tsc(pebs->tsc);

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

static inline void *
get_next_pebs_record_by_bit(void *base, void *top, int bit)
{
        struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
        void *at;
        u64 pebs_status;

        /*
         * fmt0 does not have a status bitfield (does not use
         * perf_record_nhm format)
         */
        if (x86_pmu.intel_cap.pebs_format < 1)
                return base;

        if (base == NULL)
                return NULL;

        for (at = base; at < top; at += x86_pmu.pebs_record_size) {
                struct pebs_record_nhm *p = at;

                if (test_bit(bit, (unsigned long *)&p->status)) {
                        /* PEBS v3 has accurate status bits */
                        if (x86_pmu.intel_cap.pebs_format >= 3)
                                return at;

                        if (p->status == (1 << bit))
                                return at;

                        /* clear non-PEBS bit and re-check */
                        pebs_status = p->status & cpuc->pebs_enabled;
                        pebs_status &= (1ULL << MAX_PEBS_EVENTS) - 1;
                        if (pebs_status == (1 << bit))
                                return at;
                }
        }
        return NULL;
}

static void __intel_pmu_pebs_event(struct perf_event *event,
                                   struct pt_regs *iregs,
                                   void *base, void *top,
                                   int bit, int count)
{
        struct perf_sample_data data;
        struct pt_regs regs;
        void *at = get_next_pebs_record_by_bit(base, top, bit);

        if (!intel_pmu_save_and_restart(event) &&
            !(event->hw.flags & PERF_X86_EVENT_AUTO_RELOAD))
                return;

        while (count > 1) {
                setup_pebs_sample_data(event, iregs, at, &data, &regs);
                perf_event_output(event, &data, &regs);
                at += x86_pmu.pebs_record_size;
                at = get_next_pebs_record_by_bit(at, top, bit);
                count--;
        }

        setup_pebs_sample_data(event, iregs, at, &data, &regs);

        /*
         * All but the last records are processed.
         * The last one is left to be able to call the overflow handler.
         */
        if (perf_event_overflow(event, &data, &regs)) {
                x86_pmu_stop(event, 0);
                return;
        }

}

static void intel_pmu_drain_pebs_core(struct pt_regs *iregs)
{
        struct cpu_hw_events *cpuc = this_cpu_ptr(&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;

        __intel_pmu_pebs_event(event, iregs, at, top, 0, n);
}

static void intel_pmu_drain_pebs_nhm(struct pt_regs *iregs)
{
        struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
        struct debug_store *ds = cpuc->ds;
        struct perf_event *event;
        void *base, *at, *top;
        short counts[MAX_PEBS_EVENTS] = {};
        short error[MAX_PEBS_EVENTS] = {};
        int bit, i;

        if (!x86_pmu.pebs_active)
                return;

        base = (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;

        if (unlikely(base >= top))
                return;

        for (at = base; at < top; at += x86_pmu.pebs_record_size) {
                struct pebs_record_nhm *p = at;
                u64 pebs_status;

                /* PEBS v3 has accurate status bits */
                if (x86_pmu.intel_cap.pebs_format >= 3) {
                        for_each_set_bit(bit, (unsigned long *)&p->status,
                                         MAX_PEBS_EVENTS)
                                counts[bit]++;

                        continue;
                }

                pebs_status = p->status & cpuc->pebs_enabled;
                pebs_status &= (1ULL << x86_pmu.max_pebs_events) - 1;

                /*
                 * On some CPUs the PEBS status can be zero when PEBS is
                 * racing with clearing of GLOBAL_STATUS.
                 *
                 * Normally we would drop that record, but in the
                 * case when there is only a single active PEBS event
                 * we can assume it's for that event.
                 */
                if (!pebs_status && cpuc->pebs_enabled &&
                        !(cpuc->pebs_enabled & (cpuc->pebs_enabled-1)))
                        pebs_status = cpuc->pebs_enabled;

                bit = find_first_bit((unsigned long *)&pebs_status,
                                        x86_pmu.max_pebs_events);
                if (bit >= x86_pmu.max_pebs_events)
                        continue;

                /*
                 * The PEBS hardware does not deal well with the situation
                 * when events happen near to each other and multiple bits
                 * are set. But it should happen rarely.
                 *
                 * If these events include one PEBS and multiple non-PEBS
                 * events, it doesn't impact PEBS record. The record will
                 * be handled normally. (slow path)
                 *
                 * If these events include two or more PEBS events, the
                 * records for the events can be collapsed into a single
                 * one, and it's not possible to reconstruct all events
                 * that caused the PEBS record. It's called collision.
                 * If collision happened, the record will be dropped.
                 */
                if (p->status != (1ULL << bit)) {
                        for_each_set_bit(i, (unsigned long *)&pebs_status,
                                         x86_pmu.max_pebs_events)
                                error[i]++;
                        continue;
                }

                counts[bit]++;
        }

        for (bit = 0; bit < x86_pmu.max_pebs_events; bit++) {
                if ((counts[bit] == 0) && (error[bit] == 0))
                        continue;

                event = cpuc->events[bit];
                WARN_ON_ONCE(!event);
                WARN_ON_ONCE(!event->attr.precise_ip);

                /* log dropped samples number */
                if (error[bit])
                        perf_log_lost_samples(event, error[bit]);

                if (counts[bit]) {
                        __intel_pmu_pebs_event(event, iregs, base,
                                               top, bit, counts[bit]);
                }
        }
}

/*
 * BTS, PEBS probe and setup
 */

void __init 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);
        x86_pmu.pebs_buffer_size = PEBS_BUFFER_SIZE;
        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:
                        pr_cont("PEBS fmt0%c, ", pebs_type);
                        x86_pmu.pebs_record_size = sizeof(struct pebs_record_core);
                        /*
                         * Using >PAGE_SIZE buffers makes the WRMSR to
                         * PERF_GLOBAL_CTRL in intel_pmu_enable_all()
                         * mysteriously hang on Core2.
                         *
                         * As a workaround, we don't do this.
                         */
                        x86_pmu.pebs_buffer_size = PAGE_SIZE;
                        x86_pmu.drain_pebs = intel_pmu_drain_pebs_core;
                        break;

                case 1:
                        pr_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;

                case 2:
                        pr_cont("PEBS fmt2%c, ", pebs_type);
                        x86_pmu.pebs_record_size = sizeof(struct pebs_record_hsw);
                        x86_pmu.drain_pebs = intel_pmu_drain_pebs_nhm;
                        break;

                case 3:
                        pr_cont("PEBS fmt3%c, ", pebs_type);
                        x86_pmu.pebs_record_size =
                                                sizeof(struct pebs_record_skl);
                        x86_pmu.drain_pebs = intel_pmu_drain_pebs_nhm;
                        x86_pmu.free_running_flags |= PERF_SAMPLE_TIME;
                        break;

                default:
                        pr_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);
}