/* Copyright (C) 2021-2024 Free Software Foundation, Inc.
  Contributed by Oracle.

  This file is part of GNU Binutils.

  This program is free software; you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation; either version 3, or (at your option)
  any later version.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program; if not, write to the Free Software
  Foundation, 51 Franklin Street - Fifth Floor, Boston,
  MA 02110-1301, USA.  */

#include <errno.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <sys/ioctl.h>
#include <sys/syscall.h>
#include <linux/perf_event.h>

#include "hwcdrv.h"

/*---------------------------------------------------------------------------*/
/* macros */
#define IS_GLOBAL /* Mark global symbols */

#include "cpuid.c" /* ftns for identifying a chip */

static hdrv_pcbe_api_t hdrv_pcbe_core_api;
static hdrv_pcbe_api_t hdrv_pcbe_opteron_api;
static hdrv_pcbe_api_t *hdrv_pcbe_drivers[] = {
 &hdrv_pcbe_core_api,
 &hdrv_pcbe_opteron_api,
 NULL
};
#include "opteron_pcbe.c" /* CPU-specific code */
#include "core_pcbe.c" /* CPU-specific code  */

extern hwcdrv_api_t hwcdrv_pcl_api;
IS_GLOBAL hwcdrv_api_t *hwcdrv_drivers[] = {
 &hwcdrv_pcl_api,
 NULL
};

/*---------------------------------------------------------------------------*/

/* utils for drivers */
IS_GLOBAL int
hwcdrv_assign_all_regnos (Hwcentry* entries[], unsigned numctrs)
{
 unsigned int pmc_assigned[MAX_PICS];
 unsigned idx;
 for (int ii = 0; ii < MAX_PICS; ii++)
   pmc_assigned[ii] = 0;

 /* assign the HWCs that we already know about */
 for (idx = 0; idx < numctrs; idx++)
   {
     regno_t regno = entries[idx]->reg_num;
     if (regno == REGNO_ANY)
       {
         /* check to see if list of possible registers only contains one entry */
         regno = REG_LIST_SINGLE_VALID_ENTRY (entries[idx]->reg_list);
       }
     if (regno != REGNO_ANY)
       {
         if (regno < 0 || regno >= MAX_PICS || !regno_is_valid (entries[idx], regno))
           {
             logerr (GTXT ("For counter #%d, register %d is out of range\n"), idx + 1, regno); /*!*/
             return HWCFUNCS_ERROR_HWCARGS;
           }
         TprintfT (DBG_LT2, "hwcfuncs_assign_regnos(): preselected: idx=%d, regno=%d\n", idx, regno);
         entries[idx]->reg_num = regno; /* assigning back to entries */
         pmc_assigned[regno] = 1;
       }
   }

 /* assign HWCs that are currently REGNO_ANY */
 for (idx = 0; idx < numctrs; idx++)
   {
     if (entries[idx]->reg_num == REGNO_ANY)
       {
         int assigned = 0;
         regno_t *reg_list = entries[idx]->reg_list;
         for (; reg_list && *reg_list != REGNO_ANY; reg_list++)
           {
             regno_t regno = *reg_list;
             if (regno < 0 || regno >= MAX_PICS)
               {
                 logerr (GTXT ("For counter #%d, register %d is out of range\n"), idx + 1, regno); /*!*/
                 return HWCFUNCS_ERROR_HWCARGS;
               }
             if (pmc_assigned[regno] == 0)
               {
                 TprintfT (DBG_LT2, "hwcfuncs_assign_regnos(): assigned:   idx=%d, regno=%d\n", idx, regno);
                 entries[idx]->reg_num = regno; /* assigning back to entries */
                 pmc_assigned[regno] = 1;
                 assigned = 1;
                 break;
               }
           }
         if (!assigned)
           {
             logerr (GTXT ("Counter '%s' could not be bound to a register\n"),
                     entries[idx]->name ? entries[idx]->name : "<NULL>");
             return HWCFUNCS_ERROR_HWCARGS;
           }
       }
   }
 return 0;
}

IS_GLOBAL int
hwcdrv_lookup_cpuver (const char * cpcN_cciname)
{
 libcpc2_cpu_lookup_t *plookup;
 static libcpc2_cpu_lookup_t cpu_table[] = {
   LIBCPC2_CPU_LOOKUP_LIST
 };
 if (cpcN_cciname == NULL)
   return CPUVER_UNDEFINED;

 /* search table for name */
 for (plookup = cpu_table; plookup->cpc2_cciname; plookup++)
   {
     int n = strlen (plookup->cpc2_cciname);
     if (!strncmp (plookup->cpc2_cciname, cpcN_cciname, n))
       return plookup->cpc2_cpuver;
   }
 /* unknown, but does have a descriptive string */
 TprintfT (DBG_LT0, "hwcfuncs: CPC2: WARNING: Id of processor '%s' "
           "could not be determined\n",
           cpcN_cciname);
 return CPUVER_GENERIC;
}

/*---------------------------------------------------------------------------*/
/* utils to generate x86 register definitions on Linux */

/*
*  This code is structured as though we're going to initialize the
*  HWC by writing the Intel MSR register directly.  That is, we
*  assume the lowest 16 bits of the event number will have the event
*  and that higher bits will set attributes.
*
*  While SPARC is different, we can nonetheless use basically the
*  same "x86"-named functions:
*
*  - The event code will still be 16 bits.  It will still
*    be in the lowest 16 bits of the event number.  Though
*    perf_event_code() on SPARC will expect those bits to
*    shifted, hwcdrv_pcl.c can easily perform that shift.
*
*  - On SPARC we support only two attributes, "user" and "system",
*    which hwcdrv_pcl.c already converts to the "exclude_user"
*    and "exclude_kernel" fields expected by perf_event_open().
*    "user" and "system" are stored in event bits 16 and 17.
*    For M8, a 4-bit mask of supported PICs is stored in bits [23:20].
*/

IS_GLOBAL hwcdrv_get_eventnum_fn_t *hwcdrv_get_x86_eventnum = 0;

static const attr_info_t perfctr_sparc_attrs[] = {
 {NTXT ("user"),   0, 0x01, 16}, //usr
 {NTXT ("system"), 0, 0x01, 17}, //os
 {NULL, 0, 0x00, 0},
};
static const attr_info_t perfctr_x64_attrs[] = {/* ok for Core2 & later */
 {NTXT ("umask"),  0, 0xff, 8},
 {NTXT ("user"),   0, 0x01, 16}, //usr
 //{NTXT("nouser"),  1, 0x01, 16}, //usr (inverted)
 {NTXT ("system"), 0, 0x01, 17}, //os
 {NTXT ("edge"),   0, 0x01, 18},
 {NTXT ("pc"),     0, 0x01, 19},
 {NTXT ("inv"),    0, 0x01, 23},
 {NTXT ("cmask"),  0, 0xff, 24},
 {NULL, 0, 0x00, 0},
};
const attr_info_t *perfctr_attrs_table = perfctr_x64_attrs;

static const eventsel_t perfctr_evntsel_enable_bits = (0x01 << 16) | /* usr */
   // (0xff <<  0) |   /* event*/
   // (0xff <<  8) |   /* umask */
   // (0x01 << 17) |   /* os */
   // (0x01 << 18) |   /* edge */
   // (0x01 << 19) |   /* pc */
   (0x01 << 20) |      /* int */
   // (0x01 << 21) |   /* reserved */
   (0x01 << 22) |      /* enable */
   // (0x01 << 23) |   /* inv */
   // (0xff << 24) |   /* cmask */
   0;

static int
myperfctr_get_x86_eventnum (const char *eventname, uint_t pmc,
                           eventsel_t *eventsel, eventsel_t *valid_umask,
                           uint_t *pmc_sel)
{
 if (hwcdrv_get_x86_eventnum &&
     !hwcdrv_get_x86_eventnum (eventname, pmc, eventsel, valid_umask, pmc_sel))
   return 0;

 /* check for numerically-specified counters */
 char * endptr;
 uint64_t num = strtoull (eventname, &endptr, 0);
 if (*eventname && !*endptr)
   {
     *eventsel = EXTENDED_EVNUM_2_EVSEL (num);
     *valid_umask = 0xff; /* allow any umask (unused for SPARC?) */
     *pmc_sel = pmc;
     return 0;
   }

 /* name does not specify a numeric value */
 *eventsel = (eventsel_t) - 1;
 *valid_umask = 0x0;
 *pmc_sel = pmc;
 return -1;
}

static int
mask_shift_set (eventsel_t *presult, eventsel_t invalue,
               eventsel_t mask, eventsel_t shift)
{
 if (invalue & ~mask)
   return -1; /* invalue attempts to set bits outside of mask */
 *presult &= ~(mask << shift); /* clear all the mask bits */
 *presult |= (invalue << shift); /* set bits according to invalue */
 return 0;
}

static int
set_x86_attr_bits (eventsel_t *result_mask, eventsel_t evnt_valid_umask,
                  hwcfuncs_attr_t attrs[], int nattrs, const char*nameOnly)
{
 eventsel_t evntsel = *result_mask;
 for (int ii = 0; ii < (int) nattrs; ii++)
   {
     const char *attrname = attrs[ii].ca_name;
     eventsel_t attrval = (eventsel_t) attrs[ii].ca_val;
     const char *tmpname;
     int attr_found = 0;
     for (int jj = 0; (tmpname = perfctr_attrs_table[jj].attrname); jj++)
       {
         if (strcmp (attrname, tmpname) == 0)
           {
             if (strcmp (attrname, "umask") == 0)
               {
                 if (attrval & ~evnt_valid_umask)
                   {
                     logerr (GTXT ("for `%s', allowable umask bits are: 0x%llx\n"),
                             nameOnly, (long long) evnt_valid_umask);
                     return -1;
                   }
               }
             if (mask_shift_set (&evntsel,
                                 perfctr_attrs_table[jj].is_inverted ? (attrval^1) : attrval,
                                 perfctr_attrs_table[jj].mask,
                                 perfctr_attrs_table[jj].shift))
               {
                 logerr (GTXT ("`%s' attribute `%s' could not be set to 0x%llx\n"),
                         nameOnly, attrname, (long long) attrval);
                 return -1;
               }
             TprintfT (DBG_LT2, "hwcfuncs: Counter %s, attribute %s set to 0x%llx\n",
                       nameOnly, attrname, (long long) attrval);
             attr_found = 1;
             break;
           }
       }
     if (!attr_found)
       {
         logerr (GTXT ("attribute `%s' is invalid\n"), attrname);
         return -1;
       }
   }
 *result_mask = evntsel;
 return 0;
}

IS_GLOBAL int
hwcfuncs_get_x86_eventsel (unsigned int regno, const char *int_name,
                          eventsel_t *return_event, uint_t *return_pmc_sel)
{
 hwcfuncs_attr_t attrs[HWCFUNCS_MAX_ATTRS + 1];
 unsigned nattrs = 0;
 char *nameOnly = NULL;
 eventsel_t evntsel = 0; // event number
 eventsel_t evnt_valid_umask = 0;
 uint_t pmc_sel = 0;
 int rc = -1;
 *return_event = 0;
 *return_pmc_sel = 0;
 void *attr_mem = hwcfuncs_parse_attrs (int_name, attrs, HWCFUNCS_MAX_ATTRS,
                                  &nattrs, NULL);
 if (!attr_mem)
   {
     logerr (GTXT ("out of memory, could not parse attributes\n"));
     return -1;
   }
 hwcfuncs_parse_ctr (int_name, NULL, &nameOnly, NULL, NULL, NULL);
 if (regno == REGNO_ANY)
   {
     logerr (GTXT ("reg# could not be determined for `%s'\n"), nameOnly);
     goto attr_wrapup;
   }

 /* look up evntsel */
 if (myperfctr_get_x86_eventnum (nameOnly, regno,
                                 &evntsel, &evnt_valid_umask, &pmc_sel))
   {
     logerr (GTXT ("counter `%s' is not valid\n"), nameOnly);
     goto attr_wrapup;
   }
 TprintfT (DBG_LT1, "hwcfuncs: event=0x%llx pmc=0x%x '%s' nattrs = %u\n",
           (long long) evntsel, pmc_sel, nameOnly, nattrs);

 /* determine event attributes */
 eventsel_t evnt_attrs = perfctr_evntsel_enable_bits;
 if (set_x86_attr_bits (&evnt_attrs, evnt_valid_umask, attrs, nattrs, nameOnly))
   goto attr_wrapup;
 if (evntsel & evnt_attrs)
   TprintfT (DBG_LT0, "hwcfuncs: ERROR - evntsel & enable bits overlap: 0x%llx 0x%llx 0x%llx\n",
             (long long) evntsel, (long long) evnt_attrs,
             (long long) (evntsel & evnt_attrs));
 *return_event = evntsel | evnt_attrs;
 *return_pmc_sel = pmc_sel;
 rc = 0;

attr_wrapup:
 free (attr_mem);
 free (nameOnly);
 return rc;
}

#ifdef __x86_64__
#define syscall_instr          "syscall"
#define syscall_clobber        "rcx", "r11", "memory"
#endif
#ifdef __i386__
#define syscall_instr          "int $0x80"
#define syscall_clobber        "memory"
#endif

static inline int
perf_event_open (struct perf_event_attr *hw_event_uptr, pid_t pid,
                int cpu, int group_fd, unsigned long flags)
{
 /* It seems that perf_event_open() sometimes fails spuriously,
  * even while an immediate retry succeeds.
  * So, let's try a few retries if the call fails just to be sure.
  */
 int rc;
 for (int retry = 0; retry < 5; retry++)
   {
     rc = syscall (__NR_perf_event_open, hw_event_uptr, pid, cpu, group_fd, flags);
     if (rc != -1)
       return rc;
   }
 return rc;
}

/*---------------------------------------------------------------------------*/
/* macros & fwd prototypes */

#define HWCDRV_API      static /* Mark functions used by hwcdrv API */

HWCDRV_API int hwcdrv_start (void);
HWCDRV_API int hwcdrv_free_counters ();

static pid_t
hwcdrv_gettid (void)
{
#ifndef LIBCOLLECTOR_SRC
 return syscall (__NR_gettid);
#elif defined(intel)
 pid_t r;
 __asm__ __volatile__(syscall_instr
                      : "=a" (r) : "0" (__NR_gettid)
                      : syscall_clobber);
 return r;
#else
 return syscall (__NR_gettid); // FIXUP_XXX_SPARC_LINUX // write gettid in asm
#endif
}

/*---------------------------------------------------------------------------*/
/* types */

#define NPAGES_PER_BUF  1 // number of pages to be used for perf_event samples
// must be a power of 2

/*---------------------------------------------------------------------------*/

/* typedefs */

typedef struct
{ // event (hwc) definition
 unsigned int reg_num; // PMC assignment, potentially for detecting conflicts
 eventsel_t eventsel;          // raw event bits (Intel/AMD)
 uint64_t counter_preload;     // number of HWC events before signal
 struct perf_event_attr hw;    // perf_event definition
 hrtime_t min_time;            // minimum time we're targeting between events
 char *name;
} perf_event_def_t;

typedef struct
{ // runtime state of perf_event buffer
 void *buf;                    // pointer to mmapped buffer
 size_t pagesz;                // size of pages
} buffer_state_t;

typedef struct
{ // runtime state of counter values
 uint64_t prev_ena_ts;         // previous perf_event "enabled" time
 uint64_t prev_run_ts;         // previous perf_event "running" time
 uint64_t prev_value;          // previous HWC value
} counter_value_state_t;

typedef struct
{ // per-counter information
 perf_event_def_t *ev_def;     // global HWC definition for one counter
 int fd;                       // perf_event fd
 buffer_state_t buf_state;     // perf_event buffer's state
 counter_value_state_t value_state; // counter state
 int needs_restart;            // workaround for dbx failure to preserve si_fd
 uint64_t last_overflow_period;
 hrtime_t last_overflow_time;
} counter_state_t;

typedef struct
{ // per-thread context
 counter_state_t *ctr_list;
 int signal_fd;                // fd that caused the most recent signal
 pid_t tid;                    // for debugging signal delivery problems
} hdrv_pcl_ctx_t;

/*---------------------------------------------------------------------------*/

/* static variables */
static struct
{
 int library_ok;
 int internal_open_called;
 hwcfuncs_tsd_get_fn_t find_vpc_ctx;
 unsigned hwcdef_cnt;      /* number of *active* hardware counters */
 hwcdrv_get_events_fn_t *get_events;
} hdrv_pcl_state;

static hwcdrv_about_t hdrv_pcl_about = {.cpcN_cpuver = CPUVER_UNDEFINED};
static perf_event_def_t global_perf_event_def[MAX_PICS];

#define COUNTERS_ENABLED()      (hdrv_pcl_state.hwcdef_cnt)


/* perf_event buffer formatting and handling */
static void
reset_buf (buffer_state_t *bufstate)
{
 TprintfT (0, "hwcdrv: ERROR: perf_event reset_buf() called!\n");
 struct perf_event_mmap_page *metadata = bufstate->buf;
 if (metadata)
   metadata->data_tail = metadata->data_head;
}

static int
skip_buf (buffer_state_t *bufstate, size_t sz)
{
 TprintfT (DBG_LT1, "hwcdrv: WARNING: perf_event skip_buf called!\n");
 struct perf_event_mmap_page *metadata = bufstate->buf;
 if (metadata == NULL)
   return -1;
 size_t pgsz = bufstate->pagesz;
 size_t bufsz = NPAGES_PER_BUF*pgsz;
 uint64_t d_tail = metadata->data_tail;
 uint64_t d_head = metadata->data_head;

 // validate request size
 if (sz > d_head - d_tail || sz >= bufsz)
   {
     reset_buf (bufstate);
     return -1;
   }
 metadata->data_tail = d_tail + sz; // advance tail
 return 0;
}

static int
read_buf (buffer_state_t *bufstate, void *buf, size_t sz)
{
 struct perf_event_mmap_page *metadata = bufstate->buf;
 if (metadata == NULL)
   return -1;
 size_t pgsz = bufstate->pagesz;
 size_t bufsz = NPAGES_PER_BUF*pgsz;
 uint64_t d_tail = metadata->data_tail;
 uint64_t d_head = metadata->data_head;

 // validate request size
 if (sz > d_head - d_tail || sz >= bufsz)
   {
     reset_buf (bufstate);
     return -1;
   }
 char *buf_base = ((char *) metadata) + pgsz; // start of data buffer
 uint64_t start_pos = d_tail & (bufsz - 1); // char offset into data buffer
 size_t nbytes = sz;
 if (start_pos + sz > bufsz)
   {
     // will wrap past end of buffer
     nbytes = bufsz - start_pos;
     memcpy (buf, buf_base + start_pos, nbytes);
     start_pos = 0; // wrap to start
     buf = (void *) (((char *) buf) + nbytes);
     nbytes = sz - nbytes;
   }
 memcpy (buf, buf_base + start_pos, nbytes);
 metadata->data_tail += sz;
 return 0;
}

static int
read_u64 (buffer_state_t *bufstate, uint64_t *value)
{
 return read_buf (bufstate, value, sizeof (uint64_t));
}

static int
read_sample (counter_state_t *ctr_state, int msgsz, uint64_t *rvalue,
            uint64_t *rlost)
{
 // returns count of bytes read
 buffer_state_t *bufstate = &ctr_state->buf_state;
 counter_value_state_t *cntstate = &ctr_state->value_state;
 int readsz = 0;

 // PERF_SAMPLE_IP
 uint64_t ipc = 0;
 int rc = read_u64 (bufstate, &ipc);
 if (rc)
   return -1;
 readsz += sizeof (uint64_t);

 // PERF_SAMPLE_READ: value
 uint64_t value = 0;
 rc = read_u64 (bufstate, &value);
 if (rc)
   return -2;
 readsz += sizeof (uint64_t);

 /* Bug 20806896
  * Old Linux kernels (e.g. 2.6.32) on certain systems return enabled and
  * running times in the sample data that correspond to the metadata times
  *     metadata->time_enabled
  *     metadata->time_running
  * from the PREVIOUS (not current) sample.  Probably just ignore this bug
  * since it's on old kernels and we only use the enabled and running times
  * to construct loss_estimate.
  */
 // PERF_SAMPLE_READ: PERF_FORMAT_ENABLED
 uint64_t enabled_time = 0;
 rc = read_u64 (bufstate, &enabled_time);
 if (rc)
   return -3;
 readsz += sizeof (uint64_t);

 // PERF_SAMPLE_READ: PERF_FORMAT_RUNNING
 uint64_t running_time = 0;
 rc = read_u64 (bufstate, &running_time);
 if (rc)
   return -4;
 readsz += sizeof (uint64_t);

 uint64_t value_delta = value - cntstate->prev_value;
 uint64_t enabled_delta = enabled_time - cntstate->prev_ena_ts;
 uint64_t running_delta = running_time - cntstate->prev_run_ts;
 cntstate->prev_value = value;
 cntstate->prev_ena_ts = enabled_time;
 cntstate->prev_run_ts = running_time;

 // 24830461 need workaround for Linux anomalous HWC skid overrun
 int set_error_flag = 0;
 if (value_delta > 2 * ctr_state->last_overflow_period + 2000 /* HWC_SKID_TOLERANCE */)
   set_error_flag = 1;

 uint64_t loss_estimate = 0; // estimate loss of events caused by multiplexing
 if (running_delta == enabled_delta)
   {
     // counter was running 100% of time, no multiplexing
   }
 else if (running_delta == 0)
   loss_estimate = 1; // token amount to aid in debugging perfctr oddities
 else if ((running_delta > enabled_delta) || (enabled_delta & 0x1000000000000000ll))
   {
     // running should be smaller than enabled, can't estimate
     /*
      * 21418391 HWC can have a negative count
      *
      * We've also seen enabled not only be smaller than running
      * but in fact go negative.  Guard against this.
      */
     loss_estimate = 2; // token amount to aid in debugging perfctr oddities
   }
 else
   {
     // counter was running less than 100% of time
     // Example: ena=7772268 run=6775669 raw_value=316004 scaled_value=362483 loss_est=46479
     uint64_t scaled_delta = (double) value_delta * enabled_delta / running_delta;
     value_delta = scaled_delta;
#if 0
     // We should perhaps warn the user that multiplexing is going on,
     // but hwcdrv_pcl.c doesn't know about the collector_interface, SP_JCMD_COMMENT, or COL_COMMENT_* values.
     // For now we simply don't report.
     // Perhaps we should address the issue not here but in the caller collector_sigemt_handler(),
     // but at that level "lost" has a meaning that's considerably broader than just multiplexing.
     collector_interface->writeLog ("<event kind=\"%s\" id=\"%d\">%s %d -> %d</event>\n",
                                    SP_JCMD_COMMENT, COL_COMMENT_HWCADJ, global_perf_event_def[idx].name,
                                    ctr_list[idx].last_overflow_period, new_period);
#endif
   }
 TprintfT ((loss_estimate || set_error_flag) ? DBG_LT1 : DBG_LT3,
           "hwcdrv: '%s' ipc=0x%llx ena=%llu run=%llu "
           "value_delta=%lld(0x%llx) loss_est=%llu %s error_flag='%s'\n",
           ctr_state->ev_def->name, (long long) ipc,
           (long long) enabled_delta, (long long) running_delta,
           (long long) value_delta, (long long) value_delta,
           (unsigned long long) loss_estimate,
           loss_estimate ? ", WARNING - SCALED" : "",
           set_error_flag ? ", ERRORFLAG" : "");
 if (set_error_flag == 1)
   value_delta |= (1ULL << 63)     /* HWCVAL_ERR_FLAG */;
 *rvalue = value_delta;
 *rlost = loss_estimate;
 if (readsz != msgsz)
   {
     TprintfT (0, "hwcdrv: ERROR: perf_event sample not fully parsed\n");
     return -5;
   }
 return 0;
}

static void
dump_perf_event_attr (struct perf_event_attr *at)
{
 TprintfT (DBG_LT2, "dump_perf_event_attr:  size=%d  type=%d  sample_period=%lld\n"
           "  config=0x%llx  config1=0x%llx  config2=0x%llx  wakeup_events=%lld __reserved_1=%lld\n",
           (int) at->size, (int) at->type, (unsigned long long) at->sample_period,
           (unsigned long long) at->config, (unsigned long long) at->config1,
           (unsigned long long) at->config2, (unsigned long long) at->wakeup_events,
           (unsigned long long) at->__reserved_1);
#define DUMP_F(fld) if (at->fld) TprintfT(DBG_LT2, "  %-10s : %lld\n", #fld, (long long) at->fld)
 DUMP_F (disabled);
 DUMP_F (inherit);
 DUMP_F (pinned);
 DUMP_F (exclusive);
 DUMP_F (exclude_user);
 DUMP_F (exclude_kernel);
 DUMP_F (exclude_hv);
 DUMP_F (exclude_idle);
 //    DUMP_F(xmmap);
 DUMP_F (comm);
 DUMP_F (freq);
 DUMP_F (inherit_stat);
 DUMP_F (enable_on_exec);
 DUMP_F (task);
 DUMP_F (watermark);
}

static void
init_perf_event (struct perf_event_attr *hw, uint64_t event, uint64_t period,
                Hwcentry *hwce)
{
 memset (hw, 0, sizeof (struct perf_event_attr));
 hw->size = sizeof (struct perf_event_attr);
 if (hwce && hwce->use_perf_event_type)
   {
     hw->config = hwce->config;
     hw->type = hwce->type;
   }
 else
   { // backward compatibility. The old interface had no 'hwce' argument.
     hw->config = event;
     hw->type = PERF_TYPE_RAW; // hw/sw/trace/raw...
   }
 hw->sample_period = period;
 hw->sample_type = PERF_SAMPLE_IP |
         // PERF_SAMPLE_TID            |
         // PERF_SAMPLE_TIME           | // possibly interesting
         // PERF_SAMPLE_ADDR           |
         PERF_SAMPLE_READ | // HWC value
         // PERF_SAMPLE_CALLCHAIN      | // interesting
         // PERF_SAMPLE_ID             |
         // PERF_SAMPLE_CPU            | // possibly interesting
         // PERF_SAMPLE_PERIOD         |
         // PERF_SAMPLE_STREAM_ID      |
         // PERF_SAMPLE_RAW            |
         0;
 hw->read_format =
         PERF_FORMAT_TOTAL_TIME_ENABLED | // detect when hwc not scheduled
         PERF_FORMAT_TOTAL_TIME_RUNNING | // detect when hwc not scheduled
         // PERF_FORMAT_ID             |
         // PERF_FORMAT_GROUP          |
         0;
 hw->disabled = 1; /* off by default */

 // Note: the following override config.priv bits!
 hw->exclude_user = (event & (1 << 16)) == 0;      /* don't count user */
 hw->exclude_kernel = (event & (1 << 17)) == 0;    /* ditto kernel */
 hw->exclude_hv = 1;       /* ditto hypervisor */
 hw->wakeup_events = 1;    /* wakeup every n events */
 dump_perf_event_attr (hw);
}

static int
start_one_ctr (int ii, size_t pgsz, hdrv_pcl_ctx_t * pctx, char *error_string)
{
 // pe_attr should have been initialized in hwcdrv_create_counters()
 struct perf_event_attr pe_attr;
 memcpy (&pe_attr, &global_perf_event_def[ii].hw, sizeof (pe_attr));

 // but we adjust the period, so make sure that pctx->ctr_list[ii].last_overflow_period has been set
 pe_attr.sample_period = pctx->ctr_list[ii].last_overflow_period;

 int hwc_fd = perf_event_open (&pe_attr, pctx->tid, -1, -1, 0);
 if (hwc_fd == -1)
   {
     TprintfT (DBG_LT1, "%s idx=%d perf_event_open failed, errno=%d\n",
               error_string, ii, errno);
     return 1;
   }

 size_t buffer_area_sz = (NPAGES_PER_BUF + 1) * pgsz; // add a page for metadata
 void * buf = mmap (NULL, buffer_area_sz, //YXXX is this a safe call?
                    PROT_READ | PROT_WRITE, MAP_SHARED, hwc_fd, 0);
 if (buf == MAP_FAILED)
   {
     TprintfT (0, "sz = %ld, pgsz = %ld\n  err=%s idx=%d mmap failed: %s\n",
               (long) buffer_area_sz, (long) pgsz, error_string, ii, strerror (errno));
     return 1;
   }
 pctx->ctr_list[ii].ev_def = &global_perf_event_def[ii]; // why do we set ev_def?  we never seem to use it
 pctx->ctr_list[ii].fd = hwc_fd;
 pctx->ctr_list[ii].buf_state.buf = buf;
 pctx->ctr_list[ii].buf_state.pagesz = pgsz;
 pctx->ctr_list[ii].value_state.prev_ena_ts = 0;
 pctx->ctr_list[ii].value_state.prev_run_ts = 0;
 pctx->ctr_list[ii].value_state.prev_value = 0;
 pctx->ctr_list[ii].last_overflow_time = gethrtime ();

 /* set async mode */
 long flags = fcntl (hwc_fd, F_GETFL, 0) | O_ASYNC;
 int rc = fcntl (hwc_fd, F_SETFL, flags);
 if (rc == -1)
   {
     TprintfT (0, "%s idx=%d O_ASYNC failed\n", error_string, ii);
     return 1;
   }

 /*
  * set lwp ownership of the fd
  * See BUGS section of "man perf_event_open":
  *     The F_SETOWN_EX option to fcntl(2) is needed to properly get
  *     overflow signals in threads.  This was introduced in Linux 2.6.32.
  * Legacy references:
  *     see http://lkml.org/lkml/2009/8/4/128
  *     google man fcntl F_SETOWN_EX -conflict
  *       "From Linux 2.6.32 onward, use F_SETOWN_EX to target
  *       SIGIO and SIGURG signals at a particular thread."
  *     http://icl.cs.utk.edu/papi/docs/da/d2a/examples__v2_8x_2self__smpl__multi_8c.html
  *     See 2010 CSCADS presentation by Eranian
  */
 struct f_owner_ex fowner_ex;
 fowner_ex.type = F_OWNER_TID;
 fowner_ex.pid = pctx->tid;
 rc = fcntl (hwc_fd, F_SETOWN_EX, (unsigned long) &fowner_ex);
 if (rc == -1)
   {
     TprintfT (0, "%s idx=%d F_SETOWN failed\n", error_string, ii);
     return 1;
   }

 /* Use sigio so handler can determine FD via siginfo->si_fd. */
 rc = fcntl (hwc_fd, F_SETSIG, SIGIO);
 if (rc == -1)
   {
     TprintfT (0, "%s idx=%d F_SETSIG failed\n", error_string, ii);
     return 1;
   }
 return 0;
}

static int
stop_one_ctr (int ii, counter_state_t *ctr_list)
{
 int hwc_rc = 0;
 if (-1 == ioctl (ctr_list[ii].fd, PERF_EVENT_IOC_DISABLE, 1))
   {
     TprintfT (0, "hwcdrv: ERROR: PERF_EVENT_IOC_DISABLE #%d failed: errno=%d\n", ii, errno);
     hwc_rc = HWCFUNCS_ERROR_GENERIC;
   }
 void *buf = ctr_list[ii].buf_state.buf;
 if (buf)
   {
     size_t bufsz = (NPAGES_PER_BUF + 1) * ctr_list[ii].buf_state.pagesz;
     ctr_list[ii].buf_state.buf = NULL;
     int tmprc = munmap (buf, bufsz);
     if (tmprc)
       {
         TprintfT (0, "hwcdrv: ERROR: munmap() #%d failed: errno=%d\n", ii, errno);
         hwc_rc = HWCFUNCS_ERROR_GENERIC;
       }
   }
 if (-1 == close (ctr_list[ii].fd))
   {
     TprintfT (0, "hwcdrv: ERROR: close(fd) #%d failed: errno=%d\n", ii, errno);
     hwc_rc = HWCFUNCS_ERROR_GENERIC;
   }
 return hwc_rc;
}

/* HWCDRV_API for thread-specific actions */
HWCDRV_API int
hwcdrv_lwp_init (void)
{
 return hwcdrv_start ();
}

HWCDRV_API void
hwcdrv_lwp_fini (void)
{
 hwcdrv_free_counters ();  /* also sets pctx->ctr_list=NULL; */
}

/* open */
static int
hdrv_pcl_internal_open ()
{
 if (hdrv_pcl_state.internal_open_called)
   {
     TprintfT (0, "hwcdrv: WARNING: hdrv_pcl_internal_open: already called\n");
     return HWCFUNCS_ERROR_ALREADY_CALLED;
   }

 // determine if PCL is available
 perf_event_def_t tmp_event_def;
 memset (&tmp_event_def, 0, sizeof (tmp_event_def));
 struct perf_event_attr *pe_attr = &tmp_event_def.hw;
 init_perf_event (pe_attr, 0, 0, NULL);
 pe_attr->type = PERF_TYPE_HARDWARE; // specify abstracted HW event
 pe_attr->config = PERF_COUNT_HW_INSTRUCTIONS; // specify abstracted insts
 int hwc_fd = perf_event_open (pe_attr,
                               0, // pid/tid, 0 is self
                               -1, // cpu, -1 is per-thread mode
                               -1, // group_fd, -1 is root
                               0); // flags
 if (hwc_fd == -1)
   {
     TprintfT (DBG_LT1, "hwcdrv: WARNING: hdrv_pcl_internal_open:"
               " perf_event_open() failed, errno=%d\n", errno);
     goto internal_open_error;
   }

 /* see if the PCL is new enough to know about F_SETOWN_EX */
 struct f_owner_ex fowner_ex;
 fowner_ex.type = F_OWNER_TID;
 fowner_ex.pid = hwcdrv_gettid (); // "pid=tid" is correct w/F_OWNER_TID
 if (fcntl (hwc_fd, F_SETOWN_EX, (unsigned long) &fowner_ex) == -1)
   {
     TprintfT (DBG_LT1, "hwcdrv: WARNING: hdrv_pcl_internal_open: "
               "F_SETOWN failed, errno=%d\n", errno);
     close (hwc_fd);
     goto internal_open_error;
   }
 close (hwc_fd);

 hdrv_pcl_state.internal_open_called = 1;
 hdrv_pcl_state.library_ok = 1; // set to non-zero to show it's initted
 hdrv_pcl_about.cpcN_cpuver = CPUVER_UNDEFINED;
 TprintfT (DBG_LT2, "hwcdrv: hdrv_pcl_internal_open()\n");
 for (int ii = 0; hdrv_pcbe_drivers[ii]; ii++)
   {
     hdrv_pcbe_api_t *ppcbe = hdrv_pcbe_drivers[ii];
     if (!ppcbe->hdrv_pcbe_init ())
       {
         hdrv_pcl_about.cpcN_cciname = ppcbe->hdrv_pcbe_impl_name ();
         hdrv_pcl_about.cpcN_cpuver = hwcdrv_lookup_cpuver (hdrv_pcl_about.cpcN_cciname);
         if (hdrv_pcl_about.cpcN_cpuver == CPUVER_UNDEFINED)
           goto internal_open_error;
         hdrv_pcl_about.cpcN_npics = ppcbe->hdrv_pcbe_ncounters ();
         hdrv_pcl_about.cpcN_docref = ppcbe->hdrv_pcbe_cpuref ();
         hdrv_pcl_state.get_events = ppcbe->hdrv_pcbe_get_events;
         hwcdrv_get_x86_eventnum = ppcbe->hdrv_pcbe_get_eventnum;
         break;
       }
   }
 if (hdrv_pcl_about.cpcN_npics > MAX_PICS)
   {
     TprintfT (0, "hwcdrv: WARNING: hdrv_pcl_internal_open:"
               " reducing number of HWCs from %u to %u on processor '%s'\n",
               hdrv_pcl_about.cpcN_npics, MAX_PICS, hdrv_pcl_about.cpcN_cciname);
     hdrv_pcl_about.cpcN_npics = MAX_PICS;
   }
 TprintfT (DBG_LT1, "hwcdrv: hdrv_pcl_internal_open:"
           " perf_event cpuver=%d, name='%s'\n",
           hdrv_pcl_about.cpcN_cpuver, hdrv_pcl_about.cpcN_cciname);
 return 0;

internal_open_error:
 hdrv_pcl_about.cpcN_cpuver = CPUVER_UNDEFINED;
 hdrv_pcl_about.cpcN_npics = 0;
 hdrv_pcl_about.cpcN_docref = NULL;
 hdrv_pcl_about.cpcN_cciname = NULL;
 return HWCFUNCS_ERROR_NOT_SUPPORTED;
}

static void *
single_thread_tsd_ftn ()
{
 static hdrv_pcl_ctx_t tsd_context;
 return &tsd_context;
}

/* HWCDRV_API */
HWCDRV_API int
hwcdrv_init (hwcfuncs_abort_fn_t abort_ftn, int *tsd_sz)
{
 hdrv_pcl_state.find_vpc_ctx = single_thread_tsd_ftn;
 if (tsd_sz)
   *tsd_sz = sizeof (hdrv_pcl_ctx_t);

 if (hdrv_pcl_state.internal_open_called)
   return HWCFUNCS_ERROR_ALREADY_CALLED;
 return hdrv_pcl_internal_open ();
}

HWCDRV_API void
hwcdrv_get_info (int *cpuver, const char **cciname, uint_t *npics,
                const char **docref, uint64_t *support)
{
 if (cpuver)
   *cpuver = hdrv_pcl_about.cpcN_cpuver;
 if (cciname)
   *cciname = hdrv_pcl_about.cpcN_cciname;
 if (npics)
   *npics = hdrv_pcl_about.cpcN_npics;
 if (docref)
   *docref = hdrv_pcl_about.cpcN_docref;
 if (support)
   *support = HWCFUNCS_SUPPORT_OVERFLOW_PROFILING | HWCFUNCS_SUPPORT_OVERFLOW_CTR_ID;
}

HWCDRV_API int
hwcdrv_enable_mt (hwcfuncs_tsd_get_fn_t tsd_ftn)
{
 if (tsd_ftn)
   hdrv_pcl_state.find_vpc_ctx = tsd_ftn;
 else
   {
     TprintfT (0, "hwcdrv: ERROR: enable_mt(): tsd_ftn==NULL\n");
     return HWCFUNCS_ERROR_UNAVAIL;
   }
 return 0;
}

HWCDRV_API int
hwcdrv_get_descriptions (hwcf_hwc_cb_t *hwc_cb, hwcf_attr_cb_t *attr_cb)
{
 int count = 0;
 if (hwc_cb && hdrv_pcl_state.get_events)
   count = hdrv_pcl_state.get_events (hwc_cb);
 if (attr_cb)
   for (int ii = 0; perfctr_attrs_table && perfctr_attrs_table[ii].attrname; ii++)
     attr_cb (perfctr_attrs_table[ii].attrname);
 if (!count)
   return -1;
 return 0;
}

HWCDRV_API int
hwcdrv_assign_regnos (Hwcentry* entries[], unsigned numctrs)
{
 return hwcdrv_assign_all_regnos (entries, numctrs);
}

static int
internal_hwc_start (int fd)
{
 int rc = ioctl (fd, PERF_EVENT_IOC_REFRESH, 1);
 if (rc == -1)
   {
     TprintfT (DBG_LT0, "hwcdrv: ERROR: internal_hwc_start:"
               " PERF_EVENT_IOC_REFRESH(fd=%d) failed: errno=%d\n", fd, errno);
     return HWCFUNCS_ERROR_UNAVAIL;
   }
 TprintfT (DBG_LT3, "hwcdrv: internal_hwc_start(fd=%d)\n", fd);
 return 0;
}

HWCDRV_API int
hwcdrv_overflow (siginfo_t *si, hwc_event_t *eventp, hwc_event_t *lost_events)
{
 /* set expired counters to overflow value and all others to 0 */
 /* return 0: OK, counters should be restarted */
 /* return non-zero: eventp not set, counters should not be restarted */
 /* clear return values */
 int ii;
 for (ii = 0; ii < hdrv_pcl_state.hwcdef_cnt; ii++)
   {
     eventp->ce_pic[ii] = 0;
     lost_events->ce_pic[ii] = 0;
   }
 hrtime_t sig_ts = gethrtime (); //YXXX get this from HWC event?
 eventp->ce_hrt = sig_ts;
 lost_events->ce_hrt = sig_ts;

 /* determine source signal */
 int signal_fd = -1;
 switch (si->si_code)
   {
   case POLL_HUP: /* expected value from pcl */
     /* According to Stephane Eranian:
      * "expect POLL_HUP instead of POLL_IN because we are
      * in one-shot mode (IOC_REFRESH)"
      */
     signal_fd = si->si_fd;
     break;
   case SI_TKILL: /* event forwarded by tkill */
     /* DBX can only forward SI_TKILL when it detects POLL_HUP
      * unfortunately, this means that si->si_fd has been lost...
      * We need to process the buffers, but we don't know the fd!
      */
     TprintfT (DBG_LT0, "hwcdrv: sig_ts=%llu: WARNING: hwcdrv_overflow:"
               " SI_TKILL detected\n", sig_ts);
     break;
   default:
     // "sometimes we see a POLL_IN (1) with very high event rates,"
     // according to eranian(?)
     TprintfT (DBG_LT0, "hwcdrv: sig_ts=%llu: ERROR: hwcdrv_overflow:"
               " unexpected si_code 0x%x\n", sig_ts, si->si_code);
     return HWCFUNCS_ERROR_GENERIC;
   }

 hdrv_pcl_ctx_t * pctx = hdrv_pcl_state.find_vpc_ctx ();
 if (!pctx)
   {
     TprintfT (DBG_LT0, "hwcdrv: sig_ts=%llu: ERROR: hwcdrv_overflow:"
               " tsd context is NULL\n", sig_ts);
     return HWCFUNCS_ERROR_UNEXPECTED;
   }
 counter_state_t * ctr_list = (counter_state_t *) pctx->ctr_list;
 if (!ctr_list)
   {
     TprintfT (DBG_LT0, "hwcdrv: sig_ts=%llu: WARNING: hwcdrv_overflow:"
               " ctr_list is NULL\n", sig_ts);
     return HWCFUNCS_ERROR_UNEXPECTED;
   }

 /* clear needs_restart flag */
 for (ii = 0; ii < hdrv_pcl_state.hwcdef_cnt; ii++)
   ctr_list[ii].needs_restart = 0;

 /* attempt to identify the counter to read */
 int signal_idx = -1;
 pctx->signal_fd = signal_fd; // save the signal provided by siginfo_t
 if (signal_fd != -1)
   {
     for (ii = 0; ii < hdrv_pcl_state.hwcdef_cnt; ii++)
       {
         if (ctr_list[ii].fd == signal_fd)
           {
             signal_idx = ii;
             break;
           }
       }
   }

 if (signal_idx < 0)
   {
     TprintfT (DBG_LT0, "hwcdrv: sig_ts=%llu: ERROR: hwcdrv_overflow:"
               " pmc not determined!\n", sig_ts);
     lost_events->ce_pic[0] = 1; /* record a bogus value into experiment */
     // note: bogus value may get overwritten in loop below
   }

 /* capture sample(s).  In addition to signal_idx, check other counters. */
 struct perf_event_header sheader;
 int idx;
 for (idx = 0; idx < hdrv_pcl_state.hwcdef_cnt; idx++)
   {
     int num_recs = 0;
     while (1)
       {
         /* check for samples */
         struct perf_event_mmap_page *metadata = ctr_list[idx].buf_state.buf;
         if (metadata == NULL)
           break; // empty
         if (metadata->data_tail == metadata->data_head)
           break; // empty

         /* read header */
         if (read_buf (&ctr_list[idx].buf_state, &sheader, sizeof (sheader)))
           break;
         num_recs++;

         /* check for PERF_RECORD_SAMPLE */
         size_t datasz = sheader.size - sizeof (struct perf_event_header);
         if (sheader.type != PERF_RECORD_SAMPLE)
           {
             TprintfT (DBG_LT2, "hwcdrv: sig_ts=%llu: WARNING: hwcdrv_overflow:"
                       " unexpected recd type=%d\n",
                       sig_ts, sheader.type);
             if (skip_buf (&ctr_list[idx].buf_state, datasz))
               {
                 TprintfT (DBG_LT0, "hwcdrv: sig_ts=%llu: ERROR: hwcdrv_overflow:"
                           " skip recd type=%d failed\n", sig_ts, sheader.type);
                 lost_events->ce_pic[idx] = 4; /* record a bogus value */
                 break; // failed to skip buffer??
               }
             lost_events->ce_pic[idx] = 2; /* record a bogus value */
             continue; // advance to next record
           }

         /* type is PERF_RECORD_SAMPLE */
         uint64_t value, lostv;
         if (read_sample (&ctr_list[idx], datasz, &value, &lostv))
           {
             TprintfT (DBG_LT0, "hwcdrv: sig_ts=%llu: ERROR: hwcdrv_overflow:"
                       " read_sample() failed\n", sig_ts);
             lost_events->ce_pic[idx] = 3; // record a bogus value
             break;                        // failed to read sample data??
           }
         TprintfT (DBG_LT3, "hwcdrv: sig_ts=%llu: hwcdrv_overflow:"
                   " idx=%d value=%llu lost=%llu\n", (unsigned long long) sig_ts,
                   idx, (unsigned long long) value, (unsigned long long) lostv);
         if (eventp->ce_pic[idx])
           {
             TprintfT (DBG_LT2, "hwcdrv: sig_ts=%llu: WARNING: hwcdrv_overflow:"
                       " idx=%d previous sample recorded as lost_event\n", sig_ts, idx);
             lost_events->ce_pic[idx] += eventp->ce_pic[idx];
           }
         eventp->ce_pic[idx] = value;
         lost_events->ce_pic[idx] += lostv;
       }

     /* debug output for unexpected (but common) cases */
     if (idx == signal_idx)
       {
         if (num_recs != 1)
           TprintfT (DBG_LT2, "hwcdrv: sig_ts=%llu: WARNING: hwcdrv_overflow:"
                     " %d records for signal_idx=%d\n", sig_ts, num_recs, signal_idx);
       }
     else if (num_recs)
       TprintfT (DBG_LT2, "hwcdrv: sig_ts=%llu: WARNING: hwcdrv_overflow:"
                 " %d unexpected record(s) for idx=%d (signal_idx=%d)\n",
                 sig_ts, num_recs, idx, signal_idx);

     /* trigger counter restart whenever records were found */
     if (num_recs)
       {
         /* check whether to adapt the overflow interval */
         /* This is the Linux version.
          * The Solaris version is in hwprofile.c collector_update_overflow_counters().
          */
         hrtime_t min_time = global_perf_event_def[idx].min_time;
         if (min_time > 0 // overflow interval is adaptive
             && sig_ts - ctr_list[idx].last_overflow_time < min_time) // last interval below min
           {
             /* pick a new overflow interval */
             /* roughly doubled, but add funny numbers */
             /* hopefully the result is prime or not a multiple of some # of ops/loop */
             uint64_t new_period = 2 * ctr_list[idx].last_overflow_period + 37;
#if 0
             // On Solaris, we report the adjustment to the log file.
             // On Linux it's hard for us to do so since hwcdrv_pcl.c doesn't know about collector_interface, SP_JCMD_COMMENT, or COL_COMMENT_HWCADJ.
             // For now we simply don't report.
             collector_interface->writeLog ("<event kind=\"%s\" id=\"%d\">%s %d -> %d</event>\n",
                                            SP_JCMD_COMMENT, COL_COMMENT_HWCADJ, global_perf_event_def[idx].name,
                                            ctr_list[idx].last_overflow_period, new_period);
#endif
             /* There are a variety of ways of resetting the period on Linux.
              * The most elegant is
              *     ioctl(fd,PERF_EVENT_IOC_PERIOD,&period)
              * but check the perf_event_open man page for PERF_EVENT_IOC_PERIOD:
              *     > Prior to Linux 2.6.36 this ioctl always failed due to a bug in the kernel.
              *     > Prior to Linux 3.14 (or 3.7 on ARM), the new period did not take effect
              *         until after the next overflow.
              * So we're kind of stuck shutting the fd down and restarting it with the new period.
              */
             if (stop_one_ctr (idx, ctr_list))
               {
                 // EUGENE figure out what to do on error
               }
             ctr_list[idx].last_overflow_period = new_period;
             if (start_one_ctr (idx, ctr_list[idx].buf_state.pagesz, pctx, "hwcdrv: ERROR: hwcdrv_overflow (readjust overflow):"))
               {
                 // EUGENE figure out what to do on error
               }
           }
         ctr_list[idx].last_overflow_time = sig_ts;
#if 0
         ctr_list[idx].needs_restart = 1;
#else // seems to be more reliable to restart here instead of hwcdrv_sighlr_restart()
         internal_hwc_start (ctr_list[idx].fd);
#endif
       }
   }
 return 0; // OK to restart counters
}

HWCDRV_API int
hwcdrv_sighlr_restart (const hwc_event_t *pp)
{
#if 0 // restarting here doesn't seem to work as well as restarting in hwcdrv_overflow()
 hdrv_pcl_ctx_t * pctx = hdrv_pcl_state.find_vpc_ctx ();
 if (!pctx)
   {
     TprintfT (DBG_LT0, "hwcdrv: ERROR: hwcdrv_sighlr_restart: find_vpc_ctx()==NULL\n");
     return -1;
   }
 counter_state_t * ctr_list = (counter_state_t *) pctx->ctr_list;
 if (!ctr_list)
   {
     TprintfT (DBG_LT0, "hwcdrv: WARNING: hwcdrv_sighlr_restart: ctr_list is NULL\n");
     return -1;
   }
 int errors = 0;
 for (int ii = 0; ii < hdrv_pcl_state.hwcdef_cnt; ii++)
   {
     if (ctr_list[ii].needs_restart)
       errors |= internal_hwc_start (ctr_list[ii].fd);
     ctr_list[ii].needs_restart = 0;
   }
 return errors;
#else
 return 0;
#endif
}

/* create counters based on hwcdef[] */
HWCDRV_API int
hwcdrv_create_counters (unsigned hwcdef_cnt, Hwcentry *hwcdef)
{
 if (hwcdef_cnt > hdrv_pcl_about.cpcN_npics)
   {
     logerr (GTXT ("More than %d counters were specified\n"), hdrv_pcl_about.cpcN_npics); /*!*/
     return HWCFUNCS_ERROR_HWCARGS;
   }
 if (hdrv_pcl_about.cpcN_cpuver == CPUVER_UNDEFINED)
   {
     logerr (GTXT ("Processor not supported\n"));
     return HWCFUNCS_ERROR_HWCARGS;
   }

 /* add counters */
 for (unsigned idx = 0; idx < hwcdef_cnt; idx++)
   {
     perf_event_def_t *glb_event_def = &global_perf_event_def[idx];
     memset (glb_event_def, 0, sizeof (perf_event_def_t));
     unsigned int pmc_sel;
     eventsel_t evntsel;
     if (hwcfuncs_get_x86_eventsel (hwcdef[idx].reg_num,
                                    hwcdef[idx].int_name, &evntsel, &pmc_sel))
       {
         TprintfT (0, "hwcdrv: ERROR: hwcfuncs_get_x86_eventsel() failed\n");
         return HWCFUNCS_ERROR_HWCARGS;
       }
     glb_event_def->reg_num = pmc_sel;
     glb_event_def->eventsel = evntsel;
     glb_event_def->counter_preload = hwcdef[idx].val;
     glb_event_def->min_time = hwcdef[idx].min_time;
     glb_event_def->name = strdup (hwcdef[idx].name); // memory leak??? very minor
     init_perf_event (&glb_event_def->hw, glb_event_def->eventsel,
                      glb_event_def->counter_preload, hwcdef + idx);
     TprintfT (DBG_LT1, "hwcdrv: create_counters: pic=%u name='%s' interval=%lld"
               "(min_time=%lld): reg_num=0x%x eventsel=0x%llx ireset=%lld usr=%lld sys=%lld\n",
               idx, hwcdef[idx].int_name, (long long) glb_event_def->counter_preload,
               (long long) glb_event_def->min_time, (int) glb_event_def->reg_num,
               (long long) glb_event_def->eventsel,
               (long long) HW_INTERVAL_PRESET (hwcdef[idx].val),
               (long long) glb_event_def->hw.exclude_user,
               (long long) glb_event_def->hw.exclude_kernel);
   }

 hdrv_pcl_state.hwcdef_cnt = hwcdef_cnt;
 return 0;
}

HWCDRV_API int
hwcdrv_free_counters () // note: only performs shutdown for this thread
{
 hdrv_pcl_ctx_t * pctx;
 if (!COUNTERS_ENABLED ())
   return 0;
 pctx = hdrv_pcl_state.find_vpc_ctx ();
 if (!pctx)
   {
     TprintfT (0, "hwcdrv: WARNING: hwcdrv_free_counters: tsd context is NULL\n");
     return HWCFUNCS_ERROR_GENERIC;
   }
 counter_state_t *ctr_list = pctx->ctr_list;
 if (!ctr_list)
   {
     // fork child: prolog suspends hwcs, then epilog frees them
     TprintfT (DBG_LT1, "hwcdrv: WARNING: hwcdrv_free_counters: ctr_list is already NULL\n");
     return 0;
   }
 int hwc_rc = 0;
 for (int ii = 0; ii < hdrv_pcl_state.hwcdef_cnt; ii++)
   if (stop_one_ctr (ii, ctr_list))
     hwc_rc = HWCFUNCS_ERROR_GENERIC;
 TprintfT (DBG_LT1, "hwcdrv: hwcdrv_free_counters(tid=0x%lx).\n", (long) pctx->tid);
 pctx->ctr_list = NULL;
 return hwc_rc;
}

HWCDRV_API int
hwcdrv_start (void) /* must be called from each thread ? */
{
 hdrv_pcl_ctx_t *pctx = NULL;
 if (!COUNTERS_ENABLED ())
   {
     TprintfT (DBG_LT1, "hwcdrv: WARNING: hwcdrv_start: no counters to start \n");
     return 0;
   }
 if (!hdrv_pcl_state.library_ok)
   {
     TprintfT (0, "hwcdrv: ERROR: hwcdrv_start: library is not open\n");
     return HWCFUNCS_ERROR_NOT_SUPPORTED;
   }

 /*
  * set up per-thread context
  */
 pctx = hdrv_pcl_state.find_vpc_ctx ();
 if (!pctx)
   {
     TprintfT (0, "hwcdrv: ERROR: hwcdrv_start: tsd context is NULL\n");
     return HWCFUNCS_ERROR_UNEXPECTED;
   }
 pctx->tid = hwcdrv_gettid ();
 TprintfT (DBG_LT1, "hwcdrv: hwcdrv_start(tid=0x%lx)\n", (long) pctx->tid);

 /*
  * create per-thread counter list
  */
 counter_state_t *ctr_list = (counter_state_t *) calloc (hdrv_pcl_state.hwcdef_cnt,
                                                         sizeof (counter_state_t));
 if (!ctr_list)
   {
     TprintfT (0, "hwcdrv: ERROR: hwcdrv_start: calloc(ctr_list) failed\n");
     return HWCFUNCS_ERROR_MEMORY;
   }
 int ii;
 for (ii = 0; ii < hdrv_pcl_state.hwcdef_cnt; ii++)
   ctr_list[ii].fd = -1; // invalidate fds in case we have to close prematurely
 pctx->ctr_list = ctr_list;

 /*
  * bind the counters
  */
 size_t pgsz = sysconf (_SC_PAGESIZE);
 for (ii = 0; ii < hdrv_pcl_state.hwcdef_cnt; ii++)
   {
     ctr_list[ii].last_overflow_period = global_perf_event_def[ii].hw.sample_period;
     if (start_one_ctr (ii, pgsz, pctx, "hwcdrv: ERROR: hwcdrv_start:")) goto hwcdrv_start_cleanup;
   }

 /*
  * start the counters
  */
 for (ii = 0; ii < hdrv_pcl_state.hwcdef_cnt; ii++)
   {
     int rc = internal_hwc_start (ctr_list[ii].fd);
     if (rc < 0)
       goto hwcdrv_start_cleanup;
   }
 return 0;

hwcdrv_start_cleanup:
 hwcdrv_free_counters (); // PERF_EVENT_IOC_DISABLE and close() for all fds
 return HWCFUNCS_ERROR_UNAVAIL;
}

HWCDRV_API int
hwcdrv_lwp_suspend (void) /* must be called from each thread */
{
 if (!COUNTERS_ENABLED ())
   {
     TprintfT (DBG_LT1, "hwcdrv: WARNING: hwcdrv_lwp_suspend: no counters\n");
     return 0;
   }
 TprintfT (DBG_LT1, "hwcdrv: hwcdrv_lwp_suspend()\n");
 return hwcdrv_free_counters ();
}

HWCDRV_API int
hwcdrv_lwp_resume (void) /* must be called from each thread */
{
 if (!COUNTERS_ENABLED ())
   {
     TprintfT (DBG_LT1, "hwcdrv: WARNING: hwcdrv_lwp_resume: no counters\n");
     return 0;
   }
 TprintfT (DBG_LT1, "hwcdrv: hwcdrv_lwp_resume()\n");
 return hwcdrv_start ();
}

HWCDRV_API int
hwcdrv_read_events (hwc_event_t *overflow_data, hwc_event_samples_t *sampled_data)
{
 overflow_data->ce_hrt = 0;
 for (int i = 0; i < MAX_PICS; i++)
   {
     overflow_data->ce_pic[i] = 0;
     if (sampled_data)
       HWCFUNCS_SAMPLE_RESET (&sampled_data->sample[i]);
   }
 return 0;
}

/*---------------------------------------------------------------------------*/
/* HWCDRV_API */

hwcdrv_api_t hwcdrv_pcl_api = {
 hwcdrv_init,
 hwcdrv_get_info,
 hwcdrv_enable_mt,
 hwcdrv_get_descriptions,
 hwcdrv_assign_regnos,
 hwcdrv_create_counters,
 hwcdrv_start,
 hwcdrv_overflow,
 hwcdrv_read_events,
 hwcdrv_sighlr_restart,
 hwcdrv_lwp_suspend,
 hwcdrv_lwp_resume,
 hwcdrv_free_counters,
 hwcdrv_lwp_init,
 hwcdrv_lwp_fini,
   -1                      // hwcdrv_init_status
};