LXR linux/arch/alpha/oprofile/op_model

   1/**
   2 * @file arch/alpha/oprofile/op_model_ev4.c
   3 *
   4 * @remark Copyright 2002 OProfile authors
   5 * @remark Read the file COPYING
   6 *
   7 * @author Richard Henderson <rth@twiddle.net>
   8 */
   9
  10#include <linux/oprofile.h>
  11#include <linux/init.h>
  12#include <linux/smp.h>
  13#include <asm/ptrace.h>
  14#include <asm/system.h>
  15
  16#include "op_impl.h"
  17
  18
  19/* Compute all of the registers in preparation for enabling profiling.  */
  20
  21static void
  22ev4_reg_setup(struct op_register_config *reg,
  23              struct op_counter_config *ctr,
  24              struct op_system_config *sys)
  25{
  26        unsigned long ctl = 0, count, hilo;
  27
  28        /* Select desired events.  We've mapped the event numbers
  29           such that they fit directly into the event selection fields.
  30
  31           Note that there is no "off" setting.  In both cases we select
  32           the EXTERNAL event source, hoping that it'll be the lowest
  33           frequency, and set the frequency counter to LOW.  The interrupts
  34           for these "disabled" counter overflows are ignored by the
  35           interrupt handler.
  36
  37           This is most irritating, because the hardware *can* enable and
  38           disable the interrupts for these counters independently, but the
  39           wrperfmon interface doesn't allow it.  */
  40
  41        ctl |= (ctr[0].enabled ? ctr[0].event << 8 : 14 << 8);
  42        ctl |= (ctr[1].enabled ? (ctr[1].event - 16) << 32 : 7ul << 32);
  43
  44        /* EV4 can not read or write its counter registers.  The only
  45           thing one can do at all is see if you overflow and get an
  46           interrupt.  We can set the width of the counters, to some
  47           extent.  Take the interrupt count selected by the user,
  48           map it onto one of the possible values, and write it back.  */
  49
  50        count = ctr[0].count;
  51        if (count <= 4096)
  52                count = 4096, hilo = 1;
  53        else
  54                count = 65536, hilo = 0;
  55        ctr[0].count = count;
  56        ctl |= (ctr[0].enabled && hilo) << 3;
  57
  58        count = ctr[1].count;
  59        if (count <= 256)
  60                count = 256, hilo = 1;
  61        else
  62                count = 4096, hilo = 0;
  63        ctr[1].count = count;
  64        ctl |= (ctr[1].enabled && hilo);
  65
  66        reg->mux_select = ctl;
  67
  68        /* Select performance monitoring options.  */
  69        /* ??? Need to come up with some mechanism to trace only
  70           selected processes.  EV4 does not have a mechanism to
  71           select kernel or user mode only.  For now, enable always.  */
  72        reg->proc_mode = 0;
  73
  74        /* Frequency is folded into mux_select for EV4.  */
  75        reg->freq = 0;
  76
  77        /* See above regarding no writes.  */
  78        reg->reset_values = 0;
  79        reg->need_reset = 0;
  80
  81}
  82
  83/* Program all of the registers in preparation for enabling profiling.  */
  84
  85static void
  86ev4_cpu_setup(void *x)
  87{
  88        struct op_register_config *reg = x;
  89
  90        wrperfmon(2, reg->mux_select);
  91        wrperfmon(3, reg->proc_mode);
  92}
  93
  94static void
  95ev4_handle_interrupt(unsigned long which, struct pt_regs *regs,
  96                     struct op_counter_config *ctr)
  97{
  98        /* EV4 can't properly disable counters individually.
  99           Discard "disabled" events now.  */
 100        if (!ctr[which].enabled)
 101                return;
 102
 103        /* Record the sample.  */
 104        oprofile_add_sample(regs, which);
 105}
 106
 107
 108struct op_axp_model op_model_ev4 = {
 109        .reg_setup              = ev4_reg_setup,
 110        .cpu_setup              = ev4_cpu_setup,
 111        .reset_ctr              = NULL,
 112        .handle_interrupt       = ev4_handle_interrupt,
 113        .cpu_type               = "alpha/ev4",
 114        .num_counters           = 2,
 115        .can_set_proc_mode      = 0,
 116};
 117