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