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op_model_power4.c

/*
 * Copyright (C) 2004 Anton Blanchard <anton@au.ibm.com>, IBM
 * Added mmcra[slot] support:
 * Copyright (C) 2006-2007 Will Schmidt <willschm@us.ibm.com>, IBM
 *
 * 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
 * 2 of the License, or (at your option) any later version.
 */

#include <linux/oprofile.h>
#include <linux/init.h>
#include <linux/smp.h>
#include <asm/firmware.h>
#include <asm/ptrace.h>
#include <asm/system.h>
#include <asm/processor.h>
#include <asm/cputable.h>
#include <asm/rtas.h>
#include <asm/oprofile_impl.h>
#include <asm/reg.h>

#define dbg(args...)

static unsigned long reset_value[OP_MAX_COUNTER];

static int oprofile_running;

/* mmcr values are set in power4_reg_setup, used in power4_cpu_setup */
static u32 mmcr0_val;
static u64 mmcr1_val;
static u64 mmcra_val;

static int power4_reg_setup(struct op_counter_config *ctr,
                       struct op_system_config *sys,
                       int num_ctrs)
{
      int i;

      /*
       * The performance counter event settings are given in the mmcr0,
       * mmcr1 and mmcra values passed from the user in the
       * op_system_config structure (sys variable).
       */
      mmcr0_val = sys->mmcr0;
      mmcr1_val = sys->mmcr1;
      mmcra_val = sys->mmcra;

      for (i = 0; i < cur_cpu_spec->num_pmcs; ++i)
            reset_value[i] = 0x80000000UL - ctr[i].count;

      /* setup user and kernel profiling */
      if (sys->enable_kernel)
            mmcr0_val &= ~MMCR0_KERNEL_DISABLE;
      else
            mmcr0_val |= MMCR0_KERNEL_DISABLE;

      if (sys->enable_user)
            mmcr0_val &= ~MMCR0_PROBLEM_DISABLE;
      else
            mmcr0_val |= MMCR0_PROBLEM_DISABLE;

      return 0;
}

extern void ppc64_enable_pmcs(void);

/*
 * Older CPUs require the MMCRA sample bit to be always set, but newer 
 * CPUs only want it set for some groups. Eventually we will remove all
 * knowledge of this bit in the kernel, oprofile userspace should be
 * setting it when required.
 *
 * In order to keep current installations working we force the bit for
 * those older CPUs. Once everyone has updated their oprofile userspace we
 * can remove this hack.
 */
static inline int mmcra_must_set_sample(void)
{
      if (__is_processor(PV_POWER4) || __is_processor(PV_POWER4p) ||
          __is_processor(PV_970) || __is_processor(PV_970FX) ||
          __is_processor(PV_970MP) || __is_processor(PV_970GX))
            return 1;

      return 0;
}

static int power4_cpu_setup(struct op_counter_config *ctr)
{
      unsigned int mmcr0 = mmcr0_val;
      unsigned long mmcra = mmcra_val;

      ppc64_enable_pmcs();

      /* set the freeze bit */
      mmcr0 |= MMCR0_FC;
      mtspr(SPRN_MMCR0, mmcr0);

      mmcr0 |= MMCR0_FCM1|MMCR0_PMXE|MMCR0_FCECE;
      mmcr0 |= MMCR0_PMC1CE|MMCR0_PMCjCE;
      mtspr(SPRN_MMCR0, mmcr0);

      mtspr(SPRN_MMCR1, mmcr1_val);

      if (mmcra_must_set_sample())
            mmcra |= MMCRA_SAMPLE_ENABLE;
      mtspr(SPRN_MMCRA, mmcra);

      dbg("setup on cpu %d, mmcr0 %lx\n", smp_processor_id(),
          mfspr(SPRN_MMCR0));
      dbg("setup on cpu %d, mmcr1 %lx\n", smp_processor_id(),
          mfspr(SPRN_MMCR1));
      dbg("setup on cpu %d, mmcra %lx\n", smp_processor_id(),
          mfspr(SPRN_MMCRA));

      return 0;
}

static int power4_start(struct op_counter_config *ctr)
{
      int i;
      unsigned int mmcr0;

      /* set the PMM bit (see comment below) */
      mtmsrd(mfmsr() | MSR_PMM);

      for (i = 0; i < cur_cpu_spec->num_pmcs; ++i) {
            if (ctr[i].enabled) {
                  classic_ctr_write(i, reset_value[i]);
            } else {
                  classic_ctr_write(i, 0);
            }
      }

      mmcr0 = mfspr(SPRN_MMCR0);

      /*
       * We must clear the PMAO bit on some (GQ) chips. Just do it
       * all the time
       */
      mmcr0 &= ~MMCR0_PMAO;

      /*
       * now clear the freeze bit, counting will not start until we
       * rfid from this excetion, because only at that point will
       * the PMM bit be cleared
       */
      mmcr0 &= ~MMCR0_FC;
      mtspr(SPRN_MMCR0, mmcr0);

      oprofile_running = 1;

      dbg("start on cpu %d, mmcr0 %x\n", smp_processor_id(), mmcr0);
      return 0;
}

static void power4_stop(void)
{
      unsigned int mmcr0;

      /* freeze counters */
      mmcr0 = mfspr(SPRN_MMCR0);
      mmcr0 |= MMCR0_FC;
      mtspr(SPRN_MMCR0, mmcr0);

      oprofile_running = 0;

      dbg("stop on cpu %d, mmcr0 %x\n", smp_processor_id(), mmcr0);

      mb();
}

/* Fake functions used by canonicalize_pc */
static void __attribute_used__ hypervisor_bucket(void)
{
}

static void __attribute_used__ rtas_bucket(void)
{
}

static void __attribute_used__ kernel_unknown_bucket(void)
{
}

/*
 * On GQ and newer the MMCRA stores the HV and PR bits at the time
 * the SIAR was sampled. We use that to work out if the SIAR was sampled in
 * the hypervisor, our exception vectors or RTAS.
 * If the MMCRA_SAMPLE_ENABLE bit is set, we can use the MMCRA[slot] bits
 * to more accurately identify the address of the sampled instruction. The
 * mmcra[slot] bits represent the slot number of a sampled instruction
 * within an instruction group.  The slot will contain a value between 1
 * and 5 if MMCRA_SAMPLE_ENABLE is set, otherwise 0.
 */
static unsigned long get_pc(struct pt_regs *regs)
{
      unsigned long pc = mfspr(SPRN_SIAR);
      unsigned long mmcra;
      unsigned long slot;

      /* Cant do much about it */
      if (!cur_cpu_spec->oprofile_mmcra_sihv)
            return pc;

      mmcra = mfspr(SPRN_MMCRA);

      if (mmcra & MMCRA_SAMPLE_ENABLE) {
            slot = ((mmcra & MMCRA_SLOT) >> MMCRA_SLOT_SHIFT);
            if (slot > 1)
                  pc += 4 * (slot - 1);
      }

      /* Were we in the hypervisor? */
      if (firmware_has_feature(FW_FEATURE_LPAR) &&
          (mmcra & cur_cpu_spec->oprofile_mmcra_sihv))
            /* function descriptor madness */
            return *((unsigned long *)hypervisor_bucket);

      /* We were in userspace, nothing to do */
      if (mmcra & cur_cpu_spec->oprofile_mmcra_sipr)
            return pc;

#ifdef CONFIG_PPC_RTAS
      /* Were we in RTAS? */
      if (pc >= rtas.base && pc < (rtas.base + rtas.size))
            /* function descriptor madness */
            return *((unsigned long *)rtas_bucket);
#endif

      /* Were we in our exception vectors or SLB real mode miss handler? */
      if (pc < 0x1000000UL)
            return (unsigned long)__va(pc);

      /* Not sure where we were */
      if (!is_kernel_addr(pc))
            /* function descriptor madness */
            return *((unsigned long *)kernel_unknown_bucket);

      return pc;
}

static int get_kernel(unsigned long pc, unsigned long mmcra)
{
      int is_kernel;

      if (!cur_cpu_spec->oprofile_mmcra_sihv) {
            is_kernel = is_kernel_addr(pc);
      } else {
            is_kernel = ((mmcra & cur_cpu_spec->oprofile_mmcra_sipr) == 0);
      }

      return is_kernel;
}

static void power4_handle_interrupt(struct pt_regs *regs,
                            struct op_counter_config *ctr)
{
      unsigned long pc;
      int is_kernel;
      int val;
      int i;
      unsigned int mmcr0;
      unsigned long mmcra;

      mmcra = mfspr(SPRN_MMCRA);

      pc = get_pc(regs);
      is_kernel = get_kernel(pc, mmcra);

      /* set the PMM bit (see comment below) */
      mtmsrd(mfmsr() | MSR_PMM);

      for (i = 0; i < cur_cpu_spec->num_pmcs; ++i) {
            val = classic_ctr_read(i);
            if (val < 0) {
                  if (oprofile_running && ctr[i].enabled) {
                        oprofile_add_ext_sample(pc, regs, i, is_kernel);
                        classic_ctr_write(i, reset_value[i]);
                  } else {
                        classic_ctr_write(i, 0);
                  }
            }
      }

      mmcr0 = mfspr(SPRN_MMCR0);

      /* reset the perfmon trigger */
      mmcr0 |= MMCR0_PMXE;

      /*
       * We must clear the PMAO bit on some (GQ) chips. Just do it
       * all the time
       */
      mmcr0 &= ~MMCR0_PMAO;

      /* Clear the appropriate bits in the MMCRA */
      mmcra &= ~cur_cpu_spec->oprofile_mmcra_clear;
      mtspr(SPRN_MMCRA, mmcra);

      /*
       * now clear the freeze bit, counting will not start until we
       * rfid from this exception, because only at that point will
       * the PMM bit be cleared
       */
      mmcr0 &= ~MMCR0_FC;
      mtspr(SPRN_MMCR0, mmcr0);
}

struct op_powerpc_model op_model_power4 = {
      .reg_setup        = power4_reg_setup,
      .cpu_setup        = power4_cpu_setup,
      .start                  = power4_start,
      .stop             = power4_stop,
      .handle_interrupt = power4_handle_interrupt,
};

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