op_model_ppro.c

/*
 * @file op_model_ppro.h
 * Family 6 perfmon and architectural perfmon MSR operations
 *
 * @remark Copyright 2002 OProfile authors
 * @remark Copyright 2008 Intel Corporation
 * @remark Read the file COPYING
 *
 * @author John Levon
 * @author Philippe Elie
 * @author Graydon Hoare
 * @author Andi Kleen
 * @author Robert Richter <[email protected]>
 */

#include <linux/oprofile.h>
#include <linux/slab.h>
#include <asm/ptrace.h>
#include <asm/msr.h>
#include <asm/apic.h>
#include <asm/nmi.h>

#include "op_x86_model.h"
#include "op_counter.h"

static int num_counters = 2;
static int counter_width = 32;

#define MSR_PPRO_EVENTSEL_RESERVED	((0xFFFFFFFFULL<<32)|(1ULL<<21))

static u64 *reset_value;

static void ppro_shutdown(struct op_msrs const * const msrs)
{
	int i;

	for (i = 0; i < num_counters; ++i) {
		if (!msrs->counters[i].addr)
			continue;
		release_perfctr_nmi(MSR_P6_PERFCTR0 + i);
		release_evntsel_nmi(MSR_P6_EVNTSEL0 + i);
	}
	if (reset_value) {
		kfree(reset_value);
		reset_value = NULL;
	}
}

static int ppro_fill_in_addresses(struct op_msrs * const msrs)
{
	int i;

	for (i = 0; i < num_counters; i++) {
		if (!reserve_perfctr_nmi(MSR_P6_PERFCTR0 + i))
			goto fail;
		if (!reserve_evntsel_nmi(MSR_P6_EVNTSEL0 + i)) {
			release_perfctr_nmi(MSR_P6_PERFCTR0 + i);
			goto fail;
		}
		/* both registers must be reserved */
		msrs->counters[i].addr = MSR_P6_PERFCTR0 + i;
		msrs->controls[i].addr = MSR_P6_EVNTSEL0 + i;
		continue;
	fail:
		if (!counter_config[i].enabled)
			continue;
		op_x86_warn_reserved(i);
		ppro_shutdown(msrs);
		return -EBUSY;
	}

	return 0;
}


static void ppro_setup_ctrs(struct op_x86_model_spec const *model,
			    struct op_msrs const * const msrs)
{
	u64 val;
	int i;

	if (!reset_value) {
		reset_value = kzalloc(sizeof(reset_value[0]) * num_counters,
					GFP_ATOMIC);
		if (!reset_value)
			return;
	}

	if (cpu_has_arch_perfmon) {
		union cpuid10_eax eax;
		eax.full = cpuid_eax(0xa);

		/*
		 * For Core2 (family 6, model 15), don't reset the
		 * counter width:
		 */
		if (!(eax.split.version_id == 0 &&
			__this_cpu_read(cpu_info.x86) == 6 &&
				__this_cpu_read(cpu_info.x86_model) == 15)) {

			if (counter_width < eax.split.bit_width)
				counter_width = eax.split.bit_width;
		}
	}

	/* clear all counters */
	for (i = 0; i < num_counters; ++i) {
		if (!msrs->controls[i].addr)
			continue;
		rdmsrl(msrs->controls[i].addr, val);
		if (val & ARCH_PERFMON_EVENTSEL_ENABLE)
			op_x86_warn_in_use(i);
		val &= model->reserved;
		wrmsrl(msrs->controls[i].addr, val);
		/*
		 * avoid a false detection of ctr overflows in NMI *
		 * handler
		 */
		wrmsrl(msrs->counters[i].addr, -1LL);
	}

	/* enable active counters */
	for (i = 0; i < num_counters; ++i) {
		if (counter_config[i].enabled && msrs->counters[i].addr) {
			reset_value[i] = counter_config[i].count;
			wrmsrl(msrs->counters[i].addr, -reset_value[i]);
			rdmsrl(msrs->controls[i].addr, val);
			val &= model->reserved;
			val |= op_x86_get_ctrl(model, &counter_config[i]);
			wrmsrl(msrs->controls[i].addr, val);
		} else {
			reset_value[i] = 0;
		}
	}
}


static int ppro_check_ctrs(struct pt_regs * const regs,
			   struct op_msrs const * const msrs)
{
	u64 val;
	int i;

	/*
	 * This can happen if perf counters are in use when
	 * we steal the die notifier NMI.
	 */
	if (unlikely(!reset_value))
		goto out;

	for (i = 0; i < num_counters; ++i) {
		if (!reset_value[i])
			continue;
		rdmsrl(msrs->counters[i].addr, val);
		if (val & (1ULL << (counter_width - 1)))
			continue;
		oprofile_add_sample(regs, i);
		wrmsrl(msrs->counters[i].addr, -reset_value[i]);
	}

out:
	/* Only P6 based Pentium M need to re-unmask the apic vector but it
	 * doesn't hurt other P6 variant */
	apic_write(APIC_LVTPC, apic_read(APIC_LVTPC) & ~APIC_LVT_MASKED);

	/* We can't work out if we really handled an interrupt. We
	 * might have caught a *second* counter just after overflowing
	 * the interrupt for this counter then arrives
	 * and we don't find a counter that's overflowed, so we
	 * would return 0 and get dazed + confused. Instead we always
	 * assume we found an overflow. This sucks.
	 */
	return 1;
}


static void ppro_start(struct op_msrs const * const msrs)
{
	u64 val;
	int i;

	if (!reset_value)
		return;
	for (i = 0; i < num_counters; ++i) {
		if (reset_value[i]) {
			rdmsrl(msrs->controls[i].addr, val);
			val |= ARCH_PERFMON_EVENTSEL_ENABLE;
			wrmsrl(msrs->controls[i].addr, val);
		}
	}
}


static void ppro_stop(struct op_msrs const * const msrs)
{
	u64 val;
	int i;

	if (!reset_value)
		return;
	for (i = 0; i < num_counters; ++i) {
		if (!reset_value[i])
			continue;
		rdmsrl(msrs->controls[i].addr, val);
		val &= ~ARCH_PERFMON_EVENTSEL_ENABLE;
		wrmsrl(msrs->controls[i].addr, val);
	}
}

struct op_x86_model_spec op_ppro_spec = {
	.num_counters		= 2,
	.num_controls		= 2,
	.reserved		= MSR_PPRO_EVENTSEL_RESERVED,
	.fill_in_addresses	= &ppro_fill_in_addresses,
	.setup_ctrs		= &ppro_setup_ctrs,
	.check_ctrs		= &ppro_check_ctrs,
	.start			= &ppro_start,
	.stop			= &ppro_stop,
	.shutdown		= &ppro_shutdown
};

/*
 * Architectural performance monitoring.
 *
 * Newer Intel CPUs (Core1+) have support for architectural
 * events described in CPUID 0xA. See the IA32 SDM Vol3b.18 for details.
 * The advantage of this is that it can be done without knowing about
 * the specific CPU.
 */

static void arch_perfmon_setup_counters(void)
{
	union cpuid10_eax eax;

	eax.full = cpuid_eax(0xa);

	/* Workaround for BIOS bugs in 6/15. Taken from perfmon2 */
	if (eax.split.version_id == 0 && __this_cpu_read(cpu_info.x86) == 6 &&
		__this_cpu_read(cpu_info.x86_model) == 15) {
		eax.split.version_id = 2;
		eax.split.num_counters = 2;
		eax.split.bit_width = 40;
	}

	num_counters = eax.split.num_counters;

	op_arch_perfmon_spec.num_counters = num_counters;
	op_arch_perfmon_spec.num_controls = num_counters;
}

static int arch_perfmon_init(struct oprofile_operations *ignore)
{
	arch_perfmon_setup_counters();
	return 0;
}

struct op_x86_model_spec op_arch_perfmon_spec = {
	.reserved		= MSR_PPRO_EVENTSEL_RESERVED,
	.init			= &arch_perfmon_init,
	/* num_counters/num_controls filled in at runtime */
	.fill_in_addresses	= &ppro_fill_in_addresses,
	/* user space does the cpuid check for available events */
	.setup_ctrs		= &ppro_setup_ctrs,
	.check_ctrs		= &ppro_check_ctrs,
	.start			= &ppro_start,
	.stop			= &ppro_stop,
	.shutdown		= &ppro_shutdown
};