153 lines
3.7 KiB
C
153 lines
3.7 KiB
C
/*
|
|
* local apic based NMI watchdog for various CPUs.
|
|
*
|
|
* This file also handles reservation of performance counters for coordination
|
|
* with other users (like oprofile).
|
|
*
|
|
* Note that these events normally don't tick when the CPU idles. This means
|
|
* the frequency varies with CPU load.
|
|
*
|
|
* Original code for K7/P6 written by Keith Owens
|
|
*
|
|
*/
|
|
|
|
#include <linux/percpu.h>
|
|
#include <linux/module.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/bitops.h>
|
|
#include <linux/smp.h>
|
|
#include <asm/nmi.h>
|
|
#include <linux/kprobes.h>
|
|
|
|
#include <asm/apic.h>
|
|
#include <asm/perf_event.h>
|
|
|
|
/*
|
|
* this number is calculated from Intel's MSR_P4_CRU_ESCR5 register and it's
|
|
* offset from MSR_P4_BSU_ESCR0.
|
|
*
|
|
* It will be the max for all platforms (for now)
|
|
*/
|
|
#define NMI_MAX_COUNTER_BITS 66
|
|
|
|
/*
|
|
* perfctr_nmi_owner tracks the ownership of the perfctr registers:
|
|
* evtsel_nmi_owner tracks the ownership of the event selection
|
|
* - different performance counters/ event selection may be reserved for
|
|
* different subsystems this reservation system just tries to coordinate
|
|
* things a little
|
|
*/
|
|
static DECLARE_BITMAP(perfctr_nmi_owner, NMI_MAX_COUNTER_BITS);
|
|
static DECLARE_BITMAP(evntsel_nmi_owner, NMI_MAX_COUNTER_BITS);
|
|
|
|
/* converts an msr to an appropriate reservation bit */
|
|
static inline unsigned int nmi_perfctr_msr_to_bit(unsigned int msr)
|
|
{
|
|
/* returns the bit offset of the performance counter register */
|
|
switch (boot_cpu_data.x86_vendor) {
|
|
case X86_VENDOR_AMD:
|
|
return msr - MSR_K7_PERFCTR0;
|
|
case X86_VENDOR_INTEL:
|
|
if (cpu_has(&boot_cpu_data, X86_FEATURE_ARCH_PERFMON))
|
|
return msr - MSR_ARCH_PERFMON_PERFCTR0;
|
|
|
|
switch (boot_cpu_data.x86) {
|
|
case 6:
|
|
return msr - MSR_P6_PERFCTR0;
|
|
case 15:
|
|
return msr - MSR_P4_BPU_PERFCTR0;
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* converts an msr to an appropriate reservation bit
|
|
* returns the bit offset of the event selection register
|
|
*/
|
|
static inline unsigned int nmi_evntsel_msr_to_bit(unsigned int msr)
|
|
{
|
|
/* returns the bit offset of the event selection register */
|
|
switch (boot_cpu_data.x86_vendor) {
|
|
case X86_VENDOR_AMD:
|
|
return msr - MSR_K7_EVNTSEL0;
|
|
case X86_VENDOR_INTEL:
|
|
if (cpu_has(&boot_cpu_data, X86_FEATURE_ARCH_PERFMON))
|
|
return msr - MSR_ARCH_PERFMON_EVENTSEL0;
|
|
|
|
switch (boot_cpu_data.x86) {
|
|
case 6:
|
|
return msr - MSR_P6_EVNTSEL0;
|
|
case 15:
|
|
return msr - MSR_P4_BSU_ESCR0;
|
|
}
|
|
}
|
|
return 0;
|
|
|
|
}
|
|
|
|
/* checks for a bit availability (hack for oprofile) */
|
|
int avail_to_resrv_perfctr_nmi_bit(unsigned int counter)
|
|
{
|
|
BUG_ON(counter > NMI_MAX_COUNTER_BITS);
|
|
|
|
return !test_bit(counter, perfctr_nmi_owner);
|
|
}
|
|
EXPORT_SYMBOL(avail_to_resrv_perfctr_nmi_bit);
|
|
|
|
int reserve_perfctr_nmi(unsigned int msr)
|
|
{
|
|
unsigned int counter;
|
|
|
|
counter = nmi_perfctr_msr_to_bit(msr);
|
|
/* register not managed by the allocator? */
|
|
if (counter > NMI_MAX_COUNTER_BITS)
|
|
return 1;
|
|
|
|
if (!test_and_set_bit(counter, perfctr_nmi_owner))
|
|
return 1;
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(reserve_perfctr_nmi);
|
|
|
|
void release_perfctr_nmi(unsigned int msr)
|
|
{
|
|
unsigned int counter;
|
|
|
|
counter = nmi_perfctr_msr_to_bit(msr);
|
|
/* register not managed by the allocator? */
|
|
if (counter > NMI_MAX_COUNTER_BITS)
|
|
return;
|
|
|
|
clear_bit(counter, perfctr_nmi_owner);
|
|
}
|
|
EXPORT_SYMBOL(release_perfctr_nmi);
|
|
|
|
int reserve_evntsel_nmi(unsigned int msr)
|
|
{
|
|
unsigned int counter;
|
|
|
|
counter = nmi_evntsel_msr_to_bit(msr);
|
|
/* register not managed by the allocator? */
|
|
if (counter > NMI_MAX_COUNTER_BITS)
|
|
return 1;
|
|
|
|
if (!test_and_set_bit(counter, evntsel_nmi_owner))
|
|
return 1;
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(reserve_evntsel_nmi);
|
|
|
|
void release_evntsel_nmi(unsigned int msr)
|
|
{
|
|
unsigned int counter;
|
|
|
|
counter = nmi_evntsel_msr_to_bit(msr);
|
|
/* register not managed by the allocator? */
|
|
if (counter > NMI_MAX_COUNTER_BITS)
|
|
return;
|
|
|
|
clear_bit(counter, evntsel_nmi_owner);
|
|
}
|
|
EXPORT_SYMBOL(release_evntsel_nmi);
|