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/**
* @file cpu_type.c
* CPU determination
*
* @remark Copyright 2002 OProfile authors
* @remark Read the file COPYING
*
* @author John Levon
* @author Philippe Elie
*/
#include "oprofile.h"
#include "op_msr.h"
#include <linux/smp.h>
EXPORT_NO_SYMBOLS;
MODULE_PARM(force_rtc, "i");
MODULE_PARM_DESC(force_rtc, "force RTC mode.");
static int force_rtc;
#ifndef HT_SUPPORT
/**
* p4_threads - determines the number of logical processor threads in a die
*
* returns number of threads in p4 die (1 for non-HT processors)
*/
static int p4_threads(void)
{
int processor_threads = 1;
#ifdef CONFIG_SMP
if (test_bit(X86_FEATURE_HT, &current_cpu_data.x86_capability)) {
/* This it a Pentium 4 with HT, find number of threads */
int eax, ebx, ecx, edx;
cpuid (1, &eax, &ebx, &ecx, &edx);
processor_threads = (ebx >> 16) & 0xff;
}
#endif /* CONFIG_SMP */
return processor_threads;
}
#ifdef CONFIG_SMP
/**
* do_cpu_id - Call the cpuid instruction and fill in data at passed address
*
* We expect that data is pointing to an array of unsigned chars as big as there
* are cpus in an smp system.
*/
static void do_cpu_id(void * data)
{
int eax, ebx, ecx, edx;
unsigned char * ptr = (unsigned char *) data;
cpuid(1, &eax, &ebx, &ecx, &edx);
/* bits EBX[31:24] define APIC ID */
ptr[smp_processor_id()] = (unsigned char) ((ebx & 0xff000000) >> 24);
}
#endif
/**
* p4_ht_enabled - Determines if Hyper Threading is enabled or not.
*
* A P4 can be capable of HT, but not enabled via BIOS. The check for
* this is unfortunately not simple and involves running cpuid on all
* logical processors and checking for bits in the APIC_ID fields.
* As per Intel docs. Returns 1 if enabled, 0 otherwise.
*
*/
static int p4_ht_enabled(void)
{
#ifndef CONFIG_SMP
return 0;
#else
int enabled, threads, i;
unsigned char mask;
unsigned char apic_id[smp_num_cpus];
unsigned int cpu;
/* First check for capability */
threads = p4_threads();
if (threads == 1) return 0;
/* Create mask for low order bits */
mask = 0xff;
i = 1;
while (i < threads) {
i *= 2;
mask <<= 1;
}
/* Get APIC_ID from all logial procs and self */
smp_call_function(do_cpu_id, apic_id, 1, 1);
do_cpu_id(apic_id);
/* If the low order bits are on, then HT is enabled */
enabled = 0;
cpu = 0;
do {
if (apic_id[cpu] & ~mask) {
enabled = 1;
break;
}
cpu++;
} while (cpu < smp_num_cpus);
return enabled;
#endif /* CONFIG_SMP */
}
#endif /* !HT_SUPPORT */
op_cpu p4_cpu_type(void)
{
__u8 model = current_cpu_data.x86_model;
if (model <= 4) {
#ifdef HT_SUPPORT
if (smp_num_siblings == 1) {
return CPU_P4;
} else if (smp_num_siblings == 2) {
return CPU_P4_HT2;
} else {
printk(KERN_INFO
"oprofile: P4 HT unsupported number of siblings"
"processor, reverting to RTC\n");
return CPU_RTC;
}
#else
/* Cannot handle enabled HT P4 hardware */
if ((p4_threads() > 1) && p4_ht_enabled()) {
printk(KERN_INFO
"oprofile: P4 HT enabled, reverting to RTC\n");
return CPU_RTC;
}
else
return CPU_P4;
#endif
} else
/* Do not know what it is */
return CPU_RTC;
}
__init op_cpu get_cpu_type(void)
{
__u8 vendor = current_cpu_data.x86_vendor;
__u8 family = current_cpu_data.x86;
__u8 model = current_cpu_data.x86_model;
__u16 val;
if (force_rtc)
return CPU_RTC;
switch (vendor) {
case X86_VENDOR_AMD:
if (family == 6) {
/* certain models of K7 does not have apic.
* Check if apic is really present before enabling it.
* IA32 V3, 7.4.1 */
val = cpuid_edx(1);
if (!(val & (1 << 9)))
return CPU_RTC;
return CPU_ATHLON;
}
if (family == 15)
return CPU_HAMMER;
return CPU_RTC;
case X86_VENDOR_INTEL:
switch (family) {
default:
return CPU_RTC;
case 6:
/* A P6-class processor */
if (model == 14)
return CPU_CORE;
if (model > 0xd)
return CPU_RTC;
if (model > 5)
return CPU_PIII;
else if (model > 2)
return CPU_PII;
return CPU_PPRO;
case 0xf:
return p4_cpu_type();
}
default:
return CPU_RTC;
}
}