RE: [patch 9/9] x86, bts, ftrace: a BTS ftrace plug-in prototype

[Metzger, Markus T]

>-----Original Message-----
>From: Andi Kleen [mailto:andi@xxxxxxxxxxxxxx] 
>Sent: Dienstag, 25. November 2008 11:13
>To: Metzger, Markus T

>Markus Metzger <markus.t.metzger@xxxxxxxxx> writes:
>
>Basic idea looks very useful. Thanks.
>
>> +static void bts_trace_cpuinit(struct cpuinfo_x86 *c)
>
>That should be somewhere generic I think. Doesn't ptrace have it too?

It does. All the BTS bits currently live in ptrace.c - that had been the only user, so far. I will move them into ds.c, but this will take a few patches.

Ingo said its important to have an early prototype. So I did the first version with very restricted functionality and some duplicate code.


regards,
markus.

>
>-Andi
>
>
>> +{
>> +	switch (c->x86) {
>> +	case 0x6:
>> +		switch (c->x86_model) {
>> +		case 0x0 ... 0xC:
>> +			break;
>> +		case 0xD:
>> +		case 0xE: /* Pentium M */
>> +			sizeof_field = sizeof(long);
>> +			debugctl_mask = (1<<6)|(1<<7);
>> +			break;
>> +		default:
>> +			sizeof_field = 8;
>> +			debugctl_mask = (1<<6)|(1<<7);
>> +			break;
>> +		}
>> +		break;
>> +	case 0xF:
>> +		switch (c->x86_model) {
>> +		case 0x0:
>> +		case 0x1:
>> +		case 0x2: /* Netburst */
>> +			sizeof_field = sizeof(long);
>> +			debugctl_mask = (1<<2)|(1<<3);
>> +			break;
>> +		default:
>> +			/* sorry, don't know about them */
>> +			break;
>> +		}
>> +		break;
>> +	default:
>> +		/* sorry, don't know about them */
>> +		break;
>> +	}
>> +}
>> +
>> +static inline void bts_enable(void)
>> +{
>> +	unsigned long debugctl;
>> +
>> +	rdmsrl(MSR_IA32_DEBUGCTLMSR, debugctl);
>> +	wrmsrl(MSR_IA32_DEBUGCTLMSR, debugctl | debugctl_mask);
>> +}
>> +
>> +static inline void bts_disable(void)
>> +{
>> +	unsigned long debugctl;
>> +
>> +	rdmsrl(MSR_IA32_DEBUGCTLMSR, debugctl);
>> +	wrmsrl(MSR_IA32_DEBUGCTLMSR, debugctl & ~debugctl_mask);
>> +}
>> +
>> +static void bts_trace_reset(struct trace_array *tr)
>> +{
>> +	int cpu;
>> +
>> +	tr->time_start = ftrace_now(tr->cpu);
>> +
>
>-- 
>ak@xxxxxxxxxxxxxxx
>
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