From: "Metzger, Markus T" <markus.t.metzger@intel.com>
To: Andi Kleen <andi@firstfloor.org>
CC: "hpa@zytor.com" <hpa@zytor.com>,
       "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
       "mingo@elte.hu" <mingo@elte.hu>,
       "tglx@linutronix.de" <tglx@linutronix.de>,
       "markus.t.metzger@gmail.com" <markus.t.metzger@gmail.com>,
       "roland@redhat.com" <roland@redhat.com>,
       "akpm@linux-foundation.org" <akpm@linux-foundation.org>,
       "mtk.manpages@gmail.com" <mtk.manpages@gmail.com>,
       "eranian@googlemail.com" <eranian@googlemail.com>,
       "Villacis, Juan" <juan.villacis@intel.com>
Date: Tue, 25 Nov 2008 10:25:14 +0000
Subject: RE: [patch 9/9] x86, bts, ftrace: a BTS ftrace plug-in prototype
Thread-Topic: [patch 9/9] x86, bts, ftrace: a BTS ftrace plug-in prototype
Thread-Index: AclO5mWQbbu4Yl4IRuiGJBnW2RCxhQAAJ1Iw
Message-ID: <928CFBE8E7CB0040959E56B4EA41A77E08F3C320@irsmsx504.ger.corp.intel.com>
References: <20081125092415.A31432@sedona.ch.intel.com>
 <87hc5wcdwu.fsf@basil.nowhere.org>
In-Reply-To: <87hc5wcdwu.fsf@basil.nowhere.org>
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>-----Original Message-----
>From: Andi Kleen [mailto:andi@firstfloor.org] 
>Sent: Dienstag, 25. November 2008 11:13
>To: Metzger, Markus T

>Markus Metzger <markus.t.metzger@intel.com> 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@linux.intel.com
>
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