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Commit bc44fb5f authored by Markus Metzger's avatar Markus Metzger Committed by Ingo Molnar
Browse files

x86, bts: detect size of DS fields 



Impact: more robust DS feature enumeration

Detect the size of the pointer-type fields in the DS area
configuration via the DTES64 features rather than based on
the cpuid.

Rename a variable to denote that size to reflect that it only
covers the pointer-type fields.

Add more boot-time diagnostics giving the detected size and
the sizes of BTS and PEBS records.

Use the size of the BTS/PEBS record to indicate that the
respective feature is not available (if the record size is zero).

Signed-off-by: default avatarMarkus Metzger <markus.t.metzger@intel.com>
LKML-Reference: <20090313104218.A30096@sedona.ch.intel.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 62a394eb

arch/x86/kernel/ds.c

+44 −40
Original line number Diff line number Diff line
@@ -39,7 +39,7 @@ struct ds_configuration { 
	/* the size of one pointer-typed field in the DS structure and

	   in the BTS and PEBS buffers in bytes;

	   this covers the first 8 DS fields related to buffer management. */

	unsigned char  sizeof_field;

	unsigned char  sizeof_ptr_field;

	/* the size of a BTS/PEBS record in bytes */

	unsigned char  sizeof_rec[2];

	/* a series of bit-masks to control various features indexed
@@ -142,14 +142,14 @@ enum ds_qualifier { 
static inline unsigned long ds_get(const unsigned char *base,

				   enum ds_qualifier qual, enum ds_field field)

{

	base += (ds_cfg.sizeof_field * (field + (4 * qual)));

	base += (ds_cfg.sizeof_ptr_field * (field + (4 * qual)));

	return *(unsigned long *)base;

}



static inline void ds_set(unsigned char *base, enum ds_qualifier qual,

			  enum ds_field field, unsigned long value)

{

	base += (ds_cfg.sizeof_field * (field + (4 * qual)));

	base += (ds_cfg.sizeof_ptr_field * (field + (4 * qual)));

	(*(unsigned long *)base) = value;

}
@@ -410,7 +410,7 @@ static int ds_write(struct ds_context *context, enum ds_qualifier qual, 
 * Later architectures use 64bit pointers throughout, whereas earlier

 * architectures use 32bit pointers in 32bit mode.

 *

 * We compute the base address for the first 8 fields based on:

 * We compute the base address for the fields based on:

 * - the field size stored in the DS configuration

 * - the relative field position

 *
@@ -441,13 +441,13 @@ enum bts_field { 


static inline unsigned long bts_get(const char *base, enum bts_field field)

{

	base += (ds_cfg.sizeof_field * field);

	base += (ds_cfg.sizeof_ptr_field * field);

	return *(unsigned long *)base;

}



static inline void bts_set(char *base, enum bts_field field, unsigned long val)

{

	base += (ds_cfg.sizeof_field * field);;

	base += (ds_cfg.sizeof_ptr_field * field);;

	(*(unsigned long *)base) = val;

}
@@ -593,6 +593,10 @@ static int ds_request(struct ds_tracer *tracer, struct ds_trace *trace, 
	struct ds_context *context;

	int error;



	error = -EOPNOTSUPP;

	if (!ds_cfg.sizeof_rec[qual])

		goto out;



	error = -EINVAL;

	if (!base)

		goto out;
@@ -635,10 +639,6 @@ struct bts_tracer *ds_request_bts(struct task_struct *task, 
	unsigned long irq;

	int error;



	error = -EOPNOTSUPP;

	if (!ds_cfg.ctl[dsf_bts])

		goto out;



	/* buffer overflow notification is not yet implemented */

	error = -EOPNOTSUPP;

	if (ovfl)
@@ -848,7 +848,8 @@ const struct pebs_trace *ds_read_pebs(struct pebs_tracer *tracer) 


	ds_read_config(tracer->ds.context, &tracer->trace.ds, ds_pebs);

	tracer->trace.reset_value =

		*(u64 *)(tracer->ds.context->ds + (ds_cfg.sizeof_field * 8));

		*(u64 *)(tracer->ds.context->ds +

			 (ds_cfg.sizeof_ptr_field * 8));



	return &tracer->trace;

}
@@ -884,7 +885,8 @@ int ds_set_pebs_reset(struct pebs_tracer *tracer, u64 value) 
	if (!tracer)

		return -EINVAL;



	*(u64 *)(tracer->ds.context->ds + (ds_cfg.sizeof_field * 8)) = value;

	*(u64 *)(tracer->ds.context->ds +

		 (ds_cfg.sizeof_ptr_field * 8)) = value;



	return 0;

}
@@ -894,52 +896,54 @@ static const struct ds_configuration ds_cfg_netburst = { 
	.ctl[dsf_bts]		= (1 << 2) | (1 << 3),

	.ctl[dsf_bts_kernel]	= (1 << 5),

	.ctl[dsf_bts_user]	= (1 << 6),



	.sizeof_field		= sizeof(long),

	.sizeof_rec[ds_bts]	= sizeof(long) * 3,

#ifdef __i386__

	.sizeof_rec[ds_pebs]	= sizeof(long) * 10,

#else

	.sizeof_rec[ds_pebs]	= sizeof(long) * 18,

#endif

};

static const struct ds_configuration ds_cfg_pentium_m = {

	.name = "Pentium M",

	.ctl[dsf_bts]		= (1 << 6) | (1 << 7),



	.sizeof_field		= sizeof(long),

	.sizeof_rec[ds_bts]	= sizeof(long) * 3,

#ifdef __i386__

	.sizeof_rec[ds_pebs]	= sizeof(long) * 10,

#else

	.sizeof_rec[ds_pebs]	= sizeof(long) * 18,

#endif

};

static const struct ds_configuration ds_cfg_core2_atom = {

	.name = "Core 2/Atom",

	.ctl[dsf_bts]		= (1 << 6) | (1 << 7),

	.ctl[dsf_bts_kernel]	= (1 << 9),

	.ctl[dsf_bts_user]	= (1 << 10),



	.sizeof_field		= 8,

	.sizeof_rec[ds_bts]	= 8 * 3,

	.sizeof_rec[ds_pebs]	= 8 * 18,

};



static void

ds_configure(const struct ds_configuration *cfg)

ds_configure(const struct ds_configuration *cfg,

	     struct cpuinfo_x86 *cpu)

{

	unsigned long nr_pebs_fields = 0;



	printk(KERN_INFO "[ds] using %s configuration\n", cfg->name);



#ifdef __i386__

	nr_pebs_fields = 10;

#else

	nr_pebs_fields = 18;

#endif



	memset(&ds_cfg, 0, sizeof(ds_cfg));

	ds_cfg = *cfg;



	printk(KERN_INFO "[ds] using %s configuration\n", ds_cfg.name);

	ds_cfg.sizeof_ptr_field =

		(cpu_has(cpu, X86_FEATURE_DTES64) ? 8 : 4);



	if (!cpu_has_bts) {

		ds_cfg.ctl[dsf_bts] = 0;

	ds_cfg.sizeof_rec[ds_bts]  = ds_cfg.sizeof_ptr_field * 3;

	ds_cfg.sizeof_rec[ds_pebs] = ds_cfg.sizeof_ptr_field * nr_pebs_fields;



	if (!cpu_has(cpu, X86_FEATURE_BTS)) {

		ds_cfg.sizeof_rec[ds_bts] = 0;

		printk(KERN_INFO "[ds] bts not available\n");

	}

	if (!cpu_has_pebs)

	if (!cpu_has(cpu, X86_FEATURE_PEBS)) {

		ds_cfg.sizeof_rec[ds_pebs] = 0;

		printk(KERN_INFO "[ds] pebs not available\n");

	}



	printk(KERN_INFO "[ds] sizes: address: %u bit, ",

	       8 * ds_cfg.sizeof_ptr_field);

	printk("bts/pebs record: %u/%u bytes\n",

	       ds_cfg.sizeof_rec[ds_bts], ds_cfg.sizeof_rec[ds_pebs]);



	WARN_ON_ONCE(MAX_SIZEOF_DS < (12 * ds_cfg.sizeof_field));

}
@@ -951,12 +955,12 @@ void __cpuinit ds_init_intel(struct cpuinfo_x86 *c) 
		switch (c->x86_model) {

		case 0x9:

		case 0xd: /* Pentium M */

			ds_configure(&ds_cfg_pentium_m);

			ds_configure(&ds_cfg_pentium_m, c);

			break;

		case 0xf:

		case 0x17: /* Core2 */

		case 0x1c: /* Atom */

			ds_configure(&ds_cfg_core2_atom);

			ds_configure(&ds_cfg_core2_atom, c);

			break;

		case 0x1a: /* i7 */

		default:
@@ -969,7 +973,7 @@ void __cpuinit ds_init_intel(struct cpuinfo_x86 *c) 
		case 0x0:

		case 0x1:

		case 0x2: /* Netburst */

			ds_configure(&ds_cfg_netburst);

			ds_configure(&ds_cfg_netburst, c);

			break;

		default:

			/* sorry, don't know about them */