arch/x86/kernel/ds.c - linux/kernel/git/torvalds/linux - Git at Google

 /*
  * Debug Store support
  *
  * This provides a low-level interface to the hardware's Debug Store
  * feature that is used for last branch recording (LBR) and
  * precise-event based sampling (PEBS).
  *
  * Different architectures use a different DS layout/pointer size.
  * The below functions therefore work on a void*.
  *
  *
  * Since there is no user for PEBS, yet, only LBR (or branch
  * trace store, BTS) is supported.
  *
  *
  * Copyright (C) 2007 Intel Corporation.
  * Markus Metzger <markus.t.metzger@intel.com>, Dec 2007
  */

 #include <asm/ds.h>

 #include <linux/errno.h>
 #include <linux/string.h>
 #include <linux/slab.h>


 /*
  * Debug Store (DS) save area configuration (see Intel64 and IA32
  * Architectures Software Developer's Manual, section 18.5)
  *
  * The DS configuration consists of the following fields; different
  * architetures vary in the size of those fields.
  * - double-word aligned base linear address of the BTS buffer
  * - write pointer into the BTS buffer
  * - end linear address of the BTS buffer (one byte beyond the end of
  *   the buffer)
  * - interrupt pointer into BTS buffer
  *   (interrupt occurs when write pointer passes interrupt pointer)
  * - double-word aligned base linear address of the PEBS buffer
  * - write pointer into the PEBS buffer
  * - end linear address of the PEBS buffer (one byte beyond the end of
  *   the buffer)
  * - interrupt pointer into PEBS buffer
  *   (interrupt occurs when write pointer passes interrupt pointer)
  * - value to which counter is reset following counter overflow
  *
  * On later architectures, the last branch recording hardware uses
  * 64bit pointers even in 32bit mode.
  *
  *
  * Branch Trace Store (BTS) records store information about control
  * flow changes. They at least provide the following information:
  * - source linear address
  * - destination linear address
  *
  * Netburst supported a predicated bit that had been dropped in later
  * architectures. We do not suppor it.
  *
  *
  * In order to abstract from the actual DS and BTS layout, we describe
  * the access to the relevant fields.
  * Thanks to Andi Kleen for proposing this design.
  *
  * The implementation, however, is not as general as it might seem. In
  * order to stay somewhat simple and efficient, we assume an
  * underlying unsigned type (mostly a pointer type) and we expect the
  * field to be at least as big as that type.
  */

 /*
  * A special from_ip address to indicate that the BTS record is an
  * info record that needs to be interpreted or skipped.
  */
 #define BTS_ESCAPE_ADDRESS (-1)

 /*
  * A field access descriptor
  */
 struct access_desc {
 	unsigned char offset;
 	unsigned char size;
 };

 /*
  * The configuration for a particular DS/BTS hardware implementation.
  */
 struct ds_configuration {
 	/* the DS configuration */
 	unsigned char  sizeof_ds;
 	struct access_desc bts_buffer_base;
 	struct access_desc bts_index;
 	struct access_desc bts_absolute_maximum;
 	struct access_desc bts_interrupt_threshold;
 	/* the BTS configuration */
 	unsigned char  sizeof_bts;
 	struct access_desc from_ip;
 	struct access_desc to_ip;
 	/* BTS variants used to store additional information like
 	   timestamps */
 	struct access_desc info_type;
 	struct access_desc info_data;
 	unsigned long debugctl_mask;
 };

 /*
  * The global configuration used by the below accessor functions
  */
 static struct ds_configuration ds_cfg;

 /*
  * Accessor functions for some DS and BTS fields using the above
  * global ptrace_bts_cfg.
  */
 static inline unsigned long get_bts_buffer_base(char *base)
 {
 	return *(unsigned long *)(base + ds_cfg.bts_buffer_base.offset);
 }
 static inline void set_bts_buffer_base(char *base, unsigned long value)
 {
 	(*(unsigned long *)(base + ds_cfg.bts_buffer_base.offset)) = value;
 }
 static inline unsigned long get_bts_index(char *base)
 {
 	return *(unsigned long *)(base + ds_cfg.bts_index.offset);
 }
 static inline void set_bts_index(char *base, unsigned long value)
 {
 	(*(unsigned long *)(base + ds_cfg.bts_index.offset)) = value;
 }
 static inline unsigned long get_bts_absolute_maximum(char *base)
 {
 	return *(unsigned long *)(base + ds_cfg.bts_absolute_maximum.offset);
 }
 static inline void set_bts_absolute_maximum(char *base, unsigned long value)
 {
 	(*(unsigned long *)(base + ds_cfg.bts_absolute_maximum.offset)) = value;
 }
 static inline unsigned long get_bts_interrupt_threshold(char *base)
 {
 	return *(unsigned long *)(base + ds_cfg.bts_interrupt_threshold.offset);
 }
 static inline void set_bts_interrupt_threshold(char *base, unsigned long value)
 {
 	(*(unsigned long *)(base + ds_cfg.bts_interrupt_threshold.offset)) = value;
 }
 static inline unsigned long get_from_ip(char *base)
 {
 	return *(unsigned long *)(base + ds_cfg.from_ip.offset);
 }
 static inline void set_from_ip(char *base, unsigned long value)
 {
 	(*(unsigned long *)(base + ds_cfg.from_ip.offset)) = value;
 }
 static inline unsigned long get_to_ip(char *base)
 {
 	return *(unsigned long *)(base + ds_cfg.to_ip.offset);
 }
 static inline void set_to_ip(char *base, unsigned long value)
 {
 	(*(unsigned long *)(base + ds_cfg.to_ip.offset)) = value;
 }
 static inline unsigned char get_info_type(char *base)
 {
 	return *(unsigned char *)(base + ds_cfg.info_type.offset);
 }
 static inline void set_info_type(char *base, unsigned char value)
 {
 	(*(unsigned char *)(base + ds_cfg.info_type.offset)) = value;
 }
 static inline unsigned long get_info_data(char *base)
 {
 	return *(unsigned long *)(base + ds_cfg.info_data.offset);
 }
 static inline void set_info_data(char *base, unsigned long value)
 {
 	(*(unsigned long *)(base + ds_cfg.info_data.offset)) = value;
 }


 int ds_allocate(void **dsp, size_t bts_size_in_bytes)
 {
 	size_t bts_size_in_records;
 	unsigned long bts;
 	void *ds;

 	if (!ds_cfg.sizeof_ds || !ds_cfg.sizeof_bts)
 		return -EOPNOTSUPP;

 	if (bts_size_in_bytes < 0)
 		return -EINVAL;

 	bts_size_in_records =
 		bts_size_in_bytes / ds_cfg.sizeof_bts;
 	bts_size_in_bytes =
 		bts_size_in_records * ds_cfg.sizeof_bts;

 	if (bts_size_in_bytes <= 0)
 		return -EINVAL;

 	bts = (unsigned long)kzalloc(bts_size_in_bytes, GFP_KERNEL);

 	if (!bts)
 		return -ENOMEM;

 	ds = kzalloc(ds_cfg.sizeof_ds, GFP_KERNEL);

 	if (!ds) {
 		kfree((void *)bts);
 		return -ENOMEM;
 	}

 	set_bts_buffer_base(ds, bts);
 	set_bts_index(ds, bts);
 	set_bts_absolute_maximum(ds, bts + bts_size_in_bytes);
 	set_bts_interrupt_threshold(ds, bts + bts_size_in_bytes + 1);

 	*dsp = ds;
 	return 0;
 }

 int ds_free(void **dsp)
 {
 	if (*dsp)
 		kfree((void *)get_bts_buffer_base(*dsp));
 	kfree(*dsp);
 	*dsp = NULL;

 	return 0;
 }

 int ds_get_bts_size(void *ds)
 {
 	int size_in_bytes;

 	if (!ds_cfg.sizeof_ds || !ds_cfg.sizeof_bts)
 		return -EOPNOTSUPP;

 	if (!ds)
 		return 0;

 	size_in_bytes =
 		get_bts_absolute_maximum(ds) -
 		get_bts_buffer_base(ds);
 	return size_in_bytes;
 }

 int ds_get_bts_end(void *ds)
 {
 	int size_in_bytes = ds_get_bts_size(ds);

 	if (size_in_bytes <= 0)
 		return size_in_bytes;

 	return size_in_bytes / ds_cfg.sizeof_bts;
 }

 int ds_get_bts_index(void *ds)
 {
 	int index_offset_in_bytes;

 	if (!ds_cfg.sizeof_ds || !ds_cfg.sizeof_bts)
 		return -EOPNOTSUPP;

 	index_offset_in_bytes =
 		get_bts_index(ds) -
 		get_bts_buffer_base(ds);

 	return index_offset_in_bytes / ds_cfg.sizeof_bts;
 }

 int ds_set_overflow(void *ds, int method)
 {
 	switch (method) {
 	case DS_O_SIGNAL:
 		return -EOPNOTSUPP;
 	case DS_O_WRAP:
 		return 0;
 	default:
 		return -EINVAL;
 	}
 }

 int ds_get_overflow(void *ds)
 {
 	return DS_O_WRAP;
 }

 int ds_clear(void *ds)
 {
 	int bts_size = ds_get_bts_size(ds);
 	unsigned long bts_base;

 	if (bts_size <= 0)
 		return bts_size;

 	bts_base = get_bts_buffer_base(ds);
 	memset((void *)bts_base, 0, bts_size);

 	set_bts_index(ds, bts_base);
 	return 0;
 }

 int ds_read_bts(void *ds, int index, struct bts_struct *out)
 {
 	void *bts;

 	if (!ds_cfg.sizeof_ds || !ds_cfg.sizeof_bts)
 		return -EOPNOTSUPP;

 	if (index < 0)
 		return -EINVAL;

 	if (index >= ds_get_bts_size(ds))
 		return -EINVAL;

 	bts = (void *)(get_bts_buffer_base(ds) + (index * ds_cfg.sizeof_bts));

 	memset(out, 0, sizeof(*out));
 	if (get_from_ip(bts) == BTS_ESCAPE_ADDRESS) {
 		out->qualifier       = get_info_type(bts);
 		out->variant.jiffies = get_info_data(bts);
 	} else {
 		out->qualifier = BTS_BRANCH;
 		out->variant.lbr.from_ip = get_from_ip(bts);
 		out->variant.lbr.to_ip   = get_to_ip(bts);
 	}

 	return sizeof(*out);;
 }

 int ds_write_bts(void *ds, const struct bts_struct *in)
 {
 	unsigned long bts;

 	if (!ds_cfg.sizeof_ds || !ds_cfg.sizeof_bts)
 		return -EOPNOTSUPP;

 	if (ds_get_bts_size(ds) <= 0)
 		return -ENXIO;

 	bts = get_bts_index(ds);

 	memset((void *)bts, 0, ds_cfg.sizeof_bts);
 	switch (in->qualifier) {
 	case BTS_INVALID:
 		break;

 	case BTS_BRANCH:
 		set_from_ip((void *)bts, in->variant.lbr.from_ip);
 		set_to_ip((void *)bts, in->variant.lbr.to_ip);
 		break;

 	case BTS_TASK_ARRIVES:
 	case BTS_TASK_DEPARTS:
 		set_from_ip((void *)bts, BTS_ESCAPE_ADDRESS);
 		set_info_type((void *)bts, in->qualifier);
 		set_info_data((void *)bts, in->variant.jiffies);
 		break;

 	default:
 		return -EINVAL;
 	}

 	bts = bts + ds_cfg.sizeof_bts;
 	if (bts >= get_bts_absolute_maximum(ds))
 		bts = get_bts_buffer_base(ds);
 	set_bts_index(ds, bts);

 	return ds_cfg.sizeof_bts;
 }

 unsigned long ds_debugctl_mask(void)
 {
 	return ds_cfg.debugctl_mask;
 }

 #ifdef __i386__
 static const struct ds_configuration ds_cfg_netburst = {
 	.sizeof_ds = 9 * 4,
 	.bts_buffer_base = { 0, 4 },
 	.bts_index = { 4, 4 },
 	.bts_absolute_maximum = { 8, 4 },
 	.bts_interrupt_threshold = { 12, 4 },
 	.sizeof_bts = 3 * 4,
 	.from_ip = { 0, 4 },
 	.to_ip = { 4, 4 },
 	.info_type = { 4, 1 },
 	.info_data = { 8, 4 },
 	.debugctl_mask = (1<<2)|(1<<3)
 };

 static const struct ds_configuration ds_cfg_pentium_m = {
 	.sizeof_ds = 9 * 4,
 	.bts_buffer_base = { 0, 4 },
 	.bts_index = { 4, 4 },
 	.bts_absolute_maximum = { 8, 4 },
 	.bts_interrupt_threshold = { 12, 4 },
 	.sizeof_bts = 3 * 4,
 	.from_ip = { 0, 4 },
 	.to_ip = { 4, 4 },
 	.info_type = { 4, 1 },
 	.info_data = { 8, 4 },
 	.debugctl_mask = (1<<6)|(1<<7)
 };
 #endif /* _i386_ */

 static const struct ds_configuration ds_cfg_core2 = {
 	.sizeof_ds = 9 * 8,
 	.bts_buffer_base = { 0, 8 },
 	.bts_index = { 8, 8 },
 	.bts_absolute_maximum = { 16, 8 },
 	.bts_interrupt_threshold = { 24, 8 },
 	.sizeof_bts = 3 * 8,
 	.from_ip = { 0, 8 },
 	.to_ip = { 8, 8 },
 	.info_type = { 8, 1 },
 	.info_data = { 16, 8 },
 	.debugctl_mask = (1<<6)|(1<<7)|(1<<9)
 };

 static inline void
 ds_configure(const struct ds_configuration *cfg)
 {
 	ds_cfg = *cfg;
 }

 void __cpuinit ds_init_intel(struct cpuinfo_x86 *c)
 {
 	switch (c->x86) {
 	case 0x6:
 		switch (c->x86_model) {
 #ifdef __i386__
 		case 0xD:
 		case 0xE: /* Pentium M */
 			ds_configure(&ds_cfg_pentium_m);
 			break;
 #endif /* _i386_ */
 		case 0xF: /* Core2 */
 			ds_configure(&ds_cfg_core2);
 			break;
 		default:
 			/* sorry, don't know about them */
 			break;
 		}
 		break;
 	case 0xF:
 		switch (c->x86_model) {
 #ifdef __i386__
 		case 0x0:
 		case 0x1:
 		case 0x2: /* Netburst */
 			ds_configure(&ds_cfg_netburst);
 			break;
 #endif /* _i386_ */
 		default:
 			/* sorry, don't know about them */
 			break;
 		}
 		break;
 	default:
 		/* sorry, don't know about them */
 		break;
 	}
 }
	/*
	* Debug Store support
	*
	* This provides a low-level interface to the hardware's Debug Store
	* feature that is used for last branch recording (LBR) and
	* precise-event based sampling (PEBS).
	*
	* Different architectures use a different DS layout/pointer size.
	* The below functions therefore work on a void*.
	*
	*
	* Since there is no user for PEBS, yet, only LBR (or branch
	* trace store, BTS) is supported.
	*
	*
	* Copyright (C) 2007 Intel Corporation.
	* Markus Metzger <markus.t.metzger@intel.com>, Dec 2007
	*/

	#include <asm/ds.h>

	#include <linux/errno.h>
	#include <linux/string.h>
	#include <linux/slab.h>


	/*
	* Debug Store (DS) save area configuration (see Intel64 and IA32
	* Architectures Software Developer's Manual, section 18.5)
	*
	* The DS configuration consists of the following fields; different
	* architetures vary in the size of those fields.
	* - double-word aligned base linear address of the BTS buffer
	* - write pointer into the BTS buffer
	* - end linear address of the BTS buffer (one byte beyond the end of
	* the buffer)
	* - interrupt pointer into BTS buffer
	* (interrupt occurs when write pointer passes interrupt pointer)
	* - double-word aligned base linear address of the PEBS buffer
	* - write pointer into the PEBS buffer
	* - end linear address of the PEBS buffer (one byte beyond the end of
	* the buffer)
	* - interrupt pointer into PEBS buffer
	* (interrupt occurs when write pointer passes interrupt pointer)
	* - value to which counter is reset following counter overflow
	*
	* On later architectures, the last branch recording hardware uses
	* 64bit pointers even in 32bit mode.
	*
	*
	* Branch Trace Store (BTS) records store information about control
	* flow changes. They at least provide the following information:
	* - source linear address
	* - destination linear address
	*
	* Netburst supported a predicated bit that had been dropped in later
	* architectures. We do not suppor it.
	*
	*
	* In order to abstract from the actual DS and BTS layout, we describe
	* the access to the relevant fields.
	* Thanks to Andi Kleen for proposing this design.
	*
	* The implementation, however, is not as general as it might seem. In
	* order to stay somewhat simple and efficient, we assume an
	* underlying unsigned type (mostly a pointer type) and we expect the
	* field to be at least as big as that type.
	*/

	/*
	* A special from_ip address to indicate that the BTS record is an
	* info record that needs to be interpreted or skipped.
	*/
	#define BTS_ESCAPE_ADDRESS (-1)

	/*
	* A field access descriptor
	*/
	struct access_desc {
	unsigned char offset;
	unsigned char size;
	};

	/*
	* The configuration for a particular DS/BTS hardware implementation.
	*/
	struct ds_configuration {
	/* the DS configuration */
	unsigned char sizeof_ds;
	struct access_desc bts_buffer_base;
	struct access_desc bts_index;
	struct access_desc bts_absolute_maximum;
	struct access_desc bts_interrupt_threshold;
	/* the BTS configuration */
	unsigned char sizeof_bts;
	struct access_desc from_ip;
	struct access_desc to_ip;
	/* BTS variants used to store additional information like
	timestamps */
	struct access_desc info_type;
	struct access_desc info_data;
	unsigned long debugctl_mask;
	};

	/*
	* The global configuration used by the below accessor functions
	*/
	static struct ds_configuration ds_cfg;

	/*
	* Accessor functions for some DS and BTS fields using the above
	* global ptrace_bts_cfg.
	*/
	static inline unsigned long get_bts_buffer_base(char *base)
	{
	return (unsigned long )(base + ds_cfg.bts_buffer_base.offset);
	}
	static inline void set_bts_buffer_base(char *base, unsigned long value)
	{
	((unsigned long )(base + ds_cfg.bts_buffer_base.offset)) = value;
	}
	static inline unsigned long get_bts_index(char *base)
	{
	return (unsigned long )(base + ds_cfg.bts_index.offset);
	}
	static inline void set_bts_index(char *base, unsigned long value)
	{
	((unsigned long )(base + ds_cfg.bts_index.offset)) = value;
	}
	static inline unsigned long get_bts_absolute_maximum(char *base)
	{
	return (unsigned long )(base + ds_cfg.bts_absolute_maximum.offset);
	}
	static inline void set_bts_absolute_maximum(char *base, unsigned long value)
	{
	((unsigned long )(base + ds_cfg.bts_absolute_maximum.offset)) = value;
	}
	static inline unsigned long get_bts_interrupt_threshold(char *base)
	{
	return (unsigned long )(base + ds_cfg.bts_interrupt_threshold.offset);
	}
	static inline void set_bts_interrupt_threshold(char *base, unsigned long value)
	{
	((unsigned long )(base + ds_cfg.bts_interrupt_threshold.offset)) = value;
	}
	static inline unsigned long get_from_ip(char *base)
	{
	return (unsigned long )(base + ds_cfg.from_ip.offset);
	}
	static inline void set_from_ip(char *base, unsigned long value)
	{
	((unsigned long )(base + ds_cfg.from_ip.offset)) = value;
	}
	static inline unsigned long get_to_ip(char *base)
	{
	return (unsigned long )(base + ds_cfg.to_ip.offset);
	}
	static inline void set_to_ip(char *base, unsigned long value)
	{
	((unsigned long )(base + ds_cfg.to_ip.offset)) = value;
	}
	static inline unsigned char get_info_type(char *base)
	{
	return (unsigned char )(base + ds_cfg.info_type.offset);
	}
	static inline void set_info_type(char *base, unsigned char value)
	{
	((unsigned char )(base + ds_cfg.info_type.offset)) = value;
	}
	static inline unsigned long get_info_data(char *base)
	{
	return (unsigned long )(base + ds_cfg.info_data.offset);
	}
	static inline void set_info_data(char *base, unsigned long value)
	{
	((unsigned long )(base + ds_cfg.info_data.offset)) = value;
	}


	int ds_allocate(void **dsp, size_t bts_size_in_bytes)
	{
	size_t bts_size_in_records;
	unsigned long bts;
	void *ds;

	if (!ds_cfg.sizeof_ds \|\| !ds_cfg.sizeof_bts)
	return -EOPNOTSUPP;

	if (bts_size_in_bytes < 0)
	return -EINVAL;

	bts_size_in_records =
	bts_size_in_bytes / ds_cfg.sizeof_bts;
	bts_size_in_bytes =
	bts_size_in_records * ds_cfg.sizeof_bts;

	if (bts_size_in_bytes <= 0)
	return -EINVAL;

	bts = (unsigned long)kzalloc(bts_size_in_bytes, GFP_KERNEL);

	if (!bts)
	return -ENOMEM;

	ds = kzalloc(ds_cfg.sizeof_ds, GFP_KERNEL);

	if (!ds) {
	kfree((void *)bts);
	return -ENOMEM;
	}

	set_bts_buffer_base(ds, bts);
	set_bts_index(ds, bts);
	set_bts_absolute_maximum(ds, bts + bts_size_in_bytes);
	set_bts_interrupt_threshold(ds, bts + bts_size_in_bytes + 1);

	*dsp = ds;
	return 0;
	}

	int ds_free(void **dsp)
	{
	if (*dsp)
	kfree((void )get_bts_buffer_base(dsp));
	kfree(*dsp);
	*dsp = NULL;

	return 0;
	}

	int ds_get_bts_size(void *ds)
	{
	int size_in_bytes;

	if (!ds_cfg.sizeof_ds \|\| !ds_cfg.sizeof_bts)
	return -EOPNOTSUPP;

	if (!ds)
	return 0;

	size_in_bytes =
	get_bts_absolute_maximum(ds) -
	get_bts_buffer_base(ds);
	return size_in_bytes;
	}

	int ds_get_bts_end(void *ds)
	{
	int size_in_bytes = ds_get_bts_size(ds);

	if (size_in_bytes <= 0)
	return size_in_bytes;

	return size_in_bytes / ds_cfg.sizeof_bts;
	}

	int ds_get_bts_index(void *ds)
	{
	int index_offset_in_bytes;

	if (!ds_cfg.sizeof_ds \|\| !ds_cfg.sizeof_bts)
	return -EOPNOTSUPP;

	index_offset_in_bytes =
	get_bts_index(ds) -
	get_bts_buffer_base(ds);

	return index_offset_in_bytes / ds_cfg.sizeof_bts;
	}

	int ds_set_overflow(void *ds, int method)
	{
	switch (method) {
	case DS_O_SIGNAL:
	return -EOPNOTSUPP;
	case DS_O_WRAP:
	return 0;
	default:
	return -EINVAL;
	}
	}

	int ds_get_overflow(void *ds)
	{
	return DS_O_WRAP;
	}

	int ds_clear(void *ds)
	{
	int bts_size = ds_get_bts_size(ds);
	unsigned long bts_base;

	if (bts_size <= 0)
	return bts_size;

	bts_base = get_bts_buffer_base(ds);
	memset((void *)bts_base, 0, bts_size);

	set_bts_index(ds, bts_base);
	return 0;
	}

	int ds_read_bts(void ds, int index, struct bts_struct out)
	{
	void *bts;

	if (!ds_cfg.sizeof_ds \|\| !ds_cfg.sizeof_bts)
	return -EOPNOTSUPP;

	if (index < 0)
	return -EINVAL;

	if (index >= ds_get_bts_size(ds))
	return -EINVAL;

	bts = (void )(get_bts_buffer_base(ds) + (index ds_cfg.sizeof_bts));

	memset(out, 0, sizeof(*out));
	if (get_from_ip(bts) == BTS_ESCAPE_ADDRESS) {
	out->qualifier = get_info_type(bts);
	out->variant.jiffies = get_info_data(bts);
	} else {
	out->qualifier = BTS_BRANCH;
	out->variant.lbr.from_ip = get_from_ip(bts);
	out->variant.lbr.to_ip = get_to_ip(bts);
	}

	return sizeof(*out);;
	}

	int ds_write_bts(void ds, const struct bts_struct in)
	{
	unsigned long bts;

	if (!ds_cfg.sizeof_ds \|\| !ds_cfg.sizeof_bts)
	return -EOPNOTSUPP;

	if (ds_get_bts_size(ds) <= 0)
	return -ENXIO;

	bts = get_bts_index(ds);

	memset((void *)bts, 0, ds_cfg.sizeof_bts);
	switch (in->qualifier) {
	case BTS_INVALID:
	break;

	case BTS_BRANCH:
	set_from_ip((void *)bts, in->variant.lbr.from_ip);
	set_to_ip((void *)bts, in->variant.lbr.to_ip);
	break;

	case BTS_TASK_ARRIVES:
	case BTS_TASK_DEPARTS:
	set_from_ip((void *)bts, BTS_ESCAPE_ADDRESS);
	set_info_type((void *)bts, in->qualifier);
	set_info_data((void *)bts, in->variant.jiffies);
	break;

	default:
	return -EINVAL;
	}

	bts = bts + ds_cfg.sizeof_bts;
	if (bts >= get_bts_absolute_maximum(ds))
	bts = get_bts_buffer_base(ds);
	set_bts_index(ds, bts);

	return ds_cfg.sizeof_bts;
	}

	unsigned long ds_debugctl_mask(void)
	{
	return ds_cfg.debugctl_mask;
	}

	#ifdef __i386__
	static const struct ds_configuration ds_cfg_netburst = {
	.sizeof_ds = 9 * 4,
	.bts_buffer_base = { 0, 4 },
	.bts_index = { 4, 4 },
	.bts_absolute_maximum = { 8, 4 },
	.bts_interrupt_threshold = { 12, 4 },
	.sizeof_bts = 3 * 4,
	.from_ip = { 0, 4 },
	.to_ip = { 4, 4 },
	.info_type = { 4, 1 },
	.info_data = { 8, 4 },
	.debugctl_mask = (1<<2)\|(1<<3)
	};

	static const struct ds_configuration ds_cfg_pentium_m = {
	.sizeof_ds = 9 * 4,
	.bts_buffer_base = { 0, 4 },
	.bts_index = { 4, 4 },
	.bts_absolute_maximum = { 8, 4 },
	.bts_interrupt_threshold = { 12, 4 },
	.sizeof_bts = 3 * 4,
	.from_ip = { 0, 4 },
	.to_ip = { 4, 4 },
	.info_type = { 4, 1 },
	.info_data = { 8, 4 },
	.debugctl_mask = (1<<6)\|(1<<7)
	};
	#endif /* _i386_ */

	static const struct ds_configuration ds_cfg_core2 = {
	.sizeof_ds = 9 * 8,
	.bts_buffer_base = { 0, 8 },
	.bts_index = { 8, 8 },
	.bts_absolute_maximum = { 16, 8 },
	.bts_interrupt_threshold = { 24, 8 },
	.sizeof_bts = 3 * 8,
	.from_ip = { 0, 8 },
	.to_ip = { 8, 8 },
	.info_type = { 8, 1 },
	.info_data = { 16, 8 },
	.debugctl_mask = (1<<6)\|(1<<7)\|(1<<9)
	};

	static inline void
	ds_configure(const struct ds_configuration *cfg)
	{
	ds_cfg = *cfg;
	}

	void __cpuinit ds_init_intel(struct cpuinfo_x86 *c)
	{
	switch (c->x86) {
	case 0x6:
	switch (c->x86_model) {
	#ifdef __i386__
	case 0xD:
	case 0xE: /* Pentium M */
	ds_configure(&ds_cfg_pentium_m);
	break;
	#endif /* _i386_ */
	case 0xF: /* Core2 */
	ds_configure(&ds_cfg_core2);
	break;
	default:
	/* sorry, don't know about them */
	break;
	}
	break;
	case 0xF:
	switch (c->x86_model) {
	#ifdef __i386__
	case 0x0:
	case 0x1:
	case 0x2: /* Netburst */
	ds_configure(&ds_cfg_netburst);
	break;
	#endif /* _i386_ */
	default:
	/* sorry, don't know about them */
	break;
	}
	break;
	default:
	/* sorry, don't know about them */
	break;
	}
	}