[deliverable/linux.git] / arch / x86 / include / asm / ds.h

/*
 * Debug Store (DS) support
 *
 * This provides a low-level interface to the hardware's Debug Store
 * feature that is used for branch trace store (BTS) and
 * precise-event based sampling (PEBS).
 *
 * It manages:
 * - per-thread and per-cpu allocation of BTS and PEBS
 * - buffer memory allocation (optional)
 * - buffer overflow handling
 * - buffer access
 *
 * It assumes:
 * - get_task_struct on all parameter tasks
 * - current is allowed to trace parameter tasks
 *
 *
 * Copyright (C) 2007-2008 Intel Corporation.
 * Markus Metzger <markus.t.metzger@intel.com>, 2007-2008
 */

#ifndef _ASM_X86_DS_H
#define _ASM_X86_DS_H

#ifdef CONFIG_X86_DS

#include <linux/types.h>
#include <linux/init.h>


struct task_struct;

/*
 * Request BTS or PEBS
 *
 * Due to alignement constraints, the actual buffer may be slightly
 * smaller than the requested or provided buffer.
 *
 * Returns 0 on success; -Eerrno otherwise
 *
 * task: the task to request recording for;
 *       NULL for per-cpu recording on the current cpu
 * base: the base pointer for the (non-pageable) buffer;
 *       NULL if buffer allocation requested
 * size: the size of the requested or provided buffer
 * ovfl: pointer to a function to be called on buffer overflow;
 *       NULL if cyclic buffer requested
 */
typedef void (*ds_ovfl_callback_t)(struct task_struct *);
extern int ds_request_bts(struct task_struct *task, void *base, size_t size,
			  ds_ovfl_callback_t ovfl);
extern int ds_request_pebs(struct task_struct *task, void *base, size_t size,
			   ds_ovfl_callback_t ovfl);

/*
 * Release BTS or PEBS resources
 *
 * Frees buffers allocated on ds_request.
 *
 * Returns 0 on success; -Eerrno otherwise
 *
 * task: the task to release resources for;
 *       NULL to release resources for the current cpu
 */
extern int ds_release_bts(struct task_struct *task);
extern int ds_release_pebs(struct task_struct *task);

/*
 * Return the (array) index of the write pointer.
 * (assuming an array of BTS/PEBS records)
 *
 * Returns -Eerrno on error
 *
 * task: the task to access;
 *       NULL to access the current cpu
 * pos (out): if not NULL, will hold the result
 */
extern int ds_get_bts_index(struct task_struct *task, size_t *pos);
extern int ds_get_pebs_index(struct task_struct *task, size_t *pos);

/*
 * Return the (array) index one record beyond the end of the array.
 * (assuming an array of BTS/PEBS records)
 *
 * Returns -Eerrno on error
 *
 * task: the task to access;
 *       NULL to access the current cpu
 * pos (out): if not NULL, will hold the result
 */
extern int ds_get_bts_end(struct task_struct *task, size_t *pos);
extern int ds_get_pebs_end(struct task_struct *task, size_t *pos);

/*
 * Provide a pointer to the BTS/PEBS record at parameter index.
 * (assuming an array of BTS/PEBS records)
 *
 * The pointer points directly into the buffer. The user is
 * responsible for copying the record.
 *
 * Returns the size of a single record on success; -Eerrno on error
 *
 * task: the task to access;
 *       NULL to access the current cpu
 * index: the index of the requested record
 * record (out): pointer to the requested record
 */
extern int ds_access_bts(struct task_struct *task,
			 size_t index, const void **record);
extern int ds_access_pebs(struct task_struct *task,
			  size_t index, const void **record);

/*
 * Write one or more BTS/PEBS records at the write pointer index and
 * advance the write pointer.
 *
 * If size is not a multiple of the record size, trailing bytes are
 * zeroed out.
 *
 * May result in one or more overflow notifications.
 *
 * If called during overflow handling, that is, with index >=
 * interrupt threshold, the write will wrap around.
 *
 * An overflow notification is given if and when the interrupt
 * threshold is reached during or after the write.
 *
 * Returns the number of bytes written or -Eerrno.
 *
 * task: the task to access;
 *       NULL to access the current cpu
 * buffer: the buffer to write
 * size: the size of the buffer
 */
extern int ds_write_bts(struct task_struct *task,
			const void *buffer, size_t size);
extern int ds_write_pebs(struct task_struct *task,
			 const void *buffer, size_t size);

/*
 * Same as ds_write_bts/pebs, but omit ownership checks.
 *
 * This is needed to have some other task than the owner of the
 * BTS/PEBS buffer or the parameter task itself write into the
 * respective buffer.
 */
extern int ds_unchecked_write_bts(struct task_struct *task,
				  const void *buffer, size_t size);
extern int ds_unchecked_write_pebs(struct task_struct *task,
				   const void *buffer, size_t size);

/*
 * Reset the write pointer of the BTS/PEBS buffer.
 *
 * Returns 0 on success; -Eerrno on error
 *
 * task: the task to access;
 *       NULL to access the current cpu
 */
extern int ds_reset_bts(struct task_struct *task);
extern int ds_reset_pebs(struct task_struct *task);

/*
 * Clear the BTS/PEBS buffer and reset the write pointer.
 * The entire buffer will be zeroed out.
 *
 * Returns 0 on success; -Eerrno on error
 *
 * task: the task to access;
 *       NULL to access the current cpu
 */
extern int ds_clear_bts(struct task_struct *task);
extern int ds_clear_pebs(struct task_struct *task);

/*
 * Provide the PEBS counter reset value.
 *
 * Returns 0 on success; -Eerrno on error
 *
 * task: the task to access;
 *       NULL to access the current cpu
 * value (out): the counter reset value
 */
extern int ds_get_pebs_reset(struct task_struct *task, u64 *value);

/*
 * Set the PEBS counter reset value.
 *
 * Returns 0 on success; -Eerrno on error
 *
 * task: the task to access;
 *       NULL to access the current cpu
 * value: the new counter reset value
 */
extern int ds_set_pebs_reset(struct task_struct *task, u64 value);

/*
 * Initialization
 */
struct cpuinfo_x86;
extern void __cpuinit ds_init_intel(struct cpuinfo_x86 *);


/*
 * The DS context - part of struct thread_struct.
 */
struct ds_context {
	/* pointer to the DS configuration; goes into MSR_IA32_DS_AREA */
	unsigned char *ds;
	/* the owner of the BTS and PEBS configuration, respectively */
	struct task_struct *owner[2];
	/* buffer overflow notification function for BTS and PEBS */
	ds_ovfl_callback_t callback[2];
	/* the original buffer address */
	void *buffer[2];
	/* the number of allocated pages for on-request allocated buffers */
	unsigned int pages[2];
	/* use count */
	unsigned long count;
	/* a pointer to the context location inside the thread_struct
	 * or the per_cpu context array */
	struct ds_context **this;
	/* a pointer to the task owning this context, or NULL, if the
	 * context is owned by a cpu */
	struct task_struct *task;
};

/* called by exit_thread() to free leftover contexts */
extern void ds_free(struct ds_context *context);

#else /* CONFIG_X86_DS */

#define ds_init_intel(config) do {} while (0)

#endif /* CONFIG_X86_DS */
#endif /* _ASM_X86_DS_H */
Commit	Line	Data
eee3af4a MM	1	/*
	2	* Debug Store (DS) support
	3	*
	4	* This provides a low-level interface to the hardware's Debug Store
93fa7636	5	* feature that is used for branch trace store (BTS) and
eee3af4a MM	6	* precise-event based sampling (PEBS).
eee3af4a MM	7	*
93fa7636 MM	8	* It manages:
	9	* - per-thread and per-cpu allocation of BTS and PEBS
	10	* - buffer memory allocation (optional)
	11	* - buffer overflow handling
	12	* - buffer access
eee3af4a	13	*
93fa7636 MM	14	* It assumes:
	15	* - get_task_struct on all parameter tasks
	16	* - current is allowed to trace parameter tasks
eee3af4a	17	*
eee3af4a	18	*
93fa7636 MM	19	* Copyright (C) 2007-2008 Intel Corporation.
93fa7636 MM	20	* Markus Metzger <markus.t.metzger@intel.com>, 2007-2008
eee3af4a MM	21	*/
eee3af4a MM	22
1965aae3 PA	23	#ifndef _ASM_X86_DS_H
1965aae3 PA	24	#define _ASM_X86_DS_H
eee3af4a	25
93fa7636 MM	26	#ifdef CONFIG_X86_DS
93fa7636 MM	27
eee3af4a MM	28	#include <linux/types.h>
	29	#include <linux/init.h>
	30
eee3af4a	31
93fa7636	32	struct task_struct;
eee3af4a	33
93fa7636 MM	34	/*
	35	* Request BTS or PEBS
	36	*
	37	* Due to alignement constraints, the actual buffer may be slightly
	38	* smaller than the requested or provided buffer.
eee3af4a	39	*
93fa7636 MM	40	* Returns 0 on success; -Eerrno otherwise
	41	*
	42	* task: the task to request recording for;
	43	* NULL for per-cpu recording on the current cpu
	44	* base: the base pointer for the (non-pageable) buffer;
	45	* NULL if buffer allocation requested
	46	* size: the size of the requested or provided buffer
	47	* ovfl: pointer to a function to be called on buffer overflow;
	48	* NULL if cyclic buffer requested
eee3af4a	49	*/
93fa7636 MM	50	typedef void (ds_ovfl_callback_t)(struct task_struct );
	51	extern int ds_request_bts(struct task_struct task, void base, size_t size,
	52	ds_ovfl_callback_t ovfl);
	53	extern int ds_request_pebs(struct task_struct task, void base, size_t size,
	54	ds_ovfl_callback_t ovfl);
	55
	56	/*
	57	* Release BTS or PEBS resources
	58	*
	59	* Frees buffers allocated on ds_request.
	60	*
	61	* Returns 0 on success; -Eerrno otherwise
	62	*
	63	* task: the task to release resources for;
	64	* NULL to release resources for the current cpu
	65	*/
	66	extern int ds_release_bts(struct task_struct *task);
	67	extern int ds_release_pebs(struct task_struct *task);
	68
	69	/*
	70	* Return the (array) index of the write pointer.
	71	* (assuming an array of BTS/PEBS records)
	72	*
	73	* Returns -Eerrno on error
	74	*
	75	* task: the task to access;
	76	* NULL to access the current cpu
	77	* pos (out): if not NULL, will hold the result
	78	*/
	79	extern int ds_get_bts_index(struct task_struct task, size_t pos);
	80	extern int ds_get_pebs_index(struct task_struct task, size_t pos);
	81
	82	/*
	83	* Return the (array) index one record beyond the end of the array.
	84	* (assuming an array of BTS/PEBS records)
	85	*
	86	* Returns -Eerrno on error
	87	*
	88	* task: the task to access;
	89	* NULL to access the current cpu
	90	* pos (out): if not NULL, will hold the result
	91	*/
	92	extern int ds_get_bts_end(struct task_struct task, size_t pos);
	93	extern int ds_get_pebs_end(struct task_struct task, size_t pos);
	94
	95	/*
	96	* Provide a pointer to the BTS/PEBS record at parameter index.
	97	* (assuming an array of BTS/PEBS records)
	98	*
	99	* The pointer points directly into the buffer. The user is
	100	* responsible for copying the record.
	101	*
	102	* Returns the size of a single record on success; -Eerrno on error
	103	*
	104	* task: the task to access;
	105	* NULL to access the current cpu
	106	* index: the index of the requested record
	107	* record (out): pointer to the requested record
	108	*/
	109	extern int ds_access_bts(struct task_struct *task,
	110	size_t index, const void **record);
	111	extern int ds_access_pebs(struct task_struct *task,
	112	size_t index, const void **record);
	113
114	/*
115	* Write one or more BTS/PEBS records at the write pointer index and
116	* advance the write pointer.
117	*
118	* If size is not a multiple of the record size, trailing bytes are
119	* zeroed out.
120	*
121	* May result in one or more overflow notifications.
122	*
123	* If called during overflow handling, that is, with index >=
124	* interrupt threshold, the write will wrap around.
125	*
126	* An overflow notification is given if and when the interrupt
127	* threshold is reached during or after the write.
128	*
129	* Returns the number of bytes written or -Eerrno.
130	*
131	* task: the task to access;
132	* NULL to access the current cpu
133	* buffer: the buffer to write
134	* size: the size of the buffer
135	*/
136	extern int ds_write_bts(struct task_struct *task,
137	const void *buffer, size_t size);
138	extern int ds_write_pebs(struct task_struct *task,
139	const void *buffer, size_t size);
140
141	/*
142	* Same as ds_write_bts/pebs, but omit ownership checks.
143	*
144	* This is needed to have some other task than the owner of the
145	* BTS/PEBS buffer or the parameter task itself write into the
146	* respective buffer.
147	*/
148	extern int ds_unchecked_write_bts(struct task_struct *task,
149	const void *buffer, size_t size);
150	extern int ds_unchecked_write_pebs(struct task_struct *task,
151	const void *buffer, size_t size);
152
153	/*
154	* Reset the write pointer of the BTS/PEBS buffer.
155	*
156	* Returns 0 on success; -Eerrno on error
157	*
158	* task: the task to access;
159	* NULL to access the current cpu
160	*/
161	extern int ds_reset_bts(struct task_struct *task);
162	extern int ds_reset_pebs(struct task_struct *task);
163
164	/*
165	* Clear the BTS/PEBS buffer and reset the write pointer.
166	* The entire buffer will be zeroed out.
167	*
168	* Returns 0 on success; -Eerrno on error
169	*
170	* task: the task to access;
171	* NULL to access the current cpu
172	*/
173	extern int ds_clear_bts(struct task_struct *task);
174	extern int ds_clear_pebs(struct task_struct *task);
175
176	/*
177	* Provide the PEBS counter reset value.
178	*
179	* Returns 0 on success; -Eerrno on error
180	*
181	* task: the task to access;
182	* NULL to access the current cpu
183	* value (out): the counter reset value
184	*/
185	extern int ds_get_pebs_reset(struct task_struct task, u64 value);
186
187	/*
188	* Set the PEBS counter reset value.
189	*
190	* Returns 0 on success; -Eerrno on error
191	*
192	* task: the task to access;
193	* NULL to access the current cpu
194	* value: the new counter reset value
195	*/
196	extern int ds_set_pebs_reset(struct task_struct *task, u64 value);
197
198	/*
199	* Initialization
200	*/
201	struct cpuinfo_x86;
202	extern void __cpuinit ds_init_intel(struct cpuinfo_x86 *);
203
204
eee3af4a	205
93fa7636 MM	206	/*
	207	* The DS context - part of struct thread_struct.
	208	*/
	209	struct ds_context {
	210	/* pointer to the DS configuration; goes into MSR_IA32_DS_AREA */
	211	unsigned char *ds;
	212	/* the owner of the BTS and PEBS configuration, respectively */
	213	struct task_struct *owner[2];
	214	/* buffer overflow notification function for BTS and PEBS */
	215	ds_ovfl_callback_t callback[2];
	216	/* the original buffer address */
	217	void *buffer[2];
	218	/* the number of allocated pages for on-request allocated buffers */
	219	unsigned int pages[2];
	220	/* use count */
	221	unsigned long count;
	222	/* a pointer to the context location inside the thread_struct
	223	* or the per_cpu context array */
	224	struct ds_context **this;
	225	/* a pointer to the task owning this context, or NULL, if the
	226	* context is owned by a cpu */
	227	struct task_struct *task;
eee3af4a MM	228	};
eee3af4a MM	229
93fa7636 MM	230	/* called by exit_thread() to free leftover contexts */
	231	extern void ds_free(struct ds_context *context);
	232
	233	#else /* CONFIG_X86_DS */
	234
	235	#define ds_init_intel(config) do {} while (0)
eee3af4a	236
93fa7636	237	#endif /* CONFIG_X86_DS */
1965aae3	238	#endif /* _ASM_X86_DS_H */