/* * 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 overflow handling (to be done) * - buffer access * * It assumes: * - get_task_struct on all traced tasks * - current is allowed to trace tasks * * * Copyright (C) 2007-2008 Intel Corporation. * Markus Metzger , 2007-2008 */ #ifndef _ASM_X86_DS_H #define _ASM_X86_DS_H #include #include #include #ifdef CONFIG_X86_DS struct task_struct; struct ds_tracer; struct bts_tracer; struct pebs_tracer; typedef void (*bts_ovfl_callback_t)(struct bts_tracer *); typedef void (*pebs_ovfl_callback_t)(struct pebs_tracer *); /* * Request BTS or PEBS * * Due to alignement constraints, the actual buffer may be slightly * smaller than the requested or provided buffer. * * Returns a pointer to a tracer structure on success, or * ERR_PTR(errcode) on failure. * * The interrupt threshold is independent from the overflow callback * to allow users to use their own overflow interrupt handling mechanism. * * 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; * size: the size of the provided buffer in bytes * ovfl: pointer to a function to be called on buffer overflow; * NULL if cyclic buffer requested * th: the interrupt threshold in records from the end of the buffer; * -1 if no interrupt threshold is requested. */ extern struct bts_tracer *ds_request_bts(struct task_struct *task, void *base, size_t size, bts_ovfl_callback_t ovfl, size_t th); extern struct pebs_tracer *ds_request_pebs(struct task_struct *task, void *base, size_t size, pebs_ovfl_callback_t ovfl, size_t th); /* * Release BTS or PEBS resources * * Returns 0 on success; -Eerrno otherwise * * tracer: the tracer handle returned from ds_request_~() */ extern int ds_release_bts(struct bts_tracer *tracer); extern int ds_release_pebs(struct pebs_tracer *tracer); /* * Get the (array) index of the write pointer. * (assuming an array of BTS/PEBS records) * * Returns 0 on success; -Eerrno on error * * tracer: the tracer handle returned from ds_request_~() * pos (out): will hold the result */ extern int ds_get_bts_index(struct bts_tracer *tracer, size_t *pos); extern int ds_get_pebs_index(struct pebs_tracer *tracer, size_t *pos); /* * Get the (array) index one record beyond the end of the array. * (assuming an array of BTS/PEBS records) * * Returns 0 on success; -Eerrno on error * * tracer: the tracer handle returned from ds_request_~() * pos (out): will hold the result */ extern int ds_get_bts_end(struct bts_tracer *tracer, size_t *pos); extern int ds_get_pebs_end(struct pebs_tracer *tracer, 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 * * tracer: the tracer handle returned from ds_request_~() * index: the index of the requested record * record (out): pointer to the requested record */ extern int ds_access_bts(struct bts_tracer *tracer, size_t index, const void **record); extern int ds_access_pebs(struct pebs_tracer *tracer, 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. * * tracer: the tracer handle returned from ds_request_~() * buffer: the buffer to write * size: the size of the buffer */ extern int ds_write_bts(struct bts_tracer *tracer, const void *buffer, size_t size); extern int ds_write_pebs(struct pebs_tracer *tracer, const void *buffer, size_t size); /* * Reset the write pointer of the BTS/PEBS buffer. * * Returns 0 on success; -Eerrno on error * * tracer: the tracer handle returned from ds_request_~() */ extern int ds_reset_bts(struct bts_tracer *tracer); extern int ds_reset_pebs(struct pebs_tracer *tracer); /* * Clear the BTS/PEBS buffer and reset the write pointer. * The entire buffer will be zeroed out. * * Returns 0 on success; -Eerrno on error * * tracer: the tracer handle returned from ds_request_~() */ extern int ds_clear_bts(struct bts_tracer *tracer); extern int ds_clear_pebs(struct pebs_tracer *tracer); /* * Provide the PEBS counter reset value. * * Returns 0 on success; -Eerrno on error * * tracer: the tracer handle returned from ds_request_pebs() * value (out): the counter reset value */ extern int ds_get_pebs_reset(struct pebs_tracer *tracer, u64 *value); /* * Set the PEBS counter reset value. * * Returns 0 on success; -Eerrno on error * * tracer: the tracer handle returned from ds_request_pebs() * value: the new counter reset value */ extern int ds_set_pebs_reset(struct pebs_tracer *tracer, u64 value); /* * Initialization */ struct cpuinfo_x86; extern void __cpuinit ds_init_intel(struct cpuinfo_x86 *); /* * The DS context - part of struct thread_struct. */ #define MAX_SIZEOF_DS (12 * 8) struct ds_context { /* pointer to the DS configuration; goes into MSR_IA32_DS_AREA */ unsigned char ds[MAX_SIZEOF_DS]; /* the owner of the BTS and PEBS configuration, respectively */ struct ds_tracer *owner[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 */ struct cpuinfo_x86; static inline void __cpuinit ds_init_intel(struct cpuinfo_x86 *ignored) {} #endif /* CONFIG_X86_DS */ #endif /* _ASM_X86_DS_H */