3  * Performance event support for the System z CPU-measurement Sampling Facility
27 /* Perf PMU definitions for the sampling facility */
29 #define PERF_EVENT_CPUM_SF		0xB0000UL /* Event: Basic-sampling */
30 #define PERF_EVENT_CPUM_SF_DIAG		0xBD000UL /* Event: Combined-sampling */
31 #define PERF_CPUM_SF_BASIC_MODE		0x0001	  /* Basic-sampling flag */
32 #define PERF_CPUM_SF_DIAG_MODE		0x0002	  /* Diagnostic-sampling flag */
33 #define PERF_CPUM_SF_FREQ_MODE		0x0008	  /* Sampling with frequency */
44  * At least one table is required for the sampling buffer structure.
65 /* Minimum and maximum sampling buffer sizes:
67  * This number represents the maximum size of the sampling buffer taking
69  * numbers apply to the basic-sampling function only.
71  * the diagnostic-sampling function is active.
73  * Sampling buffer size		Buffer characteristics
105 	/* CPU-measurement sampling information block */
107 	/* CPU-measurement sampling control block */
109 	struct sf_buffer sfb;	    /* Sampling buffer */
119 /* Sampling control helper functions */
160  * sf_disable() - Switch off sampling facility
171  * sf_buffer_available() - Check for an allocated sampling buffer
179  * deallocate sampling facility buffer
228  * Allocates new sample-data-blocks and adds them to the specified sampling
231  * Important: This modifies the sampling buffer and must be called when the
232  *	      sampling facility is disabled.
248 	/* Append to the existing sampling buffer, overwriting the table-link  in realloc_sampling_buffer()
256 	 * the sampling buffer origin.  in realloc_sampling_buffer()
306 	/* Link sampling buffer to its origin */  in realloc_sampling_buffer()
316  * Allocates and initializes a sampling buffer structure using the
403 	/* Calculate sampling buffers using 4K pages  in allocate_buffers()
405 	 *    1. The sampling size is 32 bytes for basic sampling. This size  in allocate_buffers()
407 	 *	 sampling uses auxlilary data buffer setup which provides the  in allocate_buffers()
421 	 *    3. Use the sampling frequency as input.  in allocate_buffers()
424 	 *	 SDBs to handle a higher sampling rate.  in allocate_buffers()
435 	/* If there is already a sampling buffer allocated, it is very likely  in allocate_buffers()
436 	 * that the sampling facility is enabled too.  If the event to be  in allocate_buffers()
437 	 * initialized requires a greater sampling buffer, the allocation must  in allocate_buffers()
438 	 * be postponed.  Changing the sampling buffer requires the sampling  in allocate_buffers()
459 	/* Use a percentage-based approach to extend the sampling facility  in compute_sfb_extent()
506 /* extend_sampling_buffer() - Extend sampling buffer
507  * @sfb:	Sampling buffer structure (for local CPU)
510  * Use this function to extend the sampling buffer based on the overflow counter
513  * Important: This function disables the sampling facility in order to safely
514  *	      change the sampling buffer structure.  Do not call this function
526 	/* Disable the sampling facility to reset any states and also  in extend_sampling_buffer()
531 	/* Extend the sampling buffer.  in extend_sampling_buffer()
642 	 * Obtain the PID from the basic-sampling data entry and  in cpumsf_output_event_pid()
674 		/* The min/max sampling rates specifies the valid range  in getrate()
682 		 * sampling rate does not exceed this value.  This also helps  in getrate()
694 /* The sampling information (si) contains information about the
695  * min/max sampling intervals and the CPU speed.  So calculate the
696  * correct sampling interval and avoid the whole period adjust
699  * Since the CPU Measurement sampling facility can not handle frequency
700  * calculate the sampling interval when frequency is specified using
705  * set to the correct sampling rate.
743 	/* Reserve CPU-measurement sampling facility */  in __hw_perf_event_init()
751 	/* Access per-CPU sampling information (query sampling info) */  in __hw_perf_event_init()
755 	 * sampling info from the current CPU, otherwise use event->cpu to  in __hw_perf_event_init()
757 	 * Later, cpuhw indicates whether to allocate sampling buffers for a  in __hw_perf_event_init()
766 		 * sampling structure for accessing the CPU-specific QSI.  in __hw_perf_event_init()
772 	/* Check sampling facility authorization and, if not authorized,  in __hw_perf_event_init()
782 		pr_warn("CPU Measurement Facility sampling is temporarily not available\n");  in __hw_perf_event_init()
787 	/* Always enable basic sampling */  in __hw_perf_event_init()
790 	/* Check if diagnostic sampling is requested.  Deny if the required  in __hw_perf_event_init()
791 	 * sampling authorization is missing.  in __hw_perf_event_init()
809 	/* Allocate the per-CPU sampling buffer using the CPU information  in __hw_perf_event_init()
811 	 * CPU (event->cpu == -1; or cpuhw == NULL), allocate sampling  in __hw_perf_event_init()
818 		/* Event is not pinned, allocate sampling buffer on  in __hw_perf_event_init()
829 	/* If PID/TID sampling is active, replace the default overflow  in __hw_perf_event_init()
830 	 * handler to extract and resolve the PIDs from the basic-sampling  in __hw_perf_event_init()
853 	/* No support for taken branch sampling */  in cpumsf_pmu_event_init()
865 		/* Support sampling of CPU cycles in addition to the  in cpumsf_pmu_event_init()
868 		 * sampling events only.  in cpumsf_pmu_event_init()
907 	/* Check whether to extent the sampling buffer.  in cpumsf_pmu_enable()
909 	 * Two conditions trigger an increase of the sampling buffer for a  in cpumsf_pmu_enable()
912 	 *    2. Sampling overflows that contribute to pending allocations.  in cpumsf_pmu_enable()
914 	 * Note that the extend_sampling_buffer() function disables the sampling  in cpumsf_pmu_enable()
915 	 * facility, but it can be fully re-enabled using sampling controls that  in cpumsf_pmu_enable()
929 	/* (Re)enable the PMU and sampling facility */  in cpumsf_pmu_enable()
932 		pr_err("Loading sampling controls failed: op 1 err %i\n", err);  in cpumsf_pmu_enable()
954 	/* Switch off sampling activation control */  in cpumsf_pmu_disable()
961 		pr_err("Loading sampling controls failed: op 2 err %i\n", err);  in cpumsf_pmu_disable()
967 	 * TEAR/DEAR values are valid only if the sampling facility is  in cpumsf_pmu_disable()
969 	 * for a disabled sampling facility because cpumsf_pmu_enable()  in cpumsf_pmu_disable()
1094  * Walks through a sample-data-block and collects sampling data entries that are
1095  * then pushed to the perf event subsystem.  Depending on the sampling function,
1096  * there can be either basic-sampling or combined-sampling data entries.  A
1097  * combined-sampling data entry consists of a basic- and a diagnostic-sampling
1098  * data entry.	The sampling function is determined by the flags in the perf
1099  * event hardware structure.  The function always works with a combined-sampling
1102  * Note that the implementation focuses on basic-sampling data entries and, if
1103  * such an entry is not valid, the entire combined-sampling data entry is
1145 			 * from a combined basic- and diagnostic-sampling.  in hw_collect_samples()
1146 			 * If only basic-sampling is then active, entries are  in hw_collect_samples()
1162 /* hw_perf_event_update() - Process sampling buffer
1166  * Processes the sampling buffer and create perf event samples.
1167  * The sampling buffer position are retrieved and saved in the TEAR_REG
1183 	 * AUX buffer is used when in diagnostic sampling mode.  in hw_perf_event_update()
1206 			 * is reached, extend the sampling buffer.  in hw_perf_event_update()
1294  * Finish sampling on the cpu. Called by cpumsf_pmu_del() with pmu
1327  * Start sampling on the CPU. Called by cpumsf_pmu_add() when an event
1489  * Measurement alert handler for diagnostic mode sampling.
1516 			       "diagnostic-sampling mode is full\n",  in hw_collect_aux()
1580  * aux_buffer_setup() - Setup AUX buffer for diagnostic mode sampling
1606 		       "maximum sampling buffer limit\n",  in aux_buffer_setup()
1611 		       "minimum sampling buffer limit\n",  in aux_buffer_setup()
1693 /* Check if the new sampling period/frequency is appropriate.
1708 		 * sampling structure for accessing the CPU-specific QSI.  in cpumsf_pmu_check_period()
1726 /* Activate sampling control.
1727  * Next call of pmu_enable() starts sampling.
1743 /* Deactivate sampling control.
1744  * Next call of pmu_enable() stops sampling.
1783 	/* Set up sampling controls.  Always program the sampling register  in cpumsf_pmu_add()
1785 	 * that is used by hw_perf_event_update() to store the sampling buffer  in cpumsf_pmu_add()
1797 	/* Ensure sampling functions are in the disabled state.  If disabled,  in cpumsf_pmu_add()
1798 	 * switch on sampling enable control. */  in cpumsf_pmu_add()
1851  * The availablitiy depends on the CPU_MF sampling facility authorization
1853  * time by the sampling facility device driver.
1855  * also turned off for diagnostic sampling.
1858  * level for diagnostic sampling and installs the attribute
1859  * file for diagnostic sampling if necessary.
1951 	/* Sampling authorization change request */  in cpumf_measurement_alert()
1962 	/* Invalid sampling buffer entry */  in cpumf_measurement_alert()
1964 		pr_err("A sampling buffer entry is incorrect (alert=%#x)\n",  in cpumf_measurement_alert()
2026 	pr_info("The sampling buffer limits have changed to: "  in param_set_sfb_size()
2039 	RS_INIT_FAILURE_BSDES	= 2,	/* Bad basic sampling size */
2046 	pr_err("Sampling facility support for perf is not available: "  in pr_cpumsf_err()
2070 		/* Sampling of diagnostic data authorized,  in init_cpum_sampling_pmu()