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
202 			/* If the origin is reached, sampling buffer is freed */  in free_sampling_buffer()
240  * Allocates new sample-data-blocks and adds them to the specified sampling
243  * Important: This modifies the sampling buffer and must be called when the
244  *	      sampling facility is disabled.
260 	/* Append to the existing sampling buffer, overwriting the table-link  in realloc_sampling_buffer()
268 	 * the sampling buffer origin.  in realloc_sampling_buffer()
318 	/* Link sampling buffer to its origin */  in realloc_sampling_buffer()
328  * Allocates and initializes a sampling buffer structure using the
415 	/* Calculate sampling buffers using 4K pages  in allocate_buffers()
417 	 *    1. The sampling size is 32 bytes for basic sampling. This size  in allocate_buffers()
419 	 *	 sampling uses auxlilary data buffer setup which provides the  in allocate_buffers()
433 	 *    3. Use the sampling frequency as input.  in allocate_buffers()
436 	 *	 SDBs to handle a higher sampling rate.  in allocate_buffers()
447 	/* If there is already a sampling buffer allocated, it is very likely  in allocate_buffers()
448 	 * that the sampling facility is enabled too.  If the event to be  in allocate_buffers()
449 	 * initialized requires a greater sampling buffer, the allocation must  in allocate_buffers()
450 	 * be postponed.  Changing the sampling buffer requires the sampling  in allocate_buffers()
471 	/* Use a percentage-based approach to extend the sampling facility  in compute_sfb_extent()
518 /* extend_sampling_buffer() - Extend sampling buffer
519  * @sfb:	Sampling buffer structure (for local CPU)
522  * Use this function to extend the sampling buffer based on the overflow counter
525  * Important: This function disables the sampling facility in order to safely
526  *	      change the sampling buffer structure.  Do not call this function
538 	/* Disable the sampling facility to reset any states and also  in extend_sampling_buffer()
543 	/* Extend the sampling buffer.  in extend_sampling_buffer()
655 	 * Obtain the PID from the basic-sampling data entry and  in cpumsf_output_event_pid()
687 		/* The min/max sampling rates specifies the valid range  in getrate()
695 		 * sampling rate does not exceed this value.  This also helps  in getrate()
707 /* The sampling information (si) contains information about the
708  * min/max sampling intervals and the CPU speed.  So calculate the
709  * correct sampling interval and avoid the whole period adjust
712  * Since the CPU Measurement sampling facility can not handle frequency
713  * calculate the sampling interval when frequency is specified using
718  * set to the correct sampling rate.
756 	/* Reserve CPU-measurement sampling facility */  in __hw_perf_event_init()
765 	/* Access per-CPU sampling information (query sampling info) */  in __hw_perf_event_init()
769 	 * sampling info from the current CPU, otherwise use event->cpu to  in __hw_perf_event_init()
771 	 * Later, cpuhw indicates whether to allocate sampling buffers for a  in __hw_perf_event_init()
780 		 * sampling structure for accessing the CPU-specific QSI.  in __hw_perf_event_init()
786 	/* Check sampling facility authorization and, if not authorized,  in __hw_perf_event_init()
796 		pr_warn("CPU Measurement Facility sampling is temporarily not available\n");  in __hw_perf_event_init()
801 	/* Always enable basic sampling */  in __hw_perf_event_init()
804 	/* Check if diagnostic sampling is requested.  Deny if the required  in __hw_perf_event_init()
805 	 * sampling authorization is missing.  in __hw_perf_event_init()
823 	/* Allocate the per-CPU sampling buffer using the CPU information  in __hw_perf_event_init()
825 	 * CPU (event->cpu == -1; or cpuhw == NULL), allocate sampling  in __hw_perf_event_init()
832 		/* Event is not pinned, allocate sampling buffer on  in __hw_perf_event_init()
843 	/* If PID/TID sampling is active, replace the default overflow  in __hw_perf_event_init()
844 	 * handler to extract and resolve the PIDs from the basic-sampling  in __hw_perf_event_init()
866 	/* No support for taken branch sampling */  in cpumsf_pmu_event_init()
878 		/* Support sampling of CPU cycles in addition to the  in cpumsf_pmu_event_init()
881 		 * sampling events only.  in cpumsf_pmu_event_init()
919 	/* Check whether to extent the sampling buffer.  in cpumsf_pmu_enable()
921 	 * Two conditions trigger an increase of the sampling buffer for a  in cpumsf_pmu_enable()
924 	 *    2. Sampling overflows that contribute to pending allocations.  in cpumsf_pmu_enable()
926 	 * Note that the extend_sampling_buffer() function disables the sampling  in cpumsf_pmu_enable()
927 	 * facility, but it can be fully re-enabled using sampling controls that  in cpumsf_pmu_enable()
944 	/* (Re)enable the PMU and sampling facility */  in cpumsf_pmu_enable()
951 		pr_err("Loading sampling controls failed: op 1 err %i\n", err);  in cpumsf_pmu_enable()
972 	/* Switch off sampling activation control */  in cpumsf_pmu_disable()
979 		pr_err("Loading sampling controls failed: op 2 err %i\n", err);  in cpumsf_pmu_disable()
985 	 * TEAR/DEAR values are valid only if the sampling facility is  in cpumsf_pmu_disable()
987 	 * for a disabled sampling facility because cpumsf_pmu_enable()  in cpumsf_pmu_disable()
1112  * Walks through a sample-data-block and collects sampling data entries that are
1113  * then pushed to the perf event subsystem.  Depending on the sampling function,
1114  * there can be either basic-sampling or combined-sampling data entries.  A
1115  * combined-sampling data entry consists of a basic- and a diagnostic-sampling
1116  * data entry.	The sampling function is determined by the flags in the perf
1117  * event hardware structure.  The function always works with a combined-sampling
1120  * Note that the implementation focuses on basic-sampling data entries and, if
1121  * such an entry is not valid, the entire combined-sampling data entry is
1163 			 * from a combined basic- and diagnostic-sampling.  in hw_collect_samples()
1164 			 * If only basic-sampling is then active, entries are  in hw_collect_samples()
1180 /* hw_perf_event_update() - Process sampling buffer
1184  * Processes the sampling buffer and create perf event samples.
1185  * The sampling buffer position are retrieved and saved in the TEAR_REG
1201 	 * AUX buffer is used when in diagnostic sampling mode.  in hw_perf_event_update()
1224 			 * is reached, extend the sampling buffer.  in hw_perf_event_update()
1314  * Finish sampling on the cpu. Called by cpumsf_pmu_del() with pmu
1347  * Start sampling on the CPU. Called by cpumsf_pmu_add() when an event
1513  * Measurement alert handler for diagnostic mode sampling.
1540 			       "diagnostic-sampling mode is full\n",  in hw_collect_aux()
1604  * aux_buffer_setup() - Setup AUX buffer for diagnostic mode sampling
1630 		       "maximum sampling buffer limit\n",  in aux_buffer_setup()
1635 		       "minimum sampling buffer limit\n",  in aux_buffer_setup()
1717 /* Check if the new sampling period/frequency is appropriate.
1732 		 * sampling structure for accessing the CPU-specific QSI.  in cpumsf_pmu_check_period()
1750 /* Activate sampling control.
1751  * Next call of pmu_enable() starts sampling.
1767 /* Deactivate sampling control.
1768  * Next call of pmu_enable() stops sampling.
1805 	/* Set up sampling controls.  Always program the sampling register  in cpumsf_pmu_add()
1807 	 * that is used by hw_perf_event_update() to store the sampling buffer  in cpumsf_pmu_add()
1819 	/* Ensure sampling functions are in the disabled state.  If disabled,  in cpumsf_pmu_add()
1820 	 * switch on sampling enable control. */  in cpumsf_pmu_add()
1873  * The availablitiy depends on the CPU_MF sampling facility authorization
1875  * time by the sampling facility device driver.
1877  * also turned off for diagnostic sampling.
1880  * level for diagnostic sampling and installs the attribute
1881  * file for diagnostic sampling if necessary.
1974 	/* Sampling authorization change request */  in cpumf_measurement_alert()
1985 	/* Invalid sampling buffer entry */  in cpumf_measurement_alert()
1987 		pr_err("A sampling buffer entry is incorrect (alert=0x%x)\n",  in cpumf_measurement_alert()
2049 	pr_info("The sampling buffer limits have changed to: "  in param_set_sfb_size()
2062 	RS_INIT_FAILURE_BSDES	= 2,	/* Bad basic sampling size */
2069 	pr_err("Sampling facility support for perf is not available: "  in pr_cpumsf_err()
2093 		/* Sampling of diagnostic data authorized,  in init_cpum_sampling_pmu()