1 // SPDX-License-Identifier: GPL-2.0-only
4  *  Simple profiling. Manages a direct-mapped profile hit count buffer,
9  *  Scheduler profiling support, Arjan van de Ven and Ingo Molnar,
13  *  Amortized hit count accounting via per-cpu open-addressed hashtables
71 			prof_shift = clamp(par, 0, BITS_PER_LONG - 1);  in profile_setup()
82 			prof_shift = clamp(par, 0, BITS_PER_LONG - 1);  in profile_setup()
90 			prof_shift = clamp(par, 0, BITS_PER_LONG - 1);  in profile_setup()
94 		prof_shift = clamp(par, 0, BITS_PER_LONG - 1);  in profile_setup()
111 	prof_len = (_etext - _stext) >> prof_shift;  in profile_init()
116 		return -EINVAL;  in profile_init()
122 		return -ENOMEM;  in profile_init()
140 	return -ENOMEM;  in profile_init()
180 	int err = -EINVAL;  in profile_event_register()
199 	int err = -EINVAL;  in profile_event_unregister()
218  * Each cpu has a pair of open-addressed hashtables for pending
221  * Flip requests are serialized by the profile_flip_mutex. The sole
227  * The open-addressed hashtables are indexed by profile buffer slot
242  * and was vaguely inspired by ppc64 firmware-supported inverted
246  * -- nyc
299 	pc = min((pc - (unsigned long)_stext) >> prof_shift, prof_len - 1);  in do_profile_hits()
300 	i = primary = (pc & (NR_PROFILE_GRP - 1)) << PROFILE_GRPSHIFT;  in do_profile_hits()
301 	secondary = (~(pc << 1) & (NR_PROFILE_GRP - 1)) << PROFILE_GRPSHIFT;  in do_profile_hits()
309 	 * We buffer the global profiler buffer into a per-CPU  in do_profile_hits()
311 	 * NUMA-alien) accesses. The write-queue is self-coalescing:  in do_profile_hits()
325 		i = (i + secondary) & (NR_PROFILE_HIT - 1);  in do_profile_hits()
329 	 * Add the current hit(s) and flush the write-queue out  in do_profile_hits()
374 			return -ENOMEM;  in profile_prepare_cpu()
397 	pc = ((unsigned long)__pc - (unsigned long)_stext) >> prof_shift;  in do_profile_hits()
398 	atomic_add(nr_hits, &prof_buffer[min(pc, prof_len - 1)]);  in do_profile_hits()
442 		return -ENOMEM;  in prof_cpu_mask_proc_write()
484 	if (count > (prof_len+1)*sizeof(unsigned int) - p)  in read_profile()
485 		count = (prof_len+1)*sizeof(unsigned int) - p;  in read_profile()
490 			return -EFAULT;  in read_profile()
491 		buf++; p++; count--; read++;  in read_profile()
493 	pnt = (char *)prof_buffer + p - sizeof(atomic_t);  in read_profile()
495 		return -EFAULT;  in read_profile()
504  * Writing a 'profiling multiplier' value into it also re-sets the profiling
517 			return -EFAULT;  in write_profile()
520 			return -EINVAL;  in write_profile()