1 // SPDX-License-Identifier: GPL-2.0+
15  * HW_breakpoint: a unified kernel/user-space hardware breakpoint facility,
17  * This file contains the arch-independent routines.
45 	/* Number of non-pinned cpu/task breakpoints in a cpu */
62 /* Gather the number of total pinned and un-pinned bp in a cpuset */
90 	unsigned int *tsk_pinned = get_bp_info(cpu, type)->tsk_pinned;  in max_task_bp_pinned()
93 	for (i = nr_slots[type] - 1; i >= 0; i--) {  in max_task_bp_pinned()
107 	struct task_struct *tsk = bp->hw.target;  in task_bp_pinned()
112 		if (iter->hw.target == tsk &&  in task_bp_pinned()
113 		    find_slot_idx(iter->attr.bp_type) == type &&  in task_bp_pinned()
114 		    (iter->cpu < 0 || cpu == iter->cpu))  in task_bp_pinned()
123 	if (bp->cpu >= 0)  in cpumask_of_bp()
124 		return cpumask_of(bp->cpu);  in cpumask_of_bp()
129  * Report the number of pinned/un-pinned breakpoints we have in
130  * a given cpu (cpu > -1) or in all of them (cpu = -1).
143 		nr = info->cpu_pinned;  in fetch_bp_busy_slots()
144 		if (!bp->hw.target)  in fetch_bp_busy_slots()
149 		if (nr > slots->pinned)  in fetch_bp_busy_slots()
150 			slots->pinned = nr;  in fetch_bp_busy_slots()
152 		nr = info->flexible;  in fetch_bp_busy_slots()
153 		if (nr > slots->flexible)  in fetch_bp_busy_slots()
154 			slots->flexible = nr;  in fetch_bp_busy_slots()
166 	slots->pinned += weight;  in fetch_this_slot()
175 	unsigned int *tsk_pinned = get_bp_info(cpu, type)->tsk_pinned;  in toggle_bp_task_slot()
178 	old_idx = task_bp_pinned(cpu, bp, type) - 1;  in toggle_bp_task_slot()
182 		tsk_pinned[old_idx]--;  in toggle_bp_task_slot()
198 		weight = -weight;  in toggle_bp_slot()
201 	if (!bp->hw.target) {  in toggle_bp_slot()
202 		get_bp_info(bp->cpu, type)->cpu_pinned += weight;  in toggle_bp_slot()
211 		list_add_tail(&bp->hw.bp_list, &bp_task_head);  in toggle_bp_slot()
213 		list_del(&bp->hw.bp_list);  in toggle_bp_slot()
226  * Function to perform processor-specific cleanup during unregistration
239  *  == Non-pinned counter == (Considered as pinned for now)
241  *   - If attached to a single cpu, check:
243  *       (per_cpu(info->flexible, cpu) || (per_cpu(info->cpu_pinned, cpu)
244  *           + max(per_cpu(info->tsk_pinned, cpu)))) < HBP_NUM
246  *       -> If there are already non-pinned counters in this cpu, it means
252  *   - If attached to every cpus, check:
254  *       (per_cpu(info->flexible, *) || (max(per_cpu(info->cpu_pinned, *))
255  *           + max(per_cpu(info->tsk_pinned, *)))) < HBP_NUM
257  *       -> This is roughly the same, except we check the number of per cpu
264  *   - If attached to a single cpu, check:
266  *       ((per_cpu(info->flexible, cpu) > 1) + per_cpu(info->cpu_pinned, cpu)
267  *            + max(per_cpu(info->tsk_pinned, cpu))) < HBP_NUM
269  *       -> Same checks as before. But now the info->flexible, if any, must keep
272  *   - If attached to every cpus, check:
274  *       ((per_cpu(info->flexible, *) > 1) + max(per_cpu(info->cpu_pinned, *))
275  *            + max(per_cpu(info->tsk_pinned, *))) < HBP_NUM
286 		return -ENOMEM;  in __reserve_bp_slot()
291 		return -EINVAL;  in __reserve_bp_slot()
305 		return -ENOSPC;  in __reserve_bp_slot()
322 	ret = __reserve_bp_slot(bp, bp->attr.bp_type);  in reserve_bp_slot()
346 	__release_bp_slot(bp, bp->attr.bp_type);  in release_bp_slot()
391 		return -1;  in dbg_reserve_bp_slot()
393 	return __reserve_bp_slot(bp, bp->attr.bp_type);  in dbg_reserve_bp_slot()
399 		return -1;  in dbg_release_bp_slot()
401 	__release_bp_slot(bp, bp->attr.bp_type);  in dbg_release_bp_slot()
417 		if (attr->exclude_kernel)  in hw_breakpoint_parse()
418 			return -EINVAL;  in hw_breakpoint_parse()
424 			return -EPERM;  in hw_breakpoint_parse()
439 	err = hw_breakpoint_parse(bp, &bp->attr, &hw);  in register_perf_hw_breakpoint()
445 	bp->hw.info = hw;  in register_perf_hw_breakpoint()
451  * register_user_hw_breakpoint - register a hardware breakpoint for user space
453  * @triggered: callback to trigger when we hit the breakpoint
454  * @context: context data could be used in the triggered callback
459 			    perf_overflow_handler_t triggered,  in register_user_hw_breakpoint()  argument
463 	return perf_event_create_kernel_counter(attr, -1, tsk, triggered,  in register_user_hw_breakpoint()
471 	to->bp_addr = from->bp_addr;  in hw_breakpoint_copy_attr()
472 	to->bp_type = from->bp_type;  in hw_breakpoint_copy_attr()
473 	to->bp_len  = from->bp_len;  in hw_breakpoint_copy_attr()
474 	to->disabled = from->disabled;  in hw_breakpoint_copy_attr()
491 		old_attr = bp->attr;  in modify_user_hw_breakpoint_check()
494 			return -EINVAL;  in modify_user_hw_breakpoint_check()
497 	if (bp->attr.bp_type != attr->bp_type) {  in modify_user_hw_breakpoint_check()
498 		err = modify_bp_slot(bp, bp->attr.bp_type, attr->bp_type);  in modify_user_hw_breakpoint_check()
503 	hw_breakpoint_copy_attr(&bp->attr, attr);  in modify_user_hw_breakpoint_check()
504 	bp->hw.info = hw;  in modify_user_hw_breakpoint_check()
510  * modify_user_hw_breakpoint - modify a user-space hardware breakpoint
524 	if (irqs_disabled() && bp->ctx && bp->ctx->task == current)  in modify_user_hw_breakpoint()
531 	if (!bp->attr.disabled)  in modify_user_hw_breakpoint()
539  * unregister_hw_breakpoint - unregister a user-space hardware breakpoint
551  * register_wide_hw_breakpoint - register a wide breakpoint in the kernel
553  * @triggered: callback to trigger when we hit the breakpoint
554  * @context: context data could be used in the triggered callback
560 			    perf_overflow_handler_t triggered,  in register_wide_hw_breakpoint()  argument
569 		return (void __percpu __force *)ERR_PTR(-ENOMEM);  in register_wide_hw_breakpoint()
574 						      triggered, context);  in register_wide_hw_breakpoint()
593  * unregister_wide_hw_breakpoint - unregister a wide breakpoint in the kernel
622 	if (bp->attr.type != PERF_TYPE_BREAKPOINT)  in hw_breakpoint_event_init()
623 		return -ENOENT;  in hw_breakpoint_event_init()
629 		return -EOPNOTSUPP;  in hw_breakpoint_event_init()
635 	bp->destroy = bp_perf_event_destroy;  in hw_breakpoint_event_init()
643 		bp->hw.state = PERF_HES_STOPPED;  in hw_breakpoint_add()
646 		bp->hw.last_period = bp->hw.sample_period;  in hw_breakpoint_add()
660 	bp->hw.state = 0;  in hw_breakpoint_start()
665 	bp->hw.state = PERF_HES_STOPPED;  in hw_breakpoint_stop()
691 			info->tsk_pinned = kcalloc(nr_slots[i], sizeof(int),  in init_hw_breakpoint()
693 			if (!info->tsk_pinned)  in init_hw_breakpoint()
707 			kfree(get_bp_info(err_cpu, i)->tsk_pinned);  in init_hw_breakpoint()
712 	return -ENOMEM;  in init_hw_breakpoint()