drm/amdkfd: add send exception operation

Add a debug operation that allows the debugger to send an exception
directly to runtime through a payload address.

For memory violations, normal vmfault signals will be applied to
notify runtime instead after passing in the saved exception data
when a memory violation was raised to the debugger.

For runtime exceptions, this will unblock the runtime enable
function which will be explained and implemented in a follow up
patch.
Signed-off-by: Jonathan Kim <jonathan.kim@amd.com>
Reviewed-by: Felix Kuehling <felix.kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdkfd/cik_event_interrupt.c

@@ -118,9 +118,9 @@ static void cik_event_interrupt_wq(struct kfd_node *dev,
 			return;
 
 		if (info.vmid == vmid)
-			kfd_signal_vm_fault_event(dev, pasid, &info);
+			kfd_signal_vm_fault_event(dev, pasid, &info, NULL);
 		else
-			kfd_signal_vm_fault_event(dev, pasid, NULL);
+			kfd_signal_vm_fault_event(dev, pasid, NULL, NULL);
 	}
 }
 

drivers/gpu/drm/amd/amdkfd/kfd_chardev.c

@@ -2833,6 +2833,11 @@ static int kfd_ioctl_set_debug_trap(struct file *filep, struct kfd_process *p, v
 		r = kfd_dbg_trap_disable(target);
 		break;
 	case KFD_IOC_DBG_TRAP_SEND_RUNTIME_EVENT:
+		r = kfd_dbg_send_exception_to_runtime(target,
+				args->send_runtime_event.gpu_id,
+				args->send_runtime_event.queue_id,
+				args->send_runtime_event.exception_mask);
+		break;
 	case KFD_IOC_DBG_TRAP_SET_EXCEPTIONS_ENABLED:
 	case KFD_IOC_DBG_TRAP_SET_WAVE_LAUNCH_OVERRIDE:
 	case KFD_IOC_DBG_TRAP_SET_WAVE_LAUNCH_MODE:

drivers/gpu/drm/amd/amdkfd/kfd_debug.c

@@ -125,6 +125,49 @@ bool kfd_dbg_ev_raise(uint64_t event_mask,
 	return is_subscribed;
 }
 
+int kfd_dbg_send_exception_to_runtime(struct kfd_process *p,
+					unsigned int dev_id,
+					unsigned int queue_id,
+					uint64_t error_reason)
+{
+	if (error_reason & KFD_EC_MASK(EC_DEVICE_MEMORY_VIOLATION)) {
+		struct kfd_process_device *pdd = NULL;
+		struct kfd_hsa_memory_exception_data *data;
+		int i;
+
+		for (i = 0; i < p->n_pdds; i++) {
+			if (p->pdds[i]->dev->id == dev_id) {
+				pdd = p->pdds[i];
+				break;
+			}
+		}
+
+		if (!pdd)
+			return -ENODEV;
+
+		data = (struct kfd_hsa_memory_exception_data *)
+						pdd->vm_fault_exc_data;
+
+		kfd_dqm_evict_pasid(pdd->dev->dqm, p->pasid);
+		kfd_signal_vm_fault_event(pdd->dev, p->pasid, NULL, data);
+		error_reason &= ~KFD_EC_MASK(EC_DEVICE_MEMORY_VIOLATION);
+	}
+
+	if (error_reason & (KFD_EC_MASK(EC_PROCESS_RUNTIME))) {
+		/*
+		 * block should only happen after the debugger receives runtime
+		 * enable notice.
+		 */
+		up(&p->runtime_enable_sema);
+		error_reason &= ~KFD_EC_MASK(EC_PROCESS_RUNTIME);
+	}
+
+	if (error_reason)
+		return kfd_send_exception_to_runtime(p, queue_id, error_reason);
+
+	return 0;
+}
+
 static int kfd_dbg_set_queue_workaround(struct queue *q, bool enable)
 {
 	struct mqd_update_info minfo = {0};

drivers/gpu/drm/amd/amdkfd/kfd_debug.h

@@ -34,6 +34,12 @@ int kfd_dbg_trap_disable(struct kfd_process *target);
 int kfd_dbg_trap_enable(struct kfd_process *target, uint32_t fd,
 			void __user *runtime_info,
 			uint32_t *runtime_info_size);
+
+int kfd_dbg_send_exception_to_runtime(struct kfd_process *p,
+					unsigned int dev_id,
+					unsigned int queue_id,
+					uint64_t error_reason);
+
 static inline bool kfd_dbg_is_per_vmid_supported(struct kfd_node *dev)
 {
 	return KFD_GC_VERSION(dev) == IP_VERSION(9, 4, 2) ||

drivers/gpu/drm/amd/amdkfd/kfd_events.c

@@ -1222,7 +1222,8 @@ void kfd_signal_hw_exception_event(u32 pasid)
 }
 
 void kfd_signal_vm_fault_event(struct kfd_node *dev, u32 pasid,
-			       struct kfd_vm_fault_info *info)
+				struct kfd_vm_fault_info *info,
+				struct kfd_hsa_memory_exception_data *data)
 {
 	struct kfd_event *ev;
 	uint32_t id;

drivers/gpu/drm/amd/amdkfd/kfd_int_process_v9.c

@@ -362,7 +362,7 @@ static void event_interrupt_wq_v9(struct kfd_node *dev,
 
 		kfd_smi_event_update_vmfault(dev, pasid);
 		kfd_dqm_evict_pasid(dev->dqm, pasid);
-		kfd_signal_vm_fault_event(dev, pasid, &info);
+		kfd_signal_vm_fault_event(dev, pasid, &info, NULL);
 	}
 }
 

drivers/gpu/drm/amd/amdkfd/kfd_priv.h

@@ -979,6 +979,7 @@ struct kfd_process {
 	bool queues_paused;
 
 	/* Tracks runtime enable status */
+	struct semaphore runtime_enable_sema;
 	struct kfd_runtime_info runtime_info;
 
 };
@@ -1447,7 +1448,8 @@ int kfd_get_num_events(struct kfd_process *p);
 int kfd_event_destroy(struct kfd_process *p, uint32_t event_id);
 
 void kfd_signal_vm_fault_event(struct kfd_node *dev, u32 pasid,
-				struct kfd_vm_fault_info *info);
+				struct kfd_vm_fault_info *info,
+				struct kfd_hsa_memory_exception_data *data);
 
 void kfd_signal_reset_event(struct kfd_node *dev);
 
@@ -1463,6 +1465,9 @@ static inline bool kfd_flush_tlb_after_unmap(struct kfd_dev *dev)
 	       KFD_GC_VERSION(dev) == IP_VERSION(9, 4, 0);
 }
 
+int kfd_send_exception_to_runtime(struct kfd_process *p,
+				unsigned int queue_id,
+				uint64_t error_reason);
 bool kfd_is_locked(void);
 
 /* Compute profile */

drivers/gpu/drm/amd/amdkfd/kfd_process.c

@@ -1462,6 +1462,7 @@ static struct kfd_process *create_process(const struct task_struct *thread)
 	process->debugger_process = NULL;
 	process->exception_enable_mask = 0;
 	atomic_set(&process->debugged_process_count, 0);
+	sema_init(&process->runtime_enable_sema, 0);
 
 	process->pasid = kfd_pasid_alloc();
 	if (process->pasid == 0) {
@@ -2120,6 +2121,75 @@ void kfd_flush_tlb(struct kfd_process_device *pdd, enum TLB_FLUSH_TYPE type)
 	}
 }
 
+struct send_exception_work_handler_workarea {
+	struct work_struct work;
+	struct kfd_process *p;
+	unsigned int queue_id;
+	uint64_t error_reason;
+};
+
+static void send_exception_work_handler(struct work_struct *work)
+{
+	struct send_exception_work_handler_workarea *workarea;
+	struct kfd_process *p;
+	struct queue *q;
+	struct mm_struct *mm;
+	struct kfd_context_save_area_header __user *csa_header;
+	uint64_t __user *err_payload_ptr;
+	uint64_t cur_err;
+	uint32_t ev_id;
+
+	workarea = container_of(work,
+				struct send_exception_work_handler_workarea,
+				work);
+	p = workarea->p;
+
+	mm = get_task_mm(p->lead_thread);
+
+	if (!mm)
+		return;
+
+	kthread_use_mm(mm);
+
+	q = pqm_get_user_queue(&p->pqm, workarea->queue_id);
+
+	if (!q)
+		goto out;
+
+	csa_header = (void __user *)q->properties.ctx_save_restore_area_address;
+
+	get_user(err_payload_ptr, (uint64_t __user **)&csa_header->err_payload_addr);
+	get_user(cur_err, err_payload_ptr);
+	cur_err |= workarea->error_reason;
+	put_user(cur_err, err_payload_ptr);
+	get_user(ev_id, &csa_header->err_event_id);
+
+	kfd_set_event(p, ev_id);
+
+out:
+	kthread_unuse_mm(mm);
+	mmput(mm);
+}
+
+int kfd_send_exception_to_runtime(struct kfd_process *p,
+			unsigned int queue_id,
+			uint64_t error_reason)
+{
+	struct send_exception_work_handler_workarea worker;
+
+	INIT_WORK_ONSTACK(&worker.work, send_exception_work_handler);
+
+	worker.p = p;
+	worker.queue_id = queue_id;
+	worker.error_reason = error_reason;
+
+	schedule_work(&worker.work);
+	flush_work(&worker.work);
+	destroy_work_on_stack(&worker.work);
+
+	return 0;
+}
+
 struct kfd_process_device *kfd_process_device_data_by_id(struct kfd_process *p, uint32_t gpu_id)
 {
 	int i;
@@ -2179,4 +2249,3 @@ int kfd_debugfs_mqds_by_process(struct seq_file *m, void *data)
 }
 
 #endif
-