drm/amdkfd: add debug set flags operation

Allow the debugger to set single memory and single ALU operations.

Some exceptions are imprecise (memory violations, address watch) in the
sense that a trap occurs only when the exception interrupt occurs and
not at the non-halting faulty instruction.  Trap temporaries 0 & 1 save
the program counter address, which means that these values will not point
to the faulty instruction address but to whenever the interrupt was
raised.

Setting the Single Memory Operations flag will inject an automatic wait
on every memory operation instruction forcing imprecise memory exceptions
to become precise at the cost of performance.  This setting is not
permitted on debug devices that support only a global setting of this
option.

Return the previous set flags to the debugger as well.
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/kfd_chardev.c

@@ -3035,6 +3035,8 @@ static int kfd_ioctl_set_debug_trap(struct file *filep, struct kfd_process *p, v
 				args->clear_node_address_watch.id);
 		break;
 	case KFD_IOC_DBG_TRAP_SET_FLAGS:
+		r = kfd_dbg_trap_set_flags(target, &args->set_flags.flags);
+		break;
 	case KFD_IOC_DBG_TRAP_QUERY_DEBUG_EVENT:
 	case KFD_IOC_DBG_TRAP_QUERY_EXCEPTION_INFO:
 	case KFD_IOC_DBG_TRAP_GET_QUEUE_SNAPSHOT:

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

@@ -23,6 +23,7 @@
 #include "kfd_debug.h"
 #include "kfd_device_queue_manager.h"
 #include <linux/file.h>
+#include <uapi/linux/kfd_ioctl.h>
 
 #define MAX_WATCH_ADDRESSES	4
 
@@ -423,6 +424,59 @@ static void kfd_dbg_clear_process_address_watch(struct kfd_process *target)
 			kfd_dbg_trap_clear_dev_address_watch(target->pdds[i], j);
 }
 
+int kfd_dbg_trap_set_flags(struct kfd_process *target, uint32_t *flags)
+{
+	uint32_t prev_flags = target->dbg_flags;
+	int i, r = 0, rewind_count = 0;
+
+	for (i = 0; i < target->n_pdds; i++) {
+		if (!kfd_dbg_is_per_vmid_supported(target->pdds[i]->dev) &&
+			(*flags & KFD_DBG_TRAP_FLAG_SINGLE_MEM_OP)) {
+			*flags = prev_flags;
+			return -EACCES;
+		}
+	}
+
+	target->dbg_flags = *flags & KFD_DBG_TRAP_FLAG_SINGLE_MEM_OP;
+	*flags = prev_flags;
+	for (i = 0; i < target->n_pdds; i++) {
+		struct kfd_process_device *pdd = target->pdds[i];
+
+		if (!kfd_dbg_is_per_vmid_supported(pdd->dev))
+			continue;
+
+		if (!pdd->dev->kfd->shared_resources.enable_mes)
+			r = debug_refresh_runlist(pdd->dev->dqm);
+		else
+			r = kfd_dbg_set_mes_debug_mode(pdd);
+
+		if (r) {
+			target->dbg_flags = prev_flags;
+			break;
+		}
+
+		rewind_count++;
+	}
+
+	/* Rewind flags */
+	if (r) {
+		target->dbg_flags = prev_flags;
+
+		for (i = 0; i < rewind_count; i++) {
+			struct kfd_process_device *pdd = target->pdds[i];
+
+			if (!kfd_dbg_is_per_vmid_supported(pdd->dev))
+				continue;
+
+			if (!pdd->dev->kfd->shared_resources.enable_mes)
+				debug_refresh_runlist(pdd->dev->dqm);
+			else
+				kfd_dbg_set_mes_debug_mode(pdd);
+		}
+	}
+
+	return r;
+}
 
 /* kfd_dbg_trap_deactivate:
  *	target: target process
@@ -437,9 +491,13 @@ void kfd_dbg_trap_deactivate(struct kfd_process *target, bool unwind, int unwind
 	int i;
 
 	if (!unwind) {
+		uint32_t flags = 0;
+
 		cancel_work_sync(&target->debug_event_workarea);
 		kfd_dbg_clear_process_address_watch(target);
 		kfd_dbg_trap_set_wave_launch_mode(target, 0);
+
+		kfd_dbg_trap_set_flags(target, &flags);
 	}
 
 	for (i = 0; i < target->n_pdds; i++) {

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

@@ -57,6 +57,7 @@ int kfd_dbg_trap_set_dev_address_watch(struct kfd_process_device *pdd,
 					uint32_t watch_address_mask,
 					uint32_t *watch_id,
 					uint32_t watch_mode);
+int kfd_dbg_trap_set_flags(struct kfd_process *target, uint32_t *flags);
 int kfd_dbg_send_exception_to_runtime(struct kfd_process *p,
 					unsigned int dev_id,
 					unsigned int queue_id,