ocxl: Add new kernel traces

Add specific kernel traces which provide information on mmu notifier and on
pages range.

Signed-off-by: Christophe Lombard <clombard@linux.vnet.ibm.com>
Acked-by: Frederic Barrat <fbarrat@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201125155013.39955-6-clombard@linux.vnet.ibm.com

drivers/misc/ocxl/link.c

@@ -499,6 +499,7 @@ static void invalidate_range(struct mmu_notifier *mn,
 	unsigned long addr, pid, page_size = PAGE_SIZE;
 
 	pid = mm->context.id;
+	trace_ocxl_mmu_notifier_range(start, end, pid);
 
 	spin_lock(&link->atsd_lock);
 	for (addr = start; addr < end; addr += page_size)
@@ -590,6 +591,7 @@ int ocxl_link_add_pe(void *link_handle, int pasid, u32 pidr, u32 tidr,
 			/* Use MMIO registers for the TLB Invalidate
 			 * operations.
 			 */
+			trace_ocxl_init_mmu_notifier(pasid, mm->context.id);
 			mmu_notifier_register(&pe_data->mmu_notifier, mm);
 		}
 	}
@@ -725,6 +727,8 @@ int ocxl_link_remove_pe(void *link_handle, int pasid)
 	} else {
 		if (pe_data->mm) {
 			if (link->arva) {
+				trace_ocxl_release_mmu_notifier(pasid,
+								pe_data->mm->context.id);
 				mmu_notifier_unregister(&pe_data->mmu_notifier,
 							pe_data->mm);
 				spin_lock(&link->atsd_lock);

drivers/misc/ocxl/trace.h

@@ -8,6 +8,70 @@
 
 #include <linux/tracepoint.h>
 
+
+TRACE_EVENT(ocxl_mmu_notifier_range,
+	TP_PROTO(unsigned long start, unsigned long end, unsigned long pidr),
+	TP_ARGS(start, end, pidr),
+
+	TP_STRUCT__entry(
+		__field(unsigned long, start)
+		__field(unsigned long, end)
+		__field(unsigned long, pidr)
+	),
+
+	TP_fast_assign(
+		__entry->start = start;
+		__entry->end = end;
+		__entry->pidr = pidr;
+	),
+
+	TP_printk("start=0x%lx end=0x%lx pidr=0x%lx",
+		__entry->start,
+		__entry->end,
+		__entry->pidr
+	)
+);
+
+TRACE_EVENT(ocxl_init_mmu_notifier,
+	TP_PROTO(int pasid, unsigned long pidr),
+	TP_ARGS(pasid, pidr),
+
+	TP_STRUCT__entry(
+		__field(int, pasid)
+		__field(unsigned long, pidr)
+	),
+
+	TP_fast_assign(
+		__entry->pasid = pasid;
+		__entry->pidr = pidr;
+	),
+
+	TP_printk("pasid=%d, pidr=0x%lx",
+		__entry->pasid,
+		__entry->pidr
+	)
+);
+
+TRACE_EVENT(ocxl_release_mmu_notifier,
+	TP_PROTO(int pasid, unsigned long pidr),
+	TP_ARGS(pasid, pidr),
+
+	TP_STRUCT__entry(
+		__field(int, pasid)
+		__field(unsigned long, pidr)
+	),
+
+	TP_fast_assign(
+		__entry->pasid = pasid;
+		__entry->pidr = pidr;
+	),
+
+	TP_printk("pasid=%d, pidr=0x%lx",
+		__entry->pasid,
+		__entry->pidr
+	)
+);
+
 DECLARE_EVENT_CLASS(ocxl_context,
 	TP_PROTO(pid_t pid, void *spa, int pasid, u32 pidr, u32 tidr),
 	TP_ARGS(pid, spa, pasid, pidr, tidr),