xtensa: count software page fault perf events

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

arch/xtensa/mm/fault.c

@@ -15,6 +15,7 @@
 #include <linux/mm.h>
 #include <linux/module.h>
 #include <linux/hardirq.h>
+#include <linux/perf_event.h>
 #include <linux/uaccess.h>
 #include <asm/mmu_context.h>
 #include <asm/cacheflush.h>
@@ -142,6 +143,12 @@ void do_page_fault(struct pt_regs *regs)
 	}
 
 	up_read(&mm->mmap_sem);
+	perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
+	if (flags & VM_FAULT_MAJOR)
+		perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, regs, address);
+	else if (flags & VM_FAULT_MINOR)
+		perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, regs, address);
+
 	return;
 
 	/* Something tried to access memory that isn't in our memory map..