[PATCH 2/3] MIPS: adding support for software perf events

[Deng-Cheng Zhu <dengcheng.zhu@gmail.com>]

This is the minimal support for the SW perf events, required as a part of
the measurable stuff by the Linux performance counter subsystem.

Signed-off-by: Deng-Cheng Zhu <dengcheng.zhu@gmail.com>
---
 arch/mips/Kconfig                  |    2 ++
 arch/mips/include/asm/perf_event.h |   28 ++++++++++++++++++++++++++++
 arch/mips/mm/fault.c               |   11 +++++++++--
 3 files changed, 39 insertions(+), 2 deletions(-)
 create mode 100644 arch/mips/include/asm/perf_event.h

diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index 7161751..cf33418 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -4,6 +4,8 @@ config MIPS
 	select HAVE_GENERIC_DMA_COHERENT
 	select HAVE_IDE
 	select HAVE_OPROFILE
+	select HAVE_PERF_EVENTS
+	select PERF_USE_VMALLOC
 	select GENERIC_ATOMIC64
 	select HAVE_ARCH_KGDB
 	select HAVE_FUNCTION_TRACER
diff --git a/arch/mips/include/asm/perf_event.h b/arch/mips/include/asm/perf_event.h
new file mode 100644
index 0000000..bcf54bc
--- /dev/null
+++ b/arch/mips/include/asm/perf_event.h
@@ -0,0 +1,28 @@
+/*
+ * linux/arch/mips/include/asm/perf_event.h
+ *
+ * Copyright (C) 2010 MIPS Technologies, Inc. Deng-Cheng Zhu
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+
+#ifndef __MIPS_PERF_EVENT_H__
+#define __MIPS_PERF_EVENT_H__
+
+extern int (*perf_irq)(void);
+
+/*
+ * MIPS performance counters do not raise NMI upon overflow, a regular
+ * interrupt will be signaled. Hence we can do the pending perf event
+ * work at the tail of the irq handler.
+ */
+static inline void
+set_perf_event_pending(void)
+{
+}
+
+#endif /* __MIPS_PERF_EVENT_H__ */
+
diff --git a/arch/mips/mm/fault.c b/arch/mips/mm/fault.c
index b78f7d9..5987d2b 100644
--- a/arch/mips/mm/fault.c
+++ b/arch/mips/mm/fault.c
@@ -18,6 +18,7 @@
 #include <linux/smp.h>
 #include <linux/vt_kern.h>		/* For unblank_screen() */
 #include <linux/module.h>
+#include <linux/perf_event.h>
 
 #include <asm/branch.h>
 #include <asm/mmu_context.h>
@@ -132,6 +133,7 @@ good_area:
 	 * the fault.
 	 */
 	fault = handle_mm_fault(mm, vma, address, write ? FAULT_FLAG_WRITE : 0);
+	perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, 0, regs, address);
 	if (unlikely(fault & VM_FAULT_ERROR)) {
 		if (fault & VM_FAULT_OOM)
 			goto out_of_memory;
@@ -139,10 +141,15 @@ good_area:
 			goto do_sigbus;
 		BUG();
 	}
-	if (fault & VM_FAULT_MAJOR)
+	if (fault & VM_FAULT_MAJOR) {
+		perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ,
+				1, 0, regs, address);
 		tsk->maj_flt++;
-	else
+	} else {
+		perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN,
+				1, 0, regs, address);
 		tsk->min_flt++;
+	}
 
 	up_read(&mm->mmap_sem);
 	return;
-- 
1.7.0.4