From 979f867191f80e74713394cf8c0a3c1b3662b648 Mon Sep 17 00:00:00 2001
From: Michael Cree <mcree@orcon.net.nz>
Date: Mon, 9 Aug 2010 17:20:08 -0700
Subject: alpha: implement HW performance events on the EV67 and later CPUs

This implements hardware performance events for the EV67 and later CPUs
within the Linux performance events subsystem.  Only using the performance
monitoring unit in HP/Compaq's so called "Aggregrate mode" is supported.

The code has been implemented in a manner that makes extension to other
older Alpha CPUs relatively straightforward should some mug wish to
indulge themselves.

Signed-off-by: Michael Cree <mcree@orcon.net.nz>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jay Estabrook <jay.estabrook@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 arch/alpha/kernel/time.c | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

(limited to 'arch/alpha/kernel/time.c')

diff --git a/arch/alpha/kernel/time.c b/arch/alpha/kernel/time.c
index 1efbed8..eacceb2 100644
--- a/arch/alpha/kernel/time.c
+++ b/arch/alpha/kernel/time.c
@@ -41,6 +41,7 @@
 #include <linux/init.h>
 #include <linux/bcd.h>
 #include <linux/profile.h>
+#include <linux/perf_event.h>
 
 #include <asm/uaccess.h>
 #include <asm/io.h>
@@ -82,6 +83,26 @@ static struct {
 
 unsigned long est_cycle_freq;
 
+#ifdef CONFIG_PERF_EVENTS
+
+DEFINE_PER_CPU(u8, perf_event_pending);
+
+#define set_perf_event_pending_flag()  __get_cpu_var(perf_event_pending) = 1
+#define test_perf_event_pending()      __get_cpu_var(perf_event_pending)
+#define clear_perf_event_pending()     __get_cpu_var(perf_event_pending) = 0
+
+void set_perf_event_pending(void)
+{
+	set_perf_event_pending_flag();
+}
+
+#else  /* CONFIG_PERF_EVENTS */
+
+#define test_perf_event_pending()      0
+#define clear_perf_event_pending()
+
+#endif /* CONFIG_PERF_EVENTS */
+
 
 static inline __u32 rpcc(void)
 {
@@ -175,6 +196,11 @@ irqreturn_t timer_interrupt(int irq, void *dev)
 		update_process_times(user_mode(get_irq_regs()));
 #endif
 
+	if (test_perf_event_pending()) {
+		clear_perf_event_pending();
+		perf_event_do_pending();
+	}
+
 	return IRQ_HANDLED;
 }
 
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