From fd96d80a4642a569bc01d4bfd7b11ab60591165b Mon Sep 17 00:00:00 2001
From: Sathya Narayanan <sramamir@eng.ucsd.edu>
Date: Mon, 1 Feb 2016 09:14:24 -0800
Subject: [PATCH] Adding driver files

---
 drivers/osproject.c         | 56 +++++++++++++++++++++++++++++++++++++++++++++
 drivers/osproject_syscall.c | 23 +++++++++++++++++++
 drivers/osproject_task.c    | 34 +++++++++++++++++++++++++++
 3 files changed, 113 insertions(+)
 create mode 100644 drivers/osproject.c
 create mode 100644 drivers/osproject_syscall.c
 create mode 100644 drivers/osproject_task.c

diff --git a/drivers/osproject.c b/drivers/osproject.c
new file mode 100644
index 0000000..a768a0d
--- /dev/null
+++ b/drivers/osproject.c
@@ -0,0 +1,56 @@
+/*   
+ *    *  hello.c ­ The simplest kernel module. 
+ *     */ 
+#include <linux/module.h>
+
+#define ARMV7_PMNC_E		(1 << 0) /* Enable all counters */
+#define ARMV7_PMNC_P		(1 << 1) /* Reset all counters */
+#define ARMV7_PMNC_C		(1 << 2) /* Cycle counter reset */
+#define ARMV7_PMNC_D		(1 << 3) /* CCNT counts every 64th cpu cycle */
+#define ARMV7_PMNC_X		(1 << 4) /* Export to ETM */
+#define ARMV7_PMNC_DP		(1 << 5) /* Disable CCNT if non-invasive debug*/
+#define	ARMV7_PMNC_N_SHIFT	11	 /* Number of counters supported */
+#define	ARMV7_PMNC_N_MASK	0x1f
+#define	ARMV7_PMNC_MASK		0x3f	 /* Mask for writable bits */
+
+/*101b9173
+static u32 armv7_pmnc_read(void)
+{
+	u32 val;
+	asm volatile("mrc p15, 0, %0, c9, c12, 0" : "=r"(val));
+	return val;
+}
+
+static void armv7_pmnc_write(u32 val)
+{
+	val &= ARMV7_PMNC_MASK;
+	isb();
+	asm volatile("mcr p15, 0, %0, c9, c12, 0" :: "r"(val));
+}
+*/
+
+int init_module() 
+{ 
+	unsigned int regr;
+	unsigned int i;
+	unsigned int a, b;
+
+	asm volatile("mrc p15, 0, %0, c9, c14, 0" : "=r" (regr));
+	pr_info("regr: %x\n", regr);
+
+	regr = 0;
+	for (i = 0; i < 1000; i++) {
+		asm volatile("mrc p15, 0, %0, c9, c13, 0" : "=r" (a));
+		asm volatile("mrc p15, 0, %0, c9, c13, 0" : "=r" (b));
+		regr += b - a;
+		pr_info("overhead: %u\n", b - a);
+	}
+	pr_info("Measurement overhead: %u\n", regr);
+
+
+	return 1; 
+}
+
+void cleanup_module()
+{
+}
diff --git a/drivers/osproject_syscall.c b/drivers/osproject_syscall.c
new file mode 100644
index 0000000..4893cba
--- /dev/null
+++ b/drivers/osproject_syscall.c
@@ -0,0 +1,23 @@
+#include <linux/module.h>
+#include <linux/sched.h>
+
+int init_module() 
+{ 
+	unsigned int regr;
+	unsigned int i;
+	unsigned int a, b;
+
+	asm volatile("mrc p15, 0, %0, c9, c14, 0" : "=r" (regr));
+	pr_info("User access regr: %x\n", regr);
+
+	asm volatile("mrc p15, 0, %0, c9, c13, 0" : "=r" (a));
+	i = current->pid;
+	asm volatile("mrc p15, 0, %0, c9, c13, 0" : "=r" (b));
+
+	pr_info("PID: %u, Time for getpid: %u\n", i, b - a);
+	return 0; 
+}
+
+void cleanup_module()
+{
+}
diff --git a/drivers/osproject_task.c b/drivers/osproject_task.c
new file mode 100644
index 0000000..112c9d2
--- /dev/null
+++ b/drivers/osproject_task.c
@@ -0,0 +1,34 @@
+#include <stdio.h>
+
+int main() 
+{ 
+	unsigned int regr;
+	unsigned int a, b;
+	unsigned int avg;
+	unsigned int pid;
+
+	asm volatile("mrc p15, 0, %0, c9, c14, 0" : "=r" (regr));
+	printf("regr: %x\n", regr);
+
+	for (regr = 0; regr < 100; regr++) {
+		asm volatile("mrc p15, 0, %0, c9, c13, 0" : "=r" (a));
+		asm volatile("mrc p15, 0, %0, c9, c13, 0" : "=r" (b));
+		regr += (b - a);
+	}
+
+	regr /= 100;
+	printf("Measurement overhead: %u\n", regr);
+	regr = 0;
+	while (regr < 100)	{
+		asm volatile("mrc p15, 0, %0, c9, c13, 0" : "=r" (a));
+		pid = fork();
+		asm volatile("mrc p15, 0, %0, c9, c13, 0" : "=r" (b));
+		printf("Time for fork: %u\n", b - a);
+		avg += (b - a);
+		regr++;
+		kill(pid, SIGKILL);
+	}
+
+	printf("Fork avg: %u\n", avg/100);
+	return 1; 
+}
-- 
1.9.1