1 files changed, 65 insertions, 0 deletions
diff --git a/src/geode_msr.c b/src/geode_msr.c
new file mode 100644
index 0000000..12b9f73
--- /dev/null
+++ b/src/geode_msr.c
@@ -0,0 +1,65 @@
+#define _LARGEFILE64_SOURCE
+#include <stdio.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/types.h>
+#include <sys/errno.h>
+#include "os.h"
+
+static int _msr_open(void)
+{
+  static int msrfd = 0;
+
+  if (msrfd == 0) {
+    msrfd = open("/dev/cpu/0/msr", O_RDWR);
+    if (msrfd == -1)
+      ErrorF("Unable to open /dev/cpu/0/msr: %d\n", errno);
+  }
+
+  return msrfd;
+}
+
+int GeodeReadMSR(unsigned long addr, unsigned long *lo, unsigned long *hi)
+{
+  unsigned int data[2];
+  int fd = _msr_open();
+  int ret;
+
+  if (fd == -1)
+    return -1;
+  
+  ret = lseek64(fd, (off64_t) addr, SEEK_SET);
+  
+  if (ret == -1)
+    return -1;
+  
+  ret = read(fd, (void *) data, sizeof(data));
+  
+  if (ret != 8) 
+    return -1;
+
+  *hi = data[1];
+  *lo = data[0];
+
+  return 0;
+}
+
+int GeodeWriteMSR(unsigned long addr, unsigned long lo, unsigned long hi)
+{
+  unsigned int data[2];
+  int fd = _msr_open();
+
+  if (fd == -1)
+    return - 1;
+
+  if (lseek64(fd, (off64_t) addr, SEEK_SET) == -1)
+    return -1;
+
+  data[0] = lo;
+  data[1] = hi;
+
+  if (write(fd, (void *) data, 8) != 8)
+    return -1;
+
+  return 0;
+}