[IA64] support for IA64 hardware performance counters via the perfmon interface

 
   This patch provides support for IA64 hardware performance counters via
   the perfmon interface. Please consider applying.
Signed-off-by: John Levon <levon@movementarian.org>
Signed-off-by: Tony Luck <tony.luck@intel.com>

arch/ia64/oprofile/Kconfig

@@ -16,6 +16,10 @@ config OPROFILE
 	  whole system, include the kernel, kernel modules, libraries,
 	  and applications.
 
+	  Due to firmware bugs, you may need to use the "nohalt" boot
+	  option if you're using OProfile with the hardware performance
+	  counters.
+
 	  If unsure, say N.
 
 endmenu

arch/ia64/oprofile/Makefile

@@ -7,3 +7,4 @@ DRIVER_OBJS := $(addprefix ../../../drivers/oprofile/, \
 		timer_int.o )
 
 oprofile-y := $(DRIVER_OBJS) init.o
+oprofile-$(CONFIG_PERFMON) += perfmon.o

arch/ia64/oprofile/init.c

@@ -12,14 +12,21 @@
 #include <linux/init.h>
 #include <linux/errno.h>
  
-extern void timer_init(struct oprofile_operations ** ops);
+extern int perfmon_init(struct oprofile_operations ** ops);
+extern void perfmon_exit(void);
 
 int __init oprofile_arch_init(struct oprofile_operations ** ops)
 {
+#ifdef CONFIG_PERFMON
+	return perfmon_init(ops);
+#endif
 	return -ENODEV;
 }
 
 
 void oprofile_arch_exit(void)
 {
+#ifdef CONFIG_PERFMON
+	perfmon_exit();
+#endif
 }

arch/ia64/oprofile/perfmon.c

+/**
+ * @file perfmon.c
+ *
+ * @remark Copyright 2003 OProfile authors
+ * @remark Read the file COPYING
+ *
+ * @author John Levon <levon@movementarian.org>
+ */
+
+#include <linux/kernel.h>
+#include <linux/config.h>
+#include <linux/oprofile.h>
+#include <linux/sched.h>
+#include <asm/perfmon.h>
+#include <asm/ptrace.h>
+#include <asm/errno.h>
+
+static int allow_ints;
+
+static int
+perfmon_handler(struct task_struct *task, void *buf, pfm_ovfl_arg_t *arg,
+                struct pt_regs *regs, unsigned long stamp)
+{
+	int cpu = smp_processor_id();
+	unsigned long eip = instruction_pointer(regs);
+	int event = arg->pmd_eventid;
+ 
+	arg->ovfl_ctrl.bits.reset_ovfl_pmds = 1;
+
+	/* the owner of the oprofile event buffer may have exited
+	 * without perfmon being shutdown (e.g. SIGSEGV)
+	 */
+	if (allow_ints)
+		oprofile_add_sample(eip, !user_mode(regs), event, cpu);
+	return 0;
+}
+
+
+static int perfmon_start(void)
+{
+	allow_ints = 1;
+	return 0;
+}
+
+
+static void perfmon_stop(void)
+{
+	allow_ints = 0;
+}
+
+
+#define OPROFILE_FMT_UUID { \
+	0x77, 0x7a, 0x6e, 0x61, 0x20, 0x65, 0x73, 0x69, 0x74, 0x6e, 0x72, 0x20, 0x61, 0x65, 0x0a, 0x6c }
+
+static pfm_buffer_fmt_t oprofile_fmt = {
+ 	.fmt_name 	    = "oprofile_format",
+ 	.fmt_uuid	    = OPROFILE_FMT_UUID,
+ 	.fmt_handler	    = perfmon_handler,
+};
+
+
+static char * get_cpu_type(void)
+{
+	__u8 family = local_cpu_data->family;
+
+	switch (family) {
+		case 0x07:
+			return "ia64/itanium";
+		case 0x1f:
+			return "ia64/itanium2";
+		default:
+			return "ia64/ia64";
+	}
+}
+
+
+/* all the ops are handled via userspace for IA64 perfmon */
+static struct oprofile_operations perfmon_ops = {
+	.start = perfmon_start,
+	.stop = perfmon_stop,
+};
+
+static int using_perfmon;
+
+int perfmon_init(struct oprofile_operations ** ops)
+{
+	int ret = pfm_register_buffer_fmt(&oprofile_fmt);
+	if (ret)
+		return -ENODEV;
+
+	perfmon_ops.cpu_type = get_cpu_type();
+	*ops = &perfmon_ops;
+	using_perfmon = 1;
+	printk(KERN_INFO "oprofile: using perfmon.\n");
+	return 0;
+}
+
+
+void perfmon_exit(void)
+{
+	if (!using_perfmon)
+		return;
+
+	pfm_unregister_buffer_fmt(oprofile_fmt.fmt_uuid);
+}