[PATCH] oprofile perfmon support take 2

[John Levon <levon@movementarian.org>]

My previous patch was buggy; due to the way interaction with userspace
works, we could have left samples arriving after the sample buffers were
deleted. The simplest solution is to block samples if they arrive.

regards
john


Index: linux-cvs//arch/ia64/oprofile/Makefile
=================================RCS file: /home/cvs/linux-2.5/arch/ia64/oprofile/Makefile,v
retrieving revision 1.2
diff -u -a -p -r1.2 Makefile
--- linux-cvs//arch/ia64/oprofile/Makefile	9 Sep 2003 16:07:11 -0000	1.2
+++ linux-cvs//arch/ia64/oprofile/Makefile	21 Oct 2003 19:21:43 -0000
@@ -7,3 +7,4 @@ DRIVER_OBJS := $(addprefix ../../../driv
 		timer_int.o )
 
 oprofile-y := $(DRIVER_OBJS) init.o
+oprofile-$(CONFIG_PERFMON) += perfmon.o
Index: linux-cvs//arch/ia64/oprofile/init.c
=================================RCS file: /home/cvs/linux-2.5/arch/ia64/oprofile/init.c,v
retrieving revision 1.2
diff -u -a -p -r1.2 init.c
--- linux-cvs//arch/ia64/oprofile/init.c	9 Sep 2003 16:07:11 -0000	1.2
+++ linux-cvs//arch/ia64/oprofile/init.c	21 Oct 2003 19:21:43 -0000
@@ -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
 }
--- /dev/null	Thu Aug 21 13:36:33 2003
+++ linux-cvs/arch/ia64/oprofile/perfmon.c	Tue Oct 21 13:49:00 2003
@@ -0,0 +1,105 @@
+/**
+ * @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);
+}