More oprofile bits for MIPS32-style performance counters. The code to

bolt this into the actual hardware interrupt is yet missing from this
commit.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

 FEXPORT(ret_from_fork)

arch/mips/oprofile/Kconfig

@@ -11,7 +11,7 @@ config PROFILING
 
 config OPROFILE
 	tristate "OProfile system profiling (EXPERIMENTAL)"
-	depends on PROFILING
+	depends on PROFILING && EXPERIMENTAL
 	help
 	  OProfile is a profiling system capable of profiling the
 	  whole system, include the kernel, kernel modules, libraries,

arch/mips/oprofile/common.c

@@ -3,7 +3,8 @@
  * License.  See the file "COPYING" in the main directory of this archive
  * for more details.
  *
- * Copyright (C) 2004 by Ralf Baechle
+ * Copyright (C) 2004, 2005 Ralf Baechle
+ * Copyright (C) 2005 MIPS Technologies, Inc.
  */
 #include <linux/errno.h>
 #include <linux/init.h>
@@ -45,10 +46,10 @@ static int op_mips_create_files(struct super_block * sb, struct dentry * root)
 		oprofilefs_create_ulong(sb, dir, "enabled", &ctr[i].enabled);
 		oprofilefs_create_ulong(sb, dir, "event", &ctr[i].event);
 		oprofilefs_create_ulong(sb, dir, "count", &ctr[i].count);
-		/* Dummies.  */
 		oprofilefs_create_ulong(sb, dir, "kernel", &ctr[i].kernel);
 		oprofilefs_create_ulong(sb, dir, "user", &ctr[i].user);
 		oprofilefs_create_ulong(sb, dir, "exl", &ctr[i].exl);
+		/* Dummy.  */
 		oprofilefs_create_ulong(sb, dir, "unit_mask", &ctr[i].unit_mask);
 	}
 
@@ -68,9 +69,10 @@ static void op_mips_stop(void)
 	on_each_cpu(model->cpu_stop, NULL, 0, 1);
 }
 
-void __init oprofile_arch_init(struct oprofile_operations *ops)
+int __init oprofile_arch_init(struct oprofile_operations *ops)
 {
 	struct op_mips_model *lmodel = NULL;
+	int res;
 
 	switch (current_cpu_data.cputype) {
 	case CPU_24K:
@@ -83,21 +85,25 @@ void __init oprofile_arch_init(struct oprofile_operations *ops)
 	};
 
 	if (!lmodel)
-		return;
+		return -ENODEV;
 
-	if (lmodel->init())
-		return;
+	res = lmodel->init();
+	if (res)
+		return res;
 
 	model = lmodel;
 
 	ops->create_files	= op_mips_create_files;
 	ops->setup		= op_mips_setup;
+	//ops->shutdown         = op_mips_shutdown;
 	ops->start		= op_mips_start;
 	ops->stop		= op_mips_stop;
 	ops->cpu_type		= lmodel->cpu_type;
 
 	printk(KERN_INFO "oprofile: using %s performance monitoring.\n",
 	       lmodel->cpu_type);
+
+	return 0;
 }
 
 void oprofile_arch_exit(void)

arch/mips/oprofile/op_impl.h

@@ -10,6 +10,11 @@
 #ifndef OP_IMPL_H
 #define OP_IMPL_H 1
 
+struct pt_regs;
+
+extern void null_perf_irq(struct pt_regs *regs);
+extern void (*perf_irq)(struct pt_regs *regs);
+
 /* Per-counter configuration as set via oprofilefs.  */
 struct op_counter_config {
 	unsigned long enabled;

arch/mips/oprofile/op_model_mipsxx.c

+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 2004, 2005 by Ralf Baechle
+ * Copyright (C) 2005 by MIPS Technologies, Inc.
+ */
+#include <linux/oprofile.h>
+#include <linux/interrupt.h>
+#include <linux/smp.h>
+
+#include "op_impl.h"
+
+#define M_PERFCTL_EXL			(1UL    <<  0)
+#define M_PERFCTL_KERNEL		(1UL    <<  1)
+#define M_PERFCTL_SUPERVISOR		(1UL    <<  2)
+#define M_PERFCTL_USER			(1UL    <<  3)
+#define M_PERFCTL_INTERRUPT_ENABLE	(1UL    <<  4)
+#define M_PERFCTL_EVENT(event)		((event) << 5)
+#define M_PERFCTL_WIDE			(1UL    << 30)
+#define M_PERFCTL_MORE			(1UL    << 31)
+
+#define M_COUNTER_OVERFLOW		(1UL    << 31)
+
+struct op_mips_model op_model_mipsxx;
+
+static struct mipsxx_register_config {
+	unsigned int control[4];
+	unsigned int counter[4];
+} reg;
+
+/* Compute all of the registers in preparation for enabling profiling.  */
+
+static void mipsxx_reg_setup(struct op_counter_config *ctr)
+{
+	unsigned int counters = op_model_mipsxx.num_counters;
+	int i;
+
+	/* Compute the performance counter control word.  */
+	/* For now count kernel and user mode */
+	for (i = 0; i < counters; i++) {
+		reg.control[i] = 0;
+		reg.counter[i] = 0;
+
+		if (!ctr[i].enabled)
+			continue;
+
+		reg.control[i] = M_PERFCTL_EVENT(ctr[i].event) |
+		                 M_PERFCTL_INTERRUPT_ENABLE;
+		if (ctr[i].kernel)
+			reg.control[i] |= M_PERFCTL_KERNEL;
+		if (ctr[i].user)
+			reg.control[i] |= M_PERFCTL_USER;
+		if (ctr[i].exl)
+			reg.control[i] |= M_PERFCTL_EXL;
+		reg.counter[i] = 0x80000000 - ctr[i].count;
+	}
+}
+
+/* Program all of the registers in preparation for enabling profiling.  */
+
+static void mipsxx_cpu_setup (void *args)
+{
+	unsigned int counters = op_model_mipsxx.num_counters;
+
+	switch (counters) {
+	case 4:
+		write_c0_perfctrl3(0);
+		write_c0_perfcntr3(reg.counter[3]);
+	case 3:
+		write_c0_perfctrl2(0);
+		write_c0_perfcntr2(reg.counter[2]);
+	case 2:
+		write_c0_perfctrl1(0);
+		write_c0_perfcntr1(reg.counter[1]);
+	case 1:
+		write_c0_perfctrl0(0);
+		write_c0_perfcntr0(reg.counter[0]);
+	}
+}
+
+/* Start all counters on current CPU */
+static void mipsxx_cpu_start(void *args)
+{
+	unsigned int counters = op_model_mipsxx.num_counters;
+
+	switch (counters) {
+	case 4:
+		write_c0_perfctrl3(reg.control[3]);
+	case 3:
+		write_c0_perfctrl2(reg.control[2]);
+	case 2:
+		write_c0_perfctrl1(reg.control[1]);
+	case 1:
+		write_c0_perfctrl0(reg.control[0]);
+	}
+}
+
+/* Stop all counters on current CPU */
+static void mipsxx_cpu_stop(void *args)
+{
+	unsigned int counters = op_model_mipsxx.num_counters;
+
+	switch (counters) {
+	case 4:
+		write_c0_perfctrl3(0);
+	case 3:
+		write_c0_perfctrl2(0);
+	case 2:
+		write_c0_perfctrl1(0);
+	case 1:
+		write_c0_perfctrl0(0);
+	}
+}
+
+static void mipsxx_perfcount_handler(struct pt_regs *regs)
+{
+	unsigned int counters = op_model_mipsxx.num_counters;
+	unsigned int control;
+	unsigned int counter;
+
+	switch (counters) {
+#define HANDLE_COUNTER(n)						\
+	case n + 1:							\
+		control = read_c0_perfctrl ## n();			\
+		counter = read_c0_perfcntr ## n();			\
+		if ((control & M_PERFCTL_INTERRUPT_ENABLE) &&		\
+		    (counter & M_COUNTER_OVERFLOW)) {			\
+			oprofile_add_sample(regs, n);			\
+			write_c0_perfcntr ## n(reg.counter[n]);		\
+		}
+	HANDLE_COUNTER(3)
+	HANDLE_COUNTER(2)
+	HANDLE_COUNTER(1)
+	HANDLE_COUNTER(0)
+	}
+}
+
+#define M_CONFIG1_PC	(1 << 4)
+
+static inline int n_counters(void)
+{
+	if (!(read_c0_config1() & M_CONFIG1_PC))
+		return 0;
+	if (!(read_c0_perfctrl0() & M_PERFCTL_MORE))
+		return 1;
+	if (!(read_c0_perfctrl1() & M_PERFCTL_MORE))
+		return 2;
+	if (!(read_c0_perfctrl2() & M_PERFCTL_MORE))
+		return 3;
+
+	return 4;
+}
+
+static inline void reset_counters(int counters)
+{
+	switch (counters) {
+	case 4:
+		write_c0_perfctrl3(0);
+		write_c0_perfcntr3(0);
+	case 3:
+		write_c0_perfctrl2(0);
+		write_c0_perfcntr2(0);
+	case 2:
+		write_c0_perfctrl1(0);
+		write_c0_perfcntr1(0);
+	case 1:
+		write_c0_perfctrl0(0);
+		write_c0_perfcntr0(0);
+	}
+}
+
+static int __init mipsxx_init(void)
+{
+	int counters;
+
+	counters = n_counters();
+	if (counters == 0)
+		return -ENODEV;
+
+	reset_counters(counters);
+
+	op_model_mipsxx.num_counters = counters;
+	switch (current_cpu_data.cputype) {
+	case CPU_24K:
+		op_model_mipsxx.cpu_type = "mips/24K";
+		break;
+
+	default:
+		printk(KERN_ERR "Profiling unsupported for this CPU\n");
+
+		return -ENODEV;
+	}
+
+	perf_irq = mipsxx_perfcount_handler;
+
+	return 0;
+}
+
+static void mipsxx_exit(void)
+{
+	reset_counters(op_model_mipsxx.num_counters);
+
+	perf_irq = null_perf_irq;
+}
+
+struct op_mips_model op_model_mipsxx = {
+	.reg_setup	= mipsxx_reg_setup,
+	.cpu_setup	= mipsxx_cpu_setup,
+	.init		= mipsxx_init,
+	.exit		= mipsxx_exit,
+	.cpu_start	= mipsxx_cpu_start,
+	.cpu_stop	= mipsxx_cpu_stop,
+};