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linux-next/arch/avr32/oprofile/op_model_avr32.c
Nikolaus Voss 3d25615147 Add kernel support for oprofile callgraphs on AVR32
This patch adds backtracing capability to oprofile profiling in kernel
and user mode on AVR32. This is done by going through the frames on the
stack and adding oprofile traces for all return addresses. The code
being profiled has to be compiled with frame pointers to make this work.

Signed-off-by: Nikolaus Voss <n.voss@weinmann.de>
Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
2008-09-22 09:51:01 +02:00

239 lines
5.1 KiB
C

/*
* AVR32 Performance Counter Driver
*
* Copyright (C) 2005-2007 Atmel Corporation
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* Author: Ronny Pedersen
*/
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/oprofile.h>
#include <linux/sched.h>
#include <linux/types.h>
#include <asm/sysreg.h>
#include <asm/system.h>
#define AVR32_PERFCTR_IRQ_GROUP 0
#define AVR32_PERFCTR_IRQ_LINE 1
void avr32_backtrace(struct pt_regs * const regs, unsigned int depth);
enum { PCCNT, PCNT0, PCNT1, NR_counter };
struct avr32_perf_counter {
unsigned long enabled;
unsigned long event;
unsigned long count;
unsigned long unit_mask;
unsigned long kernel;
unsigned long user;
u32 ie_mask;
u32 flag_mask;
};
static struct avr32_perf_counter counter[NR_counter] = {
{
.ie_mask = SYSREG_BIT(IEC),
.flag_mask = SYSREG_BIT(FC),
}, {
.ie_mask = SYSREG_BIT(IE0),
.flag_mask = SYSREG_BIT(F0),
}, {
.ie_mask = SYSREG_BIT(IE1),
.flag_mask = SYSREG_BIT(F1),
},
};
static void avr32_perf_counter_reset(void)
{
/* Reset all counter and disable/clear all interrupts */
sysreg_write(PCCR, (SYSREG_BIT(PCCR_R)
| SYSREG_BIT(PCCR_C)
| SYSREG_BIT(FC)
| SYSREG_BIT(F0)
| SYSREG_BIT(F1)));
}
static irqreturn_t avr32_perf_counter_interrupt(int irq, void *dev_id)
{
struct avr32_perf_counter *ctr = dev_id;
struct pt_regs *regs;
u32 pccr;
if (likely(!(intc_get_pending(AVR32_PERFCTR_IRQ_GROUP)
& (1 << AVR32_PERFCTR_IRQ_LINE))))
return IRQ_NONE;
regs = get_irq_regs();
pccr = sysreg_read(PCCR);
/* Clear the interrupt flags we're about to handle */
sysreg_write(PCCR, pccr);
/* PCCNT */
if (ctr->enabled && (pccr & ctr->flag_mask)) {
sysreg_write(PCCNT, -ctr->count);
oprofile_add_sample(regs, PCCNT);
}
ctr++;
/* PCNT0 */
if (ctr->enabled && (pccr & ctr->flag_mask)) {
sysreg_write(PCNT0, -ctr->count);
oprofile_add_sample(regs, PCNT0);
}
ctr++;
/* PCNT1 */
if (ctr->enabled && (pccr & ctr->flag_mask)) {
sysreg_write(PCNT1, -ctr->count);
oprofile_add_sample(regs, PCNT1);
}
return IRQ_HANDLED;
}
static int avr32_perf_counter_create_files(struct super_block *sb,
struct dentry *root)
{
struct dentry *dir;
unsigned int i;
char filename[4];
for (i = 0; i < NR_counter; i++) {
snprintf(filename, sizeof(filename), "%u", i);
dir = oprofilefs_mkdir(sb, root, filename);
oprofilefs_create_ulong(sb, dir, "enabled",
&counter[i].enabled);
oprofilefs_create_ulong(sb, dir, "event",
&counter[i].event);
oprofilefs_create_ulong(sb, dir, "count",
&counter[i].count);
/* Dummy entries */
oprofilefs_create_ulong(sb, dir, "kernel",
&counter[i].kernel);
oprofilefs_create_ulong(sb, dir, "user",
&counter[i].user);
oprofilefs_create_ulong(sb, dir, "unit_mask",
&counter[i].unit_mask);
}
return 0;
}
static int avr32_perf_counter_setup(void)
{
struct avr32_perf_counter *ctr;
u32 pccr;
int ret;
int i;
pr_debug("avr32_perf_counter_setup\n");
if (sysreg_read(PCCR) & SYSREG_BIT(PCCR_E)) {
printk(KERN_ERR
"oprofile: setup: perf counter already enabled\n");
return -EBUSY;
}
ret = request_irq(AVR32_PERFCTR_IRQ_GROUP,
avr32_perf_counter_interrupt, IRQF_SHARED,
"oprofile", counter);
if (ret)
return ret;
avr32_perf_counter_reset();
pccr = 0;
for (i = PCCNT; i < NR_counter; i++) {
ctr = &counter[i];
if (!ctr->enabled)
continue;
pr_debug("enabling counter %d...\n", i);
pccr |= ctr->ie_mask;
switch (i) {
case PCCNT:
/* PCCNT always counts cycles, so no events */
sysreg_write(PCCNT, -ctr->count);
break;
case PCNT0:
pccr |= SYSREG_BF(CONF0, ctr->event);
sysreg_write(PCNT0, -ctr->count);
break;
case PCNT1:
pccr |= SYSREG_BF(CONF1, ctr->event);
sysreg_write(PCNT1, -ctr->count);
break;
}
}
pr_debug("oprofile: writing 0x%x to PCCR...\n", pccr);
sysreg_write(PCCR, pccr);
return 0;
}
static void avr32_perf_counter_shutdown(void)
{
pr_debug("avr32_perf_counter_shutdown\n");
avr32_perf_counter_reset();
free_irq(AVR32_PERFCTR_IRQ_GROUP, counter);
}
static int avr32_perf_counter_start(void)
{
pr_debug("avr32_perf_counter_start\n");
sysreg_write(PCCR, sysreg_read(PCCR) | SYSREG_BIT(PCCR_E));
return 0;
}
static void avr32_perf_counter_stop(void)
{
pr_debug("avr32_perf_counter_stop\n");
sysreg_write(PCCR, sysreg_read(PCCR) & ~SYSREG_BIT(PCCR_E));
}
static struct oprofile_operations avr32_perf_counter_ops __initdata = {
.create_files = avr32_perf_counter_create_files,
.setup = avr32_perf_counter_setup,
.shutdown = avr32_perf_counter_shutdown,
.start = avr32_perf_counter_start,
.stop = avr32_perf_counter_stop,
.cpu_type = "avr32",
};
int __init oprofile_arch_init(struct oprofile_operations *ops)
{
if (!(current_cpu_data.features & AVR32_FEATURE_PCTR))
return -ENODEV;
memcpy(ops, &avr32_perf_counter_ops,
sizeof(struct oprofile_operations));
ops->backtrace = avr32_backtrace;
printk(KERN_INFO "oprofile: using AVR32 performance monitoring.\n");
return 0;
}
void oprofile_arch_exit(void)
{
}