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e28bb79d99
Introduce reserve/release functions to share the sampling facility between perf and oprofile. Also improve error handling for the sampling facility support in perf. Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
525 lines
12 KiB
C
525 lines
12 KiB
C
/*
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* S390 Version
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* Copyright IBM Corp. 2002, 2011
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* Author(s): Thomas Spatzier (tspat@de.ibm.com)
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* Author(s): Mahesh Salgaonkar (mahesh@linux.vnet.ibm.com)
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* Author(s): Heinz Graalfs (graalfs@linux.vnet.ibm.com)
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* Author(s): Andreas Krebbel (krebbel@linux.vnet.ibm.com)
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*
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* @remark Copyright 2002-2011 OProfile authors
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*/
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#include <linux/oprofile.h>
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#include <linux/perf_event.h>
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#include <linux/init.h>
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#include <linux/errno.h>
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#include <linux/fs.h>
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#include <linux/module.h>
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#include <asm/processor.h>
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#include "../../../drivers/oprofile/oprof.h"
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extern void s390_backtrace(struct pt_regs * const regs, unsigned int depth);
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#ifdef CONFIG_64BIT
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#include "hwsampler.h"
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#include "op_counter.h"
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#define DEFAULT_INTERVAL 4127518
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#define DEFAULT_SDBT_BLOCKS 1
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#define DEFAULT_SDB_BLOCKS 511
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static unsigned long oprofile_hw_interval = DEFAULT_INTERVAL;
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static unsigned long oprofile_min_interval;
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static unsigned long oprofile_max_interval;
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static unsigned long oprofile_sdbt_blocks = DEFAULT_SDBT_BLOCKS;
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static unsigned long oprofile_sdb_blocks = DEFAULT_SDB_BLOCKS;
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static int hwsampler_enabled;
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static int hwsampler_running; /* start_mutex must be held to change */
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static int hwsampler_available;
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static struct oprofile_operations timer_ops;
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struct op_counter_config counter_config;
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enum __force_cpu_type {
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reserved = 0, /* do not force */
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timer,
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};
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static int force_cpu_type;
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static int set_cpu_type(const char *str, struct kernel_param *kp)
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{
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if (!strcmp(str, "timer")) {
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force_cpu_type = timer;
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printk(KERN_INFO "oprofile: forcing timer to be returned "
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"as cpu type\n");
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} else {
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force_cpu_type = 0;
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}
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return 0;
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}
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module_param_call(cpu_type, set_cpu_type, NULL, NULL, 0);
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MODULE_PARM_DESC(cpu_type, "Force legacy basic mode sampling"
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"(report cpu_type \"timer\"");
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static int __oprofile_hwsampler_start(void)
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{
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int retval;
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retval = hwsampler_allocate(oprofile_sdbt_blocks, oprofile_sdb_blocks);
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if (retval)
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return retval;
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retval = hwsampler_start_all(oprofile_hw_interval);
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if (retval)
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hwsampler_deallocate();
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return retval;
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}
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static int oprofile_hwsampler_start(void)
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{
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int retval;
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hwsampler_running = hwsampler_enabled;
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if (!hwsampler_running)
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return timer_ops.start();
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retval = perf_reserve_sampling();
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if (retval)
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return retval;
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retval = __oprofile_hwsampler_start();
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if (retval)
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perf_release_sampling();
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return retval;
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}
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static void oprofile_hwsampler_stop(void)
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{
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if (!hwsampler_running) {
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timer_ops.stop();
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return;
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}
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hwsampler_stop_all();
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hwsampler_deallocate();
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perf_release_sampling();
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return;
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}
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/*
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* File ops used for:
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* /dev/oprofile/0/enabled
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* /dev/oprofile/hwsampling/hwsampler (cpu_type = timer)
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*/
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static ssize_t hwsampler_read(struct file *file, char __user *buf,
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size_t count, loff_t *offset)
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{
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return oprofilefs_ulong_to_user(hwsampler_enabled, buf, count, offset);
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}
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static ssize_t hwsampler_write(struct file *file, char const __user *buf,
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size_t count, loff_t *offset)
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{
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unsigned long val;
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int retval;
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if (*offset)
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return -EINVAL;
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retval = oprofilefs_ulong_from_user(&val, buf, count);
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if (retval <= 0)
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return retval;
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if (val != 0 && val != 1)
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return -EINVAL;
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if (oprofile_started)
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/*
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* save to do without locking as we set
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* hwsampler_running in start() when start_mutex is
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* held
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*/
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return -EBUSY;
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hwsampler_enabled = val;
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return count;
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}
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static const struct file_operations hwsampler_fops = {
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.read = hwsampler_read,
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.write = hwsampler_write,
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};
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/*
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* File ops used for:
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* /dev/oprofile/0/count
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* /dev/oprofile/hwsampling/hw_interval (cpu_type = timer)
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*
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* Make sure that the value is within the hardware range.
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*/
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static ssize_t hw_interval_read(struct file *file, char __user *buf,
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size_t count, loff_t *offset)
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{
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return oprofilefs_ulong_to_user(oprofile_hw_interval, buf,
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count, offset);
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}
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static ssize_t hw_interval_write(struct file *file, char const __user *buf,
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size_t count, loff_t *offset)
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{
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unsigned long val;
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int retval;
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if (*offset)
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return -EINVAL;
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retval = oprofilefs_ulong_from_user(&val, buf, count);
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if (retval <= 0)
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return retval;
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if (val < oprofile_min_interval)
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oprofile_hw_interval = oprofile_min_interval;
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else if (val > oprofile_max_interval)
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oprofile_hw_interval = oprofile_max_interval;
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else
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oprofile_hw_interval = val;
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return count;
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}
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static const struct file_operations hw_interval_fops = {
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.read = hw_interval_read,
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.write = hw_interval_write,
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};
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/*
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* File ops used for:
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* /dev/oprofile/0/event
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* Only a single event with number 0 is supported with this counter.
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*
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* /dev/oprofile/0/unit_mask
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* This is a dummy file needed by the user space tools.
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* No value other than 0 is accepted or returned.
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*/
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static ssize_t hwsampler_zero_read(struct file *file, char __user *buf,
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size_t count, loff_t *offset)
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{
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return oprofilefs_ulong_to_user(0, buf, count, offset);
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}
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static ssize_t hwsampler_zero_write(struct file *file, char const __user *buf,
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size_t count, loff_t *offset)
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{
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unsigned long val;
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int retval;
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if (*offset)
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return -EINVAL;
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retval = oprofilefs_ulong_from_user(&val, buf, count);
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if (retval <= 0)
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return retval;
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if (val != 0)
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return -EINVAL;
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return count;
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}
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static const struct file_operations zero_fops = {
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.read = hwsampler_zero_read,
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.write = hwsampler_zero_write,
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};
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/* /dev/oprofile/0/kernel file ops. */
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static ssize_t hwsampler_kernel_read(struct file *file, char __user *buf,
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size_t count, loff_t *offset)
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{
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return oprofilefs_ulong_to_user(counter_config.kernel,
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buf, count, offset);
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}
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static ssize_t hwsampler_kernel_write(struct file *file, char const __user *buf,
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size_t count, loff_t *offset)
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{
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unsigned long val;
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int retval;
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if (*offset)
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return -EINVAL;
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retval = oprofilefs_ulong_from_user(&val, buf, count);
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if (retval <= 0)
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return retval;
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if (val != 0 && val != 1)
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return -EINVAL;
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counter_config.kernel = val;
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return count;
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}
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static const struct file_operations kernel_fops = {
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.read = hwsampler_kernel_read,
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.write = hwsampler_kernel_write,
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};
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/* /dev/oprofile/0/user file ops. */
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static ssize_t hwsampler_user_read(struct file *file, char __user *buf,
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size_t count, loff_t *offset)
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{
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return oprofilefs_ulong_to_user(counter_config.user,
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buf, count, offset);
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}
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static ssize_t hwsampler_user_write(struct file *file, char const __user *buf,
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size_t count, loff_t *offset)
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{
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unsigned long val;
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int retval;
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if (*offset)
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return -EINVAL;
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retval = oprofilefs_ulong_from_user(&val, buf, count);
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if (retval <= 0)
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return retval;
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if (val != 0 && val != 1)
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return -EINVAL;
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counter_config.user = val;
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return count;
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}
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static const struct file_operations user_fops = {
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.read = hwsampler_user_read,
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.write = hwsampler_user_write,
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};
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/*
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* File ops used for: /dev/oprofile/timer/enabled
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* The value always has to be the inverted value of hwsampler_enabled. So
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* no separate variable is created. That way we do not need locking.
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*/
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static ssize_t timer_enabled_read(struct file *file, char __user *buf,
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size_t count, loff_t *offset)
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{
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return oprofilefs_ulong_to_user(!hwsampler_enabled, buf, count, offset);
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}
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static ssize_t timer_enabled_write(struct file *file, char const __user *buf,
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size_t count, loff_t *offset)
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{
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unsigned long val;
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int retval;
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if (*offset)
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return -EINVAL;
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retval = oprofilefs_ulong_from_user(&val, buf, count);
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if (retval <= 0)
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return retval;
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if (val != 0 && val != 1)
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return -EINVAL;
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/* Timer cannot be disabled without having hardware sampling. */
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if (val == 0 && !hwsampler_available)
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return -EINVAL;
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if (oprofile_started)
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/*
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* save to do without locking as we set
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* hwsampler_running in start() when start_mutex is
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* held
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*/
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return -EBUSY;
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hwsampler_enabled = !val;
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return count;
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}
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static const struct file_operations timer_enabled_fops = {
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.read = timer_enabled_read,
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.write = timer_enabled_write,
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};
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static int oprofile_create_hwsampling_files(struct dentry *root)
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{
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struct dentry *dir;
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dir = oprofilefs_mkdir(root, "timer");
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if (!dir)
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return -EINVAL;
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oprofilefs_create_file(dir, "enabled", &timer_enabled_fops);
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if (!hwsampler_available)
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return 0;
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/* reinitialize default values */
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hwsampler_enabled = 1;
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counter_config.kernel = 1;
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counter_config.user = 1;
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if (!force_cpu_type) {
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/*
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* Create the counter file system. A single virtual
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* counter is created which can be used to
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* enable/disable hardware sampling dynamically from
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* user space. The user space will configure a single
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* counter with a single event. The value of 'event'
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* and 'unit_mask' are not evaluated by the kernel code
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* and can only be set to 0.
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*/
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dir = oprofilefs_mkdir(root, "0");
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if (!dir)
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return -EINVAL;
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oprofilefs_create_file(dir, "enabled", &hwsampler_fops);
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oprofilefs_create_file(dir, "event", &zero_fops);
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oprofilefs_create_file(dir, "count", &hw_interval_fops);
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oprofilefs_create_file(dir, "unit_mask", &zero_fops);
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oprofilefs_create_file(dir, "kernel", &kernel_fops);
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oprofilefs_create_file(dir, "user", &user_fops);
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oprofilefs_create_ulong(dir, "hw_sdbt_blocks",
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&oprofile_sdbt_blocks);
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} else {
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/*
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* Hardware sampling can be used but the cpu_type is
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* forced to timer in order to deal with legacy user
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* space tools. The /dev/oprofile/hwsampling fs is
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* provided in that case.
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*/
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dir = oprofilefs_mkdir(root, "hwsampling");
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if (!dir)
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return -EINVAL;
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oprofilefs_create_file(dir, "hwsampler",
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&hwsampler_fops);
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oprofilefs_create_file(dir, "hw_interval",
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&hw_interval_fops);
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oprofilefs_create_ro_ulong(dir, "hw_min_interval",
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&oprofile_min_interval);
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oprofilefs_create_ro_ulong(dir, "hw_max_interval",
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&oprofile_max_interval);
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oprofilefs_create_ulong(dir, "hw_sdbt_blocks",
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&oprofile_sdbt_blocks);
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}
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return 0;
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}
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static int oprofile_hwsampler_init(struct oprofile_operations *ops)
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{
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/*
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* Initialize the timer mode infrastructure as well in order
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* to be able to switch back dynamically. oprofile_timer_init
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* is not supposed to fail.
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*/
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if (oprofile_timer_init(ops))
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BUG();
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memcpy(&timer_ops, ops, sizeof(timer_ops));
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ops->create_files = oprofile_create_hwsampling_files;
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/*
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* If the user space tools do not support newer cpu types,
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* the force_cpu_type module parameter
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* can be used to always return \"timer\" as cpu type.
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*/
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if (force_cpu_type != timer) {
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struct cpuid id;
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get_cpu_id (&id);
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switch (id.machine) {
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case 0x2097: case 0x2098: ops->cpu_type = "s390/z10"; break;
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case 0x2817: case 0x2818: ops->cpu_type = "s390/z196"; break;
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case 0x2827: case 0x2828: ops->cpu_type = "s390/zEC12"; break;
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default: return -ENODEV;
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}
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}
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if (hwsampler_setup())
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return -ENODEV;
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/*
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* Query the range for the sampling interval from the
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* hardware.
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*/
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oprofile_min_interval = hwsampler_query_min_interval();
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if (oprofile_min_interval == 0)
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return -ENODEV;
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oprofile_max_interval = hwsampler_query_max_interval();
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if (oprofile_max_interval == 0)
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return -ENODEV;
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/* The initial value should be sane */
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if (oprofile_hw_interval < oprofile_min_interval)
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oprofile_hw_interval = oprofile_min_interval;
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if (oprofile_hw_interval > oprofile_max_interval)
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oprofile_hw_interval = oprofile_max_interval;
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printk(KERN_INFO "oprofile: System z hardware sampling "
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"facility found.\n");
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ops->start = oprofile_hwsampler_start;
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ops->stop = oprofile_hwsampler_stop;
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return 0;
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}
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static void oprofile_hwsampler_exit(void)
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{
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hwsampler_shutdown();
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}
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#endif /* CONFIG_64BIT */
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int __init oprofile_arch_init(struct oprofile_operations *ops)
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{
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ops->backtrace = s390_backtrace;
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#ifdef CONFIG_64BIT
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/*
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* -ENODEV is not reported to the caller. The module itself
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* will use the timer mode sampling as fallback and this is
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* always available.
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*/
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hwsampler_available = oprofile_hwsampler_init(ops) == 0;
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return 0;
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#else
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return -ENODEV;
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#endif
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}
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void oprofile_arch_exit(void)
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{
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#ifdef CONFIG_64BIT
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oprofile_hwsampler_exit();
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#endif
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}
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