128 lines
3.2 KiB
C
128 lines
3.2 KiB
C
/* Copyright (c) 2014, The Linux Foundation. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 and
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* only version 2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <linux/perf_event.h>
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#include <linux/types.h>
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#include <linux/tracepoint.h>
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#include <linux/fs.h>
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#include <linux/debugfs.h>
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#include <linux/preempt.h>
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#include <linux/stat.h>
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#include <asm/uaccess.h>
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#define CREATE_TRACE_POINTS
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#include "perf_trace_user.h"
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#undef TRACE_SYSTEM
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#define TRACE_SYSTEM perf_trace_counters
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#define TRACE_USER_MAX_BUF_SIZE 100
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u32 perf_num_l2ctrs;
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static int perf_trace_write(struct file *file,
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const char __user *user_string_in,
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size_t len, loff_t *ppos)
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{
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u32 cnten_val;
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u32 bit;
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u32 cpu;
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u32 num_cores = nr_cpu_ids;
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u32 l2_enmask;
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u32 l2_cnten_val;
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unsigned long idx;
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int i;
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int rc;
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char buf[TRACE_USER_MAX_BUF_SIZE + 1];
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int length;
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if (len == 0)
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return 0;
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length = len > TRACE_USER_MAX_BUF_SIZE ? TRACE_USER_MAX_BUF_SIZE : len;
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rc = copy_from_user(buf, user_string_in, length);
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/* Remove any trailing newline and make sure string is terminated */
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if (buf[length - 1] == '\n')
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buf[length - 1] = '\0';
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else
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buf[length] = '\0';
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/*
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* Disable preemption to ensure that all the performance counter
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* accesses happen on the same cpu
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*/
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preempt_disable();
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cpu = smp_processor_id();
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/* stop counters, call the trace function, restart them */
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/* Read PMCNTENSET */
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asm volatile("mrc p15, 0, %0, c9, c12, 1" : "=r"(cnten_val));
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/* Disable all the counters that were enabled */
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asm volatile("mcr p15, 0, %0, c9, c12, 2" : : "r"(cnten_val));
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l2_cnten_val = get_l2_indirect_reg(L2PMCNTENSET);
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l2_enmask = 0;
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for (i = 0; i < NUM_L2_PERCPU; i++) {
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/*
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* Assign L2 counters to cores sequentially
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* starting from zero. A core could have
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* multiple L2 counters allocated if # L2
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* counters is more than the # cores
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*/
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idx = cpu + (num_cores * i);
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bit = BIT(idx);
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if (idx < perf_num_l2ctrs && (l2_cnten_val & bit)) {
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/* Disable */
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set_l2_indirect_reg(L2PMCNTENCLR, bit);
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l2_enmask |= bit;
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}
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}
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trace_perf_trace_user(buf, cnten_val, l2_enmask);
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/* Enable L2*/
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set_l2_indirect_reg(L2PMCNTENSET, l2_enmask);
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/* Enable all the counters that were disabled */
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asm volatile("mcr p15, 0, %0, c9, c12, 1" : : "r"(cnten_val));
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preempt_enable();
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return length;
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}
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static const struct file_operations perf_trace_fops = {
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.write = perf_trace_write
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};
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static int __init init_perf_trace(void)
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{
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u32 val;
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struct dentry *dir;
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struct dentry *file;
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unsigned int value = 1;
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dir = perf_create_debug_dir();
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if (!dir)
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return -ENOMEM;
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file = debugfs_create_file("trace_marker", S_IWUSR | S_IWGRP, dir,
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&value, &perf_trace_fops);
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if (!file)
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return -ENOMEM;
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val = get_l2_indirect_reg(L2PMCR);
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perf_num_l2ctrs = ((val >> 11) & 0x1f) + 1;
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return 0;
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}
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late_initcall(init_perf_trace);
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