+++ /dev/null
-/*
- * trace_ksym.c - Kernel Symbol Tracer
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
- *
- * Copyright (C) IBM Corporation, 2009
- */
-
-#include <linux/kallsyms.h>
-#include <linux/uaccess.h>
-#include <linux/debugfs.h>
-#include <linux/ftrace.h>
-#include <linux/module.h>
-#include <linux/slab.h>
-#include <linux/fs.h>
-
-#include "trace_output.h"
-#include "trace.h"
-
-#include <linux/hw_breakpoint.h>
-#include <asm/hw_breakpoint.h>
-
-#include <asm/atomic.h>
-
-#define KSYM_TRACER_OP_LEN 3 /* rw- */
-
-struct trace_ksym {
- struct perf_event **ksym_hbp;
- struct perf_event_attr attr;
-#ifdef CONFIG_PROFILE_KSYM_TRACER
- atomic64_t counter;
-#endif
- struct hlist_node ksym_hlist;
-};
-
-static struct trace_array *ksym_trace_array;
-
-static unsigned int ksym_tracing_enabled;
-
-static HLIST_HEAD(ksym_filter_head);
-
-static DEFINE_MUTEX(ksym_tracer_mutex);
-
-#ifdef CONFIG_PROFILE_KSYM_TRACER
-
-#define MAX_UL_INT 0xffffffff
-
-void ksym_collect_stats(unsigned long hbp_hit_addr)
-{
- struct hlist_node *node;
- struct trace_ksym *entry;
-
- rcu_read_lock();
- hlist_for_each_entry_rcu(entry, node, &ksym_filter_head, ksym_hlist) {
- if (entry->attr.bp_addr == hbp_hit_addr) {
- atomic64_inc(&entry->counter);
- break;
- }
- }
- rcu_read_unlock();
-}
-#endif /* CONFIG_PROFILE_KSYM_TRACER */
-
-void ksym_hbp_handler(struct perf_event *hbp, int nmi,
- struct perf_sample_data *data,
- struct pt_regs *regs)
-{
- struct ring_buffer_event *event;
- struct ksym_trace_entry *entry;
- struct ring_buffer *buffer;
- int pc;
-
- if (!ksym_tracing_enabled)
- return;
-
- buffer = ksym_trace_array->buffer;
-
- pc = preempt_count();
-
- event = trace_buffer_lock_reserve(buffer, TRACE_KSYM,
- sizeof(*entry), 0, pc);
- if (!event)
- return;
-
- entry = ring_buffer_event_data(event);
- entry->ip = instruction_pointer(regs);
- entry->type = hw_breakpoint_type(hbp);
- entry->addr = hw_breakpoint_addr(hbp);
- strlcpy(entry->cmd, current->comm, TASK_COMM_LEN);
-
-#ifdef CONFIG_PROFILE_KSYM_TRACER
- ksym_collect_stats(hw_breakpoint_addr(hbp));
-#endif /* CONFIG_PROFILE_KSYM_TRACER */
-
- trace_buffer_unlock_commit(buffer, event, 0, pc);
-}
-
-/* Valid access types are represented as
- *
- * rw- : Set Read/Write Access Breakpoint
- * -w- : Set Write Access Breakpoint
- * --- : Clear Breakpoints
- * --x : Set Execution Break points (Not available yet)
- *
- */
-static int ksym_trace_get_access_type(char *str)
-{
- int access = 0;
-
- if (str[0] == 'r')
- access |= HW_BREAKPOINT_R;
-
- if (str[1] == 'w')
- access |= HW_BREAKPOINT_W;
-
- if (str[2] == 'x')
- access |= HW_BREAKPOINT_X;
-
- switch (access) {
- case HW_BREAKPOINT_R:
- case HW_BREAKPOINT_W:
- case HW_BREAKPOINT_W | HW_BREAKPOINT_R:
- return access;
- default:
- return -EINVAL;
- }
-}
-
-/*
- * There can be several possible malformed requests and we attempt to capture
- * all of them. We enumerate some of the rules
- * 1. We will not allow kernel symbols with ':' since it is used as a delimiter.
- * i.e. multiple ':' symbols disallowed. Possible uses are of the form
- * <module>:<ksym_name>:<op>.
- * 2. No delimiter symbol ':' in the input string
- * 3. Spurious operator symbols or symbols not in their respective positions
- * 4. <ksym_name>:--- i.e. clear breakpoint request when ksym_name not in file
- * 5. Kernel symbol not a part of /proc/kallsyms
- * 6. Duplicate requests
- */
-static int parse_ksym_trace_str(char *input_string, char **ksymname,
- unsigned long *addr)
-{
- int ret;
-
- *ksymname = strsep(&input_string, ":");
- *addr = kallsyms_lookup_name(*ksymname);
-
- /* Check for malformed request: (2), (1) and (5) */
- if ((!input_string) ||
- (strlen(input_string) != KSYM_TRACER_OP_LEN) ||
- (*addr == 0))
- return -EINVAL;;
-
- ret = ksym_trace_get_access_type(input_string);
-
- return ret;
-}
-
-int process_new_ksym_entry(char *ksymname, int op, unsigned long addr)
-{
- struct trace_ksym *entry;
- int ret = -ENOMEM;
-
- entry = kzalloc(sizeof(struct trace_ksym), GFP_KERNEL);
- if (!entry)
- return -ENOMEM;
-
- hw_breakpoint_init(&entry->attr);
-
- entry->attr.bp_type = op;
- entry->attr.bp_addr = addr;
- entry->attr.bp_len = HW_BREAKPOINT_LEN_4;
-
- entry->ksym_hbp = register_wide_hw_breakpoint(&entry->attr,
- ksym_hbp_handler);
-
- if (IS_ERR(entry->ksym_hbp)) {
- ret = PTR_ERR(entry->ksym_hbp);
- if (ret == -ENOSPC) {
- printk(KERN_ERR "ksym_tracer: Maximum limit reached."
- " No new requests for tracing can be accepted now.\n");
- } else {
- printk(KERN_INFO "ksym_tracer request failed. Try again"
- " later!!\n");
- }
- goto err;
- }
-
- hlist_add_head_rcu(&(entry->ksym_hlist), &ksym_filter_head);
-
- return 0;
-
-err:
- kfree(entry);
-
- return ret;
-}
-
-static ssize_t ksym_trace_filter_read(struct file *filp, char __user *ubuf,
- size_t count, loff_t *ppos)
-{
- struct trace_ksym *entry;
- struct hlist_node *node;
- struct trace_seq *s;
- ssize_t cnt = 0;
- int ret;
-
- s = kmalloc(sizeof(*s), GFP_KERNEL);
- if (!s)
- return -ENOMEM;
- trace_seq_init(s);
-
- mutex_lock(&ksym_tracer_mutex);
-
- hlist_for_each_entry(entry, node, &ksym_filter_head, ksym_hlist) {
- ret = trace_seq_printf(s, "%pS:",
- (void *)(unsigned long)entry->attr.bp_addr);
- if (entry->attr.bp_type == HW_BREAKPOINT_R)
- ret = trace_seq_puts(s, "r--\n");
- else if (entry->attr.bp_type == HW_BREAKPOINT_W)
- ret = trace_seq_puts(s, "-w-\n");
- else if (entry->attr.bp_type == (HW_BREAKPOINT_W | HW_BREAKPOINT_R))
- ret = trace_seq_puts(s, "rw-\n");
- WARN_ON_ONCE(!ret);
- }
-
- cnt = simple_read_from_buffer(ubuf, count, ppos, s->buffer, s->len);
-
- mutex_unlock(&ksym_tracer_mutex);
-
- kfree(s);
-
- return cnt;
-}
-
-static void __ksym_trace_reset(void)
-{
- struct trace_ksym *entry;
- struct hlist_node *node, *node1;
-
- mutex_lock(&ksym_tracer_mutex);
- hlist_for_each_entry_safe(entry, node, node1, &ksym_filter_head,
- ksym_hlist) {
- unregister_wide_hw_breakpoint(entry->ksym_hbp);
- hlist_del_rcu(&(entry->ksym_hlist));
- synchronize_rcu();
- kfree(entry);
- }
- mutex_unlock(&ksym_tracer_mutex);
-}
-
-static ssize_t ksym_trace_filter_write(struct file *file,
- const char __user *buffer,
- size_t count, loff_t *ppos)
-{
- struct trace_ksym *entry;
- struct hlist_node *node;
- char *buf, *input_string, *ksymname = NULL;
- unsigned long ksym_addr = 0;
- int ret, op, changed = 0;
-
- buf = kzalloc(count + 1, GFP_KERNEL);
- if (!buf)
- return -ENOMEM;
-
- ret = -EFAULT;
- if (copy_from_user(buf, buffer, count))
- goto out;
-
- buf[count] = '\0';
- input_string = strstrip(buf);
-
- /*
- * Clear all breakpoints if:
- * 1: echo > ksym_trace_filter
- * 2: echo 0 > ksym_trace_filter
- * 3: echo "*:---" > ksym_trace_filter
- */
- if (!input_string[0] || !strcmp(input_string, "0") ||
- !strcmp(input_string, "*:---")) {
- __ksym_trace_reset();
- ret = 0;
- goto out;
- }
-
- ret = op = parse_ksym_trace_str(input_string, &ksymname, &ksym_addr);
- if (ret < 0)
- goto out;
-
- mutex_lock(&ksym_tracer_mutex);
-
- ret = -EINVAL;
- hlist_for_each_entry(entry, node, &ksym_filter_head, ksym_hlist) {
- if (entry->attr.bp_addr == ksym_addr) {
- /* Check for malformed request: (6) */
- if (entry->attr.bp_type != op)
- changed = 1;
- else
- goto out_unlock;
- break;
- }
- }
- if (changed) {
- unregister_wide_hw_breakpoint(entry->ksym_hbp);
- entry->attr.bp_type = op;
- ret = 0;
- if (op > 0) {
- entry->ksym_hbp =
- register_wide_hw_breakpoint(&entry->attr,
- ksym_hbp_handler);
- if (IS_ERR(entry->ksym_hbp))
- ret = PTR_ERR(entry->ksym_hbp);
- else
- goto out_unlock;
- }
- /* Error or "symbol:---" case: drop it */
- hlist_del_rcu(&(entry->ksym_hlist));
- synchronize_rcu();
- kfree(entry);
- goto out_unlock;
- } else {
- /* Check for malformed request: (4) */
- if (op)
- ret = process_new_ksym_entry(ksymname, op, ksym_addr);
- }
-out_unlock:
- mutex_unlock(&ksym_tracer_mutex);
-out:
- kfree(buf);
- return !ret ? count : ret;
-}
-
-static const struct file_operations ksym_tracing_fops = {
- .open = tracing_open_generic,
- .read = ksym_trace_filter_read,
- .write = ksym_trace_filter_write,
-};
-
-static void ksym_trace_reset(struct trace_array *tr)
-{
- ksym_tracing_enabled = 0;
- __ksym_trace_reset();
-}
-
-static int ksym_trace_init(struct trace_array *tr)
-{
- int cpu, ret = 0;
-
- for_each_online_cpu(cpu)
- tracing_reset(tr, cpu);
- ksym_tracing_enabled = 1;
- ksym_trace_array = tr;
-
- return ret;
-}
-
-static void ksym_trace_print_header(struct seq_file *m)
-{
- seq_puts(m,
- "# TASK-PID CPU# Symbol "
- "Type Function\n");
- seq_puts(m,
- "# | | | "
- " | |\n");
-}
-
-static enum print_line_t ksym_trace_output(struct trace_iterator *iter)
-{
- struct trace_entry *entry = iter->ent;
- struct trace_seq *s = &iter->seq;
- struct ksym_trace_entry *field;
- char str[KSYM_SYMBOL_LEN];
- int ret;
-
- if (entry->type != TRACE_KSYM)
- return TRACE_TYPE_UNHANDLED;
-
- trace_assign_type(field, entry);
-
- ret = trace_seq_printf(s, "%11s-%-5d [%03d] %pS", field->cmd,
- entry->pid, iter->cpu, (char *)field->addr);
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
-
- switch (field->type) {
- case HW_BREAKPOINT_R:
- ret = trace_seq_printf(s, " R ");
- break;
- case HW_BREAKPOINT_W:
- ret = trace_seq_printf(s, " W ");
- break;
- case HW_BREAKPOINT_R | HW_BREAKPOINT_W:
- ret = trace_seq_printf(s, " RW ");
- break;
- default:
- return TRACE_TYPE_PARTIAL_LINE;
- }
-
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
-
- sprint_symbol(str, field->ip);
- ret = trace_seq_printf(s, "%s\n", str);
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
-
- return TRACE_TYPE_HANDLED;
-}
-
-struct tracer ksym_tracer __read_mostly =
-{
- .name = "ksym_tracer",
- .init = ksym_trace_init,
- .reset = ksym_trace_reset,
-#ifdef CONFIG_FTRACE_SELFTEST
- .selftest = trace_selftest_startup_ksym,
-#endif
- .print_header = ksym_trace_print_header,
- .print_line = ksym_trace_output
-};
-
-#ifdef CONFIG_PROFILE_KSYM_TRACER
-static int ksym_profile_show(struct seq_file *m, void *v)
-{
- struct hlist_node *node;
- struct trace_ksym *entry;
- int access_type = 0;
- char fn_name[KSYM_NAME_LEN];
-
- seq_puts(m, " Access Type ");
- seq_puts(m, " Symbol Counter\n");
- seq_puts(m, " ----------- ");
- seq_puts(m, " ------ -------\n");
-
- rcu_read_lock();
- hlist_for_each_entry_rcu(entry, node, &ksym_filter_head, ksym_hlist) {
-
- access_type = entry->attr.bp_type;
-
- switch (access_type) {
- case HW_BREAKPOINT_R:
- seq_puts(m, " R ");
- break;
- case HW_BREAKPOINT_W:
- seq_puts(m, " W ");
- break;
- case HW_BREAKPOINT_R | HW_BREAKPOINT_W:
- seq_puts(m, " RW ");
- break;
- default:
- seq_puts(m, " NA ");
- }
-
- if (lookup_symbol_name(entry->attr.bp_addr, fn_name) >= 0)
- seq_printf(m, " %-36s", fn_name);
- else
- seq_printf(m, " %-36s", "<NA>");
- seq_printf(m, " %15llu\n",
- (unsigned long long)atomic64_read(&entry->counter));
- }
- rcu_read_unlock();
-
- return 0;
-}
-
-static int ksym_profile_open(struct inode *node, struct file *file)
-{
- return single_open(file, ksym_profile_show, NULL);
-}
-
-static const struct file_operations ksym_profile_fops = {
- .open = ksym_profile_open,
- .read = seq_read,
- .llseek = seq_lseek,
- .release = single_release,
-};
-#endif /* CONFIG_PROFILE_KSYM_TRACER */
-
-__init static int init_ksym_trace(void)
-{
- struct dentry *d_tracer;
-
- d_tracer = tracing_init_dentry();
-
- trace_create_file("ksym_trace_filter", 0644, d_tracer,
- NULL, &ksym_tracing_fops);
-
-#ifdef CONFIG_PROFILE_KSYM_TRACER
- trace_create_file("ksym_profile", 0444, d_tracer,
- NULL, &ksym_profile_fops);
-#endif
-
- return register_tracer(&ksym_tracer);
-}
-device_initcall(init_ksym_trace);
git://bbs.cooldavid.org / net-next-2.6.git / commitdiff