#include <linux/hardirq.h>
#include <linux/kthread.h>
#include <linux/uaccess.h>
+#include <linux/kprobes.h>
#include <linux/ftrace.h>
#include <linux/sysctl.h>
#include <linux/ctype.h>
#include <linux/hash.h>
#include <linux/list.h>
+#include <asm/ftrace.h>
+
#include "trace.h"
/* ftrace_enabled is a method to turn ftrace on or off */
static struct ftrace_ops *ftrace_list __read_mostly = &ftrace_list_end;
ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
-void ftrace_list_func(unsigned long ip, unsigned long parent_ip)
+static void ftrace_list_func(unsigned long ip, unsigned long parent_ip)
{
struct ftrace_ops *op = ftrace_list;
#ifdef CONFIG_DYNAMIC_FTRACE
static struct task_struct *ftraced_task;
-static DECLARE_WAIT_QUEUE_HEAD(ftraced_waiters);
-static unsigned long ftraced_iteration_counter;
enum {
FTRACE_ENABLE_CALLS = (1 << 0),
};
static int ftrace_filtered;
+static int tracing_on;
+static int frozen_record_count;
static struct hlist_head ftrace_hash[FTRACE_HASHSIZE];
static int ftraced_trigger;
static int ftraced_suspend;
+static int ftraced_stop;
static int ftrace_record_suspend;
static struct dyn_ftrace *ftrace_free_records;
+
+#ifdef CONFIG_KPROBES
+static inline void freeze_record(struct dyn_ftrace *rec)
+{
+ if (!(rec->flags & FTRACE_FL_FROZEN)) {
+ rec->flags |= FTRACE_FL_FROZEN;
+ frozen_record_count++;
+ }
+}
+
+static inline void unfreeze_record(struct dyn_ftrace *rec)
+{
+ if (rec->flags & FTRACE_FL_FROZEN) {
+ rec->flags &= ~FTRACE_FL_FROZEN;
+ frozen_record_count--;
+ }
+}
+
+static inline int record_frozen(struct dyn_ftrace *rec)
+{
+ return rec->flags & FTRACE_FL_FROZEN;
+}
+#else
+# define freeze_record(rec) ({ 0; })
+# define unfreeze_record(rec) ({ 0; })
+# define record_frozen(rec) ({ 0; })
+#endif /* CONFIG_KPROBES */
+
+int skip_trace(unsigned long ip)
+{
+ unsigned long fl;
+ struct dyn_ftrace *rec;
+ struct hlist_node *t;
+ struct hlist_head *head;
+
+ if (frozen_record_count == 0)
+ return 0;
+
+ head = &ftrace_hash[hash_long(ip, FTRACE_HASHBITS)];
+ hlist_for_each_entry_rcu(rec, t, head, node) {
+ if (rec->ip == ip) {
+ if (record_frozen(rec)) {
+ if (rec->flags & FTRACE_FL_FAILED)
+ return 1;
+
+ if (!(rec->flags & FTRACE_FL_CONVERTED))
+ return 1;
+
+ if (!tracing_on || !ftrace_enabled)
+ return 1;
+
+ if (ftrace_filtered) {
+ fl = rec->flags & (FTRACE_FL_FILTER |
+ FTRACE_FL_NOTRACE);
+ if (!fl || (fl & FTRACE_FL_NOTRACE))
+ return 1;
+ }
+ }
+ break;
+ }
+ }
+
+ return 0;
+}
+
static inline int
ftrace_ip_in_hash(unsigned long ip, unsigned long key)
{
hlist_add_head_rcu(&node->node, &ftrace_hash[key]);
}
+/* called from kstop_machine */
+static inline void ftrace_del_hash(struct dyn_ftrace *node)
+{
+ hlist_del(&node->node);
+}
+
static void ftrace_free_rec(struct dyn_ftrace *rec)
{
/* no locking, only called from kstop_machine */
if (ftrace_ip_in_hash(ip, key))
goto out_unlock;
- /*
- * There's a slight race that the ftraced will update the
- * hash and reset here. If it is already converted, skip it.
- */
- if (ftrace_ip_converted(ip))
- goto out_unlock;
-
node = ftrace_alloc_dyn_node(ip);
if (!node)
goto out_unlock;
}
#define FTRACE_ADDR ((long)(ftrace_caller))
-#define MCOUNT_ADDR ((long)(mcount))
-static void
+static int
__ftrace_replace_code(struct dyn_ftrace *rec,
unsigned char *old, unsigned char *new, int enable)
{
unsigned long ip, fl;
- int failed;
ip = rec->ip;
* If this record is set not to trace then
* do nothing.
*
+ * If this record is set not to trace and
+ * it is enabled then disable it.
+ *
* If this record is not set to be filtered and
* it is enabled, disable it.
*/
- fl = rec->flags & (FTRACE_FL_FILTER | FTRACE_FL_ENABLED);
+
+ fl = rec->flags & (FTRACE_FL_FILTER | FTRACE_FL_NOTRACE |
+ FTRACE_FL_ENABLED);
if ((fl == (FTRACE_FL_FILTER | FTRACE_FL_ENABLED)) ||
- (fl == 0) || (rec->flags & FTRACE_FL_NOTRACE))
- return;
+ (fl == (FTRACE_FL_FILTER | FTRACE_FL_NOTRACE)) ||
+ !fl || (fl == FTRACE_FL_NOTRACE))
+ return 0;
/*
* If it is enabled disable it,
* otherwise enable it!
*/
- if (fl == FTRACE_FL_ENABLED) {
+ if (fl & FTRACE_FL_ENABLED) {
/* swap new and old */
new = old;
old = ftrace_call_replace(ip, FTRACE_ADDR);
*/
fl = rec->flags & (FTRACE_FL_NOTRACE | FTRACE_FL_ENABLED);
if (fl == FTRACE_FL_NOTRACE)
- return;
+ return 0;
new = ftrace_call_replace(ip, FTRACE_ADDR);
} else
if (enable) {
if (rec->flags & FTRACE_FL_ENABLED)
- return;
+ return 0;
rec->flags |= FTRACE_FL_ENABLED;
} else {
if (!(rec->flags & FTRACE_FL_ENABLED))
- return;
+ return 0;
rec->flags &= ~FTRACE_FL_ENABLED;
}
}
- failed = ftrace_modify_code(ip, old, new);
- if (failed) {
- unsigned long key;
- /* It is possible that the function hasn't been converted yet */
- key = hash_long(ip, FTRACE_HASHBITS);
- if (!ftrace_ip_in_hash(ip, key)) {
- rec->flags |= FTRACE_FL_FAILED;
- ftrace_free_rec(rec);
- }
-
- }
+ return ftrace_modify_code(ip, old, new);
}
static void ftrace_replace_code(int enable)
{
+ int i, failed;
unsigned char *new = NULL, *old = NULL;
struct dyn_ftrace *rec;
struct ftrace_page *pg;
- int i;
if (enable)
old = ftrace_nop_replace();
if (rec->flags & FTRACE_FL_FAILED)
continue;
- __ftrace_replace_code(rec, old, new, enable);
+ /* ignore updates to this record's mcount site */
+ if (get_kprobe((void *)rec->ip)) {
+ freeze_record(rec);
+ continue;
+ } else {
+ unfreeze_record(rec);
+ }
+
+ failed = __ftrace_replace_code(rec, old, new, enable);
+ if (failed && (rec->flags & FTRACE_FL_CONVERTED)) {
+ rec->flags |= FTRACE_FL_FAILED;
+ if ((system_state == SYSTEM_BOOTING) ||
+ !core_kernel_text(rec->ip)) {
+ ftrace_del_hash(rec);
+ ftrace_free_rec(rec);
+ }
+ }
}
}
}
ftrace_pages->next = (void *)get_zeroed_page(GFP_KERNEL);
}
-static void
+static int
ftrace_code_disable(struct dyn_ftrace *rec)
{
unsigned long ip;
failed = ftrace_modify_code(ip, call, nop);
if (failed) {
rec->flags |= FTRACE_FL_FAILED;
- ftrace_free_rec(rec);
+ return 0;
}
+ return 1;
}
+static int __ftrace_update_code(void *ignore);
+
static int __ftrace_modify_code(void *data)
{
unsigned long addr;
int *command = data;
- if (*command & FTRACE_ENABLE_CALLS)
+ if (*command & FTRACE_ENABLE_CALLS) {
+ /*
+ * Update any recorded ips now that we have the
+ * machine stopped
+ */
+ __ftrace_update_code(NULL);
ftrace_replace_code(1);
- else if (*command & FTRACE_DISABLE_CALLS)
+ tracing_on = 1;
+ } else if (*command & FTRACE_DISABLE_CALLS) {
ftrace_replace_code(0);
+ tracing_on = 0;
+ }
if (*command & FTRACE_UPDATE_TRACE_FUNC)
ftrace_update_ftrace_func(ftrace_trace_function);
static void ftrace_run_update_code(int command)
{
- stop_machine_run(__ftrace_modify_code, &command, NR_CPUS);
+ stop_machine(__ftrace_modify_code, &command, NULL);
+}
+
+void ftrace_disable_daemon(void)
+{
+ /* Stop the daemon from calling kstop_machine */
+ mutex_lock(&ftraced_lock);
+ ftraced_stop = 1;
+ mutex_unlock(&ftraced_lock);
+
+ ftrace_force_update();
+}
+
+void ftrace_enable_daemon(void)
+{
+ mutex_lock(&ftraced_lock);
+ ftraced_stop = 0;
+ mutex_unlock(&ftraced_lock);
+
+ ftrace_force_update();
}
static ftrace_func_t saved_ftrace_func;
static int __ftrace_update_code(void *ignore)
{
- struct dyn_ftrace *p;
- struct hlist_head head;
- struct hlist_node *t;
- int save_ftrace_enabled;
+ int i, save_ftrace_enabled;
cycle_t start, stop;
- int i;
+ struct dyn_ftrace *p;
+ struct hlist_node *t, *n;
+ struct hlist_head *head, temp_list;
/* Don't be recording funcs now */
+ ftrace_record_suspend++;
save_ftrace_enabled = ftrace_enabled;
ftrace_enabled = 0;
/* No locks needed, the machine is stopped! */
for (i = 0; i < FTRACE_HASHSIZE; i++) {
- if (hlist_empty(&ftrace_hash[i]))
- continue;
-
- head = ftrace_hash[i];
- INIT_HLIST_HEAD(&ftrace_hash[i]);
+ INIT_HLIST_HEAD(&temp_list);
+ head = &ftrace_hash[i];
/* all CPUS are stopped, we are safe to modify code */
- hlist_for_each_entry(p, t, &head, node) {
- ftrace_code_disable(p);
- ftrace_update_cnt++;
+ hlist_for_each_entry_safe(p, t, n, head, node) {
+ /* Skip over failed records which have not been
+ * freed. */
+ if (p->flags & FTRACE_FL_FAILED)
+ continue;
+
+ /* Unconverted records are always at the head of the
+ * hash bucket. Once we encounter a converted record,
+ * simply skip over to the next bucket. Saves ftraced
+ * some processor cycles (ftrace does its bid for
+ * global warming :-p ). */
+ if (p->flags & (FTRACE_FL_CONVERTED))
+ break;
+
+ /* Ignore updates to this record's mcount site.
+ * Reintroduce this record at the head of this
+ * bucket to attempt to "convert" it again if
+ * the kprobe on it is unregistered before the
+ * next run. */
+ if (get_kprobe((void *)p->ip)) {
+ ftrace_del_hash(p);
+ INIT_HLIST_NODE(&p->node);
+ hlist_add_head(&p->node, &temp_list);
+ freeze_record(p);
+ continue;
+ } else {
+ unfreeze_record(p);
+ }
+
+ /* convert record (i.e, patch mcount-call with NOP) */
+ if (ftrace_code_disable(p)) {
+ p->flags |= FTRACE_FL_CONVERTED;
+ ftrace_update_cnt++;
+ } else {
+ if ((system_state == SYSTEM_BOOTING) ||
+ !core_kernel_text(p->ip)) {
+ ftrace_del_hash(p);
+ ftrace_free_rec(p);
+ }
+ }
}
+ hlist_for_each_entry_safe(p, t, n, &temp_list, node) {
+ hlist_del(&p->node);
+ INIT_HLIST_NODE(&p->node);
+ hlist_add_head(&p->node, head);
+ }
}
stop = ftrace_now(raw_smp_processor_id());
ftrace_update_time = stop - start;
ftrace_update_tot_cnt += ftrace_update_cnt;
+ ftraced_trigger = 0;
ftrace_enabled = save_ftrace_enabled;
+ ftrace_record_suspend--;
return 0;
}
-static void ftrace_update_code(void)
+static int ftrace_update_code(void)
{
- if (unlikely(ftrace_disabled))
- return;
+ if (unlikely(ftrace_disabled) ||
+ !ftrace_enabled || !ftraced_trigger)
+ return 0;
- stop_machine_run(__ftrace_update_code, NULL, NR_CPUS);
+ stop_machine(__ftrace_update_code, NULL, NULL);
+
+ return 1;
}
static int ftraced(void *ignore)
mutex_lock(&ftrace_sysctl_lock);
mutex_lock(&ftraced_lock);
- if (ftrace_enabled && ftraced_trigger && !ftraced_suspend) {
- ftrace_record_suspend++;
- ftrace_update_code();
+ if (!ftraced_suspend && !ftraced_stop &&
+ ftrace_update_code()) {
usecs = nsecs_to_usecs(ftrace_update_time);
if (ftrace_update_tot_cnt > 100000) {
ftrace_update_tot_cnt = 0;
pr_info("hm, dftrace overflow: %lu change%s"
- " (%lu total) in %lu usec%s\n",
+ " (%lu total) in %lu usec%s\n",
ftrace_update_cnt,
ftrace_update_cnt != 1 ? "s" : "",
ftrace_update_tot_cnt,
ftrace_disabled = 1;
WARN_ON_ONCE(1);
}
- ftraced_trigger = 0;
- ftrace_record_suspend--;
}
- ftraced_iteration_counter++;
mutex_unlock(&ftraced_lock);
mutex_unlock(&ftrace_sysctl_lock);
- wake_up_interruptible(&ftraced_waiters);
-
ftrace_shutdown_replenish();
}
__set_current_state(TASK_RUNNING);
FTRACE_ITER_FILTER = (1 << 0),
FTRACE_ITER_CONT = (1 << 1),
FTRACE_ITER_NOTRACE = (1 << 2),
+ FTRACE_ITER_FAILURES = (1 << 3),
};
#define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
}
} else {
rec = &iter->pg->records[iter->idx++];
- if ((rec->flags & FTRACE_FL_FAILED) ||
+ if ((!(iter->flags & FTRACE_ITER_FAILURES) &&
+ (rec->flags & FTRACE_FL_FAILED)) ||
+
+ ((iter->flags & FTRACE_ITER_FAILURES) &&
+ (!(rec->flags & FTRACE_FL_FAILED) ||
+ (rec->flags & FTRACE_FL_FREE))) ||
+
((iter->flags & FTRACE_ITER_FILTER) &&
!(rec->flags & FTRACE_FL_FILTER)) ||
+
((iter->flags & FTRACE_ITER_NOTRACE) &&
!(rec->flags & FTRACE_FL_NOTRACE))) {
rec = NULL;
return 0;
}
+static int
+ftrace_failures_open(struct inode *inode, struct file *file)
+{
+ int ret;
+ struct seq_file *m;
+ struct ftrace_iterator *iter;
+
+ ret = ftrace_avail_open(inode, file);
+ if (!ret) {
+ m = (struct seq_file *)file->private_data;
+ iter = (struct ftrace_iterator *)m->private;
+ iter->flags = FTRACE_ITER_FAILURES;
+ }
+
+ return ret;
+}
+
+
static void ftrace_filter_reset(int enable)
{
struct ftrace_page *pg;
return ftrace_regex_release(inode, file, 0);
}
+static ssize_t
+ftraced_read(struct file *filp, char __user *ubuf,
+ size_t cnt, loff_t *ppos)
+{
+ /* don't worry about races */
+ char *buf = ftraced_stop ? "disabled\n" : "enabled\n";
+ int r = strlen(buf);
+
+ return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
+}
+
+static ssize_t
+ftraced_write(struct file *filp, const char __user *ubuf,
+ size_t cnt, loff_t *ppos)
+{
+ char buf[64];
+ long val;
+ int ret;
+
+ if (cnt >= sizeof(buf))
+ return -EINVAL;
+
+ if (copy_from_user(&buf, ubuf, cnt))
+ return -EFAULT;
+
+ if (strncmp(buf, "enable", 6) == 0)
+ val = 1;
+ else if (strncmp(buf, "disable", 7) == 0)
+ val = 0;
+ else {
+ buf[cnt] = 0;
+
+ ret = strict_strtoul(buf, 10, &val);
+ if (ret < 0)
+ return ret;
+
+ val = !!val;
+ }
+
+ if (val)
+ ftrace_enable_daemon();
+ else
+ ftrace_disable_daemon();
+
+ filp->f_pos += cnt;
+
+ return cnt;
+}
+
static struct file_operations ftrace_avail_fops = {
.open = ftrace_avail_open,
.read = seq_read,
.release = ftrace_avail_release,
};
+static struct file_operations ftrace_failures_fops = {
+ .open = ftrace_failures_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = ftrace_avail_release,
+};
+
static struct file_operations ftrace_filter_fops = {
.open = ftrace_filter_open,
.read = ftrace_regex_read,
.release = ftrace_notrace_release,
};
+static struct file_operations ftraced_fops = {
+ .open = tracing_open_generic,
+ .read = ftraced_read,
+ .write = ftraced_write,
+};
+
/**
* ftrace_force_update - force an update to all recording ftrace functions
- *
- * The ftrace dynamic update daemon only wakes up once a second.
- * There may be cases where an update needs to be done immediately
- * for tests or internal kernel tracing to begin. This function
- * wakes the daemon to do an update and will not return until the
- * update is complete.
*/
int ftrace_force_update(void)
{
- unsigned long last_counter;
- DECLARE_WAITQUEUE(wait, current);
int ret = 0;
if (unlikely(ftrace_disabled))
return -ENODEV;
+ mutex_lock(&ftrace_sysctl_lock);
mutex_lock(&ftraced_lock);
- last_counter = ftraced_iteration_counter;
-
- set_current_state(TASK_INTERRUPTIBLE);
- add_wait_queue(&ftraced_waiters, &wait);
-
- if (unlikely(!ftraced_task)) {
- ret = -ENODEV;
- goto out;
- }
- do {
- mutex_unlock(&ftraced_lock);
- wake_up_process(ftraced_task);
- schedule();
- mutex_lock(&ftraced_lock);
- if (signal_pending(current)) {
- ret = -EINTR;
- break;
- }
- set_current_state(TASK_INTERRUPTIBLE);
- } while (last_counter == ftraced_iteration_counter);
+ /*
+ * If ftraced_trigger is not set, then there is nothing
+ * to update.
+ */
+ if (ftraced_trigger && !ftrace_update_code())
+ ret = -EBUSY;
- out:
mutex_unlock(&ftraced_lock);
- remove_wait_queue(&ftraced_waiters, &wait);
- set_current_state(TASK_RUNNING);
+ mutex_unlock(&ftrace_sysctl_lock);
return ret;
}
pr_warning("Could not create debugfs "
"'available_filter_functions' entry\n");
+ entry = debugfs_create_file("failures", 0444,
+ d_tracer, NULL, &ftrace_failures_fops);
+ if (!entry)
+ pr_warning("Could not create debugfs 'failures' entry\n");
+
entry = debugfs_create_file("set_ftrace_filter", 0644, d_tracer,
NULL, &ftrace_filter_fops);
if (!entry)
if (!entry)
pr_warning("Could not create debugfs "
"'set_ftrace_notrace' entry\n");
+
+ entry = debugfs_create_file("ftraced_enabled", 0644, d_tracer,
+ NULL, &ftraced_fops);
+ if (!entry)
+ pr_warning("Could not create debugfs "
+ "'ftraced_enabled' entry\n");
return 0;
}
addr = (unsigned long)ftrace_record_ip;
- stop_machine_run(ftrace_dyn_arch_init, &addr, NR_CPUS);
+ stop_machine(ftrace_dyn_arch_init, &addr, NULL);
/* ftrace_dyn_arch_init places the return code in addr */
if (addr) {
# define ftrace_force_shutdown() do { } while (0)
#endif /* CONFIG_DYNAMIC_FTRACE */
+/**
+ * ftrace_kill_atomic - kill ftrace from critical sections
+ *
+ * This function should be used by panic code. It stops ftrace
+ * but in a not so nice way. If you need to simply kill ftrace
+ * from a non-atomic section, use ftrace_kill.
+ */
+void ftrace_kill_atomic(void)
+{
+ ftrace_disabled = 1;
+ ftrace_enabled = 0;
+#ifdef CONFIG_DYNAMIC_FTRACE
+ ftraced_suspend = -1;
+#endif
+ clear_ftrace_function();
+}
+
/**
* ftrace_kill - totally shutdown ftrace
*
projects / linux-2.6-omap-h63xx.git / blobdiff