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Diffstat (limited to 'kernel/trace/ftrace.c')
-rw-r--r--kernel/trace/ftrace.c157
1 files changed, 109 insertions, 48 deletions
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 908038f5744..c3e4575e782 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -32,7 +32,6 @@
#include <trace/events/sched.h>
-#include <asm/ftrace.h>
#include <asm/setup.h>
#include "trace_output.h"
@@ -82,14 +81,14 @@ static int ftrace_disabled __read_mostly;
static DEFINE_MUTEX(ftrace_lock);
-static struct ftrace_ops ftrace_list_end __read_mostly =
-{
+static struct ftrace_ops ftrace_list_end __read_mostly = {
.func = ftrace_stub,
};
static struct ftrace_ops *ftrace_global_list __read_mostly = &ftrace_list_end;
static struct ftrace_ops *ftrace_ops_list __read_mostly = &ftrace_list_end;
ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
+static ftrace_func_t __ftrace_trace_function_delay __read_mostly = ftrace_stub;
ftrace_func_t __ftrace_trace_function __read_mostly = ftrace_stub;
ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub;
static struct ftrace_ops global_ops;
@@ -148,9 +147,11 @@ void clear_ftrace_function(void)
{
ftrace_trace_function = ftrace_stub;
__ftrace_trace_function = ftrace_stub;
+ __ftrace_trace_function_delay = ftrace_stub;
ftrace_pid_function = ftrace_stub;
}
+#undef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
#ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
/*
* For those archs that do not test ftrace_trace_stop in their
@@ -210,7 +211,12 @@ static void update_ftrace_function(void)
#ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
ftrace_trace_function = func;
#else
+#ifdef CONFIG_DYNAMIC_FTRACE
+ /* do not update till all functions have been modified */
+ __ftrace_trace_function_delay = func;
+#else
__ftrace_trace_function = func;
+#endif
ftrace_trace_function = ftrace_test_stop_func;
#endif
}
@@ -785,8 +791,7 @@ static void unregister_ftrace_profiler(void)
unregister_ftrace_graph();
}
#else
-static struct ftrace_ops ftrace_profile_ops __read_mostly =
-{
+static struct ftrace_ops ftrace_profile_ops __read_mostly = {
.func = function_profile_call,
};
@@ -806,19 +811,10 @@ ftrace_profile_write(struct file *filp, const char __user *ubuf,
size_t cnt, loff_t *ppos)
{
unsigned long val;
- char buf[64]; /* big enough to hold a number */
int ret;
- if (cnt >= sizeof(buf))
- return -EINVAL;
-
- if (copy_from_user(&buf, ubuf, cnt))
- return -EFAULT;
-
- buf[cnt] = 0;
-
- ret = strict_strtoul(buf, 10, &val);
- if (ret < 0)
+ ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
+ if (ret)
return ret;
val = !!val;
@@ -1182,8 +1178,14 @@ alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
return NULL;
}
+static void
+ftrace_hash_rec_disable(struct ftrace_ops *ops, int filter_hash);
+static void
+ftrace_hash_rec_enable(struct ftrace_ops *ops, int filter_hash);
+
static int
-ftrace_hash_move(struct ftrace_hash **dst, struct ftrace_hash *src)
+ftrace_hash_move(struct ftrace_ops *ops, int enable,
+ struct ftrace_hash **dst, struct ftrace_hash *src)
{
struct ftrace_func_entry *entry;
struct hlist_node *tp, *tn;
@@ -1193,9 +1195,16 @@ ftrace_hash_move(struct ftrace_hash **dst, struct ftrace_hash *src)
unsigned long key;
int size = src->count;
int bits = 0;
+ int ret;
int i;
/*
+ * Remove the current set, update the hash and add
+ * them back.
+ */
+ ftrace_hash_rec_disable(ops, enable);
+
+ /*
* If the new source is empty, just free dst and assign it
* the empty_hash.
*/
@@ -1215,9 +1224,10 @@ ftrace_hash_move(struct ftrace_hash **dst, struct ftrace_hash *src)
if (bits > FTRACE_HASH_MAX_BITS)
bits = FTRACE_HASH_MAX_BITS;
+ ret = -ENOMEM;
new_hash = alloc_ftrace_hash(bits);
if (!new_hash)
- return -ENOMEM;
+ goto out;
size = 1 << src->size_bits;
for (i = 0; i < size; i++) {
@@ -1236,7 +1246,16 @@ ftrace_hash_move(struct ftrace_hash **dst, struct ftrace_hash *src)
rcu_assign_pointer(*dst, new_hash);
free_ftrace_hash_rcu(old_hash);
- return 0;
+ ret = 0;
+ out:
+ /*
+ * Enable regardless of ret:
+ * On success, we enable the new hash.
+ * On failure, we re-enable the original hash.
+ */
+ ftrace_hash_rec_enable(ops, enable);
+
+ return ret;
}
/*
@@ -1596,6 +1615,12 @@ static int __ftrace_modify_code(void *data)
{
int *command = data;
+ /*
+ * Do not call function tracer while we update the code.
+ * We are in stop machine, no worrying about races.
+ */
+ function_trace_stop++;
+
if (*command & FTRACE_ENABLE_CALLS)
ftrace_replace_code(1);
else if (*command & FTRACE_DISABLE_CALLS)
@@ -1609,6 +1634,18 @@ static int __ftrace_modify_code(void *data)
else if (*command & FTRACE_STOP_FUNC_RET)
ftrace_disable_ftrace_graph_caller();
+#ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
+ /*
+ * For archs that call ftrace_test_stop_func(), we must
+ * wait till after we update all the function callers
+ * before we update the callback. This keeps different
+ * ops that record different functions from corrupting
+ * each other.
+ */
+ __ftrace_trace_function = __ftrace_trace_function_delay;
+#endif
+ function_trace_stop--;
+
return 0;
}
@@ -1744,10 +1781,36 @@ static cycle_t ftrace_update_time;
static unsigned long ftrace_update_cnt;
unsigned long ftrace_update_tot_cnt;
+static int ops_traces_mod(struct ftrace_ops *ops)
+{
+ struct ftrace_hash *hash;
+
+ hash = ops->filter_hash;
+ return !!(!hash || !hash->count);
+}
+
static int ftrace_update_code(struct module *mod)
{
struct dyn_ftrace *p;
cycle_t start, stop;
+ unsigned long ref = 0;
+
+ /*
+ * When adding a module, we need to check if tracers are
+ * currently enabled and if they are set to trace all functions.
+ * If they are, we need to enable the module functions as well
+ * as update the reference counts for those function records.
+ */
+ if (mod) {
+ struct ftrace_ops *ops;
+
+ for (ops = ftrace_ops_list;
+ ops != &ftrace_list_end; ops = ops->next) {
+ if (ops->flags & FTRACE_OPS_FL_ENABLED &&
+ ops_traces_mod(ops))
+ ref++;
+ }
+ }
start = ftrace_now(raw_smp_processor_id());
ftrace_update_cnt = 0;
@@ -1760,7 +1823,7 @@ static int ftrace_update_code(struct module *mod)
p = ftrace_new_addrs;
ftrace_new_addrs = p->newlist;
- p->flags = 0L;
+ p->flags = ref;
/*
* Do the initial record conversion from mcount jump
@@ -1783,7 +1846,7 @@ static int ftrace_update_code(struct module *mod)
* conversion puts the module to the correct state, thus
* passing the ftrace_make_call check.
*/
- if (ftrace_start_up) {
+ if (ftrace_start_up && ref) {
int failed = __ftrace_replace_code(p, 1);
if (failed) {
ftrace_bug(failed, p->ip);
@@ -2407,10 +2470,9 @@ ftrace_match_module_records(struct ftrace_hash *hash, char *buff, char *mod)
*/
static int
-ftrace_mod_callback(char *func, char *cmd, char *param, int enable)
+ftrace_mod_callback(struct ftrace_hash *hash,
+ char *func, char *cmd, char *param, int enable)
{
- struct ftrace_ops *ops = &global_ops;
- struct ftrace_hash *hash;
char *mod;
int ret = -EINVAL;
@@ -2430,11 +2492,6 @@ ftrace_mod_callback(char *func, char *cmd, char *param, int enable)
if (!strlen(mod))
return ret;
- if (enable)
- hash = ops->filter_hash;
- else
- hash = ops->notrace_hash;
-
ret = ftrace_match_module_records(hash, func, mod);
if (!ret)
ret = -EINVAL;
@@ -2760,7 +2817,7 @@ static int ftrace_process_regex(struct ftrace_hash *hash,
mutex_lock(&ftrace_cmd_mutex);
list_for_each_entry(p, &ftrace_commands, list) {
if (strcmp(p->name, command) == 0) {
- ret = p->func(func, command, next, enable);
+ ret = p->func(hash, func, command, next, enable);
goto out_unlock;
}
}
@@ -2857,7 +2914,11 @@ ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
ftrace_match_records(hash, buf, len);
mutex_lock(&ftrace_lock);
- ret = ftrace_hash_move(orig_hash, hash);
+ ret = ftrace_hash_move(ops, enable, orig_hash, hash);
+ if (!ret && ops->flags & FTRACE_OPS_FL_ENABLED
+ && ftrace_enabled)
+ ftrace_run_update_code(FTRACE_ENABLE_CALLS);
+
mutex_unlock(&ftrace_lock);
mutex_unlock(&ftrace_regex_lock);
@@ -3040,18 +3101,12 @@ ftrace_regex_release(struct inode *inode, struct file *file)
orig_hash = &iter->ops->notrace_hash;
mutex_lock(&ftrace_lock);
- /*
- * Remove the current set, update the hash and add
- * them back.
- */
- ftrace_hash_rec_disable(iter->ops, filter_hash);
- ret = ftrace_hash_move(orig_hash, iter->hash);
- if (!ret) {
- ftrace_hash_rec_enable(iter->ops, filter_hash);
- if (iter->ops->flags & FTRACE_OPS_FL_ENABLED
- && ftrace_enabled)
- ftrace_run_update_code(FTRACE_ENABLE_CALLS);
- }
+ ret = ftrace_hash_move(iter->ops, filter_hash,
+ orig_hash, iter->hash);
+ if (!ret && (iter->ops->flags & FTRACE_OPS_FL_ENABLED)
+ && ftrace_enabled)
+ ftrace_run_update_code(FTRACE_ENABLE_CALLS);
+
mutex_unlock(&ftrace_lock);
}
free_ftrace_hash(iter->hash);
@@ -3330,7 +3385,7 @@ static int ftrace_process_locs(struct module *mod,
{
unsigned long *p;
unsigned long addr;
- unsigned long flags;
+ unsigned long flags = 0; /* Shut up gcc */
mutex_lock(&ftrace_lock);
p = start;
@@ -3348,12 +3403,18 @@ static int ftrace_process_locs(struct module *mod,
}
/*
- * Disable interrupts to prevent interrupts from executing
- * code that is being modified.
+ * We only need to disable interrupts on start up
+ * because we are modifying code that an interrupt
+ * may execute, and the modification is not atomic.
+ * But for modules, nothing runs the code we modify
+ * until we are finished with it, and there's no
+ * reason to cause large interrupt latencies while we do it.
*/
- local_irq_save(flags);
+ if (!mod)
+ local_irq_save(flags);
ftrace_update_code(mod);
- local_irq_restore(flags);
+ if (!mod)
+ local_irq_restore(flags);
mutex_unlock(&ftrace_lock);
return 0;
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-12-12 21:41:29 +0000