Currently the global_ops filtering hash is not available to outside
users registering for function tracing. Provide an API for those
users to be able to choose global filtering.
This is in preparation for pstore's ftrace feature to be able to
use the global filters.
Suggested-by: Steven Rostedt <[email protected]>
Cc: Anton Vorontsov <[email protected]>
Cc: Colin Cross <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Tony Luck <[email protected]>
Signed-off-by: Joel Fernandes <[email protected]>
---
v2 changes: don't set global filter if ops were initialized before.
include/linux/ftrace.h | 2 ++
kernel/trace/ftrace.c | 17 +++++++++++++++++
2 files changed, 19 insertions(+)
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index b3d34d3..d4a884d 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -398,6 +398,7 @@ int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
void ftrace_set_global_filter(unsigned char *buf, int len, int reset);
void ftrace_set_global_notrace(unsigned char *buf, int len, int reset);
void ftrace_free_filter(struct ftrace_ops *ops);
+void ftrace_ops_set_global_filter(struct ftrace_ops *ops);
int register_ftrace_command(struct ftrace_func_command *cmd);
int unregister_ftrace_command(struct ftrace_func_command *cmd);
@@ -645,6 +646,7 @@ static inline unsigned long ftrace_location(unsigned long ip)
#define ftrace_set_filter(ops, buf, len, reset) ({ -ENODEV; })
#define ftrace_set_notrace(ops, buf, len, reset) ({ -ENODEV; })
#define ftrace_free_filter(ops) do { } while (0)
+#define ftrace_ops_set_global_filter(ops) do { } while (0)
static inline ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
size_t cnt, loff_t *ppos) { return -ENODEV; }
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index da87b3c..33dd57f 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -4258,6 +4258,23 @@ int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
}
EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
+/**
+ * ftrace_ops_set_global_filter - setup ops to use global filters
+ * @ops - the ops which will use the global filters
+ *
+ * ftrace users who need global function trace filtering should call this.
+ * It can set the global filter only if ops were not initialized before.
+ */
+void ftrace_ops_set_global_filter(struct ftrace_ops *ops)
+{
+ if (ops->flags & FTRACE_OPS_FL_INITIALIZED)
+ return;
+
+ ftrace_ops_init(ops);
+ ops->func_hash = &global_ops.local_hash;
+}
+EXPORT_SYMBOL_GPL(ftrace_ops_set_global_filter);
+
static int
ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
int reset, int enable)
--
2.8.0.rc3.226.g39d4020
Currently, pstore doesn't have any filters setup for function tracing. This
has the associated overhead and may not be useful for users looking for tracing
specific set of functions.
ftrace's regular function trace filtering is done writing to
tracing/set_ftrace_filter however this is not available if not requested.
Inorder to be able to use this feature, the support to request global filtering
introduced earlier in the series should be requested before registering the
ftrace ops. Here we do the same.
Signed-off-by: Joel Fernandes <[email protected]>
---
fs/pstore/ftrace.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/fs/pstore/ftrace.c b/fs/pstore/ftrace.c
index d488770..6887fbe 100644
--- a/fs/pstore/ftrace.c
+++ b/fs/pstore/ftrace.c
@@ -71,10 +71,13 @@ static ssize_t pstore_ftrace_knob_write(struct file *f, const char __user *buf,
if (!on ^ pstore_ftrace_enabled)
goto out;
- if (on)
+ if (on) {
+ ftrace_ops_set_global_filter(&pstore_ftrace_ops);
ret = register_ftrace_function(&pstore_ftrace_ops);
- else
+ } else {
ret = unregister_ftrace_function(&pstore_ftrace_ops);
+ }
+
if (ret) {
pr_err("%s: unable to %sregister ftrace ops: %zd\n",
__func__, on ? "" : "un", ret);
--
2.8.0.rc3.226.g39d4020
On Tue, 15 Nov 2016 12:31:20 -0800
Joel Fernandes <[email protected]> wrote:
> Currently the global_ops filtering hash is not available to outside
> users registering for function tracing. Provide an API for those
> users to be able to choose global filtering.
>
> This is in preparation for pstore's ftrace feature to be able to
> use the global filters.
>
> Suggested-by: Steven Rostedt <[email protected]>
Acked-by: Steven Rostedt <[email protected]>
Feel free to pull this in through the pstore tree.
-- Steve
On Tue, Nov 15, 2016 at 12:38 PM, Steven Rostedt <[email protected]> wrote:
> On Tue, 15 Nov 2016 12:31:20 -0800
> Joel Fernandes <[email protected]> wrote:
>
>> Currently the global_ops filtering hash is not available to outside
>> users registering for function tracing. Provide an API for those
>> users to be able to choose global filtering.
>>
>> This is in preparation for pstore's ftrace feature to be able to
>> use the global filters.
>>
>> Suggested-by: Steven Rostedt <[email protected]>
>
> Acked-by: Steven Rostedt <[email protected]>
>
> Feel free to pull this in through the pstore tree.
Okay, thanks. It should be in -next shortly...
-Kees
--
Kees Cook
Nexus Security